Influences of agricultural landuse and seasonal changes in abiotic conditions on invertebrate colonisation of riparian l
- PDF / 595,936 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 66 Downloads / 258 Views
Aquatic Sciences
RESEARCH ARTICLE
Influences of agricultural landuse and seasonal changes in abiotic conditions on invertebrate colonisation of riparian leaf detritus in intermittent streams David J. Reid • P. S. Lake • Gerry P. Quinn
Received: 23 September 2011 / Accepted: 2 August 2012 / Published online: 26 August 2012 Ó Springer Basel AG 2012
Abstract The structure and function of agricultural stream reaches with sparse riparian and floodplain vegetation differ from those of forested reaches, but may be ‘reset’ as these streams flow through reaches with forested riparian zones. We investigated whether invertebrate colonisation of River Red Gum (Eucalyptus camaldulensis) leaf packs in lowland intermittent streams was influenced by the adjacent reach-scale landuse (cleared farmland or forested reserve) within an agricultural catchment in Victoria, Australia. Further, we examined the influence of seasonal changes in hydrology and associated changes in abiotic conditions on the colonisation of leaves by repeating experiments over two summers and one spring. Across these experiments, there were no consistent differences in the structure of communities that colonised leaves in farmland and reserve reaches. In both seasons, most leaf colonists were collectors and few were shredders in both farmland and reserve reaches. Relative abundances of gastropod grazers were much higher in summer than in spring. The structure of invertebrate communities colonising leaves in the different reaches converged over time
D. J. Reid (&) P. S. Lake School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia e-mail: [email protected] G. P. Quinn School of Life and Environmental Sciences, Deakin University, Warrnambool, VIC 3280, Australia Present Address: D. J. Reid 560 Riverside Drive, Apt 2A, New York, NY, USA
when streams flowed in spring, but diverged over time as the streams dried and abiotic conditions within disconnected pools became increasingly harsh in summer. Thus, patterns of leaf pack colonisation were influenced by the regional climate causing large seasonal changes in hydrology, but not by reach-scale landuse. The large-scale disturbances of agricultural landuse across the catchment and a supra-seasonal drought probably contributed to low diversities of invertebrate communities in the streams. Keywords Detritus Leaf pack Riparian Hydrology Functional feeding group Multiple stressor
Introduction The replacement of native overstory vegetation with crops or pasture can cause large changes to the structure and functioning of streams flowing through agricultural landscapes (Allan 2004). Those changes to resource availability and abiotic conditions which most influence invertebrate communities include significantly lower allochthonous detrital inputs, and increases in autochthonous production, nutrient inputs, sedimentation, temperature fluctuations and flow variability (e.g. Dance and Hynes 1980; Bird and Kaushik 1992; Hagen et al. 2006). Experimental leaf pack studies in permanent str
Data Loading...
