Evidence for ecosystem engineering in a lentic habitat by tadpoles of the western toad |
| |
Authors: | Sylvia L R Wood John S Richardson |
| |
Institution: | (1) Department of Forest Sciences, University of British Columbia, 3041–2424 Main Mall, Vancouver, BC, V6T1Z4, Canada;(2) Department of Geography, McGill University, 509–850 Sherbrooke St.West, Montreal, QC, H3A2K6, Canada |
| |
Abstract: | A number of aquatic organisms have demonstrated an ability to modulate sediment deposition in tropical and temperate stream
systems, but little is known about the impact of similar benthic grazing processes in temperate pond systems. Using exclosure
experiments in mesocosms, we used tadpoles of the western toad (Anaxyrus boreas) to investigate two questions: (1) can grazing activities of tadpoles of the western toad in ponds reduce sediment accrual
on grazing surfaces (e.g. via bioturbation or ingestion); and (2) do these grazing activities contribute to enhanced periphyton
biomass and chlorophyll a content of benthic matter. Mesocosms received pulses of fine sediment weekly over 8 weeks to simulate allochthonous surface
inputs following rainstorms. Accumulated sediment and periphyton matter on exposed and grazing-restricted substrate surfaces
were measured weekly. Tadpole grazing activity significantly reduced the standing stock of periphyton on open grazing surfaces
by 80% in controls. Under sediment-additions, tadpoles effectively removed settled particulate matter from exposed grazing
surfaces, but no corresponding increase in periphyton biomass was observed. These results suggest that tadpoles can impact
the dynamics of sediment distribution in ponds as well as streams, providing support for a role as “ecosystem engineers” in
these habitats. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|