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1.
Environ Res ; 227: 115711, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-36940819

RESUMO

Lead exposure is a concern in urban ecosystems, with physiological and behavioral effects well documented in humans. Wildlife inhabiting urban ecosystems are also exposed to lead, yet little work has documented the sublethal effects of lead exposure in urban wildlife. We studied northern mockingbirds (Mimus polyglottos) in three neighborhoods of New Orleans, Louisiana, two with high soil lead and one with low soil lead, to better understand how lead exposure may influence mockingbirds' reproductive biology. We monitored nesting attempts, measured lead concentrations in blood and feathers of nestling mockingbirds, documented egg hatching and nesting success, and assessed rates of sexual promiscuity in relation to neighborhood soil lead levels. We found that nestling mockingbirds' blood and feather lead levels reflected the soil lead levels of their neighborhoods and nestling blood lead levels were similar to those of adult mockingbirds in the same neighborhoods. Nest success, as evaluated by daily nest survival rates, was higher in the lower lead neighborhood. Clutch sizes varied substantially across neighborhoods, but rates of unhatched eggs did not covary with neighborhood lead levels, suggesting that other drivers are influencing variation in clutch sizes and hatching success in urban habitats. At least one-third of nestling mockingbirds were sired by an extra-pair male, and there was no relationship between extra-pair paternity rates and neighborhood lead levels. This study provides insight on how lead contamination may influence reproduction in urban-dwelling wildlife and suggests that nestling birds could serve as useful bioindicators of lead levels in urban neighborhoods.


Assuntos
Passeriformes , Aves Canoras , Animais , Humanos , Masculino , Aves Canoras/fisiologia , Chumbo/análise , Ecossistema , Passeriformes/fisiologia , Reprodução , Animais Selvagens , Solo
2.
Curr Biol ; 32(8): R356-R357, 2022 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-35472420

RESUMO

Bakker et al. use Robinson et al.'s reconstruction of three species of vulture to illustrate how incorrect generation time estimates can yield inaccurate results, underscoring the importance of generation time specification for genetically based reconstructions, especially for comparisons and species of conservation concern.


Assuntos
Falconiformes , Animais , Demografia
3.
Science ; 375(6582): 779-782, 2022 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-35175813

RESUMO

Lead poisoning occurs worldwide in populations of predatory birds, but exposure rates and population impacts are known only from regional studies. We evaluated the lead exposure of 1210 bald and golden eagles from 38 US states across North America, including 620 live eagles. We detected unexpectedly high frequencies of lead poisoning of eagles, both chronic (46 to 47% of bald and golden eagles, as measured in bone) and acute (27 to 33% of bald eagles and 7 to 35% of golden eagles, as measured in liver, blood, and feathers). Frequency of lead poisoning was influenced by age and, for bald eagles, by region and season. Continent-wide demographic modeling suggests that poisoning at this level suppresses population growth rates for bald eagles by 3.8% (95% confidence interval: 2.5%, 5.4%) and for golden eagles by 0.8% (0.7%, 0.9%). Lead poisoning is an underappreciated but important constraint on continent-wide populations of these iconic protected species.

4.
Environ Res ; 189: 109905, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32738723

RESUMO

Wild California condors (Gymnogyps californianus) are frequently exposed to lead via lead-based ammunition ingestion, and recent studies indicate significant exposure to organochlorines (e.g. dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs)) for condors feeding on beach-cast marine mammals. We investigated the influence of contaminant exposure on condor glucocorticoid response through comparisons between wild and captive populations and identification of modifiers of glucocorticoid release in wild condors. We assessed the glucocorticoid response to routine trapping and handling events through measurement of plasma corticosterone and urate glucocorticoid metabolites (GCM). Comparison of peak urate GCM levels showed wild condors exhibited higher responses to handling-associated stressors (2300 ± 1400 ng/g dry wt, average ± SD, n = 27) than captive condors (910 ± 490 ng/g dry wt., n = 6, U = 28, p = 0.003). Multiple linear regression models and an information theoretic approach (AICc) identified several extrinsic variables (e.g., time captive in flight pen before sample collection) that were negatively associated with plasma corticosterone and urate GCM levels in wild condors, which explained ~25% of glucocorticoid variation. When accounting for these extrinsic variables we found that behavioral variables associated with increased lead and organochlorine exposure risk were positively associated with GCM levels, explaining an additional 15% of glucocorticoid variation among wild condors. Days absent from management area, a variable associated with reduced survival attributed to increased lead exposure risk, had a positive influence on plasma corticosterone levels (ß = 53 ± 20 SE) and peak urate GCM levels (ß = 1090 ± 586 SE). Years observed feeding on marine mammals, a variable positively associated with DDE and PCB exposure, positively influenced peak urate GCM (ß = 1100 ± 520 SE) and the magnitude of GCM response (peak GCM - 1st urate GCM) (ß = 1050 ± 500 SE). Our findings suggest that individual propensities for contaminant-associated foraging behaviors predict higher stress-induced glucocorticoid levels in wild condors, and that accounting for variables associated with trapping and handling is essential for assessing the impact of environmental stressors such as contaminants on the condor stress response. As an abnormal glucocorticoid response to stress is associated with reduced reproduction and survival in vertebrates, this work indicates the need for further investigations into the physiological impacts of sub-lethal contaminant exposures in scavenging species worldwide.


