Comparing Two Methods to Determine Nest Location of Golden Mice (\u3ci\u3eOchrotomys nuttalli\u3c/i\u3e)

Fluorescent powder tracking was compared with radiotelemetry to locate nests used by golden mice (Ochrotomys nuttalli), a semi-arboreal species. Fluorescent powder was not a successful method for determining nest location or movement patterns for golden mice. Many golden mice immediately climbed trees, whereas white-footed mice remained on the ground. Weather conditions can negatively affect the success of powder tracking. Although radiotelemetry successfully determined the locations of occupied nests, precise estimates of movements within a microhabitat could not be made

Discordant Data and Interpretation of Results from Wildlife Habitat Models

Wildlife habitat management is an important part of natural resource management. As a result, there are a large number of models and tools for wildlife habitat assessment. A consequence of the many assessment tools is inconsistency when comparing results between tools, which may lead to potential confusion management decisions. Our objective was to compare results from two wildlife habitat models – one being relatively coarse (HUC5) scale and not spatially dynamic and the other being finer scale spatial data based on a 30 m spatial resolution –for habitat assessment of three species across the West Cascades of Oregon: Northern spotted owl, pileated woodpecker, and western bluebird. The coarse-scale model predicted more habitat for the two specialist species (owl and bluebird), whereas the fine-scale model predicted more habitat for the generalist (woodpecker). Spatial evaluation of fine-scale models suggested habitat pattern that was not revealed by coarse-scale models. Differences in model assumptions, variables used, and flexibility of variable treatment account for differences in model performance. These findings suggest that cautious interpretation of results is needed given the constraints of each model. Coarse-scale models may help prioritize management treatments across space, but further fine-scale and site-specific analyses enhance information needed for making habitat management decisions

Estimating economic impact of black bear damage to western conifers at a landscape scale

Black bear (Ursus americanus) damage to trees in the Pacific Northwest is common, although volume and economic losses are unknown. Common measures to quantify bear damage to conifers at large scales rely solely on aerial estimates of red tree crowns (caused by complete girdling) and broad assumptions about stand characteristics. We surveyed 122 vulnerable stands in the Coast Range and western Cascades of Oregon using both aerial surveys and ground surveys. Then, we modeled 4 damage scenarios (Salvage; Total Loss; Root Disease; and Combined Damage) with the Forest Vegetation Simulator (FVS) growth and yield model and the Fuel Reduction Cost Simulator (FRCS). Damage polygons, digitized in real time from aerial surveys identifying red (dead or dying) tree crowns, overestimated bear damage by approximately 5-fold due to misclassification with root disease, and failed to detect partially peeled trees that contributed to economic loss. Damage polygons assessed from the air generally did not include red crowns, and were a mean distance of 58.8m (SE=8.8) from damage polygons’ outer edges to the nearest red crown. We accounted for mortality and volume losses from partially girdled trees that did not show red crowns in our Salvage scenario, whereas we assumed that all bear-peeled trees resulted in complete loss in the Total Loss scenario. At the landscape scale, economic loss was ≤0.35% of net present value under both damage scenarios, while processing bear damage trees (Salvage) was the most efficacious option. At the landscape scale, our worst-case scenario (Total Loss) resulted in an estimated loss of $56/ha to bear damage, 10-fold less than a previously reported estimate of$585/ha. Root disease was a more prevalent damage agent than bear damage but did not affect net present value at harvest. The majority (92%) of bear damage observed in ground surveys was older (\u3e 2 yrs) and existed at a low frequency (1.5 bear damaged trees/ha) and severity across the landscape. Our results suggest that black bear damage is not uniformly distributed and that perceived impact varies with spatial scale. On-the-ground monitoring of the status of bear damage across the western Oregon landscape will identify hot spots of severe peeling and provide an understanding of these changes over time

Estimating stand-level economic impacts of black bear damage to intensively managed forests

