Traffic noise affects communication behaviour in a breeding anuran, Hyla arborea

Modern human societies generate new patterns of noise that may affect acoustic communication in many animal species. Whilst animals have evolved several mechanisms to cope with natural background noise, the rapid increase of anthropogenic alteration of acoustic environment could challenge the potential for adjustments of communicative systems. Because acoustic communication is involved in crucial behaviours, noise pollution can be particularly detrimental in affecting breeding success or survival. I investigated the impact of traffic noise on acoustic communication in a tree frog by way of an experimental approach using noise playback. Traffic noise triggered a decrease of the males’ calling activity, with males being more affected when noise amplitude increased. Additionally, the males’ social situation (calling in chorus versus alone) exerted a strong influence on sensitiveness to noise. Males were only weakly affected by noise pollution when calling in a chorus situation, probably because they were more stimulated and because traffic noise emergence was lower. Moreover results showed that in response to noise playback, males are not able to adjust their temporal or frequency call structures to increase efficiency of the information transfer. Understanding species’ ability to adapt their communicative systems to cope with human-made noise constitutes an important contribution to wildlife conservation.     

Habitat selection of the Eurasian woodcock in winter in relation to earthworms availability

The Eurasian woodcock (Scolopax rusticola) is a game species experiencing high hunting pressure, long-term modifications of its habitats, and with questions regarding its current conservation status. Winter is a season of highest concentration of birds and hunting pressure but woodcock precise habitat requirements are poorly known. It is crucial to assess threats and to develop sustainable management options for the conservation of woodcock populations. During three consecutive winters, we monitored 65 individual woodcocks fitted with radio-tags in Brittany, France. Habitat selection was analysed using GIS and compositional analysis, in relation to vegetation types, soil variables (humus types) and the abundance of their main prey (earthworms). Woodcocks used different habitats diurnally and nocturnally, generally preferring areas with high earthworm biomass. Diurnal habitat selection in forests was associated with humus type (preference for mulls, rich in earthworms) and dense shrub strata (better protection). Hedges with a high density of trees and shrub were also important habitat. At night, grazed meadows were the preferred habitat, containing five times higher biomass of earthworms compared to cultivated fields. Sustainable management of populations requires protection and management of habitats that incorporates food and cover. Forestry practices should preserve rich humus types and coppices by choosing tree species that ameliorate the soil and soil tilling. Changes in landscapes and intensive agricultural practices are current threats to woodcock populations: destruction of hedges, decrease of permanent grazed meadows, impoverishment of soils fauna biomasses from ploughing and chemical applications. However, woodcocks may benefit from the recent development of set-asides, grass field-borders and simplified farm practices (no-tillage and direct sowing).     

Heavy reliance on surrogate species and historical data may confound estimates of the sustainability of hunting in Papua New Guinea

Birds are among the most widely studied organisms on earth and represent an important indicator group for learning about the effects of climate change – particularly in regard to the effects of climate change on tropical ecosystems. In this review, we assess the potential impacts of climate change on tropical birds and discuss the factors that affect species’ ability to adapt and survive the impending alterations in habitat availability. Tropical mountain birds, species without access to higher elevations, coastal forest birds, and restricted-range species are especially vulnerable. Some birds may be especially susceptible to increased rainfall seasonality and to extreme weather events, such as heat waves, cold spells, and tropical cyclones. Birds that experience limited temperature variation and have low basal metabolic rates will be the most prone to the physiological effects of warming temperatures and heat waves. Mostly unknown species’ interactions, indirect effects, and synergies of climate change with other threats, such as habitat loss, emerging diseases, invasive species, and hunting will exacerbate the effects of climate change on tropical birds. In some models habitat loss can increase bird extinctions caused by climate change by 50%. 3.5 °C surface warming by the year 2100 may result in 600–900 extinctions of land bird species, 89% of which occur in the tropics. Depending on the amount of future habitat loss, each degree of surface warming could lead to approximately 100–500 additional bird extinctions. Protected areas will be more important than ever, but they need to be designed with climate change in mind. Although 92% of currently protected areas are likely to become climatically unsuitable in a century, for example only 7 or 8 priority species’ preferred climatic envelopes are projected to be entirely lost from the African Important Bird Area network. Networks of protected areas need to incorporate extensive topographical diversity, cover wide elevational ranges, have high connectivity, and integrate human-dominated landscapes into conservation schemes. Most tropical bird species vulnerable to climate change are not currently considered threatened with extinction, often due to lack of knowledge; systematically and regularly gathering information on the ecology, and current and future distributions of these species is an urgent priority. Locally based, long-term tropical bird monitoring and conservation programs based on adaptive management are essential to help protect birds against climate change.     

