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Papers by Joseph Ganey

Ganey, Joseph L.; Benoit, Mary Ann. 2002. Using terrestrial ecosystem survey data to identify pot... more Ganey, Joseph L.; Benoit, Mary Ann. 2002. Using terrestrial ecosystem survey data to identify potential habitat for the Mexican spotted owl on National Forest System lands: a pilot study. Gen. Tech. Rep. RMRS-GTR-86. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 25 p. We assessed the usefulness of Terrestrial Ecosystem Survey (TES) data as a means of identifying habitat for the Mexican spotted owl (Strix occidentalis lucida) in three National Forests in Arizona. This spatial data set incorporates information on soils, vegetation, and climatic conditions in defining a set of ecological "map units" showing potential vegetation. We used three separate data sets consisting of spotted owl locations resulting from: (1) U.S. Forest Service (USFS) surveys; (2) mark-recapture sampling of 12 randomly selected "quadrats" ranging from 40 to 76 km 2 , conducted in conjunction with population monitoring efforts; and (3) moni...

ABSTRACT The Mexican spotted owl (Strix occidentalis lucida) is widely but patchily distributed t... more ABSTRACT The Mexican spotted owl (Strix occidentalis lucida) is widely but patchily distributed throughout the southwestern United States and the Republic of Mexico (Gutiérrez and others 1995, Ward and others 1995). This owl typically occurs in either rocky canyonlands or forested mountain and canyon systems containing mixed-conifer or pine-oak (Pinus spp. -Quercus spp.) forests, and its distribution mirrors the avail-ability of such areas (Ganey and Dick 1995, Ward and others 1995, USDI FWS 2012). Gene flow is known to occur across this fragmented range (Barrowclough and others 2006), but the mechanisms facilitating gene flow are poorly understood. Natal dispersal between disjunct mountain ranges and populations has been documented for dispersing juvenile Mexican spotted owls (Gutiérrez and others 1996, Arsenault and others 1997, Ganey and others 1998, Willey and van Riper 2000, Duncan and Speich 2002). In contrast, there are no documented records of breeding dispersal (defined as movement of a non-juvenile owl between territories where it had the op-portunity to breed, regardless of whether or not breeding occurred on these territories [Daniels and Walters 2000]) by non-juvenile owls. Thus, the potential role of breed-ing dispersal in gene flow within the range of this owl is unknown. Here, we report the circumstances surrounding recovery of a banded Mexican spotted owl that may represent the first documented case of long-distance breeding dispersal in this owl. We banded this owl on 9 August 1999, in the southern Black Range, New Mexico (fig.1), in conjunction with a study evaluating methods for monitor-ing population trend in Mexican spotted owls (Ganey and others 2004). The owl was identified as a female when banded based on vocalizations (Ganey 1990), and as an adult based on appearance of the retrices (Moen and others 1991), indicating

Forest Ecology and Management, 1999

Snags (standing dead trees) provide important habitat for forest wildlife, as well as a source of... more Snags (standing dead trees) provide important habitat for forest wildlife, as well as a source of coarse woody debris important in forest succession. Because of their importance, some land-management agencies have standards for snag retention on lands under their jurisdiction (e.g. U.S. Forest Service, British Columbia Ministry of Forestry). Despite these guidelines, however, little information is typically available on snag numbers or dynamics on these lands. As part of a long-term effort to monitor snag dynamics, snag populations were sampled on 114 1-ha plots randomly located across six Ranger Districts on two National Forests in northern Arizona. Sixty plots were located in ponderosa pine forest, with the remainder in mixed-conifer forest. Small snags and snags in later decay classes numerically dominated snag populations. Because large snags are most useful to forest wildlife, this suggests a need to retain large trees as future snags. Only 6.7 and 16.7% of plots in ponderosa pine and mixed-conifer forest, respectively, met or exceeded current U.S. Forest Service standards for retention of large snags (de®ned as snags !46 cm in diameter at breast height and 9 m in height) in this geographic region. Even plots with no evidence of timber or fuelwood harvest seldom met targets for retention of large snags, however. Only 30 and 32% of unlogged plots met or exceeded standards in ponderosa pine and mixed-conifer forest, respectively. This suggests that current standards for snag retention may be unrealistic, and that those standards may need to be reconsidered. Snag guidelines should be based on an understanding of both, snag dynamics and the requirements of snag-dependent wildlife species. #

Notes, 2011

your description here.

