Bio-diversity changes in tropical amphibian communities: global, regional or local causes?

Project leader: Mark-Oliver Rödel

Staff: Dissertation ongoing: P.J. Adeba, E. Assemian, R. Ernst, J. Glos, G.G. Kouamé, B. Tohé

Diploma thesis ongoing: A.Z. Quintana Aleman, M.A. Bangoura, N.A. Gilles, M. Kalamandeen, T. Konrad, J. Penner, M. Wegmann

Diploma thesis finished: P.J. Adeba, R. Ernst, A. Hillers, G.G. Kouamé, G. Leistner, N.Y. Rakotomanana, V.H.W. Rudolf, G. Schorr

Objectives: To understand functional processes that structure tropical faunal communities, using amphibians as model system. To investigate human impact on amphibian diversity on different scales (geographic scales; community level; genetic level). To set up applied conservation programs for tropical forests. To enhance capacity of biologists in tropical countries. To resolve taxonomic problems.

Approach: Using standardized monitoring routines we assess and analyze amphibian diversity and community composition in numerous tropical countries (most important: Ivory Coast, Benin, Guinea, Madagascar, Nicaragua, and Guyana) along habitat gradients ranging from rainforests to savannas and from pristine to highly altered (e.g. fragmented) habitats (Fig. 1). We investigate, revise and resolve current systematic problems by means of morphological, ecological, acoustic and genetic investigations. In all countries German and local students work together to enhance the scientific capacity in the respective countries. Close co-operation with national and international conservation organizations.

Progress: We accomplished and analyzed amphibian community data for about 20 pristine and anthropogenically altered sites in West Africa, Madagascar, Middle- and South America. A standardized monitoring routine was developed. Habitat preferences, distribution, taxonomy, systematics and biology of numerous amphibian species has been clarified. Leaf litter anuran assemblages from primary, secondary and fragmented West African forests have been comparatively analyzed. Students from Germany and the tropics were and/or are involved within the project.

Significance: Amphibians are very sensitive to environmental disturbances and thus well suited to be used as indicator species. Their sensitiveness has become recently dramatically visible through their worldwide decline. Our recent studies in Ivory Coast, have shown that local human impact, like logging and fragmentation, may not only result in local extinctions of several species, but also in altered community compositions and, even more seriously, may lead to substantial alteration of the processes that structure community composition and diversity patterns. Despite the fact that amphibians represent an ecologically important group of animals, are comparatively easy to investigate and are suitable bio-indicators that, due to their high diversity, may especially be useful in tropical countries, the capacity of national researchers to work with this group is almost absent in tropical Africa.

Increasing human populations, timber harvesting and mining, dramatically reduce the amount of pristine habitats in the tropics. Assessing the effects of these human activities on biodiversity and general ecosystem functions is thus of primary importance to conservation. In this context, amphibians are used as suitable surrogate species. Local staff, non-academic, as well as academic are involved at all times, guaranteeing a strong capacity building component through training in applied ecological field methods and data analysis. Generating local capacity and skills is one of the key deliverables of the project, so that the long term conservation efforts can be assured. Another major component stresses on policy development. Results of the data analyses directly contribute to conceptual planning of national protected area systems and the final designation of particular protection sites. Finally, due to close links and co-operations with the local stakeholders, the project provides guidelines for sustainable habitat use and facilitates the implementation in conservation management plans.

Future projects: Computerized models will be developed to test for general community patterns in pristine and altered habitats. Modeling (based on GIS, remote sensing) will also address the future role of climatic changes and abnormalities. Population genetics will complete community analyses.

Collaborations: Systematics and taxonomy: Zoologisches Museum und Forschungsinstitut Alexander Koenig Bonn (Prof. Dr. W. Böhme), Staatliches Museum für Naturkunde Stuttgart (Dr. A. Schlüter, Dr. A. Kwet), Museum National d'Histoire Naturelle Paris (Prof. Dr. M. Lamotte), Muséum d’histoire naturelle Genève (Dr. A. Schmitz, Dr. J.-L. Perret), Institut Royal des Sciences naturelles de Belgique (O.S.G. Pauwels), Natural History Muaeum London (S. Loader), University of the Cape (Prof. Dr. A. Channing, M. Burger), Port Elizabeth Museum (Dr. W.R. Branch)

Ecology: University of Ulm (J. Fahr, community ecology), Geneva Botanical Garden (Dr. C. Chatelain, habitat fragmentation), University of Halifax (Prof. Dr. R. Wassersug, tadpole ecology), University of Virginia (V. Rudolf, phenotypic plasticity), University of Vermont (Dr. J. Decher, community ecology), University of Karlsruhe (Prof. Dr. A. Martens, community ecology), University of Philadelphia (F. Range) and University of Strasbourg (Prof. Dr. R. Noë, predator-prey relationships)

Genetics: University of Mainz (PD M. Veith, J. Kosuch)

Conservation: IUCN (Global Amphibian Assessment, Dr. S. Stuart), Conservation International (Rapid Assessment Program, Dr. Leeanne Alonso), Afrique Nature (Dr. F. Lauginie), Guyana Forestry Commission (Dr. R. Thomas), Durrel Foundation (Jersey Zoo)

Capacity building: University of Abobo-Ajamé, Abidjan (Dr. J. Tondoh, Dr. S. Konaté), University of Cocody, Abidjan (Dr. K. Inza), University of Cotonou (Prof. Dr. B. Sinsin), University of Conakry (Dr. P. Condé), University of Guyana, University of Antananarivo (Prof. Dr. D. Raktondravony)

Publications: PR = peer reviewed, NPR = not peer reviewed

Fig. 1: West African sites with known amphibian assemblages. Given is the level of endemism for every site (% of species, species number per site: range 9-87). Level 1= species occurs also outside West Africa; level 2: occurs only in West Africa (Senegal to eastern Nigeria); level 3: occurs only East of Dahomey gap (natural forest gap between eastern Ghana et Benin); level 4: occurs only West of Dahomey gap (Upper Guinea forests); level 5: occurs only in part of the Upper Guinean forest (e.g. western Ivory Coast to Sierra Leone); level 6: are local endemics (e.g. only on Monts Nimba, Taï National Park). Highest percentage of endemic species is found in the Upper Guinea forests. The Upper Guinea highlands (i.e. Monts Nimba, Pic de Fon), Taï National Park and eastern Upper Guinea forests have the highest percentage of local endemics. Species (read from top left to bottom right): Nimbaphrynoides occidentalis (endemic to montane grassland on Mont Nimba), Kassina lamottei (endemic to forests in south-western Ivory Coast); Kassina senegalensis (savannahs in sub-Saharan Africa); Phlyctimantis boulengeri (secondary forests of western Africa).