The importance of chemical communication studies to mammalian conservation biology: A review

The relevance of chemical communication to mammalian conservation is not often the focus of scientific investigation. Our review identifies and discusses ten key areas in which the study of chemical communication aids conservation behaviour. Articles (n = 140) were revealed, most were concerned with population monitoring (22.50%), reducing human-wildlife conflicts (18.93), influencing habitat selection (18.57%), increasing welfare of captive animals (12.86%), encouraging captive breeding (12.86%), reducing predation (5.71%), and increasing the success of release programmes (5.00%). Few articles (<4%) were found relating olfactory studies to health status of wild populations, reducing hybridization or as indication of pollution. A growing number of articles are addressing how olfactory studies may aid conservation, but more rigorous experimental testing and manipulations are required. The vast majority of studies linking olfaction with conservation involved the population monitoring of wild carnivores. We suggest that animal behavioural studies and manipulations of chemical communication can have significant impacts on conservation in these areas, which should be further developed to generate practical applications. Areas of future study include chemical communication of aquatic mammalian species, the transfer of olfactory cues under water, and the identification of genetic markers that may link ‘personality’ with olfactory responses. Linking olfactory studies to fitness, either on an individual or population scale, particularly in a wider ecological context is more likely to increase conservation value. Animal translocations and reintroduction programmes may offer a means to do this and could be an important area to direct future studies.     

Correlates of extinction risk and hunting pressure in gamebirds (Galliformes)

The 284 species of Galliformes are a highly threatened group of birds subject to direct exploitation for food, sport and cultural practices. The impact of hunting is often assumed to contribute to the high percentage of species (26.4%) listed as threatened with extinction in the IUCN Red List. We take a macroecological approach to examine the anthropogenic and ecological correlates of extinction risk and hunting pressure using linear and stepwise regression. Independent contrasts are analysed, as well as raw species data, to control for the potential confounding influence of phylogenetic trends. Extinction risk is found to be predicted both by the ecological factors considered (e.g., latitudinal range, body mass, elevational range, habitat use) and secondarily by human factors (e.g., human population density, total calorie intake, composition of diet). Hunting pressure itself is also predicted well for the threatened species by several of the anthropogenic and ecological variables. The study demonstrates that human variables can be used successfully to predict extinction risk, and represent an improvement upon methods which examine ecological variables alone. Furthermore, we show that individual threats can be explored using similar techniques, providing a more detailed insight into the processes leading to extinction. As applied to the Galliformes, both approaches provide evidence supporting the hypothesis that hunting pressure has contributed to the high proportion of threatened species in this group, and thus reinforce the case for urgent measures to reduce the impacts of direct exploitation upon these birds.     

