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2.
Rev. biol. trop ; 71(1)dic. 2023.
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1449521

RESUMEN

Introduction: Worldwide, expanding human activities continue to be a threat to many large-bodied species, including jaguars. As these activities continue, it is critical to understand how home range sizes will be impacted by human-modified landscapes. Objective: To evaluate the importance of protected and unprotected land on home-range size across their range. Methods: We used home range data from 117 jaguars in several habitat protection categories and human biome types. We used a Generalized Linear Mixed Model to test home range and spatial overlap with conservation categories and human biomes. Results: Most home-ranges were in Jaguar Conservation Units (62 %), followed by Protected Areas (21 %), Indigenous People's Lands (10 %) and Jaguar Movement Corridors (3 %), where 76 % of the jaguars lived inside one the first three conservation types. However, outside of conserved land, Rangeland, Cropland, Seminatural land and other human biomes were also important (24 % of the individuals). Jaguars in Rangeland, Cropland and Seminatural land had the largest home ranges. Conclusions: Although conservation land was dominant, human-impacted lands appear to play a considerable role in satisfying the spatial requirements of jaguars.


Introducción: A nivel mundial, la expansión de actividades humanas continúa teniendo un riesgo para muchas especies de cuerpo grande, tal como los jaguares. Conforme continúen estas actividades, es crucial entender el impacto de paisajes modificados sobre el tamaño de su territorio. Objetivo: Evaluar la importancia de terrenos protegidos y no protegidos sobre el tamaño de su territorio a lo largo de su rango. Métodos: Usamos datos de tamaño de los territorios de 117 jaguares en varias categorías de protección de hábitats y biomas humanos. Usamos un Modelo Mixto Lineal Generalizado para probar traslapes espaciales y de territorios con categorías de conservación y biomas humanos. Resultados: La mayoría de los territorios estaban en Unidades de Conservación de Jaguares (62 %), seguido por Áreas protegidas (21 %), Tierras de Pueblos Indígenas (10 %) y Corredores de Movimiento de Jaguares (3 %), en donde el 76 % de los jaguares vivían dentro de alguna de las primeras tres modalidades de conservación. Sin embargo, fuera de áreas protegidas, pastizales, tierras de cultivo, terrenos seminaturales y otros biomas humanos también fueron importantes (24 % de individuos). Jaguares en pastizales, tierras de cultivo, y terrenos seminaturales tuvieron territorios más grandes. Conclusiones: Aunque las áreas de conservación fueron dominantes, áreas con impacto humano parecieron jugar un rol considerable en satisfacer los requerimientos espaciales de los jaguares.

3.
Proc Natl Acad Sci U S A ; 120(39): e2306987120, 2023 09 26.
Artículo en Inglés | MEDLINE | ID: mdl-37722053

RESUMEN

Mass extinctions during the past 500 million y rapidly removed branches from the phylogenetic tree of life and required millions of years for evolution to generate functional replacements for the extinct (EX) organisms. Here we show, by examining 5,400 vertebrate genera (excluding fishes) comprising 34,600 species, that 73 genera became EX since 1500 AD. Beyond any doubt, the human-driven sixth mass extinction is more severe than previously assessed and is rapidly accelerating. The current generic extinction rates are 35 times higher than expected background rates prevailing in the last million years under the absence of human impacts. The genera lost in the last five centuries would have taken some 18,000 y to vanish in the absence of human beings. Current generic extinction rates will likely greatly accelerate in the next few decades due to drivers accompanying the growth and consumption of the human enterprise such as habitat destruction, illegal trade, and climate disruption. If all now-endangered genera were to vanish by 2,100, extinction rates would be 354 (average) or 511 (for mammals) times higher than background rates, meaning that genera lost in three centuries would have taken 106,000 and 153,000 y to become EX in the absence of humans. Such mutilation of the tree of life and the resulting loss of ecosystem services provided by biodiversity to humanity is a serious threat to the stability of civilization. Immediate political, economic, and social efforts of an unprecedented scale are essential if we are to prevent these extinctions and their societal impacts.


