Faculteit der Aard- en Levenswetenschappen, Vrije Universiteit
AN ECOLOGICAL-ECONOMIC MODEL OF THE TROPICAL DRY FOREST ON THE
ISLAND OF BONAIRE
Dario Gerardo Zambrano Cortes
Pieter van Beukering1st Supervisor
Eliseos Papyrakis2nd Supervisor
Esther Wolfs External Supervisor
468017 (research project)
18 ects
MSc Environmental Resource Management
Institute of Environmental Studies
Vrije Universiteit Amsterdam
2012
ABSTRACT
This paper presents the first ecological economic model of tropical dry forest in Bonaire Island. The
model includes the main characteristics of the dry forest and interventions allowing scientists and
managers to evaluate ecological and economic impacts effectively. Two scenarios were compared in
order to derive conclusions about the management intervention. The baseline scenario assumes that
the current practices continue for the following thirty years while the alternative scenarios includes the
implementation of a birdwatching program, enhancement of agriculture, goat eradication and
husbandry and reforestation program. The study reveals that the investment on management programs
is preferred in most of the cases, bringing benefits of about $8.5 million overtime. The results also
suggest that is possible to have better ore equal benefits for both scenarios if the threats are reduced.
This would justify an investment on the eradication program since it is the most efficient program that
brings high revenues to most of the sectors.
TABLE OF CONTENT
1.
INTRODUCTION.................................................................................................................................... 1
2.
GENERAL APPROACH AND METHODOLOGY ........................................................................................ 4
3.
2.1.
The goods and services of Bonaire ecosystems .......................................................................... 4
2.2.
The simulation models and their Importance ............................................................................. 6
THE MODEL .......................................................................................................................................... 9
3.1.
Threats ...................................................................................................................................... 11
3.1.1. Tourism Module ...................................................................................................................... 11
3.1.1. Grazing module ........................................................................................................................ 13
3.2.
Ecological Description ............................................................................................................... 14
3.2.1. Land use Module ..................................................................................................................... 14
3.2.2. Ecological Module .................................................................................................................... 15
3.3.
Economic Description ............................................................................................................... 21
3.3.1. Pharmaceutical and Medicinal Value ...................................................................................... 21
3.3.2. Birdwatching Value .................................................................................................................. 23
3.3.3. Livestock And Agricultural Value ............................................................................................. 24
3.3.4. Recreation Value ...................................................................................................................... 26
3.3.5. Aesthetic Value ........................................................................................................................ 27
3.4.
The scenarios ............................................................................................................................ 27
3.4.1. Eradication of Goats and husbandry program ......................................................................... 29
3.4.2. Agricultural and Kunuku enhancement program .................................................................... 30
3.4.3.Reforestation program ............................................................................................................. 30
3.4.4. Birdwatching promotion .......................................................................................................... 31
4.
RESULTS ............................................................................................................................................. 32
4.1.
Scenario Analysis....................................................................................................................... 34
4.4.
The sensitivity analysis .............................................................................................................. 37
BOX 1.
The value of pollination and seed dispersal ......................................................................... 41
5.
DISCUSION ......................................................................................................................................... 42
6.
REFERENCES ....................................................................................................................................... 45
APPENDIX: THE VALUE OF POLLINATION AND SEED DISPERSAL ................................................................ 48
ABBREVIATIONS
CARMABI – Caribbean research& Management of Biodiversity
MEA -
Millenium Ecosystem Assessment
NPV -
Net Present Value
ROB. -
Ruimtelijk Ontwikkelingsplan Bonaire.
STINAPA - Stichting Nationale Parken Bonaire (STINAPA Bonaire)
TEEB – The Economics of Ecosystems and Biodiversity
TEV – Total Economic Value
WTP -
Willigness To Pay
1. INTRODUCTION
The dry forest is the most threatened tropical terrestrial ecosystem on earth (Quesada
et al 2009). A long history of grazing, felling and clearance for cultivation have already
destroyed approximately 66% of dry forest in Latin America (Quesada et al 2009).
Bonaire is not an exception. Trees were felled (in particular Haematoxylon brasiletto,
Zanthoxylum flavum and Guaiacum officinale) throughout Bonaire and Klein Bonaire
on 17th century and large grazers such as goats, sheep, donkeys, cattle and horses
were introduced and left to roam. Later in the 20th century, extensive deforestation for
the cultivation of Aloe and the urban expansion for tourist facilities was completed (De
Freitas et al 2005). Today, around 30.000 goats are roaming free on the island keeping
the ecosystem in a degraded state, most of the traditional gardens, Kunukus, a
traditional farming system are abandoned, agrarian industry is almost inconspicuous
and original ecosystems occupy less than 30% of the island, which is in a degraded
state (Figure 1).
Today, the consequences of the past decline and the current degradation of the dry
forest are starting to undermine the ecosystem services that the bonaireans rely on.
Water retention, local climate control, recreation services, pollination and water runoff
attenuation are affected. For instance, current reduction of vegetation and deficient
sewage system have caused a rise in nutrient loading in the freshwater runoff
increasing eutrophication on coral reefs and mortality of mangroves (Figure 2). These
early warnings show the gradual depletion and deterioration of these ecosystems
services. The decline of several crucial ecological functions of the terrestrial
ecosystems might have serious consequences for numerous economic activities and
thus would put the major source of income of the island at risk i.e. marine tourism.
There is general concern about the future plans for Bonaire. The local government is
working hard to preserve the natural and cultural heritage of the island but at the
same time there are plans to boost tourism, build new facilities, casinos, restaurants
and piers. Even though, it is not clear to what extent future plans are beneficial for the
island’s economy , current threats such as roaming goats and the growing overtourism
Beneficiario COLFUTURO 2010
may compromise on long term the marine and terrestrial goods and services that
Bonaire’s industry and culture rely on.
a)
b)
Figure 1. a) Location of Bonaire Island in the Caribbean sea.b) Water bodies (blue),
anthropogenic and agrarian area (gray) and remnant patches of dry forest (green)
based on the number of layers , diversity of plant species, relative scarcity and
number of rare species (De Freitas et al 2005).
In general terms islands are highly vulnerable to impacts and Bonaire is not the
exception. The small islands are highly vulnerable as their resources such as beaches,
coral reefs and mangroves. are often concentrated in small areas (Burke et al. 2004). In
terms of biodiversity it is well known that islands have a natural vulnerability to
extinctions which are accelerated mainly by habitat loss and invasive species
(Blackburn et al 2004, Traveset and Richardson 2006). Modest transformation
represents a threat on islands because scarce resources reach critical levels easily. For
example, in the Pattaya region of Southeast Asia, Coastal erosion was worsened due to
the combining effect of beach and water pollution that degraded the atoll (Wong,
1998).
Beneficiario COLFUTURO 2010
Figure 2. a) Dead mangrove at the back of LacBay due to filling of the inner lagoon with
sediments (Debrot et Al 2010). b) Plumes of sediment loaded water flowing in the sea
near Kralendijk after heavy rains(Borst & Haas 2005)
The following fifteen years, local government plans include the development of the
economy, tourism and social values on the island (ROB 2010). Increasing ecotourism,
rural tourism and at the same time conserving the landscape and cultural values of the
island becomes a challenge. The approved spatial plan of Bonaire (ROB) contemplates
the construction of households, highways and tourist facilities in order to boost the
economy (ROB 2010). However, to develop a sustainable economy, conservation of
forest and biodiversity must be taken into account. Inclusion of policies that increase
biodiversity will not only raise the value of the Bonairean socio-ecological landscapes,
but will ultimately ensure a sustainable economic development for future generations.
This project aims to evaluate the socio-economic interface between the ecological
processes of the tropical dry forest and the economic processes in the island of
Bonaire evaluating the consequences of land change on the This project is a tool for
scientists and managers to evaluate ecological and economic impacts effectively.
A dynamic simulation model is developed for this purpose. Additional to the model,
two scenarios were built in order to represent relevant management interventions for
the island.
Beneficiario COLFUTURO 2010
2. GENERAL APPROACH AND METHODOLOGY
Bonaire is a special municipality of The Netherlands located on the east part of the
Caribbean Sea. Bonaire is an island with a population of approximately 15,000
residents on a surface of 288 km2 (OLB, 2012). Most of its shoreline belongs to a
Marine Protected Area and the north-west constitutes the Washington-Slagbaai
National Park. As with other Caribbean nations, Bonaire relies strongly on tourism
activities, sector that contributes to one third of the island’s GDP (DEZA, 2008).
Recreation is not the only service provided by Bonairean ecosystems, both terrestrial
and aquatic environments provide a broad spectrum of services that tourists and locals
benefit from. Table 1 remarks how terrestrial ecosystems such as caves, the tropical
dry forest, mangroves and Kunukus are interlinked with the economy and culture of
Bonaireans and suggest the interdependency between the environmental quality and
the quality of the service.
2.1. THE GOODS AND SERVICES OF BONAIRE ECOSYSTEMS
Nature provides a wide range of benefits to people. For millennia, human beings have
benefited from some processes intrinsic to the functioning of ecosystems worldwide.
These ecosystems generate a range of goods and services that support human wellbeing and generate economic benefits, collectively called ecosystem services. The
Millennium Ecosystem Assessment (MEA, 2005) introduced the concept of ecosystem
services on the global agenda, recognizing four categories of services: supporting (e.g.
nutrient
cycling,
soil
formation
and
primary
production);
provisioning(e.g.food,freshwater,woodandfiberandfuel);regulating(e.g.climateregulati
on, flood and disease regulation and water purification); and cultural (aesthetic,
spiritual, educational and recreational).
Despite the fact that many people benefit from the ecosystem services, individuals or
groups usually have insufficient incentives to maintain the natural capital,
compromising ecosystems for continued provisioning of benefits (TEEB, 2010 ). The
flow from nature to humans is usually undervalued by governments, businesses and
Beneficiario COLFUTURO 2010
the public and only is considered once they have been lost. This link is often taken for
granted. Thus to put a monetary value on those environmental services and goods is
important in order to communicate its value in a comprehensive manner to all relevant
stakeholders. The economic valuation also plays an important role in incorporating the
ecological and socio-cultural values in decision-making processes.
