Even a fire won’t keep a good ant down, according to research at the Robert J. Bernard Biological Field Station on the effects of fire on ants —but which plants grow back after fire and drought do affect ant communities.
For her senior thesis, Tessa Adams ’16 was interested in determining if the ant community changed as a result of the September 2013 brush fire that charred 17 acres at the field station and The Claremont Colleges North Campus Properties. Expectations were that the effects of fire would be significant, but it turns out ants are a hardy, fireproof lot. Results show that there was minimal immediate and no lasting impact on the species by the fire, says Pomona College Professor of Biology Wallace Meyer, director of Bernard Field Station (BFS), a preserve maintained by The Claremont Colleges that protects the rare native ecosystem of California sage scrub.
“It seems like ant assemblages can withstand a fire and it makes sense, they are this super-organism… Fast-moving hot fires affect the surface, meanwhile the ants are down below,” says Meyer. Plus, “fire is a natural component of the ecosystem.”
However, Meyer says, following a fire, areas of land can potentially convert from native flora—in the case of BFS, California sage scrub — to non-native grasslands, which do affect whether ants return. (Rest assured, 22 species of ants are still making their home at BFS.) Drought, too, affects whether sage scrub or non-native grasses grow back and which species of ants make their home in each type of habitat, suggesting that drought — while not as dramatic visually or sense-wise — “is a larger stressor than a fire,” says Meyer.
Meyer says this research is significant because the effects of fire on anything other than plants and mammals are largely unknown. It is important to know these effects for conservation and management of biodiversity since fire is going to become more common, especially in light of global climate change. Adams’ research findings will be used in conservation management plans not only at BFS, but by managers throughout Southern California.
Among the implications for conservation management? One, as long as native plant communities recover after a fire, no action is required, says Meyer. Two, which types of plants grow back favors certain ant species. Three, effects of extreme drought correlated with climate changes are real and felt, making long-term management difficult.
Thanks to her high school AP Environmental Science class, Adams says she came to Pomona knowing she wanted to do ecology research. She says when she stepped foot into BFS, she was awestruck by the California sage scrub habitat.
Adams’ awe quickly turned into action. Adams started working on arthropod research at BFS as a volunteer her first year at Pomona and continued through the years, setting up research sites, collecting pitfall traps, sorting specimens that were collected —and she started seeing a wide range of arthropods at the station.
“After taking Professor Meyer’s Fire Ecology in Southern California class last spring, I became interested in how fire can shape an ecosystem, and I realized that there is little research on the effect of fire on arthropods. I decided to focus my thesis on the effect of fire on ants because the lifestyle of ants, which live in colonies, has the potential to be greatly affected by fire,” says Adams.
She conducted her research by pitfall trapping. She buried a test tube in the ground, with the lip of it level with the surface of the ground. The tube was filled about halfway with a preservation solution — either ethanol or propylene glycol. As the insects run along the ground, they fall into the trap, and the collected specimens serve as a survey of the insects present in an area.
But why choose ants?
“Ants act as decomposers and consume organic waste, such as dead insects. They also serve as a food source for other organisms, such as reptiles, and provide pest control, by eating non-desirable insects like termites. By building their nests, ants aerate the soil and allow water and oxygen to reach the roots of plants. One of the most important roles ants play is in seed dispersal, which is essential for the spread of many plant species,” she says.
Adams points to the creatures as providing crucial ecosystem services that make them important to study because of their broad impact on other organisms and in order to determine ways to conserve the environment they inhabit.
So in other words, remember the old proverb: Go to the ant…consider her ways.