LB 1-4 - Passive monitoring of avian habitat on working lands

Intensive agricultural landscapes are a challenge for wildlife managers, policy makers, andlandowners hoping to increase the diversity of desired wildlife species, such as grassland birds,which require urgent conservation action. In intensive agricultural landscapes, like those of themidwestern USA, most land area is privately owned and operated and managed primarily forproduction. Conducting ecological research in intensive agricultural landscapes thus requirescollaborative approaches aimed at farm owners and operators. Recent advances in acoustic datacollection and high-resolution habitat mapping, including low-cost acoustic recorders andsatellite remote sensing, may be well positioned to address this challenge by enabling expandedassessments and monitoring of wildlife populations and habitats across regions. This studyexamined fine grain habitat characteristics and their relationship with avian biodiversity inintensive agricultural landscapes at 44 agricultural sites across Iowa, USA. Passive acousticmonitoring and manual identification of bird species allowed for measurement of vocalizing birdrichness. High resolution mapping of noncrop vegetation provided detailed information on smallnoncrop vegetation habitat complexes within row-crop agriculture. Measures of image textureprovided characterizations of compositional heterogeneity within noncrop vegetation. Generallinear Poisson modeling demonstrated robust associations between noncrop vegetation andvocalizing bird richness, yet variation in grassland bird richness was not well predicted bynoncrop vegetation. Noncrop vegetation texture demonstrated potential as a predictor ofvocalizing bird richness, though not better than or when combined with noncrop vegetated area,indicating it may not be an independent measure of habitat quality. Passive acoustic monitoringresulted in useful data at 44 out of 60 originally selected sites, with some lost to failed recordersand/or collaboration issues. Challenges remain in detecting habitat characteristics that promotegrassland birds in row crop landscapes. Working toward probabilistic research design acrossprivately owned working landscapes and incorporating more detailed management practiceinformation would improve the transferability of this approach to farmland management andpolicy.