Black bears (Ursus americanus Pallas, 1780) peel conifers in early spring to forage on energy-rich vascular tissues, resulting in damage to timber stands. The objective of our study was to develop and demonstrate a conceptual framework and methods for estimating stand-level volume and economic losses from black bear damage. We created tree lists from surveys of healthy and bear-damaged trees in timber stands of western Washington and Oregon. The forest growth model Forest Vegetation Simulator (FVS) was used to project stand volume under two damage scenarios and an undamaged scenario. One damage scenario (salvage) accounted for mortality and volume losses of fully and partially girdled trees; a second scenario (total loss) assumed complete loss of all trees peeled by black bears, regardless of peeling severity. The Fuel Reduction Cost Simulator (FRCS) was applied to estimate the value of logs delivered to the mill after accounting for logging and hauling costs associated with harvest. Present value of stands was calculated to translate volume losses into economic losses associated with bear damage. Economic losses ranged from 4% to 16% (salvage) and from 17% to 46% (total loss) of net present value. Our approach can be adapted for other forest settings and for forest management plans that assess wildlife damage. L’ours noir (Ursus americanus Pallas, 1780) arrache l’écorce des conifères tôt au printemps pour se nourrir des tissus vasculaires riches en énergie et cause des dommages aux peuplements forestiers. L’objectif de notre étude consistait à élaborer et présenter un cadre conceptuel et des méthodes pour estimer à l’échelle du peuplement les pertes de volume ainsi que financières dues aux dommages causés par l’ours noir. Nous avons créé des listes d’arbres sains et d’arbres endommagés par les ours à partir des inventaires de peuplements forestiers de l’ouest des États de Washington et de l’Oregon. Un modèle de croissance de la forêt, le simulateur de végétation forestière, a été utilisé pour prévoir le volume d’un peuplement selon deux scénarios comportant des dommages et un troisième qui n’en comporte pas. Un scénario comportant des dommages (récupération) tenait compte de la mortalité et des pertes de volume des arbres partiellement et complètement annelés; un second scénario (perte totale) assumait la perte complète de tous les arbres endommagés par les ours noirs, peu importe la sévérité des dommages. Le simulateur du coût de réduction des combustibles a été appliqué pour estimer la valeur des billes livrées à l’usine après avoir pris en compte les coûts de la coupe et du débardage associés à la récolte. La valeur actualisée des peuplements a été calculée pour traduire les pertes de volume en pertes financières associées aux dommages causés par les ours. Les pertes financières variaient de 4–16 % (récupération) et de 17–46 % (perte totale) de la valeur actualisée nette. Notre approche peut être adaptée à d’autres situations ainsi qu’aux plans d’aménagement forestier qui évaluent les dommages causés par la faune

Use of Bridges as Day Roosts by Bats in Southern Illinois

From May through July 2001, and June through August 2002 we surveyed 232 bridges in 9 southern Illinois counties for the presence of roosting bats. Fifteen bridges (6.5%) had bats roosting at the time they were surveyed. We encountered big brown bats (Eptesicus fuscus) most frequently. Eastern pipestrelles (Pipestrellus subflavus), little brown bats (Myotis lucifugus), and northern long-eared bats (M. septentrionalis) also were found roosting under bridges. The number of bats per bridge ranged from 1 to \u3e100. Bats occurred in four of the five types of bridge designs surveyed. Of the 15 bridges with bats, 11 were rechecked at a later date to determine continuity of use. Seven of the 11 (63.6%) were being used by bats when rechecked. From this, we derived an estimated usage rate of 23.6 bridges (15/0.636) during the study, or about 10% of the 232 bridges surveyed. We could not determine relationships between bat presence and habitat features around bridges

