In one of the first studies of its kind, the researchers pointed out that the ability of animal-dispersed plants to keep pace with climate change has been reduced by 60 per cent due to the loss of mammals and birds that help such plants adapt to environmental change.
The National Science Foundation funded the study that was published in Science. The researchers at Rice University, the University of Maryland, lowa State University and Aarhus University in Denmark used machine learning and data from thousands of field studies to map the contributions of seed-dispersing birds and mammals Worldwide. They compared maps of seed dispersal today with maps showing what dispersal would look like without human-caused extinctions or species range restrictions to understand the severity of the declines.
Rice University ecologist Evan Fricke, the study’s first author said that some plants live hundreds of years, and their only chance is during the short period when the seed move across the landscape. With climate change, several plant species must move to a more suitable environment and they depend on seed dispersers. The plants can face extinction if there are too few animals to move their seeds far enough to keep pace with changing conditions. “If there are no animals available to eat their fruits or carry away their nuts, animal-dispersed plants aren’t moving very far,” Fricke said.
Many plants people depend on, both economically and ecologically, rely on seed-dispersing birds and mammals. Fricke said the study is the first to quantify the scale of the seed-dispersal problem globally and identify the regions most affected. The authors used data synthesized from field studies around the world to train a machine-learning model for seed dispersal and then used the model to estimate the loss of dispersal caused by animal declines. “In addition to the wake-up call that declines in animal species have vastly limited the ability of plants to adapt to climate change this study demonstrates the power of complex analyses applied to publicly available data,” said Doug Levey, a program director in NSFs Division of Environmental Biology