10.5061/DRYAD.2Z34TMPNB
Jankowski, Jill
0000-0003-3273-1388
University of British Columbia
Kyle, Keiller
The Nature Conservancy
Gasner, Matthew
Nature Conservancy of Canada
Ciecka, Anna
Western EcoSystems Technology
Rabenold, Kerry
Purdue University
Response of Avian communities to edges of tropical montane forests:
Implications for the future of endemic habitat specialists
Dryad
dataset
2021
FOS: Biological sciences
National Aeronautics and Space Administration
https://ror.org/027ka1x80
Purdue University West Lafayette
https://ror.org/02dqehb95
American Ornithological Society
https://ror.org/03wy7n216
2021-09-02T00:00:00Z
2021-09-02T00:00:00Z
en
29508 bytes
2
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Tropical montane landscapes harbor diverse flora and fauna, and many
species there are ecological specialists with narrow elevational
distributions, limited geographic ranges, and small global populations.
Along elevational gradients, environmental conditions and community
composition change dramatically over small spatial scales. As forests are
disturbed and edges formed with modified habitat, natural communities
could be affected differently across elevations by the many physical and
biotic changes at edges. We asked whether forest edges produced altered
patterns of avian species composition along a cloud forest - dry forest
gradient on the Pacific slope of the Tilarán mountains in Monteverde,
Costa Rica. A strong moisture gradient produces cloud forests near the
ridgetops, with a concentration of species endemic to the Costa Rica –
Panama highlands that are habitat specialists. We conducted 552 point
counts across 110 locations from 1100 to 1800 m elevation, yielding 6586
detections of 115 species in 10 km2 of montane forest. We analyzed
differences in species composition and single-species abundances between
interior and near-edge forest habitats for species grouped by geographic
range size. Species composition changed markedly from forest edge to
interior in cloud forest habitats, but not in drier forests
downslope. Endemic species, especially in cloud forest, were detected less
frequently in mature forest near edges than in mature forest interior, and
this difference was more pronounced than for cosmopolitan species. On
tropical mountainsides, we can expect habitat-specialist endemic species
to be more sensitive to further habitat modification. This sensitivity
could limit the resilience of tropical bird communities.
These data come from audio-visual surveys (point counts) conducted in
May-July (the avian breeding season) of 2006 from 1100-1800 m elevation,
at 110 points, including 77 points located in forest interior and 33
points near forest edges. Points were separated by >200 m to avoid
double counting individuals across points, and were distributed across a
moisture gradient defined by the distance of points to the continental
divide. Edge points were placed inside the forest 50 m from a boundary
with a clearing to keep the sampled area within forest. Interior points
were placed >200 m from a boundary. All birds seen or heard in 10
min within a 50 m radius by two observers were recorded with the estimated
distance of detection. Counts were repeated at each point weekly, a total
of five times over the season (see published article for further
details). We used the maximum number of simultaneously detected
conspecifics per point across all visits for each species’ abundance value
at each point, and created a site by species matrix using these values.
The dataset provided shows the site by species matrix, with sites (point
labels="SITE") as rows, and associated point data (distance of
point from the continental divide in meters = "DTD"; elevation
of point in m.a.s.l. = "ELEV"; categorical zone of distance from
the continental divide = "DTD_ZONE"; categorical variable
labeling each site as a forest dge or interior point =
"INT-EDG"; zone-habitat as a merged column of DTD_ZONE and
INT-EDG = "ZONE_HAB") and the remaining columns as species
(shown by each species' letter code). Values in the data matrix show
the maximum number of simultaneously detected individuals of a species at
a point over the five visits to the site. A table of letter codes of
species corresponding to the columns of this data matrix can be found in
Table A2 of published Supplementary Material.