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1.
Proc Natl Acad Sci U S A ; 119(4)2022 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-35042806

RESUMO

Globally, 15,521 animal species are listed as threatened by the International Union for the Conservation of Nature, and of these less than 3% have genomic resources that can inform conservation management. To combat this, global genome initiatives are developing genomic resources, yet production of a reference genome alone does not conserve a species. The reference genome allows us to develop a suite of tools to understand both genome-wide and functional diversity within and between species. Conservation practitioners can use these tools to inform their decision-making. But, at present there is an implementation gap between the release of genome information and the use of genomic data in applied conservation by conservation practitioners. In May 2020, we launched the Threatened Species Initiative and brought a consortium of genome biologists, population biologists, bioinformaticians, population geneticists, and ecologists together with conservation agencies across Australia, including government, zoos, and nongovernment organizations. Our objective is to create a foundation of genomic data to advance our understanding of key Australian threatened species, and ultimately empower conservation practitioners to access and apply genomic data to their decision-making processes through a web-based portal. Currently, we are developing genomic resources for 61 threatened species from a range of taxa, across Australia, with more than 130 collaborators from government, academia, and conservation organizations. Developed in direct consultation with government threatened-species managers and other conservation practitioners, herein we present our framework for meeting their needs and our systematic approach to integrating genomics into threatened species recovery.


Assuntos
Conservação dos Recursos Naturais/métodos , Espécies em Perigo de Extinção/legislação & jurisprudência , Genômica/normas , Animais , Coleta de Dados , Espécies em Perigo de Extinção/tendências , Genoma , Genômica/legislação & jurisprudência , Genômica/métodos , Governo
2.
Emerg Infect Dis ; 30(6): 1125-1132, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38781928

RESUMO

During October 2022, enteric redmouth disease (ERM) affected Chinese sturgeons at a farm in Hubei, China, causing mass mortality. Affected fish exhibited characteristic red mouth and intestinal inflammation. Investigation led to isolation of a prominent bacterial strain, zhx1, from the internal organs and intestines of affected fish. Artificial infection experiments confirmed the role of zhx1 as the pathogen responsible for the deaths. The primary pathologic manifestations consisted of degeneration, necrosis, and inflammatory reactions, resulting in multiple organ dysfunction and death. Whole-genome sequencing of the bacteria identified zhx1 as Yersinia ruckeri, which possesses 135 drug-resistance genes and 443 virulence factor-related genes. Drug-susceptibility testing of zhx1 demonstrated high sensitivity to chloramphenicol and florfenicol but varying degrees of resistance to 18 other antimicrobial drugs. Identifying the pathogenic bacteria associated with ERM in Chinese sturgeons establishes a theoretical foundation for the effective prevention and control of this disease.


Assuntos
Doenças dos Peixes , Peixes , Yersiniose , Yersinia ruckeri , Yersiniose/veterinária , Yersiniose/microbiologia , Yersiniose/epidemiologia , Animais , China/epidemiologia , Doenças dos Peixes/microbiologia , Doenças dos Peixes/epidemiologia , Yersinia ruckeri/genética , Peixes/microbiologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Testes de Sensibilidade Microbiana , Sequenciamento Completo do Genoma , Farmacorresistência Bacteriana
3.
BMC Plant Biol ; 24(1): 465, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38807074

RESUMO

Davidia involucrata is a woody perennial and the only living species in the Genus Davidia. It is native to southern China where it holds cultural and scientific importance. However, D. involucrata is now an endangered species and its natural range includes low pH soils which are increasingly impacted by acid rain, nitrogen deposition and imbalanced nutrient cycling. The combination of these stresses also poses the additional risk of aluminum (Al) toxicity. Since the responses of D. involucrata to low pH and aluminum toxicity have not been investigated previously, a hydroponic experiment was conducted to examine the growth of one year old D. involucrata saplings after 50 d growth in a range of pH and Al conditions. Plant biomass, morphology, antioxidant enzyme activity, mineral concentrations and plant ecological strategy were compared at pH 5.8 and pH 4.0 without added Al (AlCl3) and in 0.1, 0.2 and 0.5 mM Al at pH 4.0. Our results showed that compared with pH 5.8, pH 4.0 (without added Al) not only inhibited root and shoot growth but also limited accumulation of nitrogen (N) and phosphorus (P) in leaves of D. involucrate. However, low Al concentrations (0.1 and 0.2 mM Al) at pH 4.0 partially restored the aboveground growth and leaf N concentrations, suggesting an alleviation of H+ toxicity by low Al concentrations. Compared with low Al concentrations, 0.5 mM Al treatment decreased plant growth and concentrations of N, P, and magnesium (Mg) in the leaves, which demonstrated the toxicity of high Al concentration. The results based on plant ecological strategy showed that D. involucrate decreased the competitiveness and favored its stress tolerance as pH changed from 5.8 to 4.0. Meanwhile, the competitiveness and stress tolerance of D. involucrata increased and decreased at low Al concentrations, respectively, and decreased and increased at high Al concentration, respectively. These trade-offs in ecological strategy were consistent with the responses of growth and antioxidant enzyme activity, reflecting a sensitive adaptation of D. involucrata to acid and Al stresses, which may aid in sustaining population dynamics. These findings are meaningful for understanding the population dynamics of D. involucrata in response to aluminum toxicity in acid soils.


Assuntos
Alumínio , Alumínio/toxicidade , Concentração de Íons de Hidrogênio , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Fósforo/metabolismo , Solo/química , Nitrogênio/metabolismo , Biomassa
4.
BMC Plant Biol ; 24(1): 486, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38822268

RESUMO

BACKGROUND: Horsfieldia hainanensis Merr., an indicator species of China's humid tropical rainforests, is endangered due to difficulties with population regeneration. In this study, the biological characteristics and germination adaptability of the seeds were studied for the first time, in order to provide a basis for analyzing the causes of endangerment and strategies for the artificial cultivation of H. hainanensis. The effects of biological characteristics (population, arils, seed coat, seed weight, seed moisture content) and environmental factors (temperature, light, drought, substrate, burial depth) on seed germination and seedling growth of H. hainanensis were studied. RESULTS AND DISCUSSION: The fruits were found to be capsules containing seeds wrapped in a pericarp and fleshy aril, which provide protection and assist in seed dispersal, but also pose risks to the seeds, as the peel and fleshy aril can become moldy under high temperature and humidity conditions. There were significant differences in fruit morphology and germination characteristics among different populations, and the seed quality of populations in Niandian village, Daxin County, Chongzuo City, Guangxi Zhuang Autonomous Region was better. The arils significantly inhibited seed germination, the germination of large seeds was better, and seedling growth from medium seeds was superior. H. hainanensis seeds were sensitive to dehydration, and intolerant to drought and low temperature, which is typical of recalcitrant seeds. The seeds are suitable for germination on a moist substrate surface with good water retention and breathability at 30-35℃.