Valuing ecosystem services provides an adequate assessment of the links between the
structures and functions of natural systems which helps to understand how
ecosystems provide services and how service provision translates into economic value.
Furthermore, it helps to incorporate ecosystem services on a daily basis facilitating the
analysis of trade-offs and synergies between different management options (NRC,
2005).
Although terrestrial attributes of Bonaire are not important in choosing holiday
destination (Uyarra et al 2005) and contribute in a small fraction to the total economic
value of the island, they are still important for stakeholders and relevant to decisionmaking. The valuation of terrestrial services is important because bird diversity and
landscape attractiveness contributes to the recreational value, playing an important
role in choosing holiday destination (Uyarra et al 2005). Moreover, how the terrestrial
ecosystem is managed has consequences on the marine environment through
sedimentation affecting the coral reefs and the main industry of the island.
In this study, the Economics of Ecosystems and Biodiversity framework (TEEB, 2010) is
followed in order to assess the terrestrial ecosystem services in Bonaire (Figure
3).Here, human decisions lead to actions, i.e. “drivers”, that impact ecosystems,
causing changes in ecosystem structure and function. These changes affect
provisioning, regulating, habitat and cultural services. Changes in ecosystem services
have impacts diminishing welfare, wellbeing and sustainability in the long-term.
Valuation of these changes or policy inaction, provides information that can engage
different stakeholders to influence human decisions that change the drivers and
ultimately, improve the state of ecosystems and the services they provide to society.
Beneficiario COLFUTURO 2010
Figure 3. The Economics of Ecosystems and Biodiversity Framework. (TEEB, 2010)
2.2. THE SIMULATION MODELS AND THEIR IMPORTANCE
The functioning of ecosystems, its delivery of services and the final contribution to
welfare is complex. To effectively evaluate the complex interface between ecological
and economic processes, simulation modeling can play a useful role representing the
main ecological functions and the interaction with the economic sectors. In
its
broadest sense, simulation is a tool to evaluate the performance of a system,
existing
or
proposed,
under
different configurations of interest and over
long periods of real time. The model quantifies changes on ecosystem services
provision and the output provides decision makers with information about costs,
benefits, trade-offs, synergies and opportunities.
There are several modeling techniques that allow a quantitative approach for the
evaluation of the network of ecological and economic interactions. Models can be
classified as deterministic when input and output variables are fixed values;
stochastic when at least one of the input or output variables is probabilistic; static
when time is not taken into account and dynamic when time variation is considered
(Carson & John 2004). In this assessment I develop a dynamic simulation model
because allows the evaluation of direct and indirect effects of policy intervention over
long time horizons. A dynamic simulation model may reflect the late changes due to
Beneficiario COLFUTURO 2010
the intervention and the intrinsic variation of the system throughout time. A
timeframe of 30 years (2012-2042) was used, adequate time for glance ecological
consequences, materialize interventions and provide a credible range of prediction
from an economic perspective.
Dynamic simulation models are widely used on the literature for different purposes.
They are also common in the assessment of ecological and socio-economic interactions
in marine systems like Bonaire. For instance, Nobre (et al 2009 2) build a model to
estimate the benefits and feedbacks between estuarine and coastal ecosystems with
the shellfish aquaculture in China. Van Beukering and Cesar H. (2004) evaluate the
effect of an environmental educational program on the value of the coral reefs in
Hawaii. Kandelaars (1997) evaluates the interactions between population, tourism and
environment in Yucatán to see the potential effects of policies and how certain
development paths can affect tourism and the environment on a regional scale.
Chiabai (et al, 2011) estimate the global economic loss of policy inaction due to the
loss forest’s ecosystem services.
Due to the limited ecological and economical information of Bonaire’s ecosystems
(Table 1), the valuation of this project focuses on the tropical dry forest. The total
economic value was calculated using the following values, Agricultural and Livestock
benefits, Recreational value, Birdwatching value, Aesthetic value, Medicinal and
Pharmaceutical value.
Extensive literature review and consulting the island experts, Wayaka Consulting and
Esther Wolfs1 was done to gather general and economic information of the island.
Occasionally I used value transfer from published studies, when specific information of
the island was not available. The simulations were done in STELLA software.
1
Director of WKICS BV and consultant for the project What’s Bonaire Nature Worth?
Beneficiario COLFUTURO 2010
Type of Service
Provisioning Services
Meat and milk from livestock
Food Provisioning
Natural Medicines
Regulating Services
Erosion Protection
Sediments Retention
Habitat Maintenance
Maintenance of Species
Cultural Services
Aesthetic Values
Support of Recreation
Birdwatching
Support of Cultural Identity
Educational and Scientific Information
Services
Table 1.The services of Bonaire’s terrestrial ecosystems
Explanation
Mangrove
Roaming sheep, goats and cattle feed on Bonaire’s
dry forest.
Cultivation of bananas, corn, aloe, among others
Supply of natural medicines
Maintenance of vegetation allows reduction of
erosion.
Avoidance of sediment discharges on the sea
affecting the coral reefs
Ecosystem
Dry Forest
Caves
x
x
x
x
Salinas
Kunukus
x
x
x
x
Species interactions such as pollination and seed
dispersal maintain the natural regeneration, the
biological and genetic diversity.
x
x
x
x
Bonaire’s landscapes provide scenic views for
relaxing and inspiration.
Supports hiking, horse riding and leisure activities.
x
x
x
x
x
x
Bonaire is home of unique and charismatic bird
species.
Supporting cultural activities, sense of identity.
Bonaire has unique plants and animals that give
opportunities for education, and scientific
research.
x
x
x
x
x
x
x
x
x
x
x
x
x
Non use values
Pharmaceutical Bioprospection
Beneficiario COLFUTURO 2010
Future pharmaceutical discoveries depend on the
plant richness on the island.
x
3. THE MODEL
A model may be described as a representation of the ecological-economical system
consisting in a reduced number of system elements, internal relationships
(endogenous variables) and interactions with the surrounding environment of the
system(exogenous variables). The model in this project represents the endogenous
variables as the relevant ecological and economic relations of the real system in
Bonaire.
It does not address exogenous variables such as world economy or
catastrophes that ultimately enhance the threats to the tropical dry forest.
The figure 4 highlights the key features of the model. The model consists of separate
modules representing economic and ecological characteristics of Bonaire and their
interaction. For instance it has a threat module that affects the forest condition and
consequently affects the extension of forest that provides economic benefits. The
model provides an evaluation tool for stakeholders by comparing counterfactual
scenarios that differ on specific actions and includes an intervention package that is
aimed to address the main threats.
The model consists in several steps. First, there are some threats such the goats and
the tourists that maintain or change the extension of different land categories and
some processes of the forest ecosystem. In the second step there are the land use
module and ecological module that describe the main ecological processes underlining
the regeneration of the forest and the land use change on Bonaire. The model
allocates land to four different land categories: Primary Forest, Degraded forest and
Agrarian and Urban. An extension of degraded Forest has the chance to become
Mature Forest by natural regeneration and this becomes degraded forest by grazing.
An extension of agrarian land can be transformed to degraded forest via
abandonment.
The third step, summarize the economic features of the model by describing the goods
and services from the forest by six modules: Agricultural and Livestock benefits,
Beneficiario COLFUTURO 2010
Recreational value, Birdwatching value, Aesthetic value, Medicinal and Pharmaceutical
value. Each of the goods and services, have associated economic benefits for Bonaire’s
society. The value of the sum of compatible uses of these goods and services forms the
Total Economic Value (Fourth step).
The fifth step are the management measures, the interventions aimed to change the
threats, the distribution of land, and the amount of the services provided by the forest
and land-use module. The management represents interventions such as goat
eradication and husbandry, the costs of reforestation, the cost of Kotuku’s
enhancement and the cost of promotion of birwatching events such as festivals,
publicity, contests, etc.
1: Threats
Grazing
2. Ecological
Description
Land use Module
3.Economic
Description
Recreational
Module
Livestock & Agricultural
Module
Tourism
Ecological Module
Pharmaceutical and
Medicinal Module
4. Economic
Valuation
Economic Benefits of
the dry Forest
5. Interventions
Land Management &
Interventions
Economic Benefits
6.Economic Effects
7. Evaluation
Aesthetic
Module
Birdwatching
Module
Financial costs
Net Present Value
Figure 4. General Framework of the dynamic simulation model
Finally, the final step of the model is the evaluation of the scenarios using the Net
Present Value (NPV) as the main evaluation tool. Here an analysis of cost and benefits
of the different combinations of the management options is presented. In this step the
Beneficiario COLFUTURO 2010
stakeholders make a final decision regarding which intervention or combination of
interventions is preferred comparing the alternatives and its benefit and costs.
The distribution of costs and benefits vary over time, therefore, they need to be
converted to NPV by discounting the values, in order to compare them during the
timeframe. Discounting is the practice of placing lower values on future benefits and
costs reflecting people’s preferences for the present rather than the future. The higher
the discount rate, the more valuable the future benefits. For the analysis a discount
rate of 5% was used, a common practice on environmental studies in the following
way:
NPV = ∑ t (B t– C t )·(1+r)-t
3.1. THREATS
3.1.1. TOURISM MODULE
Tourists may come to Bonaire by cruise ships or by plane. There have been
approximately 150.000 cruiser ship passengers on 2012 and 70.000 stay-over tourists.
Cruise tourists have shown a tremendous increase in the last years (Figure 5), due to
the new lines that are coming to the island. In contrast, stay over tourists has not
change significantly in the last years.
Even when tourism represents the biggest economical benefit of Bonaire, in general,
coastal and terrestrial tourism is associated with both positive and negative impacts.
Increase of the tourism industry carries a wide variety of development activities,
environmental impacts and coastal management problems that impact directly or
indirectly the ecosystems. For instance, conversion of abandoned land to agriculture,
housing and tourism facilities reduce the potential land for forest recovery, also, the
increase of human population stress the fauna (see section 3.2.2.). Moreover an
increase in resorts could affect aesthetic values affecting the resort arrivals.
Construction of facilities could block ocean views and excess amounts of tourists may
reduce cultural attributes of the island when beaches are crowded (Lacle 2011).
Beneficiario COLFUTURO 2010
Figure 5. Tourism trends on Bonaire for the last years (Bonaire tourism Agency).
