Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 114
Filtrar
1.
Am J Primatol ; 86(6): e23618, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38482954

RESUMO

Primates are among the most threatened taxa globally, therefore, there is a need to estimate and monitor their populations. Kashmir Gray Langur Semnopithecus ajax is an endangered species for which there is no population estimate. We used double-observer method to estimate its population size in the Kashmir region of North-Western Himalaya. We walked 1284 km across 31 survey blocks spanning all three divisions of Kashmir viz., North, Central, and South Kashmir, covering an area of 411 km2. We counted a minimum of 1367 individual langurs from 27 groups. The detection probability for observer 1 (0.719) and observer 2 (0.656) resulted in a population estimate of 1496 (95% confidence interval [CI] 1367-1899) across 30 groups (with a mean group size of 51), giving a density estimate of 3.64 (3.33-4.62) langurs/km². We found double-observer surveys to be suitable for the population estimation of langurs, and we make recommendations on how to effectively conduct primate surveys, especially in mountainous ecosystems. Our records extend the species distribution range beyond stated by the International Union for Conservation of Nature. Our findings also highlight that the Kashmir Himalaya is a stronghold of the species, where conservation efforts should focus.


Assuntos
Espécies em Perigo de Extinção , Densidade Demográfica , Animais , Índia , Presbytini , Conservação dos Recursos Naturais , Colobinae
2.
J Dairy Sci ; 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38908686

RESUMO

While dairy goat production, characterized by traditional production on small farms, is an important source of income in the Czech Republic and Slovakia, locally adapted breeds have not been fully consolidated over the last 100 years due to large fluctuations in population size and inconsistent breeding programs that allowed for different crossbreeding strategies. Our main objective in this study was therefore to assess the conservation status of 4 Czech (Alpine Goat, White Shorthair, Brown Shorthair and Czech Landrace) and one Slovak (Slovak White Shorthair) local goat breeds, to analyze their population structure and admixture, and to estimate their relatedness to several neighboring breeds. Our analyses included 142 goats belonging to 5 local breeds genotyped with the Illumina 50K BeadChip and 618 previously genotyped animals representing 15 goat breeds from Austria and Switzerland (all analyses based on 46,862 autosomal SNPs and 760 animals). In general, the conservation status of the Czech and Slovak local goat breeds was satisfactory, with the exception of the Brown Shorthair goat, as the analyzed parameters (heterozygosity, haplotype richness, ROH-based inbreeding and effective population size) were mostly above the median of 20 breeds. However, for all 5 Czech and Slovakian breeds, an examination of historical effective population size indicated a substantial decline about 8 to 22 generations ago. In addition, our study revealed that the Czech and Slovakian breeds are not fully consolidated; for instance, White Shorthair and Brown Shorthair were not clearly distinguishable. Considerable admixture, especially in Czech Landrace (effective number of parental clusters equal to 4.2), and low but numerous migration rates from other Austrian and Swiss breeds were found. These results provide valuable insights for future breeding programs and genetic diversity management of local Czech and Slovak goat breeds.

3.
J Fish Biol ; 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38937946

RESUMO

Elasmobranch populations are in steep decline mainly due to overfishing bycatch, but parasites may accelerate the collapse of vulnerable and/or highly parasitized species. We therefore studied metazoan parasites of Rajidae from the northeast Atlantic: vulnerable Leucoraja fullonica, near-threatened Raja brachyura, Raja clavata, Raja microocellata and Raja undulata, and least-concerned Raja montagui and Leucoraja naevus. Overall prevalence varied from 19% for R. montagui to 100% for L. fullonica. Parasite communities differed between skate species, and prevalence and abundance were higher for L. fullonica, R. microocellata, and R. undulata. We recorded 11 parasite taxa in the study: three nematodes, six cestodes, one monogenean, and one myxosporean. Whatever the skate species, the parasite component community comprised at least two nematode taxa among Phocanema spp., Proleptus sp. and Anisakis simplex. DNA-sequencing revealed that Phocanema azarasi and Phocanema krabbei both occurred in R. microocellata and R. undulata. Phocanema spp. was first recorded in L. fullonica, L. naevus, R. microocellata, R. montagui, and R. undulata, as Proleptus sp. in L. fullonica, and A. simplex in L. fullonica and R. clavata, Rockacestus sp. and Nybelinia sp. in R. undulata, and gill-myxosporeans on L. fullonica, L. naevus, R. microocellata, and R. undulata. The occurrence of 16 new host-parasite associations suggests potential environmental changes. Information provided by trophically transmitted helminths confirmed an opportunistic skate diet based on crustaceans and fish. We discuss results in terms of host fitness loss, bioindicator role of parasites, and anisakiasis risk. We recommend incorporating parasitology in research to improve elasmobranch conservation.