Asunto(s)
Ecosistema , Extinción Biológica , Animales , Humanos , Filogenia , Efectos Antropogénicos , Biodiversidad , Mamíferos
4.
PLoS One ; 17(8): e0267589, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35930545

RESUMEN

Conservation biogeography, which applies principles, theories, and analyses of biodiversity distribution patterns to address conservation challenges, can provide valuable insight and guidance to policy making for protection of biodiversity at multiple scales. The temperate and tropical ecosystems of the Nearctic-Neotropical transition in the small western state of Colima, Mexico, support a mosaic of remarkably diverse fauna and flora and provide a rare opportunity to determine spatial distribution patterns of terrestrial vertebrate species, assess human-induced threats, and identify potential conservation strategies. We analyzed the spatial distribution patterns and correlated them with the current land cover and extent of the protected areas. Despite its limited geographic extension, 29% (866) of all vertebrates, and almost a quarter of both endemic and threatened species in Mexico, live in Colima. Our analysis identified clear high-richness concentration sites (i.e., "hotspots") coincident for all groups and that elevation and both temperate and tropical ecosystems composition exert significant influence on richness patterns. Furthermore, current species´ distribution also showed significant correlation with natural and disturbed landcover. Significant hotspots for all species groups coincided poorly with the limited protected areas in the state (only 3.8%). The current state of natural land cover (less than 16%) in the state, coupled with its remarkable biological importance, highlights the need for further complementary conservation efforts including expansion and creation of new protected areas, significant restoration efforts and other conservation measures to maintain this uniquely biogeographic and biological diverse region of the country.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Animales , Biodiversidad , Humanos , México , Vertebrados
6.
Philos Trans R Soc Lond B Biol Sci ; 377(1857): 20210378, 2022 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-35757873

RESUMEN

Humanity has triggered the sixth mass extinction episode since the beginning of the Phanerozoic. The complexity of this extinction crisis is centred on the intersection of two complex adaptive systems: human culture and ecosystem functioning, although the significance of this intersection is not properly appreciated. Human beings are part of biodiversity and elements in a global ecosystem. Civilization, and perhaps even the fate of our species, is utterly dependent on that ecosystem's proper functioning, which society is increasingly degrading. The crisis seems rooted in three factors. First, relatively few people globally are aware of its existence. Second, most people who are, and even many scientists, assume incorrectly that the problem is primarily one of the disappearance of species, when it is the existential threat of myriad population extinctions. Third, while concerned scientists know there are many individual and collective steps that must be taken to slow population extinction rates, some are not willing to advocate the one fundamental, necessary, 'simple' cure, that is, reducing the scale of the human enterprise. We argue that compassionate shrinkage of the human population by further encouraging lower birth rates while reducing both inequity and aggregate wasteful consumption-that is, an end to growthmania-will be required. This article is part of the theme issue 'Ecological complexity and the biosphere: the next 30 years'.


Asunto(s)
Ecosistema , Extinción Biológica , Biodiversidad , Humanos
7.
Med Vet Entomol ; 36(3): 371-380, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35481550

RESUMEN

We examined tick communities on wild felid hosts in three ecoregions of Mexico. We collected 186 ticks of 7 species from 10 pumas (Puma concolor) and 9 jaguars (Panthera onca). Tick community composition varied across the ecoregions, and across host species within each region. Overall, Ixodes affinis, Amblyomma ovale, and Amblyomma tenellum were the most abundant species; however, only the latter two ticks were distributed across all three ecoregions, while I. affinis, along with Ixodes spinipalpis, Amblyomma inornatum, and Amblyomma parvum were restricted to more limited geographical regions. Ixodes affinis occurred strictly in southern tropical rainforest ecoregions and was significantly more abundant in Selva Lacandona compared with the Yucatán Peninsula. Amblyomma ovale was significantly more common in the tropical dry forest in the Pacific coastal ecoregion. Amblyomma tenellum abundance tended to be higher on jaguars, while I. affinis abundance was higher on pumas. Regional distribution patterns of some tick species (e.g., I. affinis and I. spinipalpis) may be determined by off-host environmental conditions rather than host factors. In contrast, at the local scale, occurrence and abundance of some tick species (e.g., A. tenellum, A. ovale and Rhipicephalus microplus) might be driven by ecological-host factors, such as habitat use or predator-prey relationships.


