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1.
Conserv Physiol ; 12(1): coae029, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38779433

RESUMO

Accretion of body fat by animals is an important physiological adaptation that may underpin seasonal behaviours, especially where it modulates risk associated with a particular behaviour. Using movement data from male Sierra Nevada bighorn sheep (Ovis canadensis sierrae), we tested the hypothesis that migratory behaviours were risk-sensitive to physiological state (indexed by body fat). Sierra bighorn face severe winter conditions at high elevations and higher predation risk at lower elevations. Given that large body fat stores ameliorate starvation risk, we predicted that having small body fat stores would force animals to migrate to lower elevations with more abundant food supplies. We also predicted that body fat stores would influence how far animals migrate, with the skinniest animals migrating the furthest down in elevation (to access the most abundant food supplies at that time of year). Lastly, we predicted that population-level rates of switching between migratory tactics would be inversely related to body fat levels because as body fat levels decrease, animals exhibiting migratory plasticity should modulate their risk of starvation by switching migratory tactics. Consistent with our predictions, probability of migration and elevational distance migrated increased with decreasing body fat, but effects differed amongst metapopulations. Population-level switching rates also were inversely related to population-level measures of body fat prior to migration. Collectively, our findings suggest migration was risk-sensitive to physiological state, and failure to accrete adequate fat may force animals to make trade-offs between starvation and predation risk. In complex seasonal environments, risk-sensitive migration yields a layer of flexibility that should aid long-term persistence of animals that can best modulate their risk by attuning behaviour to physiological state.

2.
J Mammal ; 104(4): 820-832, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37545667

RESUMO

Carnivores play critical roles in ecosystems, yet many species are declining worldwide. The Sierra Nevada Red Fox (Vulpes vulpes necator; SNRF) is a rare and endangered subspecies of red fox limited to upper montane forests, subalpine, and alpine environments of California and Oregon, United States. Having experienced significant distribution contractions and population declines in the last century, the subspecies is listed as at-risk by relevant federal and state agencies. Updated information on its contemporary distribution and density is needed to guide and evaluate conservation and management actions. We combined 12 years (2009-2020) of detection and nondetection data collected throughout California and Oregon to model the potential distribution and density of SNRFs throughout their historical and contemporary ranges. We used an integrated species distribution and density modeling approach, which predicted SNRF density in sampled locations based on observed relationships between environmental covariates and detection frequencies, and then projected those predictions to unsampled locations based on the estimated correlations with environmental covariates. This approach provided predictions that serve as density estimates in sampled regions and projections in unsampled areas. Our model predicted a density of 1.06 (95% credible interval = 0.8-1.36) foxes per 100 km2 distributed throughout 22,926 km2 in three distinct regions of California and Oregon-Sierra Nevada, Lassen Peak, and Oregon Cascades. SNRFs were most likely to be found in areas with low minimum temperatures and high snow water equivalent. Our results provide a contemporary baseline to inform the development and evaluation of conservation and management actions, and guide future survey efforts.

3.
J Phys Chem A ; 127(20): 4492-4502, 2023 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-37163697

RESUMO

Master equation simulations of the unimolecular reaction dynamics of the Criegee intermediate methacrolein oxide (MACR oxide) have been performed under a variety of temperature and pressure conditions. These simulations provide insight into how the unimolecular kinetics vary across temperatures spanning the range 288-320 K. This work has incorporated a new potential energy surface and includes the anti-to-syn and cis-to-trans conformational dynamics of MACR oxide, as well as the unimolecular reactions to form dioxirane and dioxole species. The competition between the unimolecular reactivity of MACR oxide and previously documented bimolecular reactivity of MACR oxide with water vapor is explored, focusing on how this competition is affected by changes in atmospheric conditions. The impact on the role of MACR oxide as an atmospheric oxidant of SO2 is noted.

