ABSTRACT
Resumen Introducción: La Rata de Magdalena, Xenomys nelsoni, es un roedor endémico de México, de distribución restringida a las selvas bajas caducifolias densas, en una pequeña región de la costa del Pacífico mexicano. Es una especie poco conocida, catalogada como "En Peligro" de acuerdo con la Unión Internacional para la Conservación de la Naturaleza (IUCN). Este desconocimiento unido a la alta tasa de deforestación de su hábitat hace que su conservación sea prioritaria. Objetivo: Realizar un recuento histórico de los registros depositados en las colecciones científicas, generar mapas de distribución potencial y analizar el estado de conservación de la especie. Método: Los datos de ocurrencia de las especies se obtuvieron de la literatura y bases de datos digitales y se analizaron por décadas. Se utilizaron los programas GARP y MaxEnt para generar los modelos de nicho ecológico. La importancia de las variables en el modelo se estimó mediante un análisis Jackknife. Resultados: A lo largo de 129 años 19 recolectores registraron 69 ejemplares, de los cuales 65 están depositados en siete colecciones internacionales y una nacional. Aunque la especie sólo se ha recolectado en Jalisco y Colima, la distribución potencial de X. nelsoni incluye también el estado de Michoacán. De esta área estimada, sólo el 1.5 % se encuentra dentro de un Área Natural Protegida. Conclusiones: Los resultados de la distribución potencial podrían ser utilizados para verificar la presencia de la especie en lugares donde no ha sido recolectada como el norte de la Reserva de la Biosfera Chamela-Cuixmala y en algunas zonas de la provincia fisiográfica Costas del Sur en el estado de Michoacán. Es necesario incrementar los muestreos en regiones poco estudiadas predichas por el modelo y aumentar el área de protección.
Abstract Introduction: The Magdalena Rat, Xenomys nelsoni, is a rodent endemic to Mexico, whose distribution is restricted to dense tropical dry forests in a small region on the Pacific coast of Mexico. It is a poorly known species categorized as "Endangered" by the International Union for Conservation of Nature (IUCN). This lack of knowledge and the high rates of deforestation of its habitat makes its conservation a priority. Objective: To summarize the historical records deposited in scientific collections, to create potential distribution maps, and to analyze the conservation status of the species. Methods: We obtained species occurrence data from literature and digital databases, analyzing them by the decade. We used GARP and MaxEnt software to generate the ecological niche models. The importance of the variables in the model was estimated using the Jackknife technique. Results: Over 129 years, 19 collectors registered 69 specimens, of which 65 are deposited in one national and seven international collections. Although the species has only been collected in Jalisco and Colima, the potential distribution for X. nelsoni also includes the state of Michoacán. Of this estimated area, only 1.5 % is in a Protected Natural Area. Conclusions: The results of the potential distribution could be used to verify the presence of the species in places where it has not been collected, such as the northern part of the Chamela-Cuixmala Biosphere Reserve and in some areas of the physiographic province Costas del Sur in the state of Michoacán. It is needed to increase samplings in the least studied regions predicted by the model and expand the area of protection.
Subject(s)
Animals , Rats , Rats/anatomy & histology , Ecosystem , Endangered Species , MexicoABSTRACT
RESUMEN En Ecuador las especies exóticas invasoras (EEI) provocan consecuencias negativas en los aspectos ecológicos, económicos y de seguridad alimentaria. Los agroecosistemas hacen parte de los sectores productivos a nivel mundial, pero son vulnerables a sufrir invasiones biológicas por la constante actividad humana y por el traslado de vegetación, tierra y semillas, por lo que deben ser constantemente monitoreados, pues desempeñan un papel importante en la economía al ser fuente de empleo. El objetivo de esta investigación fue evaluar la influencia potencial de las EEI sobre los agroecosistemas de Ecuador continental a través del modelado del nicho ecológico. Se usó como método de modelación el algoritmo de máxima entropía y se emplearon los registros de presencia de seis especies de plantas, tres insectos y un molusco en sus regiones nativas y en zonas invadidas a nivel mundial. Los registros provienen de Global Biodiversity Information Facility y de Tropicos. Como variables explicativas se emplearon 19 variables bioclimáticas y seis variables de vegetación. Se obtuvieron los mapas de distribución geográfica potencial, las áreas de superposición de la distribución de las especies y la delimitación de las zonas de mayor riesgo. Se determinó que las condiciones ambientales de las regiones Sierra y Amazónica son idóneas para una posible invasión de seis y siete especies. Además, más del 50 % de la cobertura agropecuaria del país podría ser afectada por las especies Wasmannia rochai, Spondias purpurea L., Lissachatina fúlica y Conium maculatum L., siendo los cultivos de ciclo corto los más vulnerables a la invasión por estas especies.
ABSTRACT In Ecuador, invasive alien species (IAS) cause negative consequences in ecology, economy, and food security. Agroecosystems belong to one of the productive sectors worldwide but are vulnerable to biological invasions by constant human activity and the transfer of vegetation, soil, and seeds, so they must be constantly monitored because of their important role in the economy to be a source of employment. The objective of this research was to evaluate the potential influence of IAS on the agroecosystems of continental Ecuador through the modeling of the ecological niche. The maximum entropy algorithm was used as a modeling method, and the presence register in the native region and invaded areas at a global level of six plant species, three insect species and one mollusc species were used. Data were obtained from the Global Biodiversity Information Facility and Tropicos. As explanatory variables, 19 bioclimatic variables, and six vegetation variables were used. Maps of potential geographical distribution, the overlap areas of the distribution of the species, and the delimitation of the zones of greater risk were obtained. It was determined that the environmental conditions of the Sierra and the Amazonian regions are ideal for a possible invasion of most species. Moreover, more than 50 % of the agricultural coverage of the country could be affected by Wasmannia rochai, Spondias purpurea L., Lissachatina fulica, and Conium maculatum L., with short cycle crops being the most vulnerable to invasion.
ABSTRACT
Activity, microhabitat use, and diet are patterns commonly used to define the saurian community structure, because of differential exploitation allowing coexistence at the same time and place. We analyze resource partitioning between two sympatric saurian species, Stenocercus puyango and Microlophus occipitalis, in the transitional area of the Pacific Tropical Forest and the Dry Forest inside Cerros de Amotape National Park (PNCA) in Tumbes, northwestern of Peru. Microlophus occipitalis and S. puyango both showed a unimodal activity pattern with higher activity around 13:00 h, with a mean body temperature of 34.83 °C and 32.17 °C respectively, observing a significant relationship between body and environmental (air and substrate) temperatures. Rocks and tree trunks were the most frequent microhabitats used by M. occipitalis while S. puyango were registered more frequently over leaf litter. The diets of both tropidurids were composed by arthropods, ants, and insect larvae mainly. Similarities in activity times (temporal niche) and diet (trophic niche) should be related to phylogenetic relationship and environmental characteristics of PNCA (seasonality, vegetal composition) meanwhile differences in space use and microhabitat thermal quality will be related to thermal quality in the area.