4.
Environ Monit Assess ; 196(6): 520, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38713379

RESUMO

Salt marshes pose challenges for the birds that inhabit them, including high rates of nest flooding, tipping, and predation. The impacts of rising sea levels and invasive species further exacerbate these challenges. To assess the urgency of conservation and adequacy of new actions, researchers and wildlife managers may use population viability analyses (PVAs) to identify population trends and major threats. We conducted PVA for Formicivora acutirostris, which is a threatened neotropical bird species endemic to salt marshes. We studied the species' demography in different sectors of an estuary in southern Brazil from 2006 to 2023 and estimated the sex ratio, longevity, productivity, first-year survival, and mortality rates. For a 133-year period, starting in 1990, we modeled four scenarios: (1) pessimistic and (2) optimistic scenarios, including the worst and best values for the parameters; (3) a baseline scenario, with intermediate values; and (4) scenarios under conservation management, with increased recruitment and/or habitat preservation. Projections indicated population decline for all assessment scenarios, with a 100% probability of extinction by 2054 in the pessimistic scenario and no extinction in the optimistic scenario. The conservation scenarios indicated population stability with 16% improvement in productivity, 10% improvement in first-year survival, and stable carrying capacity. The disjunct distribution of the species, with remnants concentrated in a broad interface with arboreal habitats, may seal the population decline by increasing nest predation. The species should be considered conservation dependent, and we recommend assisted colonization, predator control, habitat recovery, and ex situ conservation.


Assuntos
Conservação dos Recursos Naturais , Dinâmica Populacional , Áreas Alagadas , Animais , Brasil , Extinção Biológica , Monitoramento Ambiental/métodos , Espécies em Perigo de Extinção , Aves , Ecossistema
5.
Conserv Biol ; 37(1): e13968, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36073325

RESUMO

The criteria as laid out by the International Union for the Conservation of Nature (IUCN) Red List are the gold standard by which the extinction risk of a species is assessed and where appropriate biological extinctions are declared. However, unlike all other categories, the category of extinct lacks a quantitative framework for assigning this category. Given its subjective nature, we surveyed expert assessors working on a diversity of taxa to explore the attributes they used to declare a species extinct. Using a choice experiment approach, we surveyed 674 experts from the IUCN Species Survival Commission specialist groups and taskforces. Data availability, time from the last sighting, detectability, habitat availability, and population decline were all important attributes favored by assessors when inferring extinction. Respondents with red-listing experience assigned more importance to the attributes data availability, time from the last sighting, and detectability when considering a species extinction, whereas those respondents working with well-known taxa gave more importance to the time from the last sighting. Respondents with no red-listing experience and those working with more well-known taxa (i.e., mammals and birds) were overall less likely to consider species extinct. Our findings on the importance assessors place on attributes used to declare a species extinct provide a basis for informing the development of specific criteria for more accurately assessing species extinctions.


Los criterios establecidos por la Unión Internacional para la Conservación de la Naturaleza (UICN) son la regla de oro con la cual se evalúa el riesgo de extinción de una especie y en donde se declaran las extinciones biológicas. Sin embargo, como con todas las demás categorías, la categoría "extinto" carece de un marco de trabajo cuantitativo para asignar esta categoría. Dada su naturaleza subjetiva, pedimos a los asesores expertos que trabajan con la diversidad de taxones que exploraran los atributos que usan para declarar extinta a una especie. Mediante un experimento de elección, sondeamos a 674 expertos de los grupos especialistas y de trabajo de la Comisión de Supervivencia de Especies de la UICN. La disponibilidad de datos, el tiempo desde la última detección, la detectabilidad, la disponibilidad del hábitat y la declinación poblacional fueron atributos importantes que los asesores favorecieron al inferir las extinciones. Los respondientes con experiencia con la lista roja les asignaron mayor importancia a los atributos de disponibilidad de datos, tiempo desde la última detección y detectabilidad cuando consideraron la extinción de una especie, mientras que los respondientes que trabajan con taxones conocidos le dieron más importancia al tiempo desde la última detección. En general fue menos probable que los respondientes sin experiencia con la lista roja y aquellos que trabajan con los taxones más conocidos (es decir, mamíferos y aves) consideraran extinta a una especie. Nuestros descubrimientos sobre la importancia que los asesores colocan sobre los atributos utilizados para declarar extinta a una especie proporcionan una base para orientar el desarrollo de criterios específicos para evaluar de manera más acertada las extinciones de las especies.


