Human‐caused mortality of wildlife is a pervasive threat to biodiversity. Assessing the population‐level impact of fisheries bycatch and other human‐caused mortality of wildlife has typically relied ...upon deterministic methods. However, population declines are often accelerated by stochastic factors that are not accounted for in such conventional methods. Building on the widely applied potential biological removal (PBR) equation, we devised a new population modeling approach for estimating sustainable limits to human‐caused mortality and applied it in a case study of bottlenose dolphins affected by capture in an Australian demersal otter trawl fishery. Our approach, termed sustainable anthropogenic mortality in stochastic environments (SAMSE), incorporates environmental and demographic stochasticity, including the dependency of offspring on their mothers. The SAMSE limit is the maximum number of individuals that can be removed without causing negative stochastic population growth. We calculated a PBR of 16.2 dolphins per year based on the best abundance estimate available. In contrast, the SAMSE model indicated that only 2.3–8.0 dolphins could be removed annually without causing a population decline in a stochastic environment. These results suggest that reported bycatch rates are unsustainable in the long term, unless reproductive rates are consistently higher than average. The difference between the deterministic PBR calculation and the SAMSE limits showed that deterministic approaches may underestimate the true impact of human‐caused mortality of wildlife. This highlights the importance of integrating stochasticity when evaluating the impact of bycatch or other human‐caused mortality on wildlife, such as hunting, lethal control measures, and wind turbine collisions. Although population viability analysis (PVA) has been used to evaluate the impact of human‐caused mortality, SAMSE represents a novel PVA framework that incorporates stochasticity for estimating acceptable levels of human‐caused mortality. It offers a broadly applicable, stochastic addition to the demographic toolbox to evaluate the impact of human‐caused mortality on wildlife.
Resumen
La mortalidad de la fauna causada por humanos es una amenaza continua para la biodiversidad. El análisis del impacto a nivel poblacional de la captura pesquera incidental y otras causas humanas de la mortalidad de la fauna comúnmente ha dependido de métodos determinísticos. Sin embargo, las declinaciones poblacionales con frecuencia se aceleran por los factores estocásticos que no son considerados en dichos métodos convencionales. A partir de la ecuación de extirpación biológica potencial (EBP) de extensa aplicación diseñamos una nueva estrategia de modelación poblacional para estimar los límites sustentables de la mortalidad causada por humanos y la aplicamos en un estudio de caso de los delfines nariz de botella afectados por la captura en una pesquería australiana de arrastre demersal. Nuestra estrategia, denominada mortalidad antropogénica sustentable en ambientes estocásticos (MASAM) incorpora la estocasticidad ambiental y demográfica, incluyendo la dependencia que tienen las crías por sus madres. El límite MASAM es el número máximo de individuos que pueden extirparse sin causar un crecimiento poblacional estocástico negativo. Calculamos un EBP de 16.3 delfines por año con base en la mejor estimación de abundancia disponible. Como contraste, el modelo MASAM indicó que sólo podían extirparse entre 2.3 y 8.0 delfines anualmente sin ocasionar una declinación poblacional en un ambiente estocástico. Estos resultados sugieren que las tasas reportadas de captura incidental no son sustentables a largo plazo, a menos que las tasas reproductivas sean sistemáticamente más altas que el promedio. La diferencia entre el cálculo determinístico del EBP y los límites de MASAM mostró que los enfoques determinísticos pueden subestimar el verdadero impacto de la mortalidad de la fauna causada por humanos. Lo anterior resalta la importancia de integrar la estocasticidad al evaluar el impacto de la captura incidental y otras causas humanas de la mortalidad como la caza, las medidas letales de control y las colisiones con turbinas de viento. Aunque el análisis de viabilidad poblacional (AVP) se ha utilizado para evaluar el impacto de la mortalidad causada por humanos, MASAM representa un marco novedoso de AVP que incorpora la estocasticidad para estimar los niveles aceptables de mortalidad causada por humanos. Este enfoque ofrece una adición estocástica de aplicación generalizada para las herramientas demográficas usadas para evaluar el impacto de la mortalidad causada por humanos sobre la fauna.