Assuntos
Espécies em Perigo de Extinção , Germinação , Sementes , Germinação/fisiologia , Sementes/crescimento & desenvolvimento , Sementes/fisiologia , China , Frutas/crescimento & desenvolvimento , Frutas/fisiologia , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Temperatura
5.
BMC Plant Biol ; 24(1): 1016, 2024 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-39465373

RESUMO

BACKGROUND: The genus Robinsonia DC. (tribe Senecioneae, Asteraceae) endemic to the Juan Fernández Islands in Chile is one of the most conspicuous insular plant groups in the world. Unlike typical herbaceous Asteraceae plants, these plants demonstrate spectacular and unusual rosette tree growth forms as shown by the alpine giant senecios (genus Dendrosenecio, tribe Senecioneae) endemic to the East African mountains. However, monophyly of the genus and phylogenetic relationships among species of Robinsonia as well as their plastome evolution remain elusive. This study aims to explore their phylogeny, species diversification, and molecular evolution based on the complete plastome sequences in the context of adaptive radiation on oceanic islands. RESULTS: The insular Robinsonia plastomes are highly conserved in their structures and organization of contents. Five divergence hotspots as potential chloroplast markers and five positively selected coding genes (accD, ndhF, rpoA, ycf1, and ycf2) are identified. Robinsonia plastomes has an overall nucleotide diversity higher than that of the sky island Dendrosenecio, but much lower than herbaceous Senecio. Phylogenetic analysis demonstrates the monophyly of Robinsonia and identifies two major infrageneric lineages. Both Robinsonia and Dendrosenecio are deeply nested within large genus Senecio. CONCLUSIONS: While plastid genomes of Robinsonia are highly conserved, their sequences strongly demonstrated the monophyly of the genus and inferred robust interspecific relationships, including herbaceous Senecio and woody Dendrosenecio. Different sets of positively selected chloroplast genes, five for Robinsonia and two for Dendrosenecio, may play an important role in the adaptation strategies of these fascinating woody species in insular and continental sky island habitats. Overall phylogenetic positions and sister lineages of Robinsonia and Dendrosenecio require additional study based on broader sampling of Senecio.


Assuntos
Asteraceae , Evolução Molecular , Filogenia , Plastídeos , Asteraceae/genética , Plastídeos/genética , Chile , Genomas de Plastídeos , Ilhas
6.
Proc Biol Sci ; 291(2018): 20240314, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38471549

RESUMO

North Atlantic right whales are Critically Endangered and declining, with entanglements in fishing gear a key contributor to their decline. Entanglement events can result in lethal and sub-lethal (i.e. increased energetic demands and reduced foraging ability) impacts, with the latter influencing critical life-history states, such as reproduction. Using a multi-event framework, we developed a Bayesian mark-recapture model to investigate the influence of entanglement severity on survival and recruitment for female right whales. We used information from 199 known-aged females sighted between 1977 and 2018, combined with known entanglements of varying severity that were classified as minor, moderate or severe. Severe entanglements resulted in an average decline in survival of 27% for experienced non-breeders, 9% for breeders and 26% for pre-breeding females compared with other entanglements and unentangled individuals. Surviving individuals with severe entanglements had low transitional probabilities to breeders, but surprisingly, individuals with minor entanglements had the lowest transitional probabilities, contrary to expectations underpinning current management actions. Management actions are needed to address the lethal and sub-lethal impacts of entanglements, regardless of severity classification.


Assuntos
Reprodução , Baleias , Humanos , Animais , Feminino , Idoso , Teorema de Bayes , Cruzamento , Oceano Atlântico
7.
Mol Ecol ; 33(19): e17533, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39262289

RESUMO

Habitat fragmentation reduces gene flow, causing genetic differentiation and diversity loss in endangered species through genetic drift and inbreeding. However, the impact of habitat fragmentation on ectomycorrhizal (ECM) fungi remains unexplored, despite their critical roles in forest ecosystems. Here, we investigated the population genetic structure and the demographic history of Rhizopogon togasawarius, the ECM fungus specifically colonizing the host tree Pseudotsuga japonica, across its entire distribution range (>200 km). These two species are designated as endangered species on the IUCN Red List since they are found only in small, fragmented forests in Japan. We analysed 236 R. togasawarius individuals from five remaining populations across the Kii Peninsula and the Shikoku Island, separated by a sea channel. Simple sequence repeat analyses using 20 loci revealed strong genetic differentiation among populations (FST = 0.255), even significant in the nearest population pair separated by a distance of only 8 km (FST = 0.075), indicating extremely limited gene flow between populations. DIYABC-RF analyses implied that population divergence occurred approximately 6000 generations ago between the two regions, and nearly 1500 generations ago between the nearest populations within Shikoku Island, related to past climate events. Because of prolonged genetic isolation, significant inbreeding was confirmed in four of five populations, where effective population sizes became very small (Ne = 9.0-58.0). Although evaluation of extinction risks for microorganisms is challenging, our conservation genetic results indicated that habitat fragmentation increases extinction risk through population genetic mechanisms, and therefore should not be overlooked in biodiversity conservation efforts.