Assuntos
Conservação dos Recursos Naturais , Prova Pericial , Animais , Extinção Biológica , Mamíferos , Ecossistema , Peixes , Espécies em Perigo de Extinção , Biodiversidade
6.
Ecol Lett ; 25(3): 697-707, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35199919

RESUMO

Increases in biodiversity often lead to greater, and less variable, levels of ecosystem functioning. However, whether species are less likely to go extinct in more diverse ecosystems is unclear. We use comprehensive estimates of avian taxonomic, phylogenetic and functional diversity to characterise the global relationship between multiple dimensions of diversity and extinction risk in birds, focusing on contemporary threat status and latent extinction risk. We find that more diverse assemblages have lower mean IUCN threat status despite being composed of species with attributes that make them more vulnerable to extinction, such as large body size or small range size. Indeed, the reduction in current threat status associated with greater diversity far outweighs the increased risk associated with the accumulation of extinction-prone species in more diverse assemblages. Our results suggest that high diversity reduces extinction risk, and that species conservation targets may therefore best be achieved by maintaining high levels of overall biodiversity in natural ecosystems.


Assuntos
Ecossistema , Extinção Biológica , Biodiversidade , Conservação dos Recursos Naturais/métodos , Filogenia
7.
Conserv Biol ; 36(3): e13783, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-34114680

RESUMO

Use of extensive but low-resolution abundance data is common in the assessment of species at-risk status based on quantitative decline criteria under International Union for Conservation of Nature (IUCN) and national endangered species legislation. Such data can be problematic for 3 reasons. First, statistical power to reject the null hypothesis of no change is often low because of small sample size and high sampling uncertainty leading to a high frequency of type II errors. Second, range-wide assessments composed of multiple site-specific observations do not effectively weight site-specific trends into global trends. Third, uncertainty in site-specific temporal trends and relative abundance are not propagated at the appropriate spatial scale. A common result is the propensity to underestimate the magnitude of declines and therefore fail to identify the appropriate at-risk status for a species. We used 3 statistical approaches, from simple to more complex, to estimate temporal decline rates for a designatable unit (DU) of rainbow trout in the Athabasca River watershed in western Canada. This DU is considered a native species for purposes of listing because of its genetic composition characterized as >0.95 indigenous origin in the face of continuing introgressive hybridization with introduced populations in the watershed. Analysis of abundance trends from 57 time series with a fixed-effects model identified 33 sites with negative trends, but only 2 were statistically significant. By contrast, a hierarchical linear mixed model weighted by site-specific abundance provided a DU-wide decline estimate of 16.4% per year and a 3-generation decline of 93.2%. A hierarchical Bayesian mixed model yielded a similar 3-generation decline trend of 91.3% and the posterior distribution showed that the estimate had a >99% probability of exceeding thresholds for an endangered listing. We conclude that the Bayesian approach was the most useful because it provided a probabilistic statement of threshold exceedance in support of an at-risk status recommendation.


El uso de datos extensivos, pero de baja resolución, de la abundancia es una práctica común en la evaluación del estado de riesgo de una especie con base en los criterios cuantitativos de declinación establecidos por la Unión Internacional para la Conservación de la Naturaleza (UICN) y la legislación nacional sobre especies en peligro extinción. Dicha información puede ser problemática por tres razones: primero, el poder estadístico para rechazar la hipótesis nula de ningún cambio es frecuentemente bajo debido a un tamaño pequeño de la muestra y a la elevada incertidumbre del muestreo, lo que resulta en una frecuencia elevada de errores de tipo II; segundo, las evaluaciones de amplia variedad compuestas de varias observaciones específicas de sitio no sopesan efectivamente las tendencias específicas de sitio dentro de las tendencias globales; y tercero, la incertidumbre en las tendencias temporales específicas de sitio y en la abundancia relativa no se propagan a la escala espacial apropiada. Un resultado común del uso de esta información es la propensión a subestimar la magnitud de las declinaciones, y por lo tanto equivocarse en la identificación del estado de riesgo apropiado para la especie. Usamos tres estrategias estadísticas, de simples a más complejas, para estimar las tasas de declinación temporal para una unidad designable (UD) de trucha arcoíris en la cuenca del río Athabasca al oeste de Canadá. Esta UD es considerada una especie nativa por razones de listado debido a su composición genética, caracterizada como >0-95 de origen nativo de frente a la continua hibridación introgresiva con poblaciones introducidas a la cuenca. El análisis de las tendencias de abundancia de 57 series de tiempo con un modelo de efectos fijos identificó 33 sitios con tendencias negativas, pero sólo dos fueron estadísticamente significativas. En contraste, un modelo lineal mixto de jerarquías sopesado por abundancia específica de sitio proporcionó una estimación de declinación en toda la UD de 16.4% año−1 y una declinación a tres generaciones de 93.2%. Un modelo bayesiano de jerarquías produjo una tendencia de declinación a tres generaciones de 91.3% y la distribución posterior mostró que el estimado tuvo una probabilidad >99% de exceder los umbrales para la categorización como especie en peligro. Concluimos que la estrategia bayesiana fue la más útil porque proporcionó una afirmación probabilística de la superación del umbral a favor de una recomendación de categorizar el estado como en riesgo.