【摘要】
在不断变化的情景下估计野生动物死亡率的持续性限度的随机模型
人类造成的野生动物死亡是对生物多样性的普遍威胁。目前, 通常依赖于确定性方法来评估渔业副渔获物和其它人为造成的野生动物死亡在种群水平上的影响。然而, 随机因素往往会加速种群数量的下降, 但这种常规方法没有将其纳入考虑。我们在已得到广泛应用的生物可移除潜在量(Potential Biological Removal, PBR)方程的基础上, 设计了一种新的种群建模方法来估计人为造成的死亡的可持续限度, 并将其应用于澳大利亚底层拖网渔业中受影响的瓶鼻海豚的案例研究。我们的方法可以称为“随机环境中的可持续人为影响死亡率(SAMSE)”, 包含了环境和种群的随机性, 还包括了后代对母亲的依赖性。SAMSE的极限是指在不引起负面的种群随机增长的情况下可以移除的最大个体数。我们根据现有最佳的丰度估计, 计算出海豚的生物可移除潜在量为每年16.2头。相比之下, SAMSE模型则显示, 在随机环境中, 为了不引起种群下降, 每年只能移除2.3至8.0头海豚。这些结果表明, 除非繁殖率持续高于平均水平, 否则长期来看报告的副渔获率是不可持续的。确定性的PBR计算和SAMSE限制之间的差异表明, 确定性方法可能低估了人为造成野生动物死亡的真实影响。这突出了整合随机性在评估副渔获或其它人为造成的死亡(如狩猎、灭杀控制措施和风力涡轮机碰撞)对野生动物的影响中的重要性。尽管种群生存力分析(PVA)已被用于评估人为造成死亡的影响, 但SAMSE代表了一个包含随机性的PVA新框架, 可以用于估计人为造成死亡的可接受水平。它为种群统计学工具补充了一种广泛适用的随机性方法, 以评估人类造成的死亡对野生动物的影响。【翻译:胡怡思;审校:聂永刚】
Article impact statement: The new SAMSE model incorporates stochasticity to provide better estimates of sustainable limits to wildlife mortality in a changing world.
Captive breeding programs aim to maintain populations that are demographically self-sustaining and genetically healthy. It has been well documented that the best way for managed breeding programs to ...retain gene diversity (GD) and limit inbreeding is to select breeding pairs that minimize a population's average kinship. We used a series of computer simulations to test 4 methods of minimizing average kinship across a variety of scenarios with varying generation lengths, mortality rates, reproductive rates, and rates of breeding pair success. "Static MK Selection" and "Dynamic MK Selection" are 2 methods for iteratively selecting genetically underrepresented individuals for breeding, whereas "Ranked MK Selection" and "Simultaneous MK Selection" are 2 methods for concurrently selecting the group of breeding individuals that produce offspring with the lowest average kinship. For populations with discrete generations (24 tested scenarios), we found that the Simultaneous and Ranked MK Selection methods were generally the best, nearly equivalent methods for selecting breeding pairs that retained GD and limited inbreeding. For populations with overlapping generations (198 tested scenarios), we found that Dynamic MK Selection was the most robust method for selecting breeding pairs. We used these results to provide guidelines for identifying which method of minimizing average kinship was most appropriate for various breeding program scenarios.
Ebola virus is highly lethal for great apes. Estimated mortality rates up to 98% have reduced the global gorilla population by approximately one-third. As mountain gorillas (Gorilla beringei ...beringei) are endangered, with just over 1000 individuals remaining in the world, an outbreak could decimate the population. Simulation modeling was used to evaluate the potential impact of an Ebola virus outbreak on the mountain gorilla population of the Virunga Massif. Findings indicate that estimated contact rates among gorilla groups are high enough to allow rapid spread of Ebola, with less than 20% of the population projected to survive at 100 days post-infection of just one gorilla. Despite increasing survival with vaccination, no modeled vaccination strategy prevented widespread infection. However, the model projected that survival rates greater than 50% could be achieved by vaccinating at least half the habituated gorillas within 3 weeks of the first infectious individual.
