EESS talk on "Better understanding stream ecological processes through scale considerations"
Event details
Date | 25.10.2016 |
Hour | 12:15 › 13:15 |
Speaker | Dr Janine Rüegg, SBER |
Location | |
Category | Conferences - Seminars |
Abstract: Stream ecological processes such as primary productivity or biomass are influenced by the environmental context, meaning the physical, chemical and biological properties of the stream environment. Changes to the environmental context, be it internal, such as changes to the stream food web, or external, such as changes in resource subsidies to stream ecosystems, will affect ecological processes. However, the effects of such changes may be spatially and temporally limited or distinct to a specific scale. In this talk, I will first present how the consideration of scale enhanced our understanding of an external change, namely the use of salmon spawner resources by stream biofilms. The data collected represent different spatial and temporal resolutions that resulted in different interpretation of the importance of salmon spawners to stream biofilms and thus ecosystems. Secondly, I will present how the decrease of large-bodied consumer, mainly fish, affected stream ecological processes at two distinct spatial scales of manipulation (dm2 and 10s of m2), as well as how modeling may allow us to extrapolate experimental outcomes to even larger spatial scales. Experimental manipulations are difficult to maintain, especially at larger spatial scales, and knowledge of how natural or manipulative experiments vary with its scale will allow for the correct application of smaller scale experiments to the larger management scales.
Short biography: Dr Janine Rüegg's research focuses on the context dependency of ecological processes in stream ecosystems. That context includes a careful consideration of both spatial and temporal scale. She has studied context dependency and scale in many stream ecosystems (coastal to alpine and tropical to arctic) and based on a variety of responses (ecosystem rates, biofilm, macroinvertebrates, fish). To highlight just a few research findings: 1) Ecosystem rates in streams responded to the removal of large-bodied consumers, such as fish, shrimp, or salamanders, but responses depend on the density of consumers, as well as the scale of the experimental manipulation (1 m2 or 10-100s of m2). 2) Biofilm responses to the nutrient subsidy of and physical disturbance by Pacific salmon spawners depended on environmental conditions among streams and across years including the timing and magnitude of the salmon runs. However, an adequate description of the biofilm responses to salmon spawners required high-frequency measurements of biofilm, salmon, and physio-chemical parameters that allowed for modeling of the salmon-biofilm interaction within the context of environmental conditions. 3) Macroinvertebrate species assemblages depended on the hydrologic and temperature regimes of alpine streams. On her current SNF Ambizione funded project, she is focusing on food webs as a whole, and how their structure and function is determined by the environmental fluctuations of light, temperature, and discharge as well as carbon subsidies (organic matter inputs from outside the stream).
Short biography: Dr Janine Rüegg's research focuses on the context dependency of ecological processes in stream ecosystems. That context includes a careful consideration of both spatial and temporal scale. She has studied context dependency and scale in many stream ecosystems (coastal to alpine and tropical to arctic) and based on a variety of responses (ecosystem rates, biofilm, macroinvertebrates, fish). To highlight just a few research findings: 1) Ecosystem rates in streams responded to the removal of large-bodied consumers, such as fish, shrimp, or salamanders, but responses depend on the density of consumers, as well as the scale of the experimental manipulation (1 m2 or 10-100s of m2). 2) Biofilm responses to the nutrient subsidy of and physical disturbance by Pacific salmon spawners depended on environmental conditions among streams and across years including the timing and magnitude of the salmon runs. However, an adequate description of the biofilm responses to salmon spawners required high-frequency measurements of biofilm, salmon, and physio-chemical parameters that allowed for modeling of the salmon-biofilm interaction within the context of environmental conditions. 3) Macroinvertebrate species assemblages depended on the hydrologic and temperature regimes of alpine streams. On her current SNF Ambizione funded project, she is focusing on food webs as a whole, and how their structure and function is determined by the environmental fluctuations of light, temperature, and discharge as well as carbon subsidies (organic matter inputs from outside the stream).
Practical information
- General public
- Free
- This event is internal
Organizer
- EESS - IIE
Contact
- Prof. Tom Battin, SBER