4.
Proc Natl Acad Sci U S A ; 120(13): e2220030120, 2023 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-36940341

RESUMO

Mitigating human-caused mortality for large carnivores is a pressing global challenge for wildlife conservation. However, mortality is almost exclusively studied at local (within-population) scales creating a mismatch between our understanding of risk and the spatial extent most relevant to conservation and management of wide-ranging species. Here, we quantified mortality for 590 radio-collared mountain lions statewide across their distribution in California to identify drivers of human-caused mortality and investigate whether human-caused mortality is additive or compensatory. Human-caused mortality, primarily from conflict management and vehicles, exceeded natural mortality despite mountain lions being protected from hunting. Our data indicate that human-caused mortality is additive to natural mortality as population-level survival decreased as a function of increasing human-caused mortality and natural mortality did not decrease with increased human-caused mortality. Mortality risk increased for mountain lions closer to rural development and decreased in areas with higher proportions of citizens voting to support environmental initiatives. Thus, the presence of human infrastructure and variation in the mindset of humans sharing landscapes with mountain lions appear to be primary drivers of risk. We show that human-caused mortality can reduce population-level survival of large carnivores across large spatial scales, even when they are protected from hunting.


Assuntos
Carnívoros , Puma , Animais , Humanos , Ecossistema , Ecologia , Conservação dos Recursos Naturais
7.
Int J Prison Health ; 17(1): 54-68, 2021 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-33634654

RESUMO

PURPOSE: The purpose of this study is to synthesise the available peer-reviewed literature on the impact of time out of cell (TOOC) and time in purposeful activity (TIPA) on adverse mental outcomes amongst people in prison. DESIGN/METHODOLOGY/APPROACH: The outcomes of interest of this literature review were mental health, suicide, deliberate self-harm (DSH) and violence. Exposures of interest were TOOC, TIPA or a partial or indirect measure of either. In total, 14 studies were included. An abbreviated review methodology was used because of time constraints. FINDINGS: There was consistent evidence of an association between lower TOOC and TIPA and worse mental health and higher suicide risk. Limited evidence suggests a link between TOOC and DSH. No evidence was identified regarding the relationship between TOOC/TIPA and violence. RESEARCH LIMITATIONS/IMPLICATIONS: A lack of longitudinal studies prevents conclusions regarding causality. Significant heterogeneity of mental health outcomes limits the comparability of studies. PRACTICAL IMPLICATIONS: These findings highlight the importance of considering the impact of TOOC and TIPA on adverse mental outcomes for prisoners when designing prison regimes, including during urgent adaptation of such regimes in response to Covid-19. They are likely to be of interest to practitioners and policymakers concerned with prison regime design. ORIGINALITY/VALUE: This paper is the first to synthesise the existing literature on the impact of TOOC and TIPA on mental health outcomes.


Assuntos
Espaços Confinados , Estabelecimentos Correcionais , Saúde Mental , Prisioneiros/psicologia , Isolamento Social/psicologia , COVID-19 , Feminino , Humanos , Masculino , SARS-CoV-2 , Estresse Psicológico
8.
BMC Med Educ ; 21(1): 58, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33451314

RESUMO

BACKGROUND: Reflective practice is a key skill for healthcare professionals. E-learning programmes have the potential to develop reflective practice in remote settings and low- and middle-income countries (LMICs), where access to in-person reflective groups may be reduced. 'Aqoon' is a global mental health peer-to-peer e-learning programme between Somaliland and UK medical students. We aimed to explore participants' experiences of participating in the Aqoon programme, including their experiences of reflective practice. METHODS: Thirty-three medical students (22 Somaliland, 11 UK) enrolled in Aqoon. We matched volunteer learners in trios, to meet online to discuss anonymised clinical cases relevant to chapters of the World Health Organization's mental health gap action programme (mhGAP) intervention guide. We conducted thematic analysis of learners' reflective writing and post-programme focus group transcripts. RESULTS: Twenty-four students (73%) attended at least three online discussions (14 Somaliland, 10 UK). Somaliland and UK students described improved reflective skills and greater recognition of stigma towards mental ill-health. Themes included gaining memorable insights from peer discussions which would impact their medical education. UK students emphasised improved cultural understanding of common psychiatric presentations whilst Somaliland students reflected on increased clinical confidence. DISCUSSION: Integrating reflective practice into Aqoon showed the potential for low-cost e-learning interventions to develop cross-cultural reflective practice among medical students in diverse settings.


