Title: Plant phenological events as an indicator for the beginning of the migration of three Central European amphibian species
Amphibians are among the most endangered vertebrates. One of the reasons for population decline is habitat fragmentation through land use and roads, which limits the seasonal migration of amphibians between their habitats. Amphibian migrations in spring are influenced by meteorological factors such as temperature, and the same applies in a similar way to plant phenology. As climatic conditions vary between years, phenological events such as amphibian migration take place at different times.
The aim of this thesis was to find a possible association between the phenological phases of selected plant species and the beginning of amphibian migration, since possible associations would allow a prediction of amphibian migration by phenological events. In this master thesis amphibian migration and phenological plant phases are compared based on data recorded in Austria between 2008 and 2018. Three amphibian species (Bufo bufo, Rana temporaria, R. dalmatina), five tree species (Aesculus hippocastanum, Betula pendula, Larix decidua, Prunus armeniaca, Salix caprea), one shrub species (Corylus avellana) and one herb (Galanthus nivalis) were studied. A dataset of amphibian sightings was used, which originates from the herpetofaunistic database of the Natural History Museum Vienna and from the two Citizen Science projects naturbeobachtung.at (Austrian Society for Nature Conservation) and Project Roadkill; plant phenological data were obtained from the Citizen Science database PhenoWatch. The data sets were compared and analysed using linear regression modelling.
The results showed strong similarities between the phenology of some plant species (Larix decidua, Salix caprea, Prunus armeniaca) and the beginning of the migration of Rana temporaria. The flowers of Prunus armeniaca and Salix caprea were particularly suitable as indicators of the beginning of the migration of amphibians. These results could provide a simple way for people implementing amphibian conservation measures to make local predictions about the beginning of amphibian migration.
For example, a person has noticed the bloom of the willow in his garden or on his way to work on 2 March and now wants to predict the amphibian migration of the grass frog. With the help of a decision tree and the graphical representation of the models, the person could find out graphically or with a simple calculation that the amphibian migration according to the model is estimated about 20 days later, on 22 March. Prediction through the flowering of the apricot is even easier - the results show that the migration of the grass frog takes place around the same time, usually a few days later.