Tropical montane cloud forest is one of the ecosystems with the highest biomass worldwide, representing an important carbon store. Globally its deforestation index is –1.1%, but in Mexico it is higher than –3%. Carb...Tropical montane cloud forest is one of the ecosystems with the highest biomass worldwide, representing an important carbon store. Globally its deforestation index is –1.1%, but in Mexico it is higher than –3%. Carbon estimates are scarce globally, particularly in Mexico. The objective of this study was to simulate future land-cover scenarios for the Sierra Madre Oriental in Mexico, by analyzing past forest cover changes. Another objective was to estimate stored carbon in the two study areas. These objectives involve the generation of information that could be useful inputs to anti-deforestation public policy such as the REDD+ strategy. Remote sensing was used to measure land cover change and estimate carbon stocks. Satellite images from 2015, 2000 and 1986 were used, and Dinamica EGO freeware generatedmodels of future projections. Between 1986 and 2015, 5171 ha of forest were converted to pasture. The annual deforestation rates were –1.5% for Tlanchinol and –1.3% for the San Bartolo Tutotepec sites. Distance to roads and marginalization were highly correlated with deforestation. By 2030, an estimated 3608 ha of forest in these sites will have been converted to pasture. Stored carbon was estimated at 16.35 Mg C ha-1 for the Tlanchinol site and 12.7 Mg C ha-1 for the San Bartolo site. In the Sierra Madre Oriental deforestation due to land cover change(–1.4%) is higher than levels reported worldwide. Besides having high values of stored carbon(14.5 Mg C ha-1), these forests have high biodiversity. The models' outputs show that the deforestation process will continue if action is not taken to avoid the expansion of livestock pasturing. This can be done by paying incentives for forest conservation to the owners of the land. The results suggest that REDD+ is currently the most viable strategy for reducing deforestation rates in tropical montane cloud forests in Sierra Madre Oriental.展开更多
Non-agricultural lands are surveyed sparsely in general.Meanwhile,soils in these areas usually exhibit strong spatial variability which requires more samples for producing acceptable estimates.Capulin Volcano National...Non-agricultural lands are surveyed sparsely in general.Meanwhile,soils in these areas usually exhibit strong spatial variability which requires more samples for producing acceptable estimates.Capulin Volcano National Monument,as a typical sparsely-surveyed area,was chosen to assess spatial variability of a variety of soil properties,and furthermore,to investigate its implications for sampling design.One hundred and forty one composited soil samples were collected across the Monument and the surrounding areas.Soil properties including pH,organic matter content,extractable elements such as calcium (Ca),magnesium (Mg),potassium (K),sodium (Na),phosphorus (P),sulfur (S),zinc (Zn),and copper (Cu),as well as sand,silt,and clay percentages were analyzed for each sample.Semivariograms of all properties were constructed,standardized,and compared to estimate the spatial variability of the soil properties in the area.Based on the similarity among standardized semivariograms,we found that the semivariograms could be generalized for physical and chemical properties,respectively.The generalized semivariogram for physical properties had a much greater sill value (2.635) and effective range (7 500 m) than that for chemical properties.Optimal sampling density (OSD),which is derived from the generalized semivariogram and defines the relationship between sampling density and expected error percentage,was proposed to represent,interpret,and compare soil spatial variability and to provide guidance for sample scheme design.OSDs showed that chemical properties exhibit a stronger local spatial variability than soil texture parameters,implying more samples or analysis are required to achieve a similar level of precision.展开更多
The increasing impact of disasters at local,national,regional and global scales in recent decades has provided enough evidence to urgently direct attention towards the necessity of disaster risk reduction and manageme...The increasing impact of disasters at local,national,regional and global scales in recent decades has provided enough evidence to urgently direct attention towards the necessity of disaster risk reduction and management,and this requires knowledge.Knowledge without communication is barren,and to communicate the risk of disaster it is necessary to understand the perception of the people at risk.In particular,this paper deals with the necessity to delineate strategies of risk communication in pursuance of risk knowledge as a core of disaster risk reduction and management,especially in mountain areas of