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Landscape monitoring reveals initial trends in occupancy and activity of bats in multiple‐use forests
Author(s) -
Law Bradley,
Gonsalves Leroy,
McConville Anna,
Tap Patrick
Publication year - 2021
Publication title -
austral ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.688
H-Index - 87
eISSN - 1442-9993
pISSN - 1442-9985
DOI - 10.1111/aec.12976
Subject(s) - occupancy , threatened species , biodiversity , ecology , geography , woodland , habitat , disturbance (geology) , abundance (ecology) , taxon , insectivore , biology , paleontology
Abstract Biodiversity monitoring is recognised as a key action for ecologically sustainable land use, but there are few examples of landscape programmes. We outline the first five years of biodiversity monitoring focusing on insectivorous bats in low rainfall, multiple‐use forests and woodlands of the Pilliga, Australia. Using ultrasonic sampling over multiple nights, both on‐ and off‐tracks, we identify annual trends in bat activity and occupancy and environmental covariates. Trends differed depending on whether occupancy or bat activity was the response variable. Site occupancy was almost 100% and remained stable and/or did not decline for most species nor diversity over the monitoring period, suggesting little variation in bat populations. In comparison, total activity was initially very high (567 passes night −1 on‐track) and then declined by up to 40% in the following three years, but then fully recovered in the fifth year. This general pattern was evident both on‐ and off‐tracks for most taxa, though activity was three times greater on‐ than off‐track, highlighting the importance of these distinct habitat features for bats. Multivariate state‐space (MARSS) models predicted, unexpectedly, that high winter rainfall prior to our surveys was negatively related to activity for many taxa. In contrast, disturbance from timber harvesting or fire had weak or no identifiable effects on trends in activity for most taxa. One exception was Chalinolobus picatus (threatened), whose occupancy off‐tracks was negatively related to the extent of recent (<5 years) fire and to harvesting, though at the landscape scale, occupancy remained stable. This result, together with patterns for other bat taxa, suggests that disturbance effects were short‐lived/dispersed and/or environmental mitigations were effective at maintaining bat populations at a landscape level. Annual monitoring highlighted annual variation in activity and its implications when setting a baseline for monitoring. We also discuss modifications to future monitoring effort, based on the existing five years of data.