The Explorers Cub - Narrative Report
American crocodile (Crocodylus acutus) in the waters of the Wildlife Refuge Monte Cabaniguán-Ojo de
Agua, Cuba (Photo by Natalia A. Rossi)
June 27th to July 16th, 2013
Natalia A. Rossi
PhD student & Faculty Fellow
Department of Ecology, Evolution and Environmental Biology
Columbia University
Trip overview
From June 29 to July 16 of 2013 I traveled to the Wildlife Refuge Monte CabaniguánOjo de Agua in the Gulf of Guacanayabo, Eastern Cuba, to conduct a fieldwork to research and
monitor the nesting activity of American crocodiles (Crocodylus acutus). With the overall goal
of better understanding the reproductive ecology of American crocodiles in the area and its
relationship with climate and environmental variables, with the participation of Dr. George
Amato from the American Museum of Natural History and the collaboration of a Cuban
research team, we: i) located, characterized and registered total number of crocodile nests and
number of successful nests among four nesting sites; ii) marked, measured and weighted
recently emerged hatchlings, sexing a subsample of 30 nests; iii) collected skin tissue samples
of hatchlings and juveniles for further genetic analyses . In addition, I visited the Instituto de
Meteorologia de Cuba in Havana and gathered a data set for climate and environmental data
including maximum and minimum temperatures during the nesting season, total rainfall
during the nesting season, and time (in days) since tropical storm/hurricane occurred (for
periods 1993 to 2012). Next steps include working at the Sackler Institute of Comparative
Genomics at the American Museum of Natural History to conduct genetic analyses of
parentage and assess the occurrence of multiple paternity in Crocodylus acutus, and explore
the use of generalized linear models GLM,(McCullagh and Nelder 1989) for the analyses of the
dependence of reproductive success on the climate and environmental variables.
2 Trip itinerary
Date
Thursday, June 27,2013
Friday, June 28, 2013
Saturday, June 29, 2013
Sunday, June 30, 2013
Monday, July 1, to Sunday
July 7,2013
Monday, July 8, 2013
Tuesday, July 9,2013
Wednesday, July 10,2013
Thursday, July 11, 2013
Activity
•Arrival at Havana
•10AM Dr. George Amato Seminar at
University of Havana
•Meeting at University of Havana to
review fieldwork logistics
• Departure to Wildlife Refuge Monte
Cabaniguán-Ojo de Agua
• Arrival to the Wildlife Refuge Monte
Cabaniguán-Ojo de Agua
•Fieldwork at the Wildlife Refuge Monte
Cabaniguán-Ojo de Agua
• Travel from the Wildlife Refuge Monte
Cabaniguán-Ojo de Agua to the Zapata
National Park
•Return to Havana
• Meeting at the National Enterprise for
the Conservation of Flora and Fauna
(ENPFF) to discuss project outcomes
• Participation in the International
Congress of Environment
Friday, July 12, 2013
• Work at UH, visit Instituto de
Meteorologia
Saturday, July 13 and
Sunday, July 14, 2013
• Work in preliminary data analyses
Monday, July 15, 2013
• Work at UH
Tuesday, July 16, 2013
• Early departure to NYC
Notes
With Dr. George Amato
Meeting with Professor Georgina Espinosa,
Professor. Vicente Berovides and Professor Yoamel
Milian Garcia
Night at Sancti Spititu
Travelled with biologist Maikel Cañizares Morera
from the Institute of Ecology and Systematics,
George Amato from AMNH, and Yoamel Garcia
Milian from University of Havana
Settling in and planning field activities with
Manuel Alonso Tabet and team
Fieldwork included beach-based nesting
monitoring, water-based monitoring, night
crocodile monitoring, and data processing and
preliminary analyses at the field station
Visited the Zapata crocodile farm and held
meetings with Park authorities including crocodile
expert Dr. Toby Ramos
Meetings with Loreta Garcia and Gabriel Brull
from ENPFF
Discussions with Protected Areas authorities and
crocodile researchers
Drafting of Crocodile of Cuba Workshop to be
carried out in November of 2013
Meetings with Professor Vicente Berovides and
Professor Georgina Espinosa Lopez
Background
The field expedition to the Wildlife Refuge Monte Cabaniguán-Ojo de Agua (WRMC) took
place from June 27 to July 16 of 2013. Dr. George Amato from the American Museum of Natural
History, biologist Maikel Cañizares Morera from the Institute of Ecology and Systematics, Yoameil
Milian Garcia from the University of Havana, and Dr. Manuel Alonso Tabet and his research team
from the National Enterprise for the Conservation of Flora and Fauna joined the field expedition.