Assuntos
Hidrocarbonetos Clorados , Bifenilos Policlorados , Animais , Aves , Diclorodifenil Dicloroetileno
5.
Environ Toxicol Chem ; 38(9): 1988-1994, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31189023

RESUMO

We examined the relationships among tuna consumption, hair mercury levels, and knowledge of mercury exposure risk from tuna consumption in university students that were offered tuna daily at university-run dining halls. Hair total mercury levels in tuna consumers were higher than those in non-tuna consumers (average = 0.466 µg/g ± 0.328 standard deviation [SD], n = 20 vs 0.110 µg/g ± 0.105 SD, n = 33, respectively; p < 0.0001, Mann-Whitney U test), with tuna eaters exhibiting a positive relationship between self-reported tuna consumption at dining halls and hair mercury levels (R2 = 0.868, p < 0.0001, n = 17, linear regression). For all tuna eaters surveyed, more than half (54%) self-reported eating ≥3 tuna meals/wk, potentially exceeding the US Environmental Protection Agency's reference dose for methylmercury of 0.1 µg/kg body weight/d. Seven percent of study participants reported they consumed >20 tuna meals/wk, which was related to hair mercury levels >1 µg/g, a level of concern. Study participants had an overall lack of knowledge and confidence in their knowledge about mercury exposure risk from tuna consumption, with >99% of participants reporting low knowledge and low confidence in survey answers. Our study highlights the importance of education about the risks of tuna consumption, particularly in institutional settings where individuals have unlimited access to tuna products. Environ Toxicol Chem 2019;38:1988-1994. © 2019 SETAC.


Assuntos
Contaminação de Alimentos/análise , Conhecimento , Compostos de Metilmercúrio/análise , Estudantes/psicologia , Atum/metabolismo , Adolescente , Adulto , Animais , Feminino , Cabelo/química , Humanos , Masculino , Compostos de Metilmercúrio/metabolismo , Risco , Inquéritos e Questionários , Universidades , Adulto Jovem
6.
Sci Total Environ ; 654: 593-603, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30447598

RESUMO

Many urban areas have elevated soil lead concentrations due to prior large-scale use of lead in products such as paint and automobile gasoline. This presents a potential problem for the growing numbers of wildlife living in urbanized areas as lead exposure is known to affect multiple physiological systems, including the nervous system, in vertebrate species. In humans and laboratory animals, low-level lead exposure is associated with neurological impairment, but less is known about how lead may affect the behavior of urban wildlife. We focused on the Northern Mockingbird Mimus polyglottos, a common, omnivorous North American songbird, to gain insights into how lead may affect the physiology and behavior of urban wildlife. We predicted that birds living in neighborhoods with high soil lead concentrations would (a) exhibit elevated lead concentrations in their blood and feathers, (b) exhibit lower body condition, (c) exhibit less diverse and consistent vocal repertoires, and (d) behave more aggressively during simulated conspecific territorial intrusions compared to birds living in neighborhoods with lower soil lead concentrations. Controlling for other habitat differences, we found that birds from areas of high soil lead had elevated lead concentrations in blood and feathers, but found no differences in body condition or vocal repertoires. However, birds from high lead areas responded more aggressively during simulated intrusions. These findings indicate that sub-lethal lead exposure may be common among wildlife living in urban areas, and that this exposure is associated with increased aggression. Better understanding of the extent of the relationship between lead exposure and aggression and the consequences this could have for survival and reproduction of wild animals are clear priorities for future work in this and other urban ecosystems.