Assuntos
Ecossistema , Espécies em Perigo de Extinção , Fluxo Gênico , Genética Populacional , Repetições de Microssatélites , Micorrizas , Pseudotsuga , Micorrizas/genética , Micorrizas/classificação , Japão , Repetições de Microssatélites/genética , Pseudotsuga/microbiologia , Pseudotsuga/genética , Variação Genética
8.
Ecol Appl ; 34(4): e2965, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38629596

RESUMO

Habitat loss is affecting many species, including the southern mountain caribou (Rangifer tarandus caribou) population in western North America. Over the last half century, this threatened caribou population's range and abundance have dramatically contracted. An integrated population model was used to analyze 51 years (1973-2023) of demographic data from 40 southern mountain caribou subpopulations to assess the effectiveness of population-based recovery actions at increasing population growth. Reducing potential limiting factors on threatened caribou populations offered a rare opportunity to identify the causes of decline and assess methods of recovery. Southern mountain caribou abundance declined by 51% between 1991 and 2023, and 37% of subpopulations were functionally extirpated. Wolf reduction was the only recovery action that consistently increased population growth when applied in isolation, and combinations of wolf reductions with maternal penning or supplemental feeding provided rapid growth but were applied to only four subpopulations. As of 2023, recovery actions have increased the abundance of southern mountain caribou by 52%, compared to a simulation with no interventions. When predation pressure was reduced, rapid population growth was observed, even under contemporary climate change and high levels of habitat loss. Unless predation is reduced, caribou subpopulations will continue to be extirpated well before habitat conservation and restoration can become effective.


Assuntos
Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Rena , Animais , Rena/fisiologia , Conservação dos Recursos Naturais/métodos , Modelos Biológicos , Dinâmica Populacional , Lobos/fisiologia , Ecossistema
9.
Am J Bot ; 111(5): e16322, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38641895

RESUMO

PREMISE: Functional traits reflect species' responses to environmental variation and the breadth of their ecological niches. Fagus grandifolia and Oreomunnea mexicana have restricted distribution in upper montane cloud forests (1700-2000 m a.s.l.) in Mexico. These species were introduced into plantings at lower elevations (1200-1600 m a.s.l.) that have climates predicted for montane forests in 2050 and 2070. The aim was to relate morphological leaf traits to the ecological niche structure of each species. METHODS: Leaf functional traits (leaf area, specific leaf area [SLA], thickness, and toughness) were analyzed in forests and plantings. Atmospheric circulation models and representative concentration pathways (RCPs: 2.6, 4.5, 8.5) were used to assess future climate conditions. Trait-niche relationships were analyzed by measuring the Mahalanobis distance (MD) from the forests and the plantings to the ecological niche centroid (ENC). RESULTS: For both species, leaf area and SLA were higher and toughness lower in plantings at lower elevation relative to those in higher-elevation forests, and thickness was similar. Leaf traits varied with distance from sites to the ENC. Forests and plantings have different environmental locations regarding the ENC, but forests are closer (MD 0.34-0.58) than plantings (MD 0.50-0.70) for both species. CONCLUSIONS: Elevation as a proxy for expected future climate conditions influenced the functional traits of both species, and trait patterns related to the structure of their ecological niches were consistent. The use of distances to the ENC is a promising approach to explore variability in species' functional traits and phenotypic responses in optimal versus marginal environmental conditions.


Assuntos
Mudança Climática , Fagus , Florestas , Folhas de Planta , Folhas de Planta/fisiologia , Folhas de Planta/anatomia & histologia , Fagus/fisiologia , Fagus/anatomia & histologia , México , Ecossistema
10.
J Med Primatol ; 53(3): e12714, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38822430

RESUMO

Callithrix aurita is an endangered small primate endemic to the Atlantic Forest. The present work reports the labor of a free-living C. aurita, through observation of its length and offspring viability. A conservative treatment was used to maintain fetal viability, in view of the species conservation importance.


Assuntos
Callithrix , Animais , Brasil , Feminino , Gravidez , Espécies em Perigo de Extinção , Conservação dos Recursos Naturais
11.
Conserv Biol ; 38(4): e14261, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38571408

RESUMO

Amid a global infrastructure boom, there is increasing recognition of the ecological impacts of the extraction and consumption of construction minerals, mainly processed as concrete, including significant and expanding threats to global biodiversity. We investigated how high-level national and international biodiversity conservation policies address mining threats, with a special focus on construction minerals. We conducted a review and quantified the degree to which threats from mining these minerals are addressed in biodiversity goals and targets under the 2011-2020 and post-2020 biodiversity strategies, national biodiversity strategies and action plans, and the assessments of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. Mining appeared rarely in national targets but more frequently in national strategies. Yet, in most countries, it was superficially addressed. Coverage of aggregates mining was greater than coverage of limestone mining. We outline 8 key components, tailored for a wide range of actors, to effectively mainstream biodiversity conservation into the extractive, infrastructure, and construction sectors. Actions include improving reporting and monitoring systems, enhancing the evidence base around mining impacts on biodiversity, and modifying the behavior of financial agents and businesses. Implementing these measures could pave the way for a more sustainable approach to construction mineral use and safeguard biodiversity.


Amenazas de la minería a las políticas de alto nivel para la conservación de la biodiversidad Resumen Enmedio del auge global del desarrollo de infraestructura, hay un mayor reconocimiento de los impactos ecológicos de la extracción y consumo de materiales para construcción, procesados predominantemente como concreto. Estos materiales representan amenazas significativas y en expansión para la biodiversidad global. Investigamos cómo son abordadas las amenazas de la minería por las políticas nacionales e internacionales de alto nivel para la conservación de la biodiversidad, con enfoque especial en los minerales para construcción. Realizamos una revisión exhaustiva y cuantificamos el grado en el cual son abordadas las amenazas de la extracción de estos minerales en los objetivos y metas para la biodiversidad bajo estrategias 2011­2020 y post 2020, las estrategias y planes de acción nacionales para la biodiversidad, y las evaluaciones de la Plataforma Intergubernamental Científico­normativa sobre Diversidad Biológica y Servicios de los Ecosistemas. La minería raramente apareció en los objetivos nacionales, pero fue más frecuente en las estrategias nacionales. Sin embargo, fue abordada superficialmente en la mayoría de los países. La cobertura de minería de agregados fue mayor que la cobertura de la minería de caliza. Describimos ocho componentes clave, adaptados para una amplia gama de actores, para incorporar eficazmente la conservación de la biodiversidad en los sectores extractivo, desarrollo de infraestructura y construcción. Las acciones incluyen la mejora de los sistemas de informes y monitoreo, el reforzamiento de la base de evidencias en torno a los impactos de la minería sobre la biodiversidad y la modificación del comportamiento de los agentes financieros y comerciales. La implementación de estas medidas podría allanar el camino para un enfoque más sostenible en el uso de minerales para la construcción y la salvaguarda de la biodiversidad.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Política Ambiental , Mineração , Conservação dos Recursos Naturais/métodos , Política Ambiental/legislação & jurisprudência
12.
Conserv Biol ; 38(2): e14190, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37768181