Los horarios de actividad, el uso de microhábitat y dieta, son patrones comúnmente utilizados para dilucidar la estructura de una comunidad de saurios, ya que estos hacen un uso diferenciado de los recursos que explotan, lo que les permite coexistir de forma adecuada en el mismo tiempo y lugar. Analizamos la repartición de recursos entre dos especies simpátridas de saurios, Stenocercus puyango y Microlophus occipitalis, en la zona transicional entre el Bosque Tropical del Pacifico y el Bosque Seco en el Parque Nacional Cerros de Amotape (PNCA), departamento de Tumbes, analizando el solapamiento del nicho espacial, temporal y trófico entre ambas especies, incluyendo algunos aspectos de sus ecologías termales. Microlophus occipitalis y S. puyango presentaron un patrón de actividad unimodal con un pico de actividad hacia las 13:00 horas y una temperatura corporal promedio de 34.83 °C y 32.17 °C, respectivamente, registrándose una relación significativa entre la temperatura corporal y las temperaturas ambientales (aire y suelo). Los microhábitats más utilizados por M. occipitalis fueron los troncos caídos y rocas, mientras que S. puyango fue registrado principalmente sobre hojarasca. La dieta de ambos tropidúridos estuvo compuesta por artrópodos, principalmente hormigas y larvas de insectos. Las similitudes encontradas tanto en los horarios de actividad (nicho temporal) como en la dieta (nicho trófico), estarían asociadas a su parentesco filogenético y a características ambientales propias dentro del PNCA (estacionalidad, composición vegetal), mientras que las diferencias en el uso del espacio y temperaturas corporales entre ambas especies estarían relacionada a la calidad térmica de los microhábitats presentes en el área.
ABSTRACT
Introducción: El proceso de invasión biológica es una de las mayores amenazas a la biodiversidad y ecosistemas, con actuales y potenciales impactos en la salud pública y conservación. Procambarus clarkii es un crustáceo decápodo, originario del sur de Estados Unidos y noreste de México, que puede adaptarse a diferentes condiciones ambientales debido a su plasticidad ecológica. Objetivo: Se caracterizó el nicho ecológico fundamental existente de Procambarus clarkii con el fin de predecir las áreas con idoneidad ambiental para el potencial establecimiento de la especie en Suramérica y Colombia. Métodos: Usamos modelos de nichos ecológicos calibrados en el área nativa, elaborados con el algoritmo Maxent, basados en datos de presencia extraídos de GBIF y variables hidroclimáticas de ecosistemas acuáticos a una resolución de 1 km2. Resultados: En Suramérica el modelo indicó un potencial geográfico amplio de invasión mostrando áreas ambientalmente idóneas para la presencia y expansión hacia Colombia, Venezuela, Perú, Ecuador, Brasil, Guyana, Surinam, Bolivia, Uruguay, Argentina, Paraguay y Chile. En Colombia, el modelo predijo que las áreas idóneas se ubican principalmente en el norte y oriente, incluidos diversos ecosistemas, como: bosques tropicales, bosques basales, bosques riparios y sabanas. La especie tiene una alta posibilidad de expandirse hacia áreas de distribución de latitudes bajas, ocupando zonas hacia la parte norte de la región Caribe colombiana, en departamentos de Magdalena, Cesar, Córdoba y Atlántico. También se predijo áreas con idoneidad ambiental en el oriente de Colombia, hacia la extensión de la planicie oriental de la Orinoquia, una región de baja altitud en: Arauca, Casanare, Meta y Vichada. Conclusión: En este estudio se aplican modelos de nichos ecológicos, que puede ser de interés en la planeación de estrategias o la creación de planes de manejo, como sistemas de alerta temprana para evitar el establecimiento de esta especie.
Introduction: Biological invasions are a major threat to biodiversity and ecosystems, with current and potential impacts on public health and conservation. Procambarus clarkii is a decapod crustacean, native to the Southern United States and Northeastern Mexico, which may adapt to different environmental conditions due to its ecological plasticity. Objective: The existing fundamental ecological niche of Procambarus clarkii was characterized in order to predict areas with environmental suitability for the potential establishment of the species in South America and Colombia. Methods: We used models of calibrated ecological niches in the native area, elaborated with the Maxent algorithm, based on occurrence data extracted from GBIF and hydroclimatic variables of aquatic ecosystems at a resolution of 1 km2. Results: The model indicated a wide geographic area for invasion potential in South America, predicting environmentally suitable areas for the presence and expansion towards Colombia, Venezuela, Peru, Ecuador, Brazil, Guyana, Surinam, Bolivia, Uruguay, Argentina, Paraguay and Chile. In Colombia, suitable areas predicted by the model are located mainly in the North and East of the country, spanning a diversity of ecosystems, such as tropical forests, basal forests, riparian forests and savannas. The species has a high possibility of expanding into low latitude distribution areas, occupying areas towards the Northern part of the Colombian Caribbean region, in the departments of Magdalena, Cesar, Cordoba and Atlántico. Suitability areas environmental were also predicted in Eastern Colombia, towards the extension of the Eastern plain of the Orinoquia, a low altitude region in Arauca, Casanare, Meta and Vichada. Conclusion: This study applies ecological niche models, which may be of interest in the planning of strategies or the creation of management plans, such as early warning systems that prevent the establishment of this species.
Subject(s)
Animals , Decapoda/growth & development , Colombia , Astacoidea/growth & development , Introduced Species/statistics & numerical dataABSTRACT
Abstract: Information on distribution, number of populations, and biotic interactions are essential for assessing the threat status of species and to establish more effective conservation initiatives. Ecological niche modeling have been successfully applied to identify the potential distribution, even for rare species that have few recorded occurrence points. In this study, we evaluated the potential distribution and additionally generated the first data on the reproductive biology of Discocactus ferricola, due to its degree of threat and the absence of ecological data for that species. The potential distribution map highlighted areas with higher probability of occurrence of D. ferricola on the Residual Plateau of Maciço do Urucum located in Mato Grosso do Sul, Brazil. The occurrence of D. ferricola populations was limited to outcrops of flat ironstone (cangas) distributed in patches across the landscape, increasing the chances of serious threats, such as habitat loss due to mining and species extraction. We also found that D. ferricola is xenogamous. Therefore, in situ conservation actions must prioritize the maintenance of interactions with pollinators by preserving the flora and fauna of rocky outcrops and adjacent forests in areas of greater environmental suitability for D. ferricola. Our study highlights the use of ecological niche modeling and data on biotic interactions to evaluate species potential distribution, to guide new sampling efforts, and to assist conservation and management initiatives.