We summarized existing knowledge on winter movements and range and habitat use of radio-marked Me... more We summarized existing knowledge on winter movements and range and habitat use of radio-marked Mexican spotted owls. In light of that information, we evaluated the adequacy of current management guidelines. Seasonal movement or "migration" appears to be a regular feature of the winter ecology of Mexican spotted owls. Most radio-marked owls studied were resident in and around their breeding areas year-round, but some owls migrated in most populations studied. Owls that were year-round residents generally expanded their home range during the non-breeding season, and many exhibited spatial shifts in area used. Despite these shifts, however, overlap between seasonal ranges was relatively great for most individuals. For these owls, current guidelines aimed at conserving nesting habitat also would conserve areas used during the non-breeding season. Additional recovery plan guidelines aimed at protecting habitats with structure similar to nesting areas should be useful in protecting other areas used by resident owls expanding their range during winter. In contrast, migrating owls typically moved to lower elevations and into open habitats not used by breeding owls. Current guidelines do not protect these habitats. However, we currently have (1) no evidence that such habitats are limiting, (2) no evidence that special protection is necessary in these areas and/or habitats, (3) little information on which to base such protective measures if they are necessary, and (4) no objective way to identify important wintering areas used by migrating owls. Until better information is available, we see no compelling reason to develop specific guidelines for protection of wintering areas.

Canopy cover has been identified as an important correlate of Mexican spotted owl (Strix occident... more Canopy cover has been identified as an important correlate of Mexican spotted owl (Strix occidentalis lucida) habitat, yet management guidelines in a 1995 U.S. Fish and Wildlife Service recovery plan for the Mexican spotted owl did not address canopy cover. These guidelines emphasized parameters included in U.S. Forest Service stand exams, and canopy cover typically is not sampled in these inventories. Algorithms exist to estimate canopy cover from stand-exam data, but the accuracy of resulting estimates is unknown. We compared existing field data on observed canopy cover within forest stands used by radio-marked Mexican spotted owls with estimates derived from those analysis routines. Based on arbitrary criteria for minimum canopy cover, we also estimated proportions of these stands that would be misclassified by derived estimates. Canopy-cover estimates derived from stand-exam data differed widely from observed canopy cover in many stands, and derived estimates frequently misclassified stands based on canopy-cover criteria. These algorithms performed worst in mesic mixed-conifer forest, the forest type in which spotted owls occur most commonly. We conclude that existing algorithms for estimating canopy cover from stand-exam data are not useful in forest habitat for Mexican spotted owls.

- Abstract.-We recorded 98 species of neotropical migratory birds in vegetation types containing ... more - Abstract.-We recorded 98 species of neotropical migratory birds in vegetation types containing oaks in southeastern Arizona and southern California. Neotropical migrants used these areas as breeding and migration habitat. Little similarity was found in the neotropical bird assemblages of California and Arizona. Within Arizona, bird assem- blages were most similar between mixed-conifer forest and pine-oak woodland. Use of oaks for foraging ranged from 17.4% to 73.7% of the foraging attempts for the nine species studied. These birds each used species of oaks in unique proportions.

Snags (standing dead trees) are important components of forested habitats that contribute to ecol... more Snags (standing dead trees) are important components of forested habitats that contribute to ecological decay and recycling processes as well as providing habitat for many life forms. As such, snags are of special interest to land managers, but information on dynamics of snag populations is lacking. We modeled trends in snag populations in mixed-conifer and ponderosa pine (Pinus ponderosa) forests in northern Arizona using a Leslie matrix model developed by Raphael and Morrison (1987). Models were parameterized using data on snag abundance in five decay classes in 2002, transition rates of snags among decay classes from 1997 to 2002, and recruitment of snags into these decay classes from 1997 to 2002. Snags were sampled on randomly located, 1-ha plots (n = 52 and 58 plots in mixedconifer and ponderosa pine, respectively). These plots covered the entire elevational gradient occupied by these forest types and a wide range of stand conditions in both forest types. Trends were modeled separately for each forest type over a 30-yr time horizon. The models predicted that over this period: 1) overall snag densities would increase in both forest types, 2) densities of large snags would increase in both forest types, 3) despite these increases, densities of large snags would remain below target densities in both forest types, and 4) species composition and decay-class distributions would change only slightly in both forest types. The models described here were derived from snag data averaged over large landscapes and a wide range of stand conditions within forest types. These models thus are not suitable for modeling snag dynamics at the stand level, but rather provide a means for coarse-scale modeling of snag dynamics over large landscapes. Future inventories of snags on these plots (planned at five-year intervals) will provide a means to both test and improve model predictions.

