@article{EccardLiesenjohannDammhahn2020,
  author    = {Eccard, Jana and Liesenjohann, Thilo and Dammhahn, Melanie},
  title     = {Among-individual differences in foraging modulate resource exploitation under perceived predation risk},
  series = {Oecologia},
  volume    = {194},
  journal   = {Oecologia},
  number    = {4},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {0029-8549},
  doi       = {10.1007/s00442-020-04773-y},
  pages     = {621 -- 634},
  year      = {2020},
  abstract  = {Foraging is risky and involves balancing the benefits of resource acquisition with costs of predation. Optimal foraging theory predicts where, when and how long to forage in a given spatiotemporal distribution of risks and resources. However, significant variation in foraging behaviour and resource exploitation remain unexplained. Using single foragers in artificial landscapes of perceived risks and resources with diminishing returns, we aimed to test whether foraging behaviour and resource exploitation are adjusted to risk level, vary with risk during different components of foraging, and (co)vary among individuals. We quantified foraging behaviour and resource exploitation for 21 common voles (Microtus arvalis). By manipulating ground cover, we created simple landscapes of two food patches varying in perceived risk during feeding in a patch and/or while travelling between patches. Foraging of individuals was variable and adjusted to risk level and type. High risk during feeding reduced feeding duration and food consumption more strongly than risk while travelling. Risk during travelling modified the risk effects of feeding for changes between patches and resulting evenness of resource exploitation. Across risk conditions individuals differed consistently in when and how long they exploited resources and exposed themselves to risk. These among-individual differences in foraging behaviour were associated with consistent patterns of resource exploitation. Thus, different strategies in foraging-under-risk ultimately lead to unequal payoffs and might affect lower trophic levels in food webs. Inter-individual differences in foraging behaviour, i.e. foraging personalities, are an integral part of foraging behaviour and need to be fully integrated into optimal foraging theory.},
  language  = {en}
}
@misc{MendesFerreiraDammhahnEccard2022,
  author    = {Mendes Ferreira, Clara and Dammhahn, Melanie and Eccard, Jana},
  title     = {Forager-mediated cascading effects on food resource species diversity},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {1312},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-58509},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-585092},
  pages     = {13},
  year      = {2022},
  abstract  = {Perceived predation risk varies in space and time. Foraging in this landscape of fear alters forager-resource interactions via cascading nonconsumptive effects. Estimating these indirect effects is difficult in natural systems. Here, we applied a novel measure to quantify the diversity at giving-up density that allows to test how spatial variation in perceived predation risk modifies the diversity of multispecies resources at local and regional spatial levels. Furthermore, we evaluated whether the nonconsumptive effects on resource species diversity can be explained by the preferences of foragers for specific functional traits and by the forager species richness. We exposed rodents of a natural community to artificial food patches, each containing an initial multispecies resource community of eight species (10 items each) mixed in sand. We sampled 35 landscapes, each containing seven patches in a spatial array, to disentangle effects at local (patch) and landscape levels. We used vegetation height as a proxy for perceived predation risk. After a period of three nights, we counted how many and which resource species were left in each patch to measure giving-up density and resource diversity at the local level (alpha diversity) and the regional level (gamma diversity and beta diversity). Furthermore, we used wildlife cameras to identify foragers and assess their species richness. With increasing vegetation height, i.e., decreasing perceived predation risk, giving-up density, and local alpha and regional gamma diversity decreased, and patches became less similar within a landscape (beta diversity increased). Foragers consumed more of the bigger and most caloric resources. The higher the forager species richness, the lower the giving-up density, and alpha and gamma diversity. Overall, spatial variation of perceived predation risk of foragers had measurable cascading effects on local and regional resource species biodiversity, independent of the forager species. Thus, nonconsumptive predation effects modify forager-resource interactions and might act as an equalizing mechanism for species coexistence.},
  language  = {en}
}
@article{MendesFerreiraDammhahnEccard2022,
  author    = {Mendes Ferreira, Clara and Dammhahn, Melanie and Eccard, Jana},
  title     = {Forager-mediated cascading effects on food resource species diversity},
  series = {Ecology and Evolution},
  volume    = {12},
  journal   = {Ecology and Evolution},
  number    = {11},
  publisher = {John Wiley \& Sons},
  issn      = {2045-7758},
  doi       = {10.1002/ece3.9523},
  pages     = {13},
  year      = {2022},
  abstract  = {Perceived predation risk varies in space and time. Foraging in this landscape of fear alters forager-resource interactions via cascading nonconsumptive effects. Estimating these indirect effects is difficult in natural systems. Here, we applied a novel measure to quantify the diversity at giving-up density that allows to test how spatial variation in perceived predation risk modifies the diversity of multispecies resources at local and regional spatial levels. Furthermore, we evaluated whether the nonconsumptive effects on resource species diversity can be explained by the preferences of foragers for specific functional traits and by the forager species richness. We exposed rodents of a natural community to artificial food patches, each containing an initial multispecies resource community of eight species (10 items each) mixed in sand. We sampled 35 landscapes, each containing seven patches in a spatial array, to disentangle effects at local (patch) and landscape levels. We used vegetation height as a proxy for perceived predation risk. After a period of three nights, we counted how many and which resource species were left in each patch to measure giving-up density and resource diversity at the local level (alpha diversity) and the regional level (gamma diversity and beta diversity). Furthermore, we used wildlife cameras to identify foragers and assess their species richness. With increasing vegetation height, i.e., decreasing perceived predation risk, giving-up density, and local alpha and regional gamma diversity decreased, and patches became less similar within a landscape (beta diversity increased). Foragers consumed more of the bigger and most caloric resources. The higher the forager species richness, the lower the giving-up density, and alpha and gamma diversity. Overall, spatial variation of perceived predation risk of foragers had measurable cascading effects on local and regional resource species biodiversity, independent of the forager species. Thus, nonconsumptive predation effects modify forager-resource interactions and might act as an equalizing mechanism for species coexistence.},
  language  = {en}
}
@article{EccardMendesFerreiraPeredoArceetal.2022,
  author    = {Eccard, Jana and Mendes Ferreira, Clara and Peredo Arce, Andres and Dammhahn, Melanie},
  title     = {Top-down effects of foraging decisions on local, landscape and regional biodiversity of resources (DivGUD)},
  series = {Ecology letters},
  volume    = {25},
  journal   = {Ecology letters},
  number    = {1},
  publisher = {Wiley-Blackwell},
  address   = {Oxford [u.a.]},
  issn      = {1461-0248},
  doi       = {10.1111/ele.13901},
  pages     = {3 -- 16},
  year      = {2022},
  abstract  = {Foraging by consumers acts as a biotic filtering mechanism for biodiversity at the trophic level of resources. Variation in foraging behaviour has cascading effects on abundance, diversity, and functional trait composition of the community of resource species. Here we propose diversity at giving-up density (DivGUD), i.e. when foragers quit exploiting a patch, as a novel concept and simple measure quantifying cascading effects at multiple spatial scales. In experimental landscapes with an assemblage of plant seeds, patch residency of wild rodents decreased local alpha-DivGUD (via elevated mortality of species with large seeds) and regional gamma-DivGUD, while dissimilarity among patches in a landscape (beta-DivGUD) increased. By linking theories of adaptive foraging behaviour with community ecology, DivGUD allows to investigate cascading indirect predation effects, e.g. the ecology-of-fear framework, feedbacks between functional trait composition of resource species and consumer communities, and effects of inter-individual differences among foragers on the biodiversity of resource communities.},
  language  = {en}
}