Habitat Selection by Bats in Fragmented and Unfragmented Aspen Mixedwood Stands of Different Ages

To determine if bats prefer certain ages of aspen mixedwood forest for roosting and foraging, and to predict the impacts of logging on bats, we compared the relative abundances and foraging activities of bats in young, mature, and old stands in  and , using bat detectors. In , we also assessed post-logging bat abundances in two of the mature and two of the old stands. We tracked radio-tagged Myotis lucifugus and Lasionycteris noctivagans to roost trees, which we measured and compared to a random sample of wildlife trees. Mean total activity of all bats was significantly greater in old than in young or mature stands. It also appeared greater in unfragmented than fragmented stands, but not significantly so. All  roost trees were in old forests. Bats preferred tall (mean: . m), newly dead Populus spp. with heart rot and low leaf cover (mean: %). Tree-roosting colonies were small (– bats) and transient. Bats likely select trees large enough to house colonies and provide suitable temperatures, and these trees are only available in old stands. Roost preference likely explains observed activity patterns. To sustain bat populations in these forests, old stands must be retained and roost sites preserved by managing the forest at the stand level.

[1]  S. Lewis.  Roost Fidelity of Bats: A Review , 1995 .

[2]  R. Brigham,et al.  Intraspecific variation in wing loading affects habitat use by little brown bats (Myotis lucifugus) , 1995 .

[3]  M. Fenton,et al.  Raptors and bats: threats and opportunities , 1994, Animal Behaviour.

[4]  M. Brock Fenton,et al.  The foraging behaviour and ecology of animal-eating bats , 1990 .

[5]  T. Spies,et al.  Vegetation Responses to Edge Environments in Old-Growth Douglas-Fir Forests. , 1992, Ecological applications : a publication of the Ecological Society of America.

[6]  I. Newton.  The role of nest sites in limiting the numbers of hole-nesting birds: A review , 1994 .

[7]  Alan B. Berg,et al.  Snag Characteristics and Dynamics in Douglas-Fir Forests, Western Oregon , 1980 .

[8]  R. W. Mannan,et al.  Management and conservation of old-growth forests in the United States , 1988 .

[9]  J. Stelfox.  Relationships Between Stand Age, Stand Structure, and Biodiversity in Aspen Mixedwood Forests in Alberta , 1995 .

[10]  R. Barclay.  Population structure of temperate zone insectivorous bats in relation to foraging behaviour and energy demand , 1991 .

[11]  R. D. Ohmart,et al.  The Effects of Timber Harvesting on Breeding Birds in a Mixed-Coniferous Forest , 1978 .

[12]  H. Aldridge,et al.  Variation in Habitat Use and Prey Selection by Yuma Bats, Myotis yumanensis , 1992 .

[13]  S. Lewis.  Effect of climatic variation on reproduction by pallid bats (Antrozous pallidus) , 1993 .

[14]  M. Fenton,et al.  Habitat use by foraging insectivorous bats , 1987 .

[15]  J. M. Perkins,et al.  Differential Use of Some Coniferous Forest Habitats by Hoary and Silver-Haired Bats in Oregon , 1988 .

[16]  H. Aldridge,et al.  Morphology echolocation and resource partitioning in insectivorous bats , 1987 .

[17]  T. J. Breen,et al.  Biostatistical Analysis (2nd ed.). , 1986 .

[18]  R. Barclay,et al.  Ecomorphology of Insectivorous Bats: A Test of Predictions Using Two Morphologically Similar Species , 1992 .

[19]  F. H. J. Crome,et al.  Bats and Gaps: Microchiropteran Community Structure in a Queensland Rain Forest , 1988 .

[20]  R. Barclay.  Long- versus short-range foraging strategies of hoary (Lasiurus cinereus) and silver-haired (Lasionycteris noctivagans) bats and the consequences for prey selection , 1985 .

[21]  C. Tidemann,et al.  Factors Affecting Choice of Diurnal Roost Site by Tree-Hole Bats (Microchiroptera) in Southeastern Australia , 1987 .

[22]  R. E. Noble,et al.  Nest-Box and Natural-Cavity Use in Three Mid-South Forest Habitats , 1981 .

[23]  H. Andrén,et al.  Effects of habitat fragmentation on birds and mammals in landscapes with different proportions of suitable habitat: a review , 1994 .

[24]  Stephen R. Humphrey,et al.  Summer Habitat and Ecology of the Endangered Indiana Bat, Myotis sodalis , 1977 .

[25]  L. Wauters,et al.  Space use and dispersal of red squirrels in fragmented habitats , 1994 .

[26]  D. K. Rosenberg,et al.  Use and Characteristics of Snags in Young and Old Forest Stands in Southwest Virginia , 1988, Forest Science.

[27]  J. Rayner,et al.  Ecological Morphology and Flight in Bats (Mammalia; Chiroptera): Wing Adaptations, Flight Performance, Foraging Strategy and Echolocation , 1987 .

[28]  M. Fenton,et al.  Echolocation and feeding behaviour in four species of Myotis (Chiroptera) , 1979 .

[29]  R. W. Mannan,et al.  Use of Snags by Birds in Douglas-Fir Forests, Western Oregon , 1980 .

[30]  M. Fenton,et al.  A comparison of foraging by Eptesicus fuscus (Chiroptera: Vespertilionidae) in urban and rural environments , 1985 .

[31]  A. Estrada,et al.  Bat species richness and abundance in tropical rain forest fragments and in agricultural habitats at Los Tuxtlas, Mexico , 1993 .

[32]  B. McNab.  Evolutionary Alternatives in the Physiological Ecology of Bats , 1982 .

[33]  Rj Taylor,et al.  Use of roost sites by four species of bats in state forest in south-eastern Tasmania , 1988 .

[34]  Michael H. Kutner.  Applied Linear Statistical Models , 1974 .

[35]  Bruce C. Larson,et al.  Forest Stand Dynamics , 1990 .

[36]  R. Brigham.  Flexibility in foraging and roosting behaviour by the big brown bat (Eptesicus fuscus) , 1991 .

[37]  D. J. Hall,et al.  An Experimental Test of the Effects of Predation Risk on Habitat Use in Fish , 1983 .