Search

Estimating bird and bat mortality at wind facilities typically involves searching for carcasses on the ground near turbines. Some fraction of carcasses inevitably lie outside the search plots, and accurate mortality estimation requires accounting for those carcasses using models to extrapolate from searched to unsearched areas. Such models should account for variation in carcass density with distance, and ideally also for variation with direction (anisotropy). We compare five methods of accounting for carcasses that land outside the searched area (ratio, weighted distribution, non-parametric, and two generalized linear models (glm)) by simulating spatial arrival patterns and the detection process to mimic observations which result from surveying only, or primarily, roads and pads (R&P) and applying the five methods. Simulations vary R&P configurations, spatial carcass distributions (isotropic and anisotropic), and per turbine fatality rates. Our results suggest that the ratio method is less accurate with higher variation relative to the other four methods which all perform similarly under isotropy. All methods were biased under anisotropy; however, including direction covariates in the glm method substantially reduced bias. In addition to comparing methods of accounting for unsearched areas, we suggest a semiparametric bootstrap to produce confidence-based bounds for the proportion of carcasses that land in the searched area.

To accurately estimate per turbine – or per megawatt – annual wildlife mortality at wind facilities, the raw counts of carcasses found must be adjusted for four major sources of imperfect detection: (1) fatalities that occur outside the monitoring period; (2) carcasses that land outside the monitored area; (3) carcasses that are removed by scavengers or deteriorate beyond recognition prior to detection; and (4) carcasses that remain undiscovered by searchers even when present. To accurately estimate regional or national annual wildlife mortality, data must come from a representative (or appropriately weighted) sample of facilities for which estimates of mortality account for all sources of imperfect detection. I argue that the currently available data in the United States and much of the world do not represent the impacts of wind power on wildlife because not all facilities conduct monitoring studies, not all study results are publicly available, and few studies adequately account for imperfect detection. I present examples illustrating the limitations of our current data and pitfalls of interpreting data without accurately adjusting for detection bias. I close by proposing a solution through a simplified monitoring process that can be applied at every facility as part of normal operations. Application of an unbiased estimator that accounts for all sources of imperfect detection would assure comparability of mortality estimates. Public access to reported estimates would achieve representation. With these data we could develop a clearer understanding of how wind power is affecting wildlife throughout the world and inform our efforts to address it.

The global potential for wind power generation is vast, and the number of installations is increasing rapidly. We review case studies from around the world of the effects on raptors of wind-energy development. Collision mortality, displacement, and habitat loss have the potential to cause population-level effects, especially for species that are rare or endangered. The impact on raptors has much to do with their behavior, so careful siting of wind-energy developments to avoid areas suited to raptor breeding, foraging, or migration would reduce these effects. At established wind farms that already conflict with raptors, reduction of fatalities may be feasible by curtailment of turbines as raptors approach, and offset through mitigation of other human causes of mortality such as electrocution and poisoning, provided the relative effects can be quantified. Measurement of raptor mortality at wind farms is the subject of intense effort and study, especially where mitigation is required by law, with novel statistical approaches recently made available to improve the notoriously difficult-to-estimate mortality rates of rare and hard-to-detect species. Global standards for wind farm placement, monitoring, and effects mitigation would be a valuable contribution to raptor conservation worldwide.

This article is a tutorial for the R-package carcass. It starts with a short overview of common methods used to estimate mortality based on carcass searches. Then, it guides step by step through a simple example. First, the proportion of animals that fall into the search area is estimated. Second, carcass persistence time is estimated based on experimental data. Third, searcher efficiency is estimated. Fourth, these three estimated parameters are combined to obtain the probability that an animal killed is found by an observer. Finally, this probability is used together with the observed number of carcasses found to obtain an estimate for the total number of killed animals together with a credible interval.

With wind energy production expanding rapidly, concerns about turbine-induced bird and bat fatality have grown and the demand for accurate estimation of fatality is increasing. Estimation typically involves counting carcasses observed below turbines and adjusting counts by estimated detection probabilities. Three primary sources of imperfect detection are 1) carcasses fall into unsearched areas, 2) carcasses are removed or destroyed before sampling, and 3) carcasses present in the searched area are missed by observers. Search plots large enough to comprise 100% of turbine-induced fatality are expensive to search and may nonetheless contain areas unsearchable because of dangerous terrain or impenetrable brush. We evaluated models relating carcass density to distance from the turbine to estimate the proportion of carcasses expected to fall in searched areas and evaluated the statistical cost of restricting searches to areas near turbines where carcass density is highest and search conditions optimal. We compared 5 estimators differing in assumptions about the relationship of carcass density to distance from the turbine. We tested them on 6 different carcass dispersion scenarios at each of 3 sites under 2 different search regimes. We found that even simple distance-based carcass-density models were more effective at reducing bias than was a 5-fold expansion of the search area. Estimators incorporating fitted rather than assumed models were least biased, even under restricted searches. Accurate estimates of fatality at wind-power facilities will allow critical comparisons of rates among turbines, sites, and regions and contribute to our understanding of the potential environmental impact of this technology. © 2014 The Wildlife Society.