Linking Wolf Diet to Changes in Marine and Terrestrial Prey Abundance

Since most wolf (Canis lupus) diet studies have been conducted in inland ecosystems, comparatively few data are available on diets of wolves in coastal systems. We investigated the diet of wolves in Glacier Bay, Alaska, from 12 May to 28 June in both 2010 and 2011. Although we identified 12 different prey species, including birds and small to medium-sized mammals, in wolf scats, moose (Alces alces) was the most frequent food item, observed in 80% of all scats. In contrast, a study conducted in 1993 in an area 37 km away found harbor seal (Phoca vitulina richardii) in 41% of wolf scats. Although we cannot account for differences in sampling design between the two studies, wolf diets may have changed between the two time periods.Puisque la plupart des études sur le régime alimentaire des loups (Canis lupus) ont été réalisées dans des écosystèmes situés à l’intérieur des terres, relativement peu de données existent sur le régime alimentaire des loups évoluant dans les environnements côtiers. Nous avons étudié l’alimentation des loups de Glacier Bay, en Alaska, du 12 mai au 28 juin 2010 et 2011. Bien que nous ayons retrouvé 12 proies différentes, y compris des espèces aviaires et des mammifères de taille petite ou de taille moyenne dans les déjections de loups, l’aliment le plus fréquemment rencontré, dans une mesure de 80 %, a été l’original, aussi appelé élan (Alces alces). Par contraste, une étude effectuée en 1993 dans une zone située à 37 kilomètres de distance a permis de découvrir du phoque commun (Phoca vitulina richardii) dans 41 % des déjections de loups. Bien que nous ne soyons pas en mesure de prendre en compte les différences d´échantillonnage entre les deux études, il est possible que le régime alimentaire des loups ait changé entre ces deux périodes.Большинство исследований рациона волка (Canis lupus) проводилось на внутриматериковых территориях, в то время как имеется сравнительно небольшое количество данных по рациону волка в прибрежных экосистемах. Ежегодно с 12 мая по 28 июня 2010-2011 гг. нашей группой проводились исследования рациона волков в бухте Глейшер-Бей, Аляска. Несмотря на то, что нами было определено 12 различных видов, используемых волками в качестве добычи, включая птиц, а также мелких и средних млекопитающих, останки лося (Alces alces) встречались в 80% экскрементов волков, указывая на то, что данный вид является наиболее частым пищевым объектом волка.В отличие от данных результатов, эксперимент, проведенный в 1993 г. на участке, удаленном от нашего на 37 км, обнаружил наличие останков тюленя (Phoca vitulina richardii) в 41% экскрементов волков. Несмотря на то, что мы не можем объяснить различия в выборке по каждому из исследований, их результаты указывают на то, что в период между двумя исследованиями в рационе волков могли произойти изменения

Divergent trends in ecosystem services under different climate-management futures in a fire-prone forest landscape

While ecosystem services and climate change are often examined independently, quantitative assessments integrating these fields are needed to inform future land management decisions. Using climate-informed state-and-transition simulations, we examined projected trends and trade-offs for a suite of ecosystem services under four climate change scenarios and two management scenarios (active management emphasizing fuel treatments and no management other than fire suppression) in a fire-prone landscape of dry and moist mixed-conifer forests in central Oregon, USA. Focal ecosystem services included fire potential (regulating service), timber volume (provisioning service), and potential wildlife habitat (supporting service). Projections without climate change suggested active management in dry mixed-conifer forests would create more open forest structures, reduce crown fire potential, and maintain timber stocks, while in moist mixed-conifer forests, active management would reduce crown fire potential but at the expense of timber stocks. When climate change was considered, however, trends in most ecosystem services changed substantially, with large increases in wildfire area predominating broad-scale trends in outputs, regardless of management approach (e.g., strong declines in timber stocks and habitat for closed-forest wildlife species). Active management still had an influence under a changing climate, but as a moderator of the strong climate-driven trends rather than being a principal driver of ecosystem service outputs. These results suggest projections of future ecosystem services that do not consider climate change may result in unrealistic expectations of benefits

Starting on the Right Foot: Carryover Effects of Larval Hydroperiod and Terrain Moisture on Post-metamorphic Frog Movement Behavior