Grizzly bear response to human development and activities in the Bow River Watershed, Alberta, Canada

Few studies have reported the effects of multiple human activities on grizzly bears, Ursus arctos. We document the degree of grizzly bear response to various human developments as a function of multiple interacting variables based on observed median distances to roads, trails and development features in a landscape where human presence is widespread. Female grizzly bears remained further than males from paved roads regardless of habitat quality or time of day. Males were found closer to paved roads when within or adjacent to high quality habitat and during the period of least human activity. The combination of traffic volume and highway configuration, however, overrides a bear’s attraction to high quality habitats for high-speed, high-volume, highways. Avoidance of busy transportation corridors was strongest in the adult segment of the population. Bears were found closer to trails during the human inactive period when within high quality habitat and further from trails when distant to high quality habitat. Our data indicated an inverse relationship between the sexes in response to vehicles and traffic noise compared to the response to human settlement and encountering people. Female bears were found further away than males in relation to vehicles and traffic noise, yet found closer than males to human settlement and places where people may be encountered. Those males that were more willing to exploit high quality habitat near roads, did so at night and where hiding cover was present. Adult females were the most risk-averse cohort, choosing to avoid humans instead of seeking out high quality habitats. Adult female grizzly bears were influenced most by human activities and development. Management agencies must maintain access to high quality habitat, especially for adult females, and create new opportunities to support the reproductive potential of the population.     

Effects of anthropogenic land use on forest birds and butterflies in Subic Bay, Philippines

Despite the loss of 83% of native forests in the Philippines, little is known on the effects of this massive habitat loss and degradation on its forest biotas. This is a cause for concern because of the threat posed to the country’s large number of endemic taxa. To investigate the impacts of anthropogenic disturbance, forest birds and butterflies were surveyed in closed and open canopy forests, as well as suburban, rural and urban areas within the Subic Bay Watershed Reserve and Olongapo City in western Luzon. Measures of forest species richness and population densities for both taxa were similar in the two forest types, but showed different patterns in the other habitats. Indirect gradient analysis showed that forest bird species were positively correlated with vegetation variables (i.e., canopy cover, tree density, height to inversion and ground cover), while forest butterflies were not strongly correlated to any of the measured habitat variables. Community composition of birds in forests was distinct from those in modified habitats, while butterfly communities were more similar. A simulation showed that canopy cover of 60% or higher was required by 24 of the 26 bird species that were sensitive to canopy loss. Endemicity and nesting strata were the significant predictors of vulnerability to habitat disturbance for birds, while endemicity and larval hostplant specificity were significant for butterflies. Both taxa were negatively affected by anthropogenic disturbance but may respond to different components in the habitat (i.e., structure and resources), and thus cannot be used as surrogates of each other. Conservation of forests with contiguous canopy cover should be prioritized, and more ecological research is needed to improve the knowledge on the effects of disturbance on Philippine biodiversity.     

Land use and conservation value for forest birds in Central Sulawesi (Indonesia)

Unprecedented deforestation is currently underway in Southeast Asia. Since this trend is likely to continue, it is critical to determine the value of human-modified habitats (e.g., mixed-rural habitat) for conserving the regional native forest avifauna. The impacts of ongoing deforestation on the highly endemic avifauna (33%) of Sulawesi (Indonesia) are poorly understood. We sampled birds in primary and secondary forests in the Lore Lindu National Park in central Sulawesi, as well as the surrounding plantation and mixed-rural habitats. Species richness, species density and population density of forest birds showed a consistent decreasing trend in the following order: primary forests > secondary forests > mixed-rural habitat > plantations. Although primary forests contained the highest proportion (85%) of a total of 34 forest species recorded from our point count surveys, 40-yr old secondary forests and the mixed-rural habitat showed high conservation potential, containing 82% and 76% of the forest species, respectively. Plantations recorded only 32% of the forest bird species. Fifteen forest species had the highest abundance in primary forests, while two species had higher abundance outside primary forests. Our simulations revealed that all forest birds that were sensitive to native tree cover could be found in areas with at least 20% continuous native tree cover. Our study shows that although primary forests have the highest conservation value for forest avifauna, the potential of degraded habitats, such as secondary forests and the mixed-rural habitat, for conserving forest species can be enhanced with appropriate land use and management decisions.     