Asunto(s)
Ixodes , Panthera , Puma , Animales , México/epidemiología , Simpatría
8.
J Mammal ; 103(2): 255-274, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35422678

RESUMEN

Specimens of the Peromyscus boylii species group distributed in the western and northeastern montane regions of Michoacán, México, historically have been assigned to P. levipes. Previous studies indicated that these specimens possessed mitochondrial DNA haplotypes that were distinct from both P. levipes and P. kilpatricki, a recently named species in the P. boylii species group from northeastern Michoacán and western Morelos. Herein karyotypic, DNA sequence, and morphological data were analyzed from those populations to evaluate their taxonomic affinity. Karyotypic data indicated that individuals from western Michoacán (Dos Aguas and Aguililla) and from a newly discovered population in northeastern Michoacán (Zinapécuaro) were chromosomally similar to P. carletoni (FN = 68) but distinct from other taxa assigned to the P. boylii species group. Analyses of cranial characteristics indicated that, relative to other species in the P. boylii species group, two morphologically distinct groups were present that corresponded to the Dos Aguas/Aguililla and Zinapécuaro populations, respectively. The latter population, although represented by a small sample size (n = 5 specimens), appeared to exhibit some trenchant morphological distinctions compared with other cryptic species in the P. boylii group. Phylogenetic analyses (parsimony, Bayesian, and likelihood) of DNA sequences obtained from the mitochondrial cytochrome-b gene indicated that although the individuals from Dos Aguas/Aguililla and Zinapécuaro formed a sister group relationship, they formed monophyletic clades that differed genetically (2.54%)-a level approaching that seen between other sister species of Peromyscus. Further, the Dos Aguas/Aguililla and Zinapécuaro clade was more closely aligned with a clade containing representatives of P. carletoni and P. levipes instead of with those from closer geographic proximities (P. kilpatricki) located in eastern Michoacán. Together, these results indicated that these two populations seemingly represent two undescribed species in the P. boylii species group for which we propose the names Peromyscus greenbaumi for populations in western Michoacán (circa Dos Aguas and Aguililla) and Peromyscus ensinki for populations in northeastern Michoacán (circa Zinapécuaro).


Los especímenes del grupo de especies de Peromyscus boylii distribuidos en las regiones montañosas occidentales y el noreste de Michoacán, México, históricamente fueron asignados a P. levipes. Sin embargo, estudios previos han indicado que estos especímenes poseen haplotipos de ADN mitocondrial que son distintos de P. levipes y P. kilpatricki, una especie recientemente nombrada en el grupo de especies P. boylii del noreste de Michoacán y el oeste de Morelos. Los datos cariotípicos indicaron que los individuos del oeste de Michoacán (Dos Aguas y Aguililla) y de una población recién descubierta en el noreste de Michoacán (Zinapécuaro) eran cromosómicamente similares a P. carletoni (FN = 68), pero distintos de otros taxones asignados al grupo de especies P. boylii. Los análisis de las características craneales indicaron que en relación con otras especies del grupo de especies P. boylii, dos grupos morfológicamente distintos estaban presentes, y que correspondían a las poblaciones de Dos Aguas/Aguililla y Zinapécuaro, respectivamente. Aunque representada por un tamaño de muestra pequeño (n = 5 especímenes), esta última población pareció exhibir algunas diferencias morfológicas en comparación con las otras especies crípticas en el grupo P. boylii. Los análisis filogenéticos (parsimonia, inferencia bayesiana y verosimilitud) de secuencias de ADN obtenidas del gen mitocondrial citocromo-b, indicaron que, aunque los individuos de Dos Aguas/Aguililla y Zinapécuaro tienen una relación de grupo hermano, estos forman clados monofiléticos que difieren genéticamente (2.54%), nivel que se acerca al observado entre otras especies hermanas de Peromyscus. Además, el clado de Dos Aguas/Aguililla y Zinapécuaro está más estrechamente alineado con un clado que contenía representantes de P. carletoni y P. levipes en lugar de aquellos de proximidades geográficas más cercanas (P. kilpatricki) ubicados en el este de Michoacán. Estos resultados indicaron que estas dos poblaciones aparentemente representan dos especies no descritas en el grupo de especies P. boylii para las cuales proponemos los nombres Peromyscus greenbaumi para poblaciones en el oeste de Michoacán (hacia Dos Aguas y Aguililla) y Peromyscus ensinki para poblaciones en el noreste de Michoacán (circa Zinapécuaro).

