Biological variation in temporary streams: understanding river patches at different scales for monitoring and management applications

Sroczynska, Katarzyna Krystyna

http://hdl.handle.net/10400.1/10794

Use this identifier to reference this record.

Name:	Description:	Size:	Format:
Sroczynska_PhD_final.pdf		17.69 MB	Adobe PDF	Download

Send Feedback

Authors

Sroczynska, Katarzyna Krystyna

Advisor(s)

Chícharo, Luís

Wojtal-Frankiewicz, Adriana

Abstract(s)

Biota and ecological processes are highly complex and vary at every scale. This underscores the importance of employing a multi-scale design to adequately understand these processes and complex relationships in riverine ecosystems. In addition, there is a strong need to develop appropriately scaled indicators of river ecosystem health that include this biotic complexity in a manageable fashion. Unfortunately, currently available indicators are either too complex or do not adequately capture the highly variable changes to the ecosystem. Patches are good templates for various ecological processes and because they are considered to be stable over the spatial and temporal scales, they can be used as functional filters of important processes in streams. The aim of this thesis is to employ patch theory and multi-scale approach to develop structural and functional indicators of the ecosystem health at the patch level and evaluate in which of the scales these indicators are of the highest relevance for the patch. The system at which these indicators were tested consists of headwater intermittent streams within a Mediterranean catchment. Three scales were considered: reach scale, stream scale and catchment scale. According to the results patch as a source of variation was not well explained by the structural measures of benthic communities at catchment scale. This was related to the effect of occurrence of a strong environmental filter (mainly altitude and its association with conductivity and temperature), which limited distribution of biota and constrained the occurrences of certain species at the smaller scales. Also, these filters were demonstrated to act indirectly through patterns in habitat formation and availability. Patch investigated at the reach scale provided slightly more predictable unit of species organization, nonetheless, still benthic communities of some of the patch types overlapped. Instead, the most consistent measures of ecosystem health that could be applied to studying patches were the metabolism measurements at the reach scale and the isotopic signatures at the stream scale. Next step forward would be to establish reference values for these two approaches for undisturbed systems, and subsequently to incorporate these measures into biomonitoring guidelines. Following disturbance, patches have been shown to be the most appropriate unit used when evaluating biotic recovery. As such, this study represents an important step towards development of better biomonitoring tools as well as evaluation of the restoration effort.