Natural Research Ltd.

Aberdeenshire, United Kingdom

Natural Research Ltd.

Aberdeenshire, United Kingdom
Time filter
Source Type

Vasilakis D.P.,University of Patras | Whitfield D.P.,Natural Research Ltd | Kati V.,University of Patras
PLoS ONE | Year: 2017

Wind farm development can combat climate change but may also threaten bird populations' persistence through collision with wind turbine blades if such development is improperly planned strategically and cumulatively. Such improper planning may often occur. Numerous wind farms are planned in a region hosting the only cinereous vulture population in southeastern Europe. We combined range use modelling and a Collision Risk Model (CRM) to predict the cumulative collision mortality for cinereous vulture under all operating and proposed wind farms. Four different vulture avoidance rates were considered in the CRM. Cumulative collision mortality was expected to be eight to ten times greater in the future (proposed and operating wind farms) than currently (operating wind farms), equivalent to 44% of the current population (103 individuals) if all proposals are authorized (2744 MW). Even under the most optimistic scenario whereby authorized proposals will not collectively exceed the national target for wind harnessing in the study area (960 MW), cumulative collision mortality would still be high (17% of current population) and likely lead to population extinction. Under any wind farm proposal scenario, over 92% of expected deaths would occur in the core area of the population, further implying inadequate spatial planning and implementation of relevant European legislation with scant regard for governmental obligations to protect key species. On the basis of a sensitivity map we derive a spatially explicit solution that could meet the national target of wind harnessing with a minimum conservation cost of less than 1% population loss providing that the population mortality (5.2%) caused by the operating wind farms in the core area would be totally mitigated. Under other scenarios, the vulture population would probably be at serious risk of extinction. Our 'win-win' approach is appropriate to other potential conflicts where wind farms may cumulatively threaten wildlife populations. © 2017 Vasilakis et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Hoy S.R.,University of Aberdeen | Millon A.,CNRS Mediterranean Institute for Biodiversity and Ecology Marine and Continental | Petty S.J.,University of Aberdeen | Whitfield D.P.,Natural Research Ltd | Lambin X.,University of Aberdeen
Journal of Animal Ecology | Year: 2016

Deciphering the causes of variation in reproductive success is a fundamental issue in ecology, as the number of offspring produced is an important driver of individual fitness and population dynamics. Little is known, however, about how different factors interact to drive variation in reproduction, such as whether an individual's response to extrinsic conditions (e.g. food availability or predation) varies according to its intrinsic attributes (e.g. age, previous allocation of resources towards reproduction). We used 29 years of reproductive data from marked female tawny owls and natural variation in food availability (field vole) and predator abundance (northern goshawk) to quantify the extent to which extrinsic and intrinsic factors interact to influence owl reproductive traits (breeding propensity, clutch size and nest abandonment). Extrinsic and intrinsic factors appeared to interact to affect breeding propensity (which accounted for 83% of the variation in owl reproductive success). Breeding propensity increased with vole density, although increasing goshawk abundance reduced the strength of this relationship. Owls became slightly more likely to breed as they aged, although this was only apparent for individuals who had fledged chicks the year before. Owls laid larger clutches when food was more abundant. When owls were breeding in territories less exposed to goshawk predation, 99·5% of all breeding attempts reached the fledging stage. In contrast, the probability of breeding attempts reaching the fledging stage in territories more exposed to goshawk predation depended on the amount of resources an owl had already allocated towards reproduction (averaging 87·7% for owls with clutches of 1–2 eggs compared to 97·5% for owls with clutches of 4–6 eggs). Overall, our results suggested that changes in extrinsic conditions (predominantly food availability, but also predator abundance) had the greatest influence on owl reproduction. In response to deteriorating extrinsic conditions (fewer voles and more goshawks), owls appeared to breed more frequently, but allocated fewer resources per breeding attempt. However, intrinsic attributes also appeared to have a relatively small influence on how an individual responded to variation in extrinsic conditions, which indicates that owl reproductive decisions were shaped by a complex series of extrinsic and intrinsic trade-offs. © 2016 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

