Department of Agriculture / Department of the Interior

Forest Service / Bureau of Land Management

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Interagency - Pacific Northwest

Oregon - Washington State

great view

Interagency Special Status /
Sensitive Species Program (ISSSSP)

Species Index - Fauna / Mammals / Bats

Bat Grid Monitoring – Oregon and Washington


Study Summary

The study objective was to map species-specific baselines within Oregon and Washington of predicted occurrence probabilities, accounting for imperfect detection and annual turnover, against which future declines can be evaluated, models updated, and trends communicated through maps. These maps reflect an 8-year (2003-2010) monitoring effort from the Bat Grid Program.  The dataset used for modeling was a subset of Bat Grid data using capture and acoustic survey results from 241 of the 4500 total number of 10 km x 10 km  sample units (grid cells) across Oregon and Washington, USA.

Maps were produced from modeled predictions of probability of occurrence with Bayesian occupancy models using a subset of Bat Grid data that met specific  criteria for modeling, including, for example, only records where data collection occurred between 1 June and 15 September, on nights where capture and recording efforts lasted ≥ 2 hours, etc... in order to ensure data integrity and model assumptions. Prediction error or uncertainty, the standard deviation of predicted probabilities (in Bayesian lingo, the std. dev. of the posterior probabilities), are mapped as well as the predictions themselves. We included 6 covariates in models as explanatory predictor variables: % cover of forest, % cover of cliffs and canyons, avg. snags/hectare, avg. elevation, std. dev. of elevation, avg. annual precipitation, all summarized per 10 km x 10 km Bat Grid sample unit. These maps are also available for download. We produced maps for 11 of the 14 species for which we built models. Antrozous pallidus, Corynorhinus townsendii, and Euderma maculatum were not well represented in the dataset (infrequently captured and recorded) and were not mapped, but models were developed and useful information on these species can be found in Rodhouse, Ormsbee, Irvine, and others (In press).

Manuscripts and Survey Protocol

Geographic Information System (GIS) files

Maps - Environmental Covariates Used in Models (All with Surveyed Units)

Maps - Species-specific

Eptesicus fuscus, Big-brown bat

Lasiurus cinereus, Hoary bat

Lasionycteris noctivagans, Silver-haired bat

Myotis californicus, California myotis

Myotis ciliolabrum, Small-footed myotis

Myotis evotis, Long-eared bat

Myotis lucifugus, Little brown bat

Myotis thysanodes, Fringed myotis

Myotis volans, Long-legged myotis

Myotis yumanensis, Yuma myotis

Parastrellus hesperus, Canyon bat