Resumo: Informações sobre distribuição, número de populações e interações bióticas são essenciais para avaliar o status de ameaça das espécies e estabelecer iniciativas de conservação mais eficazes. A modelagem de nicho ecológico tem sido aplicada com sucesso para identificar a distribuição potencial, mesmo para espécies raras que possuem poucos pontos de ocorrência registrados. Neste estudo, avaliamos a distribuição potencial e adicionalmente geramos os primeiros dados sobre a biologia reprodutiva de Discocactus ferricola, devido ao seu grau de ameaça e à ausência de dados ecológicos para essa espécie. O mapa de distribuição potencial destacou áreas com maior probabilidade de ocorrência de D. ferricola no Planalto Residual do Maciço do Urucum localizado em Mato Grosso do Sul, Brasil. A ocorrência de populações de D. ferricola foi limitada aos afloramentos ferruginosos planos (cangas) que são distribuídos em manchas pela paisagem, aumentando as chances de ameaças graves, como perda de habitat devido à mineração e extração da espécie. Também descobrimos que D. ferricola é xenogâmica. Portanto, ações de conservação in situ devem priorizar a manutenção das interações com os polinizadores através da preservação da flora e da fauna nos afloramentos rochosos e florestas adjacentes nas áreas de maior adequabilidade ambiental para D. ferricola. Nesse estudo, nós destacamos o uso da modelagem de nicho ecológico e de dados sobre interações bióticas para avaliar a distribuição potencial de espécies, orientar novos esforços de amostragem e auxiliar iniciativas de conservação e manejo.
ABSTRACT
Resumen El objetivo es comprender la aparición y propagación de locuras puerperales en Argentina y Colombia, a finales del siglo XIX y principios del XX, así como su decadencia o desvanecimiento hacia la década de 1940-1950. Investigación histórico-hermenéutica, según los conceptos de "campo de visibilidad" y "nicho ecológico" de una enfermedad transitoria. No existió correlación entre embarazo, parto y puerperio con el estado delirante que motivaba la internación, atribuido a factores predisponentes y, asimismo, tuvieron una autonomía nosográfica en virtud de etiopatogenias singulares. Al tiempo que empezó a emerger el tipo clínico locura puerperal, se entrecruzaron el campo disciplinar de la obstetricia con el alienismo, con una mayor preponderancia del primero.
Abstract Our goal is to understand the appearance and spread of forms of puerperal insanity in Argentina and Colombia in the late nineteenth and early twentieth century, as well as their decline or disappearance around the 1940s. This is a historical and hermeneutical study, which uses the concepts of "field of visibility" and "ecological niche" for a transitory disease. There was no correlation between pregnancy, childbirth and puerperium and the state of delirium that led to commitment, which was attributed to predisposing factors; furthermore, forms of puerperal insanity were nosographically distinct due to their unique etiopathogeneses. As clinical cases of puerperal insanity started to emerge, the disciplinary field of obstetrics converged with psychiatry, with the former exerting more weight.
Subject(s)
Humans , Female , History, 19th Century , History, 20th Century , Puerperal Disorders/history , Puerperal Infection/history , Mental Disorders/history , Argentina , Puerperal Infection/psychology , Colombia , Parturition/psychologyABSTRACT
Abstract: Objective: To determine the species distribution, abundance, and diversity of culicids in the Yucatan Peninsula (YP); their potential distribution, using ecological niche modeling (ENM), and the risk of contact with urban and rural populations. Materials and methods: A cross-sectional study was carried out through the YP. The diversity of species was determined with the Shannon index. The potential distribution of the culicids was determined through the ENM, as well as the risk of urban and rural populations through contact with vectors. Results: A total of 10 699 specimens, 15 genera and 52 species were registered. Campeche and the Biosphere Reserve of Calakmul exhibited the highest diversity. Conclusions: The ENM predict a high suitability in all the YP of Ae. aegypti, An. albimanus, An. pseudopuntipennis, Cx. coronator, and Cx. quinquefasciatus. The vector species that exhibited the highest risk of contact in the YP were Cx. quinquefasciatus, Ae. aegypti and Ae. albopictus.
Resumen: Objetivo: Determinar la distribución, abundancia y di versidad de los culícidos de la Península de Yucatán (PY), su distribución potencial utilizando modelos de nicho ecológico (MNE) y el riesgo de contacto con poblaciones urbanas y rurales. Material y métodos: Se realizó un estudio transversal. La diversidad fue determinada por el índice de Shannon. La distribución potencial de los culícidos se deter minó a través de MNE, así como el riesgo de las poblaciones urbanas y rurales al contacto con los vectores. Resultados: En total, se registraron 10 699 especímenes, 15 géneros y 52 especies. Campeche y la Reserva de la Biosfera de Calakmul presentaron la mayor diversidad. Conclusiones: El MNE predice una alta idoneidad en toda la PY para Ae. aegypti, An. albimanus, An. pseudopuntipennis, Cx. coronador y Cx. quinque fasciatus. Las especies de vectores que presentaron el mayor riesgo de contacto en la PY fueron Cx. quinquefasciatus, Ae. aegypti y Ae. albopictus.
Subject(s)
Animals , Biodiversity , Mosquito Vectors , Culicidae , Cross-Sectional Studies , Population Density , Aedes , Culex , Insect Vectors , Anopheles , MexicoABSTRACT
El tomate (Solanum lycopersicum) es una de las principales hortalizas en el mundo debido a las importantes ganancias económicas que genera su comercialización; sin embargo, a pesar de que la especie es ampliamente cultivada en el mundo, su diversidad genética se considera restringida. Esto hace que su resistencia a plagas y enfermedades en las variedades actualmente cultivadas sea baja. Existe la forma silvestre S. l. var ceraciforme que se distribuye desde Suramérica (centro de origen) hasta México (área de domesticación), específicamente en la vertiente del Golfo de México en Veracruz. Como objetivo, se quiso identificar patrones de diversificación ambiental con los que se pudiesen inferir procesos de adaptación de las poblaciones en el área de domesticación con respecto a su centro de origen. Asimismo, se planteó proponer medidas de conservación y rescate del tomate S. l. var. cerasiforme. Se realizaron modelos de nicho ecológico (MNE) con Maxent versión 3.4.1 (evaluados con AUC y ROC-parcial) para determinar la idoneidad de las condiciones ambientales, incluyendo proyecciones del centro de domesticación al área de origen y viceversa. Esto se realizó con base en ocho variables de temperatura y precipitación. Los registros de tomate fueron tomados de fuentes bibliográficas y trabajo de campo. Seguidamente, se realizó la prueba de comparación de nichos (equivalencia y similitud), propuesta por Broennimann et al. (2012), para evaluar la similitud de condiciones ambientales en ambas regiones. Posteriormente, se realizó un análisis de varianza seguido de una prueba de comparación de medias (Tukey, P ≤ 0.05) con las ocho variables ambientales utilizadas. Los valores de AUC (0.93 y 0.80) y ROC-parcial obtenidos (1.86 y 1.71; P = 0.0001) de los MNE muestran que fueron buenos modelos predictores. Se observó que en el centro de México existen condiciones ambientales similares a las del centro de origen, a diferencia de la vertiente del Golfo de México donde son diferentes. La prueba de equivalencia mostró que la comparación ambiental entre ambas regiones es menos equivalente que lo esperado por azar (P = 0.003). Mientras tanto, la otra prueba indica que la similitud que existe entre ambas regiones también se puede obtener por azar (P = 0.683). También, se encontraron diferencias significativas en tres variables de temperatura y precipitación. En conclusión, el centro de origen y de domesticación de S. l. var. cerasiforme tienen características ambientales en común a pesar de la distancia geográfica, pero existen zonas geográficas (vertiente del Golfo de México en Veracruz) en el área de domesticación con condiciones ambientales diferentes a las de su centro de origen y con un potencial importante como bancos de germoplasma.
