The Role of Local and Regional Processes along the Gradients of Habitat Specialization from a Metacommunity Perspective

Emergence of the metacommunity concept has explicitly recognized the interplay of local and regional processes. The metacommunity concept has already made a substantial contribution to the better understanding of the community composition and dynamics in a regional context. However, long-term field data for testing of available metacommunity models are still scarce and the extent to which these models apply to the real world remains unknown and some of their assumptions untested. Tests conducted so far have largely sought to fit data on the entire regional set of species to one of several metacommunity models, implicitly assuming that all species, members of the metacommunity, can be modelled in the same manner (using a single model). However, species differ in their habitat use to the extent that such uniform treatment may be inappropriate. Furthermore, in testing the metacommunity models, all metacommunity studies relay on snapshots of species distribution to assess the relative importance of local and regional processes. However, snapshot patterns may be insufficient for producing a reliable picture of metacommunity dynamics and processes shaping it. I hypothesised that the relative importance of local (competition, predation or abiotic filtering or constraints) and regional (interaction of populations with landscape, migration or dispersal) processes may vary with species' traits, including habitat specialization. The perception of importance of local and regional processes in structuring community composition obtained via static approach may vary from that obtained by considering the temporal dynamics of component species. My general approach used a model system comprising natural rock pools microcosms. I have also employed experimental approach in the laboratory. I found that different metacommunity models suit for different groups of habitat specialization. I also found this to be true whether the analyses are based on snapshot data or describing temporal dynamics of species populations. These results suggest that a metacommunity system exhibits an internal differentiation of structuring processes. Specifically, from the metacommunity perspective, the dynamics of habitat specialists are best explained by a combination of species sorting and mass effects models, while that of habitat generalists is best explained by patch dynamics and neutral models.

Department dc:contributor.department

Biology

Year dc:date.issued

2009

Author dc:creator

• Pandit, Shubha N.

Advisor dc:contributor.advisor

• Kolasa, Jurek

• biology, habitat specialization, habitat generalists, habitat specialists, population synchrony, temporal turnover, metacommunity

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/11375/17377

OAI record oai:identifier

https://macsphere.mcmaster.ca/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Amacsphere.mcmaster.ca%3A11375%2F17377