9.
PLoS One ; 16(10): e0255555, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34613994

RESUMEN

The jaguar (Panthera onca) is one of the most threatened carnivores in the Americas. Despite a long history of research on this charismatic species, to date there have been few systematic efforts to assess its population size and status in most countries across its distribution range. We present here the results of the two National Jaguar Surveys for Mexico, the first national censuses in any country within the species distribution. We estimated jaguar densities from field data collected at 13 localities in 2008-2010 (2010 hereafter) and 11 localities in 2016-2018 (2018 hereafter). We used the 2010 census results as the basis to develop a National Jaguar Conservation Strategy that identified critical issues for jaguar conservation in Mexico. We worked with the Mexican government to implement the conservation strategy and then evaluated its effectivity. To compare the 2010 and 2018 results, we estimated the amount of jaguar-suitable habitat in the entire country based on an ecological niche model for both periods. Suitable jaguar habitat covered ~267,063 km2 (13.9% of the country's territory) in 2010 and ~ 288,890 km2 (~14.8% of the country's territory) in 2018. Using the most conservative density values for each priority region, we estimated jaguar densities for both the high and low suitable habitats. The total jaguar population was estimated in ~4,000 individuals for 2010 census and ~4,800 for the 2018 census. The Yucatan Peninsula was the region with the largest population, around 2000 jaguars, in both censuses. Our promising results indicate that the actions we proposed in the National Jaguar Conservation Strategy, some of which have been implemented working together with the Federal Government, other NGO's, and land owners, are improving jaguar conservation in Mexico. The continuation of surveys and monitoring programs of the jaguar populations in Mexico will provide accurate information to design and implement effective, science-based conservation measures to try to ensure that robust jaguar populations remain a permanent fixture of Mexico's natural heritage.


Asunto(s)
Conservación de los Recursos Naturales/legislación & jurisprudencia , Panthera/fisiología , Política Pública/legislación & jurisprudencia , Animales , Ecosistema , México , Densidad de Población
10.
Proc Natl Acad Sci U S A ; 118(37)2021 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-34462334

RESUMEN

Globally, human-caused environmental impacts, such as habitat loss, have seriously impacted raptor species, with some 50% of species having decreasing populations. We analyzed global patterns of distribution of all 557 raptor species, focusing on richness, endemism, geographic range, conservation status, and population trends. Highest species diversity, endemism, species at risk, or restricted species were concentrated in different regions. Patterns of species distribution greatly differed between nocturnal and diurnal species. To test the efficiency of the global protected areas in conserving raptors, we simulated and compared global reserve systems created with strategies aiming at: 1) constraining the existing system into the final solution; and 2) minimizing the socioeconomic cost of reserve selection. We analyzed three targets of species distribution to be protected (10, 20, 30%). The first strategy was more efficient in meeting targets and less efficient in cost and compactness of reserves. Focusing on actions in the existing protected areas is fundamental to consolidate conservation, and politically and economically more viable than creating new reserves. However, creating new reserves is essential to protect more populations throughout the species' geographic range. Our findings provide a fundamental understanding of reserves to maintain raptor diversity and reduce the global population and species extinction crisis.


Asunto(s)
Biodiversidad , Conservación de los Recursos Naturales , Ecosistema , Monitoreo del Ambiente , Extinción Biológica , Densidad de Población , Animales , Sistemas de Información Geográfica , Rapaces
11.
Int J Mol Sci ; 22(16)2021 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-34445459

RESUMEN

An understanding of the immune mechanisms that lead to rejection versus tolerance of allogeneic pancreatic islet grafts is of paramount importance, as it facilitates the development of innovative methods to improve the transplant outcome. Here, we used our established intraocular islet transplant model to gain novel insight into changes in the local metabolome and proteome within the islet allograft's immediate microenvironment in association with immune-mediated rejection or tolerance. We performed integrated metabolomics and proteomics analyses in aqueous humor samples representative of the graft's microenvironment under each transplant outcome. The results showed that several free amino acids, small primary amines, and soluble proteins related to the Warburg effect were upregulated or downregulated in association with either outcome. In general, the observed shifts in the local metabolite and protein profiles in association with rejection were consistent with established pro-inflammatory metabolic pathways and those observed in association with tolerance were immune regulatory. Taken together, the current findings further support the potential of metabolic reprogramming of immune cells towards immune regulation through targeted pharmacological and dietary interventions against specific metabolic pathways that promote the Warburg effect to prevent the rejection of transplanted islets and promote their immune tolerance.