The tomato (Solanum lycopersicum) is one of the main horticultural crops in the world because of the important economic benefits that its commercialization generates. Even though the species is widely cultivated in the world, it is susceptible to pests, diseases, and environmental stresses due to the loss of its genetic diversity. There is a wild form called S. l. var ceraciforme that is distributed from South America (its center of origin) to Mexico (its area of domestication), specifically on the slope of the Gulf of Mexico in Veracruz. Due to the large genetic diversity of these wild tomatoes, it is important to improve its crop. The objective of this investigation was to identify patterns of environmental diversification of the tomato, infer the processes of adaptation of the populations in the area of domestication with respect to their center of origin and propose measures of conservation and variation of S. l. var. cerasiforme. We generated two ecological niche models (MNE) with Maxent version 3.4.1 (evaluated with AUC and partial-ROC) to determine the suitability of environmental conditions including their respective projections from the domestication center to the area of origin and vice versa. We used eight variables of temperature and precipitation. Additionally, we included tomato records from bibliographical sources and fieldwork. We also used the niche comparison test (equivalency and similarity) proposed by Broennimann et al. (2012) to evaluate the similarity of environmental conditions in both regions. Subsequently, we carried out an analysis of variance followed by a mean comparison test (Tukey, P ≤ 0.05) with all environmental variables measured. The values of AUC (0.93 and 0.80) and partial-ROC (1.86 and 1.71, P = 0.0001) of the MNE showed that they were good predictive models. We observed that, in the center of Mexico, there are environmental conditions similar to those of the center of origin, unlike the slope of the Gulf of Mexico where they are different. The equivalency test showed that the environmental comparison between both regions is less similar than expected by chance (P = 0.003). The similarity test indicated that the existing similarity between both regions can also be obtained by chance (P = 0.683). We also found significant differences in three temperature and precipitation variables. In conclusion, we determined that the center of origin and domestication of S. l. var. cerasiforme has similar environmental characteristics despite the geographic distance; nevertheless, there are geographical zones (the Gulf of Mexico in Veracruz) in the area of domestication with different environmental conditions. Those places have the potential to contain valuable germplasms.
ABSTRACT
Resumen Parachondria neglectus es un molusco terrestre de la familia Annulariidae, endémico de Cuba y microlocalizado en la provincia de Granma. En la presente investigación se caracterizaron la dinámica temporal del subnicho etario y algunos aspectos de la biología reproductiva de una población de P. neglectus localizada en Manzanillo, GranmaCuba. Se realizaron 30 expediciones entre diciembre 2013 y febrero 2015. Las comparaciones del largo (t = 8.05, P = 0.007) y diámetro mayor (t = 6.24, P = 0.0001) de las conchas de los juveniles truncados y los juveniles completos mostraron diferencias estadísticas significativas, indicando que ambos grupos representan dos clases de edades diferentes. La comparación del diámetro mayor de las conchas de los adultos truncados y los adultos completos (t = 1.50, P = 0.16) demostró que conforman un misma clase de edad en la población. La existencia de diferencias estadísticas significativas entre el largo (t = 19.45, P = 0.0003) y el diámetro mayor (t = 13.19, P = 0.006) de las conchas de las hembras y los machos reafirmaron el dimorfismo sexual en la especie, resultando las hembras de mayores dimensiones respecto a los machos. La mancha circular blancuzca en las conchas es una característica morfológica externa válida para diferenciar a las hembras adultas y ya apareadas en ocasiones anteriores, del resto de los miembros de la población. El período reproductivo comprendió de julio a diciembre 2014. Las cópulas se observaron de julio a octubre 2014 y estuvieron asociadas a condiciones de precipitaciones abundantes y temperaturas altas del verano. El período de reclutamiento ocurrió de septiembre a diciembre 2014.(AU)
Abstract Parachondria neglectus is a land snail of the Annulariidae family, endemic to Cuba and microlocalized in Granma province. In the present research, the temporal dynamics of age-related subniche and some aspects of the reproductive biology of a P. neglectus population, located in ManzanilloGranma-Cuba, were characterized. Thirty expeditions were performed from December 2013 to February 2015. The comparisons between the length (t = 8.05, P = 0.007) and biggest diameter (t = 6.24, P = 0.0001) of the shells of truncated juveniles and the shells of full juveniles showed significant statistical differences, indicating that both groups represent two kinds of different ages. The comparison between the biggest diameter of the shells of truncated adults and the shells of full adults (t = 1.50, P = 0.16) showed that both groups represent the same kind of age in the population. The existence of significant statistical differences between the length (t = 19.45, P = 0.0003) and the biggest diameter (t = 13.19, P = 0.006) of the females' shells and the males' shells verify the sexual dimorphism in the species, proving to be the females of bigger dimensions in relation to the males. The whitish circular spot in the shells is a valid external morphological characteristic to differentiate the adult females already mated in previous occasions from the rest of the members of the population. The reproductive period was from July to December 2014. Copulations were observed from July to October 2014 and they were associated to conditions of abundant precipitations and high temperatures of summer. The recruitment period took place from September to December 2014.(AU)
Subject(s)
Snails , Ecosystem , Reproduction , Cuba , Rainy SeasonABSTRACT
OBJECTIVE@#To investigate the effects of endothelial progenitor cells (EPCs) under shear stress on the biological function such as proliferation, adhesion, migration, apoptosis and expression of α-smooth muscle actin (α-SMA), collagen-I and collagen-Ⅲ of hepatic stellate cells (HSCs).@*METHODS@#HSCs and EPCs were inoculated into the upper and lower layers of the co-culture chamber respectively and co-incubated for 24 hours. Then, 12 dyne/cm shear stress was applied to EPCs cells for another 24 hours. After that, proliferation, adhesion, migration and apoptosis of HSCs were detected by cell counting kit-8 (CCK-8) kit, cell adherent assay, Boyden cell migration assay and flow cytometry respectively. Fluorescence quantitative PCR and Western blot were used to detect the mRNA and protein expression of alpha -SMA, collagen I and collagen-Ⅲ in HSCs.@*RESULTS@#Under shear stress, EPCs ecological niche could obviously inhibit the proliferation, adhesion and migration of HSCs, promote the apoptosis of HSCs, and down-regulate the mRNA and protein expression of collagen-I, collagen-Ⅲ in HSC cells.@*CONCLUSIONS@#Under shear stress, EPCs ecological niche could inhibit the fibrosis development of HSCs to a certain extent.
