bluuebunny/crossref_metadata_2025 huggingface dataset:
Moisture as a determinant of habitat quality for a nonbreeding Neotropical migratory songbird
Authors: Smith Joseph A. M. , Reitsma Leonard R. , Marra Peter P.
Published: June 2010

Identifying the determinants of habitat quality for a species is essential for understanding how populations are limited and regulated. Spatiotemporal variation in moisture and its influence on food availability may drive patterns of habitat occupancy and demographic outcomes. Nonbreeding migratory birds in the neotropics occupy a range of habitat types that vary with respect to moisture. Using carbon isotopes and a satellite‐derived measure of habitat moisture, we identified a moisture gradient across home ranges of radio‐tracked Northern Waterthrush (Seiurus noveboracensis). We used this gradient to classify habitat types and to examine whether habitat moisture correlates with overwinter mass change and spring departure schedules of Northern Waterthrush over the late‐winter dry season in the tropics. The two independent indicators of moisture revealed similar gradients that were directly proportional to body mass change as the dry season progressed. Birds occupying drier habitats declined in body mass over the study period, while those occupying wetter habitats increased in body mass. Regardless of habitat, birds lost an average of 7.6% of their mass at night, and mass recovery during the day trended lower in dry compared with wet habitats. This suggests that daily incremental shortfalls in mass recovery can lead to considerable season‐long declines in body mass. These patterns resulted in consequences for the premigratory period, with birds occupying drier habitats having a delayed rate of fat deposition compared with those in wet habitats. Taken together with the finding that males, which are significantly larger than females, are also in better condition than females regardless of habitat suggests that high‐quality habitats may be limited and that there may be competition for them. The habitat‐linked variation in performance we observed suggests that habitat limitation could impact individual and population‐level processes both during and in subsequent periods of the annual cycle. The linkage between moisture and habitat quality for a migratory bird indicates that the availability of high‐quality habitats is dynamic due to variation in precipitation among seasons and years. Understanding this link is critical for ascertaining the impact of future climate change, particularly in the Caribbean basin, where a much drier future is predicted.
The trait contribution to wood decomposition rates of 15 Neotropical tree species
Authors: van Geffen Koert G. , Poorter Lourens , Sass-Klaassen Ute , van Logtestijn Richard S. P. , Cornelissen Johannes H. C.
Published: June 2010

The decomposition of dead wood is a critical uncertainty in models of the global carbon cycle. Despite this, relatively few studies have focused on dead wood decomposition, with a strong bias to higher latitudes. Especially the effect of interspecific variation in species traits on differences in wood decomposition rates remains unknown. In order to fill these gaps, we applied a novel method to study long‐term wood decomposition of 15 tree species in a Bolivian semi‐evergreen tropical moist forest. We hypothesized that interspecific differences in species traits are important drivers of variation in wood decomposition rates. Wood decomposition rates (fractional mass loss) varied between 0.01 and 0.31 yr−1. We measured 10 different chemical, anatomical, and morphological traits for all species. The species' average traits were useful predictors of wood decomposition rates, particularly the average diameter (dbh) of the tree species (R2= 0.41). Lignin concentration further increased the proportion of explained inter‐specific variation in wood decomposition (both negative relations, cumulativeR2= 0.55), although it did not significantly explain variation in wood decomposition rates if considered alone. When dbh values of the actual dead trees sampled for decomposition rate determination were used as a predictor variable, the final model (including dead tree dbh and lignin concentration) explained even more variation in wood decomposition rates (R2= 0.71), underlining the importance of dbh in wood decomposition. Other traits, including wood density, wood anatomical traits, macronutrient concentrations, and the amount of phenolic extractives could not significantly explain the variation in wood decomposition rates. The surprising results of this multi‐species study, in which for the first time a large set of traits is explicitly linked to wood decomposition rates, merits further testing in other forest ecosystems.
Refueling while flying: Foraging bats combust food rapidly and directly to power flight
Authors: Voigt Christian C. , Sörgel Karin , Dechmann Dina K. N.
Published: June 2010

Flying vertebrates, such as bats, face exceptionally high energy costs during active flapping flight. Once airborne, energy turnover may exceed basal metabolic rate by a factor of up to 15. Here, we asked whether fuel that powers flight originates from exogenous (dietary nutrients), endogenous sources (mostly body lipids or glycogen), or a combination of both. Since most insectivorous bats fly continuously over relatively long time periods during foraging, we assumed that slowly mobilized glycogen, although suitable for supporting brief sallying flights, is inadequate to power aerial insect‐hunting of bats. We hypothesized that the insect‐feedingNoctilio albiventrisrapidly mobilizes and combusts nutrients from insects it has just eaten instead of utilizing endogenous lipids. We used the stable carbon isotope ratio in the bats' exhaled breath (δ13Cbrth) to assess the origin of metabolized substrates of resting and flyingN. albiventrisin two nutritional conditions: fasted and recently fed. The breath of fasted resting bats was depleted in13C in relation to their insect diet (δ13Cdiet), indicating the combustion of13C depleted body lipids. In contrast to this, δ13Cbrthof bats that had recently fed closely matched δ13Cdietin both resting and flying bats, suggesting a quick mobilization of ingested nutrients for metabolism. In contrast to most non‐volant mammals, bats have evolved the ability to fuel their high energy expenditure rates through the rapid combustion of exogenous nutrients, enabling them to conquer the nocturnal niche of aerial insectivory.
Modeling spatial aggregation of finite populations
Authors: Zillio Tommaso , He Fangliang
Published: June 2010