Asunto(s)
Rechazo de Injerto/metabolismo , Células Secretoras de Insulina/metabolismo , Trasplante de Islotes Pancreáticos , Metabolómica , Proteómica , Tolerancia al Trasplante , Aloinjertos , Animales , Rechazo de Injerto/patología , Células Secretoras de Insulina/patología , Masculino , Ratones
12.
PLoS One ; 15(11): e0241925, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33152016

RESUMEN

The application of artificial intelligence (AI) and machine learning (ML) in biomedical research promises to unlock new information from the vast amounts of data being generated through the delivery of healthcare and the expanding high-throughput research applications. Such information can aid medical diagnoses and reveal various unique patterns of biochemical and immune features that can serve as early disease biomarkers. In this report, we demonstrate the feasibility of using an AI/ML approach in a relatively small dataset to discriminate among three categories of samples obtained from mice that either rejected or tolerated their pancreatic islet allografts following transplant in the anterior chamber of the eye, and from naïve controls. We created a locked software based on a support vector machine (SVM) technique for pattern recognition in electropherograms (EPGs) generated by micellar electrokinetic chromatography and laser induced fluorescence detection (MEKC-LIFD). Predictions were made based only on the aligned EPGs obtained in microliter-size aqueous humor samples representative of the immediate local microenvironment of the islet allografts. The analysis identified discriminative peaks in the EPGs of the three sample categories. Our classifier software was tested with targeted and untargeted peaks. Working with the patterns of untargeted peaks (i.e., based on the whole pattern of EPGs), it was able to achieve a 21 out of 22 positive classification score with a corresponding 95.45% prediction accuracy among the three sample categories, and 100% accuracy between the rejecting and tolerant recipients. These findings demonstrate the feasibility of AI/ML approaches to classify small numbers of samples and they warrant further studies to identify the analytes/biochemicals corresponding to discriminative features as potential biomarkers of islet allograft immune rejection and tolerance.


Asunto(s)
Predicción/métodos , Rechazo de Injerto/fisiopatología , Trasplante de Islotes Pancreáticos/métodos , Animales , Inteligencia Artificial , Diabetes Mellitus Experimental/inmunología , Femenino , Supervivencia de Injerto/inmunología , Tolerancia Inmunológica , Terapia de Inmunosupresión/métodos , Islotes Pancreáticos/inmunología , Islotes Pancreáticos/metabolismo , Isoantígenos/inmunología , Aprendizaje Automático , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos DBA , Máquina de Vectores de Soporte , Trasplante Homólogo
13.
Sensors (Basel) ; 20(18)2020 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-32957655

RESUMEN

Using multimodal signals to solve the problem of emotion recognition is one of the emerging trends in affective computing. Several studies have utilized state of the art deep learning methods and combined physiological signals, such as the electrocardiogram (EEG), electroencephalogram (ECG), skin temperature, along with facial expressions, voice, posture to name a few, in order to classify emotions. Spiking neural networks (SNNs) represent the third generation of neural networks and employ biologically plausible models of neurons. SNNs have been shown to handle Spatio-temporal data, which is essentially the nature of the data encountered in emotion recognition problem, in an efficient manner. In this work, for the first time, we propose the application of SNNs in order to solve the emotion recognition problem with the multimodal dataset. Specifically, we use the NeuCube framework, which employs an evolving SNN architecture to classify emotional valence and evaluate the performance of our approach on the MAHNOB-HCI dataset. The multimodal data used in our work consists of facial expressions along with physiological signals such as ECG, skin temperature, skin conductance, respiration signal, mouth length, and pupil size. We perform classification under the Leave-One-Subject-Out (LOSO) cross-validation mode. Our results show that the proposed approach achieves an accuracy of 73.15% for classifying binary valence when applying feature-level fusion, which is comparable to other deep learning methods. We achieve this accuracy even without using EEG, which other deep learning methods have relied on to achieve this level of accuracy. In conclusion, we have demonstrated that the SNN can be successfully used for solving the emotion recognition problem with multimodal data and also provide directions for future research utilizing SNN for Affective computing. In addition to the good accuracy, the SNN recognition system is requires incrementally trainable on new data in an adaptive way. It only one pass training, which makes it suitable for practical and on-line applications. These features are not manifested in other methods for this problem.