With an extension of 626 Km², the Wildlife Refuge Monte Cabaniguán- Ojo de Agua
(20º40’53”N - 77º17’46”W) is within the most important coastal wetland ecosystems of Eastern Cuba:
3 the Delta del Cauto wetland (Alonso Tabet and Rodriguez Soberón 1998 ) (Figure 1, Figure 2). The
WRMC is located along the littoral zone of the Gulf of Guacanayabo, provinces Las Tunas and
Granma, in the lower part of river basins that join to form a continuous and complex delta system of
estuaries, lakes and mangrove swamps (Rodriguez-Soberon 2009). This area sustains the largest
population of the American crocodile (Crocodilus acutus) in its entire range of distribution (Varona 1987;
Rodríguez Soberon 2000). The WRMC is also an important stronghold for Cuban iguanas (Cyclura
nubila), as well as numerous colonial nesting waterbirds (Varona 1987).
Crocodilus acutus nesting in this wetland is concentrated on a few beaches scattered along the
gulf shoreline, and in a two hectares patch of raised land within the mangrove swamp, situated 2 km
inland (Rodríguez Soberon 2000; Alonso Tabet 2009). Five of these nesting areas are permanent,
covering a combined surface area of 9.2 hectares. More than 250 crocodile nests hatch each year in
nesting areas within this wildlife refuge (Alonso Tabet 2009). Given the low availability of nesting
areas and high density of crocodiles, nesting is performed in a gregarious manner and in high densities
(Alonso Tabet and Rodriguez Soberón 1998). In the WRMC, elevation, levels of exposure to the action
of tides, edaphic and other environmental features vary among nesting sites, which in turn influence
nesting success in each site (Alonso Tabet, Rodríguez Soberón et al. 2000).
Nesting of the American crocodile. American crocodile (Crocodylus acutus) permanent nesting areas
in the Wildlife Refuge Monte Cabaniguán, Cuba; Image modified from Alonso Tabet 2009
4 Crocodylus acutus plays an important ecologic role as top predator and “landscape engineer” of
wetland ecosystems (Thorbjarnarson 1989). For instance, at the WRMC, the activity of crocodiles
promotes the opening of water channels connecting water bodies previously isolated. Most of this
activity is related to C. acutus reproductive behavior, as females move throughout the landscape
searching for available sites to build nests, often times patrolling those areas until hatchlings emerge,
and build refuges for post-natal care.
Wildlife Refuge Monte Cabaniguán- Ojo de Agua. Research station Don Miguel Álvarez del Toro
(left) at the core of the Wildlife Refuge Monte Cabaniguán, where numerous waterbird species such as
flamingoes (Phoenicopterus ruber) thrive (right) (Photos by Maikel Cañizares Morera)
Crocodylus acutus is categorized locally and globally as “vulnerable” (IUCN 2010, Alonso et al.
2012), and listed in CITES Appendix I, with the exception of Cuba, included in CITES Appendix II
(Thorbjarnarson, Mazzotti et al. 2006).Although the WRMC holds the largest population of C. acutus
within its range of distribution (Varona 1987; Rodríguez Soberon 2009), the species still faces several
threats. Among them are habitat loss and fragmentation, illegal hunting, damp construction, droughts,
severe weather events such as tropical cyclones and hurricanes, and adverse effects of national and
international tourism (Alonso et al. 2012).The fact that C. acutus’ breeding populations are
concentrated in few nesting sites within Cuba during the three to four- month period where eggs are
laid and incubation occurs, makes reproductive females and hatchlings particularly vulnerable to
poaching (Alonso et al. 2012).