Accurate description of spatial distribution of species is essential for correctly modeling macroecological patterns and thus to infer mechanisms of species coexistence. The Poisson and negative binomial distribution (NBD) are most widely used to respectively model random and aggregated distributions of species in infinitely large areas. As a finite version of the Poisson distribution, the binomial distribution is used to model random distribution of species populations in finite areas. Despite that spatial aggregation is the most widespread pattern and no species in nature are distributed in infinitely large areas, no model is currently available to describe spatial aggregation for species distributed in finite areas. Here we develop a finite counterpart of the NBD to model aggregated species in finite landscapes. Similar to the NBD, this new model also has a parameter k measuring spatial aggregation. When k → ∞, this model becomes the binomial distribution; when study area approaches infinite, it becomes the NBD. This model was extensively evaluated against the distributions of over 300 tree species in a 50‐ha stem‐mapping plot from Barro Colorado Island, Panama. The results show that when sampling area is small (relative to the study area), the new model and the NBD are of little difference. But the former correctly models spatial distribution at the finite limit at which the NBD fails. We reveal serious theoretical pathologies by using infinite models to approximate finite distribution and show the theoretical and practical advantages for using the new finite model for modeling species–area relationships, species occupancy and spatial distribution of rare species.
Mast seeding under increasing drought: results from a long‐term data set and from a rainfall exclusion experiment
Authors: Pérez-Ramos I. M. , Ourcival J. M. , Limousin J. M. , Rambal S.
Published: June 2010

Mast seeding, the synchronous, highly variable seed production among years, is very common in tree species, but there is no consensus about its main causes and the main environmental factors affecting it. In this study, we first analyze a long‐term data set on reproductive and vegetative growth of Quercus ilex in a mediterranean woodland in order to identify the main environmental drivers of interannual variation in flower and seed production and contrast the impact of climate vs. adaptive factors as main causes of masting. Second, we conducted an experiment of rainfall exclusion to evaluate the effects of an increasing drought (simulating predictions of global change models) on both reproductive processes. The annual seed crop was always affected by environmental factors related to the precipitation pattern, these abiotic factors disrupting the fruiting process at different periods of time. Seed production was strongly dependent upon water availability for the plant at initial (spring) and advanced (summer) stages of the acorn maturation cycle, whereas the final step of seed development was negatively affected by the frequency of torrential‐rain events. We also found clear evidence that seed masting in the study species is not only regulated by selective endogenous rhythms, but is mainly a physiological response to the variable environment. Our results from the rainfall exclusion experiment corroborated the conclusions obtained from the 26‐year fruiting record and demonstrated that the high interannual variation in seed crop was mainly determined by the success in seed development rather than by the flowering effort. Under a global change scenario, it could be expected that the drier conditions predicted by climate models reinforce the negative effects of summer drought on seed production, leading to negative consequences for tree recruitment and forest dynamics.
Functional traits and the growth–mortality trade‐off in tropical trees
Authors: Wright S. Joseph , Kitajima Kaoru , Kraft Nathan J. B. , Reich Peter B. , Wright Ian J. , Bunker Daniel E. , Condit Richard , Dalling James W. , Davies Stuart J. , Díaz Sandra , Engelbrecht Bettina M. J. , Harms Kyle E. , Hubbell Stephen P. , Marks Christian O. , Ruiz-Jaen Maria C. , Salvador Cristina M. , Zanne Amy E.
Published: June 2010

A trade‐off between growth and mortality rates characterizes tree species in closed canopy forests. This trade‐off is maintained by inherent differences among species and spatial variation in light availability caused by canopy‐opening disturbances. We evaluated conditions under which the trade‐off is expressed and relationships with four key functional traits for 103 tree species from Barro Colorado Island, Panama. The trade‐off is strongest for saplings for growth rates of the fastest growing individuals and mortality rates of the slowest growing individuals (r2 = 0.69), intermediate for saplings for average growth rates and overall mortality rates (r2 = 0.46), and much weaker for large trees (r2 ≤ 0.10). This parallels likely levels of spatial variation in light availability, which is greatest for fast‐ vs. slow‐growing saplings and least for large trees with foliage in the forest canopy. Inherent attributes of species contributing to the trade‐off include abilities to disperse, acquire resources, grow rapidly, and tolerate shade and other stresses. There is growing interest in the possibility that functional traits might provide insight into such ecological differences and a growing consensus that seed mass (SM), leaf mass per area (LMA), wood density (WD), and maximum height (Hmax) are key traits among forest trees. Seed mass, LMA, WD, and Hmax are predicted to be small for light‐demanding species with rapid growth and mortality and large for shade‐tolerant species with slow growth and mortality. Six of these trait–demographic rate predictions were realized for saplings; however, with the exception of WD, the relationships were weak (r2 < 0.1 for three and r2 < 0.2 for five of the six remaining relationships). The four traits together explained 43–44% of interspecific variation in species positions on the growth–mortality trade‐off; however, WD alone accounted for >80% of the explained variation and, after WD was included, LMA and Hmax made insignificant contributions. Virtually the full range of values of SM, LMA, and Hmax occurred at all positions on the growth–mortality trade‐off. Although WD provides a promising start, a successful trait‐based ecology of tropical forest trees will require consideration of additional traits.
Estimating dispersal potential for marine larvae: dynamic models applied to scleractinian corals
Authors: Connolly Sean R. , Baird Andrew H.
Published: June 2010

