. Bonner zoologische Monographien. Zoology. 15. : Interpreting idiosyncrasies and assessing the basis for nested distributions. The upper graph shows the nested distributions of 82 bat species (columns) at 19 sampling points (rows) along an elevational gradient in the Andes in southeastern Peru (Patterson et al. 1996). In this region, species richness of bats declines rapidly with elevation, and species do not generally replace one another along the gradient; higher-elevation communities are attenuated versions of those below. The temperature of this system is ° and the probability th
. Bonner zoologische Monographien. Zoology. 15. : Interpreting idiosyncrasies and assessing the basis for nested distributions. The upper graph shows the nested distributions of 82 bat species (columns) at 19 sampling points (rows) along an elevational gradient in the Andes in southeastern Peru (Patterson et al. 1996). In this region, species richness of bats declines rapidly with elevation, and species do not generally replace one another along the gradient; higher-elevation communities are attenuated versions of those below. The temperature of this system is ° and the probability that this could be due to chance is ~ 10"62. The lower graph shows the contrasting distributions of a handful of highland endemics, which appear as idiosyncratic "spikes" in the plot of species idiosyncrasies. The Spearman rank-correlation coefficient between rows (in the packed matrix) and elevation equals R = (P < ); nested structure may be plausibly attributed to elevation (or its correlates). Assessing causation The existence of strongly nested distributions suggests an universal ordering mechanism for species or sites in the system under study. However, the rows and columns of the matrix submitted to analysis have been rearranged in the packing step to maximize nestedness. Where are the matrix alterations recorded, and how can matrix order be compared to independently determined features? Matrix reorganization vectors record the rearrangements of rows and columns between matrices as submitted and those that emerged from the matrix-packing step. Descriptive vectors for either species or sites (, body size estimates of species or area estimates for sites) may then be compared to the order of each in the packed matrix. Because the ordering of species by the Nestedness Calculator is only relative, rank-correlation analysis of such variables is preferred (cf. Siegel 1956). Causal analyses are applied to two well-studied biogeographic systems. I
Size: 2282px × 1095px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodiversity, booksubjectzoology
