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Odion D.C.,University of California at Santa Barbara | Odion D.C.,Southern Oregon University | Hanson C.T.,Earth Island Institute | DellaSala D.A.,Geos Institute | And 2 more authors.
Open Ecology Journal | Year: 2014

The Northern Spotted Owl (Strix occidentalis caurina) is an emblematic, threatened raptor associated with dense, late-successional forests in the Pacific Northwest, USA. Concerns over high-severity fire and reduced timber harvesting have led to programs to commercially thin forests, and this may occur within habitat designated as "critical" for spotted owls. However, thinning is only allowed under the U.S. Government spotted owl guidelines if the long-term benefits clearly outweigh adverse impacts. This possibility remains uncertain. Adverse impacts from commercial thinning may be caused by removal of key habitat elements and creation of forests that are more open than those likely to be occupied by spotted owls. Benefits of thinning may accrue through reduction in high-severity fire, yet whether the firereduction benefits accrue faster than the adverse impacts of reduced late-successional habitat from thinning remains an untested hypothesis. We found that rotations of severe fire (the time required for high-severity fire to burn an area equal to the area of interest once) in spotted owl habitat since 1996, the earliest date we could use, were 362 and 913 years for the two regions of interest: the Klamath and dry Cascades. Using empirical data, we calculated the future amount of spotted owl habitat that may be maintained with these rates of high-severity fire and ongoing forest regrowth rates with and without commercial thinning. Over 40 years, habitat loss would be far greater than with no thinning because, under a "best case" scenario, thinning reduced 3.4 and 6.0 times more dense, late-successional forest than it prevented from burning in high-severity fire in the Klamath and dry Cascades, respectively. Even if rates of fire increase substantially, the requirement that the long-term benefits of commercial thinning clearly outweigh adverse impacts is not attainable with commercial thinning in spotted owl habitat. It is also becoming increasingly recognized that exclusion of high-severity fire may not benefit spotted owls in areas where owls evolved with reoccurring fires in the landscape. © Odion et al.; Licensee Bentham Open.


Dellasala D.A.,Geos Institute | Bond M.L.,Wild Nature Institute | Hanson C.T.,Earth Island Institute | Hutto R.L.,University of Montana | And 2 more authors.
Natural Areas Journal | Year: 2014

Complex early serai forests (CESFs) occupy potentially forested sites after a stand-replacement disturbance and before re-establishment of a closed-forest canopy. Such young forests contain numbers and kinds of biological legacies missing from those produced by commercial forestry operations. In the Sierra Nevada of California, CESFs are most often produced by mixed-severity fires, which include landscape patches burned at high severity. These forests support diverse plant and wildlife communities rarely found elsewhere in the Sierra Nevada. Severe fires are, therefore, essential to the region's ecological integrity. Ecologically detrimental management of CESFs, or unburned forests that may become CESF's following fire, is degrading the region's globally outstanding qualities. Unlike old-growth forests. CESFs have received little attention in conservation and reserve management. Thus, we describe important ecological attributes of CESFs and distinguish them from early serai conditions created by logging. We recommend eight best management practices in CESFs for achieving ecological integrity on federal lands in the mixed-conifer region of the Sierra Nevada.


Lee D.E.,Institute for Bird Populations | Lee D.E.,Wild Nature Institute | Bond M.L.,Institute for Bird Populations | Siegel R.B.,Institute for Bird Populations
Condor | Year: 2012

Understanding how habitat disturbances such as forest fire affect local extinction and probability of colonization-the processes that determine site occupancy-is critical for developing forest management appropriate to conserving the California Spotted Owl (Strix occidentalis occidentalis), a subspecies of management concern. We used 11 years of breeding-season survey data from 41 California Spotted Owl sites burned in six forest fires and 145 sites in unburned areas throughout the Sierra Nevada, California, to compare probabilities of local extinction and colonization at burned and unburned sites while accounting for annual and site-specific variation in detectability. We found no significant effects of fre on these probabilities, suggesting that fire, even fire that burns on average 32% of suitable habitat at high severity within a California Spotted Owl site, does not threaten the persistence of the subspecies on the landscape. We used simulations to examine how different allocations of survey effort over 3 years affect estimability and bias of parameters and power to detect differences in colonization and local extinction between groups of sites. Simulations suggest that to determine whether and how habitat disturbance affects California Spotted Owl occupancy within 3 years, managers should strive to annually survey ≥200 affected and ≥200 unaffected historical owl sites throughout the Sierra Nevada 5 times per year. Given the low probability of detection in one year, we recommend more than one year of surveys be used to determine site occupancy before management that could be detrimental to the Spotted Owl is undertaken in potentially occupied habitat. © The Cooper Ornithological Society 2012.


