214 research outputs found

    Can secondary information inform about population trends of carnivores in Borneo?

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    Effective methods for estimating occurrence and abundance of carnivores are limited and often expensive in labour or equipment. Conducting interviews about wildlife species, including carnivores, is a common tool used in Borneo and throughout Southeast Asia to investigate species distribution and understand their conservation status. Such surveys are appealing because of perceived savings in time and equipment; however, biases in amount of available information, miscommunications about species of interest, and species misidentifi cation can result in errors of unknown magnitude, rendering results of at least some surveys suspect. Hence, it becomes diffi cult to disentangle accurate from inaccurate information. Studies are needed to investigate the variation in effectiveness of interview surveys. Also better guidance is needed to clarify under which conditions secondary surveys can be used with confi dence, and for which particular audience. Until the factors that bias results are identifi ed and, where possible, accounted for, the main use of secondary surveys for carnivores and other diffi cult to identify or rarely encountered species will be to help develop a dialogue between people that reside or work in conservation project areas and the investigators working on such projects. Secondary surveys may also serve as a tool to help identify hypotheses to be addressed in studies with strong experimental designs

    The role of forage availability on diet choice and body condition in American beavers (\u3ci\u3eCastor canadensis\u3c/i\u3e)

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    Forage availability can affect body condition and reproduction in wildlife.Weused terrestrial and aquatic vegetation sampling, stable isotope analysis, and livetrapping to investigate the influence of estimated forage biomass on diet, body condition, and reproduction in American beavers (Castor canadensis) in the Namakan Reservoir, Voyageurs National Park, Minnesota, USA, May 2008–September 2009. Available terrestrial and emergent aquatic forage varied greatly among territories, but floating leaf aquatic forage was low in abundance in all territories. Variation in estimated biomass of available emergent and terrestrial vegetation did not explain variation in respective assimilated diets, but variation in floating leaf vegetation explained 31% of variation in assimilated floating leaf diets. No models using available vegetation explained variation in body condition. Body condition of individual females in spring did not affect kit catch per unit effort, and overwinter body condition of subadults and adults was similar between territories with and without kits. We found no evidence that available aquatic vegetation affected beaver body condition or fitness. Available forage may be above minimum thresholds to detect differences in diet choice or body condition. Other factors such as water level fluctuations or climatic variables may also explain variation in beaver body condition

    Spatiotemporal Dynamics in Identification of Aircraft–Bird Strikes

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    A primary concern for human–wildlife interactions is the potential impacts resulting from wildlife (primarily birds) collisions with aircraft. The identification of species responsible for collisions with aircraft is necessary so that airport management can develop effective strategies to reduce strikes with those species. Of particular importance in developing such strategies is the identification of regional, seasonal, and temporal patterns in collisions with unidentified bird species that may limit the effectiveness of regional habitat management to reduce bird strikes. The authors analyzed 105,529 U.S. civil aviation strike records from 1990 to 2012 in the FAA’s National Wildlife Strike Database to examine patterns of collisions involving unidentified birds. Factors that affected identification were airport certification class, FAA region, mass of struck species, state species richness (if damage was reported), and interactive effects between the last four factors. Identification varied by region and declined with increasing species richness; this identification was greater for general aviation (GA) airports and the mass of struck species, especially when damage was reported. Species identification might be improved by increasing reporting efforts relative to species richness, especially by GA airport managers and operations staff, who may have a higher propensity of reporting bird strikes, and by collecting more fieldbased data on avian populations. The results can provide guidance for the development of airport management and personnel training

    Wildlife at Airports

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    Collisions between aircraft and wildlife (wildlife strikes) are common occurrences across the developed world. Wildlife strikes are not only numerous, but also costly. Estimates suggest that wildlife strikes cost the civil aviation industry in the U.S. up to $625 million annually, and nearly 500 people have been killed in wildlife strikes worldwide. Most wildlife strikes occur in the airport environment: 72 percent of all strikes occur when the aircraft is ≀500 ft (152 m) above ground level, and 41 percent of strikes occur when the aircraft is on the ground during landing or takeoff. Thus, management efforts to reduce wildlife hazards are focused at the airport. There are many techniques used to reduce wildlife hazards at airports, and these usually work best when used in an integrative fashion. Here, we discuss the available data on wildlife strikes with aircraft, summarize legal considerations, explain why wildlife are attracted to airports and how to identify important wildlife attractants, describe commonly-used tools and techniques for reducing wildlife hazards at airports, and explain how airports can enlist the help of professional wildlife biologists to manage wildlife hazards. Effective management of wildlife to reduce strikes, like all types of wildlife damage management, is based on principles from wildlife ecology, physiology, and behavior. Airport biologists should consider how these disciplines interact in the airport context, particularly with an understanding of regulatory guidance, non-wildlife related airport safety priorities, and strike data. This “marriage” of wildlife ecology with aspects of airport operations will aid in discerning how and why animals respond to various mitigation methods (at both the individual and population levels), why and under what conditions some management tools and techniques work better than others, and allow airport biologists to more intelligently direct management efforts

