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Irene Vega
Pollinating insects play a fundamental role in plant reproduction and, without their presence, the restoration of semi-natural environments, such as grasslands, may not achieve the desired results. To solve possible adverse results, an international scientific team has evaluated the reproductive performance of plants pollinated by insects, also taking into account their relationship with the green infrastructure in which they are located. “The solution is not limited to simply eliminating the shrubs and trees that occupy grasslands when herbivores are missing. It is also crucial that pollinating insects return,” says Carlos Lara Romero, researcher at the URJC and co-author of the study, published in the journal Journal of Applied Ecology.
To carry out this research, 24 ancient and restored grasslands distributed in Sweden, Germany and Belgium were selected, representing European geographical diversity. In addition, the influence of the surrounding green infrastructure was observed, such as crop edges and roads with remaining grassland and forest margins.
The results obtained reveal that the restored grasslands are made up of more exclusive (specialized) communities with more specific connections between plants and pollinators, mainly bees and butterflies. “This discovery suggests that, in terms of functionality, restored grasslands could be less redundant (that is, less resistant) than their ancient counterparts,” explains the URJC researcher, adding that “the study also provides solid evidence that “The presence of green infrastructure in the surrounding landscape is a key factor influencing both the amount of pollination service and the composition of pollinator species.” Specifically, “a reduction in green infrastructure translates into simpler pollination networks that are less robust to future disturbances,” says Anna Traveset, the IMEDEA (CSIC-UIB) researcher and leader of the article.
Solutions to recover the biodiversity of grasslands
Livestock activity through traditional grazing has maintained the semi-natural grasslands of Europe, thus conserving the very high biodiversity of these ecosystems. However, these landscapes are threatened by agricultural intensification, forestation and the abandonment of agriculture, causing a loss of biodiversity. To carry out a successful recovery of these environments, this work highlights the importance of the landscape context in restoration programs, since it significantly influences the interactions between plants and pollinators. As Carlos Lara Romero points out, “the design of restoration programs must carefully consider the landscape context to promote a robust and resistant pollination network. To prevent generalist species from taking over from specialists in the restored grasslands, we suggest reinforcing the presence of specialist species in these by increasing connectivity with the populations of origin.”
“These recommendations are not only relevant for the conservation of European semi-natural grasslands and the pollination service they provide, but may have implications for the conservation and restoration of similar ecosystems in other regions, that is, on a more global scale. ”concludes Traveset.