Lee D.E.,Wild Nature Institute | Bond M.L.,Wild Nature Institute | Borchert M.I.,U.S. Department of Agriculture | Tanner R.,Tanner Environmental Services
Journal of Wildlife Management | Year: 2013

Fire over the past decade has affected forests in the San Bernardino Mountains of southern California, providing an excellent opportunity to examine how this disturbance, and subsequent post-fire salvage logging, influenced California spotted owl (Strix occidentalis occidentalis) breeding-season site occupancy dynamics there and in the nearby San Jacinto Mountains. Using occupancy survey data from 2003 to 2011 for all-detections and pairs-only data, we estimated annual extinction and colonization probabilities at 71 burned and 97 unburned breeding-season sites before and after fire, while controlling for confounding effects of non-fire-related temporal variation and among-site differences in habitat characteristics. We found no statistically significant effects of fire or salvage logging on occupancy dynamics of spotted owls of southern California. However, we found some evidence that fire and logging effects could be biologically meaningful. For pairs data, the model-averaged mean of fire-related effects on colonization and extinction probabilities resulted in a 0.062 lesser site-occupancy probability in burned sites 1-year post-fire relative to unburned sites. Post-fire salvage logging reduced occupancy an additional 0.046 relative to sites that only burned. We documented a threshold-type relationship between extinction and colonization probabilities and the amount of forested habitat (conifer or hardwood tree cover types) that burned at high severity within a 203-ha core area around spotted owl nests and roost centroids. Sites where approximately 0-50 ha of forested habitat within the core area burned at high severity had extinction probabilities similar to unburned sites, but where more than approximately 50 ha of forested habitat burned severely, extinction probability increased approximately 0.003 for every additional hectare severely burned. The majority (75%) of sites burned below this threshold. Sites where high-severity fire affected >50 ha of forested habitat could still support spotted owls, so all burned sites should be monitored for occupancy before management actions such as salvage logging are undertaken that could be detrimental to the subspecies. We also recommend that managers strive to reduce human-caused ignitions along the wildland-urban interface, particularly at lower elevations where owl sites are at higher risk of extinction from fire. © 2013 The Wildlife Society. Copyright © The Wildlife Society, 2013.


Lee D.E.,Wild Nature Institute | Bond M.L.,Wild Nature Institute
Condor | Year: 2015

High-severity forest fire often is presumed to adversely affect the occupancy of territories by California Spotted Owls (Strix occidentalis occidentalis) because these owls are associated with mature and old-growth forests. We used single-season, multi-state occupancy statistics to estimate site occupancy probability for Spotted Owls at 45 historically occupied sites during the breeding season immediately following the 2013 Rim Fire, which was one of the largest forest fires on record in California. We quantified how occupancy probability was influenced by the amount of high-severity fire occurring in mature forested habitat within Protected Activity Centers (PACs). The model-averaged estimate of site-occupancy probability for at least a single owl was 0.922 (±SE=0.073), which was higher than other published occupancy probability estimates for this subspecies in either burned or long-unburned sites in the Sierra Nevada. Mean site-occupancy probability for pairs was 0.866 (±0.093), and most sites (33) were occupied by pairs. The amount of high-severity fire in the PAC did not affect pair occupancy. Occupancy probability by at least a single bird was negatively correlated with the amount of high severity fire in the PAC but remained >0.89 in 100% high-severity burned PACs. These data add to observations that California Spotted Owls continue to use post-fire landscapes, even when the fires were large and where large areas burned at high severity, suggesting that owls are not generally negatively impacted by high-severity fire. Based on this and other studies of Spotted Owls, fire, and logging, we suggest land managers consider burned forest within and surrounding PACs as potentially suitable California Spotted Owl foraging habitat when planning and implementing management activities, and we recommend against logging burned forest within at least 1.5 km of nests or roosts for the conservation and recovery of this declining subspecies.


Understanding interactions among site occupancy, reproduction, vegetation, and disturbance for threatened species can improve conservation measures, because important aspects of vegetation and disturbances may be identified and managed. We used 9 yr of survey data collected at 168 sites to investigate dynamic site occupancy and reproduction in a declining population of California Spotted Owls (Strix occidentalis occidentalis) in southern California, USA. We used multistate models to examine the relationship among owl site occupancy, reproduction, high-severity wildland fire, and postfire logging, while accounting for variation in vegetation characteristics and variation in detectability. Both occupancy and reproduction were positively correlated with successful reproduction in the previous year. Tree cover (ha) in a site's 203-ha core area also was positively correlated with both occupancy and reproduction. We detected no effect of disturbance covariates on reproduction, given that a site was occupied. Fire and logging covariates were both negatively correlated with the probability of site occupancy, and the effect sizes of these disturbances were large in sites that were occupied by owls that were nonreproductive the previous year (reduced 0.19 by fire and 0.26 by postfire logging), but small in sites that were occupied by owls that were reproductive the previous year (reduced 0.02 by fire and 0.03 by postfire logging). This study illustrates the important contribution of consistently occupied and productive breeding sites to this population of Spotted Owls, and demonstrates that both occupancy and reproduction at these productive sites exhibited negligible effects from disturbances. Our results suggest that sites with recent owl reproduction and sites with more tree cover in this study area should receive enhanced protection from management actions that modify vegetation utilized by Spotted Owls. © 2015 Cooper Ornithological Society.