Asunto(s)
Aprendizaje Profundo , Emociones , Encéfalo/diagnóstico por imagen , Electroencefalografía , Humanos , Redes Neurales de la Computación
14.
Proc Natl Acad Sci U S A ; 117(24): 13596-13602, 2020 06 16.
Artículo en Inglés | MEDLINE | ID: mdl-32482862

RESUMEN

The ongoing sixth mass species extinction is the result of the destruction of component populations leading to eventual extirpation of entire species. Populations and species extinctions have severe implications for society through the degradation of ecosystem services. Here we assess the extinction crisis from a different perspective. We examine 29,400 species of terrestrial vertebrates, and determine which are on the brink of extinction because they have fewer than 1,000 individuals. There are 515 species on the brink (1.7% of the evaluated vertebrates). Around 94% of the populations of 77 mammal and bird species on the brink have been lost in the last century. Assuming all species on the brink have similar trends, more than 237,000 populations of those species have vanished since 1900. We conclude the human-caused sixth mass extinction is likely accelerating for several reasons. First, many of the species that have been driven to the brink will likely become extinct soon. Second, the distribution of those species highly coincides with hundreds of other endangered species, surviving in regions with high human impacts, suggesting ongoing regional biodiversity collapses. Third, close ecological interactions of species on the brink tend to move other species toward annihilation when they disappear-extinction breeds extinctions. Finally, human pressures on the biosphere are growing rapidly, and a recent example is the current coronavirus disease 2019 (Covid-19) pandemic, linked to wildlife trade. Our results reemphasize the extreme urgency of taking much-expanded worldwide actions to save wild species and humanity's crucial life-support systems from this existential threat.


Asunto(s)
Infecciones por Coronavirus/epidemiología , Ecosistema , Extinción Biológica , Neumonía Viral/epidemiología , Vertebrados , Animales , Animales Salvajes , COVID-19 , Cambio Climático , Comercio , Conservación de los Recursos Naturales , Especies en Peligro de Extinción , Actividades Humanas , Pandemias , Densidad de Población , Vertebrados/clasificación
17.
Zootaxa ; 4377(1): 51-73, 2018 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-29690055

RESUMEN

The northernmost Peruvian Andes, a unique biogeographic region characterized by the confluence of multiple distinct ecosystems (i.e. Amazon basin, Pacific rainforest, the Sechura Desert, the northern and central Andes), is the southernmost geographic range limit of the South American shrews representing the genus Cryptotis. In the northernmost Peruvian Andes, two poorly known species have traditionally been reported (C. peruviensis and C. equatoris). Our study, based on molecular and morphologic traits, confirms the presence of C. peruviensis but also the occurrence of C. montivaga, based on specimens erroneously assigned to C. equatoris. Moreover, a new species of Cryptotis from the páramo and montane forests of the Tabaconas Namballe National Sanctuary near the Ecuadorian border is also described. It is a member of the thomasi group and is distinguished from other South American shrews by a unique set of morphological characters, including large body size, comparatively short tail, simple ectoloph of M3, and large PM4 post protocrista.


Asunto(s)
Musarañas , Animales , Ecosistema , Bosques , Perú
18.
PLoS One ; 12(12): e0189104, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29228017

RESUMEN

Understanding the effects of global climate disruption on biodiversity is important to future conservation efforts. While taxonomic diversity is widely studied, functional diversity of plants, and recently animals, is receiving increasing attention. Most studies of mammals are short-term, focus on temperate habitats, and rely on traits described in the literature rather than generating traits from observations. Unlike previous studies, this long-term field study assessed the factors driving the functional and taxonomic diversity of small-mammal assemblages in dry tropical forests using both traits recorded from literature and a demographic database. We assessed the drivers (abundance and biomass, temperature and rainfall) of taxonomic richness and functional diversity for two rain-driven seasons in two adjacent but distinct forests-upland and lowland (arroyo or riparian) forests. Our analysis found that rainfall, both seasonal and atypical, was the primary factor driving functional and taxonomic diversity of small-mammal assemblages. Functional responses differed between the two types of forests, however, with effects being stronger in the harsher conditions of the upland forests than in the less severe conditions prevailing in the arroyo (riparian) forest. The latter also supports a richer, more diverse, and more stable small-mammal assemblage. These findings highlight the importance of climate to tropical biological diversity, as extreme climate events (hurricanes, droughts and floods) and disruption of rainfall patterns were shown to decrease biodiversity. They also support the need to preserve these habitats, as their high taxonomic diversity and functional redundancy makes them resilient against global climate disruption and local extreme events. Tropical dry forests constitute a potential reservoir for biodiversity and the ecosystem services they provide. Unfortunately, these forests are among the most endangered terrestrial ecosystems because of deforestation and the likely impacts of global climate disruption.