Dispersal influences ecological dynamics, evolution, biogeography, and biodiversity conservation, but models of larval dispersal in marine organisms make simplifying assumptions that are likely to approximate poorly the temporal dynamics of larval survival and capacity for settlement. In particular, larval mortality rates are typically assumed to be constant throughout larval life; and all larvae are frequently assumed to acquire and lose competence at the same time. To improve upon these assumptions, we here develop simple models of dispersal potential that incorporate rates of mortality, and acquisition and loss of settlement competence. We fit these models to empirical competence and survival data for five scleractinian coral species, to test the models' ability to characterize empirical survival and competence patterns, and to estimate the dispersal potential implied by those patterns. The models fit the data well, incorporating qualitative features of competence and survival that traditional approaches to modeling dispersal do not, with important implications for dispersal potential. Most notably, there was high within‐cohort variation in the duration of the competent period in all species, and this variation increases both self‐recruitment and long‐distance dispersal compared with models assuming a fixed competent period. These findings help to explain the seeming paradox of high genetic population structure, coupled with large geographic range size, observed in many coral species. More broadly, our approach offers a way to parsimoniously account for variation in competence dynamics in dispersal models, a phenomenon that our results suggest has important effects on patterns of connectivity in marine metapopulations.
Ocean warming increases threat of invasive species in a marine fouling community
Authors: Sorte Cascade J. B. , Williams Susan L. , Zerebecki Robyn A.
Published: June 2010

We addressed the potential for climate change to facilitate invasions and precipitate shifts in community composition by testing effects of ocean warming on species in a marine fouling community in Bodega Harbor, Bodega Bay, California, USA. First, we determined that introduced species tolerated significantly higher temperatures than natives, suggesting that climate change will have a disproportionately negative impact on native species. Second, we assessed the temperature dependence of survival and growth by exposing juveniles to an ambient control temperature and increased temperatures predicted by ocean warming scenarios (+3°C and +4.5°C) in laboratory mesocosms. We found that responses differed between species, species origins, and demographic processes. Based on the temperature tolerance, survival, and growth results, we predict that, as ocean temperatures increase, native species will decrease in abundance, whereas introduced species are likely to increase in this system. Facilitation of invasions by climate change may already be underway; locally, invasive dominance has increased concurrent with ocean warming over the past ∼40 years. We suggest that the effects of climate change on communities can occur via both direct impacts on the diversity and abundance of native species and indirect effects due to increased dominance of introduced species.
Childhood Learning History Origins of Adult Pain Anxiety
Authors: Watt Margo C. , Stewart Sherry H. , Moon Erin , Terry Lesley L.
Published: June 2010

Pain anxiety refers to a range of cognitive (catastrophic thinking), behavioral (escape and avoidance), and physiological (heightened arousal) responses to pain (McCracken & Gross). Greater pain anxiety is associated with greater pain severity, disability, and distress. This retrospective study investigated learning history experiences related to the development of pain anxiety in a sample of 198 undergraduates (147 women, 51 men). Childhood instrumental and, to a more limited extent, vicarious learning experiences with pain were positively associated with levels of pain anxiety in adulthood. The physical concerns component of anxiety sensitivity (AS: fear of arousal-related somatic sensations), but not AS-psychological or social concerns or trait anxiety, was found to mediate the relationship between childhood instrumental learning experiences with pain and pain avoidance behavior, cognitive anxiety, and physiological anxiety in adulthood. Both AS physical concerns and, to a lesser extent trait anxiety, mediated the relationship between childhood instrumental learning experiences with pain and fearful thinking about pain in adulthood. Finally, AS physical concerns, but not AS-psychological or social concerns or trait anxiety, also was found to mediate the relationship between childhood observational learning experiences with pain and pain cognitive anxiety and fearful thinking in adulthood.
Assessment of Total Antioxidant Capacity and the Use of Vitamin C in the Treatment of Non‐Smokers With Chronic Periodontitis
Authors: Abou Sulaiman Ali E. , Shehadeh Rana M.H.
Published: June 2010

Background: Several recent studies have indicated that total antioxidant capacity (TAOC) of plasma seems to be compromised in chronic periodontitis (ChP). The aim of this study is to investigate plasma TAOC in patients with ChP and to assess the effects of vitamin C as an adjunct to non‐surgical periodontal treatment.

Methods: The study population consisted of 60 subjects: 30 diagnosed with ChP and 30 matched controls. Furthermore, patients from the ChP group were randomly allocated into ChP1 (15 patients received non‐surgical treatment with adjunctive dose of vitamin C) and ChP2 (15 patients received non‐surgical periodontal treatment alone). Plasma TAOC levels were measured by an ABTS assay at baseline and 1 month post‐therapy.