    Spatiotemporal Dynamics in Identification of Aircraft–Bird Strikes

    Get PDF
    A primary concern for human–wildlife interactions is the potential impacts resulting from wildlife (primarily birds) collisions with aircraft. The identification of species responsible for collisions with aircraft is necessary so that airport management can develop effective strategies to reduce strikes with those species. Of particular importance in developing such strategies is the identification of regional, seasonal, and temporal patterns in collisions with unidentified bird species that may limit the effectiveness of regional habitat management to reduce bird strikes. The authors analyzed 105,529 U.S. civil aviation strike records from 1990 to 2012 in the FAA’s National Wildlife Strike Database to examine patterns of collisions involving unidentified birds. Factors that affected identification were airport certification class, FAA region, mass of struck species, state species richness (if damage was reported), and interactive effects between the last four factors. Identification varied by region and declined with increasing species richness; this identification was greater for general aviation (GA) airports and the mass of struck species, especially when damage was reported. Species identification might be improved by increasing reporting efforts relative to species richness, especially by GA airport managers and operations staff, who may have a higher propensity of reporting bird strikes, and by collecting more fieldbased data on avian populations. The results can provide guidance for the development of airport management and personnel training

    Effects of crop type and harvest on nest survival and productivity of dickcissels in semi-natural grasslands

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    Recent focus on climate change and global energy production has increased interest in developing biofuels including perennial native grasses (e.g. switchgrass [Panicum virgatum]) as viable energy commodities while simultaneously maintaining ecosystem function and biodiversity. However, there is limited research examining the effects of biofuel-focused grasslands on grassland bird reproductive success and conservation. In 2011–2013 we studied the effects of vegetation composition and harvest regimens of switchgrass monocultures and native warm-season grass (NWSG) mixtures on nest success, nest density, and productivity for dickcissels (Spiza americana) in Clay Co. MS, USA. There was no effect of vegetation metrics, harvest frequency, or biofuel treatment on nest survival. However, both vegetation composition and harvest frequencies influenced nest density and productivity. Native warm season grasses contained 54–64 times more nests relative to switchgrass treatments, and nest density and productivity were 10% greater in single harvest plots. Our results suggest semi-natural grasslands can balance biofuel production, ecosystem functionality, and conservation so that biofuels offer an opportunity for wildlife conservation rather than a continued threat to grassland birds

    Mineral Licks as a Potential Nidus for Parasite Transmission

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    Discrete landscape features can concentrate animals in time and space, leading to non-random interspecific encounters. These encounters have implications for predator-prey interactions, habitat selection, intraspecific competition, and transmission of parasites and other pathogens. The lifecycle of the parasitic nematode Parelaphostrongylus tenuis requires an intermediate host of a terrestrial gastropod. Natural hosts of P. tenuis are whitetailed deer, and an aberrant host of conservation concern is moose, which are susceptible to high levels of mortality as a naive host to the parasite. Intermediate hosts become infected when P. tenuis larvae are shed in deer feces, then consumed or enter the gastropod through the foot. Incidental (or perhaps intentional) ingestion of infected gastropod intermediate hosts by aberrant or dead-end hosts often results in mortality of that animal. We present photographic evidence depicting a potential mechanism for transmission from infected white-tailed deer to moose, heretofore not examined in the literature. We deployed remote cameras at mineral licks around Grand Portage Indian Reservation in northeastern Minnesota, USA. We observed white-tailed deer defecating at mineral lick sites and geophagous moose at the same sites. We hypothesize that mineral licks may act as a nidus for P. tenuis transmission between deer and moose in this system and call for further research into the potential role of mineral licks in parasite transmission. The Grand Portage Band of Lake Superior Chippewa is a federally recognized Indian tribe in extreme northeastern Minnesota, USA, and proudly exercises its rights to food sovereignty through subsistence hunting and fishing. Mooz (Moose) are a primary subsistence food used by the Anishinaabeg (people) of Grand Portage Band historically and presently. Management for and research on maintaining this moose population as a vital subsistence species thus sets the context for this paper examining potential for disease transmission between whitetailed deer and moose through shared use of mineral licks

    Forage or Biofuel: Assessing Native Warm-season Grass Production among Seed Mixes and Harvest Frequencies within a Wildlife Conservation Framework

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    Native warm-season grasses (NWSG) are gaining merit as biofuel feedstocks for ethanol production with potential for concomitant production of cattle forage and wildlife habitat provision. However, uncertainty continues regarding optimal production approaches for biofuel yield and forage quality within landscapes of competing wildlife conservation objectives. We used a randomized complete block design of 4 treatments to compare vegetation structure, forage and biomass nutrients, and biomass yield between Panicum virgatum (Switchgrass) monocultures and NWSG polycultures harvested once or multiple times near West Point, MS, 2011–2013. Despite taller vegetation and greater biomass in Switchgrass monocultures, NWSG polycultures had greater vegetation structure heterogeneity and plant diversity that could benefit wildlife. However, nutritional content from harvest timings optimal for wildlife conservation (i.e., late dormant season-collected biomass and mid-summer hay samples) demonstrated greater support for biofuel production than quality cattle forage. Future research should consider testing various seed mixes for maximizing biofuel or forage production among multiple site conditions with parallel observations of wildlife use

    Can Secondary Information Inform About Population Trends of Carnivores In Borneo?