Distribution and relative abundance of peccaries in the Argentine Chaco: associations with human factors

In the Argentine Chaco, the three species of peccaries (Artiodactyla) are likely affected by habitat destruction and hunting, yet basic information on peccary distribution and status in this region is poorly known. This study identifies human factors associated with relative abundance and distribution of each species. Estimation of relative abundance was based on interviews with local hunters, and variables potentially related to distribution and relative abundance of peccaries were estimated for 153 circular sample sites of 10 km diameter in the Argentine Chaco. Peccaries were found in sites of high forest cover, low human density, far from towns and with low density of roads. After accounting for forest cover and other variables, number of settlements was identified as the main variable negatively associated with relative abundance of the three species, which may be a result of local hunting. Density of roads was also negatively associated with presence of chacoan peccaries. Collared peccary seems to be the least susceptible to human perturbations. It was the most widely distributed and found in a wider range of conditions than the other species. Chacoan peccary was relatively rare. Because colonization and development programs are increasing in the region, areas still uninhabited should be protected, construction of roads controlled, and hunting managed.     

Use of highway undercrossings by wildlife in southern California

Roads, especially large highways, can have significant impacts on wildlife movement and survival. This is especially true for wide-ranging species, such as mammalian carnivores. Some of these impacts may be mitigated if wildlife can find and utilize passageways under highways. To determine if underpasses and drainage culverts beneath highways are used by wildlife as movement corridors, we monitored 15 such passages near Los Angeles, California using remotely triggered cameras and gypsum track stations. We found that passages were used by a variety of species, including carnivores, mule deer, small mammals, and reptiles. Many types of undercrossings were utilized, indicating that passages beneath highways, even when not originally designed for wildlife, can provide important safe avenues for animals to cross roads. For mammals of conservation concern, including native carnivores and deer, passage dimensions, surrounding habitat, and the extent of human activity were assessed to determine if these factors influenced passage use by these species. Our results show that while many native mammals used passages beneath highways, the presence of suitable habitat on either side of the passage was a particularly important factor predicting use. For deer and coyotes, passage dimensions were also important and should be considered with the presence of suitable habitat when wildlife passages are planned or evaluated. To increase the likelihood of utilization and to help prevent animals from crossing road surfaces, we suggest that simple improvements such as habitat restoration near crossing points and animal-proof fencing that serves to funnel wildlife to passages, can facilitate animal movement between fragmented habitats that are bisected by roads.     

Allocation of hunting effort by Amazonian smallholders: Implications for conserving wildlife in mixed-use landscapes

Most tropical forest landscapes are modified by humans, but the effects of these changes on rural hunting patterns and hunted vertebrate populations remain poorly understood. We investigated subsistence hunting patterns across a highly heterogeneous landscape mosaic in the Brazilian Amazon, where hunters from three villages had access to primary forest, active and fallow agricultural fields, and active and fallow Eucalyptus plantations. Landscape composition and the areas used by hunters were defined using a remote-sensing approach combined with mapping. We quantified hunting effort accounting for the availability and spatial distribution of each habitat. Overall, 71% of the kills were sourced in primary forest, but hunting in primary forest, which was often combined with other extractive activities (such as Brazil nut harvesting), yielded the lowest catch-per-unit-effort of all habitats. Hunting effort per unit area was highest in fallow fields, followed by primary forest, and both of these habitats were over-represented within village hunting catchments when compared to the composition of the available landscape. Active and fallow fields sourced a limited number of species known to be resilient to hunting, but hunting had additional benefits through crop-raider control. In contrast, hunting pressure in active and fallow plantations was low, despite a high catch-per-unit-effort, presumably because there were limited additional benefits from visiting these habitats. These results indicate that large-scale tree plantation and forest regeneration schemes have limited conservation potential for large vertebrates, as they support few forest specialists and fail to attract hunters away from primary forest.     

