The incidence and significance of ingested lead pellet poisoning in British Wildfowl

The objective of this study was to assess the extent of lead pellet ingestion by British wildfowl, particularly ducks and geese, and to examine regional variations. The gizzard contents of 2445 shot and 238 found-dead birds were examined, and lead concentrations were determined for 1620 liver and 1841 wing bone samples. In addition, X-ray photographs and blood samples were taken from live-caught birds. Ingested lead pellets were found in 3·2% of the birds examined. For a range of species, including pink-footed goose, white-fronted goose, barnacle goose, wigeon, teal, pintail, shoveler, scaup and moorhen, recorded incidences were either very low or zero. Relatively high incidences were noted for swans, greylag goose (7·1% of shot birds), gadwall (11·8%), mallard (4·2%), pochard (10·9%), tufted duck (11·7%) and goldeneye (6·7%). Most ingested pellets originated from shotguns, though anglers' split shot were found in one pochard and four mute swans. A marked seasonal variation in the extent of pellet ingestion was noted for mallard, with a peak in September, and evidence of high levels immediately before and after the shooting season. Pellet ingestion by mallard was found to be of widespread occurrence, though with considerable variation in recorded incidence from place to place. Inland areas tended to be worse, with the highest incidences recorded for birds shot at flight ponds and other freshwater bodies. Six per cent of mallard shot at inland sites contained ingested pellets, compared with 2·6% of those collected from coastal areas. The observed extent of pellet ingestion in British mallard is calculated directly to cause the death of at least 8000 each winter. Some measures that could be taken to alleviate the lead-poisoning problem in Britain are discussed, and progress of the USA's non-toxic pellet programme is examined.     

Incidence of embedded shotgun pellets in Bewick’s swans Cygnus columbianus bewickii and whooper swans Cygnus cygnus wintering in the UK

The migratory whooper swans (Cygnus cygnus) and Bewick’s swans (Cygnus columbianus bewickii) have been protected by national and international legislation throughout their migratory ranges since the mid 20th century, yet illegal shooting of both species still occurs. X-rays taken of wild caught swans at several sites in the UK were inspected to determine: (1) the incidence of embedded pellets in live birds, (2) inter-specific differences in the level of illegal shooting, and (3) trends in the prevalence of shot-in pellets between the 1970s and the 2000s. A significantly higher proportion of Bewick’s swans (31.2%) contained shot-in pellets than whooper swans (13.6%). The likelihood of a bird having been shot increased with its age for both species. The proportion of Bewick’s swans with embedded shot was higher during the 1970s and 1980s than in the 1990s and 2000s but the incidence remains high, with 22.7% of Bewick’s swans X-rayed in the 21st century containing shot. The prevalence of whooper swans with embedded shot did not change significantly over time (14.9% with pellets in the 1980s compared with 13.2% with pellets in the 2000s). As the swans follow different migration routes, the results not only have implications for consistent and effective implementation of legislation, but show that illegal shooting must be addressed at both national and international levels.     

Lead concentrations in bones and feathers of the globally threatened Spanish imperial eagle

Raptors that consume game species may ingest lead fragments or shot embedded in their prey’s flesh. Threatened Spanish imperial eagles Aquila adalberti feed on greylag geese in southern Spain in winter, and often ingest lead shot. We analysed bone and feather samples from 65 Spanish imperial eagle museum specimens collected between 1980 and 1999, to investigate the prevalence of elevated lead concentrations. Four of 34 birds (12%) had very elevated bone lead concentrations. All four birds were young and the concentrations were outliers to the distribution, suggesting probable exposure to lead gunshot. Excluding these elevated lead outliers, bone lead concentrations were correlated with the bird’s age at death. Three of 41 feathers (7%) had elevated lead concentrations, indicative of high exposure during feather formation. When these outliers were omitted, feather lead concentration was correlated with the age of museum specimens, suggesting that a high proportion of feather lead was exogenous, deposited after specimen collection. Therefore, careful interpretation of feather lead concentrations is required to separate endogenous and exogenous lead. We discuss the potential significance of lead poisoning in Spanish imperial eagles and other raptors, and recommend measures for its reduction.     

