Conceptual Frameworks
Game Species
Disturbance and Structure
Habitat Types
Spatial Configuration
Conceptual Frameworks
Biophysical factors: topography, climate, soils, npp, water,
nutrients, etc.
Conceptual Frameworks
The framework that we will explore today is that:
abiotic factors vary across landscapes,
influence spatial patterning of disturbance
and plant recovery and growth,
may limit the distribution and performance of
wildlife populations and communities,
and influences human land use.
History
Merriam (1894) – broad vegetation bands with latitude and altitude termed “life
zones”
Clements (1936) and Holdridge (1967) - Defined biomes based on climate.
Whittaker (1956) and Daubenmire (1956) – distribution of plant species across
environmental gradients.
Hutchinson (1959) - “what factors limit the number of species in a place”? :
habitat heterogeneity, habitat area, trophic structure, evolutionary processes,
and available energy.
History
Brown (1981) - Ecologists diverged in the 1970s, either to study ecosystems or
to seek a better understanding of interactions among species, but ignoring
abiotic controls.
Wright’s 1983 paper reopened interest in energy/diversity relationships, but
largely among biogeographers and those ecologists concerned with
developing models to predict geographic variation in species richness.
Caughley (1987) – animal distributions across climate and soils.
Currie (1991) – continental community richness based on energy.
History
Today –
Stand to landscape scale: continued focus on
disturbance and succession as drivers of vegetation
and biodiversity, but case studies of abiotic controls
Regional to global scales: climate and ecosystem
energy as major drivers of land use and biodiversity
Beginnings of integration of the two perspectives for
local to continental scale conservation
Lecture Topics
Ways abiotic factors influence individual
organisms.
Interactions with ecological processes that drive
spatial variation in landscapes: disturbance and
plant growth.
Effects on populations and communities.
Implications for management.
Abiotic Factors as Niche Axes
Climate, topography, soils may be resources
or conditions that affect the fitness of an
organism.
Niche (Hutchinson 1957) – range of abiotic
and biotic conditions and resources required
by an organism for survival, growth, and
reproduction.
Abiotic Factors as Niche Axes
Niche (Hutchenson 1957) – range of abiotic and biotic
conditions and resources required by an organism for
survival, growth, and reproduction.
Key point: To the extent that abiotic and biotic limiting
factors vary across a landscape, we expect survival,
reproduction, and abundance of a species to vary
accordingly.
Abiotic Factors and Ecological
Processes
Primary Productivity:
Abiotic Factors and Ecological
Processes
Primary Productivity:
Abiotic Factors and Ecological Processes
Figure 7.
Distribution of NPP and exurban
development across the Greater Yellowstone
Ecosystem. Notice that areas of highest NPP
are largely outside of the national parks and
overlap with exurban development. Data from
Gude et al. in press.
MODIS Gross Primary Productivity
Abiotic Factors and Ecological Processes
Percentage increase in NPP (1982–1998),
computed by multiplying the linear trend at
each location by the number of years in the
time period (17), then dividing by the 1982
NPP. Modified from Hicke et al. 2002.
Abiotic Factors and Ecological
Processes
Natural Disturbance:
• Fire
• Windthrow
• Landslides
• Avalanches
• Hurricanes
No fires
High severity
250-450 yr intervals
Light to moderate
severity
50-90 yr intervals
Ppt
lightning
Disturbance
Population
Demography
Community
Diversity
NPP
Climate, topography,
soils
Vegetation
Structure
Effects on Species Distributions
Effects on Species Distributions
Basic metabolic rate – Metabolic rate of a night-resting individual at an
ambient temperature above that at which and individual must increase
its metabolic rate to maintain heat balance.
Resting metabolic rate at the northern range limit was 2.49 times
greater than BMR for each of 14 species studied.
Effects on Species Abundances
Effects on Species Movements
Effects on Birth and Death
Temporal Variation in Climate and
Birth and Death
Spatial Variation in Abiotic
Factors and Birth and Death
Studies
?
Spatially Explicit Population Dynamics:
Sources and Sinks
Biophysical factors may cause patches to be either population
sources or population sinks.
Population densities can be similar in both sources and sinks,
because of dispersal from sources to sinks.
If a nature reserve includes only sink habitats, the population
may go extinct if source areas outside the reserve are
developed.
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Spatially Explicit Population Dynamics:
Sources and Sinks
Biophysical factors may cause patches to be either population
sources or population sinks.
Population densities can be similar in both sources and sinks,
because of dispersal from sources to sinks.
If a nature reserve includes only sink habitats, the population
may go extinct if source areas outside the reserve are
developed.
