BOOK REVIEW

Like its congener in North America (North American beaver [Castor canadensis]), the Eurasian beaver (Castor fiber) was locally extirpated from many parts of its range, largely because of over harvest and changing land use practices in the presence of an increasing human population. Similarly, both species also have responded well to changes in environmental awareness and wildlife management practices. Presently, both species are managed for the ecosystem services that they provide and the conflicts, or disservices, they create with humans (e.g., excessive flooding). The release of The Eurasian Beaver Handbook: Ecology and Management of Castor fiber (i.e., Eurasian Beaver Handbook) occurred at an opportune time because the public has growing interest in beaver ecology in the context of climate change. Eurasian Beaver Handbook was written by 12 individuals from 4 countries, the combination of which makes for a well-rounded, comprehensive guide

Black Bear

The American black bear (Ursus americanus, Figure 1) is a challenging species for wildlife agencies to manage due to its size, intelligence, extensive range, food habits, and adaptability, as well as societal views. In North America alone, agencies receive more than 40,000 complaints about black bear annually. Black bears are known as ‘food-driven’ animals, meaning most conflicts result from a bear’s drive to meet its nutritional needs. Not surprisingly, an overwhelming proportion of conflicts are related to their use of anthropogenic (human) food sources, such as garbage, bird food, and crops. Understanding what drives human-bear conflict is the first part of good management. Methods to manage human-bear conflicts can be grouped into two general categories: proactive and reactive. Proactive management attempts to change human behavior and prevent conflict, or keep it from recurring. Examples of proactive management include removing attractants, education and awareness, and exclusion. Conversely, reactive management attempts to change bear behavior or results in the lethal removal of the bear. Prior to any management action, there are important factors that managers and homeowners should consider. First, many of the methods described herein are only permissible to licensed personnel, such as state and federal biologists and wildlife managers. It is up to the individual to know which strategies are legal by reviewing local laws and agency websites. Also, it is important to note that any action plan should consider the side effects of the action and include a system for monitoring efficacy (short and long-term reactions of the bear). Documenting the season, time of day, type of conflict, and any information about the bear(s) involved is important for monitoring results. Be aware that the removal of the offending bear may open up its territory to other bear and conflicts, if the cause of the conflict is not mitigated

Evaluating the effects of mountain beaver (\u3ci\u3eAplodontia rufa\u3c/i\u3e) management on conifer stocking in western Oregon

Mountain beaver (Aplodontia rufa) is the most primitive rodent species in North America and is endemic to the Pacific Northwest, USA. Within their range, mountain beaver cause more conflict with conifer forest regeneration than any other vertebrate species. Most damage occurs as a result of clipping and browsing new seedlings, which reduces stocking density and delays stand development. An integrated approach using trapping and a registered toxicant (baiting) has been suggested as the most efficacious means to reduce seedling loss during stand initiation. We evaluated this management strategy in intensively managed conifer stands across two mountain ranges in western Oregon. Harvest units were divided equally and management (trapping and baiting) was implemented on a randomly selected half of each unit; the remaining halves served as an experimental control. We conducted damage assessments in fixed 0.04 ha circular plots at approximate 1, 6, and 12 month intervals after planting and initiation of management activities. After 12 months, we observed mountain beaver damage in 100% of control plots and 95% of treatment plots; however, there was a 79% decrease in the estimated odds of damage for plots where trapping and baiting was implemented (95% CI 43–92). Mean seedling height was 10.6 cm taller in treated plots than control plots 1 year post-planting (95% CI 4.1–17.1). Reoccupation of vacant burrows began within 1 month; within 12 months, only 5% of trapped plots remained unoccupied. Reported costs and benefits varied among harvest units, but management was less expensive ($154.09/ha) than the cost of interplanting gaps created by mountain beaver damage ($182.13/ha). Although trapping and baiting may not offer a one-time solution to damage problems, it is an effective tool in reducing damage, saving management costs, and meeting compliance with forest regulations and certification requirements

Habitat Use by Breeding Northern Bobwhites in Managed Old-Field Habitats in Mississippi

To better understand the proximate and ultimate cues associated with habitat selection in breeding northern bobwhites (Colinus virginianus), we compared habitat use vs. availability at 2 spatial scales equivalent to Johnson\u27s (1980) 2nd and 3,d order selection. We conducted the study in managed old-field habitats in Mississippi, from 1994 to 1996. We also estimated habitat use by broods with respect to availability, and quantified micro-habitat characteristics (4th order selection) at brood-rearing sites and nesting sites. Breeding bobwhites did not establish home ranges at random or allocate resources among patches in proportion to their availability. Breeding bobwhites, given a mosaic of seasonally manipulated old-field habitats, consistently used burned fields, disked fields, and areas with advanced woody succession to define breeding season home ranges. Bobwhites allocated their time and resources more to woody areas and fields that had received a combination of burning and disking. Broods consistently used burned/disked fields in proportion to availability; consistently avoided row crops and pastures; and generally preferred woody corridors. Vegetation characteristics at nest sites did not differ from random sites located within the same patch of habitat. Characteristics among nest sites were similar, yet successful nests were located in the proximity of more bare ground and less litter cover than unsuccessful nest sites. Brood site habitat characteristics were similar to nest sites; however, woody canopy (44.3%) and visual obstruction readings (59.0cm) at brood sites were significantly greater than nest sites (26.6% and 32.5cm)