Assuntos
Conservação dos Recursos Naturais , Oncorhynchus mykiss , Animais , Teorema de Bayes , Espécies em Perigo de Extinção , Rios
8.
J Fish Biol ; 100(1): 300-314, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34787898

RESUMO

This study investigated aspects of the ornamental fish export trade in Malawi to understand potential impacts of the trade on exploited fish populations in Lake Malawi and recommend measures for management of the ornamental fishery. Information about the ornamental fish export trade in Malawi was sourced from hardcopy file records maintained by the Department of Fisheries between 1998 and December 2019, and semistructured interviews with ornamental fish exporters in Malawi. The information reported in this paper includes ornamental fish capture process and localities of capture within Lake Malawi, the number of ornamental fish exporters, fish export volumes and values in US$ equivalent at 2020 prices, export destinations, temporally shifts in fish collection localities, and the species exported and their conservation status. These results are discussed in relation to the management of the ornamental fishery in Malawi and many recommendations have been proposed relating to the sustainability of the ornamental fishery in Malawi. Since there are many common issues that affect ornamental fisheries worldwide, the findings and recommendations of this study may be applicable for the management of many other ornamental fisheries worldwide.


Assuntos
Pesqueiros , Peixes , Animais , Malaui
9.
Conserv Biol ; 35(2): 502-509, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-32656858

RESUMO

Measuring progress toward international biodiversity targets requires robust information on the conservation status of species, which the International Union for Conservation of Nature (IUCN) Red List of Threatened Species provides. However, data and capacity are lacking for most hyperdiverse groups, such as invertebrates, plants, and fungi, particularly in megadiverse or high-endemism regions. Conservation policies and biodiversity strategies aimed at halting biodiversity loss by 2020 need to be adapted to tackle these information shortfalls after 2020. We devised an 8-point strategy to close existing data gaps by reviving explorative field research on the distribution, abundance, and ecology of species; linking taxonomic research more closely with conservation; improving global biodiversity databases by making the submission of spatially explicit data mandatory for scientific publications; developing a global spatial database on threats to biodiversity to facilitate IUCN Red List assessments; automating preassessments by integrating distribution data and spatial threat data; building capacity in taxonomy, ecology, and biodiversity monitoring in countries with high species richness or endemism; creating species monitoring programs for lesser-known taxa; and developing sufficient funding mechanisms to reduce reliance on voluntary efforts. Implementing these strategies in the post-2020 biodiversity framework will help to overcome the lack of capacity and data regarding the conservation status of biodiversity. This will require a collaborative effort among scientists, policy makers, and conservation practitioners.


Una Estrategia para la Siguiente Década para Enfrentar la Deficiencia de Datos de la Biodiversidad Ignorada Resumen La medida del avance hacia los objetivos internacionales para la biodiversidad requiere información sólida sobre el estado de conservación de las especies, la cual proporciona la Lista Roja de Especies Amenazadas de la Unión Internacional para la Conservación de la Naturaleza (UICN). Sin embargo, los grupos más hiperdiversos, como los invertebrados, las plantas y los hongos, carecen de datos y capacidad, particularmente en regiones megadiversas o de endemismo alto. Las políticas de conservación y las estrategias de biodiversidad dirigidas hacia el cese de la pérdida de biodiversidad para el 2020 necesitan ser adaptadas para solucionar estas insuficiencias de información para después del año 2020. Diseñamos una estrategia de ocho puntos para cerrar las brechas existentes en los datos mediante la reactivación de la investigación exploratoria en el campo sobre la distribución, abundancia y ecología de las especies; la vinculación más cercana entre la investigación taxonómica y la conservación; la mejora a las bases de datos mundiales sobre biodiversidad mediante la presentación obligatoria de datos espacialmente explícitos para las publicaciones científicas; el desarrollo de una base mundial de datos espaciales sobre las amenazas para la biodiversidad para facilitar las valoraciones de la Lista Roja de la UICN; la automatización de las preevaluaciones mediante la integración de datos de distribución y datos de amenazas espaciales; el desarrollo de la capacidad en la taxonomía, la ecología y el monitoreo de la biodiversidad en países con una gran riqueza de especies o endemismos; la creación de programas de monitoreo de especies para los taxones menos conocidos; el desarrollo de suficientes mecanismos de financiamiento para reducir la dependencia de los esfuerzos voluntarios. La implementación de estas estrategias en el marco de trabajo para la biodiversidad posterior al 2020 ayudará a superar la falta de capacidad y datos con respecto al estado de conservación de la biodiversidad. Lo anterior requerirá de un esfuerzo colaborativo entre científicos, formuladores de políticas y practicantes de la conservación.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Animais , Ecologia , Espécies em Perigo de Extinção , Plantas
10.
Ann Bot ; 126(7): 1109-1128, 2020 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-32812638