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+
+
+
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Spatially Explicit Population Dynamics:
Non-spatial
populations
Spatially explicit
populations:
Source/sink
metapopulation
Low
high
Spatial heterogeneity of habitat
Spatially Explicit Population Dynamics:
Non-spatial
populations
Spatially explicit
populations:
Source/sink
metapopulation
Low
high
Spatial heterogeneity of habitat
Key Point: To the extent that landscapes are variable
in biophysical conditions, spatially mediated
population dynamics are likely more common that is
currently realized.
Biophysical Factors and Community Diversity
Biophysical Factors and Community Diversity
Productivity, Disturbance, Diversity
Dynamic Equilibrium Hypothesis (Huston 1979, 1994)
Productivity, Disturbance, Diversity
Proulx and Mazumder 1998
All 19 comparisons from nonenriched or nutrient-poor
ecosystems exhibited
significantly lower species
richness under high grazing
than under low grazing.
Productivity, Disturbance, Diversity
14 of 25 comparisons from
enriched or nutrient-rich
ecosystems showed
significantly higher species
richness under high grazing
than under low grazing.
Proulx and Mazumder 1998
Ecosystem Energy and Species Richness: Pacific and
Inland Northwest
Coast Range
Springfield
Cle Elum
Goldfork
Yellowstone
Bird Species Richness
15
10
Coast Range
Springfield
Cle Elum
Goldfork
Yellowstone
5
Bird Species Richness
Breakpoint GPP=12266; R-squared = 0.46
Quadratic Model; R-squared = 0.44
Quadratic 95% confidence bands
Verschuyl et al.
Ecological
Applications. 2008
5000
10000
15000
Annual Gross Primary Productivity
High
Intensity of Disturbance
Huston 1994.
Low
Springfield
Low
Cle Elum
High
Landscape Productivity
McWethy, D. B., J. P. Verschuyl, and A. J. Hansen.. J. For Ecol and Mgt.
McWethy, D. B., J. P. Verschuyl, and A. J. Hansen. In Prep. Bird response to disturbance
varies with forest productivity in the Pacific Northwest. J. For Ecol and Mgt.
1. In productive settings, open canopy stands recover more rapidly and develop
more vegetative cover than in low productivity settings.
2. Consistent with the mechanisms of competitive exclusion by dominant trees,
late-seral stands have higher canopy closure and less variation in canopy closure
in productive settings.
Mean measurements of percent canopy closure were greater in later-seral stands (mature
and large-tree seral stages) in Springfield (mean = 81.09, SD = 12.86) than in Cle Elum
(mean = 74.41, SD = 15.65).
McWethy, D. B., J. P. Verschuyl, and A. J. Hansen. In Prep. Bird response to disturbance
varies with forest productivity in the Pacific Northwest. J. For Ecol and Mgt.
3. At the stand scale, bird species richness and abundance within stands is positively
related to recent disturbance in a productive landscape and is negatively related to recent
disturbance in a less productive landscape..
McWethy, D. B., J. P. Verschuyl, and A. J. Hansen. In Prep. Bird response to disturbance
varies with forest productivity in the Pacific Northwest. J. For Ecol and Mgt.
3. At the stand scale, bird species richness and abundance within stands is positively
related to recent disturbance in a productive landscape and is negatively related to
recent disturbance in a less productive landscape..
McWethy, D. B., J. P. Verschuyl, and A. J. Hansen. In Prep. Bird response to disturbance
varies with forest productivity in the Pacific Northwest. J. For Ecol and Mgt.
4. At the landscape scale, due to the first three predictions, bird species richness will increase
with increasing disturbance in the landscape surrounding survey stands..
Human Land
Use
Abiotic Factors and Ecological Processes
Figure 7.
Distribution of NPP and exurban
development across the Greater Yellowstone
Ecosystem. Notice that areas of highest NPP
are largely outside of the national parks and
overlap with exurban development. Data from
Gude et al. in press.
Human Land
Use - Africa
Balmford et.
Al. 2001
From Cincotta et al.
2000
Key Point: Biophysical factors may result in
strong overlap between the locations humans
and biodiversity.
From Cincotta et al.
2000
List one key implication of consideration of
biophysical factors for managing wildlife
populations and communities.
IMPLICATIONS FOR CONSERVATION AND MANAGEMENT
1. Landscape Classification – Map biophysical factors
across the management unit.
2.
Demography - Understand population parameters vary
across the landscape and manage accordingly.
3.
Hot Spots – Quantify community patterns over
landscape as a basis to identify, maintain, and/or
restore hot spots.
4. Multiple-use Lands- Tailor commodity extraction to the
landscape.
5. Land Allocation – Careful distribution of management
strategies and intensities within major land allocations
and among allocations may be necessary to maintain
native species.