TO increase understanding of roosting habitat of Mexican Spotted Owls (Strix occidentalis lucida)... more TO increase understanding of roosting habitat of Mexican Spotted Owls (Strix occidentalis lucida) and factors that influence use of roosting habitat, we sampled habitat characteristics at 1790 sites used for roosting by 28 radio-marked Mexican Spotted Owls in three study areas in Arizona and New Mexico. We explored potential patterns of variation in roost-site characteristics by estimating similarity among all

Snags (standing dead trees) are important components of forests that contribute to ecological pro... more Snags (standing dead trees) are important components of forests that contribute to ecological processes and provide habitat for many life forms. We monitored dynamics of snag populations on 1-ha plots in southwestern mixed-conifer (n 53 plots) and ponderosa pine (Pinus ponderosa, n 60 plots) forests in north-central Arizona from 1997 to 2002. Of 2,240 snags marked in 1997, at least

Aspart of a set of studies evaluating home-range size and habitat use of radio-markedMexican spot... more Aspart of a set of studies evaluating home-range size and habitat use of radio-markedMexican spotted owls (Strix occidentalis lucida), we sampled structural characteristics offorest stands within owl home ranges on two study areas in Arizona and New Mexico. Study areas were dominated by ponderosa pine (Pinus ponderosa)-Gambel oak (Quercus gambelii) forest (Arizona) or mixed-conifer forest (New Mexico). We describe structural

To provide infonnation'on comparative habitat use. we studied radiotagged Mexican sponed owls... more To provide infonnation'on comparative habitat use. we studied radiotagged Mexican sponed owls (Strir occidenralis lucida: n = i 3) and great horned owls (Bubo virginianrrs. n = 4) innorthem Arizona. Home-range sire (95% adaptive kernel estimate) did not differ signtficantly between species during either the breeding or nonbrceding season. Home ranges overlapped constderably between species. but overlap in use of

We compared use of seven habitat types to availability of those types within the home ranges of e... more We compared use of seven habitat types to availability of those types within the home ranges of eight radio-tagged Mexican Spotted Owls (Strix occidentalis lucida). When all habitat types were considered simultaneously, habitat use differed from habitat availability for each owl. Patterns of habitat use varied among individuals and with respect to activity. Owls generally foraged more than or as

Distribution and habitat use of Mexican Spotted Owls (Strix occidentalis lu- cida) in Arizona wer... more Distribution and habitat use of Mexican Spotted Owls (Strix occidentalis lu- cida) in Arizona were studied from 1984-1988. Owls were widely but patchily distributed throughout the state except for the arid southwestern portion. Distribution of the owl cor- responded with distribution of forested mountains and canyonlands within the state. Owls occurred either in rocky canyons or in any of several

The Journal of Wildlife Management, 2015

Snags (standing dead trees) are important components of forests that provide resources for numero... more Snags (standing dead trees) are important components of forests that provide resources for numerous species of wildlife and contribute to decay dynamics and other ecological processes. Managers charged with managing populations of snags need information about standing rates of snags and factors influencing those rates, yet such data are limited for ponderosa pine (Pinus ponderosa) and especially mixedconifer forests in the southwestern United States. We monitored standing rates of snags in 1-ha plots in Arizona mixed-conifer (n ¼ 53 plots) and ponderosa pine (n ¼ 60 plots) forests from 1997 through 2012. We used the Burnham live-dead, mark-resight model in Program MARK and multimodel inference to estimate standing rates during 5-year intervals while accounting for imperfect detection. Because snag standing rates may be influenced by plot characteristics, we used plots rather than snags as sampling units and conducted bootstrap analyses (500 iterations per model) to resample plots and estimate standing rates and associated parameters. We modeled standing rates in 3 discrete steps. First, we selected a parsimonious base model from a set of models including snag species, and then we evaluated models created by adding snag and plot covariates to the base model in steps 2 and 3, respectively. Snag standing rates differed among snag species and 5-year sampling intervals. Standing rates were positively related to snag diameter, negatively related to snag height, and were lower for snags with intact tops than for broken-topped snags. Standing rates also were positively related to topographic roughness, elevation, tree density, and an index of northness, and negatively related to slope and relative topographic exposure. Our results provide comparative data on standing rates of multiple species of snags based on a large and spatially extensive sample and rigorous analysis, and quantify the relative importance of several snag and plot characteristics on those rates. They indicate that modeling snag dynamics is complicated by both spatial and temporal variation in standing rates and identify areas where further work is needed to facilitate such modeling. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Forest Science, 2015

