scholarly journals Generación de modelos de distribución de ecosistemas vulnerables al cambio climático [Generation of distribution models of vulnerable ecosystems towards climate change]

Author(s):  
Elena Posada ◽  
Héctor Mauricio Ramírez Díaz ◽  
Paola Isaacs Cubides ◽  
Martha Paola Barajas Barbosa

Resumen Se presenta un avance de los resultados del proyecto “Uso de sensores remotos y tecnologías asociadas para estudio de ecosistemas forestales ante el cambio climático global”, realizadas en el marco de la red temática FORCLIM patrocinado por el Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo (Cyted). De dicha red temática hace parte el grupo de Percepción Remota y Aplicaciones Geográficas del Instituto Geográfico Agustín Codazzi, Oficina CIAF. En este contexto, como modelo metodológico se están trabajando datos de presencias del ecosistema páramo y bosque seco tropical, obtenidos de polígonos de cobertura de los ecosistemas continentales costeros y marinos del IDEAM –IGAC et al (2007). Se emplean datos de temperatura, precipitación y alturas descargados del proyecto WorldClim, los cuales se han procesado con ArcGIS y DIVA-GIS, para ser modelados junto con los datos de presencia en el programa MaxEnt. El resultado del modelo expresa el valor de idoneidad como una función de las variables ambientales. Para el trabajo se ha empleado un escenario futuro de incremento en la temperatura de tres y cinco grados Celsius, para determinar el comportamiento de dichas coberturas ante el calentamiento global. Se obtuvieron mapas de idoneidad actuales y futuros presentando una elevada tendencia a la disminución del páramo y aumento de los bosques secos, siendo la altura la variable que más contribuye para el páramo y la precipitación para bosque seco. Se presenta un proceso metodológico el cual sirve como insumo para modelar distribución de especies, en este caso incluyendo algunas variables empleadas para estudiar cambio climático y su integración con los datos obtenidos de sensores remotos. Palabras ClaveCambio climático, Distribución de especies, Red temática FORCLIM, Sensores remotos.   Abstract We present progress in the results of the research “Remote sensing use and associated technologies for ecosystem spatial changes evaluation concerning global climate change, in the frame of the thematic net FORCLIM, sponsored for the Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo (Cyted). The Remote Sensing and Geographic Applications Group of the Instituto Geográfico Agustín Codazzi–CIAF is member of the net. In this sense, as a method we are using paramo and tropical dry forest ecosystem presence data obtained from the geodatabase of the continental and marine ecosystems of IDEAM-IGAC et al (2007). We are using temperature, precipitation and elevation data from WorldClim Project, which were processed with DIVA-GIS software in order to be modeled among the presence data with MaxEnt program. The model result shows the suitable value as a function of the environmental variables. For this work we used two future scenarios, the first with 3°C and the second with 5°C increment. The suitable paramo current models and paramo future models showed a considerable decreasing, for the tropical dry forest the distribution raised. We present a methodology process, which is helpful as an species distribution modeling input; according to the climatic variables, and data recovered from remote sensing techniques (presence data).Keywords Climate change, Remote sensing, Species distributions, Thematic net FORCLIM.

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7866 ◽  
Author(s):  
José Guadalupe Martínez-Hernández ◽  
Angélica María Corona-López ◽  
Alejandro Flores-Palacios ◽  
Matthias Rös ◽  
Víctor Hugo Toledo-Hernández

Global climate change is expected to affect temperature and precipitation patterns worldwide, which in turn is likely to affect insect phenology, distribution and diversity. To improve our understanding of such processes, it is important to understand how insects may respond to changes in seasonality, and how these affect their activity, patterns of distribution and species richness. The tropical dry forest (TDF) is a highly seasonal ecosystem, for which two seasons are commonly described (rainy and dry) and there is a lack of information on the combined effect of both precipitation and temperature on the insect communities. In order to evaluate the seasonal patterns in the community of Cerambycidae in a TDF, historical climatic variables were obtained, and an annual sampling of the family was carried out, using three collection techniques. We found that the Cerambycidae family showed a more complex response to climate, than simply the rainy and dry season of the year. The relationship between diversity and composition of cerambycids with changes in temperature and precipitation showed four seasonal communities which were synchronized with phenological processes of the TDF. Climate change could reduce biodiversity, causing seasonal patterns to lose complexity, either because the climatic characteristics of a season disappear and/or because the duration of a season expands, these changes will modify the ecological processes of the TDF, since they would generate changes in the flora and fauna associated with the different seasons.


