Limits...
Seeing the Forest through the Trees: Considering Roost-Site Selection at Multiple Spatial Scales.

Jachowski DS, Rota CT, Dobony CA, Ford WM, Edwards JW - PLoS ONE (2016)

Bottom Line: At the landscape scale, bat roost-site selection was positively associated with northern mixed forest, increased slope, and greater distance from human development.At the stand scale, we observed subtle differences in roost site selection based on sex and season, but roost selection was generally positively associated with larger stands with a higher basal area, larger tree diameter, and a greater sugar maple (Acer saccharum) component.Collectively, our results highlight the importance of considering day roost needs simultaneously across multiple spatial scales.

View Article: PubMed Central - PubMed

Affiliation: Department of Forestry and Environmental Conservation, Clemson University, 258 Lehotsky Hall, Clemson, South Carolina, 29634-0310, United States of America.

ABSTRACT
Conservation of bat species is one of the most daunting wildlife conservation challenges in North America, requiring detailed knowledge about their ecology to guide conservation efforts. Outside of the hibernating season, bats in temperate forest environments spend their diurnal time in day-roosts. In addition to simple shelter, summer roost availability is as critical as maternity sites and maintaining social group contact. To date, a major focus of bat conservation has concentrated on conserving individual roost sites, with comparatively less focus on the role that broader habitat conditions contribute towards roost-site selection. We evaluated roost-site selection by a northern population of federally-endangered Indiana bats (Myotis sodalis) at Fort Drum Military Installation in New York, USA at three different spatial scales: landscape, forest stand, and individual tree level. During 2007-2011, we radiotracked 33 Indiana bats (10 males, 23 females) and located 348 roosting events in 116 unique roost trees. At the landscape scale, bat roost-site selection was positively associated with northern mixed forest, increased slope, and greater distance from human development. At the stand scale, we observed subtle differences in roost site selection based on sex and season, but roost selection was generally positively associated with larger stands with a higher basal area, larger tree diameter, and a greater sugar maple (Acer saccharum) component. We observed no distinct trends of roosts being near high-quality foraging areas of water and forest edges. At the tree scale, roosts were typically in American elm (Ulmus americana) or sugar maple of large diameter (>30 cm) of moderate decay with loose bark. Collectively, our results highlight the importance of considering day roost needs simultaneously across multiple spatial scales. Size and decay class of individual roosts are key ecological attributes for the Indiana bat, however, larger-scale stand structural components that are products of past and current land use interacting with environmental aspects such as landform also are important factors influencing roost-tree selection patterns.

Show MeSH

Related in: MedlinePlus

Predicted probability of selecting a roost as a function of stand size for male and female Indiana bats (Myotis sodalis) in summer and fall months in Fort Drum, NY, USA between 2007–2011.Solid lines indicate mean posterior probability of use and gray ribbons represent the limits of 95% credible intervals. Each panel assumes bats are faced with a choice of 2 potential roosts: one fixed at the observed mean stand size (vertical dashed line) and the other represented by the value of the x-axis. All other variables are assumed constant.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4814100&req=5

pone.0150011.g003: Predicted probability of selecting a roost as a function of stand size for male and female Indiana bats (Myotis sodalis) in summer and fall months in Fort Drum, NY, USA between 2007–2011.Solid lines indicate mean posterior probability of use and gray ribbons represent the limits of 95% credible intervals. Each panel assumes bats are faced with a choice of 2 potential roosts: one fixed at the observed mean stand size (vertical dashed line) and the other represented by the value of the x-axis. All other variables are assumed constant.

Mentions: The top-ranked stand-level model suggested individual-level slope coefficients varied by sex, season, and their interaction (Table 3). We found evidence that both males and females selected roosts in stands of greater total area in the summer months, but that only males selected these larger stands in the fall months (Fig 3). We also found evidence that both males and females selected roosts within stands with high sugar maple importance value in the fall months, but that only females selected roosts within stands with high sugar maple importance value in the summer months (Fig 4). There was enough variation in individual-level slope coefficients among sexes and seasons that there was no discernable population-level influence from basal area; average tree diameter; American elm, hickory (Carya spp) or Populus spp. importance value; and predicted foraging value (i.e., 95% credible intervals of all elements of θl overlapped 0 for each of these variables).