RESUMO

BACKGROUND AND AIMS: Plants depend fundamentally on establishment from seed. However, protocols in trait-based ecology currently estimate seed size but not seed number. This can be rectified. For annuals, seed number should simply be a positive function of vegetative biomass and a negative function of seed size. METHODS: Using published values of comparative seed number as the 'gold standard' and a large functional database, comparative seed yield and number per plant and per m2 were predicted by multiple regression. Subsequently, ecological variation in each was explored for English and Spanish habitats, newly calculated C-S-R strategies and changed abundance in the British flora. KEY RESULTS: As predicted, comparative seed mass yield per plant was consistently a positive function of plant size and competitive ability, and largely independent of seed size. Regressions estimating comparative seed number included, additionally, seed size as a negative function. Relationships differed numerically between regions, habitats and C-S-R strategies. Moreover, some species differed in life history over their geographical range. Comparative seed yield per m2 was positively correlated with FAO crop yield, and increasing British annuals produced numerous seeds. Nevertheless, predicted values must be viewed as comparative rather than absolute: they varied according to the 'gold standard' predictor used. Moreover, regressions estimating comparative seed yield per m2 achieved low precision. CONCLUSIONS: For the first time, estimates of comparative seed yield and number for >800 annuals and their predictor equations have been produced and the ecological importance of these regenerative traits has been illustrated. 'Regenerative trait-based ecology' remains in its infancy, with work needed on determinate vs. indeterminate flowering ('bet-hedging'), C-S-R methodologies, phylogeny, comparative seed yield per m2 and changing life history. Nevertheless, this has been a positive start and readers are invited to use estimates for >800 annuals, in the Supplementary data, to help advance 'regenerative trait-based ecology' to the next level.


Assuntos
Plantas , Sementes , Ecossistema , Fenótipo , Filogenia
11.
J Fish Biol ; 96(2): 539-542, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31823370

RESUMO

Here we present records of sharks obtained using baited remote underwater stereo-video systems (stereo-BRUVS) at two Brazilian oceanic islands. Fourteen of the 60 deployments recorded 19 sharks in Trindade Island. In Saint Peter and Saint Paul Archipelago (SPSPA), two pelagic and two demersal deployments recorded two and one shark, respectively, including the locally extinct Galapagos shark Carcharhinus galapagensis. Stereo-BRUVS should be considered as adjuncts to other non-invasive methods to monitor shark populations.


Assuntos
Tubarões/fisiologia , Animais , Oceano Atlântico , Brasil , Conservação dos Recursos Naturais , Extinção Biológica , Ilhas , Densidade Demográfica , Especificidade da Espécie , Telemetria
12.
Mol Ecol ; 28(22): 4914-4925, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31597210

RESUMO

Genomic diversity is the evolutionary foundation for adaptation to environmental change and thus is essential to consider in conservation planning. Island species are ideal for investigating the evolutionary drivers of genomic diversity, in part because of the potential for biological replicates. Here, we use genome data from 180 individuals spread among 27 island populations from 17 avian species to study the effects of island area, body size, demographic history and conservation status on contemporary genomic diversity. Our study expands earlier work on a small number of neutral loci to the entire genome and from a few species to many. We find significant positive correlation between island size and genomic diversity, a significant negative correlation between body size and genomic diversity, and that historical population declines significantly reduced contemporary genomic diversity. Our study shows that island size is the key factor in determining genomic diversity, indicating that habitat conservation is key to maintaining adaptive potential in the face of global environmental change. We found that threatened species generally had a significantly smaller values of Watterson's theta (θW  = 4Ne µ) compared to nonthreatened species, suggesting that θW may be useful as a conservation indicator for at-risk species. Overall, these findings (a) provide biological insights into how genomic diversity scales with ecological, morphological and demographic factors; and (b) illustrate how population genomic data can be leveraged to better inform conservation efforts.


