The journey is as important as the destination:  autumn-leaves as the main food source for stream communities

In this Insight, Manuela Abelho discusses her recent paper, Litter movement pathways across terrestrial–aquatic ecosystem boundaries affect litter colonization and decomposition in streams.

About the research

How did you come up with the idea for it?

There is an enormous amount of leaves which accumulate each year in riparian areas. Some of these leaves eventually enter streams, but, as far as I know – nobody studied decomposition of leaf litter as it flows from the riparian area to the water. I noticed this gap of knowledge and I had the idea of designing an experiment to see how leaf litter decomposition proceeds along the terrestrial-aquatic continuum.

Did you have any problems gathering your data?

Because I do not work with a team, I have not much help for field or laboratory work. Thus I had to use my brother to help during the experiment.

How is your paper new or different from other work in this area?

The main difference is that it focuses on the meta-ecosystem. Despite the enormous amount of data gathered on leaf litter decomposition in terrestrial and in aquatic ecosystems, as far as I know, this is the first study assessing decomposition of leaf litter along a gradient of terrestrial-aquatic conditions.

Where you surprised by anything when working on it?

I was very surprised to find out that a period of terrestrial decomposition dramatically inhibits the colonization of leaf litter by aquatic hyphomycetes once this leaf litter reaches the water. Until now, all discussions about leaf litter processing in streams were based on leaves that decompose only in water. This adds knowledge to the field because we now know that leaf litter that reaches the water after starting decomposing in the terrestrial environment does not behave in the same way as leaf litter only decomposing in water. This may change what we think we know about stream processes.

Now that this paper has been published, what is the next step?

I think that our paper opens the way for a more integrated study of meta-ecosystems such as streams and their riparian areas. Also, we will need to find answers for the observed differential aquatic hyphomycete colonization of litter decomposing both in the terrestrial and in the aquatic ecosystem and only in water.

About the Author

How did you get involved in ecology?

That was a long time ago! In fact I graduated as a Biologist specialized in Physical Anthropology with the dream of studying human evolution. However, by then I could find no opportunities to continue my studies in that area, and in 1992 I finally enrolled in a master programme in ecology and I continued involved in ecology ever since.

I started doing research by studying stream ecology, and I was always very interested on litter processing in streams. I’ve been studying organic matter decomposition in streams ever since. Enrique has been studying aquatic hyphomycetes – the main aquatic decomposers of leaf litter in streams – all his (already long) life.

What’s your current position?

I am a professor at the Agriculture School of Polytechnic Institute of Coimbra, Portugal, where I am also the International Relations Coordinator. Most of my time is dedicated to teaching and to organizational activities. Thus, although I am also a researcher at Centre for Functional Ecology, my research has been scarce in the last years.

What do you do in your spare time?

I love travelling, trekking in nature, and nature photography, and I often do that in my spare time.

You can read Manuela’s paper here: Litter movement pathways across terrestrial–aquatic ecosystem boundaries affect litter colonization and decomposition in streams.