. From field surveys to LiDAR: Shining a light on how bats respond to forest structure. Remote Sensing of Environment, 175, 242-250. DOI: 10.1016/j.rse.2015 Peer reviewed version Link to published version (if available): 10.1016/j.rse. 2015.12.038 Link to publication record in Explore Bristol Research PDF-document This is the author accepted manuscript (AAM). The final published version (version of record) is available online via Elsevier at http://www.sciencedirect.com/science/article/pii/S0034425715302601. University of Bristol -Explore Bristol Research General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Detailed information about three-dimensional vegetation structure proves increasingly useful for 25 studying species-habitat relationships in forest ecosystems. This particularly applies to species that 26 make extensive use of the three-dimensional habitat space in forests, such as bats. Bats show 27 considerable variation in flight morphology and echolocation traits that are shaped by habitat features, 28 and are excellent model taxa for investigating relationships between vegetation structure and animal 29 occurrence and movement. The aims of this study were (1) to investigate the relationship between the 30 activity of bats and forest structure and (2) to compare the performance of airborne Light Detection 31 and Ranging (LiDAR) and terrestrial field surveys for measuring habitat features in a representative 32 sample of mixed and deciduous forests in the Swiss lowlands. Leaf-on and leaf-off LiDAR data were 33 used separately, as well as in combination, to evaluate the relative strength of these datasets to 34 describe 3D canopy architecture and vertical forest structure. Field measurements included structural 35 variables such as leaf area index (LAI), vertical layering, snags, as well as shrub and ground 36 vegetation cover. We recorded 145,433 echolocation call sequences from bats and assigned them into 37 three echolocation guilds (short-, mid-and long-range echolocators; SRE, MRE, LRE, respectively) 38 treating separately the dominant species (Pipistrellus pipistrellus; Pp). We used Generalized Mixed 39Effects Models (GLMMs) and applied an information-theoretic approach to assess relationships 40 between guild-specific activity patterns of bats and forest structure in the forest interior, as well as in 41 forest gaps. Standardized coefficients were used to evaluate variable effect sizes and relative 42 importance. We found that guild-specific bat activity was clearly related to three-dimensional forest 43 structure. The activity of SRE, MRE and Pp bats was negatively affected by foliage height diversity, 44indicating that a large scatter of vegetation elements along 3D forest profiles may restrict accessibility 45 for manoeuvrable bats. Outer canopy surface ruggedness was significantly and positively related to 46 the activity of MRE and LRE bats, as well as Pp, all of which may profit from increased...

Passive acoustic methods are increasingly used in biodiversity research and monitoring programs because they are cost-effective and permit the collection of large datasets. However, the accuracy of the results depends on the bioacoustic characteristics of the focal taxa and their habitat use. In particular, this applies to bats which exhibit distinct activity patterns in three-dimensionally structured habitats such as forests. We assessed the performance of 21 acoustic sampling schemes with three temporal sampling patterns and seven sampling designs. Acoustic sampling was performed in 32 forest plots, each containing three microhabitats: forest ground, canopy, and forest gap. We compared bat activity, species richness, and sampling effort using species accumulation curves fitted with the clench equation. In addition, we estimated the sampling costs to undertake the best sampling schemes. We recorded a total of 145,433 echolocation call sequences of 16 bat species. Our results indicated that to generate the best outcome, it was necessary to sample all three microhabitats of a given forest location simultaneously throughout the entire night. Sampling only the forest gaps and the forest ground simultaneously was the second best choice and proved to be a viable alternative when the number of available detectors is limited. When assessing bat species richness at the 1-km2 scale, the implementation of these sampling schemes at three to four forest locations yielded highest labor cost-benefit ratios but increasing equipment costs. Our study illustrates that multiple passive acoustic sampling schemes require testing based on the target taxa and habitat complexity and should be performed with reference to cost-benefit ratios. Choosing a standardized and replicated sampling scheme is particularly important to optimize the level of precision in inventories, especially when rare or elusive species are expected.

HighlightsOrganic farming promotes arachnids but is ineffective on its own for bats in Mediterranean vineyards.Agri-environment schemes are not most effective for bats in landscapes of intermediate complexity.Bat activity was positively associated with proximity to hedgerows and rivers.A multi-scale approach is required to design adequate conservation strategies.