Carlos Martínez-Núñez: Interaction networks, agricultural management and landscape

Carlos Martínez-Núñez
Carlos Martínez-Núñez

Carlos Martínez-Núñez, a PhD candidate at the University of Jaen, tells us about his paper “Interacting effects of landscape and management on plant–solitary bee networks in olive orchard”, why this paper is potentially important for policy makers, and why working with others is one of the best things you can do as an ecologist.

About the paper

What’s your paper about?

In this paper, we explore how the interplay between agricultural management and landscape complexity affects plant-solitary bee interaction networks in olive orchards. This is very important because European agri-environmental measures (AEM) aimed to recover biodiversity are sometimes not efficient. Understanding how landscape complexity shapes plant-pollinator networks and regulates AEM effectiveness might lead to a deeper knowledge of biodiversity responses to multiscale environmental changes, and provide stronger foundation for decisions makers. In addition, olive trees are pollinated by wind and consequently, pollinators are usually neglected in this important agroecosystem. We remark here pollinators’ importance and provide valuable information to fight the global decline of pollinators in agricultural systems. Finally, this paper helps to understand underlying processes that might explain interacting effects of landscape complexity and agricultural practices on biodiversity and ecosystem services.

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

Organic olive orchard
Organic olive orchard

Surprisingly, not much literature approaches applied ecological issues from the perspective of interaction networks. We could find only one paper (Power and Stout from 2011) dealing with the effects of agricultural practices on pollination network metrics. However, this is an active field in ecology and an increasingly number of applied studies using interaction networks are being published. To my knowledge, this is, however, one of the first works to test interacting effects of management and landscape complexity on pollination network variables.

What are the key messages of your article?

We send several key messages, such as the importance of studying permanent agroecosystems, the significance of pollinators even in wind pollinated cultures, the relevance of studying interaction networks, etc… However, the main result drawn from our study is that olive farms managed under organic guidelines (i.e. farms that maintain ground herb cover and do not use pesticides) in relatively complex landscapes (i.e. heterogeneous landscapes) host more diverse, stable and heterogeneous plant-solitary bee networks. Importantly, we did not find differences between organic and intensive farms located in simpler landscapes. This remarks the need to promote heterogeneous landscapes and shows how landscape can modulate the effects of agricultural management in this agroecosystem.

Who should read your paper?

Hopefully, this paper inspires people from different fields. I think it is interesting from a methodological point of view, but it mainly aims to draw the attention of applied ecologists, because the obtained results are potentially applied to the conservation of olive orchards. Maybe more importantly, we want to contribute to inform policy makers about the actions needed to achieve a sustainable agriculture that ensures the environmental and economic stability in the long run for olive orchards. Ideally, a new CAP (European Common Agricultural Policy) should include policies that embrace all the new knowledge (including papers like ours), to achieve sustainable agroecosystems (in this case, pollinator-friendly olive orchards).

About the research

What is the broader impact of your paper?

It points out that not only local management matters to understand effects of local changes on interaction networks, but it is key to take landscape heterogeneity into account. It also exemplifies how interaction networks can evidence relevant patterns that are obscured when just focusing on species abundance or richness. In our paper, we show how switching from intensive to organic management, does not improve plant-solitary bee networks unless there is a surrounding heterogeneous landscape.

Did you have any problems setting up the experiment or gathering your data?

Complex landscape
Complex landscape

Working in agroecosystems is extremely challenging because we rely on farmers that have economic interests on the study system. Therefore, despite some of them are absolutely involved and helpful with our research, some others, understandably, put their economic interests before the study, which might cause some noise and inconveniences. That is why it is very important to have a good relationship and keep a good communication with farmers. After all, they generously welcome us to their properties. We also faced important challenges due to the wide geographical range that we cover across all of our study sites. For instance, we needed to plan samplings very carefully, because phenologycal mismatches between distant farms might affect the results.

Thankfully, we have a good communication with the farmers we work with, and have been able to plan the sampling carefully. Therefore, the field seasons have so far been enjoyable and successful.

What would you like to do next?

I would like to study other ecosystem services such as seed dispersal or natural pest control in this same theoretical framework (local management and landscape complexity interplay), and see whether observed patterns for pollination can be generalizable to several ecosystem services or not. I suspect that contrasting effects of management on different animal groups, and the way different groups perceive landscape heterogeneity (and its scale), might lead to different outcomes for ecosystem services that rely on different groups of animals (e.g. pollination by insects or seed dispersal by birds).

About the author

I am currently a PhD candidate at the University of Jaen, working in Pedro Rey’s lab. Being part of this excellent group and big project is both challenging and exciting. After some papers focusing on pollinators, I am now moving to study effects of local management and landscape on ecosystem services related to natural enemies and pest control. Specifically, I am focusing on experimental approaches to elucidate the contribution of insectivorous birds to pest control in olive orchards.

What I like the most about my job is that I face intellectual challenges every day. These are quite complex systems and there is always something new to think/learn about. Moreover, I personally feel fulfilled because I am working on issues that I deem very important for the conservation of nature and for human societies.

My piece of advice to other scientists would be: try to collaborate with others, because I think it is very enriching and enjoyable. Also, novel ideas often come from talking with other scientists (sometimes from other areas). I also think that ego is the rotten tomato of science, so ignoring it is, in my opinion, the best thing you can do.

Read the paper here and the free plain language summary here.

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