Welcome to TRivers!
LIFE TRivers studies the hydrology and ecology of temporary rivers and aims at creating new tools to improve their management according to the objectives of the EU Water Framework Directive (WFD). The project will contribute to the conservation and restoration of one of the most common river typologies in the Mediterranean Basin, which contains most of Europe´s threatened freshwater biodiversity.
Trivers at the Outreach workshop in Els Ports Natural Park (Catalonia)
Collaboration between managers and researchers is a key element for improving the understanding and management of ecosystems, and especially in temporary rivers due to their lack of recognition by society. The relationship between the TRivers project and Els Ports Natural Park is an example of this interaction, as shown during the Outreach workshop organized on November 15th by Els Ports Natural Park in Tortosa (Catalonia). Núria Cid, researcher from the Department of Evolutionary Biology, Ecology and Environmental Sciences of the UB and member of Life TRivers presented the results of the project, focusing on those rivers located in Els Ports.
The headwaters of the Canaletes and Algars rivers, both located in the Els Ports Natural Park, and the Cérvol river, at the Tinença de Benifassà Natural Park, are studied by TRivers because of their good conservation status. Thus, in these systems biological communities of permanent and temporary rivers can be compared without the influence of human impacts and be used as reference.
From April to September 2015, TRivers researchers carried out five sampling campaigns in these rivers, showing different results: "We observed that, on the one hand, both Canaletes and Algars rivers presented a permanent flow at the headwater, but flow disconnected during summer at the stream reaches located downstream. On the other hand, in the Cérvol river flow was present during in spring and the riverbed was totally dry in August."
As a result of this research, Núria Cid highlighted the importance of adapting the sampling calendar and sampling location in naturally temporary streams and use current sampling methods only in that period with the highest chance to find the river in flowing conditions and when all the habitats are still connected. This situation can be detected using the TREHS software, developed by the TRivers project. The software uses different information sources, such as measured water discharge from gauging stations, simulated flow data, interviews with locals and aerial photographs. Regarding ephemeral streams, Núria Cid proposed the development of alternative methods.
Detecting the impact of water withdrawals
The study also included reaches of permanent rivers that become temporary due to hydrological impacts such as water abstraction. These rivers correspond to the lower Matarraña river, and the Sénia river. For example, in the Matarraña, only isolated pools are left during summer, affecting populations of many aquatic organisms such as native fishes, most of them threatened. According to the presented results, biological quality in these rivers decreased mainly due to the hydrological impact. Therefore, it is highly relevant detecting the current hydrological impacts to establish ecological flows. Only with this effort we will be able to maintain the biological quality of rivers following the EU Water Framework Directive and conserving the high freshwater biodiversity hold by Mediterranean streams and rivers.
During the workshop, related studies were presented. For example, the results from the dragonfly and damselfly monitoring program conducted in Els Ports Natural Park by Pere Luque, biologist at the Terres de l'Ebre Museum. It was discussed whether populations of the dragonfly Macromia splendens, a protected species that needs permanent rivers to complete its life cycle, could be negatively affected by flow reduction in the near future due to present and planned water abstraction and/or climate change.
In this sense, Núria Cid highlighted the relevance of studying temporary rivers and ephemeral streams, because "streams and rivers in areas with Mediterranean climate will receive less and less water under climate change and, therefore, temporary rivers will become more frequent."
Gemma Burgazzi: "Understanding temporary rivers' dynamics is crucial for their conservation"
Gemma Burgazzi is PhD researcher at the Aquatic Ecology Lab of the University of Parma. Her research is focused on freshwater macroinvertebrate communities and their responses to flow modifications. In particular she studies the diversity and distribution of taxa in different types of ecosystems across environmental gradients. The aim of the project is to understand the effects of flow variations due to dams and water withdrawals and provide useful information for maintenance of river ecosystem. From March to April, Gemma was in Barcelona working with TRivers project. In this interview, she shared with us her experience during her stay and her views about the importance of studying temporary rivers.
Could you briefly describe the objectives of your PhD?
My PhD is focused on the study of macroinvertebrate communities' dynamics in rivers with different degrees of intermittence and at different spatial scales. I'm trying to investigate which are the main drivers of the communities and how they evolve in time.
Why and how did you get interested in these issues?
I started to work with macroinvertebrates during a stage in an environmental agency after my bachelor degree and then I got interested on the effects of water variations and intermittence during my master thesis. Therefore, it started almost by chance, but then these arguments intrigued me more and more and I brought them forward with the PhD.
How important is the role of freshwater macroinvertebrate communities in river ecosystems and the study of their condition?
I think the study of macroinvertebrate communities is essential because they are one of the best and more suitable proxies for understanding the health state of a river.
Why did you choose the TRivers project to do your research stay?
During my work, I read a lot of papers published by people from the F.E.M. group, so I contacted them for my PhD mobility program. When they told me about the TRivers project I realized that it was perfect for improving my knowledge for my PhD topics.
What kind of work have you done during your stay here?
During my stage in the F.E.M. group, I studied the relations between the local environmental conditions, the time of disconnection of the habitats inside the rivers and the macroinvertebrate community structure.
What are the main take-home messages of your stay?
Working in the TRivers project, I learned an easy and precise method for detecting the disconnection time of river habitats, in addition to an improvement of my knowledge about temporary river ecology.
How will you apply this knowledge to your PhD?
The method I learned during my stage will be applied for a part of my PhD project where I will study the longitudinal variation of water permanence in rivers and the relative variation of macroinvertebrate communities.
What would you like to highlight about your stay?
During my research stay I worked in a highly skilled and collaborative group, with a lot of other PhD students so I had the chance to meet, discuss and exchange ideas.
Why do you think is important to do research about temporary rivers?
From my point of view improving the understanding of temporary rivers is a crucial point because this kind of systems is increasing all around the world (for the effects of climate change and anthropogenic impact), with many rivers undergoing hydrological regime shifts. Therefore, understanding their dynamics and the response of biotic communities is fundamental for the maintenance of these ecosystems and the high levels of biodiversity they support.
Could you highlight any aspect about temporary rivers that you didn't expect to find before coming to Barcelona?
In addition to the new method that I learned in the University of Barcelona, I also learned how the environmental and geographical context is important in determining the characteristics of the temporary rivers.
What has been your experience during the stage?
Besides the work on the TRivers project, I did also several sampling and laboratory activities and I attended to some seminars and research group meetings. This stage gave me the opportunity to work with people from different countries and with different competence and I think this is a really valuable experience for a young researcher.