RESUMO

The fundamental goal of a rare plant translocation is to create self-sustaining populations with the evolutionary resilience to persist in the long term. Yet, most plant translocation syntheses focus on a few factors influencing short-term benchmarks of success (e.g., survival and reproduction). Short-term benchmarks can be misleading when trying to infer future growth and viability because the factors that promote establishment may differ from those required for long-term persistence. We assembled a large (n = 275) and broadly representative data set of well-documented and monitored (7.9 years on average) at-risk plant translocations to identify the most important site attributes, management techniques, and species' traits for six life-cycle benchmarks and population metrics of translocation success. We used the random forest algorithm to quantify the relative importance of 29 predictor variables for each metric of success. Drivers of translocation outcomes varied across time frames and success metrics. Management techniques had the greatest relative influence on the attainment of life-cycle benchmarks and short-term population trends, whereas site attributes and species' traits were more important for population persistence and long-term trends. Specifically, large founder sizes increased the potential for reproduction and recruitment into the next generation, whereas declining habitat quality and the outplanting of species with low seed production led to increased extinction risks and a reduction in potential reproductive output in the long-term, respectively. We also detected novel interactions between some of the most important drivers, such as an increased probability of next-generation recruitment in species with greater seed production rates, but only when coupled with large founder sizes. Because most significant barriers to plant translocation success can be overcome by improving techniques or resolving site-level issues through early intervention and management, we suggest that by combining long-term monitoring with adaptive management, translocation programs can enhance the prospects of achieving long-term success.


Identificación de pronosticadores del éxito de reubicación en especies raras de plantas Resumen El objetivo fundamental de la reubicación de plantas raras es la creación de poblaciones autosuficientes con resiliencia evolutiva que persistan a la larga. De todas maneras, la mayoría de las síntesis de estas reubicaciones se enfocan en unos cuantos factores que influyen sobre los parámetros a corto plazo del éxito (supervivencia y reproducción). Los parámetros a corto plazo pueden ser engañosos si se intenta inferir el crecimiento y la viabilidad en el futuro ya que los factores que promueven el establecimiento pueden diferir de aquellos requeridos para la persistencia a largo plazo. Ensamblamos un conjunto grande de datos representativos en general (n = 275) de las reubicaciones de plantas en riesgo bien documentadas y monitoreadas (7.9 años en promedio) para identificar los atributos de sitio más importantes, las técnicas de manejo y los rasgos de las especies para seis parámetros de ciclos de vida y medidas poblacionales del éxito de reubicación. Usamos el algoritmo de bosque aleatorio para cuantificar la importancia relativa de las 29 variables de pronosticadores para cada medida del éxito. Los factores en los resultados de las reubicaciones variaron con los marcos temporales y las medidas de éxito. Las técnicas de manejo tuvieron la mayor influencia relativa sobre la obtención de parámetros de ciclos de vida y tendencias poblacionales a corto plazo, mientras que los atributos de sitio y los rasgos de la especie fueron más importantes para la persistencia poblacional y las tendencias a largo plazo. En específico, las grandes cantidades de fundadores incrementaron el potencial de reproducción y reclutamiento de la siguiente generación, mientras que la declinación de la calidad del hábitat incrementó el riesgo de extinción y el trasplante de especies con baja producción de semillas redujo el rendimiento del potencial reproductivo a la larga. También detectamos interacciones novedosas entre algunos de los factores más importantes, como el aumento en la probabilidad del reclutamiento en la siguiente generación en especies con tasas mayores de producción de semillas, pero sólo cuando se emparejó con grandes cantidades de fundadores. Ya que las barreras más significativas para el éxito de la reubicación de plantas pueden superarse al mejorar las técnicas o resolver los temas a nivel de sitio por medio de un manejo y una intervención temprana, sugerimos que con la combinación del monitoreo a largo plazo con el manejo adaptativo los programas de reubicación pueden aumentar el prospecto de lograr el éxito a largo plazo.


Assuntos
Conservação dos Recursos Naturais , Plantas , Conservação dos Recursos Naturais/métodos , Reprodução , Sementes , Ecossistema
13.
Conserv Biol ; : e14292, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38752470

RESUMO

To achieve sustainable shark fisheries, it is key to understand not only the biological drivers and environmental consequences of overfishing, but also the social and economic drivers of fisher behavior. The extinction risk of sharks is highest in coastal tropical waters, where small-scale fisheries are most prevalent. Small-scale fisheries provide a critical source of economic and nutritional security to coastal communities, and these fishers are among the most vulnerable social and economic groups. We used Kenya's and Zanzibar's small-scale shark fisheries, which are illustrative of the many data-poor, small-scale shark fisheries worldwide, as case studies to explore the relationship between extinction risk and the economic and nutritional value of sharks. To achieve this, we combined existing data on shark landings, extinction risk, and nutritional value with sales data at 16 key landing sites and information from interviews with 476 fishers. Shark fisheries were an important source of economic and nutritional security, valued at >US$4 million annually and providing enough nutrition for tens of thousands of people. Economically and nutritionally, catches were dominated by threatened species (72.7% and 64.6-89.7%, respectively). The most economically valuable species were large and slow to reproduce (e.g. mobulid rays, wedgefish, and bull, silky, and mako sharks) and therefore more likely to be threatened with extinction. Given the financial incentive and intensive fishing pressure, small-scale fisheries are undoubtedly major contributors to the decline of threatened coastal shark species. In the absence of effective fisheries management and enforcement, we argue that within small-scale fisheries the conditions exist for an economically incentivized feedback loop in which vulnerable fishers are driven to persistently overfish vulnerable and declining shark species. To protect these species from extinction, this feedback loop must be broken.


