Land equivalent to an area half the size of Australia has been abandoned over the past five decades, though policymakers and conservationists have spent little time trying to understand how that impacts biodiversity and how such territory can contribute to the world meeting its targets under the Global Biodiversity Framework (GBF), according to research published this week.

Around 400 million hectares of land globally has been abandoned amid rural depopulation, with almost a third of that in the former Soviet Union, according to an article by researchers at the International Institute for Applied Systems Analysis (IIASA) in Vienna and the University of Goettingen, published in the journal Science.

Most of the area in question is former agricultural land, though there are also abandoned pastures, forestry areas, mines, factories, and entire human settlements, according to the study.

This will have a huge impact on biodiversity in these areas. Left to its own devices, plant and wildlife in some areas might flourish without human intervention, whereas others – especially where low-intensity farming has created ecosystems interdependent of land and people – might face collapse in the absence of human intervention.

For global policymakers and conservationists plotting strategies for how they can meet the 30% land and sea protection targets of the GBF, abandoned land can offer great opportunities, yet little has been done to explore the potential, according to the study.

“[COP15] set new global goals for biodiversity, but land abandonment did not have a prominent place on the agenda and its role in meeting conservation targets remains unexplored,” the study said.

“A global synthesis of the conservation potential of abandoned land is still missing, and there are few systematic reviews and meta-analysis.”

CHOICES

In order to ensure the deserted land plots can contribute to the Montreal targets, planners must understand when land abandonment presents opportunities and when it presents threats, and then make choices, said Gergana Daskalova, a global change ecologist at IIASA’s Biodiversity Ecology and Conservation Research Group and a co-author of the study.

For example, a number of plants, birds, and invertebrates living on grasslands are threatened globally.

Many of those grasslands are maintained via grazing, but when regions get depopulated, livestock numbers drop, and the grassland areas that have sufficient precipitation will over time transform into a forest.

“A challenge then is in determining for which species, which types of ecosystems, and for what type of outcomes we would like to manage a landscape,” Daskalova told Carbon Pulse.

“When it comes to abandoned land, the same reality can be simultaneously a success for forest conservation, a threat for grassland species, an opportunity for rewilding, but also a loss of cultural landscapes and human culture and traditions.”

She said abandoned and depopulating landscapes are prime candidates for hosting projects where conservation can achieve multiple benefits, but that it simply hadn’t been discussed to any serious degree in the run-up to the GBF.

That also includes the temporal perspective, she said.

“Abandoned landscapes are landscapes in transition, so we need to track how the emerging ecosystems develop over time to know – if a given abandoned area joins the protected network of a region or country today, what will that area look like in a decade or a century? Can we just let it be or are interventions needed?”

BEYOND LAND

The IIASA/University of Goettingen study focused on land areas, but the challenge is the same for the other part of the GBF’s 30×30 target – water.

“[400 million hectares is] an immense amount of land and the area would be even bigger if we [included] abandonment beyond terrestrial ecosystems too, for example abandoned fisheries and closed down commercial fish and crustacean farms in both marine and freshwater environments,” Daskalova said.

Also, the geographical locations of the abandoned land areas have played a role in insufficient research into the biodiversity effects of people packing up and heading to ever-growing cities.

“While we know that there is a lot of abandonment, a big unknown is still how much exactly and the global hotspots of abandonment – for example Eastern Europe, Central Africa, and South-East Asia – also all coincide with regions that have been historically underrepresented in science and data collection,” Daskalova told Carbon Pulse.

The study called for biodiversity change on abandoned land to be included in regional and global assessments, policies, and scenarios, and that the reuse of abandoned land should balance economic needs with restoration and conservation goals.

“The management of abandoned land should take a socioecological perspective and consider connections between people and nature,” the study said.

By Stian Reklev – stian@carbon-pulse.com

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