Assuntos
Agressão/efeitos dos fármacos , Chumbo/metabolismo , Poluentes do Solo/metabolismo , Aves Canoras/fisiologia , Vocalização Animal/efeitos dos fármacos , Animais , Cognição/efeitos dos fármacos , Chumbo/análise , Chumbo/sangue , Masculino , Nova Orleans , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/sangue , Territorialidade
7.
PLoS One ; 13(10): e0205565, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30352070

RESUMO

Vertebrates respond to stressful stimuli with the secretion of glucocorticoid (GC) hormones, such as corticosterone (CORT), and measurements of these hormones in wild species can provide insight into physiological responses to environmental and human-induced stressors. California condors (Gymnogyps californianus) are a critically endangered and intensively managed avian species for which information on GC response to stress is lacking. Here we evaluated a commercially available I125 double antibody radioimmunoassay (RIA) and an enzyme-linked immunosorbent assay (ELISA) kit for measurement of CORT and GC metabolites (GCM) in California condor plasma, urate, and feather samples. The precision and accuracy of the RIA assay outperformed the ELISA for CORT and GCM measurements, and CORT and GCM values were not comparable between the two assays for any sample type. RIA measurements of total CORT in condor plasma collected from 41 condors within 15 minutes of a handling stressor were highly variable (median = 70 ng/mL, range = 1-189 ng/mL) and significantly different between wild and captive condors (p = 0.02, two-tailed t-test, n = 10 wild and 11 captive). Urate GCM levels (median = 620 ng/g dry wt., range = 0.74-7200 ng/g dry wt., n = 216) significantly increased within 2 hr of the acute handling stressor (p = 0.032, n = 11 condors, one-tailed paired t-test), while feather section CORT concentrations (median = 18 pg/mm, range = 6.3-68 ng/g, n = 37) also varied widely within and between feathers. Comparison of multiple regression linear models shows condor age as a significant predictors of plasma CORT levels, while age, sex, and plasma CORT levels predicted GCM levels in urates collected within 30 min of the start of handling. Our findings highlight the need for validation when selecting an immunoassay for use with a new species, and suggest that non-invasively collected urates and feathers hold promise for assessing condor responses to acute or chronic environmental and human-induced stressors.


Assuntos
Aves/metabolismo , Plumas/metabolismo , Glucocorticoides/metabolismo , Estresse Psicológico/metabolismo , Animais , Espécies em Perigo de Extinção , Feminino , Manobra Psicológica , Humanos , Masculino , Estresse Psicológico/etiologia
9.
Ecohealth ; 14(Suppl 1): 92-105, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-26769426

RESUMO

Translocation is an increasingly important tool for managing endangered species, but factors influencing the survival of translocated individuals are not well understood. Here we examine intrinsic and extrinsic drivers of survival for critically endangered California condors (Gymnogyps californianus) whose wild population recovery is reliant upon releases of captively bred stock. We used known fate models and information-theoretic methods to compare the ability of hypothesized covariates, most of which serve as proxies for lead exposure risk, to predict survival rates of condors in California. Our best supported model included the following predictors of survival: age of the recovery program, precipitation, proportion of days observed feeding on proffered carcasses, maximum blood lead concentration over the preceding 18 months, and time since release. We found that as flocks have increased in size and age, condors are increasingly likely to range more widely and less likely to be observed feeding on proffered food, and these "wilder" behaviors were associated with lower survival. After accounting for these behaviors, we found a positive survival trend, which we attribute to ongoing improvements in management. Our findings illustrate that the survival of translocated animals, such as highly social California condors, is influenced by behaviors that change through time.


