Population connectivity of native and invasive species in the Fens: what are appropriate habitats for conservation?

Lead Research Organisation: University of Aberdeen
Department Name: Inst of Biological and Environmental Sci

Abstract

This fully-funded project provides the opportunity for a motivated student to learn cutting-edge skills in conservation science and to make an important contribution to the conservation and restoration of the UK's largest wetland. The student will: 1) gain skills in population genetics and individually-based modelling, 2) deliver internationally relevant science related to resolving trade-offs between improving habitat connectivity for native species while minimising the spread of invasive species, and 3) work closely with ecologists and practitioners in the conservation organisation Natural England, to deliver effective strategies for restoration of the Fens in eastern England. The Fens is an ecologically important area, covering 3900 km2 and providing critical habitat for >13,000 species (1500 of which are of conservation concern and 50 of which are Fens endemics). However, due to intensive land use, less than 1% of this habitat remains intact. Efforts are currently underway to restore connectivity among remaining habitat fragments, to conserve the biodiversity of this valuable ecosystem. However, the Fens are also home to a number of invasive species, and improving connectivity among habitat patches may have the unwanted consequence of hastening the spread of these species. This project will have a direct applied relevance to conservation decisions for the Fens, and will also address broader, global issues relating to the challenge of improving native species connectivity in the context of invaded ecosystems. For this project, the student will conduct fieldwork and genetic analyses to assess connectivity for a range of native and invasive species that specialise on wetland habitats, and which have a local stronghold in the Fens. The student will also use a suite of new modelling approaches to predict the consequences of various conservation strategies, with an opportunity to contribute to the ongoing development of the increasingly popular software tool RangeShifter for understanding eco-evolutionary dynamics and the consequences of land management and conservation strategies.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
NE/P009697/1 01/10/2017 31/12/2021
1966071 Studentship NE/P009697/1 01/10/2017 31/12/2021 Calum Anderson
NE/W502820/1 01/04/2021 31/03/2022
1966071 Studentship NE/W502820/1 01/10/2017 31/12/2021 Calum Anderson
 
Description The Fens is overlaid with an expansive and dense "wet-web" of drainage channels and ditches that might facilitate and influence patterns of species dispersal across the landscape for animals that can swim through its channels to get from one place to another. On many intensive agricultural landscapes such as the Fens long-linear landscape elements (LLEs), such as ditches, hedgerows or grassy field margins, have been known to influence patterns of animal dispersal and connectivity as LLEs can provide narrow corridors of sheltered terrain through which small animals might more safely travel across through stretches of exposed territory (such as fields or urban elements).
It has thus been suggested among conservationists that by increasing the number and density of LLEs on a landscape it should be possible to improve the ability of animals to move around and thereby access more of the landscape's resources (such as remote patches of habitat).
However, our investigations using an individual-based model (RangeShifter v.2) to predict how individual animals might move between habitat patches through experimentally altered networks of LLEs found that the addition of new LLEs could sometimes be detrimental to connectivity depending on their orientation to the habitat patches.
Our model predicted that the addition of new LLEs only promoted connectivity between two areas if they were oriented running toward both locations, parallel to the straightest path between them. If new LLEs ran at a perpendicular angle to the straightest path between habitat patches, not only did they not always promote connectivity but in some cases would inhibit it. Additional LLEs could have this effect by increasing the complexity of the network structure and thereby reduce the likelihood of an individual navigating their way successfully out of it, like an individual trying to find the way out of a complex maze.
These results suggest that efforts to improve a landscape's connectivity using LLEs should take into careful consideration the orientation of new ditches/hedgerows to neighbouring resource patches such as optimal breeding or feeding habitats. If insufficient attention is paid to the orientation of new LLEs then the increased freedom of movement they might offer for dispersing animals may grant them as many or more opportunities to accidentally miss landscape resources as to successfully find them.
Exploitation Route Conservationists investigating the use of improving or creating new ditches or hedgerows to improve connectivity might use the above results as potential evidence for the important role that the orientation of LLEs plays in animal dispersal.

The results not only suggest that improvement should be targeted toward LLEs that lie closest to the straightest paths between resource patches relevant to the species in question, but that improving additional/superfluous LLEs might harm connectivity by creating options for animal movement that do not facilitate their direct travel from location to the other. Similarly, if new LLEs are to be created to facilitate dispersal between two locations they may be most beneficial and least detrimental if they are erected as closely as possible along the straightest direct path between said locations.
Sectors Agriculture, Food and Drink,Environment