Assuntos
Tamanho Corporal/genética , Tentilhões/genética , Genoma/genética , Adaptação Fisiológica/genética , Animais , Evolução Biológica , Demografia/métodos , Fluxo Gênico/genética , Genômica/métodos , Ilhas
13.
Conserv Biol ; 33(6): 1380-1391, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-30950112

RESUMO

Understanding threats acting on marine organisms and their conservation status is vital but challenging given a paucity of data. We studied the cumulative human impact (CHI) on and conservation status of seahorses (Hippocampus spp.)-a genus of rare and data-poor marine fishes. With expert knowledge and relevant spatial data sets, we built linear-additive models to assess and map the CHI of 12 anthropogenic stressors on 42 seahorse species. We examined the utility of indices of estimated impact (impact of each stressor and CHI) in predicting conservation status for species with random forest (RF) models. The CHI values for threatened species were significantly higher than those for nonthreatened species (category based on International Union for Conservation of Nature Red List). We derived high-accuracy RF models (87% and 96%) that predicted that 5 of the 17 data-deficient species were threatened. Demersal fishing practices with high bycatch and pollution were the best predictors of threat category. Major threat epicenters were in China, Southeast Asia, and Europe. Our results and maps of CHI may help guide global seahorse conservation and indicate that modeling and mapping human impacts can reveal threat patterns and conservation status for data-poor species. We found that for exploring threat patterns of focal species, species-level CHI models are better than existing ecosystem-level CHI models.


Uso de Modelos de Impacto Humano Acumulativo para Revelar los Patrones de Amenaza Mundial para Hipocampos Resumen El entendimiento de las amenazas que actúan sobre los organismos marinos y su estado de conservación es de suma importancia pero a la vez un gran reto debido a la insuficiencia de datos. Estudiamos el estado de conservación y el impacto humano acumulativo (CHI, en inglés) que existe sobre los hipocampos (Hippocampus spp.)- un género de peces marinos raro y escaso de datos. Construimos modelos lineales aditivos con el conocimiento de expertos y conjuntos de datos espaciales relevantes para evaluar y mapear el CHI de los doce estresantes antropogénicos que afectan a las 42 especies de hipocampos. Examinamos la utilidad que tienen los índices de impacto estimado (el impacto de cada estresante y cada CHI) para la predicción del estado de conservación de las especies usando modelos de bosque azaroso (RF, en inglés). Los valores del CHI para las especies amenazadas fueron considerablemente más altos que aquellos obtenidos para las especies no amenazadas (categoría basada en la Lista Roja de la Unión Internacional para la Conservación de la Naturaleza). De esto derivamos modelos RF de alta certeza (87% y 96%), los cuales pronosticaron que cinco de las 17 especies deficientes de datos estaban amenazadas. Las prácticas de pesca demersal con una captura accesoria elevada y la contaminación fueron los mejores pronosticadores de la categoría de amenaza. Los principales epicentros de amenaza se ubicaron en China, el sureste asiático y en Europa. Nuestros resultados y mapas de CHI pueden ayudar a guiar la conservación mundial de hipocampos y también indican que el modelado y el mapeo de de los impactos humanos pueden revelar los patrones de amenaza y el estado de conservación de las especies deficientes de datos. Descubrimos que para explorar los patrones de amenaza de especies focales, son mejores los modelos de CHI a nivel de especie que los ya existentes modelos de CHI a nivel de ecosistema.


Assuntos
Ecossistema , Smegmamorpha , Animais , China , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Europa (Continente) , Humanos
14.
Environ Monit Assess ; 191(2): 79, 2019 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-30652197

