Full Title
Food resources in a small stream; effects of native, Salix spp. and Salix spp. removed riparian zones on instream food webs in little Snowy Creek.
Student
Louise Menz
Supervisor
Paul McInerney
Rob Cook
Funding Body
MDFRC
Duration
10 weeks November 2009 to February 2010
Outcomes
Written report and verbal presentation.
Summary
In Australia willows (Salix spp.) are viewed by researchers as weeds that pose a serious threat to stream and wetland environments due to their highly invasive and adaptive qualities . A widely accepted view has emerged that fundamental stream ecological processes may be affected by the spread of willows, causing a broad range of detrimental impacts to freshwater ecosystems. As such many natural resource managers now have a focus on willow removal from catchments without fully understanding the implications for ecosystem health.
Willow studies have historically focused on allochthonous (leaf litter) inputs, leaf breakdown rates, canopy cover, stream shading and temperature and macroinvertebrate feeding preferences. In Australia, previous studies on willow effects have included comparisons of willow and native leaf pack decomposition and colonisation and field surveys of aquatic biota and thermal changes at willow and native forest lined reaches. Few studies have actually examined or quantified the impacts of willows or willow removal on in-stream fauna, despite reviews by various authors.
This project will focus on examining the differences in food resources and resource use between reaches of stream dominated by Salix spp. and native vegetation along with reaches that have recently had all Salix spp. removed. Techniques will include stable isotope analysis of food resources and primary consumers, macroinvertebrate biomass, algal/biolfilm biomass and colonisation rates and leaf litter/organic matter biomass.