Large snags and logs provide important biological legacies and resources for native wildlife, yet... more Large snags and logs provide important biological legacies and resources for native wildlife, yet data on populations of large snags and logs and factors influencing those populations are sparse. We monitored populations of large snags and logs in mixed-conifer and ponderosa pine (Pinus ponderosa) forests in northern Arizona from 1997 through 2012. We modeled density of large snags and logs as a function of forest type, time period, and environmental characteristics of sampled plots. Our objective was to build models that best explained current densities of these structures using these available covariates. The best model for density of large snags indicated that snag density was greater in mixed-conifer than in ponderosa pine forests, lower in plots with evidence of past timber or fuelwood harvest than in plots lacking such evidence, and covaried positively with mean slope and distance to road. The best model for density of large logs indicated that log density was greater in mixed-conifer than in ponderosa pine forests and covaried positively with solar insolation and surface ratio (an index of topographic roughness). The best snag model predicted that current US Department of Agriculture (USDA) Forest Service guidelines for retention of large snags were met only in mixed-conifer forests lacking evidence of past harvest activity. In contrast, the USDA Forest Service guidelines for retention of large logs were met in both forest types. Our results suggest that ease of human access and management history influence density of large snags, that current snag guidelines are unlikely to be met without considering these impacts, and that those guidelines may not be readily attainable in much of the landscape. This article uses metric units; the applicable conversion factors are: centimeters (cm): 1 cm ϭ 0.39 in.; meters (m): 1 m ϭ 3.3 ft; kilometers (km): 1 km ϭ 0.6 mi; hectares (ha): 1 ha ϭ 2.47 ac.

Open Journal of Forestry, 2012

Down logs provide important ecosystem services in forests and affect surface fuel loads and fire ... more Down logs provide important ecosystem services in forests and affect surface fuel loads and fire behavior. Amounts and kinds of logs are influenced by factors such as forest type, disturbance regime, forest management, and climate. To quantify potential short-term changes in log populations during a recent globalclimate-change type drought, we sampled logs in mixed-conifer and ponderosa pine (Pinus ponderosa) forests in northern Arizona in 2004 and 2009 (n = 53 and 60 1-ha plots in mixed-conifer and ponderosa pine forests, respectively). Over this short time interval, density of logs, log volume, area covered by logs, and total length of logs increased significantly in both forest types. Increases in all log parameters were greater in mixed-conifer than in ponderosa pine forest, and spatial variability was pronounced in both forest types. These results document rapid increases in log populations in mixed-conifer forest, with smaller changes observed in ponderosa pine forest. These increases were driven by climate-mediated tree mortality which created a pulse in log input, rather than by active forest management. The observed increases will affect wildlife habitat, surface fuel loads, and other ecosystem processes. These changes are likely to continue if climate change results in increased warmth and aridity as predicted, and may require shifts in management emphasis.

The Southwestern Naturalist, 2004

To evaluate the hypothesis that spotted owls (Strix occidentalis) select habitats with cool micro... more To evaluate the hypothesis that spotted owls (Strix occidentalis) select habitats with cool microclimates to avoid high daytime temperatures, I sampled thermal regimes in nest areas used by Mexican spotted owls (S. o. lucida) in northern Arizona. I sampled air temperature at 30-min intervals in 30 pairs of nest and random sites from May through August and used the resulting thermal profiles to estimate a suite of diurnal temperature parameters. I estimated diurnal energy use and evaporative water loss, and compared these estimates and temperature parameters between nest and random areas. Owl nest areas were significantly cooler than random areas, and estimated evaporative water loss was significantly lower in nest areas than in random areas. In contrast, there was little difference in estimated diurnal energy use between nest and random areas. These results support the hypothesis that Mexican spotted owls select cool habitats. Use of these cooler habitats apparently reduces diurnal evaporative water loss relative to random areas, suggesting that water balance might be more important in habitat selection by spotted owls than previously realized. However, selection of cool nest areas apparently does not result in large energy savings, at least in this high-elevation study area (mean elevation at nest areas in this study was 2,230 m).

To better understand the habitat relationships of the Mexican spotted owl (Strix occidentalis luc... more To better understand the habitat relationships of the Mexican spotted owl (Strix occidentalis lucida), and how such relationships might influence forest management, we studied home-range and habitat use of radio-marked owls in ponderosa pine (Pinus ponderosa)-Gambel oak (Quercus gambeli~) forest. Annual home-range size (95% adaptive-kernel estimate) averaged 895 ha * 70 (SE) for 1 2 individuals and 997 ha + 186 (SE) for 7 pairs of owls. On average, the 75% adaptive-kernel contour (a probability contour containing 75% of the owl locations) included 32 and 30% of the annual home range for individuals and pairs, respectively, suggesting high concentration of activity in a relatively small portion ofthe home range. Relative area of three covertypes (ponderosa pine forest, pineaak forest, and meadow) did not differ between seasonal ranges, and owls used these covertypes in proportion to their relative area during both breeding and nonbreeding seasons. In contrast, relative area of four c...

