A Phylogenetic Perspective on the Individual Species-Area Relationship in Temperate and Tropical Tree Communities

<div><p>Ecologists have historically used species-area relationships (SARs) as a tool to understand the spatial distribution of species. Recent work has extended SARs to focus on individual-level distributions to generate individual species area relationships (ISARs). The ISAR approach quantifies whether individuals of a species tend have more or less species richness surrounding them than expected by chance. By identifying richness ‘accumulators’ and ‘repellers’, respectively, the ISAR approach has been used to infer the relative importance of abiotic and biotic interactions and neutrality. A clear limitation of the SAR and ISAR approaches is that all species are treated as evolutionarily independent and that a large amount of work has now shown that local tree neighborhoods exhibit non-random phylogenetic structure given the species richness. Here, we use nine tropical and temperate forest dynamics plots to ask: (<i>i</i>) do ISARs change predictably across latitude?; (<i>ii</i>) is the phylogenetic diversity in the neighborhood of species accumulators and repellers higher or lower than that expected given the observed species richness?; and (<i>iii</i>) do species accumulators, repellers distributed non-randomly on the community phylogenetic tree? The results indicate no clear trend in ISARs from the temperate zone to the tropics and that the phylogenetic diversity surrounding the individuals of species is generally only non-random on very local scales. Interestingly the distribution of species accumulators and repellers was non-random on the community phylogenies suggesting the presence of phylogenetic signal in the ISAR across latitude.</p></div

The phylogenetic signal of species diversity accumulators and repellers on each scale from 0–50 m in the nine forest dynamics plots, using D statistic developed by Fritz and Purvis (2010).

<p>Grey horizontal lines represent random expectation (D = 1) and Brownian expectation (D = 0).</p

Proportion of significant species diversity accumulators, repellers and neutral species for the species with individuals ≥1 cm dbh in the nine plots.

<p>Proportion of significant species diversity accumulators, repellers and neutral species for the species with individuals ≥1 cm dbh in the nine plots.</p

Proportion of phylogenetic diversity accumulators, repellers and neutral species for the species with individuals ≥1 cm dbh in the nine plots.

<p>Proportion of phylogenetic diversity accumulators, repellers and neutral species for the species with individuals ≥1 cm dbh in the nine plots.</p

Proportion of species diversity accumulators, repellers and neutral species for the species having ≥70 individuals ≥1 cm in the nine plots.

<p>Proportion of species diversity accumulators, repellers and neutral species for the species having ≥70 individuals ≥1 cm in the nine plots.</p

Proportion of phylogenetic diversity accumulators, repellers and neutral species for the species having ≥70 individuals ≥1 cm in the nine plots.

<p>Proportion of phylogenetic diversity accumulators, repellers and neutral species for the species having ≥70 individuals ≥1 cm in the nine plots.</p

Additional file 2: of GWASeq: targeted re-sequencing follow up to GWAS

Regional plots of associations for each targeted region. rs numbers and purple circles indicate the focal GWAS SNP that the region was selected around. Colored circles indicate degree of LD among SNPs. Grey circles indicate novel SNPs that lack LD information based on the 2012 release of the 1000 Genomes data. The rs number at figure top is centered around the location of the focal SNP. (ZIP 1921 kb

Additional file 1: of GWASeq: targeted re-sequencing follow up to GWAS

Boxplot of per-sample coverage by region, for each of the sequenced regions, by case–control status. (TIFF 8219 kb