An appraisal of the Oryctolagus cuniculus population on the island of Comino and its relationship to the vegetation

Abstract

The European rabbit Oryctolagus cuniculus (Linnaeus, 1758) is the only wild mammal herbivore of the Maltese archipelago, originating from the Iberian Peninsula and classified today as endangered on the IUCN Red List. Its grazing is suspected to be a major factor in the degradation of some Annex I habitats on the island of Comino by its latest Natura 2000 management plan. Given large identified knowledge gaps around its local ecology, related scientific methods and management objectives, this exploratory research evaluated standard methodologies for the monitoring of Oryctolagus cuniculus population abundance and its potential impacts on vegetation cover, species richness and above-ground biomass. A systematic quadrat survey was employed for the joint observation of European rabbit dung pellets, vegetation canopy-cover and species richness across three sites, concurrently with a stratified purposeful block experiment to identify the regeneration potential of selected plant species in grazed and non-grazed plots. The quadrat survey was adapted to relative density monitoring but not to the observed vegetation parameters, while crucial parameters were lacking for absolute density estimation. Opposite trends were observed in the vegetation in the absence of grazing, suggesting a partial adaptation of the Comino garrigue to European rabbit grazing. A number of potential areas of further research are proposed along with methodological insights.