developing countries.To portray this issue,an analysis of landslide risk perception in terms of experience,landslide risk awareness,exposure,preparedness,and risk communication and trust was undertaken in the municipality of Teziutlán,Puebla,Mexico,an area that has been affected for several decades by episodes of mass movement.Analysis of the responses to a risk perception questionnaire has offered valuable insights in terms of the information and knowledge most required by the people living in the area of interest,in order to devise a realistic and functional strategy to communicate the risk of a landslide disaster.This includes better understanding of controlling factorsand drivers of this risk,and the establishment of potential trusted sources of risk communication.Beyond considering practical matters of risk assessment and management,risk perception and communication can increase the resilience of vulnerable people,and can enhance capacity building for present and future generations.展开更多
This study analyzes six vegetation communities in relation to current climatic parameters and eight climate change scenarios along an elevation gradient extending from 2,710 m to 4,210 m in the Trans-Mexican Volcanic ...This study analyzes six vegetation communities in relation to current climatic parameters and eight climate change scenarios along an elevation gradient extending from 2,710 m to 4,210 m in the Trans-Mexican Volcanic Belt. The projected movements of 25 plant species with the current restricted or wide altitudinal distributions were also modeled. To relate climatic parameters to the species and communities, a Precipitation/Temperature （P/T） index was used both for the current and the different climate-change scenarios. The temperatures are expected to increase by 1.1℃ to 1.7℃ by 2020 and by 2℃ to 3℃ by 2o5o. A decrease of 4% to 13% in the annual precipitation is expected for the 2020 horizon, and a reduction between 3% and 20% is expected for 2050. The reductions in water availability were projected for all altitude levels and plant communities. The most marked reduction was under the HADLEY- A2 scenario, in which the lower limit of the altitudinal range increased from 2,71o to 3,31o m （2050 horizon） with reductions in the P/T index between 36% and 39% compared to the current climate. Most plant species tended to shift their distribution from 20o to 300 m upward in the 2020 temporal horizon scenarios. The Pinus hartwegii, Alnus jorullensis and Pinus montezumae communities would have a shorter altitudinal range as they move upward and merge with the remaining species at the higher altitudinal range. For the 2o5o temporal horizon, 3o% of the species, primarily those from the higher altitudinal range, would disappear because their P/Tindex values would be above the limit of plant survival （〉4,210 m）.展开更多
基金support with doctorate fellowship CONACy T(No.266708)Postgraduate Sciences in Biodiversity and Conservation of the Center for Biological Research,UAEH
文摘Tropical montane cloud forest is one of the ecosystems with the highest biomass worldwide, representing an important carbon store. Globally its deforestation index is –1.1%, but in Mexico it is higher than –3%. Carbon estimates are scarce globally, particularly in Mexico. The objective of this study was to simulate future land-cover scenarios for the Sierra Madre Oriental in Mexico, by analyzing past forest cover changes. Another objective was to estimate stored carbon in the two study areas. These objectives involve the generation of information that could be useful inputs to anti-deforestation public policy such as the REDD+ strategy. Remote sensing was used to measure land cover change and estimate carbon stocks. Satellite images from 2015, 2000 and 1986 were used, and Dinamica EGO freeware generatedmodels of future projections. Between 1986 and 2015, 5171 ha of forest were converted to pasture. The annual deforestation rates were –1.5% for Tlanchinol and –1.3% for the San Bartolo Tutotepec sites. Distance to roads and marginalization were highly correlated with deforestation. By 2030, an estimated 3608 ha of forest in these sites will have been converted to pasture. Stored carbon was estimated at 16.35 Mg C ha-1 for the Tlanchinol site and 12.7 Mg C ha-1 for the San Bartolo site. In the Sierra Madre Oriental deforestation due to land cover change(–1.4%) is higher than levels reported worldwide. Besides having high values of stored carbon(14.5 Mg C ha-1), these forests have high biodiversity. The models' outputs show that the deforestation process will continue if action is not taken to avoid the expansion of livestock pasturing. This can be done by paying incentives for forest conservation to the owners of the land. The results suggest that REDD+ is currently the most viable strategy for reducing deforestation rates in tropical montane cloud forests in Sierra Madre Oriental.
