Browsing by Subject "Madagascar"

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    Season and reproductive activity influence cortisol levels in the Malagasy primate Lepilemur edwardsi
    (2022) Bethge, Janina; Fietz, Joanna; Razafimampiandra, Jean Claude; Ruthsatz, Katharina; Dausmann, Kathrin H.
    Throughout the year, wild animals are exposed to a variety of challenges such as changing environmental conditions and reproductive activity. These challenges may affect their stress hormone levels for varying durations and in varying intensities and impacts. Measurements of the glucocorticoid hormone cortisol in the hair of mammals are considered a good biomarker for measuring physiological stress and are increasingly used to evaluate stress hormone levels of wild animals. Here, we examined the influence of season, reproductive activity, sex, as well as body condition on hair cortisol concentrations (HCC) in Lepilemur edwardsi, a small Malagasy primate species. L. edwardsi lives in the seasonal dry forests of western Madagascar, which are characterized by a strongly changing resource availability throughout the year. We hypothesized that these seasonal changes of resource availability and additionally the reproductive cycle of this species would influence HCC of L. edwardsi. Results revealed that hair cortisol concentration of females did not change seasonally or with the reproductive cycle. However, we found a significant increase of hair cortisol levels in males from the early wet season during the early dry season (mating season). This increase is presumably due to changed behavior during the mating season, as sportive lemurs travel more and show aggressive behavior during this time of the year. This behavior is energy‐costly and stressful, and presumably leads to elevated HCC. As elevated cortisol levels may impair immune function, L. edwardsi males might also be more susceptible to parasites and diseases, which is unfavorable in particular during a period of low resource availability (dry season).
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    Win-win opportunities combining high yields with high multi-taxa biodiversity in tropical agroforestry
    (2022) Wurz, Annemarie; Tscharntke, Teja; Martin, Dominic Andreas; Osen, Kristina; Rakotomalala, Anjaharinony A. N. A.; Raveloaritiana, Estelle; Andrianisaina, Fanilo; Dröge, Saskia; Fulgence, Thio Rosin; Soazafy, Marie Rolande; Andriafanomezantsoa, Rouvah; Andrianarimisa, Aristide; Babarezoto, Fenohaja Soavita; Barkmann, Jan; Hänke, Hendrik; Hölscher, Dirk; Kreft, Holger; Rakouth, Bakolimalala; Guerrero-Ramírez, Nathaly R.; Ranarijaona, Hery Lisy Tiana; Randriamanantena, Romual; Ratsoavina, Fanomezana Mihaja; Raveloson Ravaomanarivo, Lala Harivelo; Grass, Ingo; Wurz, Annemarie; Conservation Ecology, Department of Biology, Philipps-University Marburg, Marburg, Germany; Tscharntke, Teja; Centre for Biodiversity and Sustainable Land Use (CBL), University of Göttingen, Göttingen, Germany; Martin, Dominic Andreas; Department of Geography, University of Zurich, Zürich, Switzerland; Osen, Kristina; Tropical Silviculture and Forest Ecology, University of Göttingen, Göttingen, Germany; Rakotomalala, Anjaharinony A. N. A.; Entomology Department Faculty of Science, University of Antananarivo, Antananarivo, Madagascar; Raveloaritiana, Estelle; Plant Biology and Ecology Department, University of Antananarivo, University of Antananarivo, Antananarivo, Madagascar; Andrianisaina, Fanilo; Department of Tropical Agriculture and Sustainable Development, Higher School of Agronomic Science,University of Antananarivo, Antananarivo, Madagascar; Dröge, Saskia; Division of Forest, Nature and Landscape, KU Leuven, Leuven, Belgium; Fulgence, Thio Rosin; Natural and Environmental Sciences, Regional University Centre of the SAVA Region (CURSA), Antalaha, Madagascar; Soazafy, Marie Rolande; Doctoral School of Natural Ecosystems (EDEN), University of Mahajanga, Mahajanga, Madagascar; Andriafanomezantsoa, Rouvah; Zoology and Animal Biodiversity, Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar; Andrianarimisa, Aristide; Zoology and Animal Biodiversity, Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar; Babarezoto, Fenohaja Soavita; Diversity Turn in Land Use Science, coordination office, Sambava, Madagascar; Barkmann, Jan; Department of Agricultural Economics and Rural Development, Research Unit Environmental- and Resource Economics, University of Göttingen, Göttingen, Germany; Hänke, Hendrik; Department of Agricultural Economics and Rural Development, Research Unit Environmental- and Resource Economics, University of Göttingen, Göttingen, Germany; Hölscher, Dirk; Tropical Silviculture and Forest Ecology, University of Göttingen, Göttingen, Germany; Kreft, Holger; Biodiversity, Macroecology and Biogeography, University of Göttingen, Göttingen, Germany; Rakouth, Bakolimalala; Plant Biology and Ecology Department, University of Antananarivo, University of Antananarivo, Antananarivo, Madagascar; Guerrero-Ramírez, Nathaly R.; Biodiversity, Macroecology and Biogeography, University of Göttingen, Göttingen, Germany; Ranarijaona, Hery Lisy Tiana; Doctoral School of Natural Ecosystems (EDEN), University of Mahajanga, Mahajanga, Madagascar; Randriamanantena, Romual; Natural and Environmental Sciences, Regional University Centre of the SAVA Region (CURSA), Antalaha, Madagascar; Ratsoavina, Fanomezana Mihaja; Zoology and Animal Biodiversity, Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar; Raveloson Ravaomanarivo, Lala Harivelo; Entomology Department Faculty of Science, University of Antananarivo, Antananarivo, Madagascar; Grass, Ingo; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany
    Resolving ecological-economic trade-offs between biodiversity and yields is a key challenge when addressing the biodiversity crisis in tropical agricultural landscapes. Here, we focused on the relation between seven different taxa (trees, herbaceous plants, birds, amphibians, reptiles, butterflies, and ants) and yields in vanilla agroforests in Madagascar. Agroforests established in forests supported overall 23% fewer species and 47% fewer endemic species than old-growth forests, and 14% fewer endemic species than forest fragments. In contrast, agroforests established on fallows had overall 12% more species and 38% more endemic species than fallows. While yields increased with vanilla vine density and length, non-yield related variables largely determined biodiversity. Nonetheless, trade-offs existed between yields and butterflies as well as reptiles. Vanilla yields were generally unrelated to richness of trees, herbaceous plants, birds, amphibians, reptiles, and ants, opening up possibilities for conservation outside of protected areas and restoring degraded land to benefit farmers and biodiversity alike.