Assuntos
Instrução por Computador , Educação Médica , Estudantes de Medicina , Etnopsicologia , Humanos , Reino Unido
9.
J Mammal ; 101(5): 1244-1256, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-33335453

RESUMO

Bighorn sheep (Ovis canadensis) can live in extremely harsh environments and subsist on submaintenance diets for much of the year. Under these conditions, energy stored as body fat serves as an essential reserve for supplementing dietary intake to meet metabolic demands of survival and reproduction. We developed equations to predict ingesta-free body fat in bighorn sheep using ultrasonography and condition scores in vivo and carcass measurements postmortem. We then used in vivo equations to investigate the relationships between body fat, pregnancy, overwinter survival, and population growth in free-ranging bighorn sheep in California and Nevada. Among 11 subpopulations that included alpine winter residents and migrants, mean ingesta-free body fat of lactating adult females during autumn ranged between 8.8% and 15.0%; mean body fat for nonlactating females ranged from 16.4% to 20.9%. In adult females, ingesta-free body fat > 7.7% during January (early in the second trimester) corresponded with a > 90% probability of pregnancy and ingesta-free body fat > 13.5% during autumn yielded a probability of overwinter survival > 90%. Mean ingesta-free body fat of lactating females in autumn was positively associated with finite rate of population increase (λ) over the subsequent year in bighorn sheep subpopulations that wintered in alpine landscapes. Bighorn sheep with ingesta-free body fat of 26% in autumn and living in alpine environments possess energy reserves sufficient to meet resting metabolism for 83 days on fat reserves alone. We demonstrated that nutritional condition can be a pervasive mechanism underlying demography in bighorn sheep and characterizes the nutritional value of their occupied ranges. Mountain sheep are capital survivors in addition to being capital breeders, and because they inhabit landscapes with extreme seasonal forage scarcity, they also can be fat reserve obligates. Quantifying nutritional condition is essential for understanding the quality of habitats, how it underpins demography, and the proximity of a population to a nutritional threshold.

10.
Br J Psychiatry ; 217(4): 535-536, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32241320

RESUMO

The General Medical Council has introduced a generic professional capabilities framework. It includes the need to develop the professional values, actions and aspirations fundamental to becoming a 'dedicated doctor'. The history of psychiatry has potential to facilitate this learning, both by an understanding of content and the ability to think historically.


Assuntos
Currículo , Psiquiatria/educação , Psiquiatria/história , História do Século XIX , História do Século XX , Humanos
11.
Ecol Evol ; 10(24): 13687-13704, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33391673

RESUMO

Wildlife restoration often involves translocation efforts to reintroduce species and supplement small, fragmented populations. We examined the genomic consequences of bighorn sheep (Ovis canadensis) translocations and population isolation to enhance understanding of evolutionary processes that affect population genetics and inform future restoration strategies. We conducted a population genomic analysis of 511 bighorn sheep from 17 areas, including native and reintroduced populations that received 0-10 translocations. Using the Illumina High Density Ovine array, we generated datasets of 6,155 to 33,289 single nucleotide polymorphisms and completed clustering, population tree, and kinship analyses. Our analyses determined that natural gene flow did not occur between most populations, including two pairs of native herds that had past connectivity. We synthesized genomic evidence across analyses to evaluate 24 different translocation events and detected eight successful reintroductions (i.e., lack of signal for recolonization from nearby populations) and five successful augmentations (i.e., reproductive success of translocated individuals) based on genetic similarity with the source populations. A single native population founded six of the reintroduced herds, suggesting that environmental conditions did not need to match for populations to persist following reintroduction. Augmentations consisting of 18-57 animals including males and females succeeded, whereas augmentations of two males did not result in a detectable genetic signature. Our results provide insight on genomic distinctiveness of native and reintroduced herds, information on the relative success of reintroduction and augmentation efforts and their associated attributes, and guidance to enhance genetic contribution of augmentations and reintroductions to aid in bighorn sheep restoration.