Maximizing re-introduction success: Assessing the immediate cost of release in a threatened waterfowl

Translocations have become one of the most commonly used tools for biodiversity restoration worldwide, however one out of three re-introduction plans fails to create a viable population or to successfully reinforce the existing one. We used results from the analysis of individual-based information on the re-introduction of a threatened waterfowl species, the crested coots Fulica cristata, to provide guidelines to maximise re-introduction success. We found that about a third of the post-release mortality took place within the first month after release. This immediate ‘cost of release’ in terms of local survival or ‘release risk factor’ seems to be a common feature of re-introduction projects, and it is likely due to the inexperience of captive-born individuals to face the new environment. This hypothesis was supported by the positive association between survival and time spent in the wild Results suggested that coots released between February and May have a slightly higher survival. A joint measure of survival and breeding probabilities indicated that birds released in late winter (February-March) had a higher chance to survive and reproduce compared to birds released later in the year. From an applied perspective our results can be used within an adaptive management framework to determine the optimum period of release, providing substantial support for future decision-making in the management of waterfowl, and other long-term projects of re-introduction of threatened vertebrate species.     

A review of lead poisoning from ammunition sources in terrestrial birds

Poisoning from lead shot in waterbirds has been well documented globally and, in some countries, legislation exists to combat lead toxicosis at wetlands and/or in waterbirds. However, poisoning of terrestrial species such as raptors and upland game birds, while of potential conservation concern, remains largely to be addressed. For several species, shot are not the only ammunition source of lead, as bullet fragments can be ingested from hunter-killed animal carcasses and gut piles left in the field. This review collates the current knowledge of lead poisoning from ammunition in non-waterbirds. Fifty-nine terrestrial bird species have so far been documented to have ingested lead or suffered lead poisoning from ammunition sources, including nine Globally Threatened or Near Threatened species. We discuss the conservation significance of continued lead use, and detail measures needed to combat lead poisoning.     

The effects of lead shot deposition on soils and crops at a clay pigeon shooting site in northern England

Abstract. The impact of lead shot on soils and crops was examined at a clay pigeon shooting site in northern England. Topsoil cores were collected along a 300 m transect from the shooting range, and the numbers of lead shot pellets per soil core, total and 'plant-available'(0.5 m acetic acid extractable) lead concentrations, organic matter content, pH and cation exchange capacity were determined. The number of oilseed rape plants and their stem diameters were recorded in 1 m² quadrats placed at the soil sampling locations. Total and 'plant-available' lead concentrations in the soil were most but plant numbers per m² and mean stem diameters were least in the area of greatest lead shot deposition. Total lead concentrations in the soil commonly exceeded 5000 mg/kg; these are considerably greater than threshold 'trigger' concentrations proposed by the Department of the Environment, above which soils are considered to be contaminated and warrant further investigation. Concentrations of lead in the oilseed rape plants themselves were also largest in the area of most intense lead shot deposition; in root samples the lead concentration exceeded 400 mg/kg. The management and remediation of contaminated soils at the clay pigeon shooting site are discussed.     

Estimating the rate of quasi-extinction of the Australian grey nurse shark (Carcharias taurus) population using deterministic age- and stage-classified models

Grey nurse sharks off the east coast of Australia are listed nationally as “critically endangered” under Schedule 1 of the Environmental Protection and Biodiversity Conservation Act (1999) and may number no more than 300 in New South Wales and southern Queensland waters. They are an inshore, coastal dwelling species and were severely depleted by spearfishing in the 1960s. The population has continued to decline despite protection since 1984. Their life history (long-lived to 25+ years), late maturation (6-8 years), low fecundity (maximum 2 live young biennially), specific habitat requirements, limited inshore distribution, and small population size render them particularly vulnerable to extinction. We estimated the time to quasi-extinction (years elapsed for the population to consist of ?50 females) for the grey nurse shark population off the east coast of Australia based on current estimates of abundance and known anthropogenic rates of mortality. Estimated minimum population size was 300 as of 2002, and minimum anthropogenic mortality assessed from recovered carcasses was 12/year of which 75% were females. We modelled time to quasi-extinction using deterministic age- and stage-classified models for worst-, likely and best-case scenarios. Population size was estimated at 300 (worst), 1000 (likely) and 3000 (best). Anthropogenic mortality was added to the model assuming either all carcasses are being recovered (best), or conservatively, that only 50% are reported (realistic). Depending on model structure, if all carcasses are being reported, quasi-extinction times for worst-, likely and best-case scenarios range from 13 to 16 years, 84-98 years and 289-324 years, respectively. If under-reporting is occurring, time to quasi-extinction ranges from 6 to 8 years, 45-53 years and 173-200 years, respectively. In all scenarios modelled the grey nurse shark population will decline if no further steps are taken to remove anthropogenic sources of mortality. Because estimates of quasi-extinction rate depend on initial population size, and sensitivity analysis revealed that population rate of change was most sensitive to changes in the survival probability of the smallest length classes, obtaining precise estimates of abundance and annual survival of young females is critical.     