Ganey, Joseph L.; Benoit, Mary Ann. 2002. Using terrestrial ecosystem survey data to identify pot... more Ganey, Joseph L.; Benoit, Mary Ann. 2002. Using terrestrial ecosystem survey data to identify potential habitat for the Mexican spotted owl on National Forest System lands: a pilot study. Gen. Tech. Rep. RMRS-GTR-86. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 25 p. We assessed the usefulness of Terrestrial Ecosystem Survey (TES) data as a means of identifying habitat for the Mexican spotted owl (Strix occidentalis lucida) in three National Forests in Arizona. This spatial data set incorporates information on soils, vegetation, and climatic conditions in defining a set of ecological "map units" showing potential vegetation. We used three separate data sets consisting of spotted owl locations resulting from: (1) U.S. Forest Service (USFS) surveys; (2) mark-recapture sampling of 12 randomly selected "quadrats" ranging from 40 to 76 km 2 , conducted in conjunction with population monitoring efforts; and (3) moni...

ABSTRACT The Mexican spotted owl (Strix occidentalis lucida) is widely but patchily distributed t... more ABSTRACT The Mexican spotted owl (Strix occidentalis lucida) is widely but patchily distributed throughout the southwestern United States and the Republic of Mexico (Gutiérrez and others 1995, Ward and others 1995). This owl typically occurs in either rocky canyonlands or forested mountain and canyon systems containing mixed-conifer or pine-oak (Pinus spp. -Quercus spp.) forests, and its distribution mirrors the avail-ability of such areas (Ganey and Dick 1995, Ward and others 1995, USDI FWS 2012). Gene flow is known to occur across this fragmented range (Barrowclough and others 2006), but the mechanisms facilitating gene flow are poorly understood. Natal dispersal between disjunct mountain ranges and populations has been documented for dispersing juvenile Mexican spotted owls (Gutiérrez and others 1996, Arsenault and others 1997, Ganey and others 1998, Willey and van Riper 2000, Duncan and Speich 2002). In contrast, there are no documented records of breeding dispersal (defined as movement of a non-juvenile owl between territories where it had the op-portunity to breed, regardless of whether or not breeding occurred on these territories [Daniels and Walters 2000]) by non-juvenile owls. Thus, the potential role of breed-ing dispersal in gene flow within the range of this owl is unknown. Here, we report the circumstances surrounding recovery of a banded Mexican spotted owl that may represent the first documented case of long-distance breeding dispersal in this owl. We banded this owl on 9 August 1999, in the southern Black Range, New Mexico (fig.1), in conjunction with a study evaluating methods for monitor-ing population trend in Mexican spotted owls (Ganey and others 2004). The owl was identified as a female when banded based on vocalizations (Ganey 1990), and as an adult based on appearance of the retrices (Moen and others 1991), indicating

Forest Ecology and Management, 1999

Snags (standing dead trees) provide important habitat for forest wildlife, as well as a source of... more Snags (standing dead trees) provide important habitat for forest wildlife, as well as a source of coarse woody debris important in forest succession. Because of their importance, some land-management agencies have standards for snag retention on lands under their jurisdiction (e.g. U.S. Forest Service, British Columbia Ministry of Forestry). Despite these guidelines, however, little information is typically available on snag numbers or dynamics on these lands. As part of a long-term effort to monitor snag dynamics, snag populations were sampled on 114 1-ha plots randomly located across six Ranger Districts on two National Forests in northern Arizona. Sixty plots were located in ponderosa pine forest, with the remainder in mixed-conifer forest. Small snags and snags in later decay classes numerically dominated snag populations. Because large snags are most useful to forest wildlife, this suggests a need to retain large trees as future snags. Only 6.7 and 16.7% of plots in ponderosa pine and mixed-conifer forest, respectively, met or exceeded current U.S. Forest Service standards for retention of large snags (de®ned as snags !46 cm in diameter at breast height and 9 m in height) in this geographic region. Even plots with no evidence of timber or fuelwood harvest seldom met targets for retention of large snags, however. Only 30 and 32% of unlogged plots met or exceeded standards in ponderosa pine and mixed-conifer forest, respectively. This suggests that current standards for snag retention may be unrealistic, and that those standards may need to be reconsidered. Snag guidelines should be based on an understanding of both, snag dynamics and the requirements of snag-dependent wildlife species. #

Notes, 2011

your description here.