Conexión entre el riesgo de extinción y el valor nutricional de los tiburones en las pesquerías a pequeña escala Resumen Para lograr la sustentabilidad de las pesquerías de tiburones se deben entender los factores ecológicos y las consecuencias ambientales de la sobrepesca, así como los factores sociales y económicos del comportamiento del pescador. El riesgo de extinción de los tiburones es mucho mayor en las aguas tropicales costeras, en donde son más frecuentes las pesquerías a pequeña escala. Las pesquerías a pequeña escala, que además se encuentran entre los grupos con mayor vulnerabilidad social y económica, proporcionan una fuente importante de seguridad económica y nutricional para las comunidades costeras. Usamos las pesquerías de Kenia y Zanzíbar, las cuales representan muy bien a muchas de las pequeñas pesquerías de tiburones con deficiencia de datos, como estudios de caso para explorar la relación entre el riesgo de extinción y el valor económico y nutricional de los tiburones. Para lograr esto, combinamos los datos ya existentes de desembarques de tiburones, riesgo de extinción y valor nutricional con la información de ventas en 16 sitios clave de desembarque e información de las entrevistas a 476 pescadores. Las pesquerías de tiburones son una fuente importante de seguridad alimentaria y económica, valorada en más de US$4 millones anuales y que proporciona suficiente alimentación para miles de personas. En cuanto a la economía y la alimentación, las capturas estuvieron dominadas por especies amenazadas (72.7% y 64.6­89.7%, respectivamente). Las especies con mayor valor económico eran aquellas de gran tamaño y lenta reproducción, y, por lo tanto, con mayor probabilidad de estar en peligro de extinción. A causa del incentivo económico y la presión intensa de pesca, las pesquerías pequeñas sin duda son uno de los principales contribuyentes a la declinación de especies amenazadas de tiburones en las costas. Ya que no hay una aplicación ni un manejo efectivos de las pesquerías, argumentamos que en las pequeñas pesquerías existen las condiciones para un bucle de retroalimentación con incentivación económica en el que los pescadores vulnerables con frecuencia necesitan sobre pescar las especies de tiburones vulnerables y en declinación. Para proteger a estas especies de la extinción, este bucle de retroalimentación debe romperse.

14.
Conserv Biol ; : e14391, 2024 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-39417626

RESUMO

Academic review, promotion, and tenure processes place a premium on frequent publication in high-impact factor (IF) journals. However, conservation often relies on species-specific information that is unlikely to have the broad appeal needed for high-IF journals. Instead, this information is often distributed in low-IF, taxa- and region-specific journals. This suggests a potential mismatch between the incentives for academic researchers and the scientific needs of conservation implementation. To explore this mismatch, we looked at federal implementation of the United States Endangered Species Act (ESA), which requires the use of the "best available science" to list a species as endangered or threatened and thus receive powerful legal protections. In assessing the relationship between academic sources of this "best available science" and ESA implementation, we looked at the 13,292 sources (e.g., academic journals, books, reports, regulations, personal communications, etc.) cited by the second Obama administration (2012-2016) across all ESA listings. We compared the IFs of all 4836 journals that published peer-reviewed papers cited in these listings against their citation frequency in ESA listings to determine whether a journal's IF varied in proportion with its contribution to federal conservation. Most of the peer-reviewed academic articles referenced in ESA listings came from low-IF or no-IF journals that tended to focus on specific taxa or regions. Although we support continued attention to cutting-edge, multidisciplinary science for its ability to chart new pathways and paradigms, our findings stress the need to value and fund the taxa- and region-specific science that underpins actionable conservation laws.


El papel de las revistas con factor de impacto bajo en la implementación de la conservación Resumen Los procesos de revisión académica, promoción y titularidad otorgan primas a la publicación frecuente en revistas con factor de impacto (FI) alto. Sin embargo, la conservación depende mucho de la información específica por especie, que es poco probable que tenga el atractivo necesario para las revistas de FI alto. En lugar de esto, esta información se distribuye con frecuencia en revistas de FI bajo, específicas para la región y ciertos taxones. Esto sugiere una desigualdad potencial entre los incentivos para los investigadores académicos y las necesidades científicas de la implementación de la conservación. Exploramos esta desigualdad mediante la implementación federal de la Ley de Especies en Peligro de Extinción de Estados Unidos (ESA), la cual requiere que se use la "mejor ciencia disponible" para enlistar a una especie como en peligro o amenazada para que así reciba una protección legal sólida. Durante el análisis de la relación entre las fuentes académicas de esta "mejor ciencia disponible" y la implementación de la ESA, revisamos 13,292 fuentes (revistas académicas, libros, reportes, regulaciones, comunicación personal, etc.) citadas en la segunda administración del presidente Obama (2012 ­ 2016) en todos los listados de la ESA. Comparamos los FI de las 4, 836 revistas que publicaron artículos revisados por pares y citados en estos listados con la frecuencia de citas en los listados de la ESA para determinar si el FI de una revista varía en proporción a su contribución para la conservación federal. La mayoría de estos artículos referenciados en los listados de la ESA provenían de revistas con FI bajo o sin FI que tendían a enfocarse en regiones o taxones específicos. Aunque apoyamos la atención continua para la ciencia multidisciplinaria e innovadora por su capacidad de generar nuevos caminos y paradigmas, nuestros hallazgos resaltan la necesidad de valorar y financiar la ciencia específica por taxones y regiones que apuntala las leyes procesables de conservación.

15.
Conserv Biol ; : e14370, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39225270

RESUMO

Expert judgment underpins assessment of threatened ecosystems. However, experts are often narrowly defined, and variability in their judgments may be substantial. Models built from structured elicitation with large diverse expert panels can contribute to more consistent and transparent decision-making. We conducted a structured elicitation under a broad definition of expertise to examine variation in judgments of ecosystem viability and collapse in a critically endangered ecosystem. We explored whether variation in judgments among 83 experts was related to affiliation and management expertise and assessed performance of an average model based on common ecosystem indicators. There were systematic differences among individuals, much of which were not explained by affiliation or expertise. However, of the individuals affiliated with government, those in conservation and environmental departments were more likely to determine a patch was viable than those in agriculture and rural land management. Classification errors from an average model, in which all individuals were weighted equally, were highest among government agriculture experts (27%) and lowest among government conservation experts (12%). Differences were mostly cases in which the average model predicted a patch was viable but the individual thought it was not. These differences arose primarily for areas that were grazed or cleared of mature trees. These areas are often the target of restoration, but they are also valuable for agriculture. These results highlight the potential for conflicting advice and disagreement about policies and actions for conserving and restoring threatened ecosystems. Although adoption of an average model can improve consistency of ecosystem assessment, it can fail to capture and convey diverse opinions held by experts. Structured elicitation and models of ecosystem viability play an important role in providing data-driven evidence of where differences arise among experts to support engagement and discussion among stakeholders and decision makers and to improve the management of threatened ecosystems.