Results: Plasma TAOC levels were significantly lower in ChP patients than controls (P <0.001). The periodontal therapy resulted in increasing plasma TAOC and improvements in clinical measures among both ChP1 and ChP2 groups (P <0.001). However, the adjunctive dose of vitamin C did not offer additional effect (P >0.05).

Conclusions: ChP is significantly associated with lower levels of plasma TAOC. The non‐surgical periodontal therapy seems to reduce the oxidative stress during the periodontal inflammation. However, the use of adjunctive vitamin C still needs further investigation.
Enhanced Degradation of Chlorobenzene in Aqueous Solution Using Microwave‐Induced Zero‐Valent Iron and Copper Particles
Authors: Lee Chien‐Li , Jou Chih‐Ju G. , Wang H. Paul
Published: June 2010

Microwaves were applied to reduce the activation energy of chlorobenzene in aqueous solution and enhance its removal using nano‐scale zero‐valent iron (Fe0) or zero‐valent copper (Cu0) particles as dielectric media. When Fe0 and Cu0 particles absorb microwave energy, the electrical potential difference causes the metal electrons to rotate faster, thus producing more heat. The microwave‐irradiated metal particles reduced the chlorobenzene activation energy by 6.1 kJ/mol (13.3 kJ/mol versus 19.4 kJ/mol) for Fe0 and 5.4 kJ/mol (15.8 kJ/mol versus 21.4 kJ/mol) for Cu0 and enhanced the chlorobenzene removal 4.1 times (82.8% versus 20.4%) for Fe0 and 3.7 times (72.1% versus 19.5%) for Cu0. The Fe0 has a higher standard reduction potential than Cu0; it is capable of removing more chlorobenzene than Cu0 (82.8% versus 72.1%). Using the microwave‐induced nano‐scale iron or copper particle is effective in treating toxic organic substances, as demonstrated in this study.
Decolorization of Drimarene Red Dye Using Palladized Bacterial Cellulose in a Reactor
Authors: Vyjayanthi J.P. , Suresh Sumathi
Published: June 2010

Palladized bacterial cellulose was used in the present investigations for the reductive decolorization of drimarene red dye in a rotating catalyst contact reactor (RCCR). Approximately 90% of 100 mg/L of dye was decolorized at pH 2 after 25 minutes of reaction in RCCR using hydrogen as the reducing agent. Scanning electron microscopy and energy dispersive X‐ray spectroscopic analyses suggested irreversible impregnation of nano‐sized zero‐valent‐form palladium (Pd0) deposits within the bacterial cellulose fibrils. The kinetics of decolorization remained unaffected by varying initial concentrations of dye and rotational speed of discs in the reactor. The rate of decolorization of dye increased with increasing palladium concentration per unit area of bacterial cellulose and decreasing pH of the reaction phase. UV‐Visible absorption spectroscopy and liquid chromatography‐mass spectroscopy suggested the accumulation of low‐molecular‐weight products, as a result of the cleavage of azo bonds in the dye molecules. Reusability of immobilized palladium is expected to reduce the treatment cost.
Habitat Selection by Prairie Dogs in a Disturbed Landscape at the Edge of Their Geographic Range
Authors: AVILA‐FLORES RAFAEL , BOYCE MARK S. , BOUTIN STAN
Published: June 2010

ABSTRACT Although habitat attributes of black‐tailed prairie dog (Cynomys ludovicianus) colonies have been described for central and northern portions of the species' geographic range, little is known about these associations at the southern edge of this species' distribution. Because high‐quality habitats are expected to be scarcer at the edge of the species' geographic range, different patterns of habitat selection might emerge in these populations. We analyzed habitat selection by black‐tailed prairie dogs in a human‐disturbed mosaic of desert grasslands and shrublands in northwestern Chihuahua, Mexico. We contrasted 151 used and 133 unused habitat units producing 11 case‐control logistic regression models to explain site occupancy by prairie dogs with different combinations of environmental variables. Prairie dogs from Chihuahua occupy sites similar in most respects to sites in more northern regions, although these prairie dogs appear to be more tolerant of increased shrub density and reduced herbage cover. We found that site occupancy was best modeled by positive effects of soil moisture level, cover of forbs, cover of unpalatable vegetation, cover of bare ground, and amount of prairie‐dog colony area within 1 km and by the inverse of altitude, shrub density, herbage height, and amount of hostile habitat within 1 km. The 2 most significant variables were herbage height and shrub density, which might reflect the prominent role that visibility plays in habitat selection by prairie dogs. In contrast, we found weak evidence that human features have significant impacts on site occupancy by prairie dogs. Our results support the prediction that environmental conditions of sites used by prairie dogs in edge regions partially differ from those observed in more northern latitudes. We suggest that reserve managers focus conservation efforts on areas with short vegetation, low density of shrubs, and high herbage cover, conditions that could be promoted by controlled burns, herbage mowing, and mechanical removal of shrubs.
Influence of Summer and Autumn Nutrition on Body Condition and Reproduction in Lactating Mule Deer
Authors: TOLLEFSON TROY N. , SHIPLEY LISA A. , MYERS WOODROW L. , KEISLER DUANE H. , DASGUPTA NAIRANJANA
Published: June 2010