Subject(s)
Actins , Apoptosis , Cell Proliferation , Cells, Cultured , Collagen Type I , Endothelial Progenitor Cells , Hepatic Stellate CellsABSTRACT
Abstract Parrots are a seriously threatened group because of the illegal pet trade, their habitat fragmentation and the destruction of tropical forests. This study aimed to determine the relationship between forest fragmentation and the geographic potential distribution of parrot species in the Yucatan Peninsula, Mexico. The research was carried out in the Mexican portion of the Yucatan Peninsula Biotic region, which includes the states of Campeche, Quintana Roo and Yucatan. We worked with the eight species of psittacids that inhabit the selected areas: Eupsittula nana, Amazona albifrons, Amazona xantholora, Amazona autumnalis, Pionus senilis, Pyrilia haematotis, Amazona oratrix and Amazona farinosa. For these species, we used the potential geographical distribution maps that were obtained through the Maximum Entropy algorithm, published in 2014. To measure the levels of forest fragmentation in the Peninsula, we employed the land use and vegetation maps from series IV (2007-2010) of the National Institute of Statistics and Geography. We calculated different landscape metrics at 100 sites randomly distributed within the predicted presence and absence areas for the species. Multivariate methods were used to shorten dimensionality in the analysis, as well as to explore the observed patterns. We did not find any pattern regarding the number of variables that contribute to the logistic regression models (LR) and the size of the parrots' potential geographical distribution area within the Peninsula. For Pyrilia haematotis and Amazona oratrix, the fragmentation variables used did not seem to have any relationship with their potential geographical distribution in the Peninsula (intersection, Pr<0.0001). Only for Eupsittula nana, Amazona xantholora and Pionus senilis, we found that the mean patch edge, the mean shape index and the mean perimeterarea ratio were important to determine their potential distribution patterns, respectively; and, in general, the variables indicated the preferences of these parrots to occupy larger habitat patches. Parrots must be given a special care and protection within the states of Campeche and Quintana Roo, since there are areas with high parrot diversity and are importantly affected by human activities. The best recommendation for managers and users of protected areas within the Yucatan Peninsula is that extensive areas of forest should be maintained in order to guarantee the suvival of psittacid populations.
Resumen Los psitácidos se encuentran seriamente amenazados por el tráfico ilegal de mascotas y la destruc ción y fragmentación de su hábitat. El objetivo de este estudio fue determinar la relación entre la fragmentación y los patrones de distribución geográfica potencial de las especies de psitácidos de la Península de Yucatán, México. El estudio se realizó en la porción mexicana de la Provincia Biótica Península de Yucatán, que incluye los estados de Campeche, Quintana Roo y Yucatán. Se estudiaron las ocho especies de psitácidos que habitan la Península de Yucatán: Eupsittula nana, Amazona albifrons, Amazona xantholora, Amazona autumnalis, Pionus senilis, Pyrilia haematotis, Amazona oratrix y Amazona farinosa. Para las ocho especies se utilizaron los mapas de distribución geográfica potencial publicados en la literatura en el 2014, obtenidos con el algoritmo de máxima entropía (MaxEnt). Los mapas de uso de suelo y vegetación de la serie IV (2007-2010) del Instituto Nacional de Geografía y Estadística se usaron para medir los niveles de fragmentación de las selvas en la Península de Yucatán. Se calcularon diferentes métricas del paisaje en 100 parcelas distribuidas al azar dentro de las áreas de presencia y ausencia predichas para las especies. Se emplearon métodos multivariados para reducir dimensionalidad en los análisis, así como para explorar los patrones observados. No se encontró ningún patrón en cuanto al número de variables que aportan a los modelos de regresión logística (RL) y el tamaño del área de distribución geográfica potencial de los loros en la Península. Para Pyrilia haematotis y Amazona oratrix, la escala de trabajo con las variables de fragmentación, no parecen tener relación con su distribución geográfica potencial en la Península (intersección, Pr<0.0001). Solo para Eupsittula nana, Amazona xantholora y Pionus senilis secomprobó que la media del borde del fragmento, el índice medio de forma y la media de la proporción área-perímetro son importantes para determinar sus patrones de distribución respectivamente y en general apuntan una preferencia de estos loros por ocupar sitios que conservan fragmentos grandes de vegetación. Se le debe prestar mucha atención a la protección de los psitácidos en los estados de Campeche y Quintana Roo por ser áreas con una alta diversidad de loros y una zona altamente impactada por las actividades humanas. La recomendación más importante para los administradores y usuarios de las áreas protegidas dentro de la Península de Yucatán es que se deben mantener extensas áreas forestales para garantizar así la persistencia de las poblaciones de psitácidos.
ABSTRACT
Abstract Ecological niche modeling has contributed to the investigation of the geographical distribution and conservation of rare or little recorded species. Therefore, we studied the known and potential distributions of Colobosauroides carvalhoi Soares and Caramaschi 1998 and discuss the implications for its conservation. Data were obtained by manual collections made in quarterly samplings in three different regions, considering the regions with occurrence records and surrounding areas. The known distribution was determined by occurrence records and literature data, and potential distribution was estimated with an ecological niche model by the MaxEnt algorithm. Twenty-five specimens were collected exclusively in forest formations of Caatinga and Caatinga-Cerrado. Our data corroborated the relative rarity of C. carvalhoi and reflected the biogeographical history of the group, where it is restricted to forest formations with milder environmental conditions. The occurrence records indicated new records of C. carvalhoi, but the known distribution value is compatible with a restricted distribution. The ecological niche model estimated few areas with environmental suitability for the species and corroborated the restricted and relict distribution patterns. Finally, the known and potential distribution values were compatible with criteria for threatened species. These results suggest a worrisome scenario for C. carvalhoi conservation. However, the limited data about the species population do not allow the proper definition of its conservation status. Therefore, we suggest using potential distribution values with alternative criteria for redefining the conservation status of C. carvalhoi and the development of new studies that support a better assessment of its conservation aspects.
Resumo A modelagem ecológica de nicho vem contribuindo para investigar a distribuição geográfica e conservação de espécies raras ou com poucos registros de ocorrência. Neste sentido, investigou-se a distribuição conhecida e potencial da espécie Colobosauroides carvalhoi Soares & Caramaschi, 1998, discutindo as implicações para a conservação da espécie. Os dados foram coletados por meio de coletas manuais realizadas em amostragens trimestrais realizadas em três regiões distintas, considerando as regiões com registros de ocorrência conhecidos e áreas adjacentes. A distribuição conhecida foi determinada a partir dos novos registros de ocorrência e dados da literatura e a distribuição potencial estimada por meio de um modelo ecológico de nicho com uso do algoritmo MaxEnt. Vinte e cinco exemplares da espécie C. carvalhoi foram coletados exclusivamente em formações arbóreas da Caatinga e áreas de interface entre a Caatinga e o Cerrado. Estes resultados corroboram a relativa raridade da espécie e refletem a história biogeográfica do grupo, relacionada a ambientes florestados e que apresentam condições ambientais mais amenas. Os registros de ocorrência de C. carvalhoi indicam novos registros, entretanto, o valor de distribuição conhecida foi compatível com valores de distribuição restrita. O modelo ecológico de nicho estimou poucas áreas adequadas à ocorrência da espécie, corroborando um padrão de distribuição restrita e relictual. Por fim, os valores de distribuição conhecida e potencial estimados são compatíveis com valores definidos para espécies ameaçadas. Estes resultados sugerem um cenário preocupante para a conservação de C. carvalhoi. Entretanto, a atual limitação de dados populacionais dificulta uma adequada avaliação de seu status de conservação. Portanto, sugerimos o uso dos valores de distribuição potencial como critério alternativo para avaliar seu status de conservação até que novos estudos possam subsidiar uma melhor avaliação da conservação da espécie.