RESUMO

Natural and anthropogenic pressures are major concerns about the stability of vegetation in protected areas of the Sudano-Sahelian regions. This study aims to describe the woody flora of Mozogo-Gokoro National Park, submitted to these geographical area constraints in the Far North of Cameroon. Global inventory of this flora is carried out, through three collection units representing strata in vegetation that are previously identified by photo-interpretation, with analyses focusing on compositional diversity parameters. Results show a very rich woody flora (110 woody plant species, for 46 genera and 30 families), having a quasi-typical Sudano-Sahelian physiognomy. Vegetation is mainly a shrubby dry forest, dominated by species such as Senegalia ataxacantha, Anogeissus leiocarpa, Tamarindus indica, Psorospermum senegalense, Clerodendrum capitatum, Celtis toka, and the botanical families of Fabaceae and Combretaceae. The diversity indices, the woody density, and the basal area are high (4.32 bits for the Shannon-Weaver index, 2694.16 stems/ha and 43.89 m2/ha). Despite the dominance of Sahelian individuals, the importance of Sudanian and Guinean species (more than 22.68% of species) brings vegetation closer to those of much humid areas. In wooded savanna collection unit, several values of the evaluated parameters are lower in comparison with those obtained in the two others. However, these fluctuations related to the degradation of vegetation are insignificant, indicating a preserved resilience. The Mozogo-Gokoro National Park stands as a model of plant conservation in the Sudano-Sahelian zone in Cameroon, hence the major interest to be granted for its conservation and sustainable management.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Parques Recreativos , Plantas/classificação , Camarões , Ecossistema , Dinâmica Populacional
15.
Conserv Biol ; 32(6): 1290-1300, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-29790214

RESUMO

Lack of demographic data for most of the world's threatened species is a widespread problem that precludes viability-based status assessments for species conservation. A commonly suggested solution is to use data from species that are closely related or biologically similar to the focal species. This approach assumes similar species and populations of the same species have similar demographic rates, an assumption that has yet to be thoroughly tested. We constructed a Bayesian hierarchical model with data on 425 plant species to predict demographic rates (intrinsic rate of population growth, recruit survival, juvenile survival, adult survival, and fecundity) based on biological traits and phylogenetic relatedness. Generally, we found small effects of species-level traits (except woody polycarpic species tended to have high adult survival rates that increased with plant height) and a weak phylogenetic signal for 4 of the 5 demographic parameters examined. Patterns were stronger in adult survival and fecundity than other demographic rates; however, the unexplained variances at both the species and population levels were high for all demographic rates. For species lacking demographic data, our model produced large, often inaccurate, prediction intervals that may not be useful in a management context. Our findings do not support the assumption that biologically similar or closely related species have similar demographic rates and provide further evidence that direct monitoring of focal species and populations is necessary for informing conservation status assessments.


Assuntos
Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Animais , Teorema de Bayes , Demografia , Filogenia
16.
New Phytol ; 213(4): 1618-1624, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27864957

RESUMO

Contents 1618 I. 1618 II. 1619 III. 1620 IV. 1623 1623 References 1624 SUMMARY: Understanding the forces that shape the great amount of variation in plant longevity, reproductive output and growth rate is fundamental to effective predictions of viability, invasions and evolutionary pressures. Here, I extend the recently introduced 'fast-slow continuum and reproductive strategy' framework to quantify the variation in plant life history strategies world-wide. I use high-resolution demographic information from 625 plant species and show that this framework predicts not only key demographic properties, such as population growth rate and demographic resilience, but also has important connections to the leaf economics spectrum, biogeographical characteristics, evolutionary biology and conservation biology. This framework may allow plant biologists to unlock powerful global plant predictions from a handful of open-access field measurements.


Assuntos
Desenvolvimento Vegetal , Dinâmica Populacional , Análise de Componente Principal , Reprodução
17.
Glob Chang Biol ; 23(8): 3030-3039, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28452164

RESUMO

Colour polymorphisms have played a major role in enhancing current understanding of how selection and demography can impact phenotypes. Because different morphs often display alternative strategies and exploit alternative ecological niches, colour polymorphism can be expected to promote adaptability to environmental changes. However, whether and how it could influence populations' and species' response to global changes remains debated. To address this question, we built an up-to-date and complete database on avian colour polymorphism based on the examination of available data from all 10,394 extant bird species. We distinguished between true polymorphism (where different genetically determined morphs co-occur in sympatry within the same population) and geographic variation (parapatric or allopatric colour variation), because these two patterns of variation are expected to have different consequences on populations' persistence. Using the IUCN red list, we then showed that polymorphic bird species are at lesser risk of extinction than nonpolymorphic ones, after controlling for a range of factors such as geographic range size, habitat breadth, life history, and phylogeny. This appears consistent with the idea that high genetic diversity and/or the existence of alternative strategies in polymorphic species promotes the ability to adaptively respond to changing environmental conditions. In contrast, polymorphic species were not less vulnerable than nonpolymorphic ones to specific drivers of extinction such as habitat alteration, direct exploitation, climate change, and invasive species. Thus, our results suggest that colour polymorphism acts as a buffer against environmental changes, although further studies are now needed to understand the underlying mechanisms. Developing accurate quantitative indices of sensitivity to specific threats is likely a key step towards a better understanding of species response to environmental changes.