ABSTRACT Recent work suggests that availability and quality of forage in late summer and early autumn, a time when female ungulates face multiple energetic demands, is critical to reproduction in wild ungulates. Therefore, we examined direct links between nutritional quality of diets, body condition, and reproduction of lactating mule deer. Using captive mule deer, we tested the hypothesis that females consuming diets with lower digestible energy (DE; kJ/g) would have lower DE intake rates (DEI; MJ/day), have less body fat and muscle, have later estrus cycles, and have lower pregnancy and twinning rates. Deer fed lower DE diets had lower DEI during summer and autumn. In turn, deer with lower DEI, regardless of diet DE, had lower body mass, body fat, and muscle thickness. When nutritional quality of diets began to decline earlier in the summer, relationships between food quality, DEI, and body condition were stronger. Although DEI did not influence estrus date for deer that became pregnant before 21 December, deer with lower DEI had a lower probability of becoming pregnant and had a lower probability of producing twins. Measures of body condition in October (i.e., body mass, body fat, and muscle depth) predicted pregnancy and twinning rates in mule deer. Serum concentration of hormones leptin and Insulin Growth Factor 1 were not good predictors of body condition or reproduction. These findings suggest that managers concerned with productivity of mule deer populations should consider focusing on assessing and improving quality of forage available in summer and autumn.
Ranking Mahalanobis Distance Models for Predictions of Occupancy From Presence‐Only Data
Authors: GRIFFIN SUZANNE C. , TAPER MARK L. , HOFFMAN ROGER , MILLS L. SCOTT
Published: June 2010

ABSTRACT  The Mahalanobis distance statistic (D2) has emerged as an effective tool to identify suitable habitat from presence data alone, but there has been no mechanism to select among potential habitat covariates. We propose that the best combination of explanatory variables for a D2 model can be identified by ranking potential models based on the proportion of the entire study area that is classified as potentially suitable habitat given that a predetermined proportion of occupied locations are correctly classified. In effect, our approach seeks to minimize errors of commission, or maximize specificity, while holding the omission error rate constant. We used this approach to identify potentially suitable habitat for the Olympic marmot (Marmota olympus), a declining species endemic to Olympic National Park, Washington, USA. We compared models built with all combinations of 11 habitat variables. A 7‐variable model identified 21,143 ha within the park as potentially suitable for marmots, correctly classifying 80% of occupied locations. Additional refinements to the 7‐variable model (e.g., eliminating small patches) further reduced the predicted area to 18,579 ha with little reduction in predictive power. Although we sought a model that would allow field workers to find 80% of Olympic marmot locations, in fact, <3% of 376 occupied locations and <9% of abandoned locations were >100 m from habitat predicted by the final model, suggesting that >90% of occupied marmot habitat could be found by observant workers surveying predicted habitat. The model comparison procedure allowed us to identify the suite of covariates that maximized specificity of our model and, thus, limited the amount of less favorable habitat included in the final prediction area. We expect that by maximizing specificity of models built from presence‐only data, our model comparison procedure will be useful to conservation practitioners planning reintroductions, searching for rare species, or identifying habitat for protection.
Comparing Ground Telemetry and Global Positioning System Methods to Determine Cougar Kill Rates
Authors: RUTH TONI K. , BUOTTE POLLY C. , QUIGLEY HOWARD B.
Published: June 2010

ABSTRACT  We assessed whether use of 2 methods, intensive very high frequency (VHF) radiotelemetry and Global Positioning System (GPS) cluster sampling, yielded similar estimates of cougar (Puma concolor) kill rates in Yellowstone National Park, 1998–2005. We additionally determined biases (underestimation or overestimation of rates) resulting from each method. We used modeling to evaluate what characteristics of clusters best predicted a kill versus no kill and further evaluated which predictor(s) minimized effort and the number of missed kills. We conducted 16 VHF ground predation sequences resulting in 37 kill intervals (KIs) and 21 GPS sequences resulting in 84 KIs on 6 solitary adult females, 4 maternal females, and 5 adult males. Kill rates (days/kill and biomass [kg] killed/day) did not differ between VHF and GPS predation sampling methods for maternal females, solitary adult females, and adult males. Sixteen of 142 (11.3%) kills detected via GPS clusters were missed through VHF ground‐based sampling, and the kill rate was underestimated by an average of 5.2 (95% CI = 3.8–6.6) days/kill over all cougar social classes. Five of 142 (3.5%) kills identified by GPS cluster sampling were incorrectly identified as the focal individual's kill from scavenging, and the kill rate was overestimated within the adult male social class by an average of 5.8 (95% CI = 3.0–8.5) days/ungulate kill. The number of nights (locations between 2000 hours and 0500 hours) a cougar spent at a cluster was the most efficient variable at predicting predation, minimizing the missed kills, and minimizing number of extra clusters that needed to be searched. In Yellowstone National Park, where competing carnivores displaced cougars from their kills, it was necessary to search extra sites where a kill may not have been present to ensure we did not miss small, ungulate prey kills or kills with displacement. Using predictions from models to assign unvisited clusters as no kill, small prey kill, or large prey kill can bias downward the number of kills a cougar made and bias upward kills made by competitors that displace cougars or scavenge cougar kills. Our findings emphasize that field visitation is crucial in determining displacement and scavenging events that can result in biases when using GPS cluster methods in multicarnivore systems.
White‐Headed Woodpecker Nesting Ecology After Wildfire
Authors: WIGHTMAN CATHERINE S. , SAAB VICTORIA A. , FORRISTAL CHRIS , MELLEN‐MCLEAN KIM , MARKUS AMY
Published: June 2010