Subject(s)
Animals , Conservation of Natural Resources , Animal Distribution , Lizards , Brazil , Endangered Species , Models, BiologicalABSTRACT
Resumen: El loro corona lila (Amazona finschi), es una especie endémica de las tierras bajas de la costa del Pacífico mexicano y está considerada en peligro. Sin embargo, ha sido documentado que la especie presenta migraciones estacionales y altitudinales a lo largo de su rango geográfico, lo que sugiere que su distribución ecológica y temporal permanece incierta. Se modeló la distribución potencial del loro corona lila considerando sus dos principales periodos de actividad: reproductiva y no reproductiva. Para desarrollar modelos de nicho ecológico, se usaron 428 presencias históricas de bases de datos de libre acceso en internet, que fueron combinados con cinco coberturas ambientales: tres climáticas y dos topográficas para cada periodo, mediante el algoritmo de Maxent. Posteriormente transferimos cada modelo estacional al resto de los meses para analizar si los movimientos estacionales de la especie estaban dirigidos por el clima. Se evaluaron las diferencias en las variables ecológicas entre estaciones mediante el uso de una prueba de "t". Analizamos mediante la superposición de los mapas, la correspondencia geográfica entre la distribución de loro y la de los recursos (plantas), usados por la especie. Se encontró una marcada estacionalidad en la distribución del loro corona lila. La especie presenta una mayor amplitud ecológica en términos de temperatura mínima durante la temporada reproductiva, pero una notable reducción en lo que se refiere a la precipitación. La distribución de los recursos de anidación y alimentación corresponde en gran medida con la distribución del loro corona lila. En el centro del rango de distribución de la especie existe un área donde se presentan las condiciones de las que la especie hace uso en ambas temporadas y en los periodos de transición entre estas. Finalmente, además de las implicaciones en la conservación de la especie, nuestros resultados acerca de la variación estacional en la distribución geográfica y ecológica del loro corona lila, son importantes para la comprensión de la distribución de otras especies, particularmente aquellas que se encuentran asociadas con ambientes altamente estacionales.
Abstract: The lilac-crowned parrot (Amazona finschi) is an endemic species restricted to lowlands of the Mexican Pacific coast and is currently considered as endangered. It has been documented that it shows altitudinal and seasonal migrations along its distributional range, suggesting that its ecological and temporal distribution is still uncertain. We modeled the potential distribution of the A. finschi considering the two main activity seasons for the species: reproductive and non-reproductive. We used 428 historical occurrences (1882-2014), obtained from open access databases, combined with five environmental layers: three climatic and two topographic for each season, to perform ecological niche models using Maxent. We then transferred each model to the rest of the months to analyze the seasonal movements guided by climate. Differences in ecological variables between seasons were evaluated using a t-test. The geographic correspondence among the parrot distribution and the resources (plants) distributions were analyzed by superimposing maps. A marked seasonality in the distribution of A. finschi was observed. Ecologically, the species displays greater amplitude during the breeding seasons in terms of minimum temperature, but a noticeable reduction as far as precipitation is concerned. The distribution of food and nesting resources largely corresponds to the distribution of this parrot. There is a wide area in the center of the geographical distribution in which the species finds conditions that meet both periods of activity, as well as transition conditions between these periods. Finally, our results on the seasonal variation in the geographical and ecological distribution of this species, possess a strong ecological meaning in the understanding of other species distribution, particularly those associated with highly seasonal environments, and definitively will contribute to the conservation of this species. Rev. Biol. Trop. 65 (3): 1194-1207. Epub 2017 September 01.
ABSTRACT
ABSTRACT In the face of climate change threats, governments are drawing attention to policies for mitigating its effects on biodiversity. However, the lack of distribution data makes predictions at species level a difficult task, mainly in regions of higher biodiversity. To overcome this problem, we use native landcover as a surrogate biodiversity, because it can represent specialized habitat for species, and investigate the effects of future climate change on Brazilian biomes. We characterize the climatic niches of native landcover and use ecological niche modeling to predict the potential distribution under current and future climate scenarios. Our results highlight expansion of the distribution of open vegetation and the contraction of closed forests. Drier Brazilian biomes, like Caatinga and Cerrado, are predicted to expand their distributions, being the most resistant to climate change impacts. However, these would also be affected by losses of their closed forest enclaves and their habitat-specific or endemic species. Replacement by open vegetation and overall reductions are a considerable risk for closed forest, threatening Amazon and Atlantic forest biomes. Here, we evidence the impacts of climate change on Brazilian biomes, and draw attention to the necessity for management and attenuation plans to guarantee the future of Brazilian biodiversity.
ABSTRACT
BACKGROUND Oropouche virus causes Oropouche fever, an arboviral disease transmitted mainly by midges of the genus Culicoides and Culex mosquitoes. Clinical presentation of Oropouche fever in humans includes fever, headache, rash, myalgia, and in rare cases spontaneous bleeding and aseptic meningitis. Landscape change has been proposed as a driver of Oropouche fever emergence. OBJECTIVE To investigate the landscape epidemiology of the Oropouche fever outbreak that began in April 2016 in Cusco, Peru. METHODS We used information of vegetation and multivariate spatial analyses including ecological niche modeling. Vegetation was characterised using16-day composite enhanced vegetation index (EVI) images at 500 m spatial resolution from the MODIS sensor carried by the Terra satellite. FINDINGS Cases were distributed across seven Peruvian districts in two provinces. La Concepcion was the province with most of the affected districts. EVI time series across 2000 to 2016 suggested a decline in the vegetation in sites with Oropouche fever cases before the epidemic. Our ecological niche modeling suggests that other areas in Junin, Apurimac, and Madre de Dios departments are at risk of Oropouche fever occurrence. MAIN CONCLUSIONS Our results may provide a guide for future fieldwork to test hypotheses regarding Oropouche fever emergence and habitat loss in tropical Latin America.