We investigated the effect of contemporary forest harvesting practices on warm-season thermal regimes of headwater streams using a Before-After-Control-Intervention (BACI) design within a nested, paired watershed study. We applied harvesting treatments to four headwater tributaries of Hinkle Creek, designed in accordance with the Oregon Forest Practices Act. Therefore, fixed-width buffer strips containing overstory merchantable trees were not left adjacent to the four non-fish-bearing streams. The summer following harvesting, we observed a variable temperature response across the four harvested streams. Mean maximum daily stream temperatures ranged from 1.5 °C cooler to 1.0 °C warmer relative to pre-harvest years. We also observed significantly lower minimum and mean daily stream temperatures, and recorded particularly low temperatures in treatment streams on days that minimum stream temperatures in reference streams were high. At the watershed scale, we did not observe cumulative stream temperature effects related to harvesting 14% of the watershed area in multiple, spatially-distributed harvest units across four headwater catchments. At the watershed outlet, we observed no change to maximum, mean, or minimum daily stream temperatures. We attribute the lack of consistent temperature increases in headwater streams to shading provided by a layer of logging slash that deposited over the streams during harvesting, and to increased summer baseflows. Comparisons of canopy cover before and after harvesting indicate little change in canopy cover when logging slash is considered, indicating that logging slash affected energy balances within the streams. However, other ecosystem-level effects of logging slash in forest streams are difficult to predict. In order to devise optimum practices related to in-stream slash management, forest scientists and policymakers should continue to study and consider the potential impacts of logging slash to stream ecosystems.

Lower order, non-fish-bearing streams, often termed ‘‘headwater streams’’, have received minimal research effort and protection priority, especially in mesic forests where distinction between riparian and upland vegetation can be subtle. Though it is generally thought that breeding bird abundance is higher in riparian zones, little is known about species distributions when birds are in their juvenile stage – a critical period in terms of population viability. Using radio telemetry, we examined factors affecting habitat selection by juvenile Swainson’s thrushes during the post-breeding period in headwater basins in the Coast Range of Oregon, USA. We tested models containing variables expected to influence the amount of food and cover (i.e., deciduous cover, coarse wood volume, and proximity to stream) as well as models containing variables that are frequently measured and manipulated in forest management (i.e., deciduous and coniferous trees separated into size classes). Juvenile Swainson’s thrushes were more likely to select locations with at least 25% cover of deciduous, mid-story vegetation and more than 2.0 m 3 /ha of coarse wood within 40 m of headwater streams. We conclude that despite their small and intermittent nature, headwater streams and adjacent riparian areas are selected over upland areas by Swainson’s thrush during the postfledging period in the Oregon Coast Range. Published by Elsevier B.V.

Tree invasions have been documented throughout Northern Hemisphere high elevation meadows, as well as globally in many grass and forb-dominated ecosystems. Tree invasions are often associated with large-scale changes in climate or disturbance regimes, but are fundamentally driven by regeneration processes influenced by interactions between climatic, topographic, and biotic factors at multiple spatial scales. The purpose of this research was to quantify spatiotemporal patterns of meadow invasion; and how climate, larger landforms, topography, and overstory trees have interactively influenced tree invasion. We combined airborne Light Detection and Ranging (LiDAR) characterizations of landforms, topography, and overstory vegetation with historical climate, field measurements of snow depth, tree abundance, and tree ages to reconstruct spatial and temporal patterns of tree invasion over five decades in a subalpine meadow complex in the Oregon Cascade Range, USA. Proportion of meadow occupied by trees increased from 8 % in 1950 to 35 % in 2007. Larger landforms, topography, and tree canopies interactively mediated regional climatic controls of tree invasion by modifying depth and persistence of snow pack, while tree canopies also influenced seed source availability. Landscape context played an important role mediating snow depth and tree invasion; on glacial landforms tree invasion was negatively associated with spring snowfall, but on debris flows tree invasion was not associated with snow fall. The importance of snow, uncertain climate change impacts on snow, and mediation of snow by interacting and context dependent factors in complex mountain terrain poses substantial hurdles for understanding how these ecotones may respond to future climate conditions.

Studies examining the effects of human disturbance on avian parental behavior and reproductive success are fundamental to bird conservation. However, many such studies fail to also consider the influence of natural threats, a variable environment, and parental roles. Our work examines interactive relationships of cyclical (time of day, tide, temperature, seasonality) and stochastic (natural/human disturbance) processes with incubation patterns (attendance, bout lengths, recess rates) of the Black Oystercatcher (Haematopus bachmani), a shorebird of conservation concern. We used 24-hr-per-day video monitoring of 13 molecularly sexed breeding pairs to systematically examine incubation, revealing previously undocumented information that may inform conservation practices for the genus. Seven of 22 video-monitored nests failed, primarily from egg depredation by nocturnal mammals. Analyses of 3177 hr of video footage indicated a near doubling of incubation-bout lengths at night, corresponding to the in...

The need for research and development of effective approaches to weed control continues to increase globally. Adaptive protocols using diverse control methods are often required in ecological restoration as recruitment of native species is highly site-specific, species-specific, and experimental. The use of composted weed refuse to control other weeds may be a practical option; yet, the option is not well studied due to the accompanied risk of introducing weed propagules to areas where weed control is desired. Here, we tested the effectiveness of different physical control techniques including the use of mulch made by composting weed refuse on-site. English ivy (Hedera helix), a non-native, invasive species in the Pacific northwestern United States, was removed from a heavily invaded site, shredded, and composted. The mulch was compared with other methods of suppressing herb Robert (Geranium robertianum), another invasive species on-site. Five treatments were tested: flame-weeding, hand-pulling, mulching, hand-pulling followed by mulching, and flame-weeding followed by mulching. The mulch and pull/mulch treatments were the most effective, reducing G. robertianum cover by 92 and 86% of pre-treatment levels, respectively, and suppressing G. robertianum 2.9 and 1.6 times more than the control, respectively. The mechanism behind the effectiveness of the mulch is uncertain, but may be related to weed seed burial or the allelopathic potential of the mulch. Composting one invasive species to use as mulch to control another can be effective and merits trial elsewhere.

Wind-turbine operations are associated with bat mortality worldwide; minimizing these fatalities is critically important to both bat conservation and public acceptance of wind-energy development. We tested the effectiveness of raising wind-turbine cut-in speed – defined as the lowest wind speed at which turbines generate power to the utility system, thereby reducing turbine operation during periods of low wind speeds – to decrease bat mortality at the Casselman Wind Project in Somerset County, Pennsylvania, over a 2-year period. Observed bat mortality at fully operational turbines was, on average, 5.4 and 3.6 times greater than mortality associated with curtailed (ie non-operating) turbines in 2008 and 2009, respectively. Relatively small changes to wind-turbine operation resulted in nightly reductions in bat mortality, ranging from 44% to 93%, with marginal annual power loss (≤ 1% of total annual output). Our findings suggest that increasing turbine cut-in speeds at wind facilities in areas of conservati...

Counts of animal carcasses are often used to estimate fatality caused by disease, environmental accidents (oil spills, radiation leaks), or human structures (power lines, sky scrapers, wind turbines). The need to adjust raw carcass counts for imperfect detectability to produce unbiased estimates of fatality has long been recognized, but the accuracy and precision of some estimators used to make the adjustments have not been evaluated. In this paper, I formalize a conceptual model of fatality and the factors that lead to imperfect detection, primarily removal by scavengers before searches can be carried out and inability of searchers to find all remaining carcasses. I propose an estimator of fatality that adjusts for imperfect detectability. Through simulation I evaluate the statistical properties (bias and precision) of this estimator and two others commonly used to estimate fatality at wind power facilities, when sources and magnitudes of imperfect detectability vary. None of the estimators was always unbiased under all conditions. Bias in the proposed estimator never exceeded ±27% whereas bias in the other two estimators was always negative and exceeded that of the proposed estimator in 98% and 93% of the simulated conditions, respectively. The proposed estimator was relatively robust to variation in sources and magnitudes of imperfect detectability, but was sensitive to distributional assumptions regarding carcass removal rates and searcher efficiency. It offers significant improvement over two current estimators and provides relatively unbiased estimates of fatality that can be applied under a variety of conditions and survey protocols. Copyright © 2010 John Wiley & Sons, Ltd.

M. G. Betts (Matthew.Betts@oregonstate.edu), L. M. Ganio, M. M. P. Huso and N. A. Som, Dept of Forest Ecosystems and Society, Oregon State Univ., Corvallis, OR 97331, USA. F. Huettmann, Biology and Wildlife Dept, Inst. of Arctic Biology, Univ. of Alaska-Fairbanks, Fairbanks, AK 99775-7000, USA. J. Bowman, Ontario Ministry of Natural Resources, Wildlife Research and Development Section, 2140 East Bank Drive, Peterborough, ON K9J 7B8, Canada. B. A. Wintle, School of Botany, Environmental Science, The Univ. of Melbourne, Victoria, Australia.

Keen's myotis (Myotis keenii) has one of the most limited geographic distributions of any species of bat in North America. Because there is little knowledge of its roosting ecology, we examined selection of day-roosts in trees by male and female Keen's myotis at 3 spatial scales (tree, tree plot, and landscape) on Prince of Wales Island, southeastern Alaska, from May to September 2006. We selected variables known to influence roost selection by other tree-roosting bats for logistic regression models. We used Akaike's information criterion to rank all models within and between scales according to their ability to differentiate between characteristics of used and available roosts and we determined the effect of each variable with model-averaged coefficient estimates and associated odds ratios. We tracked 13 females and 6 males to 62 and 24 roosts in trees, respectively. Selection of day-roosts by males and females was most strongly influenced by characteristics of trees. The odds a tree was used for roosting by female Keen's myotis increased with the presence of defects, increasing diameter, and decreasing bark; increasing quadratic mean diameter in the tree plot; and decreasing distance to the nearest stream and increasing proportion of old growth in the landscape. Male Keen's myotis exhibited flexibility in types of roosts chosen, but the odds of a tree being used increased with decreasing bark, the presence of defects, and increasing slope-height. The odds a tree was used as a roost by males also increased with the increasing proportion of trees in early to late decay stages in the tree plot. Some habitat features differed between males and females at each spatial scale and differences are likely a reflection of the energetic demands associated with reproduction. We suggest that maintaining structural components characteristic of old-growth rain forest will promote conservation of Keen's myotis in southeastern Alaska.