Terraube J.,Natural Research Ltd. | Terraube J.,Institute Investigacio en Recursos Cinegeticos IREC | Mougeot F.,CSIC - Estación Experimental De Zonas Áridas | Cornulier T.,University of Aberdeen | And 2 more authors.
Diversity and Distributions | Year: 2012

Aim: To identify the migration routes and wintering grounds of the core populations of the near-threatened pallid harrier, Circus macrourus, and highlight conservation needs associated with these phases of the annual cycle. Location: Breeding area: north-central Kazakhstan; Wintering areas: Sahel belt (Burkina Faso to Ethiopia) and north-west India. Methods: We used ring recovery data from Kazakhstan and satellite tracking data from 2007 to 2008 on six adults breeding in north-central Kazakhstan to determine migration routes and locate wintering areas. In addition, one first-year male was tagged in winter 2007-2008 in India. Results: Data evidenced an intercontinental migratory divide within the core pallid harrier population, with birds wintering in either Africa or India. The six individuals tagged in north-central Kazakhstan followed a similar route (west of the Caspian Sea and Middle East) towards east Africa, before spreading along the Sahel belt to winter either in Sudan, Ethiopia, Niger or Burkina Faso. Spring migration followed a shorter, more direct route, with marked interindividual variation. The bird tagged in India spent the summer in central Kazakhstan. Half of the signal losses (either because of failure or bird mortality) occurred on the wintering areas and during migration. Main conclusions: Our study shows that birds from one breeding area may winter over a strikingly broad range within and across continents. The intercontinental migratory divide of pallid harriers suggests the coexistence of distinct migratory strategies within the core breeding population, a characteristic most likely shared by a number of threatened species in central Asia. Conservation strategies for species like the pallid harrier, therefore, require considering very large spatial scales with possibly area-specific conservation issues. We highlight urgent research priorities to effectively inform the conservation of these species. © 2011 Blackwell Publishing Ltd.

Lopez-Lopez P.,University of Valencia | Lopez-Lopez P.,Biodiversity Conservation Group | Ferrer M.,Biodiversity Conservation Group | Madero A.,Consejeria de Medio Ambiente | And 2 more authors.
PLoS ONE | Year: 2011

Background: Man-induced mortality of birds caused by electrocution with poorly-designed pylons and power lines has been reported to be an important mortality factor that could become a major cause of population decline of one of the world rarest raptors, the Spanish imperial eagle (Aquila adalberti). Consequently it has resulted in an increasing awareness of this problem amongst land managers and the public at large, as well as increased research into the distribution of electrocution events and likely mitigation measures. Methodology/Principal Findings: We provide information of how mitigation measures implemented on a regional level under the conservation program of the Spanish imperial eagle have resulted in a positive shift of demographic trends in Spain. A 35 years temporal data set (1974-2009) on mortality of Spanish imperial eagle was recorded, including population censuses, and data on electrocution and non-electrocution of birds. Additional information was obtained from 32 radio-tracked young eagles and specific field surveys. Data were divided into two periods, before and after the approval of a regional regulation of power line design in 1990 which established mandatory rules aimed at minimizing or eliminating the negative impacts of power lines facilities on avian populations. Our results show how population size and the average annual percentage of population change have increased between the two periods, whereas the number of electrocuted birds has been reduced in spite of the continuous growing of the wiring network. Conclusions: Our results demonstrate that solving bird electrocution is an affordable problem if political interest is shown and financial investment is made. The combination of an adequate spatial planning with a sustainable development of human infrastructures will contribute positively to the conservation of the Spanish imperial eagle and may underpin population growth and range expansion, with positive side effects on other endangered species. © 2011 López-López et al.

Garcia J.T.,Institute Investigacion en Recursos Cinegeticos IREC CSIC UCLM JCCM | Alda F.,Institute Investigacion en Recursos Cinegeticos IREC CSIC UCLM JCCM | Terraube J.,Institute Investigacion en Recursos Cinegeticos IREC CSIC UCLM JCCM | Terraube J.,Natural Research Ltd | And 5 more authors.
BMC Evolutionary Biology | Year: 2011