Estimating impacts of poison operations on non-target species using mark-recapture analysis and simulation modelling: an example with saddlebacks

Poison operations to control or eradicate exotic mammals are a key component of conservation management in the South Pacific. They also result in by-kill of native species. It is therefore important to develop reliable methods for estimating by-kill and assessing its impact. The North Island saddleback (Philesturnus carunculatus rufusater), a rare New Zealand forest bird, was reintroduced to Mokoia Island in 1992, and 4 years later there was an aerial drop of cereal pellets containing Brodifacoum aimed at eradicating mice. We used mark-recapture analysis on resighting data collected from 1992 to 1997 to estimate the by-kill of saddlebacks attributable to this poison drop. We nominated a set of candidate models to explain the data, and compared these using Akaike's Information Criterion. The analysis showed that saddleback survival was substantially lower than expected in the 6-week interval after the poison drop, taking age, density dependence, season and random variation into account. Taking expected survival rates into account, the probability of an adult being killed was estimated to be 0.45 (95% CI=0.34-0.56), and the probability of a juvenile being killed was estimated to be 0.35 (95% CI=−0.05-0.75). We then used a simulation model developed for the population to assess the longer-term impact of this mortality. While the mortality set back the expansion of the population by 1-2 years, we predicted that the population would have recovered fairly quickly and ultimately reach the same carrying capacity. Mark-recapture analysis permits precise estimates of background survival rates unconfounded by seasonal or random variation.     

Barn owl release in lowland southern England—a twenty-one year study

Twenty-one years of carefully documented barn owl (Tyto alba) study and release in England by the South Midlands Barn Owl Conservation Group (SMBOCG) have necessitated a re-examination of some of the premises on which such release schemes are judged. Fifteen years after the first releases, the number of independently breeding owls (i.e. breeding ‘wild’ or ‘as though wild’) in a 1200 km² study area is still increasing sharply and now far exceeds the number released in any one year, with the rate of increase outstripping the cumulative number of release events. Ringing returns indicate that fledged young dispersed further than adults, and that released adults which immediately deserted their release sites were less likely to survive their first 30 days than those staying in the vicinity of their release, where they could take advantage of supplementary feeding. Artificial feeding at release sites led to pellets containing lower liveweight equivalent of wild-caught prey but higher numbers of fledged young. Otherwise, and importantly, no significant difference in survival, mortality, dispersal, foraging success or breeding success was found between wild/independent owls and various categories of released bird. Availability of field vole habitat was not as important for barn owl breeding success as was found in previous studies, with owls able to replace this species in their diet with the less habitat-specific wood mouse. Evidence is provided that starvation was not as important a cause of mortality as has been proved elsewhere. Although barn owl nests often occurred in extreme close proximity, breeding density had no effect on either foraging or breeding success. The possible genetic consequences of barn owl release in Britain are briefly discussed. Very few barn owl release schemes have attempted to prove that their work is worthwhile, so long-term, well-documented studies such as that presented here are vital in establishing some of the principles involved in releasing barn owls into the wild.     

Fecal pellets from a commensal shrew (Suncus murinus) and a house gecko (Gekkonidae)

Examination of excreta pellets from commensal shrew (Suncus murinus) and tropical house geckos (Gekkonidae) showed several characteristics that were useful in distinguishing these pellets from those of commensal rodents. Commensal shrew pellets contained a large number of embedded insect fragments but no embedded hairs. Each shrew pellet was associated with a distinctive circular stain on the floor or container surface where it was found. Gecko pellets were composed entirely of tightly packed insect fragments with no intervening matrix. In contrast to both shrew and rodent pellets, there was no surface mucous coating. A small white body containing uric acid adhered to one end of each gecko pellet.     

Can natural disturbance-based forestry rescue a declining population of grizzly bears?

