3.2.5 Habitat Standards

A minimum amount of habitat data must be collected for each survey type. The type and amount of data collected will depend on the scale of the survey, the nature of the focal species, and the objectives of the inventory. As most provincial-funded wildlife inventory projects deal with terrestrial-based wildlife, the terrestrial Ecosystem Field Form developed jointly by MOF and MELP (1995) should be used. However, under certain circumstances, this may be inappropriate and other RIC-approved standards for ecosystem description may be used. For a generic but useful description of approaches to habitat data collection in association with wildlife inventory, consult the introductory manual, Species Inventory Fundamentals (No. 1).

Accompanying data forms provide guidance as to standard description of roosts, whether located in cliff, caves, trees, or buildings.

3.2.6 Survey Design Hierarchy

Bat surveys follow a survey design hierarchy which is structured similarly to all RIC standards for species inventory. Figure 3 clarifies certain terminology used within this manual (also found in the glossary), and illustrates the appropriate conceptual framework for detection and capture surveys for bats. A survey set up following this design will lend itself well to standard methods and RIC data forms.

Figure 3. RIC species inventory survey design hierarchy with examples.

3.2.7 Combining Techniques to Survey Bats

Because no one technique can adequately sample all bat species present in British Columbia, it is recommended that several techniques be used in combination to obtain presence/not detected and relative abundance data (Table 2). The same general techniques are used to assess both these levels of intensity , and therefore data on species presence and their relative levels of activity can be collected at the same time. Relative abundance of a bat species can be compared between areas or over time, but reliable comparisons between species are not possible, because species differ in their degree of catchability or detectability. Absolute abundance estimates are not possible, except at specific roosts.

In British Columbia, mist nets, harp traps, ultrasonic bat detectors, and listening for E. maculatum should all be employed to determine presence/not detected and relative abundance of bats, as these methods tend to complement one another. The species that tend to be under-estimated or missed by one method are often sampled by one of the other methods. For example, the presence of certain species (e.g., M. keenii) may be difficult to determine given their indistinct morphology, low vulnerability to trapping, and/or limited species identification ability based on the current resolution of bat detectors. With two to three workers, it is quite easy to employ all four methods simultaneously in a study area. However, the emphasis on specific survey methods employed may vary for different survey intensities (Table 2, 3) and/or the target species under examination (Table 4).

Table 2. Recommended combinations of techniques to assess presence/not detected, relative abundance, and absolute abundance of bats.

Objective	Recommended Combination of Techniques
Presence/Not Detected	Capture Techniques (Mist netting; harp trapping) used simultaneously with Ultrasonic Detection and Listening for E. maculatum.
Relative Abundance	Capture Techniques (Mist netting; harp trapping) used simultaneously with Ultrasonic Detection and Listening for E. maculatum.
Absolute Abundance	Roost counts (emergence or surface area); possibly in conjunction with telemetry (to locate roost).

Table 3. Types of inventory surveys, the data forms needed, and the level of intensity of the survey.

Survey Method	Forms Required	*Intensity
Mist Netting / Harp Trapping	Wildlife Inventory Project Description Form Wildlife Inventory Survey Description Form - General Animal Observations Form - Bat Capture: Mist Netting / Harp Trapping Taxonomic Code Form - Bats Ecosystem Form	PN
Bat Detection	Wildlife Inventory Project Description Form Wildlife Inventory Survey Description Form - General Animal Observations Form - Bat Detection Taxonomic Code Form - Bats Ecosystem Form	PN RA
Roost Count	Wildlife Inventory Project Description Form Wildlife Inventory Survey Description Form - General Animal Observations Form- Bats Roost Count Ecosystem Form	PN RA
Any Survey Type	Wildlife Inventory Survey Collection Label - is used whenever a voucher specimen is collected.	PN RA

* PN = presence/not detected; RA = relative abundance; AA = absolute abundance

Table 4. Recommended sampling methods for B.C. bats and location of summer roosts (roost information from Holroyd et al., 1994; Nagorsen and Brigham, 1993).

Species	Summer Roost	Recommended Sampling Method
Spotted Bat (Euderma maculatum)	Cliffs	Listen with unaided ear
Townsend's Big-eared Bat (Plecotus townsendii)	Caves, Mines, Buildings	Mist net/Harp trap
Pallid Bat (Antrozous pallidus)	Rock Crevices, Foliage	Mist net at ground level
Big Brown Bat (Eptesicus fuscus)	Buildings, Tree Cavities, Rock Crevices	Mist net (5-10m high) / Bat Detector
Western Red Bat (Lasiurus blossevilli)	Foliage	Bat Detector
Hoary Bat (L. cinereus)	Foliage	Bat Detector
Silver-haired Bat (Lasionycteris noctivagans)	Tree Cavities	Mist net/Harp trap; Bat Detector
California Myotis (Myotis californicus)	Buildings, Tree Cavities, Rock Crevices	Mist net(1-3 m high) / Harp trap
Western Small-footed Myotis (M. ciliolabrum)	Rock Crevices	Mist net(1-3 m high) / Harp trap
Western Long-eared Myotis (M. evotis)	Rock Crevices, Tree Cavities, Buildings	Mist net / Harp trap (roads & cut lines through trees)
Keen's Long-eared Myotis (M. keenii)	Rock Crevices	Mist net/Harp trap
Northern Long-eared Myotis (M. septentrionalis)	Tree Cavities	Mist net / Harp trap (roads & cut lines through trees)
Little Brown Myotis (M. lucifugus)	Buildings, Tree Cavities, Rock Crevices	Mist net (over water at water level) / Harp trap
Fringed Myotis (M. thysanodes)	Buildings, Caves, Rock Crevices	Mist net / Harp trap
Long-legged Myotis (M. volans)	Rock Crevices, Tree Cavities	Mist net / Harp trap
Yuma Myotis (M. yumanensis)	Buildings, Tree Cavities	Mist net (over water at water level) / Harp trap