12.
J Anim Ecol ; 89(4): 1032-1044, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31854458

RESUMO

The resource hierarchy hypothesis predicts that the most important factors limiting a species' distribution act at the coarsest spatial scales. However, resource selection behaviour affords mobile organisms the opportunity to adopt a range of tactics for navigating spatial trade-offs between competing biotic and abiotic constraints. Throughout the animal kingdom, partial migration (where some individuals migrate, and others remain resident year round) offers a pervasive example of such behavioural polymorphism. Identifying the differences between these behaviours is therefore central to understanding the conditions (habitat) needed to sustain migrant and resident populations. Here we test an extension of the resource hierarchy hypothesis. We hypothesized that rather than responding to a single limiting factor, migration and residency represent contrasting scale-specific approaches to managing trade-offs between forage, predation risk and severe winter conditions. Furthermore, we predicted that the distribution of habitat selected by migrants and residents is predictive of the local prevalence of migratory behaviour. To test these hypotheses, we quantified migratory status- (resident/migrant) and season-specific (winter/summer) differences in resource selection by eight populations of federally endangered Sierra Nevada bighorn sheep Ovis canadensis sierrae across three spatial scales: population range, individual range and within individual range. We then integrated these spatial predictions to produce separate spatial predictions of migrant and resident winter habitat. As predicted, model selection provided strong evidence for the importance of status-specific differences in resource selection. Residents showed stronger coarse-scale selection for terrain associated with predator avoidance and stronger fine-scale selection for greenness, while in migrants this pattern was reversed. Availability of migrant habitat predicted the local prevalence of migration (top model pseudo R2 of .87). Our ability to respond to global declines of migratory species depends on improving our understanding of the conditions required to maintain migratory behaviour. Through explicitly contrasting migrant and resident behaviour, our results illustrate seasonal differences in migrant and resident habitat and how these two behaviours represent responses to different limiting conditions. Our analyses provides a novel empirical basis for assessing the local prevalence of migratory behaviour across large landscapes.


Assuntos
Migração Animal , Cervos , Animais , Ecossistema , Comportamento Predatório , Prevalência , Estações do Ano
13.
BJPsych Open ; 5(3): e43, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31530315

RESUMO

SUMMARY: 'Rebound' or 'withdrawal' symptoms are frequently observed after a sudden discontinuation of clozapine. We describe a patient with treatment-resistant schizoaffective disorder who developed agranulocytosis on clozapine but was successfully switched to treatment with olanzapine with no deterioration in her condition. We put forward three possible theories which may have accounted for the lack of rebound symptoms in this patient: the pharmacological profile of olanzapine, the anticholinergic effects of hyoscine hydrobromide, and the possibility that this patient may not be treatment-resistant and so have a reduced risk of rebound psychosis due to displaying a different pathophysiology. DECLARATION OF INTEREST: None.

14.
Stud Health Technol Inform ; 264: 413-417, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31437956

RESUMO

Suicidal ideation is a risk factor for self-harm, completed suicide and can be indicative of mental health issues. Adolescents are a particularly vulnerable group, but few studies have examined suicidal behaviour prevalence in large cohorts. Electronic Health Records (EHRs) are a rich source of secondary health care data that could be used to estimate prevalence. Most EHR documentation related to suicide risk is written in free text, thus requiring Natural Language Processing (NLP) approaches. We adapted and evaluated a simple lexicon- and rule-based NLP approach to identify suicidal adolescents from a large EHR database. We developed a comprehensive manually annotated EHR reference standard and assessed NLP performance at both document and patient level on data from 200 patients ( 5000 documents). We achieved promising results (>80% f1 score at both document and patient level). Simple NLP approaches can be successfully used to identify patients who exhibit suicidal risk behaviour, and our proposed approach could be useful for other populations and settings.