Assuntos
Aves , Mudança Climática , Cor , Extinção Biológica , Animais , Ecossistema , Polimorfismo Genético
18.
Conserv Biol ; 31(3): 581-591, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-27976421

RESUMO

Small body size is generally correlated with r-selected life-history traits, including early maturation, short-generation times, and rapid growth rates, that result in high population turnover and a reduced risk of extinction. Unlike other classes of vertebrates, however, small freshwater fishes appear to have an equal or greater risk of extinction than large fishes. We explored whether particular traits explain the International Union for Conservation of Nature (IUCN) Red List conservation status of small-bodied freshwater fishes from 4 temperate river basins: Murray-Darling, Australia; Danube, Europe; Mississippi-Missouri, North America; and the Rio Grande, North America. Twenty-three ecological and life-history traits were collated for all 171 freshwater fishes of ≤120 mm total length. We used generalized linear mixed-effects models to assess which combination of the 23 traits best explained whether a species was threatened or not threatened. We used the best models to predict the probability of 29 unclassified species being listed as threatened. With and without controlling for phylogeny at the family level, small body size-among small-bodied species-was the most influential trait correlated with threatened species listings. The k-folds cross-validation demonstrated that body size and a random effect structure that included family predicted the threat status with an accuracy of 78% (SE 0.5). We identified 10 species likely to be threatened that are not listed as such on the IUCN Red List. Small body size is not a trait that provides universal resistance to extinction, particularly for vertebrates inhabiting environments affected by extreme habitat loss and fragmentation. We hypothesize that this is because small-bodied species have smaller home ranges, lower dispersal capabilities, and heightened ecological specialization relative to larger vertebrates. Trait data and further model development are needed to predict the IUCN conservation status of the over 11,000 unclassified freshwater fishes, especially those under threat from proposed dam construction in the world's most biodiverse river basins.


Assuntos
Conservação dos Recursos Naturais , Extinção Biológica , Peixes , Animais , Austrália , Tamanho Corporal , Ecossistema , Espécies em Perigo de Extinção , Europa (Continente) , América do Norte
19.
J Fish Biol ; 90(1): 3-38, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27785814

RESUMO

The name killifish refers to the oviparous secondary freshwater fishes in the order Cyprinodontiformes. Killifishes are abundant in Mexico and are represented by four extant families, Rivulidae, Profundulidae, Fundulidae and Cyprinodontidae, comprising > 50 species in a wide variety of habitats. This paper reviews the current classification of the killifishes of Mexico, as well as aspects of their distribution, biology, ecology and current population conservation status.


Assuntos
Biodiversidade , Peixes Listrados/classificação , Peixes Listrados/fisiologia , Distribuição Animal , Animais , Ecologia , México , Filogenia , Densidade Demográfica , Especificidade da Espécie
20.
Adv Mar Biol ; 73: 157-92, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26790892

RESUMO

Australian humpback dolphins (Sousa sahulensis) were recently described as a new species endemic to northern Australia and potentially southern New Guinea. We assessed the species conservation status against IUCN Red List Criteria using available information on their biology, ecology and threatening processes. Knowledge of population sizes and trends across the species range is lacking. Recent genetic studies indicate Australian humpback dolphins live in small and relatively isolated populations with limited gene flow among them. The available abundance estimates range from 14 to 207 individuals and no population studied to date is estimated to contain more than 104 mature individuals. The Potential Biological Removal method indicates populations are vulnerable to even low rates of anthropogenic mortality. Habitat degradation and loss is ongoing and expected to increase across the species range in Australia, and a continuing decline in the number of mature individuals is anticipated. Considering the available evidence and following a precautionary approach, we considered this species as Vulnerable under IUCN criterion C2a(i) because the total number of mature individuals is plausibly fewer than 10,000, an inferred continuing decline due to cumulative impacts, and each of the populations studied to date is estimated to contain fewer than 1000 mature individuals. Ongoing research efforts and recently developed research strategies and priorities will provide valuable information towards the future conservation and management of Australian humpback dolphins.


Assuntos
Conservação dos Recursos Naturais , Golfinhos/classificação , Golfinhos/fisiologia , Espécies em Perigo de Extinção , Distribuição Animal , Migração Animal , Animais , Austrália , Comportamento Animal/fisiologia , Ecossistema , Dinâmica Populacional , Comportamento Social , Especificidade da Espécie
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA