Drs. Ellen Blomme
Terrestrial Ecology Unit
Department of Biology
Ghent University
K.L. Ledeganckstraat 35
9000 Gent Belgium
E-mail: Ellen.Blomme@UGent.be
Linking pathology with ecology to preserve commonness of a declining emblematic species, the common toad (Bufo bufo)
The European common toad (Bufo bufo) occupies a variety of habitats. They are an important source of energy transfer between ponds and their surrounding terrestrial habitats. Common and widespread species, like the common toad, can make up a significant part of the biomass. However, amphibians are a main victim in this current sixth mass extinction mainly driven by anthropogenic influences. In this current extinction event also common and more widespread species are threatened. Small proportional reductions in populations of common species already have a large impact on ecosystem functioning and biomass. Therefore, preserving “commonness” is increasingly considered key in conservation science.
Understanding the causes of toad decline is key in designing measures to avert further biodiversity loss. Such enigmatic declines are probably driven by a complex interplay between multiple stressors: land use (e.g., agricultural cultivation practices, pesticide use), habitat (e.g., loss of ponds and small landscape elements) and connectivity loss (including migratory connectivity between breeding ponds and adult terrestrial habitats), climate change, loss of genetic diversity and diseases. To initiate the investigation into the causes behind toad declines, it is necessary to conduct a comprehensive analysis of the population trends in relation to landscape attributes.
In this project, we will collect a large field-data set to gain detailed insight in the putative causes of decline. For this we will compare declining with healthy populations so that we can identify life stages and life history traits that are negatively affected in the declining populations. This will point out the critical points of fitness loss. We will also look into health indicators and potential drivers of decline.
My phd will focus on:
- quantifying the decline in the toad populations in Flanders and their spatial characteristics. This will provide comprehensive data regarding the geographic extent, the magnitude of the problem and the identification of populations for further studies.
- The analysis of the field-data set comprising of the age, stress, prey diversity and abundance.
- The age of reproducing animals reflect the population’s demography and survival. The age of adult toads can be inferred from growth rings in bone tissue (skeletochronography).
- The stress of the animals can be quantified by looking at the telomeres (in relation to the age of the individuals. Shorter telomere mean more stress. Mouth swabs will be used to collect the DNA of the toads. Afterwards the samples are processed in the lab.
- For the prey diversity and abundance, the diet of the toads will be compared using fecal metabarcoding. Further, the invertebrate biomass will be used as proxy for food availability. This will be determined using quadrat sampling and Berlese extraction.