Rotoaira Forest Re-surveyed for Bats

04 February 2012
In early 2012 Rotoaira Forest was re-surveyed to determine the presence and distribution of both long-tail and short-tail bats.

Bat Survey 2012 - Rotoaira Forest

The Executive Summary from the recently completed survey of Rotoaira Forest by Enviro Research Ltd is shown below.

"A survey aimed at determining the presence and distribution of native bat species in Rotoaira Forest was undertaken in summer 2003 (Beath; 2003a). Short-tail bats (Mystacina tuberculata rhyacobia) were found at 11% of sites and long-tail bats (Chalinolobus tuberculata) were found at 82% of sites.

A repeat survey at the same sites in summer 2012 recorded short-tail bat presence at 42% of sites and long-tail bat presence at 73% of sites. Both surveys utilised Automatic Bat Monitors (ABMs). Advances in technology meant that the 2012 survey used more efficient machines that sample both species simultaneously with greater accuracy and this contributed to the increase in distribution of short-tail bats.

The repeat survey in 2012 aimed to determine whether harvest and road creation had affected distribution and relative activity levels, particularly of long-tail bats. Activity levels of bats in Rotoaira forest are low by comparison to other studies in similar habitats within New Zealand. However, activity levels of long-tail bats had increased by >200% at five sites in 2012, showing considerable variation between sites and years, indicating that harvest had affected activity levels both positively and negatively. Additionally, recent pest control operations may have contributed to higher long-tail bat activity levels at some sites.

Overall, the mean rate of activity in long-tail bats had decreased by 30.3% in 2012, suggesting a trend of decline, but the change was not significant (Fishers exact test, P = 1.000). In order to elucidate the cause of such variation, particularly between sites, greater survey effort at significantly more sites for significantly longer periods of time would be required."