Kompetenzzentrum für Biodiversität und integrative Taxonomie (KomBioTa)

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Browsing Kompetenzzentrum für Biodiversität und integrative Taxonomie (KomBioTa) by Person "Erhardt, Stefanie"

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    Habitat requirements and home range use of the threatened garden dormouse (Eliomys quercinus) in a coniferous forest
    (2025) Erhardt, Stefanie; Pfister, Jan; Beier, Marieke; Vorderbrügge, Rieke; Förschler, Marc I.; Fietz, Joanna; Erhardt, Stefanie; Department of Zoology, Institute of Biology, University of Hohenheim, Stuttgart, Germany; Pfister, Jan; Department of Zoology, Institute of Biology, University of Hohenheim, Stuttgart, Germany; Beier, Marieke; Department of Zoology, Institute of Biology, University of Hohenheim, Stuttgart, Germany; Vorderbrügge, Rieke; Department of Zoology, Institute of Biology, University of Hohenheim, Stuttgart, Germany; Förschler, Marc I.; Black Forest National Park, Department for Ecological Monitoring, Research and Species Protection, Seebach, Germany; Fietz, Joanna; Department of Zoology, Institute of Biology, University of Hohenheim, Stuttgart, Germany
    Understanding habitat use and requirements is essential for the conservation of endangered species, such as the garden dormouse (Eliomys quercinus). Therefore, we radio-tracked garden dormice (n = 39) in the Black Forest National Park (Germany) between 2019 and 2021, determined home range size by calculating autocorrelated kernel density estimates, located resting sites during the day, and analyzed their resting behavior. Furthermore, we investigated their crossing behavior across paths varying in width, in the degree of canopy closure, and understory. Median home range size was 3.8 ha (Q25 = 2.3 ha, Q75 = 6.6 ha) in adults and 1.9 ha in juveniles. Adult males increased their home range sizes during reproduction. In September, shortly before hibernation, adults used smaller home ranges, likely to save energy. During the day, garden dormice used nest boxes and natural nests under the ground as resting sites. Ground holes were an important resource as they were most frequently used by reproductive individuals and also at low ambient temperatures (0.1–14.7 °C). In contrast, nest boxes were used only at higher ambient temperatures (> 5.9 °C). Forest trails with tree cover and/or undergrowth were frequently crossed by adults, while 4 m wide forest paths without tree cover or undergrowth were rarely crossed. The results of our study show that the preservation of natural resting sites, the restoration of forest trails, or the installation of crossing structures are important conservation measures for the garden dormouse, facilitating migration and colonization of new habitats and reducing the risk to lose genetic variability.
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    Reduced body mass in a highly insectivorous mammal, the garden dormouse — ecological consequences of insect decline?
    (2025) Erhardt, Stefanie; Förschler, Marc I.; Fietz, Joanna; Erhardt, Stefanie; Department of Zoology, Institute of Biology, University of Hohenheim, Stuttgart, Germany; Förschler, Marc I.; Department for Ecological Monitoring, Research and Species Protection, Black Forest National Park, Seebach, Germany; Fietz, Joanna; Department of Zoology, Institute of Biology, University of Hohenheim, Stuttgart, Germany
    Biodiversity is decreasing worldwide, and early indicators are needed to identify endangered populations before they start to decline in abundance. In mammals, body mass (BM) is regarded as an indicator of fitness, and its loss is used as an early warning signal preceding population decline. The garden dormouse ( Eliomys quercinus , Gliridae, BM: 60–110 g) is a small mammalian hibernator that has disappeared from over 50% of its former range in the last decades. The aim of this study was to investigate whether garden dormice from a presumably thriving and stable population already show early warning signals, which may precede a population decline. We therefore conducted capture‐mark‐recapture studies during 2003–2005 (Period 1) and 2018–2021 (Period 2) in the Northern Black Forest, one of its last natural distribution areas in Germany. We collected fecal samples, measured BM, and tibia length as a proxy for size and age. Results revealed that in Period 2 adult dormice had a significantly lower (12%) pre‐hibernation BM, corrected for body size, and juveniles showed a significantly lower BM gain after weaning than nearly two decades ago. Fecal samples collected in Period 2 showed that arthropods represented the main food residues in fecal samples during juvenile growth and pre‐hibernation fattening. Ambient temperature during hibernation showed no correlation with BM at emergence. We could not detect a phenological time shift in reproduction; however, we found only one birth peak in Period 2, compared with two birth peaks in Period 1. Observed changes in BM and reproduction pattern represent early warning signals, as they point to an insufficient availability of high‐quality food, which prevents dormice from meeting their nutritional requirements, with potentially serious consequences for their reproductive success and survival. As arthropods are the dominant food resource, their decline may at least partly explain this phenomenon.