TY - JOUR A1 - Eccard, Jana A1 - Mendes Ferreira, Clara A1 - Peredo Arce, Andres A1 - Dammhahn, Melanie T1 - Top-down effects of foraging decisions on local, landscape and regional biodiversity of resources (DivGUD) JF - Ecology letters N2 - 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. KW - biodiversity KW - cascading effects KW - foraging behaviour KW - functional traits KW - giving-up density KW - landscape of fear KW - optimal foraging KW - patch use Y1 - 2022 U6 - https://doi.org/10.1111/ele.13901 SN - 1461-0248 VL - 25 IS - 1 SP - 3 EP - 16 PB - Wiley-Blackwell CY - Oxford [u.a.] ER - TY - JOUR A1 - Dammhahn, Melanie A1 - Lange, Pauline A1 - Eccard, Jana T1 - The landscape of fear has individual layers BT - an experimental test of among-individual differences in perceived predation risk during foraging JF - Oikos N2 - Perceived predation risk varies in space and time creating a landscape of fear. This key feature of an animal's environment is classically studied as a species-specific property. However, individuals differ in how they solve the tradeoff between safety and reward and may, hence, differ consistently and predictively in perceived predation risk across landscapes. To test this hypothesis, we quantified among-individual differences in boldness and activity and exposed behaviourally phenotyped male bank voles Myodes glareolus individually to two different experimental landscapes of risks in large outdoor enclosures and provided resources as discrete food patches. We manipulated perceived predation risk via vegetation height between 2 and > 30 cm and quantified patch use indirectly via RFID-logging and giving-up densities. We statistically disentangled among-individual differences in microhabitat use from spatially varying perceived risk, i.e. landscape of fear. We found that individuals varied in mean vegetation height of their foraging microhabitats and that this microhabitat selection matched the intrinsic individual differences in perceived risk. As predicted by the patch use model, all individual's perceived higher risks when foraging in lower vegetation. However, individuals differed in their reaction norm slopes of perceived risk to vegetation height, and these differences in slopes were consistent across two different landscapes of risks and resources. We interpret these results as evidence for individual landscapes of fear, which could be predicted by among-individual differences in activity and boldness. Since perceived predation risk affects when and where to forage, among-individual differences in fear responses could act as a mode of intraspecific niche complementarity (i.e. individual niche specialization), help explain behavioural type by environment correlations, and will likely have cascading indirect effects on lower trophic levels. KW - activity KW - behavioural reaction norm KW - giving-up density KW - patch use; KW - optimal foraging KW - personality KW - risk allocation KW - rodents Y1 - 2022 U6 - https://doi.org/10.1111/oik.09124 SN - 0030-1299 SN - 1600-0706 VL - 2022 IS - 6 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Eccard, Jana A1 - Liesenjohann, Thilo A1 - Dammhahn, Melanie T1 - Among-individual differences in foraging modulate resource exploitation under perceived predation risk JF - Oecologia N2 - 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. KW - animal personality KW - giving-up density KW - intra-specific trait variation KW - landscape of fear KW - optimal foraging KW - predation risk KW - resource KW - exploitation Y1 - 2020 U6 - https://doi.org/10.1007/s00442-020-04773-y SN - 0029-8549 SN - 1432-1939 VL - 194 IS - 4 SP - 621 EP - 634 PB - Springer CY - Berlin ER -