Habitat selection by American beaverat multiple spatial scales

Background: Semiaquatic mammals require both aquatic and terrestrial habitats, particularly interfaces between the two habitats. As ecosystem engineers, American beaver (Castor canadensis) consume and fell a great amount of deciduous trees. We tested the prediction that open water and amounts of food resources, including hardwood forests (i.e., deciduous trees as the dominant form of vegetation), herbaceous and woody wetlands, and shrubs, would influence the second-order habitat selection (i.e., placing home ranges on the landscape) by American beaver, whereas the third-order habitat selection of American beaver would be associated with woody wetland and shrub edges. We investigated hierarchical habitat selection by American beaver using location data from very high frequency telemetry. Dirichlet-multinomial models were used to determine the second-order habitat selection at landscape scales. Bayesian spatial resource selection function was used to assess the third-order habitat selection within home ranges. Results: Second-order habitat selection by American beaver was associated with herbaceous wetland, shrubs, hardwood forest, grassland, and woody wetland more than open water bodies at landscape scales. At the third-order scale, American beaver selected herbaceous wetlands as well as the edges of shrubs and woody wetland within established home ranges. Conclusions: Spatial distributions of food resources affected both the second- and third-order habitat selection by American beaver. Herbaceous wetlands were more important habitat components than water bodies in the secondand third-order habitat selection by American beaver. Dirichlet-multinomial distribution models for the second-order habitat selection and Bayesian spatial resource selection functions for the third-order habitat selection do not need pseudo-absence locations, providing alternative approaches to the presence–absence methods for habitat selection by animals

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

Estimating the Total Economic Impact of Black Bear Peeling in Western Oregon Using GIS and REMI

In parts of the Pacific Northwest, black bears emerge from winter dens with depleted fat reserves and feed on mature conifers by stripping bark and consuming sugar-rich sapwood. Peeling by bears affects commercial conifers through direct loss of the tree or degraded log quality at stand harvest. Bears generally peel trees from 15-30 years old in intensively managed forests until preferred foods such as fruits and berries are available, and a single bear can peel several trees per day. Dying trees have a signature red canopy and are detected in annual aerial forest health surveys; however, trees that scar over peeling are not detected by aerial surveys. Previous studies reported results of damage summaries for northwest Oregon from flights, adjusted for bias; however, they offered no estimates of economic impact. Using landowner survey data, another study estimated an annual timber loss to bears at approximately $11.5 million across part of western Oregon. While informative, these estimates used broad assumptions to derive primary impacts and did not address secondary impacts. We used aerial health surveys, the national land cover database, and the Regional Economic Models Inc. (REMI) PI+ model to estimate the primary and secondary (indirect and induced) impacts of bear peeling in western Oregon. Because the accuracy and precision of aerial estimates (i.e., percentage of dead trees/polygon) was unknown, we calculated 4 scenarios of loss: 1$0.9-$89 million annually, and resulted in an annual loss of between 11 and 1,012 jobs in the state. We will explain our methodology in this study as well as current efforts to improve the accuracy and precision of damage estimates, and ultimately our understanding of the economic impacts of black bear peeling

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

Comparing Live-Capture Methods for Nutria: Single- Versus Multiple-Capture Cage Traps

Herbivory and burrowing by nutria (Myocastor coypus) cause substantial ecological and economic damage. Trapping is a common, effective practice for reducing nutria damage; however, trapping approaches must continually be adapted to keep pace with evolving animal welfare and ethical issues and to more effectively target pest species of interest. Our objective was to evaluate the efficacy of 2 nonlethal trap types for nutria: single-capture (SCT) and multi-capture (MCT) cage traps. We established 3 MCTs and 3 SCTs at each of 7 sites on a 10,500-ha mixed-use island located 15 km northwest of Portland, Oregon, USA. We pre-baited using carrots, apples, and sweet potatoes for ≥3 consecutive days before trapping. We checked traps daily, and an infrared motion camera was established near each MCT to document activity. We captured 26 nutria over 724 trap nights, and all captures occurred at 4 sites. Nutria captured by MCTs were larger (6.38 ± 1.68 [SD] kg, n = 10) than nutria captured by SCTs (4.21 ± 2.48 [SD] kg, n = 16; F1,25 = 5.51,P = 0.02). Camera surveillance showed multiple nutria present in an MCT on ≥2 occasions, although individual

Efficacy of Plastic Mesh Tubes in Reducing Herbivory Damage by the Invasive Nutria (Myocastor coypus) in an Urban Restoration Site

The restoration of stream corridors is becoming an increasingly important component of urban landscape planning, and the high cost of these projects necessitates the need to understand and address potential ecological obstacles to project success. The nutria (Myocastor coypus) is an invasive, semi-aquatic rodent native to South America that causes detrimental ecological impacts in riparian and wetland habitats throughout its introduced range, and techniques are needed to reduce nutria herbivory damage to urban stream restoration projects. We assessed the efficacy of standard Vexar® plastic mesh tubes in reducing nutria herbivory damage to newly established woody plants. The study was conducted in winter-spring 2009 at Delta Ponds, a 60-ha urban waterway in Eugene, Oregon. Woody plants protected by Vexar® tubes demonstrated 100% survival over the 3-month initial establishment period, while only 17% of unprotected plantings survived. Nutria demonstrated a preference for black cottonwood(Populus balsamifera ssp trichocarpa) over red osier dogwood (Cornus sericea) and willow (Salix spp). Camera surveillance showed that nutria were more active in unprotected rather than protected treatments. Our results suggest that Vexar® plastic mesh tubing can be an effective short-term herbivory mitigation tool when habitat use by nutria is low. Additionally, planting functionally equivalent woody plant species that are less preferred by nutria, and other herbivores, may be another method for reducing herbivory and improving revegetation success. This study highlights the need to address potential wildlife damage conflicts in the planning process for stream restoration in urban landscapes