Forest managers are increasingly considering historic patterns of natural forest disturbance as a model for forest harvesting and as a coarse-filter ecosystem management tool. We evaluated the long-term (100-year) persistence of a grizzly bear population in Alberta, Canada using forest simulations and habitat modelling. Even with harvesting the same volume of timber, natural disturbance-based forestry resulted in a larger human footprint than traditional two-pass forestry with road densities reaching 1.39 km/km² or more than three times baseline conditions and suggested maximum levels of security for grizzly bears. Because bears favour young forests and edges where food resources are plentiful, a future shift to young forests and more edge habitat resulted in a 20% projected increase in habitat quality and a 10% projected increase in potential carrying capacity. Human-caused mortality risk, however, offset any projected gains in habitat and carrying capacity resulting in the loss of all secure, unprotected territories, regardless of forest harvest method, within the first 20-30 years of simulation. We suggest that natural disturbance-based forestry is an ill-suited management tool for sustaining declining populations of grizzly bears. A management model that explicitly considers road access is more likely to improve grizzly bear population persistence than changing the size of clear-cuts. In fact, large clear cuts might be counter productive for bears since a diversity of habitats within each bear’s home range is more likely to buffer against future uncertainties.     

Successful analysis of gut contents in fungal-feeding oribatid mites by combining body-surface washing and PCR

The feeding habits of soil mesofauna have been a mystery for decades, and depending on the methods used, different degrees of feeding specialisation have been observed. A new way to study the almost unknown feeding habits of soil mesofauna e.g. oribatid mites is to use PCR-based techniques. When applying PCR on these small organisms, the low amount of ingested DNA can cause problems. Even more important is to certify that the amplified DNA does not originate from body-surface contamination. The aim of this study was to analyse if washing of the body surface combined with PCR can be a successful approach when identifying the food ingested by fungivorous mites. The method was developed in a laboratory system where we used the oribatid mite Archegozetes longisetosus as a model organism due to its relatively short life cycle and ease of laboratory culturing. The results demonstrated that surface contamination is a serious problem. Both washing and dissection was needed to remove surface contamination on such small organisms. To get a reliable result the samples also had to contain at least five pooled guts, but preferably ten. This is the first step towards a successful use of PCR-based methods to study natural feeding habits of species most likely contaminated on the body surface. When modified for field conditions, the results obtained by this method have a high potential to answer many questions about the animals feeding habits, and their functional role in the soil.     

Landscape composition affects habitat use and foraging flight distances in breeding European starlings

The recent decline of the European starling in northern Europe has been associated with changes in agricultural land-use. We investigated how agricultural land-use affected starling habitat use and home-range size in a heterogeneous landscape in southern Sweden. Breeding starlings primarily foraged in pastures, a habitat with a high availability of potential food for nestlings. When the availability of pasture close to the nest was low, starlings increased their use of other permanently grass-covered habitats such as field margins and ditches. They also spent a larger proportion of their daytime flying because they visited more distant foraging areas. The further from the nest parents foraged, the higher was the probability that they foraged on a pasture. Feeding frequency of nestlings was negatively related to the distance from the nest parents foraged, but no consequences on nestling survival or growth were found. A lower breeding density at low local availability of pasture may compensate for lack of good foraging habitat. It is suggested that recent changes in the agricultural landscape may have increased the mismatch between the availability of good foraging areas and nest-sites. This might have contributed to the recent population decline of the starling in northern Europe by affecting both foraging habitat quality and flight costs paid by parents during breeding.     

Radio-telemetry increases free-living energy costs in the endangered Takahe Porphyrio mantelli

An assumption of most radio-telemetry studies is that the technique does not affect the behaviour or physiology of the study animal in any important way. However, previous work has shown that radio-tags can elevate the energy costs of activities such as flying and swimming, which may have implications for survival. Using an experimental approach, we assess the impact of tag-bearing on the free-living energy expenditure of a large, relatively inactive, non-swimming bird: based on previous assumptions, it would be expected to be trivial. Daily energy expenditure increased by 8.5% in the flightless Takahe when they were carrying radio-tags. We can rule out several potential sources of elevated living-costs due to tags, and conclude that a greater thermoregulatory effort was likely to be the main factor involved. This increase in energy expenditure could potentially reduce survival in this endangered species, particularly in its montane habitat in winter.     