ABSTRACT Within forests susceptible to wildfire and insect infestations, land managers need to balance dead tree removal and habitat requirements for wildlife species associated with snags. We used Mahalanobis distance methods to develop predictive models of white‐headed woodpecker (Picoides albolarvatus) nesting habitat in postfire ponderosa pine (Pinus ponderosa)‐dominated landscapes on the Fremont‐Winema National Forests in south central Oregon, USA. The 1‐km radius (314 ha) surrounding 45 nest sites was open‐canopied before fire and a mosaic of burn severities after wildfire. The 1‐ha surrounding nests of white‐headed woodpeckers had fewer live trees per hectare and more decayed and larger diameter snags than at non‐nest sites. The leading cause of nest failure seemed to be predation. Habitat and abiotic features were not associated with nest survival. High daily survival rates and little variation within habitat features among nest locations suggest white‐headed woodpeckers were consistently selecting high suitability habitats. Management activities that open the forest canopy and create conditions conducive to a mosaic burn pattern will probably provide suitable white‐headed woodpecker nesting habitat after wildfire. When making postfire salvage logging decisions, we suggest that retention of larger, more decayed snags will provide nesting habitat in recently burned forests.
Science and Values Influencing Predator Control for Alaska Moose Management
Authors: BOERTJE RODNEY D. , KEECH MARK A. , PARAGI THOMAS F.
Published: June 2010

ABSTRACT  We encourage informed and transparent decision‐making processes concerning the recently expanded programs in Alaska, USA, to reduce predation on moose (Alces alces). The decision whether to implement predator control ultimately concerns what society should value; therefore, policymakers, not objective biologists, play a leadership role. From a management and scientific standpoint, biological support for these predator‐control programs requires convincing evidence that 1) predators kill substantial numbers of moose that would otherwise mostly live and be available for harvest, 2) low predation can facilitate reliably higher harvests of moose, 3) given less predation, habitats can sustain more moose and be protected from too many moose, and 4) sustainable populations of Alaska's brown bears (Ursus arctos), black bears (Ursus americanus), and wolves (Canis lupus) will exist in and out of control areas. We reviewed 10 moose mortality studies, 36 case histories, 10 manipulative studies, 15 moose nutrition studies, and 3 recent successful uses of nutrition‐based management to harvest excess female moose. Results of these studies support application of long‐term, substantial predator control for increasing yield of moose in these simple systems where moose are a primary prey of 3 effective predators. We found no substantive, contradictory results in these systems. However, to identify and administer feasible moose population objectives, recently established moose nutritional indices must be monitored, and regulatory bodies must accept nutrition‐based management. In addition, the efficacy of techniques to reduce bear predation requires further study. Predicting precise results of predator control on subsequent harvest of moose will continue to be problematic because of a diversity of changing interactions among biological, environmental, and practical factors. In Alaska, the governor has the prerogative to influence regulations on predator control by appointing members to the Board of Game. At least annually, the Board of Game hears a wide spectrum of public opinions opposing and favoring predator control. We summarized these opinions as well as the societal and cultural values and expectations that are often the primary basis for debates. Advocates on both sides of the debate suggest they hold the higher conservation ethic, and both sides provide biased science. We recommend a more constructive and credible dialogue that focuses openly on values rather than on biased science and fabricated conspiracies. To be credible and to add substance in this divisive political arena, biologists must be well informed and provide complete information in an unbiased and respectful manner without exaggeration.
Novel Scavenger Removal Trials Increase Wind Turbine—Caused Avian Fatality Estimates
Authors: SMALLWOOD K. SHAWN , BELL DOUGLAS A. , SNYDER SARA A. , DIDONATO JOSEPH E.
Published: June 2010

ABSTRACT  For comparing impacts of bird and bat collisions with wind turbines, investigators estimate fatalities/megawatt (MW) of rated capacity/year, based on periodic carcass searches and trials used to estimate carcasses not found due to scavenger removal and searcher error. However, scavenger trials typically place ≥10 carcasses at once within small areas already supplying scavengers with carcasses deposited by wind turbines, so scavengers may be unable to process and remove all placed carcasses. To avoid scavenger swamping, which might bias fatality estimates low, we placed only 1–5 bird carcasses at a time amongst 52 wind turbines in our 249.7‐ha study area, each carcass monitored by a motion‐activated camera. Scavengers removed 50 of 63 carcasses, averaging 4.45 days to the first scavenging event. By 15 days, which corresponded with most of our search intervals, scavengers removed 0% and 67% of large‐bodied raptors placed in winter and summer, respectively, and 15% and 71% of small birds placed in winter and summer, respectively. By 15 days, scavengers removed 42% of large raptors as compared to 15% removed in conventional trials, and scavengers removed 62% of small birds as compared to 52% removed in conventional trials. Based on our methodology, we estimated mean annual fatalities caused by 21.9 MW of wind turbines in Vasco Caves Regional Preserve (within Altamont Pass Wind Resource Area, California, USA) were 13 red‐tailed hawks (Buteo jamaicensis), 12 barn owls (Tyto alba), 18 burrowing owls (Athene cunicularia), 48 total raptors, and 99 total birds. Compared to fatality rates estimated from conventional scavenger trials, our estimates were nearly 3 times higher for red‐tailed hawk and barn owl, 68% higher for all raptors, and 67% higher for all birds. We also found that deaths/gigawatt‐hour of power generation declined quickly with increasing capacity factor among wind turbines, indicating collision hazard increased with greater intermittency in turbine operations. Fatality monitoring at wind turbines might improve by using scavenger removal trials free of scavenger swamping and by relating fatality rates to power output data in addition to rated capacity (i.e., turbine size). The resulting greater precision in mortality estimates will assist wildlife managers to assess wind farm impacts and to more accurately measure the effects of mitigation measures implemented to lessen those impacts.
A Modified Track Tube for Detecting Beach Mice
Authors: LOGGINS RONALD E. , GORE JEFFERY A. , BROWN LAURINDA L. , SLABY LAURA A. , LEONE ERIN H.
Published: June 2010

ABSTRACT Standard track tube designs are ineffective for long‐term monitoring of beach mice (Peromyscus polionotus) largely because of blowing sand and rain in the coastal dune habitat. We developed a novel track tube design with the tube elevated, capped on one end, and covered on the other end with a short 90° elbow tube. We tested this tube design against 2 other designs (elevated and ground). Our elevated 90° elbow track tubes detected beach mouse tracks more often and they were disturbed less frequently than elevated or ground tubes. Elevated 90° elbow track tubes are a practical means for managers to conduct long‐term monitoring of beach mouse populations.
Using Advancements in Cable‐Trapping to Overcome Barriers to Furbearer Management in the United States
Authors: VANTASSEL STEPHEN M. , HILLER TIM L. , POWELL KELLY D. J. , HYGNSTROM SCOTT E.
Published: June 2010

ABSTRACT  Harvest of furbearers through trapping has been challenged by anti‐trapping organizations for centuries, with organizational goals often including prohibition of all forms of trapping. Challenges to trapping may also include dissention among state wildlife agencies, pro‐hunting organizations, and pro‐trapping organizations. Despite recent efforts by anti‐trapping organizations and occasional dissention among consumptive‐use groups, national trends in snaring regulations included less restrictive regulations through time. This positive trend may offer opportunities for state wildlife agencies and pro‐trapping organizations to enhance the public image of trapping, increase recruitment of trappers, and reverse the increasing trend of wildlife damage and associated costs. We offer support and suggestions to state wildlife agencies and pro‐trapping organizations to help achieve these goals, with their partnership likely having a synergistic effect. Although we attempt to illuminate approaches for increasing support for trapping within the constraints of the cultural norms of the United States, we hope our approaches are useful to and promote dialogue in other jurisdictions experiencing similar problems.
Deer Carrying Capacity in Mid‐Rotation Pine Plantations of Mississippi
Authors: IGLAY RAYMOND B. , JONES PHILLIP D. , MILLER DARREN A. , DEMARAIS STEPHEN , LEOPOLD BRUCE D. , BURGER L. WES
Published: June 2010

ABSTRACT  Herbicides, commonly used for vegetation management in intensively managed pine (Pinus spp.) forests of the southeastern United States, with and without fire, may alter availability of quality forage for white‐tailed deer (Odocoileus virginianus; deer), an economically and socially important game species in North America. Because greater forage quality yields greater deer growth and productivity and intensively managed pine forests are common in the southeastern United States, forest managers would benefit from an understanding of fire and herbicide effects on forage availability to improve habitat conditions for deer. Therefore, we evaluated independent and combined effects of fire and herbicide (i.e., imazapyr) on forage biomass and deer nutritional carrying capacity (CC) on land owned and managed by Weyerhaeuser NR Company in east‐central Mississippi, USA. We used a randomized complete block design of 6 pine plantations (blocks) divided into 4 10‐ha treatment plots to each of which we randomly assigned a treatment (burn‐only, herbicide‐only, burn + herbicide, and control). We estimated biomass (kg/ha) of moderate‐ and high‐use deer forage plants during July of 1999–2008, then estimated CC for diets to support either body maintenance (6% crude protein) or lactation (14% crude protein) with a nutritional constraints model. Herbaceous forages responded positively to fire and herbicide application. In most years, CC estimates for maintenance and lactation were greater in burn + herbicide than in controls. Maintenance‐level CC was always greater in burn + herbicide than in controls, except at 1 year posttreatment. Burn + herbicide was 2.6–8.3 times greater (x̄ = 4.0) than control for lactation‐level CC in 8 of 9 years posttreatment. We recommend fire and selective herbicides to increase high‐quality deer forage in mid‐rotation, intensively managed pine plantations.
Living on the Edge: Viability of Moose in Northeastern Minnesota
Authors: LENARZ MARK S. , FIEBERG JOHN , SCHRAGE MICHAEL W. , EDWARDS ANDREW J.
Published: June 2010

