Bats!

October is Bat Appreciation Month, and with the celebration of Halloween this week I thought I’d take a moment to share with you some of the awesome things I learned about bats while earning my degree at UCSC. For my senior thesis I worked in collaboration with a PhD student to examine the effects of agricultural intensification on bat species communities, and wanted to share with you some reasons why bats are so important in agroecosystems and how the farmers here at High Ground are doing their part to support these important creatures.

Bats eat pests! There are many common Halloween images of bats as spooky blood-sucking vampires, but in reality the bats that live here on California’s central coast mostly eat insects. A large proportion of the insects that bats eat are in the families of moths, grasshoppers, and beetles, many of which are big-time crop pests. A single bat can eat up to its weight in insect prey in a single night of foraging, which makes these little guys incredibly important for insect pest control on organic farms like ours. In fact, studies have shown that bats may be even more important than birds for controlling insect pests.

Did you know that we have thirteen different species of bats in our area? Different species have adapted in different ways to be able to exploit the natural variation in the landscapes of the central coast. There are open-area bat species that are bigger in size and have long wings that make them fast flyers that can go long distances over open fields. These bats use low, long echolocation calls to be able to “see” long distances. Conversely, there are forest-dwelling bat species that are smaller in size and have short, stubby wings. These short wings allow forest bats to fly more slowly and give them more maneuverability, so they can fly in habitats that are cluttered with trees and other vegetation. Forest bats use short, high-pitched echolocation calls which make it so they can “see” really well close up and fly super close to vegetation in cluttered habitats. However, these high-pitched calls don’t travel very far across open fields, so forest bats have to stick near the trees to be able to “see.” Open-area and forest-dwelling bats eat different kinds of insects, so it’s important to have a balanced community of both types of bat species in order to have the most protection against insect pest outbreaks.

Large-scale industrial agriculture is really harmful to bats. Many of the native plants that grew in central California have been removed to make room for industrial agriculture, and the crops that are planted in their place have very little diversity. These big open fields are virtually impossible for many of the forest-dwelling bat species to cross, and the populations of forest bats are suffering because of this major habitat transformation. Even the open-area bats which can exploit these huge fields are suffering because of the land management practices used by industrial agriculture. The use of agricultural chemicals like pesticides and synthetic fertilizers leaves a lot of chemical residue in nearby bodies of water, which can make bats sick. When bats eat insects that have been sprayed by pesticides, the pesticides collect in their bodies and poison the bats and their young.

At High Ground Organics, we are dedicated to farming in a way that works with the natural ecosystem, not against it. Growing a diverse array of vegetables not only keeps our CSA members happy, it makes the bats happy, too! In addition to the vegetable crops that are rotated throughout our fields, our farm has hedgerows made up of large, perennial plants that provide year-round habitat for bats and other animals. The hedgerows help forest-dwelling bats navigate through our fields, and protect all kinds of bats from wind, rain, and overhead predators like owls. We don’t use synthetic fertilizers or pesticides, and instead rely on working with nature’s natural balance to keep pest populations under control.  By farming organically and providing non-crop perennial vegetation on our farm, we are supporting a balanced and diverse community of bat species. They might be hard to spot, but the bats on our farm are an important part of our farm ecosystem. So, here’s to bats, appreciated at High Ground during October as well as the rest of the year.

*Photo: A Myotis yumanensis hunting a moth. Photo credit: Michael Durham