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NATIONAL (KXAN) – Hate them or love them, spiders play a vital role in our environment. According to the National Institutes of Health, spiders kill an estimated 400-800 tons of prey, mostly insects, each year. They help prevent the spread of deadly diseases carried by mosquitoes and protect our crops from grasshoppers and beetles.
A new study funded by the National Science Foundation and led by scientists with the University of Maryland may have found a way to increase spider populations: tree diversity.
The study, published this summer in the peer reviewed journal Ecology, looked at the impact deforestation is having on predators, like spiders, that handle pest regulation, like insects.
Beginning in 2013, the researchers began planting plots of trees. Some of the plots had one type of tree, while others had a mixture of species. The researchers used 15 different tree species in their experiment.
In 2019, the team looked at how spiders had developed in the trees. They discovered in the plots with a greater diversity of trees, spiders were more abundant than those with single species.
The diverse plots, which had between four and twelve different species, had up to 50% more spiders in them.
Why would we want more spiders?
It always seems to come back to climate change. According to the National Science Foundation, as the world warms, insect population is expected to flourish. This includes insects that transmit diseases like mosquitoes and ticks.
Spiders could help eliminate these pests before they get out of hand.
“The work will provide useful information to forest management practices that take advantage of natural predators.” said Andrea Porras-Alfaro, a program director in NSF’s Division of Environmental Biology in a statement.
Season of the spiders
The researchers also took a look at when spider populations increased. They found that in late summer, the impact of plot diversity doubled. Meaning that if a plot with more diverse trees already had more spiders than the other plot, in late summer there were even more.
Lead author of the paper, Karin Burghardt, told the National Science Foundation that tree “height, canopy cover and foliage density” led to a the higher spider population.
The team also discovered there were more prey in the diverse tree plots.
The team concluded that more diverse tree planting “may better maintain higher trophic levels and ecosystem functions.”