Modelling of climatic tolerances of three earthworm species; Satchellius mammalis, Lumbricus friendi and Lumbricus festivus using Maximum Entropy Modeling

Abstract

Earthworm distributions are poorly known and individual species climatic tolerances, even less so. This paper sets out to use three species with a mainly Anglo-French distribution to test out whether using Maximum Entropy Modelling (Maxent) could be useful when studying earthworm distributions. It also gives an indication of how the likely climatic changes over a 50 year period will affect them. Overall the software seems to give useful information of where across Europe a particular species will thrive, even if not currently recorded there. It gives a real insight into how particular species might be better able to survive longer drier periods than others and which are on the edge of their climatic range already. Maxent modelling was clearly successful in demonstrating that the distributions of the ecologically different earthworm species are affected by a combination of different environmental variables. In the case of the epigeic Satchellius mammalis they are the annual temperature range, the precipitation of the driest month and the mean annual precipitation, for the epi-endogeic Lumbricus festivus they are the precipitation of the driest month, the precipitation of the wettest month and the annual temperature range. For the anecic Lumbricus friendi the most important environmental variables proved to be the annual temperature range, the mean diurnal temperature range and the precipitation seasonality.