Assuntos
Espécies em Perigo de Extinção , Chumbo/toxicidade , Aves Predatórias , Animais , California , Chumbo/sangue , Dinâmica Populacional
10.
Environ Sci Technol ; 50(17): 9114-23, 2016 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-27434394

RESUMO

The critically endangered California condor (Gymnogyps californianus) has relied intermittently on dead-stranded marine mammals since the Pleistocene, and this food source is considered important for their current recovery. However, contemporary marine mammals contain persistent organic pollutants that could threaten condor health. We used stable carbon and nitrogen isotope, contaminant, and behavioral data in coastal versus noncoastal condors to quantify contaminant transfer from marine mammals and created simulation models to predict the risk of reproductive impairment for condors from exposure to DDE (p,p'-DDE), a major metabolite of the chlorinated pesticide DDT. Coastal condors had higher whole blood isotope values and mean concentrations of contaminants associated with marine mammals, including mercury (whole blood), sum chlorinated pesticides (comprised of ∼95% DDE) (plasma), sum polychlorinated biphenyls (PCBs) (plasma), and sum polybrominated diphenyl ethers (PBDEs) (plasma), 12-100-fold greater than those of noncoastal condors. The mean plasma DDE concentration for coastal condors was 500 ± 670 (standard deviation) (n = 22) versus 24 ± 24 (standard deviation) (n = 8) ng/g of wet weight for noncoastal condors, and simulations predicted ∼40% of breeding-age coastal condors have DDE levels associated with eggshell thinning in other avian species. Our analyses demonstrate potentially harmful levels of marine contaminant transfer to California condors, which could hinder the recovery of this terrestrial species.


Assuntos
Aves , Ecossistema , Animais , California , Diclorodifenil Dicloroetileno , Hidrocarbonetos Clorados , Bifenilos Policlorados
11.
J Wildl Dis ; 51(4): 901-6, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26251991

RESUMO

Lead poisoning from ingestion of spent lead ammunition is one of the greatest threats to the recovery of California Condors (Gymnogyps californianus) in the wild. Trash ingestion by condors is well documented, yet the extent that trash presents a lead exposure risk is unknown. We evaluated 1,413 trash items collected from condor nest areas and nestlings in the Transverse Range of Ventura County, California, US, from 2002 to 2008, for their potential as a lead exposure risk to condors. We visually identified 71 items suspected to contain sufficient lead to be of toxicologic concern. These items were leached with weak acid and analyzed for lead. Twenty-seven of the 71 leached items (~2% of the 1,413 items) were "lead containing" based on criteria of a leachate lead concentration >1 µg/mL, with the majority of these items (22; 81% of the 27 lead items) being ammunition related (e.g., spent bullet casings and jacketed bullets). Only three of the 1,413 items collected were lead containing but were clearly not ammunition related; the other two lead-containing items were unidentified. Our results suggest that trash ingestion of nonammunition items does not pose a significant lead exposure risk to the California Condor population in California.


Assuntos
Espécies em Perigo de Extinção , Poluentes Ambientais/toxicidade , Falconiformes , Chumbo/toxicidade , Resíduos Sólidos/análise , Animais , Poluentes Ambientais/química , Chumbo/química , Metais/química , Fatores de Risco
12.
Environ Res ; 134: 270-9, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25173094

RESUMO

Lead poisoning is preventing the recovery of the critically endangered California condor (Gymnogyps californianus) and lead isotope analyses have demonstrated that ingestion of spent lead ammunition is the principal source of lead poisoning in condors. Over an 8 month period in 2009, three lead-poisoned condors were independently presented with birdshot embedded in their tissues, evidencing they had been shot. No information connecting these illegal shooting events existed and the timing of the shooting(s) was unknown. Using lead concentration and stable lead isotope analyses of feathers, blood, and recovered birdshot, we observed that: i) lead isotope ratios of embedded shot from all three birds were measurably indistinguishable from each other, suggesting a common source; ii) lead exposure histories re-constructed from feather analysis suggested that the shooting(s) occurred within the same timeframe; and iii) two of the three condors were lead poisoned from a lead source isotopically indistinguishable from the embedded birdshot, implicating ingestion of this type of birdshot as the source of poisoning. One of the condors was subsequently lead poisoned the following year from ingestion of a lead buckshot (blood lead 556 µg/dL), illustrating that ingested shot possess a substantially greater lead poisoning risk compared to embedded shot retained in tissue (blood lead ~20 µg/dL). To our knowledge, this is the first study to use lead isotopes as a tool to retrospectively link wildlife shooting events.