Many wind-power facilities in the United States have established effective monitoring programs to determine turbine-caused fatality rates of birds and bats, but estimating the number of fatalities of rare species poses special difficulties. The loss of even small numbers of individuals may adversely affect fragile populations, but typically, few (if any) carcasses are observed during monitoring. If monitoring design results in only a small proportion of carcasses detected, then finding zero carcasses may give little assurance that the number of actual fatalities is small. Fatality monitoring at wind-power facilities commonly involves conducting experiments to estimate the probability (g) an individual will be observed, accounting for the possibilities that it falls in an unsearched area, is scavenged prior to detection, or remains undetected even when present. When g1, the total carcass count (X) underestimates the total number of fatalities (M). Total counts can be 0 when M is small or when M is large and g1. Distinguishing these two cases is critical when estimating fatality of a rare species. Observing no individuals during searches may erroneously be interpreted as evidence of absence. We present an approach that uses Bayes' theorem to construct a posterior distribution for M, i.e., P(M \ X, ĝ), reflecting the observed carcass count and previously estimated g. From this distribution, we calculate two values important to conservation: the probability that M is below a predetermined limit and the upper bound (M*) of the 100(1 - α)% credible interval for M. We investigate the dependence of M* on α, g, and the prior distribution of M, asking what value of g is required to attain a desired M for a given α. We found that when g-0.15, M* was clearly influenced by the mean and variance of ĝ and the choice of prior distribution for M, but the influence of these factors is minimal when g-0.45. Further, we develop extensions for temporal replication that can inform prior distributions of M and methods for combining information across several areas or time periods. We apply the method to data collected at a wind-power facility where scheduled searches yielded X = 0 raptor carcasses.

Dead wood is important to small mammals and is hypothesized to be used as travel paths. We evaluated the likelihood of different a priori models regarding sex- and season-specific differences and if quantity of wood in the environment influenced path selection of 41 Townsend’s chipmunks (Tamias townsendii) in coniferous forests of western Oregon with the spool-and-line method using an information-theoretic approach. On average, 50% (SD ¼ 4%) of the surficial portion of a chipmunk’s path was associated with downed wood and 79% (SD ¼ 10%) was on top of logs. Chipmunks disproportionately selected paths with downed wood relative to its availability and the model indicating that quantity of wood in the environment influenced path selection was 22.6 times more likely than the null model. At average wood densities (paths with 26% wood), a chipmunk was 3.0 times more likely to select locations with downed wood than locations without downed wood (95% confidence interval [95% CI] ¼ 2.5‐3.5). Furthermore, chipmunks selected wood that averaged 1.2 times larger in diameter than randomly available wood (95% CI ¼ 1.1‐1.3). Our findings document that Townsend’s chipmunks preferentially use downed wood and we hypothesize that downed wood may influence fitness or survival of individual chipmunks.

Disturbances and ecosystem recovery from disturbance both involve numerous processes that operate on multiple spatial and temporal scales. Few studies have investigated how gradients of disturbance intensity and ecosystem responses are distributed across multiple spatial resolutions and also how this relationship changes through time during recovery. We investigated how cover of non-native species and soil-aggregate stability (a measure of vulnerability to erosion by water) in surface and subsurface soils varied spatially during grazing by burros and cattle and whether patterns in these variables changed after grazer removal from Mojave National Preserve, California, USA. We compared distance from water and number of ungulate defecations — metrics of longer-term and recent grazing intensity, respectively, — as predictors of our response variables. We used information-theoretic analyses to compare hierarchical linear models that accounted for important covariates and allowed for interannual variation in the disturbance‐response relationship at local and landscape scales. Soil stability was greater under perennial vegetation than in bare interspaces, and surface soil stability decreased with increasing numbers of ungulate defecations. Stability of surface samples was more affected by time since removal of grazers than was stability of subsurface samples, and subsurface soil stability in bare spaces was not related to grazing intensity, time since removal, or any of our other predictors. In the high rainfall year (2003) after cattle had been removed for 1‐2 years, cover of all non-native plants averaged nine times higher than in the low-rainfall year (2002). Given the heterogeneity in distribution of large-herbivore impacts that we observed at several resolutions, hierarchical analyses provided a more complete understanding of the spatial and temporal complexities of disturbance and recovery processes in arid ecosystems.