In the module (Figure 6), the annual rate of terrestrial tourists depends on the quality
of the forest represented by the “Forest State Indicator” that ranges from 0 to 1(see
section 3.2.2.). Then the growth rate of tourism will have a minimum when the
indicator is 0 and a maximum when the indicator is 1. I estimated from the information
of the period 2007-2010 (figure 5) that the growth of rate of cruisers will have a range
from -0.024 to 0.57. In the same way the estimated range of the rate of stay over
tourists will be from -0.09 to 0.19.
To represent the possible effect of overtourism disturbing local fauna the module
includes the “Disturbance” parameter. The parameter is the sum of the population and
tourists each year, ranging from 0 to 650000, the double of current state. To see how
this parameter is linked to the ecological module, please refer to section 3.2.2.
Figure 6. Tourism module, depicting the human disturbance model
Beneficiario COLFUTURO 2010
3.1.1. GRAZING MODULE
Roaming goats, donkeys and sheep are the main threat to the Bonairean ecosystem
services. Around 30,000 goats, 300 donkeys, and 10,000 sheep roam free around the
whole island including the Washington-Slagbaai National Park (Esther wolfs, pers.
com.) Since three centuries ago the presence of heavy grazing has stopped the
regeneration capacity of the forest, leaving a low plant richness ecosystem dominated
by thorny and grazing-resistant species (De Freitas, et al 2005).
Invasive species on island constitutes one of the main threats to biodiversity
worldwide. Introduced herbivores such as donkeys, sheep and goats eliminate grazing
sensitive species and the competitive release of grazing tolerant species. Succession to
mature forest is reduced due to the lack of seedlings and decrease of species diversity
by making predominant weedy unpalatable species such as Aristida, Opuntia, and
Acacia. These invasive species convert the forest to bare ground or grasslands and
accelerating soil erosion (Debrot and Freitas , 1993).
I modeled the population of donkeys, goats and sheep as constant assuming that the
population dynamics behave as a steady state where the number of births and deaths
(either by slaughter either by natural death) are equal. Any management intervention
will reduce this amount.
The grazing intensity on the island was modeled in the following way (Figure 7). The
number of sheep, goats and donkeys are converted to Tropical Livestock Units (TLU) a
common unit of agrarian production. One TLU equals to 1.5 cattle head, I0 sheep, 12
goats, 2 donkeys or 1 horse and requires 2,300 kg of annual dry mass (Le Houerou and
Housted, 1977). Taking into account the grazers population mentioned before and the
TLU equivalences, I estimated that current grazing pressure on Bonaire in 4,133
TLU/year.
I estimated the carrying capacity of the island using its annual rainfall and the
procedure described by Le Herou and Housted (1977). With 495 mm annual rainfall,
the carrying capacity of the island is 0.197TLU/ha.year. Using the total terrestrial area
Beneficiario COLFUTURO 2010
of the island (see 3.2.1.) the carrying capacity for grazing would be 5,535 TLU/year.
However, considering that the capacity of Bonaire’s soil to support careful grazing is
limited to 8,350 ha (Panagos et al 2011), the grazing capacity of the island is only
1,645 TLU, meaning that the current grazing activity surpass by 2.5 times the capacity
of the island.
Figure 7. The Grazing Module and its components.
3.2. ECOLOGICAL DESCRIPTION
3.2.1. LAND USE MODULE
Considering that spatial information regarding land uses and ecosystems is scarce, it
was necessary to make some assumption in order to establish a congruent allocation
of land for the project. For instance, what the Land Management Plan of Bonaire (ROB,
2010) states as nature, De Freitas (et al 2005) categorized it as both agrarian and
nature and experts assumed to be agrarian land. The Table 3 lists the information
about land uses available in the literature.
The Figure 1B depicts the allocation of land according with De Freitas (et al 2005)
showing in gray the Anthropogenic land and in green “the patches with highest
conservation value” that constitute around 5000 ha and correspond to the so called
“Mature forest” in the model.
Beneficiario COLFUTURO 2010
Table 3. Land allocation for this project and
according with different sources
Total Area (ha)
28100*/30200+
Terrestrial Area (ha)
21100*
Water Bodies (ha)
7000*
Anthropogenic (ha)
4231*
Mature Forest(ha)
5000*(estimated)
Degraded Forest (ha)
16869*(estimated)
Agrarian Land(ha)
7000‡
Limited Grazing Area (ha)
8350+
*De Freitas et al (2005), + Panagos (et al 2011),
‡Esther Wolfs (per.com.2012)
According with De Freitas (et al 2005) there is little remains of a mature forest on
Bonaire because the extremely degraded state and the unknown composition of the
flora before colonial times. Different vegetation types are mentioned on the same
publication suggesting the existence of at least two different types of ecosystems not
taken into account before: the dry evergreen formations and seasonal dry forest. For
practical terms and lack of information, I refer to tropical dry forest both typologies.
In the model there are three types of land use, Mature Forest, Degraded Forest and
Agrarian Land. An amount of 21100 ha is allocated between the three categories so
the lost of area in one type represents the increase on the other types of land. For this
project an amount of 21100 ha was assigned to the total terrestrial land categories,
5000ha corresponding to the Mature forest, 7000 ha of agrarian land and the
remaining for degraded forest category. In the model, the Degraded Forest becomes
Mature Forest by natural regeneration and this becomes degraded forest by grazing
(see 3.2.2.). Agrarian land can be transformed to degraded forest via abandonment.
3.2.2. ECOLOGICAL M ODULE
Little is known about the tropical dry forest ecology and general information about it is
rare. Studies of abandoned lands have shown that the tropical dry forest regenerates
fast, reaching a maximum of basal area of 25m2 per ha and the maximum of 25 species
per plot between 30 and 40 years(Figure 8). Apparently, coppicing from stumps and
roots remaining after disturbance is considered as the primary regeneration
mechanism of disturbed tropical dry sites. Contributing to this regeneration takes less
time to reach maturity (Quesada et al 2009).
Beneficiario COLFUTURO 2010
Seed dispersal by wind is also important for regeneration. The pioneer species within
abandoned lands are wind dispersers plants like the Yellow Poui and Kapok, that work
as nursery trees for other species (Aide et al 2000) accelerating the transition to
primary forest.
Figure 8. Recovery of the tropical dry forest with the age of abandonment using two
indicators: basal area (left) and number of species (right)(from Aide et al 2000)
Plant-animal interactions in the tropical dry forest are extremely important for
conserving the plants, animals and genetic diversity of the forest. It is estimated that
54–80% of the STDF plant species rely on animal vectors for its pollination, such as bats
and the hummingbirds (Machado and Lopes, 2004). This interaction is crucial for the
cacti Kadushi, Agave, Kalbas and Kapok which are important diets for the
aforementioned animals.
Seed dispersal by birds and bats is also important. Animal dispersed species in the dry
forest are estimated between 43%-64% of the plant species within the forest (Quesada
et al 2009).Changes in animal communities during succession undoubtedly affect seeds
arriving to areas undergoing succession and ultimately the emerging succession of the
forest, making seed dispersal important for plants such as the medicinal tree Wayaká
and the Cactus Kadushi. Further absence of such interactions may trigger a cascading
effect, affecting plant density and reducing pollination (Traveset and Richardson 2006,
Anderson et al 2011).
Beneficiario COLFUTURO 2010
Figure 9. Ecological module
The table 4. List the number of birds, bats and plant species on Bonaire showing the
differences between the species found and the approximately current state. Bonaire
has no endemic birds or bats but a couple of snails and lizard species (Wells and
Debrot, 2008, STINAPA 2012). Many of Bonaire’s birds are geographically restricted or
threatened of extinction on the nearby area. For example, the Caribbean Coot and the
Bare-Eye Pigeon are only present in the northern part of Venezuela and the Lesser
Antilles.
Only 55 bird species are residents while around 60 are migrants and occasionally found
(Wells and Debrot, 2008). My estimation is that around 40% of the species on Bonaire
are coastal birds therefore their reliance on terrestrial ecosystems is unclear.
Regarding the bats, there are only eight species registered on the island though five
are frequently seen and 75% of cave-dwelling bat species on Bonaire have less than
500 individuals (STINAPA, 2012). As the animal species, plant species composition
resembles the flora of the Caribbean region. The flora consist of 387 vascular species
including 36 introduced and naturalized species having only one endemic plant species
(De Freitas, et al 2005).
Table 4. Number of Species in Bonaire for different groups.
Beneficiario COLFUTURO 2010
Registered Species
Frequently found
Birds
210
<100
Bats
8
5
Plants
351
160
The ecological module aims to reflect the mentioned ecological characteristics of the
tropical dry forest including a fast regeneration, early maturity, and facilitated
regeneration by seed dispersal and pollination by bats and birds. The figure 9 depicts
the general structure of the model, in the following text I will explain parameters and
the assumptions used.
Considering the mentioned generalizations about the regeneration of the dry forest I
assumed an annual regeneration rate of 1% of the forested area per year. This 1%
sounds arbitrary, but it approximated the regeneration rates of figure 8. Taking into
account the importance of the regeneration rate parameter for the model, a sensitivity
analysis is applied on further sections in order to evaluate the reliability of the
assumption.
I reflected the importance of plant-animal interactions on the model including the
parameter “facilitated regeneration”. I estimated it as 1%/year considering that not all
pollinated flowers become a viable seed and not all seeds are becoming trees, but still
determine regeneration dynamics. This additional regeneration is available on the
model when there is a high animal richness.
It is very difficult to make generalizations about how birds and bats abundance and
richness might be influenced by forest cover and human disturbances. This is because
different guilds and species respond differently (Lasky & Keit, 2010, see Chettri et al
2000 and Trzcinski et al 1999). For example, abundance of insectivorous birds is
favored by low forest cover but in contrast cavity-nester birds such as the Lora are very
limited by availability of tree holes. This is essential for their reproduction but only
available in mature forests as seen with other parrots (Cockle et al 2010, Lasky & Keit,
2010).
The “Animal richness” parameter attempts to reflect the response of the fauna to the
mature forest cover. The general idea is that more mature forest extension correlates
Beneficiario COLFUTURO 2010
with more species of birds and bats. I assumed a linear function (Figure 10) with a
maximum of 60 species, considering the current state evaluation made before and lack
of information about how many species of birds are found on Bonaire’s forest in a
particular period of time.