We summarized existing knowledge on winter movements and range and habitat use of radio-marked Me... more We summarized existing knowledge on winter movements and range and habitat use of radio-marked Mexican spotted owls. In light of that information, we evaluated the adequacy of current management guidelines. Seasonal movement or "migration" appears to be a regular feature of the winter ecology of Mexican spotted owls. Most radio-marked owls studied were resident in and around their breeding areas year-round, but some owls migrated in most populations studied. Owls that were year-round residents generally expanded their home range during the non-breeding season, and many exhibited spatial shifts in area used. Despite these shifts, however, overlap between seasonal ranges was relatively great for most individuals. For these owls, current guidelines aimed at conserving nesting habitat also would conserve areas used during the non-breeding season. Additional recovery plan guidelines aimed at protecting habitats with structure similar to nesting areas should be useful in protecting other areas used by resident owls expanding their range during winter. In contrast, migrating owls typically moved to lower elevations and into open habitats not used by breeding owls. Current guidelines do not protect these habitats. However, we currently have (1) no evidence that such habitats are limiting, (2) no evidence that special protection is necessary in these areas and/or habitats, (3) little information on which to base such protective measures if they are necessary, and (4) no objective way to identify important wintering areas used by migrating owls. Until better information is available, we see no compelling reason to develop specific guidelines for protection of wintering areas.

Canopy cover has been identified as an important correlate of Mexican spotted owl (Strix occident... more Canopy cover has been identified as an important correlate of Mexican spotted owl (Strix occidentalis lucida) habitat, yet management guidelines in a 1995 U.S. Fish and Wildlife Service recovery plan for the Mexican spotted owl did not address canopy cover. These guidelines emphasized parameters included in U.S. Forest Service stand exams, and canopy cover typically is not sampled in these inventories. Algorithms exist to estimate canopy cover from stand-exam data, but the accuracy of resulting estimates is unknown. We compared existing field data on observed canopy cover within forest stands used by radio-marked Mexican spotted owls with estimates derived from those analysis routines. Based on arbitrary criteria for minimum canopy cover, we also estimated proportions of these stands that would be misclassified by derived estimates. Canopy-cover estimates derived from stand-exam data differed widely from observed canopy cover in many stands, and derived estimates frequently misclassified stands based on canopy-cover criteria. These algorithms performed worst in mesic mixed-conifer forest, the forest type in which spotted owls occur most commonly. We conclude that existing algorithms for estimating canopy cover from stand-exam data are not useful in forest habitat for Mexican spotted owls.

- Abstract.-We recorded 98 species of neotropical migratory birds in vegetation types containing ... more - Abstract.-We recorded 98 species of neotropical migratory birds in vegetation types containing oaks in southeastern Arizona and southern California. Neotropical migrants used these areas as breeding and migration habitat. Little similarity was found in the neotropical bird assemblages of California and Arizona. Within Arizona, bird assem- blages were most similar between mixed-conifer forest and pine-oak woodland. Use of oaks for foraging ranged from 17.4% to 73.7% of the foraging attempts for the nine species studied. These birds each used species of oaks in unique proportions.

Snags (standing dead trees) are important components of forested habitats that contribute to ecol... more Snags (standing dead trees) are important components of forested habitats that contribute to ecological decay and recycling processes as well as providing habitat for many life forms. As such, snags are of special interest to land managers, but information on dynamics of snag populations is lacking. We modeled trends in snag populations in mixed-conifer and ponderosa pine (Pinus ponderosa) forests in northern Arizona using a Leslie matrix model developed by Raphael and Morrison (1987). Models were parameterized using data on snag abundance in five decay classes in 2002, transition rates of snags among decay classes from 1997 to 2002, and recruitment of snags into these decay classes from 1997 to 2002. Snags were sampled on randomly located, 1-ha plots (n = 52 and 58 plots in mixedconifer and ponderosa pine, respectively). These plots covered the entire elevational gradient occupied by these forest types and a wide range of stand conditions in both forest types. Trends were modeled separately for each forest type over a 30-yr time horizon. The models predicted that over this period: 1) overall snag densities would increase in both forest types, 2) densities of large snags would increase in both forest types, 3) despite these increases, densities of large snags would remain below target densities in both forest types, and 4) species composition and decay-class distributions would change only slightly in both forest types. The models described here were derived from snag data averaged over large landscapes and a wide range of stand conditions within forest types. These models thus are not suitable for modeling snag dynamics at the stand level, but rather provide a means for coarse-scale modeling of snag dynamics over large landscapes. Future inventories of snags on these plots (planned at five-year intervals) will provide a means to both test and improve model predictions.

