Jersey multi-species distribution, habitat suitability and connectivity modelling

From Natural Environment, Growth, Housing and Environment, States of Jersey

Populations of some of Jersey’s rarest plants and animals survive in isolated pockets across the Island, often in places which remain unprotected, and are, therefore, at threat from the growing anthropological impacts on habitats across the land surface.

The Natural Environment, Growth, Housing and Environment, States of Jersey (formerly Department of the Environment) commissioned the Amphibian and Reptile Conservation Trust (ARC) to determine priority areas for protected species and habitats, and connecting routes between them, in order to aid spatial planning and future protected area designation. The outcomes are based on cost / benefit analysis, providing best economic and conservation value. The report’s authors, Rob Ward and John Wilkinson are frequent visitors to Jersey and well known to Birds On The Edge supporters.

Whilst individual species have previously been assessed on their conservation requirements in Jersey, this is the first time that multiple species (17) have been assessed in the same project.

This study expands on previous efforts by incorporating a wide range of species of varying taxa, ecological roles, traits and conservation status in order to inform an Island-wide plan for maintaining, improving and designating wildlife areas. It highlights areas where improvements to connectivity are most beneficial, and how these may be tied in with other efforts in parallel for maximum return on investment.

In this report, spatial modelling approaches are used to carry out the following tasks:

  • predict and map the distribution on 17 selected species including toad, grass snake, Jersey bank vole, red squirrel, common pipistrelle, field cricket, lizard orchid and ragged robin
  • identify the areas of highest habitat suitability for the 17 species, and evaluate how those areas are currently protected
  • assess which factors, e.g. habitat type, influence the species’ distributions
  • separately assess species associated with urban environments so conservation priorities can be identified for both urban and non-urban environments
  • map the most likely wildlife corridors
  • identify landscape priorities for protection based on their value to wildlife connectivity and current protected status.

The (17) focal species or species groups (genera) selected for species distribution modelling were among Jersey’s protected species and assessed in view of dispersal and movement capabilities. Plants were dominated by orchid species (class Liliopsida) which appear to be better recorded than other flora; perhaps due to their charismatic and overt appearance and specific habitats making them easier to locate and be of greater popularity. Although several invertebrate species were recommended for this study, only the field cricket (Gryllus campestris) had sufficient records. Those species that could not be included at this stage are evaluated later on through other approaches. Long-eared bat roosts (Plecotus spp.) and waxcap fungi (Hygrocybe spp.) were modelled at the genus level as intra-genus members were considered to have similar habitat associations.

Birds were excluded due to a lack of data on nesting sites and their ability to traverse across the Island with ease. However, their needs are accounted for in the report.

The protected species reviewed were highly variable in their movement and dispersal abilities. Given these findings and the overall aim of producing a well-connected network for a wide variety of species, the report authors used a precautionary approach that would allow movement of dispersal-limited species, but that also contained patches with sufficient size to support the most wide-ranging species. Although referring to individual distances and ranges in the review, the area encompassed by a functioning population is considerably larger than that of an individual. Therefore, to provide areas that are suitable for not only individuals, but also entire populations to move through and inhabit, Jersey must ensure those areas are of a sufficient magnitude.

This work supports the decision making processes within Growth, Housing and Environment, States of Jersey, with implications for wildlife conservation, planning and building.

Download the report Jersey multi-species distribution, habitat suitability & connectivity modelling, executive summary and appendices

One thought on “Jersey multi-species distribution, habitat suitability and connectivity modelling

  1. Too many humans is the problem, not to mention the highly subsidised chemical potato industry. Best thing we ever did was leave 2 years ago

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