Análisis de los modelos de opiniones de expertos para informar la evaluación de la viabilidad y el colapso ambiental Resumen La evaluación de los ecosistemas amenazados se basa en la opinión de los expertos. Sin embargo, la definición de experto suele ser limitada y la variabilidad de sus juicios puede ser considerable. Los modelos elaborados a partir de consultas estructuradas con grupos de expertos amplios y diversos pueden contribuir a una toma de decisiones más coherente y transparente. Realizamos una consulta estructurada con una definición amplia de experto para analizar la variación en los juicios sobre la viabilidad y el colapso de un ecosistema en peligro crítico. Exploramos si la variación en los juicios entre 83 expertos estaba relacionada con la afiliación y la experiencia en gestión y evaluamos el rendimiento de un modelo medio basado en indicadores comunes del ecosistema. Observamos diferencias sistemáticas entre los expertos, gran parte de las cuales no se explicaban por la afiliación o la experiencia. Sin embargo, entre los expertos vinculados a la administración pública, los de los departamentos de conservación y medio ambiente tenían más probabilidades de determinar que una parcela era viable que los de agricultura y gestión de tierras rurales. Los errores de clasificación de un modelo medio con todos los individuos ponderados por igual, fueron mayores entre los expertos gubernamentales en agricultura (27%) y menores entre los expertos gubernamentales en conservación (12%). En la mayoría de los casos, las diferencias se debían a que el modelo medio predecía que una parcela era viable, pero el individuo pensaba que no lo era. Estas diferencias surgieron sobre todo en zonas que habían sido pastoreadas o con una tala total de árboles maduros. Estas zonas suelen ser objeto de restauración, pero también son valiosas para la agricultura. Estos resultados ponen de manifiesto la posibilidad de que se produzcan consejos contradictorios y desacuerdos sobre las políticas y acciones de conservación y restauración de los ecosistemas pastoreados y forestales. Si bien la adopción de un modelo medio puede mejorar la coherencia de la evaluación de los ecosistemas, también puede fallar a la hora de captar y transmitir las diversas opiniones de los expertos. Las consultas estructuradas y los modelos de viabilidad de los ecosistemas desempeñan un papel importante a la hora de aportar pruebas basadas en datos de dónde surgen las diferencias entre los expertos para apoyar el compromiso y el debate entre las partes interesadas y los responsables de la toma de decisiones, así como para mejorar la gestión de los ecosistemas amenazados.

16.
Conserv Biol ; 38(5): e14358, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39248733

RESUMO

Monitoring wildlife trade dynamics is an important initial step for conservation action and demand reduction campaigns to reduce illegal wildlife trade. Studies often rely on one data source to assess a species' trade, such as seizures or the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) trade data. Each database provides useful information but is often incomplete. Combining information from multiple sources helps provide a more complete understanding of trade. A recent rapid increase in demand for helmeted hornbill (Rhinoplax vigil) casques (a brightly colored, solid keratinous rostrum) led to its uplisting to critically endangered on the International Union for Conservation of Nature Red List in 2015. However, there is little current information on what factors influence trade trends and what current levels of demand are. We combined data from CITES, seizure records, and previously underused, yet abundant, art and antique auction data to examine the global trade in helmeted hornbill casque products (HHPs). Three decades of auction data revealed that 1027 individual HHPs had been auctioned since 1992; total auction sales were over US$3 million from 1992 to 2021. The number of HHPs auctioned was greatest from 2011 to 2014, just after the global art boom (2009-2011), followed by a decline in volume and price. The auction data also revealed 2 possible markets for HHPs: true antique and speculative, defined by era, price, and trade patterns. Trends in illegal trade matched those of the auction market, but legal trade remained consistently low. Combining data sources from legal, illegal, and gray markets provided an overview of the dynamics of illegal trade in an endangered species. This approach can be applied to other wildlife markets to provide a more complete understanding of trade and demand at the market level to inform future demand reduction campaigns.


Análisis del comercio ornamental legal, ilegal y gris del cálao con casco, especie en peligro crítico Resumen El monitoreo de la dinámica del comercio de especies silvestres es un paso inicial importante para las acciones de conservación y las campañas de reducción de la demanda destinadas a reducir el comercio ilegal de especies silvestres. Los estudios suelen basarse en una sola fuente de datos para evaluar el comercio de una especie, como las incautaciones o los datos comerciales de la Convención sobre el Comercio Internacional de Especies Amenazadas de Fauna y Flora Silvestres (CITES). Cada base de datos proporciona información útil, pero a menudo incompleta. La combinación de información procedente de varias fuentes ayuda a comprender mejor el comercio. Un reciente y rápido aumento de la demanda de cascos (un casquete queratinoso, sólido y de colores brillantes) de cálao con casco (Rhinoplax vigil) hizo que en 2015 se incluyera en la Lista Roja de la Unión Internacional para la Conservación de la Naturaleza como especie en peligro crítico. Sin embargo, existe poca información actual sobre los factores que influyen en las tendencias del comercio y cuáles son los niveles actuales de demanda. Combinamos datos de CITES, registros de incautaciones y datos de subastas de arte y antigüedades previamente poco utilizados, aunque abundantes, para examinar el comercio mundial de productos de casquetes de cálao con casco (CCC). Tres décadas de datos de subastas revelaron que se habían subastado 1,027 CCC individuales desde 1992; las ventas totales en subasta superaron los tres millones de dólares entre 1992 y 2021. El número de CCC subastados fue mayor entre 2011 y 2014, justo después del boom del arte (2009­2011), seguido de un descenso en volumen y precio. Los datos de las subastas también revelaron dos posibles mercados para los CCC: el de las verdaderas antigüedades y el especulativo, definidos por la época, el precio y los patrones de comercio. Las tendencias del comercio ilegal coincidieron con las del mercado de subastas, pero el comercio legal se mantuvo bajo con constancia. Con la combinación de fuentes de datos de mercados legales, ilegales y grises, nuestros datos proporcionaron una visión general de la dinámica del comercio ilegal de una especie amenazada. Este enfoque puede aplicarse a otros mercados de especies silvestres para obtener un conocimiento más completo del comercio y la demanda a nivel de mercado que sirva de base a futuras campañas de reducción de la demanda.