We used detailed forest inventory data from 43 forests (3.5 × 103 – 115.2 × 103 stands each) and meteorological data from 30 weather stations located in proximity to these forests to assess the effects of disturbance and climate on biomass accumulation patterns across the forest zone of Russia. Chronosequences of biomass accumulation following disturbance were developed for each of the two to five dominant tree species in each forest using stand survey data collected by forest inventories in different regions of Russia between 1986 and 2003. These chronosequences represent changes in average live biomass of forest stands between age 10 and 210 years at 10-year intervals. The correlation of attributes of biomass accumulation (i.e., maximum biomass, biomass at age 40, and maximum biomass increment) with climatic and disturbance attributes was significant but weak (adjusted R2 = 0.20–0.37). The effect of the most influential disturbance attributes (percent clear-cut and percent old forest) was as strong or stronger than the effect of climatic attributes (30-year averages of the sum of positive daily temperatures and climate moisture index). The effect of tree species was significant, but weaker than the effects of climate or disturbance. Combining climate, disturbance, and species attributes generally improved the models (adjusted R2 = 0.37–0.53). The patterns of biomass change observed in chronosequences are influenced by the tendency of harvesting to target more productive forest stands of commercially valuable species, creating a disparity in productivity among the age cohorts. The apparent link between disturbance attributes of forests and biomass accumulation patterms in forest stands may be used to improve broad-scale modeling of changes in forest biomass with remotely sensed data.

In a recent paper, Smallwood et al. (2010) conducted a study to compare their “novel” approach to conducting carcass removal trials with what they term the “conventional” approach and to evaluate the effects of the different methods on estimated avian fatality at a wind power facility in California. A quick glance at Table 3 that succinctly summarizes their results and provides estimated fatality rates and 80% confidence intervals calculated using the 2 methods reveals a surprising result. The confidence intervals of all of their estimates and most of the conventional estimates extend below 0. These results imply that wind turbines may have the capacity to create live birds. But a more likely interpretation is that a serious error occurred in the calculation of either the average fatality rate or its standard error or both. Further evaluation of their methods reveals that the scientific basis for concluding that “many estimates of scavenger removal rates prior to [their] study were likely biased low due to scavenger swamping” and “previously reported estimates of avian fatality rates … should be adjusted upwards” was not evident in their analysis and results. Their comparison to conventional approaches was not applicable, their statistical models were questionable, and the conclusions they drew were unsupported. © 2013 The Wildlife Society.

Silvicultural practices, such as thinning, are increasingly performed both for commodity production and to help achieve biodiversity goals and promote ecological restoration. However, relatively little research has examined effects of thinning conifer forests on vertebrates. We experimentally manipulated stands using a randomized block design to evaluate influences of two thinning intensities on populations of diurnal breeding birds in western Oregon. We conducted point counts of birds seven times each year in 1994 (prior to treatment) and from 1995 through 2000 (subsequent to treatment). We analyzed data using multiple linear regression and information-theoretic approaches to model selection. Of the 22 species for which we had sufficient data for analysis, detections of nine species decreased and eight species increased in thinned stands relative to controls, and there was no strong evidence that thinning influenced numbers of five species. Of the 17 species that responded to thinning, the magnitude of response of eight species varied with thinning intensity; for each of these species, response was greatest in the more heavily thinned stands. Although no species was extirpated from stands following thinning, detections of Hutton's Vireos (Vireo huttoni), Golden-crowned Kinglets (Regulus satrapa), Brown Creepers (Certhia americana), Black-throated Gray Warblers (Dendroica nigrescens), and Varied Thrushes (Ixoreus naevius) decreased to less than half of the detections in controls in one or more treatment types, suggesting thinning significantly reduces their numbers. In contrast, American Robins (Turdus migratorius), Townsend's Solitaires (Myadestes townsendi), and Hammond's Flycatchers (Empidonax hammondii) were rare or absent in controls but regularly present in thinned stands, and detections of Western Tanagers (Piranga ludoviciana), Evening Grosbeaks (Coccothraustes vespertinus), and Hairy Woodpeckers (Picoides villosus) increased by threefold or more in thinned stands relative to controls. Only Pacific-slope Flycatchers (Empidonax difficilis), Warbling Vireos (Vireo gilvus), and Western Tanagers showed strong evidence of temporal trends in response. For these species, differences between numbers in controls and treated stands became more extreme through time. Our findings suggest that thinning densely stocked conifer stands in landscapes dominated by younger stands enhances habitat suitability for several species of birds, but that some unthinned patches and stands should be retained to provide refugia for species that are impacted by thinning.

Knowledge of the community structure of ectomycorrhizal fungi among successional forest age-classes is critical for conserving fungal species diversity. Hypogeous and epigeous sporocarps were collected from three replicate stands in each of three forest age-classes (young, rotation-age, and old-growth) of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) dominated stands with mesic plant association groups. Over four fall and three spring seasons, 48 hypogeous and 215 epigeous species or species groups were collected from sample areas of 6300 and 43 700 m2, respectively. Cumulative richness of hypogeous and epigeous species was similar among age-classes but differed between seasons. Thirty-six percent of the species were unique to an age-class: 50 species to old-growth, 19 to rotation-age, and 25 to young stands. Seventeen species (eight hypogeous and nine epigeous) accounted for 79% of the total sporocarp biomass; two hypogeous species, Gautieria monticola Harkn., and Hysterangium crassirhachis Zeller and Dodge, accounted for 41%. Average sporocarp biomass in young and rotation-age stands compared with old-growth stands was about three times greater for hypogeous sporocarps and six times greater for epigeous sporocarps. Average hypogeous sporocarp biomass was about 2.4 times greater in spring compared with fall and for epigeous sporocarps about 146 times greater in fall compared with spring. Results demonstrated differences in ectomycorrhizal fungal sporocarp abundance and species composition among successional forest age-classes.Key words: ectomycorrhizal fungi, sporocarp production, forest succession, Pseudotsuga menziesii, Tsuga heterophylla zone, biodiversity.

