Remote sensing reveals the role of forage quality and quantity for summer habitat use in red deer
Abstract Background The habitat use of wild ungulates is determined by forage availability, but also the avoidance of predation and human disturbance. They should apply foraging strategies that provide the most energy at the lowest cost. However, due to data limitations at the scale of movement traj...
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BMC
2024-12-01
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| Series: | Movement Ecology |
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| Online Access: | https://doi.org/10.1186/s40462-024-00521-6 |
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| author | Thomas Rempfler Christian Rossi Jan Schweizer Wibke Peters Claudio Signer Flurin Filli Hannes Jenny Klaus Hackländer Sven Buchmann Pia Anderwald |
| author_facet | Thomas Rempfler Christian Rossi Jan Schweizer Wibke Peters Claudio Signer Flurin Filli Hannes Jenny Klaus Hackländer Sven Buchmann Pia Anderwald |
| author_sort | Thomas Rempfler |
| collection | DOAJ |
| description | Abstract Background The habitat use of wild ungulates is determined by forage availability, but also the avoidance of predation and human disturbance. They should apply foraging strategies that provide the most energy at the lowest cost. However, due to data limitations at the scale of movement trajectories, it is not clear to what extent even well-studied species such as red deer (Cervus elaphus) trade-off between forage quality and quantity, especially in heterogeneous alpine habitats characterized by short vegetation periods. Methods We used remote sensing data to derive spatially continuous forage quality and quantity information. To predict relative nitrogen (i.e. forage quality) and biomass (i.e. forage quantity), we related field data to predictor variables derived from Sentinel-2 satellite data. In particular, our approach employed random forest regression algorithms, integrating various remote sensing variables such as reflectance values, vegetation indices and optical traits derived from a radiative transfer model. We combined these forage characteristics with variables representing human activity, and applied integrated step selection functions to estimate sex-specific summer habitat selection of red deer in open habitats within and around the Swiss National Park, an alpine Strict Nature Reserve. Results The combination of vegetation indices and optical traits greatly improved predictive power in both the biomass (R2 = 0.60, Root mean square error (RMSE) = 88.55 g/m2) and relative nitrogen models (R2 = 0.34, RMSE = 0.28%). Both female and male red deer selected more strongly for biomass (estimate = 0.672 ± 0.059 SE for normalised values for females, and 0.507 ± 0.061 for males) than relative nitrogen (estimate = 0.124 ± 0.062 for females, and 0.161 ± 0.061 for males, respectively). Females showed higher levels of use of the Swiss National Park. Conclusions Red deer in summer habitats select forage quantity over quality with little difference between sexes. Females respond more strongly to human activities and thus prefer the Swiss National Park. Our results demonstrate the capability of satellite data to estimate forage quality and quantity separately for movement ecology studies, going beyond the exclusive use of conventional vegetation indices. |
| format | Article |
| id | doaj-art-d71adf02b13b4df4a1602f8da01c5960 |
| institution | OA Journals |
| issn | 2051-3933 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | BMC |
| record_format | Article |
| series | Movement Ecology |
| spelling | doaj-art-d71adf02b13b4df4a1602f8da01c59602025-08-20T02:31:55ZengBMCMovement Ecology2051-39332024-12-0112111510.1186/s40462-024-00521-6Remote sensing reveals the role of forage quality and quantity for summer habitat use in red deerThomas Rempfler0Christian Rossi1Jan Schweizer2Wibke Peters3Claudio Signer4Flurin Filli5Hannes Jenny6Klaus Hackländer7Sven Buchmann8Pia Anderwald9Department of Integrative Biology and Biodiversity Research, Institute of Wildlife Biology and Game Management, BOKU UniversitySwiss National Park, Chastè Planta-WildenbergSwiss National Park, Chastè Planta-WildenbergResearch Unit Wildlife Biology and Management, Bavarian State Institute of ForestryInstitute of Natural Resource Sciences, Wildlife Management Unit, Zurich University of Applied SciencesSwiss National Park, Chastè Planta-WildenbergCanton of Grisons, Hunting and Fisheries DepartmentDepartment of Integrative Biology and Biodiversity Research, Institute of Wildlife Biology and Game Management, BOKU UniversitySwiss National Park, Chastè Planta-WildenbergSwiss National Park, Chastè Planta-WildenbergAbstract Background The habitat use of wild ungulates is determined by forage availability, but also the avoidance of predation and human disturbance. They should apply foraging strategies that provide the most energy at the lowest cost. However, due to data limitations at the scale of movement trajectories, it is not clear to what extent even well-studied species such as red deer (Cervus elaphus) trade-off between forage quality and quantity, especially in heterogeneous alpine habitats characterized by short vegetation periods. Methods We used remote sensing data to derive spatially continuous forage quality and quantity information. To predict relative nitrogen (i.e. forage quality) and biomass (i.e. forage quantity), we related field data to predictor variables derived from Sentinel-2 satellite data. In particular, our approach employed random forest regression algorithms, integrating various remote sensing variables such as reflectance values, vegetation indices and optical traits derived from a radiative transfer model. We combined these forage characteristics with variables representing human activity, and applied integrated step selection functions to estimate sex-specific summer habitat selection of red deer in open habitats within and around the Swiss National Park, an alpine Strict Nature Reserve. Results The combination of vegetation indices and optical traits greatly improved predictive power in both the biomass (R2 = 0.60, Root mean square error (RMSE) = 88.55 g/m2) and relative nitrogen models (R2 = 0.34, RMSE = 0.28%). Both female and male red deer selected more strongly for biomass (estimate = 0.672 ± 0.059 SE for normalised values for females, and 0.507 ± 0.061 for males) than relative nitrogen (estimate = 0.124 ± 0.062 for females, and 0.161 ± 0.061 for males, respectively). Females showed higher levels of use of the Swiss National Park. Conclusions Red deer in summer habitats select forage quantity over quality with little difference between sexes. Females respond more strongly to human activities and thus prefer the Swiss National Park. Our results demonstrate the capability of satellite data to estimate forage quality and quantity separately for movement ecology studies, going beyond the exclusive use of conventional vegetation indices.https://doi.org/10.1186/s40462-024-00521-6BiomassCervus elaphusForaging ecologyHabitat selectionIntegrated step selection functionsNitrogen |
| spellingShingle | Thomas Rempfler Christian Rossi Jan Schweizer Wibke Peters Claudio Signer Flurin Filli Hannes Jenny Klaus Hackländer Sven Buchmann Pia Anderwald Remote sensing reveals the role of forage quality and quantity for summer habitat use in red deer Movement Ecology Biomass Cervus elaphus Foraging ecology Habitat selection Integrated step selection functions Nitrogen |
| title | Remote sensing reveals the role of forage quality and quantity for summer habitat use in red deer |
| title_full | Remote sensing reveals the role of forage quality and quantity for summer habitat use in red deer |
| title_fullStr | Remote sensing reveals the role of forage quality and quantity for summer habitat use in red deer |
| title_full_unstemmed | Remote sensing reveals the role of forage quality and quantity for summer habitat use in red deer |
| title_short | Remote sensing reveals the role of forage quality and quantity for summer habitat use in red deer |
| title_sort | remote sensing reveals the role of forage quality and quantity for summer habitat use in red deer |
| topic | Biomass Cervus elaphus Foraging ecology Habitat selection Integrated step selection functions Nitrogen |
| url | https://doi.org/10.1186/s40462-024-00521-6 |
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