DOI: 10.5061/dryad.12jm63z02
title: Habitat area and environmental filters determine avian richness along an elevation gradient in mountain peatlands

description: Globally, relationships between avian richness and elevation in mountain
 ecosystems typically reflect one of four well-documented patterns, but the
 mechanisms responsible for these patterns are poorly understood. We
 investigated which pattern best described bird species richness in
 peatlands of the Upper Bow Basin of the Canadian Rocky Mountains (1300 to
 2000 m a.s.l.) and used a model competition framework to investigate
 possible mechanisms. Avian richness displayed a plateauing (cubic)
 relationship in response to increasing elevation (AICc weight = 0.48). Log
 richness was significantly positively related to log peatland area (R2 =
 0.42, p = 0.001); however, once we accounted for the richness-area
 relationship (area was not related to elevation (R2 = 0.13, p = 0.083)),
 the richness-elevation relationship was best described by a negative
 linear model rather than a cubic model (AICc weight = 0.69, R2 = 0.39).
 Consequently, we reject the neutral model of the mid-domain effect and
 conclude that peatland area and one or more environmental filters are
 simultaneously driving relationships between avian richness and elevation
 in Rocky Mountain peatlands. Multi-causality likely explains why
 researchers in different geographies observe inconsistent patterns between
 richness and elevation: drivers and interactions among drivers may vary
 spatially. Importantly, Natural Subregion was a stronger predictor of
 avian species richness than elevation per se (AICc weight = 0.96),
 suggesting that the responsible environmental filter(s) is relatively
 homogenous within ecological land classes (e.g., primary productivity)
 rather than directly variable with elevation (e.g., temperature). The
 results also lend insight into priorities for future research on
 richness-elevation patterns in mountain birds.
description: Data was collected from 24 peatlands situated in the Upper Bow
 River Basin on the eastern slopes of the Rocky Mountains across a range of
 elevation. Avian diversity was determined from transcriptions of
 recordings made with SM4 Automated Recording Units deployed in May 2019
 and collected in June 2019. Details are published in the associated
 manuscript published in the article "Habitat area and environmental
 filters determine avian richness along an elevation gradient in mountain
 peatlands" published in the Journal of Avian Biology and in the 2020
 MSc. thesis by Jordan Reynolds from the University of Waterloo, titled
 "Avian species richness elevational patterns in mountain
 peatlands." This thesis can be accessed for free online
 at https://uwspace.uwaterloo.ca/handle/10012/16127. The attached files
 have a tab of data and a second tab describing the column headings, which
 provide descriptions of how data were treated.
description: There are no readme files. There are no missing data. There are
 three excel files with two worksheets in each. the first gives the data
 and the second provides a description of the data or definition of the
 column headings in the first worksheet. One worksheet gives the avian
 richness, size, elevation, and site ID for each peatland. The second gives
 the presence-absence data for all detected bird species at each peatland.
 The third characterizes the species accumulation curve for each peatland
 to contextualize the sufficiency of our sampling effort.