Figure 10. Animal richness in function of the mature forest extension.
The disturbance function is also difficult to determine; there is no doses-response
research to tell us how affected are the animals when different sizes of crowds of
tourists approach. Furthermore, the impact of tourists varies in different systems
depending on the resilience of the attraction after disturbance. For example, recovery
from visitor impacts, might be relatively quick for tracks in some forest compared to
the more sustained and permanent alterations of visitor impacts in low energy cave
ecosystems (Cigna, 1993).
Disturbance may be caused by habitat alteration when crowds of people approach
feeding and nesting grounds. There is evidence that tourist disturbances can increase
nest abandonment and increase bird stress, reducing the successful reproduction,
foraging and reducing the frequency of sight (Rochelle et al 2011, Fernandez 2000,
Velando & Munilla 2011).
An “Animal Occurrence “ function was included on the model in order to reflect the
effect of tourism and disturbances on the abundance of birds. Occurrence is an
independent parameter that refers how often a bird is sighted regardless the species.
Unfortunately the lack of ornithological surveys leaves us to make raw assumptions
Beneficiario COLFUTURO 2010
about the number of individuals per species of birds and bats found in a period of
time.
Considering the current state evaluation made on before and the discussed limitations
I assumed a linear function (Figure 11) which maximum is 80 species. I assumed a
minimum of species is 1 when “Disturbance” is 650000 people/year and maximum of
species of 80 when the disturbance halves the current state.
Figure 11. Animal occurrence in function of the disturbance.
In order to represent the threat of grazing on the plant richness I included a function
that when grazing is bigger than Bonaire’s carrying capacity the plant richness drops to
160 species.
Together, plant richness, animal occurrence and richness, constitute the “Forest state
Indicator”
a general indicator that summarizes the quality of the forest and influences
the arrival of tourists (see section 3.1.1.). The indicator ranges from 0 (low quality) to
1(high quality). All three components of the “Forest state Indicator” are normalized in
order to sum all of them, which means, for each of the functions the minimum is
converted to 0 and the maximum to 1.
In order to show how different environmental attributes influences in different ways
the environmental quality and hence, the “Forest state Indicator”, a weight was applied to
each normalized value. I assumed that animal diversity affects most the “Forest state
Indicator”
and applied a weight of 0.6 to animal richness and 0.30 to tourism
disturbance, considering that animal diversity is more influenced by habitat
destruction than disturbance by tourists (Kangas et al, 2010). A weight of 0.10 was
Beneficiario COLFUTURO 2010
applied to plant richness considering that landscape’s attractiveness on Bonaire plays a
moderate role determining the choice of holiday’s destination and that higher plant
diversity is not perceived by the public as a higher environmental attribute (Uyarra et
al 2005, Jacobson 2009).
3.3. ECONOMIC DESCRIPTION
3.3.1. PHARMACEUTICAL AND MEDICINAL VALUE
Plant diversity has always had an important place in medicinal and alimentary use
worldwide. For example, it has been seen that places with a higher plant diversity
correlates with more diverse diets and medicinal uses constituting an important
component for food security and health(Pearce, 2001). Plant diversity contribute to
social welfare in different ways: providing a cultural identity for local communities and
providing natural medicines for local use and phytochemicals-compounds used by
pharmaceutical companies’ research against diseases such as cancer (Simpson et al
1996).
From a recent study the 67% of the people use of plants to treat physical complaints
like headache, fever, stomach ache reuma, among others (Lacle 2011). Many of these
plants come from the dry forest but also they are non native species. Besides there is
not a large market for these plants the value of plant diversity for medicinal use and
pharmaceutical research still exists and can be value as direct use values and future
use values.
The direct use value of the medicinal plants of Bonaire will be calculated through
annual opportunity costs since no local medicinal market exists (Figure 12). The value
is calculated by the money saved in doctor’s visits and the money saved in buying
modern medicines each year.
Whereas Bonaireans do not have to pay for a doctor's consultation since the
constitutional change of the value is nevertheless still existent, and paid by the
government. The costs of a visit were estimated at $20,which corresponds to the price
Beneficiario COLFUTURO 2010
before the constitutional change. Following the approach by Brock et al (2011) the
value below indicates the reduction of doctor’s visits.
Y = $ * frq * pop * users * red
Where $ is 20 dollars, the cost of a doctor’s visit, frq is 2.4 the average number of
doctors visits for a family of 5 members, pop is Bonaire population in each year (see
section 3.1.),users is 67%, the percentage of medicinal plant users (Lacle 2011) and red
25% the assumed reduction of doctor’s visits.
The amount of money saved from spending on modern medicine is calculated in the
following manner:
Y = $/med * pop * users * red
Where $/med is 180, the average of money spent on medicine adjusted to the island
income, pop the number of users as above, red 50%, the assumed reduction of
medicine purchase.
For valuing the pharmaceutical use I used the pharmaceutical companies’ willingness
to pay per hectare, reviewed by Pearce (2001). This document reviews three different
methodologies for valuing pharmaceutical value of several biodiversity hotspots.. For
the different places the values ranges from 0.2-20.6 USD/ha, from 2,9-2,888 USD/ha in
an intermediate estimation and a 0-9177 USD/ha for a high estimation methodology. I
took the estimation made for Madagascar of $6.9/ha since the climatic conditions
there are similar to Bonaire.
Figure 12. Medicinal and Pharmaceutical value module.
Beneficiario COLFUTURO 2010
3.3.2. BIRDWATCHING VALUE
Birdwatching tourism worldwide appears to be growing rapidly and has attracted
attention in recent years in many places, especially in protected areas, as an
apparently environmentally-friendly way of enhancing local economies and protecting
the environment (Kim et al 2010, Connell, 2009). Although this trend, an insufficient
recognition is given to the legitimacy of birdwatching as a promotional tool mainly
associated with the idea that birdwatching is for specialized users. A recent study in
Queensland reveals that highly specialized birdwatchers compromise only 5-10% of the
market, giving space within markets for inexperienced birdwatchers through the
guided tours and tourist packages (Kim et al 2010).In United States, wildlife watching
generates $32 billion in that country alone and between $8-12 million is spent by
tourists annually in order to see the White-Tailed Eagles on the Isle of Mull (UN-News,
2012)
Despite Bonaire does not have any endemic bird species, we have to take into account
that the Caribbean region is a hotspot biodiversity of birds and a corridor for migratory
birds. Birdwatching might enhance biodiversity and heritage values contributing to the
sustainability of island society, the economy, and the conservation of its fauna and
flora as already happened on the islands of Kapiti and Fair Isle where bird tourism has
enabled an extended tourist season, becoming a considerable proportion of local
income when other forms of tourism have declined or stagnated (Connell, 2009).
There is a huge potential for expansion of birdwatching in places with both diversity
and endemism such as Bonaire since there is relatively little contemporary
birdwatching tourism. Moreover bird diversity and different activities involving birds
constitute a major component of visitor’s satisfaction and contribute to revisit an
ecolodge (Tisdell and Wilson 2003). For instance, the geographic restriction of bird
fauna might be an attraction for specialized birdwatchers interested in rare species.
Also, migratory season coincides with the low season of April/May and
September/October, providing opportunities for new tourism packages.
A potential market with general birdwatchers is also possible, including physical
contact, sight contests, feeding events, good interpretation support and other tourism
facilities (Tisdell and Wilson 2004).
Beneficiario COLFUTURO 2010
The general structure of the model for the annual valuation of the Birwatching value is
shown in figure 13.
From the tourists coming to the island just a small percentage involve in birdwatching.
There is no information about how much people involve on birdwatching but
nowadays it is considered almost inexistent (Esther Wolfs personal communication).
My raw assumption is 0.1%.
Each birdwatcher pays a tour of about $50 per person where, in average, 25 species
are visible (estimated from the field records on http://www.bonairebirds.com/). I
assumed that additional income is generated with increased bird biodiversity. Lee et al
(2010) estimate the willingness to pay (WTP) for additional diversity in $12.64 per
person. This additional diversity may include watching rare species, flocks of migrating
birds, among others. I modeled it as an additional benefit when the “Animal richness”
parameter is more than 25 species.
Figure 13. Birdwatching value module.
3.3.3. LIVESTOCK AND AGRICULTURAL VALUE
Not only goats are raised on Bonaire but sheep, pigs and cows are common sources of
income and food. Goats are especially part of Bonaire’s culture and are the main
component of many dishes.
The traditional goat production on Bonaire is carried out through the free roaming of a
variable source of plant species with a wide spectrum of nutritional value. Low
economic and technological input, low efficiency on the management of pastures and
Beneficiario COLFUTURO 2010
animals and low water use and fertilization, characterize the goat management (Van
Beuzowen et al 2009). The low fertility of soils make Bonaire soils unsuitable for
extensive grazing and in long term degrade them with an increase of undesirable
plants, unpalatable and toxic for the animals making them ill and producing abortions
(Nouel y Rincón, 2005). This factor explain the low productivity (~10Kg) of the goat
herds, the productive system on Bonaire hamper the meat sector itself and the other
sectors on the island, producing low weight gains on the animals and affecting native
species and ecosystems (Garcia, 2005).
Agriculture on Bonaire takes place on the Kunukus, around 300 of them still remaining
on the island, producing bananas, corn and fruits such as the papaya. Production
supplies in a limited way the local consumption, but still relies on imports. Agriculture
also has a low production with the same limiting factors as the goat production. Low
economic input, non use of water management, low efficiency of soil, erosion and loss
of nutrients. The only evidence of intensive agriculture on Bonaire was Aloe around 50
years ago, today the crops are not intensively managed and some of them are
abandoned (Van Beuzowen et al 2009).
There is little information about livestock production and agriculture on Bonaire. The
table 5 shows the different types of animals that arrive to the slaughter house in
Bonaire. With a total of 2487 animals, it is estimated that the same amount of animals
are killed in the private properties for local consumption or commercialization. Each
kilogram has a price of $5.6 per Kg with no difference on prices among the types of
meat. Regarding agriculture, there are estimates that the local production of
household vegetables and fruit is circa 10.000 USD per year for around 7000 ha
(pers.com. Esther Wolfs, 2012).