Assuntos
Espécies em Perigo de Extinção , Isótopos/análise , Chumbo/análise , Aves Predatórias , Animais , California , Plumas/química
13.
Arch Environ Contam Toxicol ; 64(3): 484-93, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23203584

RESUMO

We evaluated mercury (Hg) exposure and two biomarkers, metallothionein (MT) gene expression and histopathological alterations in a wild fish species, largemouth bass (Micropterus salmoides), collected from the Sacramento-San Joaquin Delta, CA, a region polluted with Hg from historic mining activities. Hg is highly toxic and can disrupt multiple physiological systems in vertebrate species, including the immune system. Total mercury (THg) concentration in muscle tissue ranged from 0.12 to 0.98 ppm (wet weight) and was not related to body condition (r (2) = 0.005, p = 0.555). Using linear regression analysis, we found a positive relationship between MT gene expression (as determined using quantitative polymerase chain reaction) and copper, zinc, manganese, aluminum, and nickel (decreased to one variable by way of principal component analysis) (r (2) = 0.379, p = 0.044), a negative relationship with selenium (r (2) = 0.487, p = 0.017), and a weak, negative relationship with THg concentrations (r (2) = 0.337, p = 0.061). Juvenile largemouth bass collected from Hg-contaminated areas displayed histopathological features of immunosuppression compared with those collected from less contaminated areas as evidenced by significantly lower macrophage density in kidney and liver tissue (p = 0.018 and 0.020, respectively), greater trematode density in liver tissue (p = 0.014), and a greater number of adult trematodes. Our results suggest that largemouth bass may be experiencing sublethal effects from chronic Hg exposure. Furthermore, our findings illustrate the utility of examining multiple sublethal markers of effect to assess the impacts of contaminant exposure on physiological function in wild species.


Assuntos
Bass , Exposição Ambiental/análise , Monitoramento Ambiental/métodos , Mercúrio/análise , Rios/química , Poluentes Químicos da Água/análise , Envelhecimento/imunologia , Envelhecimento/metabolismo , Animais , Bass/imunologia , Bass/metabolismo , Biomarcadores/análise , Biomarcadores/metabolismo , California , Expressão Gênica/efeitos dos fármacos , Rim/efeitos dos fármacos , Rim/imunologia , Rim/patologia , Modelos Lineares , Fígado/efeitos dos fármacos , Fígado/imunologia , Fígado/patologia , Mercúrio/farmacocinética , Mercúrio/toxicidade , Metalotioneína/genética , Baço/efeitos dos fármacos , Baço/imunologia , Baço/patologia , Oligoelementos/análise , Oligoelementos/metabolismo , Poluentes Químicos da Água/farmacocinética , Poluentes Químicos da Água/toxicidade
14.
Proc Natl Acad Sci U S A ; 109(28): 11449-54, 2012 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-22733770

RESUMO

Endangered species recovery programs seek to restore populations to self-sustaining levels. Nonetheless, many recovering species require continuing management to compensate for persistent threats in their environment. Judging true recovery in the face of this management is often difficult, impeding thorough analysis of the success of conservation programs. We illustrate these challenges with a multidisciplinary study of one of the world's rarest birds-the California condor (Gymnogyps californianus). California condors were brought to the brink of extinction, in part, because of lead poisoning, and lead poisoning remains a significant threat today. We evaluated individual lead-related health effects, the efficacy of current efforts to prevent lead-caused deaths, and the consequences of any reduction in currently intensive management actions. Our results show that condors in California remain chronically exposed to harmful levels of lead; 30% of the annual blood samples collected from condors indicate lead exposure (blood lead ≥ 200 ng/mL) that causes significant subclinical health effects, measured as >60% inhibition of the heme biosynthetic enzyme δ-aminolevulinic acid dehydratase. Furthermore, each year, ∼20% of free-flying birds have blood lead levels (≥450 ng/mL) that indicate the need for clinical intervention to avert morbidity and mortality. Lead isotopic analysis shows that lead-based ammunition is the principle source of lead poisoning in condors. Finally, population models based on condor demographic data show that the condor's apparent recovery is solely because of intensive ongoing management, with the only hope of achieving true recovery dependent on the elimination or substantial reduction of lead poisoning rates.