Assuntos
Comércio , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Espécies em Perigo de Extinção/legislação & jurisprudência , Conservação dos Recursos Naturais/legislação & jurisprudência , Animais , Comércio/legislação & jurisprudência , Crime/prevenção & controle
17.
Conserv Biol ; 38(5): e14339, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39248763

RESUMO

Environmental regulations restricting the use of a natural resource or species often have unintended consequences. One example is prohibitions on the international trade in culturally important endangered wildlife. Trade restrictions may artificially increase scarcity and, consequently, value. In China, international trade restrictions may trigger bouts of speculative investment that have the opposite effect of the restrictions' intent. We examined how China's speculative economy and cultural history have together led to unintended consequences when regulating wildlife trade. In China, wildlife markets occupy a legal gray area that can make regulations ineffectual or even counterproductive. In extreme cases, prohibiting trade can provoke market booms. Further unintended consequences include potential cultural backlash. In China and across the Global South, international trade restrictions are sometimes considered a continuation of a longstanding history of Western intervention and thus may not be enforced as strongly or may generate resentment. This pushback has contributed to rising calls to decolonialize conservation and may lead to growing alliances between China and other Global South countries when negotiating international wildlife trade restrictions in the future.


Especulación financiera y herencia cultural en los mercados de fauna de China Resumen Las regulaciones ambientales que restringen el uso de un recurso natural o una especie suelen tener consecuencias accidentales. Un ejemplo son las prohibiciones para el mercado internacional de fauna en peligro con importancia cultural. Las restricciones pueden incrementar de manera artificial la escasez y, como consecuencia, el valor. En China, las restricciones internacionales del mercado pueden detonar episodios de inversión especulativa que tienen el efecto opuesto a lo que se pretende con las restricciones. Analizamos cómo la economía especulativa y la historia cultural de China han, en conjunto, derivado en consecuencias accidentales cuando se regula el mercado de fauna. En este país, los mercados de fauna ocupan un área legal gris que puede volver ineficaces a las regulaciones o incluso contraproducentes. En casos extremos, prohibir el mercado puede provocar un auge de este. Otra consecuencia accidental es el potencial rechazo cultural. En China y en todo el Sur Global, algunas veces se consideran las restricciones del mercado internacional como una continuación de la historia de intervenciones occidentales y por lo tanto puede que no se apliquen con tanta fuerza o que generen resentimiento. Esta resistencia ha contribuido al incremento de llamados para descolonizar la conservación y podría llevar al aumento de alianzas entre China y otros países del Sur Global cuando se negocien restricciones para el mercado internacional de fauna en el futuro.


Assuntos
Animais Selvagens , Comércio , Conservação dos Recursos Naturais , China , Conservação dos Recursos Naturais/legislação & jurisprudência , Conservação dos Recursos Naturais/economia , Animais , Espécies em Perigo de Extinção , Cultura
18.
Conserv Biol ; 38(2): e14200, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37817673

RESUMO

Preemptive conservation efforts to reduce threats have been credited with precluding the need to list some imperiled species under the U.S. Endangered Species Act (ESA). Such efforts can result in outcomes where species are conserved and regulatory costs associated with ESA listing are avoided. Yet, the extent and type of conservation effort involved in achieving preclusion from listing are not well understood. We quantified the attributes of conservation efforts identified as important for 43 species whose preclusion from listing was attributed to conservation efforts, as described in U.S. Federal Register documents that report the decisions not to list. We considered 2 features of preemptive conservation: effort applied (measured as the number of conservation initiatives) and number of conservation partners involved. We also quantified the type and location of conservation actions. We found a mean of 4.3 initiatives (range 1-22) and 8.2 partners (range 1-31) documented per precluded species; both measures of conservation effort were significantly and positively associated with the species' range area and the proportion of private land across its range. The number of initiatives was also positively related to the number of threats affecting a species. Locations of conservation actions varied; more species had actions on public land than on private land (p = 0.003). Numbers of species with restorative actions (e.g., invasive species control) were similar to numbers with prohibitive actions. Our findings highlight relationships between species' context and preemptive conservation activities, providing a first cross-species analysis of conservation efforts for species that were precluded from listing under the ESA due to conservation.


Atributos de los esfuerzos preventivos de conservación para las especies excluidas del listado de la Ley de Especies en Peligro de Extinción de Estados Unidos Resumen A los esfuerzos preventivos de conservación para reducir las amenazas se les atribuye la exclusión de algunas especies en peligro de la lista de la Ley de Especies en Peligro de Extinción de los Estados Unidos (ESA, en inglés). Dichos esfuerzos pueden tener resultados en los que se protegen las especies y se evitan los costos regulatorios asociados con el listado de la ESA, pero no se sabe mucho sobre el alcance y el tipo de esfuerzo de conservación involucrados en la exclusión del listado. Cuantificamos los atributos de los esfuerzos de conservación identificados como importantes para 43 especies cuya exclusión del listado fue atribuida a los esfuerzos de conservación, descrito así en los documentos del Registro Federal de los EUA que reportan las razones para no incluirlas en la lista. Consideramos dos características de la conservación preventiva: el esfuerzo aplicado (medido como el número de iniciativas de conservación) y el número de socios de conservación involucrados. También cuantificamos el tipo y ubicación de las acciones de conservación. Obtuvimos una media de 4.3 iniciativas (rango 1­22) y 8.2 socios (rango 1­31) documentados por especie excluida; ambas medidas del esfuerzo de conservación tuvieron una asociación significativa y positiva con el área de distribución de la especie y la proporción de suelo privado en esta distribución. El número de iniciativas también tuvo una relación positiva con el número de amenazas para las especies. Las ubicaciones de las acciones de conservación variaron y más especies contaban con acciones en suelo público que en suelo privado (p = 0.003). El número de especies que contaban con acciones de restauración (p. ej.: control de especies invasoras) fue similar a aquellas con acciones prohibitivas. Nuestros hallazgos resaltan la relación entre el contexto de la especie y las actividades preventivas de conservación, lo que proporciona un primer análisis entre especies de los esfuerzos de conservación para especies excluidas de la ESA por cuestiones de conservación.