Table 5. Arrivals to the slaughter House in 2011*
Type
Number
Kg
Goat
1910
18,630.74
Sheep
577
5830.58
Pig
155
6932.12
Cow
4
*Esther Wolfs pers. Com. 2012)
Beneficiario COLFUTURO 2010
862.05
The structure of the module is pretty straightforward. The Agricultural profit depends
on the amount of agricultural land allocated on the land use module. As a basis
$1.4/ha.year is the revenue modeled on this module.
I limited the estimation of the annual value of livestock as the amount of meat of
sheep and goats sold. An average of 5.6 Kg of meat per animal is used and 4,974
kills/year in order to reflect the legal and illegal kills. The price per kg of meat is
maintained constant throughout the 30 years of simulation.
3.3.4. RECREATION VALUE
Besides the aquatic recreation is the major contribution for the economy of the island,
the tropical dry forest provides several opportunities for recreation on Bonaire.
Around 40.000 visitors enter to the Washington Slagbaai National park and several
participate on recreational activities along the year, including walking, hiking,
birdwatching, biking and cycling (Table 6.). Most popular activities are “Walking”,
“Cycling” and “BBQ/Camping” while the most common places to practice them are the
Washington Slagbaai Park, Rincon, Lagoen and Seru Largu but the Kunukus as well.
These activities are done mainly by tourist but in general a person who was born on
Bonaire participates significantly less in recreational activities (Lacle 2011).
Table 6.
BBQ/Camping
Walking
Hiking
Cycling
Hunting
Frequency of recreational on Bonaire (Lacle, 2011)
Never 1-6 Times a year
7-12 times a More than once
year
a month
66%
21%
2%
9%
35%
20%
5%
15%
80%
9%
2%
6%
81%
5%
1%
5%
94%
2%
1%
3%
More than
once a week
2%
25%
3%
8%
0%
The value of recreation was calculated annually based on the incoming tourists per
year. A fraction of 1% of the visitors to the island is considered to be involved on
terrestrial activities. The estimation of the value of recreation on Bonaire was
completed through the different costs: $20 for renting a bike, $50 attending a guided
tour or caving and $10 for entering the national park. I assumed that all the terrestrial
tourists do these activities at least once per visit.
Beneficiario COLFUTURO 2010
3.3.5. AESTHETIC VALUE
The aesthetic values of the ecosystems are part of nonmaterial benefits that people
obtain through spiritual enrichment, cognitive development, reflection and aesthetic
experiences. Many people find beauty or aesthetic value in various aspects of
ecosystems, as reflected in the support for parks, scenic drives, and the selection of
housing locations and enjoyment of scenery. The view of a clean forest without dusty
clouds is perceived as a benefit to those that can enjoy it every day and a human
health benefit.
The calculation of the aesthetic value is based on the changes of the WTP for
terrestrial quality changes according with the “Forest State Indicator”. The values of
the WTP of Bonaire residents for environmental quality are obtained from Lacle
(2011). Here, the monthly willingness to pay for a transition from low terrestrial
quality to high terrestrial quality is $9.07 U.S. dollars per person/month while the
transition from a poor to a medium quality $5.55 person/month.
The change on the WTP follows a linear function (Figure 14) according with the
aforementioned values. Each year the WTP is multiplied by the population of Bonaire
and transformed to a year basis in order to express the annual aesthetic value.
Figure 14. Resident’s WTP for environmental quality in function of the “Forest
state indicator”.
3.4. THE SCENARIOS
In order to make sound policy decisions with regard to environmental problems,
decision makers need information on the benefits and costs of alternative options. The
use of scenarios is important to stakeholders in order to identify critical management
Beneficiario COLFUTURO 2010
decisions. The scenarios might forecast the provision of services in response to the
interventions and describe plausible futures, combining alternative decisions with
projected changes in demographics, climate, economic crisis and other factors.
The following scenarios try to include relevant questions that policy makers and
stakeholders might ask in order to show the applicability of the model. The table 2
summarizes the measurements but they are described in detail on the following
sections.
Table 2. Parameters used on the different scenarios
Baseline
Alternative
Degraded Forest( ha)
14000
17000
Goats
30000
20000
Percentage of birdwatchers
0.1%
Increase up to 10% in 30 years
Urban and Agrarian (ha)
7000
4000
Grazing and Livestock Pressure
yes
no
Profit Goat (kg/animal)
10
20
Profit Agriculture ($/ha)
1.42
2.84
Restoration (ha/year)
0
33
The baseline scenario represents the policy inaction effects on the economic value of
terrestrial ecosystems on Bonaire. Here the 30,000 goats are roaming free as today
and the economy remains relying on the tourism. In the other hand, the alternative
scenario includes a package of four programs: Goat Eradication and husbandry,
agricultural, reforestation and a birdwatching promotion.
The alternative scenario represents the simultaneous implementation of the four
programs. Here, the eradication of 10,000 goats and fencing of other 20,000 goats.
Here the goat industry doubles its profits due to technical improvement by a goat
husbandry program and technical forage production. In the alternative scenario the
reforestation of the national park is extending the mature forest 33 ha per year,
greening the island in 4% during the 30 years.
Reactivating the Kunukus enhances local agriculture, goat husbandry and water
harvesting without reducing the forest area and increasing the productivity per
Beneficiario COLFUTURO 2010
hectare. The promotion of the island as an eco-touristic destination is used in this
scenario. Here the increase of ecotourism activities on the packages includes
birdwatching, hiking and speleology that increase tourists’ inflow.
3.4.1. ERADICATION OF GOATS AND HUSBANDRY PROGRAM
The program of eradication of goats contemplates the extermination of 10000
individuals inside the Washington Slagbaai Park during five years, that is, 2000 goats
per year, bringing additional revenues of $110000/year by selling the meat of the
eradicated goats. The costs of goat eradication were estimated according with the
expenses of goat eradication at Santiago Island, Galapagos Islands and Ecuador for the
period of 2001-2006 (Cruz et al 2009).
In the Galapagos’ program different methods were used, for instance, aerial and
ground hunting with dogs with different techniques, Judas goats2 and sterilization. The
cost an efficiency of each method differs significantly, basic techniques, such as ground
hunting, have an average success of 0.89goats/hour while the sophisticated ones like
aerial hunting may have an efficiency of 41 goats/hour. Costs may vary as well, ranging
from $24 per goat for corral hunting (corralling goats in the highlands during dry
months) to $744 per goat when the Judas goat method was used followed by a
monitoring program.
The eradication program in the model runs for 5 years, the same timeframe of the
project at Santiago Island, Galapagos Islands. The average of all the eradication
methods costs ($77/per goat) is used in the model in order to reflect the approximated
costs of the eradication. Considering that each technique has its advantages and
disadvantages it becomes an opportunity for efficient investment, the information
about what technique to choose is led to the decision makers. Cruz et al 2009 has a
concise summary of the cost per goat and the efficiency of each method.
As mentioned before on section 3.5.1. the goat program includes the control of
roaming goats and the goat husbandry program. A goat husbandry program may
2
Judas goats :a system of extermination which applies a georeferencing device to an animal. When it
goes back to the herd, reveals the position of the group facilitating the eradication.
Beneficiario COLFUTURO 2010
include programmed diet, confinement of the herds and use of special technique for
the production of forage. It could increase the productivity per animal up to 5 times
even in dry season and results may be evident after one year of implementation
(Garcia, 2005).
In the model the alternative scenario doubles the production of meat per animal
slaughtered. The eradication of goats in the National Park gives additional benefits for
the husbandry program when each of the goats eradicated is sold as consumable meat
on the local market
The cost of the goat husbandry program is estimated on $40,000 per year based on the
cost of a Haitian project which includes technical support and monthly workshops
during five years (GBGM, 2012) starting on 2017. This will educate approximately 300
goat keepers on better practices that at the end, will bring higher revenues for each
farmer.
3.4.2. AGRICULTURAL AND KUNUKU ENHANCEMENT PROGRAM
Currently, an area estimated of 7,000 ha is designated to low productive agriculture or
abandoned fields. Future plans for enhancing production of food for goats and
residents will focus on 4,000 ha (Esther Wolf, 2012 pers. Comm.). In the simulations
the implementation of the agricultural program will double the productivity per
hectare while the remaining 3000 ha would become tropical dry forest.
The program will cost between $9-12 million during the five years of the project (MIM,
2012). The average of $10.5 million used in the model during 2012-2017. The costs
include reactivation of the 375 Kunuku’s, the development of communication strategy,
implementation of waste management, education and recycling programs,
3.4.3.REFORESTATION PROGRAM
The interventions contemplated for the forest include the increase of area of forest
due to the abandonment of 3000 ha from the agricultural project. The program
includes a restoration program inside the Washington Slagbaai Park that requires the
reforestation of 33 ha per year during the 30 years time frame. The costs of restoration
of dry forest were transferred from the projects in Puerto Rico by the U.S. Fish and
Beneficiario COLFUTURO 2010
wildlife services. The cost of restoration is between $1,750-3,000 per hectare. I used in
the model the average of this range ($2375/ha) (FSW, 2012).
3.4.4. BIRDWATCHING PROMOTION
When the birdwatching program is implemented the percentage of birders will
increase during the 30 years of simulation. In the model the percentage of birders is a
positive linear function from 0.1% and up to 10% on the year 30.
The increase of birdwatchers is achieved through the active promotion by festivals,
publicity, events, etc. The program is estimated to cost about $50,000 per year,
considering the average cost of an annual project completed by STINAPA.
Beneficiario COLFUTURO 2010
4.
RESULTS
The main goal of the formulation of both scenarios was to determine the value of Bonaire’s
dry forest and evaluate the effectiveness of the intervention programs. The scenarios
include relevant questions that policy makers and stakeholders may ask and show the
general behavior and applicability of the model.
The figure 15 shows the allocation of land uses for the baseline scenario showing the
consequences for policy inaction for the simulated years. The sudden change is expected
because a fast degradation was modeled in agreement with the high grazing pressure
found on section 3.1.1.
