Arjun Amar

Understanding and managing conservation conflicts.

Conservation conflicts are increasing and need to be managed to minimise negative impacts on biodiversity, human livelihoods, and human well-being. Here, we explore strategies and case studies that highlight the long-term, dynamic nature of conflicts and the challenges to their management. Conflict management requires parties to recognise problems as shared ones, and engage with clear goals, a transparent evidence base, and an awareness of trade-offs. We hypothesise that conservation outcomes will be less durable when conservationists assert their interests to the detriment of others. Effective conflict management and long-term conservation benefit will be enhanced by better integration of the underpinning social context with the material impacts and evaluation of the efficacy of alternative conflict management approaches.

Evidence for food limitation in the declining hen harrier population on the Orkney Islands, Scotland

The hen harrier (Circus cyaneus) population on the Scottish Orkney Islands has declined dramatically since the end of the 1970s. We postulate that the cause of this decline was due to a reduction in the amount of available prey and predict that if this was the case the population would currently be limited by food. The evidence for this hypothesis is explored by examining the rates at which males deliver prey to their females in relation to breeding performance both among individuals within the declining population and also between this declining population and another, non-declining population in southern Scotland. Breeding performance within the Orkney population was related to male provisioning rates: males that provided more food to their females were more likely to initiate a breeding attempt and there was a tendency for males with the highest provisioning rates to breed with more females. Comparisons between the two populations revealed that harriers on Orkney had a lower breeding performance and also a lower rate of food provision. Changes in agriculture, in particular decreases in rough grazing and increases in sheep densities are thought to be the most likely cause for a reduction in food supply. Conservation measures should be aimed toward increasing the areas of rough grass habitat.

Exploring the relationships between wader declines and current land-use in the British uplands

Capsule Declines of upland waders were associated with habitat cover, forest edge exposure, grouse moor management intensity and crow abundance. Aims To explore whether changes in the abundance of five wader species in the uplands correlate with the three key hypotheses proposed for their declines. Methods Using data from repeat upland bird surveys, we examined at two spatial scales (region and plot) if population changes correlate with vegetation cover, forest edge exposure, grouse moor management intensity or crow abundance. Results For Northern Lapwings Vanellus vanellus and Eurasian Curlews Numenius arquata, there was an association between declines and broad‐scale vegetation cover; declines being greatest on heather‐dominated plots. Exposure to forest edge was associated with declines of European Golden Plovers Pluvialis apricaria and Common Snipe Galinago galinago at the plot scale, and of Northern Lapwings at the regional scale. More intensive grouse moor management was associated with lower declines in Northern Lapwings at both the plot and regional scale, but with greater declines in European Golden Plovers at the plot scale. Northern Lapwings also declined most on plots with the highest Carrion Crow Corvus corone abundance. Conclusion These analyses represent the first attempt to assess empirically the balance of evidence for different broad‐scale land‐use and habitat‐related drivers of upland wader population declines, providing pointers to their respective roles in driving these declines.

Trends in territory occupancy, distribution and density of the Bearded Vulture Gypaetus barbatus meridionalis in southern Africa

Summary T erritory occupancy, distribution and density of the isolated Bearded Vulture Gypaetus barbatus meridionalis population in the Maloti-Drakensberg mountains of southern Africa were assessed between two time periods - former ( 1960–1999) and current ( 2000–2012) - to identify population trends. Overall, 190 territories were recorded of which 109 are currently occupied. The number of occupied breeding territories decreased by a minimum of 32% and a maximum of 51% over the past five decades. Territories located on the periphery of the breeding range were more likely to be abandoned than those in the core. The current population is estimated at a minimum of 352 and a maximum of 390 individuals. The breeding range decreased by 27%, restricting the birds to an estimated area of occupancy of 28,125 km 2 . Breeding densities also decreased by 20%, declining from 4.9 to 3.9 pairs/1,000 km 2 . In both periods, higher densities were recorded in the core of the range. Nests were located about 9.0 km apart, a slight increase from the 7.7 km recorded formerly. Inter-nest distances increased with distance from the core range. Further studies are required to ascertain whether productivity or survival is limiting population growth, and whether anthropo-genic influences are resulting in the abandonment of territories in the periphery of the range and the subsequent decline in number . s

