Long-term community dynamics
Tropical forests harbor a stunning biological diversity, and the question of the origins and maintenance of this diversity is a central topic in modern ecology. A large proportion of the plant and animal species are found in the forest canopy, and any general theory on biodiversity and community assembly should thus be applicable to canopy-dwelling organisms such as vascular epiphytes. Is community assembly a deterministic process or largely a matter of chance? This central question is addressed in an on-going study financed by the Deutsche Forschungsgemeinschaft, which consists of both descriptive and experimental elements. Taking advantage of initial census work more than a decade ago, we no directly document temporal and spatial dynamics of complex epiphyte communities and use transplant and ecophysiological experiments to come to a mechanistic understanding of the processes that allow for the co-occurrence of up to 80 epiphyte species on a single tree. Access is possible by either studying epiphytes on host trees of small stature (Annona glabra) or by the use of a tower crane in primary lowland forest. The first site is located in the Barro Colorado Nature Monument, the second is near San Lorenzo in Panama. Both sites are administered by the Smithsonian Tropical Research Institute. Information on the crane site can be found here.
Burns KC & Zotz G. 2010. A hierarchical framework for investigating epiphyte assemblages: networks, metacommunities and Scale. Ecology 91: 377-385.
Zotz G & Schultz S. 2008. The vascular epiphytes of a lowland forest in Panama - species composition and spatial structure. Plant Ecology 195: 131-141.
Zotz G. 2007. The population structure of the vascular epiphytes in a lowland forest in Panama correlates with species abundance. Journal of Tropical Ecology 23: 337-342.
Laube S & Zotz G. 2007. A metapopulation approach to the analysis of long-term changes in the epiphyte vegetation on the host tree Annona glabra. Journal of Vegetation Science 18: 613-624.
Laube S & Zotz G. 2006. Long-term changes in the epiphyte vegetation of the palm, Socratea exorrhiza. Journal of Vegetation Science 17: 307-314.
Zotz G. 2004. How prevalent is crassulacean acid metabolism among vascular epiphytes? Oecologia 138: 184-192.
Zotz G, Bermejo P & Dietz H. 1999. The epiphyte vegetation of Annona glabra on Barro Colorado Island, Panama. Journal of Biogeography 26: 761-776.