Summary
1. The concepts and algorithms for demographic and genetic analysis of pedigreed populations have been evolving rapidly in recent years.
2. The PMx software brings together into one ...integrated package a number of tools for pedigree analysis, including methods for dealing with missing, uncertain and probabilistic data not previously available in distributed software.
3. PMx provides tools for optimal demographic and genetic management of populations of wildlife species, rare domestic breeds, and other populations for which the primary goal is to conserve genetic diversity, and it is being implemented as the primary pedigree management tool for the breeding programmes of zoo associations around the world.
4. PMx can be used to characterize the demography and genetics of any captive or wild population for which pedigree and life‐history data are available.
Understanding cumulative effects of multiple threats is key to guiding effective management to conserve endangered species. The critically endangered, Southern Resident killer whale population of the ...northeastern Pacific Ocean provides a data-rich case to explore anthropogenic threats on population viability. Primary threats include: limitation of preferred prey, Chinook salmon; anthropogenic noise and disturbance, which reduce foraging efficiency; and high levels of stored contaminants, including PCBs. We constructed a population viability analysis to explore possible demographic trajectories and the relative importance of anthropogenic stressors. The population is fragile, with no growth projected under current conditions, and decline expected if new or increased threats are imposed. Improvements in fecundity and calf survival are needed to reach a conservation objective of 2.3% annual population growth. Prey limitation is the most important factor affecting population growth. However, to meet recovery targets through prey management alone, Chinook abundance would have to be sustained near the highest levels since the 1970s. The most optimistic mitigation of noise and contaminants would make the difference between a declining and increasing population, but would be insufficient to reach recovery targets. Reducing acoustic disturbance by 50% combined with increasing Chinook by 15% would allow the population to reach 2.3% growth.
► Different species concepts have a critical bearing on conservation of species. ► Many species contain small populations suffering from genetic deterioration. ► The phylogenetic species concept ...(PSC) often leads to excessive splitting. ► Excessive splitting may prevent genetic rescue and increase extinctions. ► For conservation purposes, species are best defined using reproductive isolation.
The ∼26 definitions of species often yield different numbers of species and disparate groupings, with financial, legal, biological and conservation implications. Using conservation genetic considerations, we demonstrate that different species concepts have a critical bearing on our ability to conserve species. Many species of animals and plants persist as small isolated populations suffering inbreeding depression, loss of genetic diversity, and elevated extinction risks. Such small populations usually can be rescued by restoring gene flow, but substantial genetic drift effects can lead them to be classified as distinct species under the diagnostic phylogenetic species concept. Minimum harm to fitness is done and maximum potential fitness and evolutionary potential benefits accrue when reproductive isolation (pre- and/or post-zygotic) is used as the criterion to define distinct species. For sympatric populations, distinct species are diagnosed by very limited gene flow. For allopatric populations, both minimal gene flow and evidence of reduced reproductive fitness in crosses (or effects predicted from adaptive differentiation among populations and/or fixed chromosomal differences) are required to satisfy conservation issues. Species delineations based upon the biological and differential fitness species concepts meet the above requirements. Conversely, if species are delineated using the diagnostic phylogenetic species concept, genetic rescue of small genetically isolated populations may require crosses between species, with consequent legal and regulatory ramifications that could preclude actions to prevent extinction. Consequently, we conclude that the diagnostic phylogenetic species concept is unsuitable for use in conservation contexts, especially for classifying allopatric populations.
Decades after a ban on hunting, and despite focused management interventions, the endangered St. Lawrence Estuary (SLE) beluga (Delphinapterus leucas) population has failed to recover. We applied a ...population viability analysis to simulate the responses of the SLE beluga population across a wide range of variability and uncertainty under current and projected changes in environmental and climate-mediated conditions. Three proximate threats to recovery were explored: ocean noise; contaminants; and prey limitation. Even the most optimistic scenarios failed to achieve the reliable positive population growth needed to meet current recovery targets. Here we show that predicted effects of climate change may be a more significant driver of SLE beluga population dynamics than the proximate threats we considered. Aggressive mitigation of all three proximate threats will be needed to build the population's resilience and allow the population to persist long enough for global actions to mitigate climate change to take effect.