Waterfowl-habitat associations during winter in an urban North Atlantic estuary

Coastal habitats near urban centres in North Atlantic estuaries often support substantial numbers of wintering waterfowl, but little is known of the effects of landscape setting and urbanisation on habitat use. We conducted surveys of waterfowl at 32 wintering sites in Narragansett Bay, Rhode Island, to identify characteristics that may influence habitat use. Sites were chosen along a gradient of urbanisation and reflected the dominant habitat types used by waterfowl in the Bay. Mean waterfowl abundance was 206.7 ± 209.5 birds per site, and sites in the inner part of the estuary had higher overall waterfowl abundances (r² = 0.40, p = 0.021). Species richness ranged from 3.2 to 13.0 and decreased with increasing hunting activity (r² = 0.36, p = 0.040). Hunting activity and habitat characteristics (e.g., latitude, shoreline configuration, prey density) explained 13-27% of the variation in waterfowl abundance and species richness among sites, but landscape characteristics (e.g., surrounding residential development, vegetated land, or wetland surrounding the sites and the extent of wetland edge) explained an additional 1-26%. The landscape characteristics extent of adjacent residential development and vegetated upland were the most common variables entering into the models; most species were more abundant at sites with more adjacent vegetated upland and less adjacent residential development. Our results suggest that landscape setting may be influencing the distribution of wintering waterfowl, and should be considered when developing strategies for the conservation for these species in urban North Atlantic estuaries.     

Factors affecting abundance of bowhead whales Balaena mysticetus in the eastern arctic of North America, 1915–1980

The severely depleted bowhead whale Balaena mysticetus has failed to recover from overexploitation during the 18th and 19th centuries in the Eastern Arctic. Although commercial whaling for bowheads ended in this region about 1915, bowhead whaling by native people has continued until recently in parts of the Eastern Arctic. Low-level but persistent hunting by Inuit (Eskimos) may have inhibited bowhead population increase. Two natural mortality factors can be documented—ice entrapment and predation by killer whales Orcinus orca. There is little direct evidence of ice-related mortality but a strong circumstantial argument that ice conditions affect survival. Killer whales are known to prey on most species of large whales, and we believe bowhead whales and right whales Eubalaena glacialis are especially vulnerable. The bowhead's apparent failure to recover in the Eastern Arctic may be due to a combination of continued low-level hunting, habitat instability, and predation. Complete protection from all forms of hunting is necessary to ensure the bowhead's survival. Environmental disturbances due to industrial development in the Arctic may have direct and indirect impact on bowhead habitat and behaviour, creating an urgent need for further study.     

Effects of fuelwood collection and timber harvesting on giant panda habitat use

Timber harvesting and fuelwood collection have dramatically reduced the total amount of forestland around the world, including in China. To understand how timber harvesting and fuelwood collection activities affect use by wildlife, we examined giant panda (Ailuropoda melanoleuca) use within Wolong Nature Reserve, Sichuan Province, southwest China. We evaluated giant panda use of habitat by observing the presence/absence of panda feces in 913 field plots. Newly harvested areas (0-10 years) had the lowest frequency of feces presence (3%), while unharvested forests had the highest (36%). Feces presence is influenced by bamboo cover, overstory and midstory composition, slope, aspect and distance to human activity. Results suggest that timber harvesting and fuelwood collection have important impacts on the use of forested habitats and panda use is reduced for several decades after harvests. However, as the forest regenerates, panda habitat may begin to recover after a period of at least 37 years. This has potential implications for the long-term conservation of panda habitats and suggests that if forestland is maintained via the Natural Forest Conservation Program (China’s logging ban), habitats that were previously harvested may eventually regenerate and increase the potential for the species long-term survival.     