Assuntos
Processamento de Linguagem Natural , Suicídio , Adolescente , Registros Eletrônicos de Saúde , Humanos , Saúde Mental , Ideação Suicida
16.
Nat Commun ; 9(1): 2007, 2018 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-29789526

RESUMO

Hox gene transcription factors are important regulators of positional identity along the anterior-posterior axis in bilaterian animals. Cnidarians (e.g., sea anemones, corals, and hydroids) are the sister group to the Bilateria and possess genes related to both anterior and central/posterior class Hox genes. Here we report a previously unrecognized domain of Hox expression in the starlet sea anemone, Nematostella vectensis, beginning at early blastula stages. We explore the relationship of two opposing Hox genes (NvAx6/NvAx1) expressed on each side of the blastula during early development. Functional perturbation reveals that NvAx6 and NvAx1 not only regulate their respective expression domains, but also interact with Wnt genes to pattern the entire oral-aboral axis. These findings suggest an ancient link between Hox/Wnt patterning during axis formation and indicate that oral-aboral domains are likely established during blastula formation in anthozoan cnidarians.


Assuntos
Padronização Corporal/genética , Regulação da Expressão Gênica no Desenvolvimento , Genes Homeobox , Anêmonas-do-Mar/genética , Proteínas Wnt/genética , Animais , Blástula/citologia , Blástula/crescimento & desenvolvimento , Blástula/metabolismo , Gastrulação/genética , Anêmonas-do-Mar/citologia , Anêmonas-do-Mar/crescimento & desenvolvimento , Transdução de Sinais , Proteínas Wnt/metabolismo
17.
Evodevo ; 6: 20, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26101582

RESUMO

BACKGROUND: The evolutionary origins of cell polarity in metazoan embryos are unclear. In most bilaterian animals, embryonic and cell polarity are set up during embryogenesis with the same molecules being utilized to regulate tissue polarity at different life stages. Atypical protein kinase C (aPKC), lethal giant larvae (Lgl), and Partitioning-defective (Par) proteins are conserved components of cellular polarization, and their role in establishing embryonic asymmetry and tissue polarity have been widely studied in model bilaterian groups. However, the deployment and role of these proteins in animals outside Bilateria has not been studied. We address this by characterizing the localization of different components of the Par system during early development of the sea anemone Nematostella vectensis, a member of the clade Cnidaria, the sister group to bilaterian animals. RESULTS: Immunostaining using specific N. vectensis antibodies and the overexpression of mRNA-reporter constructs show that components of the N. vectensis Par system (NvPar-1, NvPar-3, NvPar-6, NvaPKC, and NvLgl) distribute throughout the microtubule cytoskeleton of eggs and early embryos without clear polarization along any embryonic axis. However, they become asymmetrically distributed at later stages, when the embryo forms an ectodermal epithelial layer. NvLgl and NvPar-1 localize in the basolateral cortex, and NvaPKC, NvPar-6, and NvPar-3 at the apical zone of the cell in a manner seen in bilaterian animals. CONCLUSIONS: The cnidarian N. vectensis exhibits clear polarity at all stages of early embryonic development, which appears to be established independent of the Par system reported in many bilaterian embryos. However, in N. vectensis, using multiple immunohistochemical and fluorescently labeled markers in vivo, components of this system are deployed to organize epithelial cell polarity at later stages of development. This suggests that Par system proteins were co-opted to organize early embryonic cell polarity at the base of the Bilateria and that, therefore, different molecular mechanisms operate in early cnidarian embryogenesis.

