10.5061/DRYAD.3HG0054
Macchi, Leandro
Geography DepartmentHumboldt‐University Berlin Berlin Germany
Baumann, Matthias
Geography DepartmentHumboldt‐University Berlin Berlin Germany
Bluhm, Hendrik
Geography DepartmentHumboldt‐University Berlin Berlin Germany
Baker, Matthew
University of Maryland, Baltimore County
Levers, Christian
Geography DepartmentHumboldt‐University Berlin Berlin Germany
Grau, Héctor Ricardo
National Scientific and Technical Research Council
Kuemmerle, Tobias
Geography DepartmentHumboldt‐University Berlin Berlin Germany
Data from: Thresholds in forest bird communities along woody vegetation
gradients in the South American Dry Chaco
Dryad
dataset
2019
critical thresholds
continuous vegetation cover
Forest bird community
2019-02-19T14:23:38Z
2019-02-19T14:23:38Z
en
https://doi.org/10.1111/1365-2664.13342
12820 bytes
1
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
1. Worldwide, tropical savannas and dry forests are under increasing
pressure from land use. The environmental impacts of agricultural
expansion into these ecosystems have received much attention, yet subtler
changes in natural vegetation remain severely understudied. 2. We explored
how bird communities vary along gradients of woody vegetation in the South
American Dry Chaco by combining high-resolution, satellite-based tree,
shrub, and total woody cover with field data on the frequency of 82 bird
species surveyed in 167 plots. We identified change points along woody
cover gradients where the relative frequency of individual bird species
dropped most strongly. Based on this, we identified forest indicator
species and assessed evidence for community-level thresholds. 3. Most
forest birds (71%) had clear change points in their frequencies along
vegetation gradients, starting as high as 38% total woody cover. Many
(41%) forest species declined drastically at woody cover levels of less
than 11%. This general pattern was similar for tree and shrub cover. 4.
Only 7% of our study area had woody cover levels where we detected no
response in forest bird communities. In contrast, 68% of the area had
woody cover levels with incremental declines in forest bird species, and
25% of the study area had woody cover levels below the forest bird
community threshold. 5. We identified eleven indicator species strongly
related to woody cover, with highest frequencies in the eastern and
western Dry Chaco. Spatial distributions of these species corresponded
well with areas above and below woody vegetation thresholds. 6. Synthesis
and applications. We found evidence for critical thresholds for forest
birds along woody cover gradients in dry forests, and implemented tools to
map where these thresholds have been crossed. For the Chaco, we highlight
the importance of maintaining woody cover levels above about 40%, such as
in certain silvopastoral systems that can be much more wildlife-friendly
than other forms of agriculture. We identify remaining areas of
potentially intact forest bird communities. More broadly, this study
highlights the value of combining species-level (indicator species’
distributions) and ecosystem-level (satellite-based, continuous woody
cover maps) surrogates for understanding biodiversity patterns and
threats.
birds, shrub cover, tree cover, total woody coverzip file contains for
each plot: birds relative frequency values, shrub/tree/total woody cover
valuesMacchi_JAPPL-2018-00109.R3.zip
Dry Chaco
South American Chaco