Scientists Collaborate to Bring Insectivorous Bats into the Vineyard
Echolocation recording system attached to a vine post at one of our tree sites.
What Has ANR Done?A collaborative study by UC and US Forest Service, Pacific Southwest Research Station, scientists is examining the habitat value to insectivorous bats of the remnant valley oak tree within the vineyard. Fourteen cooperating grape growers in San Luis Obispo County are helping scientists answer this question. In each of the vineyards, we set up bat echolocation-call recorders, one at the tree and one 100 meters from the tree within the open vineyard. At the tree and the no-tree sites, we also erected an insect trap to assess insect abundance.
Research demonstrates that the iconic valley oak brings insect-eating bats into the vineyardWe recorded 11 species of insectivorous bats within the vineyards. Over 2.5 times more of the bat calls were recorded at the trees than in open vineyard. Of the recordings, a group of bats adapted specifically to treed habitat (woodland bats or edge-adapted bats) was recorded nearly 11 times more at trees than in the open vineyard. Indeed, over 90% of this group’s echolocations were at trees. Our data indicate that a large oak tree attracts insectivorous bats to the interior of a vineyard. Importantly, the trees attracted a group of woodland or edge-adapted bats to the interior of the vineyard that would not have been within the vineyard if not for the tree. Similar numbers of insects were trapped at the trees and in the open vineyard, suggesting that in addition to insect foods, other habitat features of the oak tree are important to the bats. For example, the bats could be attracted to the trees for preferred insect foods, protection from predators, improved foraging conditions, and for roosting. Further research is warranted to answer these questions, and whether a tree that provides bat habitat could also help growers keep populations of night-time insect pests in check and potentially reduce the use of chemical pesticides.
Supporting Unit:San Luis Obispo County
Bill Tietje, Wildlife Extension Specialist, Department of Environmental Science, Policy, and Management (ESPM), UC Berkeley firstname.lastname@example.org; Anne Polyakov, Data Analyst, ESPM UC Berkeley; Ted Weller, Ecologist, US Forest Service, Pacific Southwest Research Station email@example.com