TO increase understanding of roosting habitat of Mexican Spotted Owls (Strix occidentalis lucida)... more TO increase understanding of roosting habitat of Mexican Spotted Owls (Strix occidentalis lucida) and factors that influence use of roosting habitat, we sampled habitat characteristics at 1790 sites used for roosting by 28 radio-marked Mexican Spotted Owls in three study areas in Arizona and New Mexico. We explored potential patterns of variation in roost-site characteristics by estimating similarity among all

Snags (standing dead trees) are important components of forests that contribute to ecological pro... more Snags (standing dead trees) are important components of forests that contribute to ecological processes and provide habitat for many life forms. We monitored dynamics of snag populations on 1-ha plots in southwestern mixed-conifer (n 53 plots) and ponderosa pine (Pinus ponderosa, n 60 plots) forests in north-central Arizona from 1997 to 2002. Of 2,240 snags marked in 1997, at least

Aspart of a set of studies evaluating home-range size and habitat use of radio-markedMexican spot... more Aspart of a set of studies evaluating home-range size and habitat use of radio-markedMexican spotted owls (Strix occidentalis lucida), we sampled structural characteristics offorest stands within owl home ranges on two study areas in Arizona and New Mexico. Study areas were dominated by ponderosa pine (Pinus ponderosa)-Gambel oak (Quercus gambelii) forest (Arizona) or mixed-conifer forest (New Mexico). We describe structural

To provide infonnation'on comparative habitat use. we studied radiotagged Mexican sponed owls... more To provide infonnation'on comparative habitat use. we studied radiotagged Mexican sponed owls (Strir occidenralis lucida: n = i 3) and great horned owls (Bubo virginianrrs. n = 4) innorthem Arizona. Home-range sire (95% adaptive kernel estimate) did not differ signtficantly between species during either the breeding or nonbrceding season. Home ranges overlapped constderably between species. but overlap in use of

We compared use of seven habitat types to availability of those types within the home ranges of e... more We compared use of seven habitat types to availability of those types within the home ranges of eight radio-tagged Mexican Spotted Owls (Strix occidentalis lucida). When all habitat types were considered simultaneously, habitat use differed from habitat availability for each owl. Patterns of habitat use varied among individuals and with respect to activity. Owls generally foraged more than or as

Distribution and habitat use of Mexican Spotted Owls (Strix occidentalis lu- cida) in Arizona wer... more Distribution and habitat use of Mexican Spotted Owls (Strix occidentalis lu- cida) in Arizona were studied from 1984-1988. Owls were widely but patchily distributed throughout the state except for the arid southwestern portion. Distribution of the owl cor- responded with distribution of forested mountains and canyonlands within the state. Owls occurred either in rocky canyons or in any of several

The Journal of Wildlife Management, 2015

Snags (standing dead trees) are important components of forests that provide resources for numero... more Snags (standing dead trees) are important components of forests that provide resources for numerous species of wildlife and contribute to decay dynamics and other ecological processes. Managers charged with managing populations of snags need information about standing rates of snags and factors influencing those rates, yet such data are limited for ponderosa pine (Pinus ponderosa) and especially mixedconifer forests in the southwestern United States. We monitored standing rates of snags in 1-ha plots in Arizona mixed-conifer (n ¼ 53 plots) and ponderosa pine (n ¼ 60 plots) forests from 1997 through 2012. We used the Burnham live-dead, mark-resight model in Program MARK and multimodel inference to estimate standing rates during 5-year intervals while accounting for imperfect detection. Because snag standing rates may be influenced by plot characteristics, we used plots rather than snags as sampling units and conducted bootstrap analyses (500 iterations per model) to resample plots and estimate standing rates and associated parameters. We modeled standing rates in 3 discrete steps. First, we selected a parsimonious base model from a set of models including snag species, and then we evaluated models created by adding snag and plot covariates to the base model in steps 2 and 3, respectively. Snag standing rates differed among snag species and 5-year sampling intervals. Standing rates were positively related to snag diameter, negatively related to snag height, and were lower for snags with intact tops than for broken-topped snags. Standing rates also were positively related to topographic roughness, elevation, tree density, and an index of northness, and negatively related to slope and relative topographic exposure. Our results provide comparative data on standing rates of multiple species of snags based on a large and spatially extensive sample and rigorous analysis, and quantify the relative importance of several snag and plot characteristics on those rates. They indicate that modeling snag dynamics is complicated by both spatial and temporal variation in standing rates and identify areas where further work is needed to facilitate such modeling. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Forest Science, 2015