Wind turbines are causing unprecedented numbers of bat fatalities. Many fatalities involve tree-roosting bats, but reasons for this higher susceptibility remain unknown. To better understand behaviors associated with risk, we monitored bats at three experimentally manipulated wind turbines in Indiana, United States, from July 29 to October 1, 2012, using thermal cameras and other methods. We observed bats on 993 occasions and saw many behaviors, including close approaches, flight loops and dives, hovering, and chases. Most bats altered course toward turbines during observation. Based on these new observations, we tested the hypotheses that wind speed and blade rotation speed influenced the way that bats interacted with turbines. We found that bats were detected more frequently at lower wind speeds and typically approached turbines on the leeward (downwind) side. The proportion of leeward approaches increased with wind speed when blades were prevented from turning, yet decreased when blades could turn. Bats were observed more frequently at turbines on moonlit nights. Taken together, these observations suggest that bats may orient toward turbines by sensing air currents and using vision, and that air turbulence caused by fast-moving blades creates conditions that are less attractive to bats passing in close proximity. Tree bats may respond to streams of air flowing downwind from trees at night while searching for roosts, conspecifics, and nocturnal insect prey that could accumulate in such flows. Fatalities of tree bats at turbines may be the consequence of behaviors that evolved to provide selective advantages when elicited by tall trees, but are now maladaptive when elicited by wind turbines.

Yellow mycelia and cords of Piloderma fallax (Lib.) Stalp. were more frequently observed in old-growth stands than in younger managed stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Piloderma fallax frequency and percent cover data were collected from 900 plots in three replicate stands in each of three forest age classes over 2 years in both spring and fall. Piloderma fallax is strongly associated with stand age; it occurred in 57% of plots in old-growth, 6% of rotation-age, and 1% of young stands. Presence of Piloderma fallax was related to the percent cover of coarse woody debris (CWD) in decay class 5. Piloderma fallax was approximately 2.5 times more likely to occur in a plot with CWD decay class 5 present than in plots without. The probability that it would occur in a plot increased by approximately 20% for every 10% increase in percent cover of CWD decay class 5. However, the percent cover of Piloderma fallax was not strongly related to the percent cover of CWD in decay class 5. Frequency of occurrence did not differ among sampling times. Occurrence of Piloderma fallax may indicate suitable substrate for ectomycorrhizal fungi associated with CWD and may be important in forest management for the maintenance of biodiversity and old-growth components in young managed stands.Key words: Piloderma fallax, coarse woody debris, Pseudotsuga menziesii, forest management, ectomycorrhizal fungi, biodiversity.

We compare the number of species represented and the spatial pattern of reserve networks derived using five types of reserve selection algorithms on a set of vertebrate distribution data for the State of Oregon (USA). The algorithms compared are: richness-based heuristic algorithms (four variations), weighted rarity-based heuristic algorithms (two variations), progressive rarity-based heuristic algorithms (11 variations), simulated annealing, and a linear programming-based branch-and-bound algorithm. The linear programming algorithm provided optimal solutions to the reserve selection problem, finding either the maximum number of species for a given number of sites or the minimum number of sites needed to represent all species. Where practical, we recommend the use of linear programming algorithms for reserve network selection. However, several simple heuristic algorithms provided near-optimal solutions for these data. The near-optimality, speed and simplicity of heuristic algorithms suggests that they are acceptable alternatives for many reserve selection problems, especially when dealing with large data sets or complicated analyses.

The problem of selecting nature reserves has received increased attention in the literature during the past decade, and a variety of approaches have been promoted for selecting those sites to include in a reserve network. One set of techniques employs heuristic algorithms and thus provides possibly sub-optimal solutions. Another set of models and accompanying algorithms uses an integer programming formulation of the problem, resulting in an optimization problem known as the Maximal Covering Problem, or MCP. Solution of the MCP provides an optimal solution to the reserve site selection problem, and while various algorithms can be employed for solving the MCP they all suffer from the disadvantage of providing a single optimal solution dictating the selection of areas for conservation. In order to provide complete information to decision makers, the determination of all alternate optimal solutions is necessary. This paper explores two procedures for finding all such solutions. We describe the formulation and motivation of each method. A computational analysis on a data set describing native terrestrial vertebrates in the state of Oregon illustrates the effectiveness of each approach.