•Decades after a hunting ban, the St. Lawrence Estuary beluga failed to recover.•Improved calf survival is vital to sustained population growth.•We explored threats to recovery: ocean noise; contaminants; and prey limitation.•Climate change is most significant driver of SLE beluga population dynamics.•Mitigation of all three proximate threats needed to build climate resilience.
Genetic rescue – ameliorating inbreeding depression and restoring genetic diversity of inbred populations through gene flow - is valuable in wildlife conservation. Empirically validated ...recommendations for genetic rescue supported by evolutionary genetics theory advise maximizing genetic diversity in target populations. Instead, recent papers based on genomic studies of island foxes, Isle Royal wolves, and simulation modeling claim it would be preferable to minimize introduction of harmful variation by avoiding genetic rescue altogether or by selecting partially-inbred sources presumed to have fewer harmful alleles. We examined the assertions and evidence underlying these new recommendations. The claim that long-term persistence of a few small inbred populations invalidates the small population paradigm commits the survivorship fallacy by ignoring population extinctions through inbreeding. The claim that island foxes show no inbreeding depression conflicts with elevated levels of putatively harmful alleles, low fecundity, and island-specific disease susceptibilities. The claim that the history of Isle Royale wolves represents likely outcomes of genetic rescues using immigrants from larger source populations is invalid: the unplanned addition of a single male to an inbred population capped at ~25 individuals does not represent sound genetic rescue. The simulations in Robinson et al. (2018, 2019) and Kyriazis et al. (2019 pre-print) apply several unrealistic assumptions and parameter distributions that disfavor large, outbred sources for genetic rescue. Accordingly, the simulations' conclusions conflict profoundly with those of >120 meta-analysed real datasets, and do not overturn current empirically validated recommendations to maximize genetic diversity in the target population.
•Inbreeding and loss of gene diversity are unavoidable in small isolated populations and increase extinction risks•Such populations can be often be rescued by gene flow from another population (genetic rescue)•Gene flow from genetically diverse populations is better at reversing genetic erosion than that from small populations•Proposals to minimize introduction of harmful variation are based on unrealistic simulations that contradict real-life outcomes•Maximizing genetic diversity in the target population is the best current strategy to improve fitness and ability to evolve
Wildlife population models have been criticized for their narrow disciplinary perspective when analyzing complexity in coupled biological - physical - human systems. We describe a "metamodel" ...approach to species risk assessment when diverse threats act at different spatiotemporal scales, interact in non-linear ways, and are addressed by distinct disciplines. A metamodel links discrete, individual models that depict components of a complex system, governing the flow of information among models and the sequence of simulated events. Each model simulates processes specific to its disciplinary realm while being informed of changes in other metamodel components by accessing common descriptors of the system, populations, and individuals. Interactions among models are revealed as emergent properties of the system. We introduce a new metamodel platform, both to further explain key elements of the metamodel approach and as an example that we hope will facilitate the development of other platforms for implementing metamodels in population biology, species risk assessments, and conservation planning. We present two examples - one exploring the interactions of dispersal in metapopulations and the spread of infectious disease, the other examining predator-prey dynamics - to illustrate how metamodels can reveal complex processes and unexpected patterns when population dynamics are linked to additional extrinsic factors. Metamodels provide a flexible, extensible method for expanding population viability analyses beyond models of isolated population demographics into more complete representations of the external and intrinsic threats that must be understood and managed for species conservation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Maintaining a living plant collection is the most common method of ex situ conservation for plant species that cannot be seed banked (i.e., exceptional species). Viability of living collections, and ...their value for future conservation efforts, can be limited without coordinated efforts to track and manage individuals across institutions. Using a pedigree‐focused approach, the zoological community has established an inter‐institutional infrastructure to support long‐term viability of captive animal populations. We assessed the ability of this coordinated metacollection infrastructure to support the conservation of 4 plant species curated in living collections at multiple botanic gardens around the world. Limitations in current practices include the inability to compile, share, and analyze plant collections data at the individual level, as well as difficulty in tracking original provenance of ex situ material. The coordinated metacollection framework used by zoos can be adopted by the botanical community to improve conservation outcomes by minimizing the loss of genetic diversity in collections. We suggest actions to improve ex situ conservation of exceptional plant species, including developing a central database to aggregate data and track unique individuals of priority threatened species among institutions and adapting a pedigree‐based population management tool that incorporates life‐history aspects unique to plants. If approached collaboratively across regional, national, and global scales, these actions could transform ex situ conservation of threatened plant species.