5 This field expedition was carried out with the main goal of better understating C. acutus’s
reproductive ecology in one of the key and most abundant breeding grounds for the species in Cuba
and its entire range. Data and samples gathered in this trip will build up to the data gathered for my
PhD dissertation at the Department of Ecology, Evolution and Environmental Biology at Columbia
University. Specifically, data obtained in this trip will be used to i) characterize the mating system of
the Cuban C. acutus; and ii) assess the influence of climate and environmental variables on the nesting
success of C. acutus at the Wildlife Refuge Monte Cabaniguán-Ojo de Agua, Cuba.
Research results & final steps
Crocodile nesting monitoring: efforts to locate and identified nests started in early March and
continued for the duration of the field expedition. A total of 146 nests were located and marked. Of
these, 71 where located at Jobabito nesting site, 46 at Salinas nesting site, 11 at Soloburen-Ojo de
Agua nesting site, and 18 at Jijira nesting site. All nests were monitored from early May until the end
of June to record nesting success, and mark, sex, weight and sample hatchlings when possible. Nests
with at least one surviving hatchling (or traces of recently emerged hatchlings taken by the mothers)
were considered successful.
Crocodile nesting monitoring at the WRMC. Hatchling emerging from nest (left), and measuring of
hatchlings upon emergence (right) (Photos by Natalia Rossi and Yairén Alonso Jiménez)
6 During the field expedition, approximately 150 hatchlings were marked, weighted and
measured. A skin tissue sample from the tale of each hatchling was collected and saved in ethanol 95%
until DNA extraction. Samples are stored at University of Havana until further analyses to be done at
the Sackler Institute of Comparative Genomics at the American Museum of Natural History.
Dr. George Amato (AMNH) joining field expedition 2013 (Photos by Maikel Cañizares Morera)
Habitat characterization: each nesting site (Jobabito, Salinas, Soloburen-Ojo de Agua, and Jijira)
were characterized in terms of total area, elevation above the sea level, substrate type, and levels of
exposure (Table 2). In addition, soil samples were taken for further soil composition/texture analyses.
Climate and environmental variables: on Friday, July 12, I visited the Instituto de Meteorologia
in Havana, gathering datasets on climate variables including maximum and minimum temperatures
during the nesting season, total rainfall during the nesting season, and time (in days) since tropical
storm/hurricane occurred (for periods 1993 to 2012).
Overall, this field expedition helped advance the research on the reproductive ecology of
Crocodylus acutus in the WRMC, and gather data and samples for my PhD dissertation at the
Department of Ecology, Evolution and Environmental Biology at Columbia University. Future steps
include working at the Sackler Institute of Comparative Genomics at the American Museum of
Natural History to conduct genetic analyses of parentage and assess the occurrence of multiple
paternity in Crocodylus acutus, and explore the use of generalized linear models GLM (McCullagh and
7 Nelder 1989) for the analyses of the dependence of reproductive success on the climate and
environmental variables. Finally, I will present results of this project at the IX International Wetland
Symposium in Zapata, Cuba, in November 12-15 of 2013. In addition I will present my results at the
Wildlife Conservation Society and at the Institute of Latin American Studies at Columbia University
on dates to be determined.
