Restoration offers the biggest ecological benefits to grasslands

Grasslands are some of the most biodiverse ecosystems in Europe, and also play a considerable role in providing ecosystem services vital to agriculture and society, such as pollination, the maintenance of soil quality and natural pest control. Their existence largely rests on human activities such as grazing and mowing¹, but changes in land use have led to their steep decline over the last century. The largest proportion of loss is due to conversion into intensively managed arable fields, but abandonment, leading to shrub encroachment, as well as afforestation using plantation forests, have also played considerable roles².

Despite recognition of the importance of such grasslands, their destruction is ongoing. Recent years have seen tree planting promoted as a means of climate change mitigation, posing another possible existential threat to these habitats. With 95% of semi-natural grassland lost in Estonia³, researchers in the country set out to understand the impact of grassland abandonment and afforestation on the provision of ecosystem services, addressing what they saw as a lack of focus on the consideration of biodiversity in afforestation programmes.

They analysed a large data set focused on land-use change in Estonian alvars – semi-natural grasslands on calcareous bedrock. This data was gathered between 2014 and 2016 as part of the EU-funded LIFE to Alvars project. Thirty-five large historical grassland sites were selected for study, based on them having remaining recovery potential. Within the sites, areas were classed, based on their condition as either ‘open’, ‘overgrown’ or ‘afforested’ zones, creating a total of 105 subsites. To assess biodiversity in the zones, they calculated the species richness of 10 groups of organisms, ranging from vascular plants and lichens to ground beetles and birds. They also looked at how effective the habitat was in providing eight ecosystem services, using different measurement approaches.

Their analysis showed that compared to open grassland, abandonment and afforestation both contributed to declines in pollination, pest control, forage for grazing animals to eat, soil quality, the availability of wild foods and cultural appreciation of the landscape. As such, conservation of grasslands through moderate management approaches should be continued where it is practised, and overgrown areas restored, in order to provide the maximum biodiversity and ecosystem service provision.

More broadly, the researchers argue that focusing on one issue at a time, such as nature-blind climate mitigation through carbon sequestration in forest plantations, can lead to oversights around how wider ecosystems function. As an example, they found no difference in soil organic carbon content between the grassland-condition classes; but soil quality maintenance was lower on afforested sites, with these areas having significantly lower beneficial fungi diversity.

The findings suggest that afforestation of high diversity grasslands should not be considered as a sustainable climate-change mitigation strategy, due to losses through this approach outweighing gains, say the researchers. Furthermore, the data underlines key conservation principles: the more biodiverse areas are, the more effectively they are able to provide a number of vital functions for sustaining life on earth - a fundamental that applies beyond grasslands, to managing the preservation of all biodiverse habitat.

Further Information:

Such research is helpful when designing integrated approaches for climate and biodiversity, as suggested in the proposed EU Nature Restoration Law.  This study also highlights the importance of avoiding mitigation strategies relying on monocultural forest plantations, as highlighted in the proposed EU carbon removals certificatory framework.

Footnotes:

1. Pärtel, M., Bruun, H. H. and Sammul, M. (2005) Biodiversity in temperate European grasslands: Origin and conservation: 13th International Occasional Symposium of the European Grassland Federation. Integrating Efficient Grassland Farming and Biodiversity: Proceedings of the 13th International Occasional Symposium of the European Grassland Federation: 1–14.
2. Török, P. and Dengler, J. (2018) Palearctic grasslands in transition:
3. Overarching patterns and future prospects. Grasslands of the world: Diversity, management and Conservation, 15–26. CRC Press.
4. Helm, A. and Toussaint, A. (2020) Assessment of the ecological functioning of semi-natural communities. University of Tartu, Institute of Ecology and Earth Sciences.

Source:

Prangel, E., Kasari‐Toussaint, L., Neuenkamp, L., Noreika, N., Karise, R., Marja, R., Ingerpuu, N., Kupper, T., Keerberg, L. and Oja, E. (2023) Afforestation and abandonment of semi‐natural grasslands lead to biodiversity loss and a decline in ecosystem services and functions. Journal of Applied Ecology 60 (5): 825–836.

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“Science for Environment Policy”: European Commission DG Environment News Alert Service, edited by the Science Communication Unit, The University of the West of England, Bristol.

Notes on content:

The contents and views included in Science for Environment Policy are based on independent, peer reviewed research and do not necessarily reflect the position of the European Commission. Please note that this article is a summary of only one study. Other studies may come to other conclusions.