ABSTRACT North temperate species on the southern edge of their distribution are especially at risk to climate‐induced changes. One such species is the moose (Alces alces), whose continental United States distribution is restricted to northern states or northern portions of the Rocky Mountain cordillera. We used a series of matrix models to evaluate the demographic implications of estimated survival and reproduction schedules for a moose population in northeastern Minnesota, USA, between 2002 and 2008. We used data from a telemetry study to calculate adult survival rates and estimated calf survival and fertility of adult females by using results of helicopter surveys. Estimated age‐ and year‐specific survival rates showed a sinusoidal temporal pattern during our study and were lower for younger and old‐aged animals. Estimates of annual adult survival (when assumed to be constant for ages >1.7 yr old) ranged from 0.74 to 0.85. Annual calf survival averaged 0.40, and the annual ratio of calves born to radiocollared females averaged 0.78. Point estimates for the finite rate of increase (λ) from yearly matrices ranged from 0.67 to 0.98 during our 6‐year study, indicative of a long‐term declining population. Assuming each matrix to be equally likely to occur in the future, we estimated a long‐term stochastic growth rate of 0.85. Even if heat stress is not responsible for current levels of survival, continuation of this growth rate will ultimately result in a northward shift of the southern edge of moose distribution. Population growth rate, and its uncertainty, was most sensitive to changes in estimated adult survival rates. The relative importance of adult survival to population viability has important implications for harvest of large herbivores and the collection of information on wildlife fertility.
Development of a New Absorption-Demixing Heat Transformer: Cycle and Working Mixture Optimization
Authors: Noubli Halima , Alonso Dominique , Renaudin Viviane , Cachot Thierry
Published: June 2010

The recovery of waste heat generated by many processes is one of the measures to reduce energy consumption. Heat pump is a machine which upgrades waste heat to make it useful. This study focuses on the development of an Absorption Demixing Heat Transformer (ADHT), a new type of Absorption Heat Transformer (AHT). An ADHT, using a working mixture exhibiting a miscibility gap at low temperature, can use low temperature heat to produce useful thermal energy at a higher temperature. The distillation column used to separate the components of the working mixture used in classical AHT is replaced by a settler where the separation is energetically free. The aim of this study is the cycle and working mixture optimization to find suitable working mixtures for an industrial use (targeted temperature lift (?Ti) ~40°C). In previous studies, the machine was operated successfully with the n-heptane/N,N dimethyl formamide (DMF) mixture, but has not led to a significant temperature lift (less than 8°C). A simulation code, written in FORTRAN 95, is developed to evaluate the performance of ADHT (temperature lift and thermal yield). This code includes a simplified thermodynamic model to represent the properties (enthalpy, equilibrium phase, etc.) of the mixture. The influence on the performances of operating parameters (column feed ratio and number of theoretical stages, etc.) is studied. The main parameters affecting the performance of ADHT are identified. The influence on the performances of each individual thermo-physical property of the mixture components (heat capacity, enthalpy of vaporization, etc.) is also studied. Key properties are identified including the enthalpy of vaporisation of components. A pilot ADHT unit will be constructed in order to prove the reliability of the machine.
Optimization of a Marine Medium for Augmented Biosurfactant Production
Authors: Sivapathasekaran C. , Mukherjee Soumen , Sen Ramkrishna
Published: June 2010

Marine Bacillus circulans used in this study produced 2.58 g L-1 of biosurfactant when grown in unoptimized modified marine medium (MMM). The biosurfactant production was enhanced by optimizing the critical components of the MMM using statistical modeling based response surface methodology (RSM). From the results of single-factor-at-a-time optimization experiments; glucose, urea, SrCl2 and MgSO4 were identified as critical components that affected biosurfactant production significantly. In RSM optimization, experiments were done based on the 24 full factorial central composite design to generate responses, which were used to fit the quadratic polynomial model. Statistical analyses of the data of model fitting were done by using Design Expert version 7.0. The optimum values obtained for the test components for the maximum predicted biosurfactant concentration of 3.04 g L-1 were found to be (in g L-1): glucose = 35.5, urea = 1.23, SrCl2 = 0.11 and MgSO4=0.53. Validation experiments using the optimum values of the critical media components showed that the biosurfactant yield was enhanced to 3.01 g L-1, which was in close agreement with the model prediction. Thus, the biosurfactant production was increased by 17% in the optimized MMM, when compared to that in unoptimized medium.
Non-Ideal Flow in Liquid-Solid Fixed Beds of Irregular-Shaped Particles: A Critical Review
Authors: Inglezakis Vassilis J
Published: June 2010

Available data and correlations for non ideal flow in liquid-solid fixed beds are summarized and reviewed with focus on irregular-shaped particles as packing material. The reason is that in many industrial applications (adsorption, ion exchange, catalysis, etc.) the particles used are of irregular shape while the vast majority of available data on dispersion and non ideal flow is on non-porous spherical or other ordered-shaped particles (saddles, rings, cylinders, tablets, etc.). In the same time, dispersion plays an important part, for example, in reactant and product transport in packed bed reactors, in adsorption, leaching, etc. In the present review all available correlations and data for liquid-solid fixed beds packed with irregular-shaped particles are collected for the prediction of the dispersion coefficients over a wide range of practical values particle Reynolds number. For the current review, 198 experimental points used and 6 Ped  Rep correlations are presented, all derived for irregular-shaped particles.