Background: Environmental preferences and past climatic changes may determine the length of time during which a species range has contracted or expanded from refugia, thereby influencing levels of genetic diversification. Connectivity among populations of steppe-associated taxa might have been maximal during the long glacial periods, and interrupted only during the shorter interglacial phases, potentially resulting in low levels of genetic differentiation among populations. We investigated this hypothesis by exploring patterns of genetic diversity, past demography and gene flow in a raptor species characteristic of steppes, the Montagu's harrier (Circus pygargus), using mitochondrial DNA data from 13 breeding populations and two wintering populations. Results: Consistent with our hypothesis, Montagu's harrier has relatively low genetic variation at the mitochondrial DNA. The highest levels of genetic diversity were found in coastal Spain, France and central Asia. These areas, which were open landscapes during the Holocene, may have acted as refugia when most of the European continent was covered by forests. We found significant genetic differentiation between two population groups, at the SW and NE parts of the species' range. Two events of past population growth were detected, and occurred ca. 7500-5500 and ca. 3500-1000 years BP in the SW and NE part of the range respectively. These events were likely associated with vegetation shifts caused by climate and human-induced changes during the Holocene. Conclusions: The relative genetic homogeneity observed across populations of this steppe raptor may be explained by a short isolation time, relatively recent population expansions and a relaxed philopatry. We highlight the importance of considering the consequence of isolation and colonization processes in order to better understand the evolutionary history of steppe species. © 2011Garcia et al; licensee BioMed Central Ltd.

Terraube J.,Natural Research Ltd | Terraube J.,Institute Of Investigacion En Recursos Cinegeticos | Arroyo B.,Natural Research Ltd | Arroyo B.,Institute Of Investigacion En Recursos Cinegeticos | And 3 more authors.
Oikos | Year: 2011

Specialist species, using a narrow range of resources, are predicted to be more efficient when foraging on their preferred food than generalist species consuming a wider range of foods. We tested whether the foraging efficiency of the pallid harrier Circus macrourus, a vole specialist, and of sympatric Montagu's harriers C. pygargus, a closely related generalist, differed in relation to inter-annual variations in vole abundance over five years (including two peak- one intermediate and two low vole abundance years). We show that the hunting parameters of pallid harriers strongly varied with vole abundance (higher encounter rates, capture rates and proportion of successful strikes in high than intermediate and low vole abundance years, respectively), whereas Montagu's harriers showed stable capture rates and hunting success (proportion of strikes that were successful), irrespective of vole abundance. Encounter rates and capture rates were higher for pallid than for Montagu's harriers when voles were abundant, but lower when voles were scarce. The hunting success of pallid harriers was also lower than that of Montagu's harriers when voles were scarce, and when they had to target alternative preys, in particular birds. Overall, estimated biomass intake rate was 40% higher for pallid harriers than for Montagu's harriers when voles were abundant, but 50% lower when voles were scarce. Our results indicate that specialists predators, like pallid harriers, which evolve specific adaptations or breeding strategies, do better when their preferred prey is abundant, but may face a cost of specialisation, being not efficient enough when their preferred prey is scarce. These results have broader implications for understanding why specialist predators are, in general, more vulnerable than generalists, and for predicting how specialists can cope with rapid environmental changes affecting the abundance or predictability of their preferred resources. © 2011 The Authors.

Terraube J.,Natural Research Ltd. | Terraube J.,Institute Investigacion en Recursos Cinegeticos | Arroyo B.,Institute Investigacion en Recursos Cinegeticos
Biodiversity and Conservation | Year: 2011

Factors linked with intraspecific variation in trophic diversity are still poorly understood in generalist species like the Montagu's harrier (Circus pygargus) but may have important implications for conservation management at a wide scale. We described geographic patterns of Montagu's harrier diet across Eurasia, gathering diet data from 30 studies in 41 areas from 11 countries. We grouped prey as invertebrates, reptiles, small mammals, large mammals, eggs, small birds and large birds, and calculated the contribution of each prey type to the diet (as % biomass) and Shannon's Diversity Index for each study site. We analysed qualitative estimates of prey abundance in relation to latitude and longitude, then diet composition in relation to habitat of the study area and prey abundance estimates. Diet diversity of Montagu's harriers increased from north to south, while abundance of all prey groups other than small mammals showed the opposite trends. Agricultural areas in northern latitudes seemed to hold high densities of small mammals, but low densities of alternative prey. Overall, birds were the main prey in most of Montagu's harrier's distribution range, although the relative importance of each prey type in the diet was significantly explained by its local abundance and habitat, confirming the opportunistic foraging strategy of this raptor species. Consumption of mammals was an exception to this trend, being negatively associated with the abundance of alternative prey, suggesting that this prey is not preferred. Trophic diversity in this species could be influenced by land-use changes through variations in the abundance and availability of prey, which could impact its population dynamics. This may be particularly important for northern populations of Montagu's harriers breeding in agricultural habitats, where trophic diversity is already low. © 2011 Springer Science+Business Media B.V.