18.
J Anim Ecol ; 82(2): 377-88, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23379674

RESUMO

Body reserves of numerous taxa follow seasonal rhythms that are a function of temporal patterns in food availability and life-history events; however, tests of the theory underlying the allocation of somatic reserves for long-lived organisms are rare, especially for free-ranging mammals. We evaluated the hypothesis that allocation of somatic reserves to survival (i.e., metabolic processes) and reproduction should be sensitive to current nutritional state relative to seasonal thresholds in those reserves. Our goal was to reveal the linkages between nutrition and life-history traits to understand how long-lived, iteroparous organisms balance the allocation of somatic reserves to reproduction, while retaining reserves as insurance for survival in unpredictable environments. Our evaluation was based on seasonal dynamics in fat (measured as ingesta-free body fat; IFBFat) and protein reserves (measured as ingesta-free, fat-free body mass; IFFFBMass) of 136 female mule deer (Odocoileus hemionus) over 8 years. Although mean changes in fat and protein reserves were positive over summer and negative over winter, accretion and catabolism of those reserves was not consistent among individuals. Over winter, both lipid and protein stores available in autumn were catabolized in proportion to their availability above a post-winter threshold (5·8% IFBFat, 33 kg IFFFBMass); however, lean body tissue was spared at the expense of lipid reserves. Female deer mostly synthesized lean body tissue over summer and committed post-winter fat reserves to reproduction relative to their availability above an autumn threshold (>8·6% IFBFat), which was lowered by 2·8 percentage points (pp) for each additional young recruited. Mothers reduced their autumn fat threshold to secure current reproductive investment and, thereby, endured a cost of reproduction at the expense of fat accumulation. Allocation of somatic reserves occurred in a risk-sensitive framework; females allocated reserves relative to their availability above seasonal thresholds. In contrast to current notions of summer accretion and winter catabolism of body reserves, some individuals deposited reserves over winter and catabolized reserves over summer, mainly because regulation of individual condition was state-dependent. Consequently, behaviour and life-history strategies may be as much a function of nutritional contributions of the previous season as of the current one.


Assuntos
Tecido Adiposo/fisiologia , Cervos/fisiologia , Longevidade , Proteínas/fisiologia , Estações do Ano , Animais , Composição Corporal , Feminino , Reprodução , Fatores de Risco
19.
Oecologia ; 171(1): 295-307, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22791131

RESUMO

Predation can disproportionately affect endangered prey populations when generalist predators are numerically linked to more abundant primary prey. Apparent competition, the term for this phenomenon, has been increasingly implicated in the declines of endangered prey populations. We examined the potential for apparent competition to limit the recovery of Sierra Nevada bighorn sheep (Ovis canadensis sierrae), an endangered subspecies under the US Endangered Species Act. Using a combination of location, demographic, and habitat data, we assessed whether cougar (Puma concolor) predation on endangered bighorn sheep was a consequence of their winter range overlap with abundant mule deer (Odocoileus hemionus). Consistent with the apparent competition hypothesis, bighorn sheep populations with higher spatial overlap with deer exhibited higher rates of cougar predation which had additive effects on adult survival. Bighorn sheep killed by cougars were primarily located within deer winter ranges, even though those areas constituted only a portion of the bighorn sheep winter ranges. We suspect that variation in sympatry between bighorn sheep and deer populations was largely driven by differences in habitat selection among bighorn sheep herds. Indeed, bighorn sheep herds that experienced the highest rates of predation and the greatest spatial overlap with deer also exhibited the strongest selection for low elevation habitat. Although predator-mediated apparent competition may limit some populations of bighorn sheep, it is not the primary factor limiting all populations, suggesting that the dynamics of different herds are highly idiosyncratic. Management plans for endangered species should consider the spatial distributions of key competitors and predators to reduce the potential for apparent competition to hijack conservation success.


Assuntos
Espécies em Perigo de Extinção , Cadeia Alimentar , Puma , Carneiro da Montanha , Animais , Conservação dos Recursos Naturais , Dinâmica Populacional , Territorialidade , Estados Unidos
20.
Conserv Biol ; 25(6): 1240-1249, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22070275

