Effects of experimental disturbance on multi-taxa assemblages and traits: conservation implication in a forest-open landscape mosaic

Pedley, Scott M. (2012) Effects of experimental disturbance on multi-taxa assemblages and traits: conservation implication in a forest-open landscape mosaic. Doctoral thesis, University of East Anglia.

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Overcoming fragmentation and isolation requires innovative solutions if cohesive biodiversity networks are to be created in modernised landscapes. Within Europe much of the biodiversity interest is in semi-natural habitats that exist as isolated reserves. This thesis aimed to test the connectivity potential of open habitat for lowland heathland biodiversity within a mosaic forest landscape. A range of experimental management treatments were implemented covering a gradient of disturbance intensity intended to enhance connectivity through plantation forest for early-successional biodiversity. Both species composition and life history traits were investigated enabling a comprehensive interpretation of response across multiple species. Sampling programs identified over 87000 invertebrates, comprising 38188 spiders from 183 species, 41531 ants from 20 species and 7564 carabids from 93 species, and recorded 23241 observations of 222 vascular plant species. Initial investigations revealed forestry trackways contained a component of the regional heathland spider assemblage, but this was significantly degraded as adjacent forest matured. Experiments to augment heathland biodiversity in trackways resulted in contrasting responses between taxa. Specialist carabids and vascular plants (associated with heathland or early-successional habitats), increased in abundance and richness with high intensity disturbance. Spider assemblages were left depauperate and did not completely recover after two seasons; ants did not respond at any disturbance level. Trait-based analysis showed that the abundance of aerial dispersers increased and size decreased with disturbance intensity for carabids and plants. In contrast, spider body size increased with greater disturbance and aerial dispersal was not significant. For spiders, ephemeral stepping stones, in the form young restock coupes, support the majority of the heath assemblage, whereas open linear habitat in the form of trackways, suffer from edge effects and are dominated by generalist and woodland spiders. Network cohesion will benefit from intensive disturbance management and a combination of connectivity elements to incorporate contrasting dispersal abilities.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Environmental Sciences
Depositing User: Users 2593 not found.
Date Deposited: 24 Jan 2014 11:24
Last Modified: 24 Jan 2014 11:24
URI: https://ueaeprints.uea.ac.uk/id/eprint/47390


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