文摘Non-agricultural lands are surveyed sparsely in general.Meanwhile,soils in these areas usually exhibit strong spatial variability which requires more samples for producing acceptable estimates.Capulin Volcano National Monument,as a typical sparsely-surveyed area,was chosen to assess spatial variability of a variety of soil properties,and furthermore,to investigate its implications for sampling design.One hundred and forty one composited soil samples were collected across the Monument and the surrounding areas.Soil properties including pH,organic matter content,extractable elements such as calcium (Ca),magnesium (Mg),potassium (K),sodium (Na),phosphorus (P),sulfur (S),zinc (Zn),and copper (Cu),as well as sand,silt,and clay percentages were analyzed for each sample.Semivariograms of all properties were constructed,standardized,and compared to estimate the spatial variability of the soil properties in the area.Based on the similarity among standardized semivariograms,we found that the semivariograms could be generalized for physical and chemical properties,respectively.The generalized semivariogram for physical properties had a much greater sill value (2.635) and effective range (7 500 m) than that for chemical properties.Optimal sampling density (OSD),which is derived from the generalized semivariogram and defines the relationship between sampling density and expected error percentage,was proposed to represent,interpret,and compare soil spatial variability and to provide guidance for sample scheme design.OSDs showed that chemical properties exhibit a stronger local spatial variability than soil texture parameters,implying more samples or analysis are required to achieve a similar level of precision.
基金the financial support provided by CONACyT through the research project 156242
文摘The increasing impact of disasters at local,national,regional and global scales in recent decades has provided enough evidence to urgently direct attention towards the necessity of disaster risk reduction and management,and this requires knowledge.Knowledge without communication is barren,and to communicate the risk of disaster it is necessary to understand the perception of the people at risk.In particular,this paper deals with the necessity to delineate strategies of risk communication in pursuance of risk knowledge as a core of disaster risk reduction and management,especially in mountain areas of developing countries.To portray this issue,an analysis of landslide risk perception in terms of experience,landslide risk awareness,exposure,preparedness,and risk communication and trust was undertaken in the municipality of Teziutlán,Puebla,Mexico,an area that has been affected for several decades by episodes of mass movement.Analysis of the responses to a risk perception questionnaire has offered valuable insights in terms of the information and knowledge most required by the people living in the area of interest,in order to devise a realistic and functional strategy to communicate the risk of a landslide disaster.This includes better understanding of controlling factorsand drivers of this risk,and the establishment of potential trusted sources of risk communication.Beyond considering practical matters of risk assessment and management,risk perception and communication can increase the resilience of vulnerable people,and can enhance capacity building for present and future generations.
文摘This study analyzes six vegetation communities in relation to current climatic parameters and eight climate change scenarios along an elevation gradient extending from 2,710 m to 4,210 m in the Trans-Mexican Volcanic Belt. The projected movements of 25 plant species with the current restricted or wide altitudinal distributions were also modeled. To relate climatic parameters to the species and communities, a Precipitation/Temperature （P/T） index was used both for the current and the different climate-change scenarios. The temperatures are expected to increase by 1.1℃ to 1.7℃ by 2020 and by 2℃ to 3℃ by 2o5o. A decrease of 4% to 13% in the annual precipitation is expected for the 2020 horizon, and a reduction between 3% and 20% is expected for 2050. The reductions in water availability were projected for all altitude levels and plant communities. The most marked reduction was under the HADLEY- A2 scenario, in which the lower limit of the altitudinal range increased from 2,71o to 3,31o m （2050 horizon） with reductions in the P/T index between 36% and 39% compared to the current climate. Most plant species tended to shift their distribution from 20o to 300 m upward in the 2020 temporal horizon scenarios. The Pinus hartwegii, Alnus jorullensis and Pinus montezumae communities would have a shorter altitudinal range as they move upward and merge with the remaining species at the higher altitudinal range. For the 2o5o temporal horizon, 3o% of the species, primarily those from the higher altitudinal range, would disappear because their P/Tindex values would be above the limit of plant survival （〉4,210 m）.
