08 Nov Jamie-Lee Hunt
Jamie-Lee is an recent University of Western Australia graduate from Southwest Western Australia with a background in both anthropology and conservation biology. Jamie-Lee’s research thesis investigated the role of spiders in riparian food webs in sites of varying riparian condition. She has a strong interest in riparian ecology, as well as the effect of human agency on the health and resilience of riparian ecosystems.
Ecosystem Resilience And The Effects Of Degradation On Riparian Spider Community Structure And Carbon Flux Across The Aquatic-terrestrial Interface.
Riparian zones contribute to broader landscape resilience by assimilating, transforming and transferring carbon between aquatic and terrestrial biomes, however riparian ecosystems are currently subject to extensive degradation through clearing, grazing, and fragmentation. These disturbances are known to alter biodiversity thus interfering with broader ecosystem function by changing the dynamics of carbon fluxes. Riparian spiders are influential in structuring food webs, contributing to broader ecosystem resilience by assimilating nutrient rich aquatic carbon into terrestrial food webs through the predation of emergent aquatic invertebrates. This study aimed to document spider assemblages for 5 streams on the south coast of Western Australia, to determine if their role in ecosystem processes are altered by riparian degradation. We used transect surveys along a gradient of riparian degradation to explore changes in spider assemblages. We used stable isotope analysis of carbon and nitrogen to investigate any changes in spider diets associated with riparian habitat degradation. Whilst spider diversity and abundance were not directly affected by riparian degradation, there was some evidence that understory density, canopy cover, water temperature and salinity influenced the abundance of orb weaving spiders and cursorial hunting spiders. Riparian disturbance was found to reduce the contribution of aquatic carbon to diets of riparian spiders from approximately 45% at intact stream sites to as low as 17% in degraded riparian habitats. These findings provide evidence of the flow-on effects of changes to biodiversity on ecosystem function in riparian areas. These results emphasise the significance of biological and structural diversity during river restoration projects and have important implications for management decisions related to optimising ecosystem function and enhancing resilience in stream riparian zones.