Large snags and logs provide important biological legacies and resources for native wildlife, yet... more Large snags and logs provide important biological legacies and resources for native wildlife, yet data on populations of large snags and logs and factors influencing those populations are sparse. We monitored populations of large snags and logs in mixed-conifer and ponderosa pine (Pinus ponderosa) forests in northern Arizona from 1997 through 2012. We modeled density of large snags and logs as a function of forest type, time period, and environmental characteristics of sampled plots. Our objective was to build models that best explained current densities of these structures using these available covariates. The best model for density of large snags indicated that snag density was greater in mixed-conifer than in ponderosa pine forests, lower in plots with evidence of past timber or fuelwood harvest than in plots lacking such evidence, and covaried positively with mean slope and distance to road. The best model for density of large logs indicated that log density was greater in mixed-conifer than in ponderosa pine forests and covaried positively with solar insolation and surface ratio (an index of topographic roughness). The best snag model predicted that current US Department of Agriculture (USDA) Forest Service guidelines for retention of large snags were met only in mixed-conifer forests lacking evidence of past harvest activity. In contrast, the USDA Forest Service guidelines for retention of large logs were met in both forest types. Our results suggest that ease of human access and management history influence density of large snags, that current snag guidelines are unlikely to be met without considering these impacts, and that those guidelines may not be readily attainable in much of the landscape. This article uses metric units; the applicable conversion factors are: centimeters (cm): 1 cm ϭ 0.39 in.; meters (m): 1 m ϭ 3.3 ft; kilometers (km): 1 km ϭ 0.6 mi; hectares (ha): 1 ha ϭ 2.47 ac.

Open Journal of Forestry, 2012

Down logs provide important ecosystem services in forests and affect surface fuel loads and fire ... more Down logs provide important ecosystem services in forests and affect surface fuel loads and fire behavior. Amounts and kinds of logs are influenced by factors such as forest type, disturbance regime, forest management, and climate. To quantify potential short-term changes in log populations during a recent globalclimate-change type drought, we sampled logs in mixed-conifer and ponderosa pine (Pinus ponderosa) forests in northern Arizona in 2004 and 2009 (n = 53 and 60 1-ha plots in mixed-conifer and ponderosa pine forests, respectively). Over this short time interval, density of logs, log volume, area covered by logs, and total length of logs increased significantly in both forest types. Increases in all log parameters were greater in mixed-conifer than in ponderosa pine forest, and spatial variability was pronounced in both forest types. These results document rapid increases in log populations in mixed-conifer forest, with smaller changes observed in ponderosa pine forest. These increases were driven by climate-mediated tree mortality which created a pulse in log input, rather than by active forest management. The observed increases will affect wildlife habitat, surface fuel loads, and other ecosystem processes. These changes are likely to continue if climate change results in increased warmth and aridity as predicted, and may require shifts in management emphasis.

The Southwestern Naturalist, 2004

To evaluate the hypothesis that spotted owls (Strix occidentalis) select habitats with cool micro... more To evaluate the hypothesis that spotted owls (Strix occidentalis) select habitats with cool microclimates to avoid high daytime temperatures, I sampled thermal regimes in nest areas used by Mexican spotted owls (S. o. lucida) in northern Arizona. I sampled air temperature at 30-min intervals in 30 pairs of nest and random sites from May through August and used the resulting thermal profiles to estimate a suite of diurnal temperature parameters. I estimated diurnal energy use and evaporative water loss, and compared these estimates and temperature parameters between nest and random areas. Owl nest areas were significantly cooler than random areas, and estimated evaporative water loss was significantly lower in nest areas than in random areas. In contrast, there was little difference in estimated diurnal energy use between nest and random areas. These results support the hypothesis that Mexican spotted owls select cool habitats. Use of these cooler habitats apparently reduces diurnal evaporative water loss relative to random areas, suggesting that water balance might be more important in habitat selection by spotted owls than previously realized. However, selection of cool nest areas apparently does not result in large energy savings, at least in this high-elevation study area (mean elevation at nest areas in this study was 2,230 m).

To better understand the habitat relationships of the Mexican spotted owl (Strix occidentalis luc... more To better understand the habitat relationships of the Mexican spotted owl (Strix occidentalis lucida), and how such relationships might influence forest management, we studied home-range and habitat use of radio-marked owls in ponderosa pine (Pinus ponderosa)-Gambel oak (Quercus gambeli~) forest. Annual home-range size (95% adaptive-kernel estimate) averaged 895 ha * 70 (SE) for 1 2 individuals and 997 ha + 186 (SE) for 7 pairs of owls. On average, the 75% adaptive-kernel contour (a probability contour containing 75% of the owl locations) included 32 and 30% of the annual home range for individuals and pairs, respectively, suggesting high concentration of activity in a relatively small portion ofthe home range. Relative area of three covertypes (ponderosa pine forest, pineaak forest, and meadow) did not differ between seasonal ranges, and owls used these covertypes in proportion to their relative area during both breeding and nonbreeding seasons. In contrast, relative area of four c...