Hen harrier foraging success in relation to land use in Scotland

In the UK, hen harriers (Circus cyaneus) are illegally killed on moorland that is managed for red grouse (Lagopus lagopus scoticus), and they produce fewer young per female on grouse moorland than on either unmanaged moorland or forestry. However, those breeding attempts on grouse moorland that escape nest destruction produce more young than in other land-use classes. One explanation for this difference is that food is more available to harriers on managed moorland than elsewhere. To examine this hypothesis, we compared the capture rates of hunting male harriers on sites across Scotland. Four of these sites were managed for grouse whilst the remaining three consisted of either unmanaged moorland or a mixture of unmanaged moorland and young forestry plantations. We found a significant difference in capture rates, with harriers on managed grouse moorland capturing prey at a greater rate than elsewhere, supporting the idea that prey were more available on grouse moorland. However, there was no difference in strike rates between the land-use classes, suggesting that prey were not necessarily more abundant on grouse moors. Males on unmanaged moorland tended to catch larger prey, though this was insufficient to compensate fully for the reduced capture rates. The improved hunting success on grouse moorland means that this habitat is likely to be more attractive to breeding harriers, thereby increasing the conflict between those interested in maximizing grouse numbers and those interested in conserving rare raptors.

POPULATION TRENDS OF THE FOREST BIRD COMMUNITY ON THE PACIFIC ISLAND OF ROTA, MARIANA ISLANDS

Abstract The Pacific island of Rota is part of the Mariana archipelago, and is located approximately 60 km north of the island of Guam. Two Rota endemics, the Mariana Crow (Corvus kubaryi) and the Rota Bridled White-eye (Zosterops rotensis), have declined dramatically in the last 20 years. We examined trends in abundance of eight terrestrial bird species (six native, two exotic) on Rota between 1982 and 2004, and found that seven of them declined significantly, with five species showing declines >50%. Only Micronesian Starlings (Aplonis opaca) increased in abundance. Declines occurred in species abundant in both forested and open habitats, suggesting that the declines were unlikely to be simply the result of deforestation. While the introduction of the brown tree snake (Boiga irregularis) on Guam caused the collapse of that islands avifauna, we do not believe that Rotas declines are due to the establishment of a snake population. Other, as yet unidentified, agents are likely to be responsible. We suggest that future research into the causative agent(s) of decline focus on the comparatively common declining species, rather than studying small populations of endangered species.

Using spatial analyses of bearded vulture movements in southern Africa to inform wind turbine placement

Summary Concerns over CO2 emissions during energy generation and its effect on climate change have led to increases in the use of renewables, such as wind energy. However, there are also serious environmental concerns over this type of energy production due to its impacts on bats and birds. In southern Africa, bearded vultures have declined by >30% during recent decades. They are now regionally critically endangered with only around 100 active pairs remaining. This species is considered vulnerable to collision with wind turbines which are planned within their southern African range. In this study, we develop habitat use models using data obtained from 21 bearded vultures of different ages fitted with GPS tags from 2009 to 2013. We further refined these models by incorporating flying heights at risk of collision to predict important areas of use that may conflict with wind turbines. Adult and non-adult bearded vultures mostly used areas with high elevations and steep and rugged topography in the core area; adults tended to use areas in relatively close proximity to their nest sites, whereas non-adult birds used areas dispersed over the entire species range and were more likely to fly at risk-height in areas that were less used by adults. Altitudes of fixes of adults and non-adults showed that they spent 55% and 66% of their time, respectively, at heights that placed them at risk of collision. Examining the locations of two proposed wind farms in relation to our model of predicted ‘at risk’ usage suggested poor positioning. Indeed, one of these wind farms was located within the 1% of ‘worst’ (most heavily used) sites for non-adult bearded vultures suggesting that its current location should be reconsidered to reduce the impact on this vulnerable species. Synthesis and applications. We demonstrate the value of habitat use models for identifying intensively used areas, in order to greatly reduce conflicts with developments such as wind turbines. This tool is operable at the scale of regional and national development plans informed by the habitat use of potentially vulnerable species. Such models should provide important supplementary assessments of site-specific development proposals.