Combining experimentation and modelling to estimate primary and secondary infections of take-all disease of wheat

Primary and secondary infections are important processes in the epidemiology of plant diseases but can be difficult to quantify experimentally as they often occur at the same time. This problem is all the more challenging in the case of soil-borne diseases, as most processes are hidden in the soil and destructive sampling is time-consuming and makes it difficult to obtain enough observations of disease progress. Here we show how a combination of experimentation and modelling can be used in order to obtain parameters for primary and secondary infections for take-all disease of wheat. First, an experiment with one infected seedling and varying numbers of target seedlings allowed us to estimate the probability of secondary infection by growth of the mycelium through the soil and by growth via the crown of the plant. Several equations were tested for the contact term between susceptible and infectious roots. Secondly, an experiment with primary inoculum placed at different depths allowed us to estimate the probability of primary infection, taking into account secondary infections and the time needed for the roots to reach inoculum depth. In both experiments, the use of simple models was effective in isolating the desired effect from uncontrollable effects occurring in the soil. The probability of secondary infection through the crown was higher than the probability of infection through soil, and the contact term following the mass action or Reed-Frost equation gave a better fit to the data than the other equations tested. The probability of primary infection was higher when inoculum was placed just below the soil surface than when it was placed deeper in the soil.     

无水保活条件下团头鲂生理应激及鱼肉品质的变化

为探讨无水保活对团头鲂生理应激和肌肉品质的影响,该文研究了团头鲂无水保活所需的较佳条件,测定了未处理(对照)、无水和恢复3种状态下团头鲂的血液生化以及鱼肉成分、持水力、新鲜度、质构和游离氨基酸等品质指标。结果表明:团头鲂无水保活的较佳生活水温为(14.8±0.2)℃(冬季),以2℃/h降至休眠温度2℃,充氧包装后在2℃无水保活14 h,在当季暂养水温中((14.8±0.2)℃)恢复24 h后存活率为100%;无水保活14 h后,血液中皮质醇和乳酸浓度、谷草转氨酶和谷丙转氨酶活力显著高于未处理(对照)(P0.05),血糖浓度和碱性磷酸酶活性明显低于未处理值(P0.05),当季暂养水温恢复24 h后,基本都恢复至未处理组值,但谷草转氨酶仍明显高于未处理组值(P0.05);低温无水环境对团头鲂鱼肉中蛋白质和脂肪含量、新鲜度和持水力无影响,但鱼肉的硬度和咀嚼性明显下降(P0.05),鱼肉游离氨基酸中丝氨酸(Ser)、谷氨酸(Glu)、甘氨酸(Gly)、缬氨酸(Val)和精氨酸(Arg)等含量显著升高(P0.05),异亮氨酸(Ile)、亮氨酸(Leu)、酪氨酸(Tyr)和苯丙氨酸(Phe)在无水保活过程中无明显变化,当季暂养水温恢复后却显著高于未处理组水平(P0.05)。因此,团头鲂无水保活中产生的应激反应在恢复24 h后基本消除,且无水保活对鱼肉的食用品质影响较小。该研究结果为无水保活在淡水鱼活鱼运输中的应用提供参考。     

Distribution and Degradation of Fresh Water Plastic Particles Along the Beaches of Lake Huron, Canada

Resistivity of plastic litter to chemical weathering, mechanical erosion, and biological degradation poses a critical environmental threat. Plastic debris has increased in abundance over the past several decades along shorelines and at sea, where organisms mistake small particles including plastic pellets as a potential food supply. These pellets have been shown to adsorb persistent organic pollutants such as PCBs, which may endanger the organism and become ingested higher in the food chain. Although several studies have been conducted to determine the amount and effects of plastics pollution in marine environments, relatively little is known concerning fresh water plastics pollution. This study represents the first detailed examination of the distribution, types, and physical and chemical degradation processes of plastic particles in a fresh water setting. In conducting field surveys along the shoreline of Lake Huron, Canada, we were able to ascertain that the total number of pellets over multiple sampling localities comprise 94% of plastic debris. The majority of the pellets were found proximal to an industrial sector along the southeastern margin of the lake and their abundance steadily decreased northward, following the dominant lake current patterns. Laboratory analyses using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy indicate predominant mechanical abrasion textures, including grooves, gauges, pits, and flakes, and less common chemical weathering features such as linear and crescentic fractures that developed from shrinkage during subaerial exposure. The predominant type of plastic, polyethylene, appears to be much more resistant to chemical weathering than polypropylene, as indicated by oxidation peaks on FTIR spectra suggesting that polypropylene degrades more readily under natural conditions on freshwater beaches.     