Christie D.,Kessels Ecology | Urquhart B.,Natural Research Ltd
New Zealand Journal of Zoology | Year: 2015

A new spreadsheet is presented, to be used as part of the Band model for estimating potential avian mortality due to wind turbine strike. The spreadsheet extends the Band collision risk spreadsheet by allowing for oblique approach angles and wind speed. The differences in the results between this new spreadsheet and the standard Band spreadsheet are given for two species, the white-tailed eagle Haliaeetus albicilla and the South Island pied oystercatcher Haematopus finschi, chosen for their contrasting sizes and flight characteristics. Under more representative conditions, the true risk for large birds is shown to be substantially greater than that calculated by the Band spreadsheet. Examples of how to use the new spreadsheet with bird survey and wind data are given. © 2015 The Royal Society of New Zealand

Separation of animals and humans using a protective set-back distance (Minimum Approaching Distance) is a popular tool for conservation managers to promote wildlife-human coexistence. In several cases, Minimum Approaching Distance is based on how animals respond to an approaching human, using Flight InitiationDistance orAlert Distance. Alert Distance, when animals first show increased vigilance to an approaching human, is considered the best basis for Minimum ApproachingDistance because animals have time to adapt their response. Alert Distance is frequently difficult or impossible to measure in practice, however, especially in breeding birds.Using a study of breedingWood Sandpipers Tringa glareola, in which Alert Distance could not be measured directly, we tested three possible solutions to this dilemma. Alarm Call Distance did not appear to provide a useful substitute for Alert Distance because sandpipers probably alarm called after they had first detected a human. Published predictions of Alert Distance using bodymass also failed to provide realistic estimates of disturbance distances in Wood Sandpipers. The "fixed-slope rule", which predicts that Alert Distance is about double Flight Initiation Distance, was not supported by relationships between AlarmCallDistance and Flight InitiationDistance, but was supported by a relationship between an estimated AlertDistance surrogate and Flight InitiationDistance. This suggests that this rulemay have general utility in predicting Alert Distance when only the more readily measured Flight Initiation Distancemetric is known.AMinimum ApproachingDistance (protective buffer zone) of 160 m is recommended for breedingWood Sandpipers.

Gavashelishvili A.,Ilia State University | McGrady M.,Natural Research Ltd | Ghasabian M.,Armenian National Academy of Sciences | Bildstein K.L.,Acopian Center for Conservation Learning
Bird Study | Year: 2012

Capsule Juvenile and immature Cinereous Vultures from the Caucasus move large distances across undeveloped open-dry habitats in response to snowfall or high summer temperatures. Aim To study local and long-range movements of Cinereous Vulture (Aegypius monachus), and investigate the influence of environmental variables on spatial and temporal distributions of the species on a large scale. Methods We use 4-year-long location data from 6 juvenile Cinereous Vultures fitted with satellite-received transmitters to track their movements and obtain habitat suitability models. Results A few months after fledging, Cinereous Vultures may migrate from the Caucasus as far south as the Arabian Peninsula. Their movements are concentrated in undeveloped open-dry habitats. High temperatures push the vultures to higher latitudes and altitudes, while reverse seasonal movements are triggered by the extent of snow cover. Conclusions Our study shows the importance of the Arabian Peninsula and Iran as wintering areas for Cinereous Vultures. Long-distance movements by immature cinereous vultures are determined by climate seasonality, and in light of climate-warming scenarios for the next 100 years, there might be a shift in timing of the onset of the species seasonal movements and a change in the duration and geography of its wintering and summering. © 2012 Copyright British Trust for Ornithology.

Loading Natural Research Ltd. collaborators
Loading Natural Research Ltd. collaborators