Bond M.L.,Wild Nature Institute | Bradley C.,Center for Biological Diversity | Lee D.E.,Wild Nature Institute
Journal of Wildlife Management | Year: 2016

Forest fire is one of the most important ecological disturbances affecting habitat of the declining California spotted owl (Strix occidentalis occidentalis) population in southern California. We analyzed foraging location data collected 3 and 4 years post-fire, from 8 radio-tagged California spotted owls whose home ranges included forest burned in the 5,176-ha Slide Fire in the San Bernardino Mountains, California, USA. We analyzed foraging habitat selection with sensitivity analysis using 3 different spatial extents to define available resource area: utilization distribution, minimum convex polygon, and capture radius. At all 3 extents of available habitat these spotted owls selected foraging sites close to their territory centers and riparian areas. Resource selection functions indicated burned forests were generally used in proportion to their availability, with the exception of significant selection for moderate-severity burned forests farther from territory centers at the largest available habitat extent (capture radius). Riparian habitats should be preserved for California spotted owls in southern California, and forests burned by high-severity fire should be considered potentially suitable foraging habitat. We suggest researchers perform habitat selection analyses at multiple spatial extents of availability and describe the sensitivity of their results. © 2016 The Wildlife Society. © The Wildlife Society, 2016


Lee D.E.,Wild Nature Institute | Bond M.L.,Wild Nature Institute
Journal of Mammalogy | Year: 2016

Giraffes Giraffa camelopardalis are megafaunal browsers and keystone species in African savanna ecosystems. Range-wide population declines are suspected, but robust data are lacking. Tanzania holds the largest population of giraffe of any range state, and aerial surveys constitute most of Tanzania's giraffe population monitoring data, but their accuracy has not yet been assessed. An IUCN status assessment for giraffe is currently underway, and calibrating aerial surveys with ground-based surveys can quantify accuracy of the aerial surveys to ensure more reliable estimates of populations nationwide. We estimated giraffe density and abundance in the Tarangire Ecosystem in northern Tanzania using 2 ground survey methods, distance sampling and capture-mark-recapture, and compared our ground-based estimates with those from the most recent aerial survey in 4 sites. We found aerial survey estimates were biased low, while ground-based surveys were more precise and cost less. We computed correction factors to improve the accuracy of aerial surveys and suggested ways to further improve aerial survey methods. © 2016 American Society of Mammalogists.


Lee D.E.,Wild Nature Institute | Bond M.L.,Wild Nature Institute
Journal of Wildlife Diseases | Year: 2016

Giraffe skin disease (GSD) is a disorder of undetermined etiology that causes lesions on the forelimbs of Masai giraffe (Giraffa camelopardalis tippelskirchi). We estimated occurrence and prevalence of GSD in six wildlife conservation areas of Tanzania. The disjunct spatial pattern of occurrence implies that environmental factors may influence GSD. © Wildlife Disease Association 2016.


News Article | January 27, 2016
Site: www.techtimes.com

Wildlife animals are usually fierce-looking that it is impossible for anyone to not take notice. In Tanzania, an extremely rare white giraffe is attracting attention, but it is not because of usual reasons. North Carolina-based Wild Nature Institute (WNI) spotted the 15-month-old giraffe at the Tarangire National Park. The animal had a pale white skin color and a reddish mane. Fortunately, the group was able to capture photos. The giraffe was named Omo, after the name of a local detergent brand. The recent sighting is not the first time that scientists were able to spot the rare animal. Around the same time in 2015, Omo made its first appearance. "We are thrilled that she is still alive and well," the WNI blog post reads. Tarangire is the sixth biggest national park in Tanzania and has over 3,000 giraffe species. The white giraffe sighting is very rare that it has only been seen twice in Tarangire within the past two decades. People may think that the giraffe got its white color from albinism, which is characterized by lack of melanin in the skin. WNI's principal scientist Dr Derek Lee says that is not the case for Omo. Instead, he explained that the white giraffe has leucism, which involves the partial loss of pigmentation in all bodily cells, including the eyes. As a result, the Omo's eyes are red from the underlying blood vessels. Giraffe is the national animal of Tanzania, hence, it is unlawful to kill the creatures. Despite the rules, Lee says about 50 percent of giraffe populations are killed during its first year of life due to predators such as lions, leopards and hyenas. Bush meat poaching is also a problem, not only for the likes of Omo, but for all giraffe species as well. Luckily, Omo lives in a national park, where there are anti-poaching measures, giving the rare giraffe a better chance at survival. Lee and his wife are currently studying how humans can live with giraffes by going to places where both species frequently have contact. They hope to heighten the survival of Omo and its relatives through their conservation project. Other giraffes accepting Omo despite its unique appearance speaks volumes to humans, Lee suggests. Humans have this yearning for acceptance and tolerance amid differences, and the situation of the giraffes right now is good example of that.

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