Impact of Post-typhoon Hunting on Mariana Fruit Bats (Pteropus mariannus)1

ABSTRACT We examined the abundance of Mariana fruit bats (Pteropus mariannus Desmarest) on the Pacific islands of Rota and Guam before and after a severe typhoon in December 2002. After the typhoon, bat abundance declined by 70% on Rota. On Guam, bat abundance initially increased by ca. 100 individuals (103%), perhaps due to immigration from Rota, but then declined an average of 32% from pretyphoon levels for the remainder of 2003. An increase in post-typhoon hunting pressure represents at least a partial cause for the decline observed on Rota. Interviews with 29 suspected poachers on the island revealed a 34% increase in bat harvest from 2002 to 2003. Hunting of bats is rare on Guam because access to their remaining habitat is restricted by the U.S. military. However, juvenile bats are preyed on by introduced brown tree snakes (Boiga irregularis Bechstein) on Guam to such an extent that little to no within-island recruitment occurs. We therefore suggest that the brief increase and subsequent decrease in bat abundance on Guam was due to interisland movements, a reduction in the source population (Rota), and/or changes in roosting patterns on Guam. Rota is vital to recovery prospects for P. mariannus in the southern Mariana Islands because it holds the only viable population in this part of the archipelago. If the species is not conserved, forest ecosystems may suffer because P. mariannus is almost certainly an important seed disperser and pollinator on these depauparate islands. We recommend that agencies responsible for managing hunted fruit bat populations make special efforts to prevent illegal hunting after severe typhoons.

Fidelity at the frontier: divorce and dispersal in a newly colonized raptor population

Divorce and breeding dispersal are key life history parameters that can be influenced by, and in turn have an influence on, the structure of populations. Variation in these parameters in small populations can potentially play an important role in the colonization of new areas, yet to date there has been little empirical investigation of this process. We studied the circumstances surrounding divorce in a newly established population of black sparrowhawks, Accipiter melanoleucus, on the Cape Peninsula, South Africa over an 11-year period between 2001 and 2012. Divorce was more likely following breeding failure and individuals that divorced and dispersed improved their subsequent breeding success. Territory quality had no influence on the frequency of divorce, and dispersing individuals did not move to territories of higher quality. During the study period the population size increased approximately three-fold, but because the range expanded, nest density did not increase significantly. In the first half of the study (2001–2006), divorce rates were low (4%) compared with rates previously reported for raptors and other birds. In the latter half (2007–2012) divorce rates were 14%. Although there was weak support for a difference in divorce rates between these two periods there was no evidence that divorce rates varied with population size or nesting density. Our results suggest that adaptive hypotheses (‘better option’ or ‘incompatibility’) best explain patterns of divorce in this expanding population and that potential feedbacks between divorce and population processes were unlikely to have played an important role during the growth of this recently established population.

Decline of the Orkney Hen Harrier Circus cyaneus population: do changes to demographic parameters and mating system fit a declining food hypothesis?

Capsule A decline in polygyny and lower secondary female breeding success have reduced male productivity and most likely led to the population decline. Aims To examine whether changes in demographic parameters during a population decline fit with a hypothesis that there has been a reduction in food supplies. Methods We examined changes in the number of young, numbers of successful broods and the size of these broods, produced on west Mainland, Orkney between 1953 and 2000 from ringing returns and original nest records. We also examined the changes in polygyny levels between 1967–74, 1976–81 and 1998–2000. Using more intensive data from 1980–81 and 1998–2000, we examined whether there were any changes in various breeding parameters of primary (monogamous or alpha) females or secondary (beta) females. Results Numbers of young and broods produced have declined dramatically in the west Mainland of Orkney since the end of the 1970s. In the 1970s, an average of 60 chicks fledged each year, whereas an average of only 16 chicks fledged in the 1990s. However, over this same period, the average brood size of successful nests did not change. The percentage of males breeding polygynously decreased from around 75% during 1967–81 to only 17% during 1998–2000, and the breeding success of secondary females also decreased. As a result, productivity of males on Orkney was significantly lower in 1998–2000 than in 1980–81. Conclusions The Hen Harrier population has declined dramatically on Orkney since the end of the 1970s. This was due to a decrease in polygynous breeding and a reduction in the breeding success of secondary females. Changes to demographic parameters were consistent with a hypothesis that the decline was an effect of reduced food availability during the early part of the breeding season during recent years.