Mountain Biodiversity; ferns; Island Biogeography; pteridophytes; biodiversity; spatial scale
Karger Dirk Nikolaus, Cord Anna F., Kessler Michael, Kreft Holger, Kühn Ingolf, Pompe Sven, Sandel Brody, Sarmento Cabral Juliao, Smith Adam .B., Svenning Jens-Christian, Tuomisto Hanna, Weigelt Patrick, Wesche Karsten (2016), Delineating probabilistic species pools in ecology and biogeography, in Global Ecology and Biogeography
Weigelt Patrick, Kissling W. Daniel, Kisel Yael, Fritz Susanne A., Karger Dirk Nikolaus, Kessler Michael, Lehtonen Samuli, Svenning Jens-Christian, Kreft Holger (2015), Global patterns and drivers of phylogenetic structure in island floras, in Scientific Reports
, 5, 12213.
Karger Dirk Nikolaus, Tuomisto Hanna, Amoroso Victor B., Darnaedi Dedy, Hidayat Arief, Abrahamczyk Stefan, Kluge Jürgen, Lehnert Marcus, Kessler Michael, The importance of species pool size for community composition, in Ecography
What determines species diversity? This question has troubled researchers for centuries and has yet to be answered. One of the most prominent patterns of species diversity is the latitudinal gradient in species diversity from the polar region towards the tropics. For most major groups of terrestrial organisms, diversity is highest in the tropics. Yet, the factors determining this high tropical diversity remain elusive. This is partly due to the large number of potential explanatory factors that often co-vary and the wide extent of the latitudinal gradient. Yet another problem in disentangling the processes driving species diversity along the latitudinal gradient arises from the scale dependence of factors driving species diversity. In the proposed project I want to account for this scale dependence of diversity by studying changes in community composition (ß diversity). ß-diversity links regional to local scales of diversity and gives insight into the fundamental processes that drive and maintain biodiversity. It has been hypothesized that ß-diversity along the latitudinal gradient is due to differences in local community assembly at different latitudes. An alternative hypothesis states that the decline of ß-diversity along the latitudinal gradient is due to differences in the size of the species pool of the focal communities, and that the fundamental processes driving community assembly are the same. During my Ph.D. I gained evidence that the degree to which local processes explain ß-diversity strongly depends on the size of the regional (large scale) species pool and processes therein. Based on this observation, I aim to show that the same community assembly processes drive ß diversity, but that their strength varies significantly across spatial scales, and that this resulted in the different hypothesis about community assembly along the latitudinal gradient. This would combine the above mentioned hypotheses and provide an explanation on what drives ß-diversity variation along the latitudinal gradient.I will do so by showing that the interpretation of mechanisms driving ß-diversity depends on spatial scale, by sampling fern diversity along the latitudinal gradient at different spatial scales. By this I also want to show that drivers of ß-diversity are scale-dependent along the latitudinal gradient, by investigating fern species richness along a latitudinal gradient from Japan across Taiwan, Hainan (China) and the Philippines to Indonesia.Answering this question will help us to understand what determines ß-diversity across spatial scales and will have an important impact on linking macroecological, and phylogeographical patterns of species diversity with local ecology. There are only a few studies that have attempted to incorporate spatial scale in empirical studies of biodiversity, but none so far for species composition (ß diversity). Although there has been recent theoretical work on the influence of spatial scale on ß diversity, evaluating such concepts using empirical data will be a groundbreaking contribution to biodiversity research.