Seeing the Forest through the Trees: Considering Roost-Site Selection at Multiple Spatial Scales.

Jachowski DS, Rota CT, Dobony CA, Ford WM, Edwards JW - PLoS ONE (2016)

Predicted probability of selecting a roost as a function of stand size for male and female Indiana bats (Myotis sodalis) in summer and fall months in Fort Drum, NY, USA between 2007–2011.Solid lines indicate mean posterior probability of use and gray ribbons represent the limits of 95% credible intervals. Each panel assumes bats are faced with a choice of 2 potential roosts: one fixed at the observed mean stand size (vertical dashed line) and the other represented by the value of the x-axis. All other variables are assumed constant.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4814100&req=5

pone.0150011.g003: Predicted probability of selecting a roost as a function of stand size for male and female Indiana bats (Myotis sodalis) in summer and fall months in Fort Drum, NY, USA between 2007–2011.Solid lines indicate mean posterior probability of use and gray ribbons represent the limits of 95% credible intervals. Each panel assumes bats are faced with a choice of 2 potential roosts: one fixed at the observed mean stand size (vertical dashed line) and the other represented by the value of the x-axis. All other variables are assumed constant.
Mentions: The top-ranked stand-level model suggested individual-level slope coefficients varied by sex, season, and their interaction (Table 3). We found evidence that both males and females selected roosts in stands of greater total area in the summer months, but that only males selected these larger stands in the fall months (Fig 3). We also found evidence that both males and females selected roosts within stands with high sugar maple importance value in the fall months, but that only females selected roosts within stands with high sugar maple importance value in the summer months (Fig 4). There was enough variation in individual-level slope coefficients among sexes and seasons that there was no discernable population-level influence from basal area; average tree diameter; American elm, hickory (Carya spp) or Populus spp. importance value; and predicted foraging value (i.e., 95% credible intervals of all elements of θl overlapped 0 for each of these variables).

Bottom Line: At the landscape scale, bat roost-site selection was positively associated with northern mixed forest, increased slope, and greater distance from human development.At the stand scale, we observed subtle differences in roost site selection based on sex and season, but roost selection was generally positively associated with larger stands with a higher basal area, larger tree diameter, and a greater sugar maple (Acer saccharum) component.Collectively, our results highlight the importance of considering day roost needs simultaneously across multiple spatial scales.

View Article: PubMed Central - PubMed

Affiliation: Department of Forestry and Environmental Conservation, Clemson University, 258 Lehotsky Hall, Clemson, South Carolina, 29634-0310, United States of America.

ABSTRACT
Conservation of bat species is one of the most daunting wildlife conservation challenges in North America, requiring detailed knowledge about their ecology to guide conservation efforts. Outside of the hibernating season, bats in temperate forest environments spend their diurnal time in day-roosts. In addition to simple shelter, summer roost availability is as critical as maternity sites and maintaining social group contact. To date, a major focus of bat conservation has concentrated on conserving individual roost sites, with comparatively less focus on the role that broader habitat conditions contribute towards roost-site selection. We evaluated roost-site selection by a northern population of federally-endangered Indiana bats (Myotis sodalis) at Fort Drum Military Installation in New York, USA at three different spatial scales: landscape, forest stand, and individual tree level. During 2007-2011, we radiotracked 33 Indiana bats (10 males, 23 females) and located 348 roosting events in 116 unique roost trees. At the landscape scale, bat roost-site selection was positively associated with northern mixed forest, increased slope, and greater distance from human development. At the stand scale, we observed subtle differences in roost site selection based on sex and season, but roost selection was generally positively associated with larger stands with a higher basal area, larger tree diameter, and a greater sugar maple (Acer saccharum) component. We observed no distinct trends of roosts being near high-quality foraging areas of water and forest edges. At the tree scale, roosts were typically in American elm (Ulmus americana) or sugar maple of large diameter (>30 cm) of moderate decay with loose bark. Collectively, our results highlight the importance of considering day roost needs simultaneously across multiple spatial scales. Size and decay class of individual roosts are key ecological attributes for the Indiana bat, however, larger-scale stand structural components that are products of past and current land use interacting with environmental aspects such as landform also are important factors influencing roost-tree selection patterns.

Show MeSH
Related in: MedlinePlus