Subject(s)
Humans , Arbovirus Infections/transmission , Arbovirus Infections/epidemiology , Disease Outbreaks , Ecosystem , Geographic Information Systems , Peru/epidemiology , Risk FactorsABSTRACT
ResumenLa leishmaniasis es un complejo sistema de enfermedades causadas por parásitos protozoarios Leishmania y transmitidos a humanos por el vector Lutzomyia spp, esta es considerada una enfermedad desatendida de acuerdo a la Organización Mundial de la salud. El objetivo de este estudio fue determinar el nicho ecológico actual y futuro de la leishmaniasis cutánea (LC) y leishmaniasis visceral (LV) en la región Neotropical. Nosotros construimos modelos de nicho ecológico (MNE) de LC (N= 2 910 ocurrencias) y LV (N= 851 ocurrencias) usando el algoritmo MaxEnt. Nueve variables bioclimáticas (BIO1, BIO4, BIO5, BIO6, BIO7, BIO12, BIO13, BIO14, BIO15; descargadas de Worldclim), y datos de ocurrencias fueron usados para la construcción de los MNE en tres periodos (actual, 2050 y 2070) y cuatro escenarios de cambio climático (RCP 2.6, 4.5, 6.0 y 8.5). Nosotros analizamos el número de pixeles ocupados, identidad de nicho, nicho modificado (estable, perdido y ganado) y estacionalidad. Nuestros resultados indican la expansión de la LC en comparación con la LV. Rechazamos la hipótesis nula de identidad de nicho entre LC y LV con un índice de Hellinger's = 0.91 (0.92-0.98) y Schoener's = 0.67 (0.85-1.00) pero con un traslape de nicho de 56.3 %. El tipo de leishmaniasis tiene diferentes coberturas de acuerdo al RCP y nicho modificado (ganado/ perdido). La LC tiene estacionalidad a diferencia de la LV. Los MNE de LC y LV proporcionar una visión actual de la región Neotropical, que presenta un mayor incremento de acuerdo con el tiempo, sin embargo, el aumento estacional modificaría la invasión de nuevas áreas en la región.
Abstract:The leishmaniasis is a complex disease system, caused by the protozoan parasite Leishmania and transmitted to humans by the vector Lutzomyia spp. Since it is listed as a neglected disease according to the World Health Organization, the aim of this study was to determine the current and future niche of cutaneous and visceral leishmaniasis in the Neotropical region. We built the ecological niche model (ENM) of cutaneous (N= 2 910 occurrences) and visceral (N= 851 occurrences) leishmaniasis using MaxEnt algorithm. Nine bioclimatic variables (BIO1, BIO4, BIO5, BIO6, BIO7, BIO12, BIO13, BIO14, BIO15 (downloaded from the Worldclim) and disease occurrences data were used for the construction of ENM for three periods (current, 2050 and 2070) and four climate change scenarios (RCP 2.6, 4.5, 6.0 y 8.5). We analyzed the number of pixels occupied, identity niche, modified niche (stable, loss, and gain) and seasonality. Our analyses indicated the expansion for cutaneous leishmaniasis (CL), a comparison for visceral leishmaniasis (VL). We rejected the null hypothesis of niche identity between CL and VL with Hellinger's index = 0.91 (0.92-0.98) and Schoener's Index = 0.67 (0.85-1.00) but with an overlap niche of 56.3 %. The differences between the two leishmaniasis types were detected in relation to RCP scenarios and niche shifts (area gained / loss). Seasonality was more important for CL. We provided a current picture of CL and VL distributions and the predicted distributional changes associated to different climate change scenarios for the Neotropical region. We can anticipate that increasing range is likely although it will depend locally on the future trends in weather seasonality. Rev. Biol. Trop. 64 (3): 1237-1245. Epub 2016 September 01.
Subject(s)
Humans , Animals , Tropical Climate , Leishmaniasis, Cutaneous/epidemiology , Ecosystem , Leishmaniasis, Visceral/epidemiology , Psychodidae , Seasons , Temperature , Climate Change , Risk Factors , Leishmaniasis, Cutaneous/transmission , Insect Vectors , Latin America/epidemiology , Leishmaniasis, Visceral/transmission , Models, BiologicalABSTRACT
ResumenLos especímenes silvestres de Vanilla planifolia G. Jack forman parte del acervo genético primario, los cuales solo se han reportado en Oaxaca, México. Por ello se evaluó la distribución de esta especie con el objetivo de ubicar y describir características ecológicas en zonas potenciales de distribución. La metodología empleada consistió de cuatro etapas: 1) Elaboración de una base de datos con registros de herbario;2) Construcción de la distribución potencial basado en los registros históricos de herbario para la especie, mediante el modelo de máxima entropía (Maxent), con el uso de 22 variables bioclimáticas como predictoras; 3) Realización de búsquedas sistemáticas de individuos in situ con base en los registros de herbario y las áreas de distribución potencial en 24 municipios, para conocer la situación y la distribución del hábitat actual, y 4) Descripción mediante factores ambientales de los nichos ecológicos potenciales generados por MaxEnt. La revisión de las colecciones de herbarios reportó un total de 18 registros de V. planifolia, comprendidos entre 1939 y 1998.La búsqueda sistemática de individuos en campo ubicó 28 plantas distribuidas en 12 sitios sobre 95 364 Km2. Las variables que contribuyeron con mayor valor porcentual para determinar la estimación del modelo de distribución potencial en vainilla son precipitación del periodo más lluvioso (61.9 %), régimen de humedad del suelo (23.4 %) y precipitación del cuatrimestre más lluvioso (8.1 %). El hábitat potencial de la especie se distribuyó en cuatro zonas; trópico húmedo del golfo de México, templado húmedo, trópico húmedo y templado húmedo del pacifico. La precipitación anual osciló de 2 500 a 4 000 mm, con lluvias en verano y porcentaje de precipitación invernal de 5 a 10 %. El régimen de humedad y clima predominantes fueron údico tipo I (330 a 365 días de humedad) y cálido húmedo (Am/A(C) m). Las plantas se ubicaron en altitudes de 200 a 1 190 msnm, en laderas accidentadas, que por lo general están al pie de sistemas montañosos de 1 300 a 2 500 metros de altitud. En condiciones naturales la distribución de la especie no se limita a selva alta perennifolia, dado que se ubicó en bosque mesófilo de montaña y bosque tropical perennifolio. La ubicación de nuevos especímenes de V. planifolia en condiciones silvestres reduce un 66 % del área potencial de distribución, y la fragmenta, al pasar de ser una zona continua a convertirse en tres zonas geográficamente separadas. La reducción del hábitat se debió a un aumento en el número de plantas ubicadas, lo que define las condiciones ambientales a un nivel más exacto. Por lo anterior, se pueden emprender o diseñar acciones de conservación enfocadas a áreas más específicas dentro del estado de Oaxaca, México.
