
Which dimension of biodiversity best captures the processes structuring this Costa Rican lichen community: species identity, traits, or ancestry? The clearest picture may come from considering all three.
Pavoine and Bonsall’s paper about community assembly is a beast. It’s big (26 pages), it’s scary (only two of those pages are figures), and it wants to eat your morning. But, there are three good reasons to read beyond the page-long abstract and table of contents, whether or not you believe that traits and phylogenies are ecology’s salvation.
Read it for the tables. I never thought I’d say this about anything, but the best part about this paper is its tables. As a reference of biodiversity indices they are invaluable- Who’s responsible for the phylogenetic diversity index that measures the mean distance to the nearest taxon? Webb (2000), Table 1. What is the analogous functional diversity index? Same table, same line. What explanations have folks given for high species richness combined with high phylogenetic diversity at the global scale? Look it up in Table 2. I could go on, but that might get tedious.
Read it to generate new ideas. The second half is filled with examples of how researchers have jointly analyzed patterns of taxonomic, functional and phylogenetic diversity to suggest which processes are driving diversity and structuring communities. Because processes relevant to communities depend on how communities are circumscribed, examples are explicitly organized by spatial scale- from local all the way up to global patterns. Graduate students with more “interest” than ideas could find lots of inspiration from the examples and suggestions provided here.
Read it to stave off cynicism. Inferring processes from patterns is a long-developed and highly criticized tradition in ecology and functional and phylogenetic diversity-based analyses are next in line to take the beating. The authors move beyond debates of null-models and over- / under-dispersion, to show why inference from diversity patterns is stronger when multiple dimensions are used together. Reading this paper renewed my sense that traits and phylogenies can be useful tools and that biodiversity patterns provide opportunities to refine hypotheses about what structures ecological communities.
Excellent choice, Jes, and great write-up. However, the idea that these different components can tell us anything meaningful about community assembly has come under attack. Jonathan Levine and Margaret Mayfield had an Ecology Letters publication in 2010 where they showed that competitive exclusion sometimes targets more or less related taxa (although we would otherwise infer environmental causes in former case). Moving forward, we will have to be very careful to not fall in this trap when inferring community assembly processes.
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