Large numbers of bats are killed by wind turbines worldwide and minimizing fatalities is critically important to bat conservation and acceptance of wind energy development. We implemented a 2-year study testing the effectiveness of an ultrasonic acoustic deterrent for reducing bat fatalities at a wind energy facility in Pennsylvania. We randomly selected control and treatment turbines that were searched daily in summer and fall 2009 and 2010. Estimates of fatality, corrected for field biases, were compared between treatment and control turbines. In 2009, we estimated 21-51% fewer bats were killed per treatment turbine than per control turbine. In 2010, we determined an approximate 9% inherent difference between treatment and control turbines and when factored into our analysis, variation increased and between 2% more and 64% fewer bats were killed per treatment turbine relative to control turbines. We estimated twice as many hoary bats were killed per control turbine than treatment turbine, and nearly twice as many silver-haired bats in 2009. In 2010, although we estimated nearly twice as many hoary bats and nearly 4 times as many silver-haired bats killed per control turbine than at treatment turbines during the treatment period, these only represented an approximate 20% increase in fatality relative to the pre-treatment period for these species when accounting for inherent differences between turbine sets. Our findings suggest broadband ultrasound broadcasts may reduce bat fatalities by discouraging bats from approaching sound sources. However, effectiveness of ultrasonic deterrents is limited by distance and area ultrasound can be broadcast, in part due to rapid attenuation in humid conditions. We caution that an operational deterrent device is not yet available and further modifications and experimentation are needed. Future efforts must also evaluate cost-effectiveness of deterrents in relation to curtailment strategies to allow a cost-benefit analysis for mitigating bat fatalities.

Bat Conservation International initiated a multi-year, pre-construction study in mid-summer 2009 to investigate patterns of bat activity and evaluate the use of acoustic monitoring to predict mortality of bats at the proposed Resolute Wind Energy Project (RWEP) in east-central Wyoming. The primary objectives of this study were to: (1) determine levels and patterns of activity for three phonic groups of bats (high-frequency emitting bats, low-frequency emitting bats, and hoary bats) using the proposed wind facility prior to construction of turbines; (2) determine if bat activity can be predicted based on weather patterns; correlate bat activity with weather variables; and (3) combine results from this study with those from similar efforts to determine if indices of pre-construction bat activity can be used to predict post-construction bat fatalities at proposed wind facilities. We report results from two years of pre-construction data collection.

The balance of forces determining the successful control of ragwort Senecio jacobaea by introduced insects was investigated in a field experiment by manipulating the time of disturbance, the level of interspecific plant competition, and the level of herbivory by the cinnabar moth Tyria jacobaeae and the ragwort flea beetle Longitarsus jacobaeae. We used a factorial design containing 0.25—m2 plots arranged as 4 Blocks × 2 Disturbance Time (plots were tilled in Fall 1986 or Spring 1987) × 3 Plant Competition levels (vegetation other than ragwort was Removed, Clipped, or Unaltered) × 2 Cinnabar Moth levels (Exposed, Protected) × 2 Flea Beetle levels (Exposed, protected). The response of ragwort was measured as colonization, survivorship, and reproduction of the first ragwort generation, establishment of juveniles in the second generation, and changes in ragwort biomass from 1987 through 1990. We also made annual measurements from 1987 through 1990 of the allocation of space (the limiting resource in the Unaltered competition treatment) among the categories ragwort, other species, litter, and open space. Natural enemy responses were characterized by relating variation in the concentration of enemies and the concentration of ragwort among patches. We found that abundant buried seed and localized disturbances combined to activate incipient ragwort outbreaks, and that interspecific plant competition and herbivory by the ragwort flea beetle combined to inhibit the increase and spread of incipient outbreaks. Time of disturbance had little effect on the outcome of biological control. Under conditions in the Removed and Clipped treatments (where there was sufficient open space for germination and establishment), reduction in seed production in the first generation caused by cinnabar moth larvae led to a reduction in plant numbers in the second generation, but caused only a weak effect on ragwort cover and no detectable effect on ragwort biomass over the longer term from 1986 through 1990. At the spatial scale examined, inhibition by the ragwort flea beetle and plant competition took the extreme form of elimination of all ragwort individuals except the pool of seed buried in the soil. Our findings lead us to (1) reject the view that successful biological control leads to a stable pest—enemy equilibrium on a local spatial scale, (2) strongly endorse "search and destroy" and weakly endorse "complementary enemies" strategies suggested by Murdoch et al. (1985) as ways to improve control, and (3) emphasize resource limitation in the pest at low density as a key feature distinguishing biological control of weeds from biological control of insects.

Widespread reports of bat fatalities caused by wind turbines have raised concerns about the impacts of wind power development. Reliable estimates of the total number killed and the potential effects on populations are needed, but it is crucial that they be based on sound data. In a recent BioScience article, Hayes (2013) estimated that over 600,000 bats were killed at wind turbines in the United States in 2012. The scientific errors in the analysis are numerous, with the two most serious being that the included sites constituted a convenience sample, not a representative sample, and that the individual site estimates are derived from such different methodologies that they are inherently not comparable. This estimate is almost certainly inaccurate, but whether the actual number is much smaller, much larger, or about the same is uncertain. An accurate estimate of total bat fatality is not currently possible, given the shortcomings of the available data.

We classified red spruce (Picearubens Sarg.) sites from northern Maine by radial growth release history. Two major releases were apparent for a majority of the sites. The first was a reduction and subsequent increase in radial increment in 1920. The second was an increase in radial increment from 1935 to 1955. Red spruce radial growth reduction in the 1960s is apparent only for sites released from 1935 to 1955 (approximately 54% of the sites in this study). These sites are now approaching the radial growth rates of the unreleased stands. Birch dieback is suggested as a probable contributor to the 1935–1955 red spruce growth increase and subsequent 1960s growth reduction.