Asunto(s)
Cambio Climático , Mamíferos/clasificación , Animales , Bosques , México , Especificidad de la Especie
19.
PLoS One ; 12(11): e0186934, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29145486

RESUMEN

Identifying which species are at greatest risk, what makes them vulnerable, and where they are distributed are central goals for conservation science. While knowledge of which factors influence extinction risk is increasingly available for some taxonomic groups, a deeper understanding of extinction correlates and the geography of risk remains lacking. Here, we develop a predictive random forest model using both geospatial and mammalian species' trait data to uncover the statistical and geographic distributions of extinction correlates. We also explore how this geography of risk may change under a rapidly warming climate. We found distinctive macroecological relationships between species-level risk and extinction correlates, including the intrinsic biological traits of geographic range size, body size and taxonomy, and extrinsic geographic settings such as seasonality, habitat type, land use and human population density. Each extinction correlate exhibited ranges of values that were especially associated with risk, and the importance of different risk factors was not geographically uniform across the globe. We also found that about 10% of mammals not currently recognized as at-risk have biological traits and occur in environments that predispose them towards extinction. Southeast Asia had the most actually and potentially threatened species, underscoring the urgent need for conservation in this region. Additionally, nearly 40% of currently threatened species were predicted to experience rapid climate change at 0.5 km/year or more. Biological and environmental correlates of mammalian extinction risk exhibit distinct statistical and geographic distributions. These results provide insight into species-level patterns and processes underlying geographic variation in extinction risk. They also offer guidance for future conservation research focused on specific geographic regions, or evaluating the degree to which species-level patterns mirror spatial variation in the pressures faced by populations within the ranges of individual species. The added impacts from climate change may increase the susceptibility of at-risk species to extinction and expand the regions where mammals are most vulnerable globally.


Asunto(s)
Extinción Biológica , Geografía , Mamíferos , Animales , Cambio Climático
20.
Sci Adv ; 3(10): e1603080, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-29075662

RESUMEN

Global biodiversity loss is disproportionately rapid on islands, where invasive species are a major driver of extinctions. To inform conservation planning aimed at preventing extinctions, we identify the distribution and biogeographic patterns of highly threatened terrestrial vertebrates (classified by the International Union for Conservation of Nature) and invasive vertebrates on ~465,000 islands worldwide by conducting a comprehensive literature review and interviews with more than 500 experts. We found that 1189 highly threatened vertebrate species (319 amphibians, 282 reptiles, 296 birds, and 292 mammals) breed on 1288 islands. These taxa represent only 5% of Earth's terrestrial vertebrates and 41% of all highly threatened terrestrial vertebrates, which occur in <1% of islands worldwide. Information about invasive vertebrates was available for 1030 islands (80% of islands with highly threatened vertebrates). Invasive vertebrates were absent from 24% of these islands, where biosecurity to prevent invasions is a critical management tool. On the 76% of islands where invasive vertebrates were present, management could benefit 39% of Earth's highly threatened vertebrates. Invasive mammals occurred in 97% of these islands, with Rattus sp. as the most common invasive vertebrate (78%; 609 islands). Our results provide an important baseline for identifying islands for invasive species eradication and other island conservation actions that reduce biodiversity loss.


Asunto(s)
Especies en Peligro de Extinción , Especies Introducidas , Vertebrados , Animales , Biodiversidad , Cruzamiento , Conservación de los Recursos Naturales , Ecosistema , Extinción Biológica , Geografía , Humanos , Islas , Vertebrados/clasificación
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