Abstract
Detailed information about three-dimensional vegetation structure proves
increasingly useful for studying species-habitat relationships in
forest ecosystems. This particularly applies to species that make
extensive use of the three-dimensional habitat space in forests, such as
bats. Bats show considerable variation in flight morphology and
echolocation traits that are shaped by habitat features, and are
excellent model taxa for investigating relationships between vegetation
structure and animal occurrence and movement. The aims of this study
were (1) to investigate the relationship between the activity of bats
and forest structure and (2) to compare the performance of airborne
Light Detection and Ranging (LiDAR) and terrestrial field surveys for
measuring habitat features in a representative sample of mixed and
deciduous forests in the Swiss lowlands. Leaf-on and leaf-off LiDAR data
were used separately, as well as in combination, to evaluate the
relative strength of these datasets to describe 3D canopy architecture
and vertical forest structure. Field measurements included structural
variables such as leaf area index (LAI), vertical layering, snags, as
well as shrub and ground vegetation cover. We recorded 145,433
echolocation call sequences from bats and assigned them into three
echolocation guilds (short-, mid- and long-range echolocators; SRE, MRE,
LRE, respectively) treating separately the dominant species (Pipistrellus pipistrellus;
Pp). We used generalized linear mixed models (GLMMs) and applied an
information-theoretic approach to assess relationships between
guild-specific activity patterns of bats and forest structure in the
forest interior, as well as in forest gaps. Standardized coefficients
were used to evaluate variable effect sizes and relative importance. We
found that guild-specific bat activity was clearly related to 3D forest
structure. The activity of SRE, MRE and Pp bats was negatively affected
by foliage height diversity, indicating that a large scatter of
vegetation elements along 3D forest profiles may restrict accessibility
for manoeuvrable bats. Outer canopy surface ruggedness was significantly
and positively related to the activity of MRE and LRE bats, as well as
Pp, all of which may profit from increased canopy surface ruggedness for
foraging (food abundance) and commuting (cover) purposes. The highest
variable effect sizes were obtained by combining leaf-on and leaf-off
LiDAR data. Leaf-off outperformed leaf-on data, particularly in
describing foliage height diversity. LiDAR provided information about
bat habitat structure in forests that is not readily available from
field surveys. LiDAR thus increases the scope of inference for future
investigations of how species respond to vegetation structure, which can
now readily and contiguously be assessed at relevant grain sizes and
across large areas.
Original language | English |
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Pages (from-to) | 242-250 |
Number of pages | 8 |
Journal | Remote Sensing of Environment |
Volume | 175 |
Early online date | 17 Jan 2016 |
DOIs | |
Publication status | Published - Mar 2016 |
Keywords
- Bat
- LiDAR
- Field surveys
- Bioacoustics
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Professor Gareth Jones
- Cabot Institute for the Environment
- Bristol Neuroscience
- School of Biological Sciences - Professor of Biological Sciences
- Evolutionary Biology
- Animal Behaviour and Sensory Biology
Person: Academic , Member