Dr Hamish Campbell

Using Caiman Yacare as a Sentinel Species to Monitor Environmental Degradation of the Pantanal, Wetlands Brazil

The caiman are weighed, length recorded, sexed, and blood sampled at point of capture.

LocationCountryCategoriesDate
Southern PantanalBrazilBiodiversity, Central and Latin America, Community, Reptile, Wetlands8 Feb 2007

The Pantanal wetlands have recently become under increasing environmental pressure due to changes in farming practice and land use. This project aims to form a collaborative body of local community, land owners and scientists to assess and monitor the ongoing environmental degradation.

Over 3639 000 ha of land had been deforested for intensive agriculture of soya in the state which encompasses the Southern Pantanal. Each year Brazil applies over 50 000 tonnes of pesticide on soya plantations, and this is increasing by 21.7 % annually. The new wave of ‘round up’ soya pesticides are particularly harmful for insects, fish and birds, causing tumors, reproductive abnormalities and long-term genetic damage. The Pantanal acts as a drainage basin for the ‘soya plateau’ and the seasonal flood, which creates the Pantanal ecosystem, now has the potential to transport biologically hazardous anthropogenic inputs into pristine areas. Additionally, illegal gold mines are occurring in alarming abundance around Pantanal headwaters. The smelting process produces waste mercury and this toxic heavy metal has been found at high concentrations in some species of fish and piscivorous birds.

The Paraguayan Caiman (C.yacare) is found in abundance throughout the Pantanal in both pristine and heavily disturbed areas. It is an ideal sentinel species due to its low mobility, long life span, and its wide distribution in river systems and seasonally flooded wet lands. Additionally, its aquatic lifestyle and high position in the Pantanal food web make them potential biomagnifiers and bioaccumulators of organic and inorganic toxins. Using simple field techniques caiman health, growth, dispersal patterns, reproductive success and toxicological load will be assessed at chosen locations throughout the Pantanal. By comparing the caiman populations from polluted and clean sites we will be in a position to identify toxins that are transported through river systems and bioaccumulated or biomagnified through the Pantanal food web. Moreover, we can assess the resultant impact on health and reproductive success of an egg laying animal. This will be important in identifying potential threats to the approximately 500 species of bird present in the Pantanal. The 15-25 million caiman that exist in the Pantanal provide a practical solution to assessing potential toxicant load and deleterious effects to the many more endangered and fragile species (i.e. Jaguar, Manned wolf, Macaws).

For more information contact dr.hamish.campbell@gmail.com or go to http://www.uq.edu.au/eco-lab/dr-hamish-campbell

Project Update: December 2007

Caiman with radio tag.

The overall aim of this project was to develop Crocodylus caiman yacare as a sentinel species for monitoring environmental degradation of the Pantanal wetlands. However, before questions could be answered on the deleterious effects of human disturbance, it was first essential to understand how the biology of the caiman is influenced by the natural annual cycle in habitat quality. Therefore, for the last 12 months the project has focused on adding to the scarce literature on caiman ecology in the Pantanal, wetlands, Brazil.

The study over the last 12 months fell into 3 main areas, these were;

1/ Provide site specific age and sex spatial information

2/ Determine habitat and dietary requirements of various life stages

3/ Assess the effect of the annual flood and drought on caiman distribution and
population health.

So far 118 caiman have been ID-tagged, weighed and blood sampled. Results have shown that as the Pantanal dries out and the ponds disappear the caiman feed very little and draw on fat reserves laid down during the wet season when food was plentiful. Most caiman that remain within the permenant ponds throughout the dry survive on reserves until flood begins, bringing plentiful food. However, subordinate males are pushed out of permanent ponds by more dominant individuals and were found in a state of starvation. These animals may not survive through until the next rains.

We are now undertaking radio tracking studies, and using GPS dataloggers to monitor the movements of the caiman and assess how far the animals will travel to and from rivers during the wet season.

One of the main focuses of the study was to determine the level of pesticide and heavy metal in blood and tissue from caiman inhabiting various rivers throughout the Pantanal. I have a number of blood samples taken from caiman and the overall health of these animals has been assessed. However, I have been unable to get the samples analysed for levels of pesticides and heavy metals within Brazil. I would like to make an appeal to any environmental chemist working in Brazil who would like to collaborate or be involved in this study to contact me.

Project Update: May 2008

University of Birmingham students help local Pantaneros with the tagging of wild caiman.

The present abundance of C. c. yacare, has been held responsible for declining fish stocks, therefore sustainable harvesting of the species remains a hot topic. Results from our study found that in fact C. c. yacare fed predominantly during the wet season, when they inhabit the flooded grasslands and entered fed very little on fish when their numbers became crowded within ponds.

So far we have found the overwhelming importance in surface ground water in influencing the population size and structure of C.c. yacare in the Pantanal, and future study is to focus on exactly what size of C.c. yacare population a discrete area of Pantanal wetland can sustain. In depth details of the research carried out with the Rufford small grant can be found at :

Campbell, H.A., Micheli, M., & Abe, A. (2008) A seasonally dependant shift in the distribution and physiological condition of Caiman crocodilus yacare in the Paraguay River Basin. Wildlife Research 35, 150-157.

Final Report

Read about the activities undertaken and findings of this project in the final report below and a publication that has arisen from the project funded by the RSGF.

File DownloadSize
Detailed Final Report.doc35.5 KB
Wildlife Research.pdf352.27 KB
2nd RSG Grant Awarded

Hamish has been awarded a 2nd RSG grant for the development of this project
http://www.ruffordsmallgrants.org/rsg/projects/dr_hamish_campbell_0


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