AbstractWild specimens of Vanilla planifolia represent a vital part of this resource primary gene pool, and some plants have only been reported in Oaxaca, Mexico. For this reason, we studied its geographical distribution within the state, to locate and describe the ecological characteristics of the areas where they have been found, in order to identify potential areas of establishment. The method comprised four stages: 1) the creation of a database with herbarium records, 2) the construction of the potential distribution based on historical herbarium records for the species, using the model of maximum entropy (MaxEnt) and 22 bioclimatic variables as predictors; 3) an in situ systematic search of individuals, based on herbarium records and areas of potential distribution in 24 municipalities, to determine the habitat current situation and distribution; 4) the description of the environmental factors of potential ecological niches generated by MaxEnt. A review of herbarium collections revealed a total of 18 records of V. planifolia between 1939 and 1998. The systematic search located 28 plants distributed in 12 sites in 95 364 Km2. The most important variables that determined the model of vanilla potential distribution were: precipitation in the rainy season (61.9 %), soil moisture regime (23.4 %) and precipitation during the four months of highest rainfall (8.1 %). The species potential habitat was found to be distributed in four zones: wet tropics of the Gulf of Mexico, humid temperate, humid tropical, and humid temperate in the Pacific. Precipitation oscillated within the annual ranges of 2 500 to 4 000 mm, with summer rains, and winter precipitation as 5 to 10 % of the total. The moisture regime and predominating climate were udic type I (330 to 365 days of moisture) and hot humid (Am/A(C) m). The plants were located at altitudes of 200 to 1 190 masl, on rough hillsides that generally make up the foothills of mountain systems, with altitudes of 1 300 to 2 500 masl. In natural conditions, distribution of the species is not limited to high evergreen forests, since it was also found in mountain mesophyll and tropical evergreen forests. The location of new specimens of V. planifolia in its wild condition reduces the potential distribution area by 66 %. This area is fragmented into three geographically separated areas. Habitat reduction was due to the increased number of located plants that define the environmental conditions into a more accurate level. Conservation actions can thus be designed and implemented, focusing on more specific areas within the state of Oaxaca, Mexico.
Subject(s)
Vanilla/classification , Seasons , Biodiversity , Geography , MexicoABSTRACT
AbstractThe aim of this study was to evaluate the ecological niche models (ENMs) for three specialist trees (Anadenantheracolubrina, Aspidosperma pyrifolium and Myracrodruon urundeuva) in seasonally dry tropical forests (SDTFs) in Brazil, considering present and future pessimist scenarios (2080) of climate change. These three species exhibit typical deciduousness and are widely distributed by SDTF in South America, being important in studies of the historical and evolutionary processes experienced by this ecosystem. The modeling of the potential geographic distribution of species was done by the method of maximum entropy (Maxent).We verified a general expansion of suitable areas for occurrence of the three species in future (c.a., 18%), although there was reduction of areas with high environmental suitability in Caatinga region. Precipitation of wettest quarter and temperature seasonality were the predictor variables that most contributed to our models. Climatic changes can provide more severe and longer dry season with increasing temperature and tree mortality in tropics. On this scenario, areas currently occupied by rainforest and savannas could become more suitable for occurrence of the SDTF specialist trees, whereas regions occupied by Caatinga could not support the future level of unsustainable (e.g., aridity). Long-term multidisciplinary studies are necessary to make reliable predictions of the plant’s adaptation strategies and responses to climate changes in dry forest at community level. Based on the high deforestation rate, endemism and threat, public policies to minimize the effects of climate change on the biodiversity found within SDTFs must be undertaken rapidly.
ResumoEste estudo tem como objetivo avaliar a modelagem de nicho ecológico (ENMs) para três espécies especialistas (Anadenantheracolubrina, Aspidosperma pyrifolium e Myracrodruon urundeuva) de florestas tropicais secas (FTSs) no Brasil, considerando o cenário de mudanças climáticas: presente e futuro pessimistas (2080). Estas três espécies são decíduas e amplamente distribuídas pelas FTSs na América do Sul, sendo importante em estudos sobre os processos históricos e evolutivos experimentados por este ecossistema. A modelagem da distribuição geográfica potencial das espécies foi construída através do método de máxima entropia (Maxent). Foi observada uma expansão geral de áreas adequadas para a ocorrência das três espécies no futuro (cerca de 18%), embora tenha existido uma redução das áreas com alta adequabilidade ambiental na região da Caatinga. A precipitação do trimestre mais úmido e a sazonalidade da temperatura foram os fatores que mais contribuíram para os nossos modelos. As mudanças climáticas podem gerar períodos secos mais severos e longos, com aumento da temperatura e mortalidade de árvores em regiões tropicais. Neste cenário, as áreas atualmente ocupadas por florestas úmidas e savanas poderiam tornar-se mais adequadas para a ocorrência das árvores especialistas em FTSs, enquanto que as regiões ocupadas por Caatinga não poderiam suportar o nível futuro da não adequabilidade (por exemplo, aridez). Estudos multidisciplinares de longa duração são necessários para fazer previsões confiáveis de estratégias adaptativas das plantas e respostas às variações climáticas em FTS em nível de comunidade. Com base na elevada taxa de desmatamento, endemismo e ameaça, políticas públicas para minimizar os efeitos das mudanças climáticas sobre a biodiversidade encontradas dentro FTSs devem ser realizadas rapidamente.
Subject(s)
Climate Change , Ecosystem , Plant Dispersal , Trees/physiology , Anacardiaceae/physiology , Aspidosperma/physiology , Brazil , Forests , Fabaceae/physiology , Models, BiologicalABSTRACT
This study updates the geographic distributions of phlebotomine species in Central-West Brazil and analyses the climatic factors associated with their occurrence. The data were obtained from the entomology services of the state departments of health in Central-West Brazil, scientific collections and a literature review of articles from 1962-2014. Ecological niche models were produced for sandfly species with more than 20 occurrences using the Maxent algorithm and eight climate variables. In all, 2,803 phlebotomine records for 127 species were analysed. Nyssomyia whitmani, Evandromyia lenti and Lutzomyia longipalpis were the species with the greatest number of records and were present in all the biomes in Central-West Brazil. The models, which were produced for 34 species, indicated that the Cerrado areas in the central and western regions of Central-West Brazil were climatically more suitable to sandflies. The variables with the greatest influence on the models were the temperature in the coldest months and the temperature seasonality. The results show that phlebotomine species in Central-West Brazil have different geographical distribution patterns and that climate conditions in essentially the entire region favour the occurrence of at least one Leishmania vector species, highlighting the need to maintain or intensify vector control and surveillance strategies.
Subject(s)
Animals , Insect Vectors/classification , Phlebotomus/classification , Animal Distribution , Brazil , Climate , Leishmaniasis/transmission , Population Density , SeasonsABSTRACT
Chagas disease is one of the most important yet neglected parasitic diseases in Mexico and is transmitted by Triatominae. Nineteen of the 31 Mexican triatomine species have been consistently found to invade human houses and all have been found to be naturally infected with Trypanosoma cruzi. The present paper aims to produce a state-of-knowledge atlas of Mexican triatomines and analyse their geographic associations with T. cruzi, human demographics and landscape modification. Ecological niche models (ENMs) were constructed for the 19 species with more than 10 records in North America, as well as for T. cruzi. The 2010 Mexican national census and the 2007 National Forestry Inventory were used to analyse overlap patterns with ENMs. Niche breadth was greatest in species from the semiarid Nearctic Region, whereas species richness was associated with topographic heterogeneity in the Neotropical Region, particularly along the Pacific Coast. Three species, Triatoma longipennis, Triatoma mexicana and Triatoma barberi, overlapped with the greatest numbers of human communities, but these communities had the lowest rural/urban population ratios. Triatomine vectors have urbanised in most regions, demonstrating a high tolerance to human-modified habitats and broadened historical ranges, exposing more than 88% of the Mexican population and leaving few areas in Mexico without the potential for T. cruzi transmission.