TY  - THES
A1  - Hantzschmann, Alena Marcella
T1  - Population ecology of the yellow-bellied toad (Bombina variegata) at the northern range margin: Focusing on demography and genetics
N2  - Amphibian populations are declining worldwide for multiple reasons such as habitat destruction and climate change. An example for an endangered European amphibian is the yellow-bellied toad Bombina variegata. Populations have been declining for decades, particularly at the northern and western range margin. One of the extant northern range centres is the Westerwald region in Rhineland-Palatinate, Germany. To implement informed conservation activities on this threatened species, knowledge of its life-history strategy is crucial. This study therefore focused on different developmental stages to test predictions of life-history theory. It addressed (1) developmental, (2) demographic and (3) genetic issues of Bombina variegata as a model organism: (1) Carry-over effects from larval environment to terrestrial stages and associated vulnerability to predators were investigated using mesocosm approaches, fitness tests and predation trials. (2) The dynamics and demography of B. variegata populations were studied applying a capture-mark-recapture analysis and skeletochronology. The study was complemented through (3) an analysis of genetic diversity and structuring of B. variegata populations using 10 microsatellite loci. In order to reveal general patterns and characteristics among B. variegata populations, the study focused on three geographical scales: local (i.e. a former military training area), regional (i.e. the Westerwald region) and continental scale (i.e. the geographical range of B. variegata). The study revealed carry-over effects of larval environment on metamorph phenotype and behaviour causing variation in fitness in the early terrestrial stage of B. variegata. Metamorph size and condition are crucial factors for survival, as small-sized individuals were particularly prone to predator attacks. Yellow-bellied toads show a remarkable fast-slow continuum of the life-history trait longevity. A populations’ position within this continuum may be determined by local environmental stochasticity, i.e. an extrinsic source of variation, and the efficiency of chemical antipredator protection, i.e. an intrinsic source of variation. Extreme longevity seems to be an exception in B. variegata. Senescence was absent in this study. Weather variability affected reproductive success and thus population dynamics. The dispersal potential was low and short-term fragmentation of populations caused significant genetic differentiation at the local scale. Long-term isolation resulted in increased genetic distance at the regional scale. At the continental scale, populations inhabiting the marginal regions were deeply structured with reduced allelic richness. As consequence of environmental changes, short-lived and isolated B. variegata populations at the range margin may face an increased risk of extinction. Conservation measures should thus improve the connectivity among local populations and reinforce annual reproductive success. Further research on the intraspecific variation in B. variegata skin toxins is required to reveal potential effects on palatability and thus longevity.
KW  - Yellow-bellied toad
KW  - Bombina variegata
KW  - Demography
KW  - Genetics
KW  - Rhineland-Palatinate
KW  - Conservation
KW  - Habitat Fragmentation
KW  - Carry-over effects
KW  - Longevity
KW  - Life history
KW  - Fast-slow continuum
KW  - Climate
KW  - Gelbbauchunke
KW  - Demographie
KW  - Genetik
KW  - Rheinland-Pfalz
KW  - Naturschutzmanagement
KW  - Habitatfragmentierung
KW  - Langlebigkeit
KW  - Klima
KW  - Gelbbauchunke
Y1  - 2020
UR  - https://kola.opus.hbz-nrw.de/frontdoor/index/index/docId/2073
UR  - https://nbn-resolving.org/urn:nbn:de:kola-20737
N1  - Ohne die enthaltenen Zeitschriftenaufsätze.
ER  -