Assuntos
Intoxicação por Chumbo/etiologia , Intoxicação por Chumbo/veterinária , Animais , Animais Selvagens , Doenças das Aves/induzido quimicamente , Doenças das Aves/prevenção & controle , California , Conservação dos Recursos Naturais/métodos , Ecologia , Espécies em Perigo de Extinção , Exposição Ambiental/análise , Exposição Ambiental/prevenção & controle , Monitoramento Ambiental , Poluentes Ambientais , Intoxicação por Chumbo/sangue
15.
J Wildl Dis ; 48(1): 95-112, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22247378

RESUMO

We document causes of death in free-ranging California Condors (Gymnogyps californianus) from the inception of the reintroduction program in 1992 through December 2009 to identify current and historic mortality factors that might interfere with establishment of self-sustaining populations in the wild. A total of 135 deaths occurred from October 1992 (the first post-release death) through December 2009, from a maximum population-at-risk of 352 birds, for a cumulative crude mortality rate of 38%. A definitive cause of death was determined for 76 of the 98 submitted cases, 70% (53/76) of which were attributed to anthropogenic causes. Trash ingestion was the most important mortality factor in nestlings (proportional mortality rate [PMR] 73%; 8/11), while lead toxicosis was the most important factor in juveniles (PMR 26%; 13/50) and adults (PMR 67%; 10/15). These results demonstrate that the leading causes of death at all California Condor release sites are anthropogenic. The mortality factors thought to be important in the decline of the historic California Condor population, particularly lead poisoning, remain the most important documented mortality factors today. Without effective mitigation, these factors can be expected to have the same effects on the sustainability of the wild populations as they have in the past.


Assuntos
Doenças das Aves/mortalidade , Conservação dos Recursos Naturais/métodos , Poluentes Ambientais/efeitos adversos , Falconiformes , Intoxicação por Chumbo/veterinária , Animais , Animais Selvagens , Doenças das Aves/sangue , Doenças das Aves/epidemiologia , California , Causas de Morte , Exposição Ambiental , Monitoramento Ambiental , Monitoramento Epidemiológico , Feminino , Chumbo/sangue , Intoxicação por Chumbo/epidemiologia , Intoxicação por Chumbo/mortalidade , Masculino
16.
Conserv Biol ; 23(4): 879-86, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19183215

RESUMO

Leadership is a critical tool for expanding the influence of conservation science, but recent advances in leadership concepts and practice remain underutilized by conservation scientists. Furthermore, an explicit conceptual foundation and definition of leadership in conservation science are not available in the literature. Here we drew on our diverse leadership experiences, our reading of leadership literature, and discussions with selected conservation science leaders to define conservation-science leadership, summarize an exploratory set of leadership principles that are applicable to conservation science, and recommend actions to expand leadership capacity among conservation scientists and practitioners. We define 2 types of conservation-science leadership: shaping conservation science through path-breaking research, and advancing the integration of conservation science into policy, management, and society at large. We focused on the second, integrative type of leadership because we believe it presents the greatest opportunity for improving conservation effectiveness. We identified 8 leadership principles derived mainly from the "adaptive leadership" literature: recognize the social dimension of the problem; cycle frequently through action and reflection; get and maintain attention; combine strengths of multiple leaders; extend your reach through networks of relationships; strategically time your effort; nurture productive conflict; and cultivate diversity. Conservation scientists and practitioners should strive to develop themselves as leaders, and the Society for Conservation Biology, conservation organizations, and academia should support this effort through professional development, mentoring, teaching, and research.


Assuntos
Conservação dos Recursos Naturais , Liderança
17.
Conserv Biol ; 22(1): 16-26, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18254849

RESUMO

Invasive rats are some of the largest contributors to seabird extinction and endangerment worldwide. We conducted a meta-analysis of studies on seabird-rat interactions to examine which seabird phylogenetic, morphological, behavioral, and life history characteristics affect their susceptibility to invasive rats and to identify which rat species have had the largest impact on seabird mortality. We examined 94 manuscripts that demonstrated rat effects on seabirds. All studies combined resulted in 115 independent rat-seabird interactions on 61 islands or island chains with 75 species of seabirds in 10 families affected. Seabirds in the family Hydrobatidae and other small, burrow-nesting seabirds were most affected by invasive rats. Laridae and other large, ground-nesting seabirds were the least vulnerable to rats. Of the 3 species of invasive rats, Rattus rattus had the largest mean impact on seabirds followed by R. norvegicus and R. exulans; nevertheless, these differences were not statistically significant. Our findings should help managers and conservation practitioners prioritize selection of islands for rat eradication based on seabird life history traits, develop testable hypotheses for seabird response to rat eradication, provide justification for rat eradication campaigns, and identify suitable levels of response and prevention measures to rat invasion. Assessment of the effects of rats on seabirds can be improved by data derived from additional experimental studies, with emphasis on understudied seabird families such as Sulidae, Phalacrocoracidae, Spheniscidae, Fregatidae, Pelecanoididae, Phaethontidae, and Diomedeidae and evaluation of rat impacts in tropical regions.