2021 ◽  
Vol 13 (19) ◽  
pp. 3845
Author(s):  
Guangbo Ren ◽  
Jianbu Wang ◽  
Yunfei Lu ◽  
Peiqiang Wu ◽  
Xiaoqing Lu ◽  
...  

Climate change has profoundly affected global ecological security. The most vulnerable region on Earth is the high-latitude Arctic. Identifying the changes in vegetation coverage and glaciers in high-latitude Arctic coastal regions is important for understanding the process and impact of global climate change. Ny-Ålesund, the northern-most human settlement, is typical of these coastal regions and was used as a study site. Vegetation and glacier changes over the past 35 years were studied using time series remote sensing data from Landsat 5/7/8 acquired in 1985, 1989, 2000, 2011, 2015 and 2019. Site survey data in 2019, a digital elevation model from 2009 and meteorological data observed from 1985 to 2019 were also used. The vegetation in the Ny-Ålesund coastal zone showed a trend of declining and then increasing, with a breaking point in 2000. However, the area of vegetation with coverage greater than 30% increased over the whole study period, and the wetland moss area also increased, which may be caused by the accelerated melting of glaciers. Human activities were responsible for the decline in vegetation cover around Ny-Ålesund owing to the construction of the town and airport. Even in areas with vegetation coverage of only 13%, there were at least five species of high-latitude plants. The melting rate of five major glaciers in the study area accelerated, and approximately 82% of the reduction in glacier area occurred after 2000. The elevation of the lowest boundary of the five glaciers increased by 50–70 m. The increase in precipitation and the average annual temperature after 2000 explains the changes in both vegetation coverage and glaciers in the study period.


2019 ◽  
Vol 10 (2) ◽  
pp. 490-505 ◽  
Author(s):  
Salvador Mandujano ◽  
Ariana Barrera-Salazar ◽  
Antonio Vergara-Castrejón

El manejo de caprinos (Capra hircus) en sistemas extensivos es una práctica común en la Reserva de la Biosfera Tehuacán-Cuicatlán (RBTC), México. En el presente estudio se analizó la similitud de las especies de plantas consumidas por los caprinos de diferentes rebaños en un paisaje de la Cañada en Oaxaca. Se siguió a ocho rebaños en diferentes localidades durante las épocas de lluvias 2012 y la de seca 2013. Para determinar la similitud espacial y temporal entre los rebaños dependiendo de las plantas consumidas, se emplearon métodos de análisis multivariado, específicamente de agrupamiento jerárquico en el programa R. Los caprinos consumieron 84 especies, de las cuales 30 constituyen el 75 % de la dieta. De acuerdo a los análisis de similitud, Mimosa sp. y Acacia cochiliacantha fueron las especies consumidas con mayor frecuencia por todos los rebaños; mientras que Eleusine indica, Prosopis leavigata y Opuntia sp. fueron las siguientes en importancia. El rebaño de la localidad Tecomovaca fue el menos similar al resto de los rebaños estudiados. Estos resultados contribuyen al entendimiento de los hábitos de forrajeo de los caprinos en región tropical seca, donde la disponibilidad de recursos es marcadamente estacional.


Author(s):  
Kayla D. Stan ◽  
Arturo Sanchez-Azofeifa ◽  
Sandra M. Duran ◽  
Jose Antonio Guzmán Quesada ◽  
Michael Hesketh ◽  
...  

2020 ◽  
Author(s):  
Nan Jiang ◽  
Yan Xu ◽  
Tianhe Xu

<p>Precipitable water vapor (PWV) is an important parameter reflecting the amount of solid water in the atmosphere, which is widely utilized in the studies of numerical weather prediction (NWP) and climate change. The microwave radiance measurements made by the space-based remote sensing satellites give us the opportunity to make the climate studies on a global scale. So far, PWV retrieval over the ocean has a long data record and the technology is very mature, but in the case of PWV retrieval over land, it is more challenging to isolate the atmospheric signals from the varied surface signals. In this study, we will apply a new retrieval method over land based on the dual-polarized difference (vertical and horizontal) at 19 GHz and 23 GHz using the brightness temperatures from the Global Change Observation Mission-Water (GCOM-W)/Advanced Microwave Scanning Radiometer 2 (AMSR2). We found polarization difference in brightness temperatures has an exponential relation on the amount of PWV. The validation results of the PWV retrieval from the ground-based GNSS stations show that the proposed method has a mean accuracy of 3.9 mm. Thus, the proposed method can give a possibility to improve the accuracy of data assimilation in the NWP applications and is useful for the studies of global climate change with the long-term data records.</p>


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