    Get PDF
    Effective methods for estimating occurrence and abundance of carnivores are limited and often expensive in labour or equipment. Conducting interviews about wildlife species, including carnivores,is a common tool used in Borneo and throughout Southeast Asia to investigate species distribution and understand their conservation status. Such surveys are appealing because of perceived savings in time and equipment; however, biases in amount of available information, miscommunications about species of interest, and species misidentifi cation can result in errors of unknown magnitude, rendering results of at least some surveys suspect. Hence, it becomes diffi cult to disentangle accurate from inaccurate information. Studies are needed to investigate the variation in effectiveness of interview surveys. Also better guidance is needed to clarify under which conditions secondary surveys can be used with confi dence, and for which particular audience. Until the factors that bias results are identifi ed and, where possible, accounted for, the main use of secondary surveys for carnivores and other diffi cult to identify or rarely encountered species will be to help develop a dialogue between people that reside or work in conservation project areas and the investigators working on such projects. Secondary surveys may also serve as a tool to help identify hypotheses to be addressed in studies with strong experimental designs

    A framework for managing airport grasslands and birds amidst conflicting priorities

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    Management of modern airports is a task beset by conflicting priorities. Airports are vital to the global market economy, but impose costly environmental disturbances including habitat loss, noise, reduced air quality, erosion, introduction of invasive organisms, and polluted storm-water runoff (Blackwell et al. 2009). Airport environments also attract some wildlife hazardous to aviation safety, namely species involved in wildlife-aircraft collisions or ‘strikes’ (ICAO 2001, Blackwell et al. 2009, DeVault et al. 2011). Since 1912 at least 276 human lives have been lost due to bird strikes (Thorpe 2010), and from 1990 to 2010, more than 106 000 bird strikes involving civil aircraft were reported to the US Federal Aviation Administration (FAA; http://wildlife-mitigation. tc.faa.gov/wildlife/). Dolbeer (2006) reported that for strikes resulting in substantial aircraft damage (ICAO 1989), 66% occurred below 152 m altitude and within 1.5 km of a runway for airports servicing piston-powered aircraft only, and within 3 km of a runway for airports servicing turbine-powered aircraft (FAA 2009). Consequently, aviation authorities prioritize human safety over wildlife conservation in management of airport habitats (ICAO 2001, FAA 2009). Despite these problems, airports have been proposed as candidates for biodiversity conservation (Kelly & Allan 2006, Blackwell et al. 2009). For example, Kutschbach- Brohl et al. (2010) report that airport grasslands can provide habitat for a range of arthropod communities (e.g. Lepidoptera), and suggest the possibility of conserving these communities while minimizing provision of prey resources to birds recognized as hazardous to aviation. Moreover, declines in grassland bird populations in Europe and North America due to agricultural intensification and development have focused attention on enhancing quality and quantity of remnant grasslands (Herkert 1994, Vickery et al. 2004), including airport grasslands. In North America, airport properties have been identified as key areas of remnant grasslands important to obligate grassland bird species; species that both nest and forage in grasslands (Vickery et al. 1994, Askins et al. 2007). Airport properties in the contiguous USA include \u3e 330 000 ha of grassland, mostly annually mown areas, constituting 39–50% of airport property (DeVault et al. 2012). However, there is little research specific to airport environments that considers food resources for birds (Bernhardt et al. 2010, Kutschbach-Brohl et al. 2010), how birds perceive and react to predation risk (Baker & Brooks 1981) or disturbance (Kershner & Bollinger 1996), and no adequate assessment of how grassland management might affect strike risk (Blackwell et al. 2009, Martin et al. 2011). In this context, we contend that promoting conservation of obligate grassland birds and managing to reduce bird hazards to aviation safety combines two potentially conflicting objectives in a single management framework. Ecologically based guidance to solve this potential conflict is limited, if not oversimplified. Here, we question the potential use of airports to conserve grassland birds, and assess the challenges in managing airport grasslands in light of current ecological and behavioral frameworks. We consider conditions for conservation of obligate grassland birds on airports, and evidence on the use of airports by frequently struck, grassland birds (both obligate and facultative). We also provide a framework to manage grassland birds at airports, given current information and uncertainty. Because of the availability of strike data via the FAA, our focus is on North America. However, problems associated with bird use of airport grasslands are international (ICAO 2001). Therefore, our ultimate purpose is better to inform current management, but also identify research gaps and establish specific predictions that will guide future studies on the ecological basis of use of airport grasslands by birds
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