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Ryan Burrows

BurrowsRcropMr Ryan Burrows

PhD student

Topic: Biogeochemical cycling and ecosystem processes in small headwater streams - assessing the effects of forest management

University of Tasmania

Headwater streams represent a major link between the terrestrial ecosystems and aquatic systems, but these ecological linkages are poorly documented. Headwater streams are a major component of a catchment, where they typically contribute in excess of 75% of the length of a river system. They are closely connected to riparian vegetation and upland terrestrial systems, and are subject to large volumes of allochthonous (terrestrial) organic matter and nutrients relative to stream size. Any alterations to the riparian vegetation and upland terrestrial systems, such as what happens in forestry operations, may have strong effects on the retention and breakdown of carbon, nutrient cycling and sediment transport of headwater streams.

Currently, forestry guidelines in Tasmania involve clear-burn-and-sow (CBS) harvesting with a 10 meter exclusion zone around headwater streams, but still include the harvesting of riparian vegetation where practical. These guidelines provide a mechanism that may cause changes to the flux and pools of nutrients between upland areas and headwater streams. Quantifying the flux of essential nutrients into headwater streams after CBS operations and the ability of in-stream biota to retain or store nutrients is critical, and will provide a measure of the impact that silvicultural operations may have upon ecosystem functioning and a catchment’s overall health.

The overall project objective is to assess changes to headwater stream nutrient and carbon dynamics, in-stream habitat, water quality, and riparian vegetation before, during and after forestry operations (under the Forest Practices Code) using a BACI (Before-After-Control-Impact) experimental design. This will enable me to evaluate the effectiveness of current and proposed forest practices in protecting the ecosystem functioning and habitat structure of small, headwater streams in tall, wet forests subject to harvesting and regeneration to tall, wet native forest.

Before starting my project I completed my undergraduate degree in Natural Resource Management (Hons) at the University of Western Australia. My honours project investigated the spatial distribution of surface litter in the northern Jarrah forest of Western Australia, which was supported by the Bushfire CRC and supervised by Dr Matthias Boer and Dr Pauline Grierson.

My supervisors are Assoc/Prof Leon Barmuta (School of Zoology, UTas), Dr Regina Magierowski (School of Zoology, UTas), and Dr Neil Davidson (School of Plant Science, UTas). My PhD research is funded by the CRC for Forestry and Forestry Tasmania.

My research contributes to the Trees in the Landscape research program of the CRC for Forestry.