Recently emerged hatchings at the WRMC (Photos by Natalia Rossi and Maikel Cañizares Morera)
Crocodile nesting monitoring at the WRMC. Nests were surveyed in search for hatchlings or traces
of recently emerged hatchlings by digging into the ground in previously identified and marked nesting
sites (Photos by Yairen Tabet and Natalia Rossi)
8 Interior lagoons and water channels were wildlife thrive at the WRMC. Caribbean flamingos
(Phoenicopterus ruber; left) and American crocodiles (Crocodylus acutus; right) in the waters of the
WRMC (Photos by Natalia Rossi and Manuel Alonso Tabet)
Crocodile captures I. American crocodiles (Crocodylus acutus; left) were identified from the boat, and
captured using 50 mm – mesh size nets (right) (Photos by Natalia Rossi and Maikel Cañizares Morera)
9 Crocodile captures II. After capture, American crocodiles (Crocodylus acutus; left) were weighted,
measured, checked for marks, and a skin tissue sample was taken (Photos by Maikel Cañizares Morera
and Natalia Rossi)
10 References
Alonso Tabet, M. (2009). Comportamiento del cocodrilo americano (Crocodylus acutus) en el Refugio
de Fauna Monte Cabaniguan, Cuba. Republica de Cuba, Universidad de Alicante/ Universidad
de Pinar del Rio "Hermanos Saiz Montes de Oca".
Alonso Tabet, M. and Rodriguez Soberón R. (1998). "Observations on nesting behavior of Crocodylus
acutus." Crocodile Specialist Group Newsletter 17(1): 11-13.
Alonso Tabet, M., Rodríguez Soberón R., et al., Eds. (2000). Influencia de la geomorfología del hábitat
sobre la nidificación de Crocodylus acutus en el refugio de fauna Monte Cabaniguán, Cuba. 15ª
Reunión de Trabajo del Grupo de Especialistas de Cocodrilos SSC/IUCN. Varadero, Cuba.
González Alonso, H., L. Rodríguez Schettino, et al., Eds. (2012). Libro Rojo de los Vertebrados de
Cuba. Habana, Editorial Academia.
IUCN (2010). "IUCN Red List of Threatened Species. Crocodylus acutus. Crocodile Specialist Group."
Janowitz, S. A. and K. Fischer (2011). "Opposing effects of heat stress on male versus female
reproductive success in Bicyclus anynana butterflies." Journal of Thermal Biology 36(5): 283287.
Milian-Garcia, Y., M. Venegas-Anaya, et al. (2011). "Evolutionary History of Cuban Crocodiles
Crocodylus rhombifer and Crocodylus acutus Inferred From Multilocus Markers." Journal of
Experimental Zoology Part a-Ecological Genetics and Physiology 315A(6): 358-375.
Rodriguez-Soberon, R. (2009). Situacion, estrategia de conservacion y uso sostenible de Crocodylus
acutus en
Cuba. Republica de Cuba. Republica de Cuba, Universidad de Alicante/Universidad de Pinar
del Rio "Hermanos Saiz Montes de Oca"
Rodríguez Soberon, R. (2000). Situación actual de Crocodylus acutus en Cuba. Proceedings of the 15th
Working
Meeting of the Crocodile Specialist Group, IUCN, The World Conservation Union, Gland,
Switzerland and Cambridge, UK: xvii + 541 p.
Thorbjarnarson, J., F. Mazzotti, et al. (2006). "Regional habitat conservation priorities for the
American crocodile." Biological Conservation 128(1): 25-36.
Thorbjarnarson, J. (1989). "Ecology of the American Crocodile, Crocodylus acutus." In Crocodiles,
Their Ecology, Management and Conservation. A Spetial Publication of the Crocodile
Specialist Group. IUCN Publications. N.S. Gland, Switzerland: 228-258.
Varona, L. (1987). "The Status of Crocodylus acutus in Cuba " Caribbean Journal of Sciences 23(2):
256-259.
Weaver, J. P., D. Rodriguez, et al. (2008). "Genetic Characterization of Captive Cuban Crocodiles
(Crocodylus rhombifer) and Evidence of Hybridization With the American Crocodile
(Crocodylus acutus)." Journal of Experimental Zoology Part a-Ecological Genetics and
Physiology 309A(10): 649-660.
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