Forest loss escalates biodiversity change
Forest loss does not always lead to a decline in biodiversity but can amplify how it changes. This is one of the results of a recent study from an international team of researchers, including the German Centre for Integrative Biodiversity Research (iDiv) and Martin Luther University Halle-Wittenberg (MLU). Focussing on biodiversity data spanning 150 years and over 6,000 locations, the study, published in the journal Science, reveals that as tree cover is lost across the world’s forests, plants and animals are responding to the transformation of their natural habitats. However, these responses may be delayed by decades.
Forests support around 80% of all species living on land, from eagles and bluebells, to beetles and many more. This biodiversity provides important ecosystem services. And, importantly, some species, such as the rosalia longicorn beetle, survive best in intact old-growth forests. However, forests are being altered by human activities. For example, they are being converted to rangelands for grazing cattle, or to grow agricultural crops.
The researchers, including Dr Shane Blowes of the German Centre for Integrative Biodiversity Research (iDiv) and Martin Luther University Halle-Wittenberg (MLU), investigated the impacts of forest loss on species and biodiversity over time and around the world, revealing that forest loss amplified both gains and losses in the abundance of different species as well as in the overall biodiversity.
Forest loss amplifies both gains and losses in biodiversity
“Biodiversity, the types of species like different plants and animals around the world, is always changing and the species we see on our forest walks today are likely different from the ones we saw growing up,” says lead author Gergana Daskalova of the University of Edinburgh. “Surprisingly, we found that forest loss doesn’t always lead to biodiversity declines. Instead, a loss in forest cover can amplify the ongoing biodiversity change: If a plant or animal species was declining before forest loss, its decline becomes even more severe after forest loss. The same intensification was also true for increasing species.”
This study used the BioTIME and Living Planet biodiversity databases that contain data collected by researchers working at sites around the world. Bringing together over 5 million records of the numbers of different plants and animals with information on both historic and contemporary peaks in forest loss, the researchers analysed the worldwide impacts of forest loss on biodiversity. “To get a global picture of how the planet is changing, different types of information – from observations of plants and animals on the ground through to satellite records of ecosystem change from space – had to be combined,” says Dr Isla Myers-Smith, co-senior author of the University of Edinburgh.
Biodiversity responses may be delayed by decades
The international research team discovered both immediate and delayed effects of forest loss on ecosystems, indicating that biodiversity responses to human impacts are diverse and play out across decades. The pace at which biodiversity responds to forest loss varies from a few years, as is the case for many short-lived grasses, light-loving plants and insects, to decades for long-living trees and larger birds and mammals. For long-lived species, the effects of forest loss do not happen right away and could take decades to become apparent in the biodiversity data that scientists collect.
The findings also reveal that some tropical areas experience more forest loss now than they have ever seen in the past, resulting in declining numbers of different animal species. In North America and Europe, the greatest loss of forests often occurred centuries ago, however even the smaller amounts of forest loss in the present day led to different biodiversity responses, escalating gains in certain species and losses in others.
“Understanding the different ways, both positive and negative, that forest loss influences biodiversity, can improve future conservation and restoration of global ecosystems. And collaborative science that integrates datasets from around the world are important for assessing both the state of the world’s forests, as well as the millions of plants and animals they support,” says Dr Shane Blowes.
Dr Shane Blowes, firstname.lastname@example.org
Gergana N. Daskalova, Isla H. Myers-Smith, Anne D. Bjorkman, Shane A. Blowes,
Sarah R. Supp, Anne E. Magurran, Maria Dornelas (2020). Landscape-scale forest loss as a catalyst of population and biodiversity change. Science, DOI: 10.1126/science.aba1289