Spacing characteristics between vegetation could be a harbinger of degradation of dryland ecosystems: study

Scientists have discovered that the spatial arrangement of plants in arid areas may be a sign of environmental degradation, according to a new study.

One of the iconic features of drylands is the striking appearance of patches of plants surrounded by bare soil. This spatial structure of arid vegetation has long fascinated scientists, but a new study published in Proceedings of the National Academy of Sciences, shed new light on why these plants group together in this way.

An international team of scientists, including from the University of Birmingham, combined field data from 115 sites around the world and used mathematical models and remote sensing to build a picture of the impact of the environment on the particular structure of plant life.

Dr Juliano Sarmento Cabral, associate professor of biodiversity modeling and environmental change at the University of Birmingham who worked on the study, said: “There are two factors driving the biodiversity crisis that expected to have catastrophic synergies: land use and climate change. We urgently need to understand how ecosystems respond to lower humidity and less available water, given the increase in extreme droughts expected under the looming climate crisis, something the UK already has lived in 2022.

“However, the ability of ecosystems to adequately respond to climate change could be compromised if they already suffer from human-caused degradation, such as overgrazing, biodiversity loss and resource exploitation We are now able to identify telltale signs of resource degradation and exploitation and the ability to cope with a drying environment.

Dr Sarmento Cabral continued: “Self-organizing spatial patterns are a common feature of complex systems, such as microbial communities and mussel beds, and of course dryland vegetation. Researchers have extensively studied the implications of this phenomenon, such as functioning and resilience, but until now there has been little to no empirical evidence to support this reasoning. To fill this gap, we analyzed global drylands along an aridity gradient to see if we could find a link between aridity levels and plant spacing.

Scientists have found that the spatial structure of vegetation increases with aridity, meaning that the drier the environment, the farther apart plant life is.

Healthy dryland ecosystems adjust their spatial structure to better cope with stressful environmental conditions, such as drought or high temperatures. As a result, these self-organizing vegetation patterns give drylands the ability to adapt to these changing conditions while maintaining their functioning, making them more resilient.

However, researchers have also found that this adaptive capacity is lost when ecosystems are already degraded.

Dr Sarmento Cabral added: “Our study showed that the spatial structure of vegetation plays a critical role in the resilience of arid ecosystems. We also found that degraded ecosystems cannot adapt their spatial structure and, as a result, they become even more prone to further disturbance. degradation as aridity and water shortages increase.

Scientists suggest that monitoring changes, or lack of changes, in the spatial structure of plants could be used as an early indicator of ecosystem degradation. This could be a crucial step in developing tools to manage and preserve dryland ecosystems in a hotter, drier world.

Additionally, because vegetation pattern is also critical in other natural systems, such as microbial communities or coastal wetlands, the study results could also have implications for systems other than areas arid.

Dr Sarmento Cabral concluded: “As the climate crisis continues and its results are increasingly felt, it is essential that we find ways to closely monitor ecosystems at risk. Drylands are home to some of our rare, endangered wildlife and plants. we must be able to detect the early signs of dryland suffering so that we can take action to correct and protect what we have left. »