title: Forests of opportunities and mischief: disentangling the interactions between forests, parasites and immune responses.
abstract: Habitat characteristics determine the presence of individuals through resource availability, but at the same time, such features also influence the occurrence of parasites. We analyzed how birds respond to changes in interior forest structures, to forest management regimes, and to the risk of haemosporidian infections. We captured and took blood samples from blackcaps (Sylvia atricapilla) and chaffinches (Fringilla coelebs) in three different forest types (beech, mixed deciduous, spruce). We measured birds' body asymmetries, detected avian haemosporidians, and counted white blood cells as an immune measure of each individual per forest type. We used, to our knowledge for the first time, continuous forest structural parameters to quantify habitat structure, and found significant effects of habitat structure on parasite prevalence that previously have been undetected. We found three times higher prevalence for blackcaps compared with chaffinches. Parasite intensity varied significantly within host species depending on forest type, being lowest in beech forests for both host species. Structurally complex habitats with a high degree of entropy had a positive effect on the likelihood of acquiring an infection, but the effect on prevalence was negative for forest sections with a south facing aspect. For blackcaps, forest gaps also had a positive effect on prevalence, but canopy height had a negative one. Our results suggest that forest types and variations in forest structure influence the likelihood of acquiring an infection, which subsequently has an influence on host health status and body condition; however, responses to some environmental factors are host-specific.
authors.affiliation: Institute of Zoology, University of Natural Resources and Life Sciences, Vienna, Austria; Smithsonian Conservation Biology Center, National Zoological Park, 1500 Remount Road, Front Royal, VA 22630, USA. Electronic address: swen.renner@boku.ac.at.
authors.forename: Swen C
authors.initials: SC
authors.lastname: Renner
authors.affiliation: Institute of Experimental Ecology, University of Ulm, Ulm, Germany.
authors.forename: Bruntje
authors.initials: B
authors.lastname: Lüdtke
authors.affiliation: Max-Planck-Institute for Biogeochemistry, Jena, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Kaiser
authors.affiliation: Institute of Experimental Ecology, University of Ulm, Ulm, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Kienle
authors.affiliation: Institute of Biology I (Zoology), University of Freiburg, Freiburg, Germany.
authors.forename: H Martin
authors.initials: HM
authors.lastname: Schaefer
authors.affiliation: Department of Wildlife Ecology and Management, University of Freiburg, Freiburg, Germany.
authors.forename: Gernot
authors.initials: G
authors.lastname: Segelbacher
authors.affiliation: Institute of Experimental Ecology, University of Ulm, Ulm, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Tschapka
authors.affiliation: Red de Biología y Conservación de Vertebrados, Instituto de Ecología, A.C. Xalapa, Veracruz, Mexico.
authors.forename: Diego
authors.initials: D
authors.lastname: Santiago-Alarcon
mesh_terms: D000818:Animals; D044822:Biodiversity; D004247:DNA; D017753:Ecosystem; D065928:Forests; D005858:Germany / Q000453:epidemiology; D016787:Haemosporida / Q000276:immunology / Q000502:physiology*; D006790:Host-Parasite Interactions; D046109:Passeriformes / Q000097:blood / Q000276:immunology* / Q000469:parasitology*; D015995:Prevalence; D011529:Protozoan Infections, Animal / Q000097:blood / Q000453:epidemiology / Q000276:immunology; D014197:Trees / Q000276:immunology* / Q000469:parasitology*
chemical_list: D004247:DNA
keywords: Ecosystem process; Forest structure; Haemosporidia; Host-parasite interaction; Landscape epidemiology; LiDAR; Malaria parasites; Structural equations modeling