21 February 2024

Ants offer new guidance on biodiversity in biofuel crops

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Effects on the communities of ants are one example of the consequences of energy policies and subsequent land use change, a study from U.S. has found

by Matteo Cavallito

 

Biodiversity loss is considered a possible side effect of intensive cultivation aimed at biofuel production. Some policy choices, however, can help achieve a better balance by limiting the fallout for ecosystems. But what to decide among the various alternatives available? One possible answer may be offered by some unsuspected actors: ants.

This is suggested by a research from U.S. published in the journal Frontiers in Conservation Science. By comparing insect communities in different types of cropping systems, the authors were able to understand how these systems model biotic communities and their functions.

Why ants?

Particularly prevalent in pastures and agrosystems, the researchers recall, ants “can be important predators, seed dispersers, and soil engineers.” That is, perfect candidates for providing useful insights into the impact of crops on insect communities.

“There are a wide range of cropping systems that have not been widely deployed yet but could become commonplace, and our knowledge of their ecological attributes and biodiversity impacts is limited,” the research explains.

Ants, the study continues, “are prominent and functionally important components of grassland and agricultural ecosystems. Given their outsized influences on ecosystem structure and function, we sought to understand how ant communities are likely to be shaped by a range of bioenergy cropping systems.”

Crop choices impact ecosystem functions

The researchers then examined ten cropping systems in an experimental field in Michigan. These included annual crops (corn and two types of broom), simple multi-year perennial systems (two grasses, miscanthus, and a mix of native grasses), and diverse perennial systems (reconstructed prairie, wild vegetation, and a short-rotation coppicing system with aspens).

In complex ecosystems, ants played more functional roles in comparison with simple systems.

“Perennial bioenergy cropping systems, particularly those that incorporate more plant diversity, give rise to a different and more diverse ant community than simpler systems” explained Nathan Haan, researcher at University of Kentucky and co-author of the study in a statement released by the scientists. In short, the results, the study further notes, illustrate “the divergent effects that bioenergy crop adoption could have for ant communities and the important functions they carry out in agroecosystems.”

Looking for a compromise

The crops tested have different pros and cons for biofuel production. Some, for example, are more productive but provide little benefit for biodiversity conservation. Others, such as mixed species, seem to provide opposite indications. “It’s a matter of understanding trade-offs and figuring out how to optimize them,” Haan explains. That is, identifying “which of these cropping systems are biodiversity-friendly and which are not.”

The study can thus provide an important perspective. Indeed, the very ants, the research concludes, “exemplify the range of outcomes that could come to bear as the result of future bioenergy policies and the land use change that follows.”

In the United States, biofuel production relies primarily on corn (about 40 percent of its crop goes to the ethanol industry each year). Within this framework, however, “Expanding the footprint of corn will result in a number of undesirable outcomes including nutrient pollution, landscape simplification, increased insecticide use, and biodiversity loss.” Fortunately, the study concludes, it is possible to incorporate perennial crop systems into simplified agricultural landscapes, improving biodiversity and associated services.