Conservation status and limiting factors in the endangered population of Egyptian vulture (Neophron percnopterus) in the Canary Islands

Egyptian vulture populations have decreased sharply in the Western Palearctic; island populations are almost extinct in the Mediterranean and the Macaronesian regions. In the Canary archipelago, the species only survives in the islands of Fuerteventura and Lanzarote. During 1998-2001 we examined population parameters and evaluated some potential limiting factors for this isolated and sedentary population. The total population (breeding and non-breeding birds) was monitored annually. In addition, 26 fledglings and 33 immatures (<6 years old) and adult birds were captured for individual marking with plastic rings. Twenty-three/twenty-four occupied territories were located in the island and the total population estimated at around 130 birds. Breeding success was lower than recorded elsewhere in the species' distribution area: only 0.43 fledglings/pair/year were produced. Adult (>6 years old birds) and immature annual survival rates were similar, around 90%. Adult survival was lower than expected as territorial birds seem more susceptible to poisoning. Immature survival could be favoured by the existence of regular feeding places. Casualties from power lines was the main cause of mortality (12 cases during the study period). Blood sampling revealed high frequencies of lead poisoning: 13.5 and 2.7% of individuals showed sub-clinical and clinical intoxication levels, respectively, probably caused by the ingestion of lead shot. Priority conservation measures should be directed to reduce electrocution risks, illegal poisoning, and lead contamination. Population reinforcement with birds coming from other populations is not recommended as previous information reveals morphological and genetic differentiation of Canarian Egyptian vultures compared with continental populations.     

Demography and conservation of the Tristan albatross Diomedea [exulans] dabbenena

The Tristan albatross Diomedea [exulans] dabbenena is the third rarest albatross species, with a breeding population of around 1500 pairs almost totally restricted to Gough Island in the Tristan da Cunha group, central South Atlantic. During January 2000, the entire breeding population of Gough was surveyed for the first time since 1956, and 2400 incubating pairs were counted. An analysis of the areas that are likely to have been surveyed most accurately in the past suggests that the population has decreased by around 28% over 46 years. The number of large chicks counted over three successive seasons (1999-2001) was highly variable (range 318-1129). The average count over this period (705 chicks) is less than counts made in 1979 (792) and 1982 (798). A total of 656 chicks were counted in September 2001, giving an island breeding success of just 27.3%. However, breeding success varied considerably in different areas of the island, ranging from 17.6 to 68.0%. During the 2001 season most breeding failures were of large chicks, and over 4 years where data were available, 75% of breeding failures occurred during the chick period. Predation by introduced house mice Mus musculus is the most likely cause of chick mortality. In a small study population, birds began breeding at an average age of 9.7 years and annual adult survival from 1985 to 2001 was 92.6% (SE=1.6%). Both breeding success and adult survival estimates are low in comparison with other Diomedea species and population modelling predicts a population decreasing at an annual rate of 2.9-5.3%. Further research is needed urgently to assess whether breeding success is typical, and to confirm that mouse predation is the cause of chick mortality. The low productivity of this species will compound the negative impacts of longline fishing mortality, which are likely to be reducing adult and juvenile survival.     

Evaluating effects of deforestation, hunting, and El Niño events on a threatened lemur

Madagascar ranks as one of the world’s top extinction hotspots because of its high endemism and high rate of habitat degradation. Global climate phenomena such as El Niño Southern Oscillations may have confounding impacts on the island’s threatened biota but these effects are less well known. We performed a demographic study of Propithecus edwardsi, a lemur inhabiting the eastern rainforest of Madagascar, to evaluate the impact of deforestation, hunting, and El Niño on its population and to re-evaluate present endangerment categorization under the IUCN. Over 18 years of demographic data, including survival and fecundity rates were used to parameterize a stochastic population model structured with three stage classes (yearlings, juveniles, and adults). Results demonstrate that hunting and deforestation are the most significant threats to the population. Analysis of several plausible scenarios and combinations of threat revealed that a 50% population decline within three generations was very likely, supporting current IUCN classification. However, the analysis also suggested that changing global cycles may pose further threat. The average fecundity of lemurs was over 65% lower during El Niño years. While not as severe as deforestation or hunting, if El Niño events remain at the current high frequency there may be negative consequences for the population. We suggest that it is most critical for this species continued survival to create more protected areas, not only to thwart hunting and deforestation, but also to give this endangered lemur a better chance to recover from and adapt to altered climate cycles in the future.