Figure 15. The Land uses allocation for the baseline scenario
The allocation of land in the alternative scenario, where some programs were applied in
order to reduce the impact of threats to Bonaire, is shown on Figure 15. In the alternative
scenario focusing on 4000 ha of agriculture (see section 3.5.2) leaves 3000 ha that
gradually becomes degraded forest. Progressively, this new land on the degraded forest
category becomes mature forest. At year 30 both mature and degraded forest share about
the same extension but mature forest does not reach its maximum in this timeframe.
Beneficiario COLFUTURO 2010
The figure 16 shows the trends of the “Forest State indicator” during the simulated time
for both scenarios. As expected the baseline scenario maintains stable because there are
no intervention measurements to improve the forest. Just minor declines are seen at the
beginning and the end of the simulation period. In contrast in the alternative scenario, the
environmental quality rises gradually from 0.3 but does not change considerably. It is
important to remark that that 0.3 is the estimated quality of Bonaire based on the
assumptions made on chapter 4.5. No real environmental assessment of Bonaire has been
made up to date that includes animal occurrence, richness and plant diversity.
Figure 16. The Forest State Indicator during time
There are no differences between the population and tourists’ number for both scenarios
(Figure 17). Mainly this is attributed that the changes on the “Forest State indicator” were
not enough to reflect changes on the numbers.
Figure 17. Increase of population and tourists for the baseline scenario and the
alternative scenario.
Beneficiario COLFUTURO 2010
4.1. SCENARIO ANALYSIS
The figure 18 shows the annual economic benefits of the dry forest in Bonaire for the
baseline scenario. Each color represents the benefits for each of the six values described on
chapter 4 without discounting. The Medicinal and Pharmaceutical Value and Aesthetic
value are the only two categories that keep increasing in time because the increasing
population. In contrast, the recreation keeps constant benefits of about $240000/year
because the tourists do not change over time. Birdwatching and Agriculture maintain
constant benefits of about $15000 and $10000 per year respectively.
Figure 18. Annual benefits of the dry forest on the baseline scenario
The figure 19 depicts the annual economic benefits of the dry forest in Bonaire for the
alternative scenario. Each color represents the benefits for each of the six values described
in previous sections without discounting. Most of these costs are distributed during the
first five years when the intervention programs such as the goat husbandry, reforestation
and agriculture programs start to be implemented.
Figure 19. Annual benefits of the dry forest for the alternative scenario
Beneficiario COLFUTURO 2010
As expected Aesthetic, Livestock and Birdwatching benefits are higher than the values on
the baseline scenario because of the intervention. The Recreation, medicinal and
pharmaceutical benefits remains the same or increase slightly compared with the baseline
scenario because there is no increase in population and tourists. The abrupt changes on
livestock benefits are possible and realistic because there are extra benefits of about
$200000 for the meat sold from the eradicated goats. In addition, the results of the goat
husbandry program could be seen after one year of implementation.
Figure 20. Implementation of the individual intervention programs (Green) and in combination (Blue).
Benefits and costs are discounted with a 5% discount rate and 30 years of timeframe..
The figure 20 depicts the NPV when the goat, agriculture, reforestation and birdwatching
programs are implemented. The figure contrasts the effect of the individual programs,
different combinations and the alternative scenario, that is, the effect of the simultaneous
implementation of the four programs.
The goat program provides the highest net benefits as a single program or where is present
in combination with other programs. Surprisingly the alternative scenario is not the best
option, and it is attributed to the high cost of the agriculture program that significantly
diminishes the benefits. Only the goat program provides a synergist effect to the NPV,
giving additional benefits that are not available with the implementation of single
programs. For instance, the combination of the goat program and the reforestation
program provide the highest NPV, value that is not reached with the implementation of
Beneficiario COLFUTURO 2010
both programs alone. The NPV of the arrangements where the goat program is not present
is limited to the aggregation of the NPV of the combined programs.
The net present value of the intervention scenario is $8.9 million, with discounted net
benefits of $45.2 while the costs of implementation of the alternative scenario ascend to
$13 millions. The discounted net benefits of the baseline scenario are $36.3 million.
The major contribution to the benefits (Figure 21) is provided by the aesthetic and
pharmaceutical value while Birdwatching becomes an important contributor in the
alternative scenario. The goat eradication program is the only one that improves more than
one value increasing the aesthetic, medicinal and pharmaceutical value. As expected the
Livestock program doubles in the alternative scenario, the “Pharmaceutical and medicinal”
value increases scarce $700000 and the recreation value did not increase at all because the
number of tourists did not.
Figure 21. Contribution of the scenarios to the improvement of the evaluated values. Benefits discounted with
a 5% discount rate and 30 years of timeframe..
Table 7. Benefit cost ratio of intervention programs
Birdwatching Reforestation
Goat
Agriculture
7.16
27.96 11.47
0.02
The contribution of the agriculture enhancement to the NPV is the smallest. The
Agricultural value increases only 14% despite doubling the production because the
program reduces the agricultural land to 4000 ha.
Beneficiario COLFUTURO 2010
If the benefit-cost ratio is considered (Table 7), the Agricultural program becomes
unfeasible within the assumptions and benefits described on chapter 4, mainly because the
high costs incurred. Still, there might be other side-effects not considered in this model as
agricultural profits were the only ones considered. The table 7 shows the benefit-cost ratio
of the other projects. For practical terms, the benefits of the Medicinal, Pharmaceutical
and agricultural values were summed to summarize the benefits of the restoration
program.
4.4. THE SENSITIVITY ANALYSIS
The sensitivity analysis plays an important role when simulation models are evaluated.
Sensitivity analysis is used to determine how “sensitive” a model is to changes in the value
of the parameters of the model and to changes in the structure of the model.
Sensitivity tests help the modeler to understand the dynamics of a system. Experimenting
with a wide range of values can offer insights into the behavior of a system in extreme
situations, discovering values where the model greatly changes and discovering the
parameters which its behavior greatly changes general behavior of the system, therefore,
allowing the reviewer to improve model’s conclusions and confidence (Breierova &
Choudhari, 2001). For example, the use of different discount rates will bring different NPV
and could change the order of preference of the evaluated scenarios showing. The
sensitivity analysis helps to introduce robustness to our conclusions showing the changes
of NPV when other discount rates are chosen.
For example, the sensitivity analysis allows the reviewer to determine what level of
accuracy is necessary for a parameter and which are reasonable to avoid or keep. For
instance, if the tests reveal that the model is insensitive, then, it could be possible to use
estimation rather than a value obtained by accurate measurements which is more
expensive and time consuming to obtain. If the model behaves as expected from real world
observations, it gives some indication that the parameter values reflect, at least in part, the
“real world”. As previously noted, sensitivity analysis can also indicate which parameter
values are reasonable to use in the model and help to select which are useful and
valid(Breierova & Choudhari, 2001).
Beneficiario COLFUTURO 2010
Many parameters in the model represent quantities that are hardly known because the
lack of understanding of the ecological-economic system and the availability of
information. These include for example the regeneration of the mature forest, the values
of recreation and the future tourists’ inflow, among others. Here the sensitivity analysis
plays a crucial role testing the reliability of the transferred estimations.
In this paper, I make a sensitivity analysis varying the discount rate from 1% to 15%. I also
evaluate how the NPV changes at different levels of threats. I varied the values of tourists
and grazing pressure from -100% to +100%. Independently, I changed the regeneration
rate from 1% to 10% in order to evaluate the effects on the NPV.
The sensitivity analysis showed that regardless of the discount rate, the alternative
scenario is always preferred. The Figure 20 shows the sensitivity of the NPV to the discount
rate. The figure shows that the alternative scenario is not preferred any more when a
discount rate larger than 11% is chosen. That confirms the previous conclusions that the
alternative scenario remains superior and, within the time frame and the range of discount
rates considered, the results are robust.
Figure 20. Sensitivity of the NPV to the discount rate for 30 years of simulation.
The sensitivity analyses also demonstrate that at any level of threat the alternative
scenario is in many cases preferred over the baseline (Figure 21 and 22). This
demonstrates, within the established assumptions, that the investment on the
management programs will bring higher net benefits than not doing anything.
Beneficiario COLFUTURO 2010
As expected, increasing tourism drives an increase of NPV mainly because most of the
valuations are based on the numbers of tourists (Figure 21), however, there will not be
substantial extra benefits even when the tourist amount is double. Moreover if tourism
increases the NPV will be close to zero, meaning that both scenarios provide similar
benefits and there would be none incentive for investment on the programs. High benefits
of the four programs will be evident only when tourism is reduced
Figure 21. Sensitivity of the NPV when tourism is changed using a discount rate of 5% and a
timeframe of 30 years.
The figure 22 shows how the NPV changes when the grazing pressure is increased or
decreased. The analysis shows that if Bonaire government wants to have more economic
benefits without investing in management programs, it is necessary to reduce the amount
of goats more than the half of the current number.
Figure 22. Sensitivity of the NPV when grazing is changed using a discount rate of 5% and a timeframe of 30
years.
Beneficiario COLFUTURO 2010
The sensitivity analysis of the TEV to the changes on the regeneration rate of the forest for
the baseline and alternative scenarios are shown in Figures 23 and 24. There are no
changes in the TEV in the baseline scenario when the regeneration rate is varied from 1%
to 10% because for all the runs the grazers end up degrading the forest as shown in Figure
15. In the other hand, increasing the regeneration rate from 1% to 10% in the alternative
scenario would bring economic benefits up to $11 million. The largest marginal benefit
obtained from changes in 1% of the regeneration rate are found when the rate rises from
1% to 2%. A change of 1% of the regeneration rate made at values farther than 6% brings
only gains of about $1 million.
Figure 23. Sensitivity of the annual TEV to the changes on the natural regeneration parameter
from 1% to 10 for the baseline scenario.
Figure 24. Sensitivity of the annual TEV to the changes on the natural regeneration parameter
from 1% to 10% for the alternative scenario. In brackets the NPV ($Million) is represented
using a discount rate of 5%.
Beneficiario COLFUTURO 2010
BOX 1.
THE VALUE OF POLLINATION AND SEED DISPERSAL
As review on section 3.2.2. the importance of pollination and seed
dispersal is immense for the tropical dry forest. A stand-alone submodel based on the ecological module was done in order to estimate
the value of these services (see Appendix for details). Due to the
importance of the results and the limitation of information to link
this model to the general NPV I present them in this special section.