The status of marine turtles in the Egyptian Red Sea

Five species of marine turtle occur in the Egyptian Red Sea and three are recognised by local fishermen: Eretmochelys imbricata (L.), Chelonia mydas (L.), and Dermochelys coriacea (L.). The last named is rarely sighted, and although the other two nest, only Eretmochelys is common; possibly 500 nest yearly, mainly on offshore islands. Both nesting and feeding habitats appear to be extensive for this species, but clutches have an unusually high percentage of yolkless eggs. The significance of this is not understood, but it indicates that the animals are under pressures not experienced in other parts of their range. The small population of Chelonia is probably due to the scarcity of feeding habitat; marine pastures are generally small in area and standing crop. Dermochelys may be rarely sighted because local fishermen infrequently venture into epipelagic waters where this animal is most common, but the available data indicate that the species is a vagrant in Egypt. The enormous swarms of jellyfish that occur in the Egyptian Red Sea evidently do not attract these turtles, although seasonal concentrations of jellyfish are often accompanied by Dermochelys in other seas. Exploitation of turtles, mainly for meat and eggs, is slight, but habitat perturbations are intense from oil pollution and marine explosions. There is a great need for more basic information and rigorous management of the marine environment.     

Diversity and structure of the bird community overwintering in the Himalayan subalpine zone: is conservation compatible with tourism?

In this paper data on the bird community overwintering in the subalpine zone of Sagarmatha National Park (Khumbu Himal area, Nepal) are presented, with particular emphasis on habitat structure and bird-habitat relationships. The impact of land use and management on the conservation of diversity is analysed and discussed. Four habitat types were considered: mixed forest, pure juniper forest, dwarf rhododendron shrubbery and cultivations. Mixed forest supports the richest avifauna, but forest birds are sensitive to over-exploitation of their habitat: bird density, species richness and diversity are significantly lower in heavily utilised forest. Here, the lower density of rhododendrons, firs and birches, together with their younger age, seem to be unattractive to insectivorous gleaners and granivores, which prefer tree- and understorey-rich spots of unutilised forest. Terraced cultivations also are a rich habitat for wintering birds, and traditional cultivations with hedgerows and scattered bushes have a great potential for bird conservation. Juniper woods are important habitats mainly for frugivores, whereas dwarf rhododendron shrubberies support the poorest avifauna. This study emphasises that forest birds and habitats are severely threatened. As deforestation is the consequence of the tourist pressure for fuelwood along the trekking route to Mt. Everest Base Camp, a strict regulation of tourist-related developments is essential to preserve biodiversity and manage land uses within sustainability.     

Environmental monitoring using populations of birds and small mammals: Analyses of sampling effort

Characteristics of bird and small mammal communities can be valuable in monitoring for impacts on specific plots of land. In Utah (USA), significant differences were found among years, habitats and seasons in bird and small mammal abundance, species diversity, and species richness; thus, estimates of these characteristics are consistent and repeatable and can be used for detecting change. Also, bird and small mammal communities are dependent on a wide variety of food resources and habitat characteristics; thus they should reflect a variety of impacts.A comparison is made between two methods of handling bird data from transects: enumeration (individual birds per km) and density (birds per unit area). Correlation between the two was high (r = 0·93). However, density estimates may be necessary to trace an impact to a particular group, guild or species and possibly to its cause.An analysis is made of how much sampling is necessary to make an adequate estimate of the characteristics of bird and small mammal communities. Estimates of bird abundance, species richness and species diversity (from enumeration) may be obtained with three repetitions of 2 km of transect. Three repetitions are also sufficient to estimate abundance of small mammals on 12 by 12 trapping grids. To estimate species richness and species diversity, however, four or more repetitions are needed. Small mammal community characteristics are not well predicted by trapping on transects or small grids except in grids 9 by 9 or larger. These results of sampling effort may only apply to certain habitats but data from bird and small mammal communities should be useful in environmental monitoring at any site.     