RESUMO

Evidence of inbreeding depression is commonly detected from the fitness traits of animals, yet its effects on population growth rates of endangered species are rarely assessed. We examined whether inbreeding depression was affecting Sierra Nevada bighorn sheep (Ovis canadensis sierrae), a subspecies listed as endangered under the U.S. Endangered Species Act. Our objectives were to characterize genetic variation in this subspecies; test whether inbreeding depression affects bighorn sheep vital rates (adult survival and female fecundity); evaluate whether inbreeding depression may limit subspecies recovery; and examine the potential for genetic management to increase population growth rates. Genetic variation in 4 populations of Sierra Nevada bighorn sheep was among the lowest reported for any wild bighorn sheep population, and our results suggest that inbreeding depression has reduced adult female fecundity. Despite this population sizes and growth rates predicted from matrix-based projection models demonstrated that inbreeding depression would not substantially inhibit the recovery of Sierra Nevada bighorn sheep populations in the next approximately 8 bighorn sheep generations (48 years). Furthermore, simulations of genetic rescue within the subspecies did not suggest that such activities would appreciably increase population sizes or growth rates during the period we modeled (10 bighorn sheep generations, 60 years). Only simulations that augmented the Mono Basin population with genetic variation from other subspecies, which is not currently a management option, predicted significant increases in population size. Although we recommend that recovery activities should minimize future losses of genetic variation, genetic effects within these endangered populations-either negative (inbreeding depression) or positive (within subspecies genetic rescue)-appear unlikely to dramatically compromise or stimulate short-term conservation efforts. The distinction between detecting the effects of inbreeding depression on a component vital rate (e.g., fecundity) and the effects of inbreeding depression on population growth underscores the importance of quantifying inbreeding costs relative to population dynamics to effectively manage endangered populations.


Resumen: La evidencia de la depresión por endogamia comúnmente es detectada a partir de atributos de la adaptabilidad de animales, sin embargo sus efectos sobre las tasas de crecimiento poblacional raramente son evaluados. Examinamos si la depresión por endogamia estaba afectando a Ovis canadensis sierrae, una subespecie enlistada como en peligro en el Acta de Especies en Peligro de E.U.A. Nuestros objetivos fueron caracterizar la variación genética de esta subespecie; probar si la depresión por endogamia afecta las tasas vitales (supervivencia de adultos y fecundidad de hembras); evaluar si la depresión por endogamia puede limitar la recuperación dela subespecie y examinar el potencial para el manejo genético para incrementar las tasas de crecimiento poblacional. La variación genética en 4 subpoblaciones O. c. sierrae fue la más baja entre las reportadas para cualquier otra población silvestre de O. c. sierrae y nuestros resultados sugieren que la depresión por endogamia ha reducido la fecundidad de hembras adultas. Sin embargo, los tamaños poblacionales y tasas de crecimiento predichos por modelos de proyección matriciales demostraron que la depresión por endogamia no inhibiría sustancialmente la recuperación de O. c. sierrae en las próximas 8 generaciones (48 años). Más aun, simulaciones del rescate genético no sugirieron que tales actividades incrementarían los tamaños poblacionales o tasas de crecimiento durante el período modelado (10 generaciones, 60 años). Solo las simulaciones que aumentaron la población de Mono Basin con variación genética de otras subespecies, lo cual no es una opción de manejo actual, predijeron incrementos significativos en el tamaño poblacional. Aunque recomendamos que las actividades de recuperación deberían minimizar pérdidas futuras en la variación genética, parece poco probable que los efectos genéticos en estas poblaciones en peligro-ya sea negativas (depresión por endogamia) o positivas (rescate genético de la subespecie)-comprometan o estimulen dramáticamente los esfuerzos de conservación a corto plazo. La distinción entre la detección de los efectos de la depresión por endogamia sobre una tasa vital componente (e.g., fecundidad) y los efectos de la depresión por endogamia sobre el crecimiento poblacional resalta la importancia de cuantificar, mediante datos recolectados en campo, los costos de la endogamia en relación con la dinámica poblacional para el manejo efectivo de poblaciones en peligro.


Assuntos
Espécies em Perigo de Extinção , Endogamia , Ovinos/fisiologia , Animais , Conservação dos Recursos Naturais , Feminino , Fertilidade , Variação Genética , Heterozigoto , Masculino , Repetições de Microssatélites , Modelos Genéticos , Nevada , Densidade Demográfica , Dinâmica Populacional , Comportamento Sexual Animal , Ovinos/genética
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