A what if scenario was formulated in order to compare the influence
of the pollination and seed dispersal service on the extension of
mature forest. I imagined a Bonaire island with seed dispersers and
pollinators and another lacking them.
Assuming that one hectare of dry forest regenerated solely by the
activity of animals costs the same as the reforestation of one hectare
of a forest with the same characteristics, I found that the value of
pollination and seed dispersal is on the order of $17 million.
Apart that the restoration program may be more efficient, the only
difference that distinguishes pollination and dispersal service with
the reforestation program is that nature does it for free. A
reforestation program emulates pretty much what pollinators and
seed disperser do in nature: choose the best seed, germinate them,
produce seedlings and planting them, giving the best conditions to
become young trees. That is why it is chosen as a proxy value.
Beneficiario COLFUTURO 2010
5. DISCUSION
This paper aims to valuate the economic benefits of the tropical dry forest on Bonaire by
using a dynamic simulation model. It shows that in that the maximum benefits of the
mature forest are never reached the revenues from environmental conservation practices
might be as high as $45million bringing $8.9 million of compared with the scenario of
environmental inaction. I also have shown that modeling ecological functions and its socioeconomical interactions is a useful tool to bring to the policy agenda ecological values that
are given for granted such the pharmaceutical value, and pollination and seed dispersal.
The results suggest that the implementation of individual programs will have different
effects on the NPV. For instance, the goat program showed to contribute to most of the
values but the agricultural program incurs in more costs than benefits provided. The
birdwatching program has the great potential to contribute up to 25% of the NPV while the
benefits of the restoration program are evident when it is applied with other programs.
The benefits could be rise if for example the agriculture project is changed to incur fewer
costs and more benefits are taken into account.
The sensitivity analyses showed that at certain level of threats exist efficient allocations
where the economic benefits of the baseline scenario are equal or larger than the benefits
of the alternative scenario. According with the results an emphasis must be placed on
maintaining current levels of tourism and reducing the grazers.
While there are enough facilities on Bonaire to support the increase of tourism the
reduction or increase of tourism is not a feasible option. For the baseline scenario, the
increase of tourism will not bring additional benefits while the reduction of tourism on the
baseline scenario will only reduce the TEV and, for the alternative scenario, it will level the
benefits with the baseline scenario.
A possible option is to maintain current levels of tourism and invest in a program that
reduces the grazers in a half and implements goat husbandry among the farmers. This
measurement is an efficient option since the goat program brings additional benefits when
is implemented with other programs. Although, it may reduce possible social conflict with
Beneficiario COLFUTURO 2010
eradication measurements preserving the culture associated with goats and improving the
farmers’ income.
An important result of this research was the value of pollination and seed dispersal.
Despite that was not possible to include this sub-model in the total economic valuation due
to the limitation of information to link it, the reveals how important animals are for the
regeneration of the forest. The results suggest that it is possible to accelerate the
regeneration of the mature forest and reduce reforestation costs by enhancing animal
pollination and seed dispersal, for example, by habitat improvement and the construction
of perches and forest corridors along the open landscape.
Part of the relevance of this project is just not only the development of the model but the
economic valuation of the tropical dry forest on Bonaire. The project did not limit itself to
find the linkage between the change of forest extension and the consequent change in
biodiversity. The model reflects these changes in an economical manner giving a monetary
value to the change of these services and making more understandable to decision makers.
The project proposes four intervention programs relevant for Bonaire context : goat
control-husbandry, agriculture enhancement, birdwatching and a reforestation program.
The document facilitates the evaluation of the effectiveness of such programs using the
NPV and the benefit-cost ratio.
Besides the important results the raw assumptions undermine the credibility of the
outcome. Sensitivity analyses were performed in order to test the robustness of the results
showing that in most of the cases the intervention is preferred against the current
practices. A range on the NPV is preferred than a single value but the availability of
information to design a maximum and a minimum was impossible to get.
The results have to be taken with caution since they represent an abstraction of the reality
and still information more reliable is needed, assumptions may be over simplistic in many
cases. It is important to consider for the future that impacts of the threats on the NPV may
be underestimated since the rate of increase of tourism shows to be insensible to the
“Forest state indicator”. Future improvements of the model should be a part of future
research and the inclusion of explicitly spatial valuation of ecosystem services must be
Beneficiario COLFUTURO 2010
priority, hence, make it possible to integrate with different land management plans
throughout the forthcoming years.
As previously mentioned, the research on the ecology of the dry forest is at an early stage
and economic information is limited, many coming from gray literature and expert’s
knowledge. However the main attributes of the ecologic-economic system were reflected
on the model. Further research topics may include the effect of disturbance on the
occurrence and diversity of animals, the response of tourists to environmental quality and
ecological information on Bonaire’s forest such as the abundance of birds in forests with
different environmental qualities.
This paper evaluated the economic consequences of tropical dry forest change on Bonaire
Island using a dynamic simulation model. The project shows that the use of such kind of
models may be useful for comparing scenarios and finding efficient allocation of the
projects. By comparing the effectiveness of four intervention programs, it was possible to
argue that an efficient option for intervention might focus on the reduction of goats in 50%
and maintain the tourism under the current levels. The research contributes to understand
the complex ecological-economic interface of Bonaire Island and represents a tool for
allocation of resources and better decision-making by local stakeholders in order to achieve
a sustainable future.
Beneficiario COLFUTURO 2010
6. REFERENCES
Aide, T. Mitchell, Jess K Zimmerman, John B Pascarella, Luis Rivera, y Humfredo Marcano-Vega. 2000. «Forest
Regeneration in a Chronosequence of Tropical Abandoned Pastures: Implications for Restoration Ecology».
Restoration Ecology 8 (4): 328–338.
Allsopp, M. H, W. J De Lange, y R. Veldtman. 2008. «Valuing insect pollination services with cost of replacement».
PLoS One 3 (9): e3128.
Anderson, Jill, Joe Saldaña Rojas, y Alexander Flecker. 2009. «High-quality seed dispersal by fruit-eating fishes in
Amazonian floodplain habitats». Oecologia 161 (2): 279–290. doi:10.1007/s00442-009-1371-4.
Blackburn, Tim M, Phillip Cassey, Richard P Duncan, Karl L Evans, y Kevin J Gaston.2004. «Avian Extinction and
Mammalian Introductions on Oceanic Islands».Science 305 (5692) (: 1955–1958
Borst L, de Haas SA (2005) Hydrological research Bonaire: a hydrogeologicalinvestigation of Bonaire’s water
system. Acacia Institute p7,11
Breierova L. and Choudhari M. An introduction to sensitivity analysis. Massachusetts Institute of Technology, D4526-2
Brock, A. Ferrer M and Scholte S. 2011. Economic Valuation of Medicinal Plants for Local and Global Use:The Case
of Bonaire. Course Report for the Faculty of earth and life sciences.Vrije Universiteit Amsterdam
Burke, l. Maidens j. 2004. Corals at risk in the caribbean. World Resource Institute, Washington.
Carson, I. I., y S. John. 2004. «Introduction to modeling and simulation». En Proceedings of the 36th conference on
Winter simulation, 9–16. http://dl.acm.org/citation.cfm?id=1161740.
Chettri, N, E Sharma, y D.C Deb. 2001. «Bird community structure along a trekking corridor of Sikkim Himalaya: a
conservation perspective». Biological Conservation 102 (1) : 1–16.
Chiabai, Aline, Chiara Travisi, Anil Markandya, Helen Ding, y Paulo Nunes. 2011. «Economic Assessment of Forest
Ecosystem Services Losses: Cost of Policy Inaction». Environmental and Resource Economics 50 (3): 405–445.
doi:10.1007/s10640-011-9478-6.
Cigna, A. A. 1993. «Environmental management of tourist caves». Environmental Geology 21 (3): 173–180.
Cockle, Kristina L., Kathy Martin, y Mark C. Drever. 2010. «Supply of treeholes limits nest density of cavitynesting
birds in primary and logged subtropical Atlantic forest». Biological Conservation 143 (11): 2851–2857.
Connell, John. 2009. «Birdwatching, Twitching and Tourism: towards an Australian perspective». Australian
Geographer 40 (2): 203–217.
Cruz, F., V. Carrion, K. J Campbell, C. Lavoie, y C. DONLAN. 2009. «Bio-Economics of Large-Scale Eradication of Feral
Goats From Santiago Island, Galápagos». The Journal of Wildlife Management 73 (2): 191–200.
De Freitas, J. A., Nijhof, B. , Rojer, A.and Debrot, A. (2005) Landscape ecological vegetation map of the island of
Bonaire(Southern Caribbean). Amsterdam: Royal Netherlands Academy of Arts and Sciences.
Debrot, Adolphe O., and John A. de Freitas. 1993. “A Comparison of Ungrazed and Livestock Grazed Rock
Vegetations in Curacao.” Biotropica 25 (3): 270–280.doi:10.2307/2388785.
Debrot, A., E.H. Meesters and D. Slijkerman, 2010. Assessment of Ramsar site Lac Bonaire. IMARES. Wageningen
UR report number C066/10, 31 pp
DEZA (2008). Department of Economic and Labour Affairs Island Territory of Bonaire. The Bonaire economic note.
Fernández-Juricic, Esteban.2000. «Local and regional effects of pedestrians on forest birds in a fragmented
landscape».The Condor 102 (2): 247–255.
FSW.2012.
United
Stated
Fish
and
wildlife
service.
Consulted
June
4th
2012.
http://www.fws.gov/southeast/es/partners/StateFactSheets/Caribbean_longv.pdf
Garcia M. La alimentación del Caprino 2005. In Manual de producción de Caprinos y Ovinos. Edited by Dickinson L.
and Muñoz G. INIA – Instituto Nacional de Investigaciones Agrícolas - Centro de investigaciones Agricolas del
estado de Lara. Barquisimeto, Venezuela.
GBGM. General Board of Global Ministries. Site: http://new.gbgm-mc.org/advance/projects/conferencepartnerchurch/details/index.cfm?action=details&id=3018772&code=418705&more=1
Hein, L.,and others. 2009. «The Economic Value of the Pollination Service, a Review Across Scales». Open Ecology
Journal 2: 74–82.