Acoustic and behavioural changes by fin whales (Balaenoptera physalus) in response to shipping and airgun noise

Non-lethal behavioural effects of underwater noise in marine mammals are difficult to measure. Here we report acoustic and behavioural changes by fin whales in response to two different types of anthropogenic noise: shipping and airgun noise. Acoustic features of fin whale 20-Hz song notes recorded in the Mediterranean Sea and Northeast Atlantic Ocean were compared for areas with different shipping noise levels, different traffic intensities in the Strait of Gibraltar and during a seismic airgun array survey. In high noise conditions 20-Hz note duration shortened, bandwidth decreased, centre frequency decreased and peak frequency decreased. Similar results were obtained in 20-Hz song notes recorded during a 10-day seismic survey. During the first 72 h of the survey, a steady decrease in song received levels and bearings to singers indicated that whales moved away from the airgun array source and out of our detection area, and this displacement persisted for a time period well beyond the 10-day duration of seismic airgun activity. This study provides evidence that male fin whales from two different subpopulations modify song characteristics under increased background noise conditions, and that under seismic airgun activity conditions they leave an area for an extended period. We hypothesize that fin whale acoustic communication is modified to compensate for increased background noise and that a sensitization process may play a role in the observed temporary displacement. The observed acoustic and behavioural changes of this endangered species are discussed in the context of reproduction success and population survival.     

Bird species abundance–occupancy patterns and sensitivity to forest fragmentation: Implications for conservation in the Brazilian Atlantic forest

Developing a predictive theory for species responses to habitat fragmentation is a large, complex challenge in conservation biology, and meeting this challenge likely requires tailoring predictions to specific habitats and taxa. We evaluate the effects of fragmentation on forest birds living in three distinct forest ecosystems found in Brazilian Atlantic forest: seasonal semi-deciduous forest (SF), mixed rain forest (MF), and dense rain forest (DF). We test the hypotheses that (1) bird species most prevalent in SF (relative to other habitat types) will be least vulnerable to population declines in fragmented SF, and (2) species with stronger affiliations with DF or MF will be relatively more sensitive to fragmentation in SF. Using an exploratory statistical technique called “Rank Occupancy–Abundance Profiles (ROAPs),” we compared distribution and abundance of birds among large “continuous” areas of each forest type, then compared abundances in continuous SF forests with patterns of abundance in small fragments of SF, where edge effects could play a marked role in population dynamics. Overall, 39 species showed substantially lower local abundance, occupancy, or both in SF fragments versus continuous SF. As predicted, a higher proportion of bird species associated with DF appeared sensitive to fragmentation in SF; by contrast, species most abundant in SF and MF were similarly abundant in fragmented SF. Our study demonstrates how quantifying distribution and abundance in diverse habitats may enhance managers’ ability to incorporate species-specific responses to human disturbances in their conservation plans, and points out ways that even small reserves may have significant conservation value.     

Impacts of chronic marine oil pollution and the murre hunt in Newfoundland on thick-billed murre Uria lomvia populations in the eastern Canadian Arctic

We developed a deterministic and stochastic age-based matrix projection population model to assess and quantify the impact of mortality caused by chronic oil pollution and legal hunting on thick-billed murre Uria lomvia populations breeding and wintering in eastern Canada. We calculate the potential population growth rate in the absence of anthropogenic mortality sources using a modeling technique that translates absolute number of birds killed from anthropogenic mortality to potential survival rates in the absence of these anthropogenic impacts. The intrinsic growth rate of the deterministic matrix based on vital rates from Coats Island (λ_d=1.0102), as well as the stochastic growth rate (λ_s=1.0098, 95% C.I. 0.9969-1.0226), matched observed population trends. Hunting mortality reduced population growth rate by 0.020 (0.012-0.039), oiling mortality reduced population growth rate by 0.025 (0.012-0.039). Combined these sources reduced the population growth rate by 0.047 (0.033-0.610). Although thick-billed murre populations are stable or slowly growing in eastern Canada, anthropogenic sources of mortality are reducing the ability of the population to grow, and increase vulnerability in these populations to changes in their environment and other pulse perturbations. Our modeling technique could be used to assess specific anthropogenic impacts on populations where a vital rates and numbers killed are known, but no long-term trend information is available.