Assuntos
Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Animais , Espécies Introduzidas
19.
Conserv Biol ; 38(4): e14243, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38433373

RESUMO

Wildlife conservation depends on supportive social as well as biophysical conditions. Social identities such as hunter and nonhunter are often associated with different attitudes toward wildlife. However, it is unknown whether dynamics within and among these identity groups explain how attitudes form and why they differ. To investigate how social identities help shape wildlife-related attitudes and the implications for wildlife policy and conservation, we built a structural equation model with survey data from Montana (USA) residents (n = 1758) that tested how social identities affect the relationship between experiences with grizzly bears (Ursus arctos horribilis) and attitudes toward the species. Model results (r2 = 0.51) demonstrated that the hunter identity magnified the negative effect of vicarious property damage on attitudes toward grizzly bears (ß = -0.381, 95% confidence interval [CI]: -0.584 to -0.178, p < 0.001), which in turn strongly influenced acceptance (ß = -0.571, 95% CI: -0.611 to -0.531, p < 0.001). Our findings suggested that hunters' attitudes toward grizzly bears likely become more negative primarily because of in-group social interactions about negative experiences, and similar group dynamics may lead nonhunters to disregard the negative experiences that out-group members have with grizzly bears. Given the profound influence of social identity on human cognitions and behaviors in myriad contexts, the patterns we observed are likely important in a variety of wildlife conservation situations. To foster positive conservation outcomes and minimize polarization, management strategies should account for these identity-driven perceptions while prioritizing conflict prevention and promoting positive wildlife narratives within and among identity groups. This study illustrates the utility of social identity theory for explaining and influencing human-wildlife interactions.


La influencia de la identidad social sobre la actitud hacia la fauna Resumen La conservación de la fauna depende de condiciones de apoyo tanto sociales como biofísicas. La identidad social, como ser cazador o no, con frecuencia está asociada a las diferentes actitudes hacia la fauna. Sin embargo, no sabemos si las dinámicas dentro y entre estos grupos de identidad explican cómo las actitudes se forman y porqué son diferentes. Construimos un modelo de ecuación estructural con información de encuestas realizadas a 1,758 residentes de Montana (Estados Unidos) para conocer cómo la identidad social ayuda a formar la actitud relacionada con la fauna y las implicaciones que tiene para la conservación y políticas de fauna. El modelo analizó cómo la identidad social afecta la relación entre las experiencias con osos pardos (Ursus arctos horribilis) y la actitud hacia la especie. Los resultados del modelo (r2 = 0.51) demostraron que la identidad de cazador aumentaba el efecto negativo del daño indirecto a la propiedad sobre la actitud hacia los osos (ß=­0.381, 95% CI ­0.584 a ­0.178, p<0.001), lo cual en cambio tenía una gran influencia sobre la aceptación (ß=­0.571, 95% CI ­0.611 a ­0.531, p<0.001). Nuestros descubrimientos sugieren que la actitud de los cazadores hacia los osos probablemente se vuelve más negativa principalmente debido a las interacciones sociales del endogrupo en torno a las experiencias negativas; las dinámicas similares pueden llevar a los no cazadores a menospreciar las experiencias negativas que los miembros del exogrupo han tenido con los osos. Dada la influencia profunda que tiene la identidad social sobre la cognición humana y el comportamiento en una miríada de contextos, los patrones que observamos probablemente sean importantes en una variedad de situaciones de conservación de fauna. Para promover los resultados positivos de conservación y minimizar la polarización, las estrategias de manejo deberían considerar estas percepciones influenciadas por la identidad mientras se prioriza la prevención de conflictos y se promueven narrativas positivas de fauna dentro y entre los grupos de identidad. Este estudio demuestra la utilidad que tiene la teoría de identidad social para explicar e influenciar las interacciones humano­fauna.


Assuntos
Atitude , Conservação dos Recursos Naturais , Identificação Social , Ursidae , Animais , Ursidae/psicologia , Ursidae/fisiologia , Montana , Humanos , Animais Selvagens/psicologia
20.
Parasitology ; 151(3): 300-308, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38212980

RESUMO

A 30 years long data series on the infection dynamics of European eel (Anguilla anguilla L.) with the non-native invasive nematode Anguillicola crassus Kuwahara, Niimi & Hagaki, 1974 is presented. Parasite burden was evaluated for 30 years in inland and coastal waters in Mecklenburg-Western Pomerania from 1991 to 2020. The total prevalence, mean intensity and damage status of the swim bladders were very high during the first decade (1991­2000), and significantly decreased in both marine and freshwater eel populations in the following decades (2001­2010, 2011­2020). The parasite intensity of eels in coastal waters was significantly lower compared with the freshwater systems (61.3% vs 79.5% in the first decade), indicating the vulnerability of the parasites to brackish water conditions and the fact that the life cycle of A. crassus cannot be completed under high saline conditions. Eel caught in the western part of the Baltic Sea (west of Darss sill) had the lowest mean infection (51.8% in first decade) compared to the eastern part with 63.8%. Thus, besides different infection patterns caused by the environmental conditions, a temporal trend towards a reduced parasite intensity and a more balanced parasite­host relationship developed in the 30 years of interaction after the first invasion. Possible reasons and mechanisms for the observed trends in parasite­host interactions are discussed.


Assuntos
Anguilla , Dracunculoidea , Doenças dos Peixes , Animais , Anguilla/parasitologia , Sacos Aéreos/parasitologia , Estágios do Ciclo de Vida , Alemanha/epidemiologia , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/parasitologia
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