Spotlight: Managing biodiversity and ecosystem services in farmland landscapes

Issue 56:1 of Journal of Applied Ecology turns its focus to innovative developments in sustainable food production with the Spotlight, Landscapelevel design for managing biodiversity in agroecosystems. Associate Editor, Tomas Pärt and colleagues from The Landscape Ecology Network group at the Swedish University of Agricultural Sciences summarize the importance of this new collection of work.

oilseed-rape-642406_960_720How should we use and manage agricultural landscapes for sustainable food production? Farming provides us with food and other goods that depend in some way or another on the diversity of a range of organisms that live in farmland and in the surrounding landscape. Changes in agricultural practice during the past 60 years have had serious effects on these species and the vital services that they provide. This has driven an interest from the general public, the research community, politicians and practitioners into how to manage rural landscapes in a way that is sympathetic for biodiversity, whilst still also growing the food we need and ensuring farmers’ livelihoods. We, the Landscape Ecology Network at the Swedish University of Agricultural sciences spend a lot of time looking into these very issues, and thought that it would be an interesting and pretty straightforward task to summarize the eight papers that have been brought together for this Journal of Applied Ecology Spotlight on ‘Landscape-level design for managing biodiversity in agroecosystems’. However, as you will learn from this post, this mission was not as direct as we first imagined.

At first glance, it seemed like there would be no easy way to synthesize all the valuable insights presented in this range of studies. The authors address many burning issues and debates about how to manage farmland; from new perspectives on the old land sharing vs. land sparing arguments to the more recent focus on the need for farmer participation as a crucial element for landscape-level conservation. At the same time, the studies also brought fresh insights from regions, habitats and study species that have largely been underrepresented in the literature. It was a challenge, but after reading the papers, we did find a number of common themes of general relevance for biodiversity conservation in agricultural landscapes.

How can wildlife and food production co-exist in the same landscape?

The land sharing vs. land sparing strategies of biodiversity conservation remains a contentious issue in farmland landscapes. Land sharing, i.e. reducing the intensity of land use and thereby producing food and preserving biodiversity on the same piece of land, has been highlighted as a sustainable way to combine food production and biodiversity, but this has often been countered by the view it is best to keep natural habitats separate from areas primarily used for agricultural production. Balmford et al.’s study of biodiversity in the farmlands of Ghana and India adds an extra level of complexity to the debate by highlighting the (likely common) situation of imperfect land sparing, where spared land is of low quality or inadequately protected. Nonetheless, by relating agricultural yield with bird and tree populations, the authors conclude that even when land sparing is imperfect, the positive effects almost always surpass those of land sharing. The study therefore adds further weight to the argument that we need to increase protected areas in agricultural landscapes. However, it is interesting to note that many common species also benefited from land sharing strategies, while the benefits of land sparing were mainly restricted to rare and uncommon species. As evidence suggests that important ecosystem services are often provided by more common species in a landscape, we believe that this is not the last word in this interesting debate.

pitfall trap - botzl
Pitfall trap in place in oilseed rape. Photo by Fabian Bötzl

This issue moves us to Europe, where Gallé et al. explore a land sharing solution by comparing carabid and spider functional diversity for the potential benefit to ecosystem services, including weed-seed predation and pest control at organic and conventional farms with different landscape compositions. The study shows that organic farming relates to higher carabid functional diversity, and demonstrates the general benefits of crop field edges. These results generally suggest that high landscape configurational heterogeneity and reduced intensity of farming practices may be beneficial for natural pest control. Similarly, Boetzl et al. investigated the effects of different types of grassland including agri-environmental schemes on predatory arthropods in adjacent oilseed rape fields. They found that arthropod species spill over from grasslands into adjacent fields. Although not specifically designed to address land sharing and land sparing, the study does highlight the benefit of having high quality natural habitats present within farmed landscapes.

A final example of the benefits of land sparing in this spotlight was Luke et al.’s much-needed Policy Direction on riparian systems in tropical farmlands. Here, the importance of river buffers for both ecosystem services (not only the hydrological aspects but also for nutrient retention and reduced nutrient leakage) and biodiversity conservation. This paper also encourages us to think in terms of large-scale habitat connectivity in both aquatic and terrestrial elements of farmland landscapes. Importantly, it also identifies a number of key components needed to implement effective riparian policies in tropical regions.

What do the farmers think?

Including farmers in the design of sustainable practices may seem like an obvious way to encourage feasible and successful biodiversity management in agricultural landscapes. Still, such multi-stakeholder approaches to research and policy are only recently being implemented. As of yet, we are not aware of too many examples of such approaches, but Runge et al.  do provide evidence of how problems can arise from a lack of communication between different stakeholders. This study highlights a situation where restrictions on grazing pressure in the public rangelands of the western United States, enforced with the intention of improving biodiversity actually led to a reduction of diversity because farmers were left with no choice but to abandon animal farming entirely for economic reasons. This then had the knock-on effect of private pastures being converted to arable fields, with further implications for species dependent on grassland habitats in the area.

This illuminating case study convincingly shows that farmers must be consulted early in the planning processes of biodiversity conservation.

Fortunately, Berthet et al.’s Commentary provides some concrete ideas regarding how to involve farmers in finding new solutions for sustainable agro-ecosystems. They stress the need to investigate the potential of integrating ecological knowledge in a participatory manner to better balance biodiversity conservation and agricultural production. One important message from this collection of examples is that farmers should be engaged in building and exploring novel practices that are based on ecological knowledge. This kind of approach not only strengthens a farmer’s sense of ownership and responsibility for implementing management practices, but can also result in collaborative solutions that are sustainable from ecological, economic and social perspectives.

And what about scale (I hear you ask)?

Most papers included in this Spotlight acknowledge that many ecological processes are scale-dependent, but two articles in particular present elegant examples of how we can study the effects of scale and landscape context on farmland biodiversity. Such experimental studies are rare but extremely valuable in disentangling the processes behind observed patterns. Aristizabal et al.  investigated the effects of ants on local pest control in Brazilian coffee farms via an exclosure experiment in different types of landscapes. Interestingly, ants were capable pest predators, but their effectiveness depended on landscape structure and composition in a complex ways. The landscape-level management recommendations suggested by the authors would probably not have been possible without this kind of large-scale experimental design.

Similarly, Hansen et al. were able to draw on the results of an elegant experimental design to provide guidance for landscape management for farmland reptiles. By examining predation rates on plasticine lizards, the researchers concluded that management decisions at habitat edges would reduce edge-dependent predation rates and therefore increase landscape-scale connectivity. With so few studies of farmland reptiles, and evidently very few reptiles remaining in farmland, this study also fills an important gap in the knowledge.

What next?

Taking us on a journey around the world, these new studies show us that with process-based ecological knowledge at our disposal we can start to find new and innovative solutions to a more sustainable food production. There is still work to do, but this Spotlight gives us some hope and highlights promising future directions for researchers, practitioners and farmers towards balancing the need for food and goods with goals of maintaining biodiversity and ecosystem services in agricultural landscapes.

Read all the papers in the Spotlight, Landscape-level design Landscapelevel design for managing biodiversity in agroecosystems in issue 56:1 of Journal of Applied Ecology.

The Landscape Ecology Network group at the Swedish University of Agricultural Sciences are: Alistair Auffret, Juliana Dániel Ferreira, Matthew Hiron, Jonas Josefsson, Ineta Kačergytė, Matthieu Paquet, Ester Polaina, Tomas Pärt, Zuzanna Rosin, Erik Öckinger.

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