Changing patterns of precipitation and drought will dramatically influence the distribution and persistence of lentic habitats. Pond-breeding amphibians can often respond to changes in habitat by plastically shifting behavioral and developmental trait response. However, fitness tradeoffs inherent in life history strategies can carry over to impact development, behavior, and fitness in later life stages. In this experiment, we investigated carryover effects of hydroperiod permanence on the movement behavior of newly-metamorphosed juvenile Northern Red-legged Frogs (Rana aurora). Frogs were raised through metamorphosis in mesocosms under either permanent or ephemeral hydroperiod conditions. After metamorphosis, individuals were removed from the mesocosms, measured, uniquely tagged with elastomer, and moved to holding terrariums. Movement behavior was quantified under two terrain conditions: a physiologically-taxing, dry runway treatment, or a control, moist runway treatment. Individuals were given 30 min to move down the 1 × 20m enclosed structure before distance was measured. We applied a hurdle model to examine two distinct components of movement behavior: (1) the probability of moving away from the start location, and (2) movement distance. We found that hydroperiod condition had an indirect carryover effect on movement via the relationship between individual size and the propensity to move. Individuals from ephemeral mesocosm conditions metamorphosed at a smaller size but showed increased growth rates as compared to individuals from permanent hydroperiod conditions. Individual snout-vent length and runway condition (moist or dry) were significant predictors of both aspects of movement behavior. Larger individuals were more likely to move down the runway and able to move a farther distance than smaller individuals. In addition to the influence of size, dry runway conditions reduced the probability of individuals moving from the start location, but increased the distance traveled relative to the moist runway. The demonstrated cumulative impact of stressors suggests the importance of addressing direct, indirect, and carryover effects of stressors throughout ontogeny

Use of Bridges as Day Roosts by Bats in Southern Illinois

ABSTRACT From May through July 2001, and June through August 2002 we surveyed 232 bridges in 9 southern Illinois counties for the presence of roosting bats. Fifteen bridges (6.5%) had bats roosting at the time they were surveyed. We encountered big brown bats (Eptesicus fuscus) most frequently. Eastern pipestrelles (Pipestrellus subflavus), little brown bats (Myotis lucifugus), and northern long-eared bats (M. septentrionalis) also were found roosting under bridges. The number of bats per bridge ranged from 1 to >100. Bats occurred in four of the five types of bridge designs surveyed. Of the 15 bridges with bats, 11 were rechecked at a later date to determine continuity of use. Seven of the 11 (63.6%) were being used by bats when rechecked. From this, we derived an estimated usage rate of 23.6 bridges (15/0.636) during the study, or about 10% of the 232 bridges surveyed. We could not determine relationships between bat presence and habitat features around bridges

Use of Anticoagulant Rodenticides in Single-Family Neighborhoods Along an Urban-Wildland Interface in California

Urbanization poses many threats for many wildlife species. In addition to habitat loss and fragmentation, non-target wildlife species are vulnerable to poisoning by rodenticides, especially acutely toxic second generation anticoagulant rodenticides (SGARs). Although such poisonings are well documented for birds and mammals worldwide, the pathways by which these widely available compounds reach non-target wildlife have not been adequately studied, particularly in urban landscapes. Long-term studies of wild carnivores in and around Santa Monica Mountains National Recreation Area, a national park north of Los Angeles, have documented \u3e85% exposure to anticoagulant rodenticides among bobcats, coyotes, and mountain lions. To investigate potential mechanisms of transfer of chemicals from residential users of rodenticides to non-target wildlife in the Santa Monica Mountains in Los Angeles County, California, we distributed surveys to residents in two study areas on the north (San Fernando Valley) and south (Bel Air-Hollywood Hills) slopes of these mountains. We assessed knowledge of residents about the environmental effects of rodenticides, and for information about individual application of chemicals. We asked for the same information from pest control operators (PCOs) in both study areas. Forty residents completed the survey in the San Fernando Valley area, and 20 residents completed the survey in Bel Air-Hollywood Hills. Despite the small number of total responses, we documented a number of important findings. Homeowners (as opposed to gardeners or PCOs) were the primary applicators of rodenticides, predominantly SGARs, and awareness of the hazards of secondary poisoning to wildlife was not consistent. Some residents reported improperly applying rodenticides (e.g., exceeding prescribed distances from structures), and in one instance a respondent reported observing dead animals outside after placing poison inside a structure. Improper application of SGARs that ignores label guidelines occurs in neighborhoods along the urban–wildland interface, thereby providing a transmission pathway for chemical rodenticides to reach native wildlife. Moreover, the responses suggest that even on-label use (e.g. placing poisons inside) can create risk for non-target wildlife