Assuntos
Charadriiformes/fisiologia , Conservação dos Recursos Naturais/métodos , Ecossistema , Animais , Ratos
18.
Environ Toxicol Chem ; 26(9): 1896-903, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17702543

RESUMO

Environmental pollution is ubiquitous and can pose a significant threat to wild populations through declines in fitness and population numbers. To elucidate the impact of marine pollution on a pelagic species, we assessed whether toxic contaminants accumulated in black-footed albatross (Phoebastria nigripes), a wide-ranging North Pacific predator, are correlated with altered physiological function. Blood samples from adult black-footed albatrosses on Midway Atoll, part of the Hawaiian (USA) archipelago, were analyzed for organochlorines (e.g., polychlorinated biphenyls [PCBs] and chlorinated pesticides), trace metals (silver, cadmium, tin, lead, chromium, nickel, copper, zinc, arsenic, selenium, and total mercury), and a sensitive physiological marker, peripheral white blood cell immune function (mitogen-induced lymphocyte proliferation and macrophage phagocytosis). We found a positive significant relationship between organochlorines, which were highly correlated within individual birds (p < 0.001, r > 0.80, Spearman correlation for all comparisons; PCBs, 160 +/- 60 ng/ml plasma [mean +/- standard deviation]; DDTs, 140 +/- 180 ng/ml plasma; chlordanes, 7.0 +/- 3.6 ng/ml plasma; hexachlorobenzene, 2.4 +/- 1.5 ng/ml plasma; n = 15) and increased lymphocyte proliferation (p = 0.020) as well as percentage lymphocytes (p = 0.033). Mercury was elevated in black-footed albatrosses (4,500 +/- 870 ng/ml whole blood, n = 15), and high mercury levels appeared to be associated (p = 0.017) with impaired macrophage phagocytosis. The associations we documented between multiple contaminant concentrations and immune function in endangered black-footed albatrosses provide some of the first evidence that albatrosses in the North Pacific may be affected by environmental contamination. Our results raise concern regarding detrimental health effects in pelagic predators exposed to persistent marine pollutants.


Assuntos
Aves/imunologia , Poluentes Químicos da Água/toxicidade , Envelhecimento/fisiologia , Animais , Aves/sangue , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Cor , Feminino , Saúde , Linfócitos/efeitos dos fármacos , Masculino , Fagócitos/efeitos dos fármacos
19.
Environ Sci Technol ; 37(15): 3256-60, 2003 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-12966967

RESUMO

The sources and risk factors for lead exposure to humans are relatively well recognized, yet much less is known about lead exposure risks and effects to wildlife. Here we utilized lead isotopic fingerprinting to investigate sources of elevated lead exposure to Laysan albatross (Phoebastria immutabilis) chicks in the Midway Island National Wildlife Refuge, which was established on the site of a decommissioned military base that previously had undergone lead remediation. Whole blood from chicks as well as soil and paint chips from the chicks' nests were collected from birds nesting close to (<5 m, building site) and distant from (>100 m, reference site) buildings and analyzed for lead levels and isotopic compositions using magnetic sector ICP-MS. Blood lead levels of chicks from the building site had a geometric mean of 190 microg/dL (average = 320 +/- 310 SD, range = 6.8-1400, n = 21) as compared to 4.5 microg/dL (average = 6.0 +/- 4.2 SD, range = 1.2-13, n = 15) in chicks from the reference site. Nest soil lead levels from both sites were similar and relatively low (0.05-11 microg/g) unless visibly contaminated with paint chips (building site). Isotopic analyses confirmed that leaded paint was the source of lead poisoning in these chicks and showed that the pathway of exposure was via direct ingestion of paint chips and not through contaminated soil. This study found continued risk to wildlife and possibly humans from lead hazards in a wildlife refuge established on a decommissioned military base. In addition, this study demonstrates the utility of lead isotopes to identify environmental lead hazards and exposure pathways to wildlife.


Assuntos
Animais Selvagens , Exposição Ambiental , Intoxicação por Chumbo/veterinária , Pintura , Poluentes do Solo/análise , Animais , Animais Recém-Nascidos , Conservação dos Recursos Naturais , Arquitetura de Instituições de Saúde , Humanos , Militares , Medição de Risco
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