Hougner C, Colding J., and Söderqvist T. 2006. «Economic valuation of a seed dispersal service in the Stockholm
National Urban Park, Sweden».Ecological Economics 59 (3) (364–374.
Jacobson, Susan Kay. 2009. Communication Skills for Conservation Professionals. 2. ed. Island Press.
Kandelaars, P. 1997. «A dynamic simulation model of tourism and environment in the yucatan peninsula». Working
Papers. http://ideas.repec.org/p/wop/iasawp/ir97018.html.
Beneficiario COLFUTURO 2010
Kangas, K., M. Luoto, A. Ihantola, E. Tomppo, y P. Siikamäki. 2010. «Recreation-induced changes in boreal bird
communities in protected areas».Ecological Applications 20 (6): 1775–1786.
Kim, Aise Kyoungjin, Justine Keuning, Jeremy Robertson, Y Sonia Kleindorfer. 2010. «Understanding the
Birdwatching Tourism Market in Queensland, Australia». Anatolia 21 (2): 227–247.
Lacle, F. 2011.Recreational and cultural value of Bonaire’s nature to its inhabitants.Research project Msc.
Environment and resource management 2010-2011.Vrije University of Amsterdam.The Netherlands.
Lasky, J.R., y T.H. Keitt. 2010. «Abundance of Panamanian dry-forest birds along gradients of forest cover at
multiple scales». Journal of Tropical Ecology 26 (1): 67.
Le Houerou H. N.and C. H. Hoste. 1977. Rangeland Production and Annual Rainfall Relations in the Mediterranean
Basin and in the African Sahelo-Sudanian Zone. Journal of Range Management Vol. 30, No. 3 (May, 1977), pp.
181-189
Lee, Choong-Ki, Jin-Hyung Lee, Tae-Kyun Kim, y James W. Mjelde. 2010. «Preferences and willingness to pay for
bird-watching tour and interpretive services using a choice experiment». Journal of Sustainable Tourism 18
(5): 695–708.
MEA Millennium Ecosystem Assessment (2005) Ecosystems and human well-being: biodiversity synthesis.World
Resources Institute, Washington
Machado IC and . Lopes A.V.2004. Floral traits and pollination systems in the Caatinga, a Brazilian tropical dry
forest. Ann. Bot., 94 (2004), pp. 365–376
MIM. 2012. Afvalplan Bonaire 2012 – 2017. Ministerie van Infrastructuur en Milieu.
Nobre, A. M., J. K. Musango, M. P. De Wit, y J. G. Ferreira. 2009. «A dynamic ecological–economic modeling
approach for aquaculture management». Ecological Economics 68 (12): 3007–3017.
Nouel G y Rincón J. 2005. Utilización de recursos del bosque seco tropical para la alimentación de caprinos y
ovinos. In Manual de producción de Caprinos y Ovinos. Edited by Dickinson L. and Muñoz G. INIA – Instituto
Nacional de Investigaciones Agrícolas - Centro de investigaciones Agricolas del estado de Lara. Barquisimeto,
Venezuela.
NRC. 2005. Ecosystems, Committee on Assessing and Valuing the the Services of Aquatic and Related Terrestrial,
and National Research Council. 2005. Valuing Ecosystem Services: Toward Better Environmental DecisionMaking. National Academies Press.
OLB. 2012.Openbaar Lichaam Bonaire. www.bonairegov.an visited june 20 2012
Panagos P., Jones A., Bosco C., Senthil Kumar P.S. 2011. Land capability and land use map of Bonaire in European
digital archive on soil maps (EuDASM): Preserving important soil data for public free access (2011)
International Journal of Digital Earth, 4 (5), pp. 434-443.
Pearce, D. W. 2001. «The economic value of forest ecosystems». Ecosystem health 7 (4): 284–296.
Quesada, M., G.A. Sanchez-Azofeifa, M. Alvarez-Añorve, K.E. Stoner, L. Avila-Cabadilla, J. Calvo-Alvarado, A.
Castillo, et al. 2009. «Succession and management of tropical dry forests in the Americas: Review and new
perspectives». Forest Ecology and Management 258 (6): 1014–1024.
Ricketts, T. H. 2004. «Tropical forest fragments enhance pollinator activity in nearby coffee crops». Conservation
Biology 18 (5): 1262–1271.
ROB. 2010. Ruimtelijk Ontwikkelingsplan Bonaire.
Rochelle S, Pickering,C and Castley G. 2011. «A review of the impacts of nature based recreation on birds». Journal
of Environmental Management 92 (10) 2287–2294.
Simpson, R. D., R. A. Sedjo, y J. W. Reid. 1996. «Valuing biodiversity for use in pharmaceutical research». Journal of
Political Economy: 163–185.
STINAPA. 2012. http://www.washingtonparkbonaire.org/ consulted 12 June, 2012.
TEEB.2010.The Economics of Ecosystems and Biodiversity: The Economics of Ecosystems and Biodiversity:
Ecological and Economic Foundations. Edited by Kumar, Pushpam. Routledge publishers.
Tisdell, Clement A, y Clevo Wilson. 2003. Visitor Profiles and Environmental Attributes, especially of Birds,
Attracting Visitors to Lamington National Park: Tourist Attitudes and Economic Issues. Economics, Ecology
and Environment Working Paper. University of Queensland, School of Economics.
Traveset , Anna and David M. Richardson. 2006. «Biological invasions as disruptors of plant reproductive
mutualisms».Trends in Ecology & Evolution 21 (4)
Trzcinski, M.K., L. Fahrig, y G. Merriam. 1999. «Independent effects of forest cover and fragmentation on the
distribution of forest breeding birds». Ecological Applications 9 (2): 586–593.
UNNews, 2012. http://www.un.org/apps/news/story.asp?NewsID=41970&Cr=tourism&Cr1= Visited June 23 2012.
Uyarra, M. C, I. M Cote, J. A Gill, R. R.T Tinch, D. Viner, A. R Watkinson, y others. 2005. «Island-specific preferences
of tourists for environmental features: implications of climate change for tourism-dependent states».
Environmental conservation 32 (1): 11–19.
Beneficiario COLFUTURO 2010
Van Beukering, P. J. H., y H. S. J. Cesar. 2004. «Ecological economic modeling of coral reefs: evaluating tourist
overuse at Hanauma Bay and algae blooms at the Kihei coast, Hawai’i». Pacific Science 58 (2): 243–260.
Van Bezouwen L., van den Tooren M., Radema M.,Mijnhart I., Puts .2009. Herstructurerings advies voor de
Dienst LVV op Bonaire Een analyse van de sectoren Landbouw, Veeteelt en Visserij-. Academic
Consultancy Training Wageningen University.
Velando, Alberto, y Ignacio Munilla. 2011. «Disturbance to a foraging seabird by sea-based tourism: Implications
for reserve management in marine protected areas». Biological Conservation 144 (3)
Wells and Debrot 2008. Bonaire in Important Bird Areas in the Caribbean, 2008. Birdlife International.
Wong. 1998. «Coastal tourism development in Southeast Asia: relevance and lessons for coastal zone
management». Ocean & Coastal Management 38 (2)
Beneficiario COLFUTURO 2010
APPENDIX: THE VALUE OF POLLINATION AND SEED DISPERSAL
As reviewed previously on section 3.2.2., pollination and seed dispersal play an important
role to maintain the biodiversity and the natural regeneration of the forests. Both
vertebrates and invertebrates such as bees, bats and hummingbirds contribute to the plant
establishment and reproduction of plants consuming the nectar of the flower and indirectly
carrying the pollen grains from one individual to another fertilizing the plants and making
the fruits possible. Some other animals make possible the establishment of new seedling
eating the fruits and indirectly consuming the seed and carrying them to new areas in the
forests.
The value of pollination services is immense, not only to maintain natural populations,
habitat and biodiversity but for the agricultural sector. For example, coffee yields and
coffee quality increase near patches of forest that provided habitat to wild bees (Ricketts et
al 2004). The value of natural pollination is most likely estimated in fruit crops where the
dependence of cultivars is high. Valuation of pollination on drylands such as Western Cape
ascend up to US$358 but should rise to billions in other parts of the world (Allsopp et al
2008).
Pollination services are getting more attention especially insect pollination as invertebrate
and vertebrate pollinators have declined through time and with them the yields of
agricultural crops (Hein et al 2009). On the other hand, seed dispersal has received less
attention as an ecosystem service and has been less commonly valuated. Estimates of the
contribution of a pair of jays to the Boreal forest regeneration ranges from US$2,100 to
US$9,400 (Hougner et al 2006). Part of the difficulty on the valuation of such services is the
different ways to measure the pollinators’ contribution, the natural variability of the
ecosystem and the markets and the species specific effects that leaves no room for
generalizations. In fact, the current valuations of pollination are quite controversial
(Allsopp et al 2008). Usually production function and replacement cost methods are
commonly used, the first is a sort of a dose-response method where the amount of
pollinators is correlated with the quality and quantity of fruits. In the replacement costs the
value of a man-made solution such as hand pollination cost is used as a proxy of the value
of the pollination.
Beneficiario COLFUTURO 2010
The aforementioned valuation methods are very limited, controversial and time consuming
(Allsopp et al 2008). A dynamic simulation model work for these general valuations where
constraints in time are shown, budget and scale urge. Far from being a picture of the real
world, simulation models include the main interactions and show explicitly the economic
benefits and show the tradeoff between different ecosystem services.
I used the baseline scenario, setting the grazing pressure as zero otherwise the effect will
not be seen because the degradation. I ran the model during the 30 years and obtained the
net present value of pollination and seed dispersal using a discount rate of 5%.I set the
“Facilitated regeneration” parameter as 1% for the scenario with available pollinators and
seed disperser and 0% for the scenario without the interaction. I evaluated the effect
through the annual hectares of Mature Forest.
The results can be seen in the figure 26. With an average of 91 ha/year of mature forest
(Standard deviation= 27 ha), the net present value of pollination and seed dispersal is
US$17.4 million.
Figure 26. Effects of the pollination and seed dispersal on the mature
forest extension.
Beneficiario COLFUTURO 2010