We measured the concentrations of extractable bioactive compounds in heartwood of live yellow-cedar (Chamaecyparis nootkatensis) trees and five classes of standing snags (1–5, averaging 4, 14, 26, 51, and 81 years-since-death, respectively) to determine how the concentrations changed in the slowly deteriorating snags. Three individuals from each of these six condition classes were sampled at four sites spanning a 260-km distance across southeast Alaska, and the influence of geographic location on heartwood chemistry was evaluated. Cores of heartwood were collected at breast height and cut into consecutive 5-cm segments starting at the pith. Each segment was extracted with ethyl acetate and analyzed by gas chromatography. Concentrations of carvacrol, nootkatene, nootkatol, nootkatone, nootkatin, and total extractives (a sum of 16 compounds) for the inner (0–5 cm from pith), middle (5–10 cm from pith), and surface (outer 1.1–6.0 cm of heartwood) segments from each core were compared within each tree condition class and within segments across condition classes. Heartwood of class 1 and 2 snags had the same chemical composition as live trees. The first concentration changes begin to appear in class 3 snags, which coincides with greater heartwood exposure to the external environment as decaying sapwood sloughs away, after losing the protective outer bark. Within core segments, the concentrations of all compounds, except nootkatene, decrease between snag classes 2 and 5, resulting in the heartwood of class 5 snags having the lowest quantities of bioactive compounds, although not different from the amounts in class 4 snags. This decline in chemical defense is consistent with heartwood of class 5 snags being less decay-resistant than heartwood of live trees, as observed by others. The unique heartwood chemistry of yellow cedar and the slow way it is altered after death allow dead trees to remain standing for up to a century with a profound impact on the ecology of forests in southeast Alaska where these trees are in decline.

We are writing concerning our omission of a coauthor associated with our recent article: Manuela Huso, who was not included as a coauthor during the submission and revision stages of this work, made significant contributions to statistical aspects of this study that we believe merit coauthorship. These contributions involved: (1) assisting substantively with the overall statistical design, and (2) deriving an approach to numerical approximation of the area under the curve in a mass-loss function, which produced a single k-value from complex mass-loss patterns that allowed cross-species comparisons. To correct this, we would like to add Manuela Huso as a coauthor on the study, and that we remove Manuela Huso from the Acknowledgements. Please record the following information for Manuela Huso

Due to logistical and cost constraints, acidic deposition is rarely measured at forest research or sampling locations. A crucial first step to assessing the effects of acid rain on forests is an accurate estimate of acidic deposition at forest sample sites. We examine two methods (direct and indirect) for estimating sulfate deposition at atmospherically unmonitored forest sites. The direct method only uses directly measured deposition data, while the indirect method additionally incorporates precipitation measurements &om a spatially denser network of monitoring sites. Sulfate deposition values were estimated by point kriging using both the direct and indirect methods. By using the supplemental data from the precipitation monitoring network, estimates of sulfate deposition improved substantially, particularly at sites that are relatively isolated to the acid deposition monitoring network. Cross-validation procedures indicate that by using the indirect method, a reduction of approximately 20 to 25 percent in the predicted error sum of squares occurred

If arid sagebrush ecosystems lack resilience to disturbances or resistance to annual invasives, then alternative successional states dominated by annual invasives, especially cheatgrass (Bromus tectorum L.), are likely after fuel treatments. We identified six Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis Beetle & Young) locations (152–381 mm precipitation) that we believed had sufficient resilience and resistance for recovery. We examined impacts of woody fuel reduction (fire, mowing, the herbicide tebuthiuron, and untreated controls, all with and without the herbicide imazapic) on short-term dominance of plant groups and on important land health parameters with the use of analysis of variance (ANOVA). Fire and mowing reduced woody biomass at least 85% for 3 yr, but herbaceous fuels were reduced only by fire (72%) and only in the first year. Herbaceous fuels produced at least 36% more biomass with mowing than untreated areas during posttreatment years. Imazapic only reduced herbaceous biomass after fires (34%). Tebuthiuron never affected herbaceous biomass. Perennial tall grass cover was reduced by 59% relative to untreated controls in the first year after fire, but it recovered by the second year. Cover of all remaining herbaceous groups was not changed by woody fuel treatments. Only imazapic reduced significantly herbaceous cover. Cheatgrass cover was reduced at least 63% with imazapic for 3 yr. Imazapic reduced annual forb cover by at least 45%, and unexpectedly, perennial grass cover by 49% (combination of tall grasses and Sandberg bluegrass [Poa secunda J. Presl.]). Fire reduced density of Sandberg bluegrass between 40% and 58%, decreased lichen and moss cover between 69% and 80%, and consequently increased bare ground between 21% and 34% and proportion of gaps among perennial plants &spigt; 2 m (at least 28% during the 3 yr). Fire, mowing, and imazapic may be effective in reducing fuels for 3 yr, but each has potentially undesirable consequences on plant communities.