Aplicación del Modelo Zoológico a la Conservación de Especies Excepcionales de Plantas Amenazadas
Resumen
El mantenimiento de una colección de plantas vivas es el método más común para de conservación ex situ para especies de plantas que no pueden almacenarse en bancos de semillas (i. e., especies excepcionales). La viabilidad de las colecciones vivientes, junto con el valor que representan para los futuros esfuerzo de conservación, puede estar limitada si no existen esfuerzos coordinados para rastrear y manejar a los individuos entre las instituciones. Mediante una estrategia enfocada en el linaje, la comunidad de zoológicos ha establecido una infraestructura interinstitucional que respalda la viabilidad a largo plazo de las poblaciones de animales en cautiverio. Evaluamos la habilidad de esta infraestructura coordinada de metacolecciones para apoyar en la conservación de cuatro especies de plantas curadas en colecciones vivientes en varios jardines botánicos de todo el mundo. Las limitaciones de las prácticas contemporáneas incluyen la incapacidad de recopilar, compartir y analizar los datos de las colecciones de plantas a nivel individual, así como la dificultad de rastrear la procedencia original del material ex situ. El marco de trabajo de metacolecciones coordinadas que utilizan los zoológicos puede ser adoptado por la comunidad botánica para mejorar los resultados de conservación al minimizar la pérdida de la diversidad genética que ocurre en las colecciones. Sugerimos acciones que aumenten la conservación ex situ de las especies excepcionales de plantas. Estas acciones incluyen el desarrollo de una base de datos central para acumular datos y rastrear entre las instituciones a los individuos únicos de las especies amenazadas prioritarias y la adaptación de una herramienta de manejo poblacional basada en el linaje que incorpore los aspectos únicos de la historia de vida de las plantas. Si estas acciones se plantean colaborativamente a escala regional, nacional y global, podrían transformar la conservación ex situ de las especies amenazadas de plantas.
摘要
保存植物活体是对不能贮存种子的植物 (特殊植物) 最常用的迁地保护方法。然而, 如果没有跨机构的生物个体跟踪和管理的协作, 活标本的生存能力及其对未来保护工作的价值可能会受到限制。动物保护团体利用基于系谱的方法建立了一套跨机构的基础工具来支持圈养动物种群的长期生存。本研究评估了这种协作性的聚合采集基础工具在支持保护四种在全球多个植物园存有活标本的植物的能力。结果表明, 当前的保护实践的局限性包括无法在生物个体水平汇编、分享和分析采集植物的数据, 以及难以追踪迁地保护植物的原始种源。植物保护团体可以采用动物园使用的协作性聚合采集框架, 通过减少采集过程中遗传多样性丧失来改善保护结果。我们建议采取行动来推动特殊植物物种的迁地保护, 包括建立中央数据库来收集数据、追踪保护机构优先保护的受威胁物种的每个个体, 以及开发基于系谱的、整合植物特有生活史信息的种群管理工具。如果在区域、国家和全球范围内进行协作, 这些行动将改变濒危植物物种的迁地保护现状。 【翻译: 胡怡思; 审校: 聂永刚】
Article Impact Statement: Using zoo‐style studbooks and pedigree management will be transformative for the conservation of exceptional plants like Brighamia insignis.
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