• Energy Research

Spatial assessments of historical climate change are of paramount importance to focus research and conservation efforts. Despite the fact that there are global climatic databases available at high spatial resolution, they present some shortcomings to evaluate historic trends of climate change and their impacts on biodiversity. These databases span over a single period in the late 20th and early 21th centuries and their quality and reliability in many regions is compromise because they have not been produce with all information available for all regions. Therefore, in this contribution we developed climatic surfaces for Mexico for three periods that cover most of the 20th and early 21th centuries: t1-1940 (1910-1949), t2-1970 (1950-1979) and t3-2000 (1980-2009), and characterize climate change rates of the biogeographic provinces of Mexico via a linear trend analysis of monthly values and a Mann-Kendall analysis. Our results indicate that rates of change and trends have not been uniform across Mexico: Nearctic provinces had suffered higher and more consistent trends of change than southern tropical regions. Central and southern provinces cooled down at the beginning of the 20th century, but warmed up consistently since the 1970s. Precipitation has generally increased throughout the country, being more notorious in northern provinces. We aim to provide modellers with a set of climate surfaces that may help decision-making to improve management strategies for biodiversity conservation.

Veterinaria México OA ISSN: 2448-6760Cite this as:Zarza H, Martínez-Meyer E, Suzán G, Ceballos G. Geographic distribution of Desmodus rotundus in Mexico under current and future climate change scenarios: Implications for bovine paralytic rabies infection. Veterinaria México OA. 2017;4(3). doi: 10.21753/vmoa.4.3.390.Climate change may modify the spatial distribution of reservoirs hosting emerging and reemerging zoonotic pathogens, and forecasting these changes is essential for developing prevention and adaptation strategies. The most important reservoir of bovine paralytic rabies in tropical countries, is the vampire bat (Desmodus rotundus). In Mexico, the cattle industry loses more than $2.6 million US dollar, annually to this infectious disease. Therefore, we predicted the change in the distribution of D. rotundus due to future climate change scenarios, and examined the likely effect that the change in its distribution will have on paralytic rabies infections in Mexico. We used the correlative maximum entropy based model algorithm to predict the potential distribution of D. rotundus. Consistent with the literature, our results showed that temperature was the variable most highly associated with the current distribution of vampire bats. The highest concentration of bovine rabies was in Central and Southeastern Mexico, regions that also have high cattle population densities. Furthermore, our climatic envelope models predicted that by 2050–2070, D. rotundus will lose 20 % of its current distribution while the northern and central regions of Mexico will become suitable habitats for D. rotundus. Together, our study provides an advanced notice of the likely change in spatial patterns of D. rotundus and bovine paralytic rabies, and presents an important tool for strengthening the National Epidemiological Surveillance System and Monitoring programmes, useful for establishing holistic, long-term strategies to control this disease in Mexico.Figure 4. Modelled suitability for future distribution of Desmodus rotundus according to Global Climate Model GFDL-CM3 for two time periods (2050 and 2070), and two Representative Concentration Pathways (RCP 4.5 and 8.5). Left-hand column shows suitability values, with blue indicating more suitable conditions.

Le changement d'utilisation des terres/de couverture est la principale cause de dégradation des écosystèmes terrestres. Cependant, ses impacts seront exacerbés en raison du changement climatique et de la croissance démographique, entraînant une expansion agricole en raison de la demande accrue de denrées alimentaires et de la baisse des rendements agricoles dans certaines zones tropicales. Les stratégies internationales visant à atténuer les impacts du changement climatique et du changement du couvert terrestre sont difficiles dans les régions en développement. Cette étude vise à évaluer des alternatives pour minimiser les impacts de ces menaces dans le cadre de trajectoires socio-économiques, dans l'une des régions les plus biologiquement riches du Guatemala et du Mexique. Cette étude est située dans le bassin versant d'Usumacinta, une région transfrontalière qui partage une histoire commune, avec des propriétés biophysiques et des contraintes économiques similaires qui ont conduit à d'importants changements dans l'utilisation/la couverture des terres. Pour comprendre les impacts sur la déforestation et les émissions de carbone des différentes pratiques de gestion des terres, nous avons développé trois scénarios (1) : le statu quo (BAU), (2) un scénario de réduction des émissions visant à réduire la déforestation et la dégradation (REDD+) et (3) zéro déforestation à partir de 2030 sur la base des engagements internationaux. Nos résultats suggèrent que d'ici 2050, la couverture terrestre naturelle pourrait réduire de 22,3 et 12,2% son étendue dans les scénarios BAU et REDD +, respectivement par rapport à 2012. Cependant, le scénario zéro déforestation montre que d'ici 2050, il serait possible d'éviter de perdre 22,4 % du bassin versant boisé (1,7 million d'hectares) et d'en récupérer 5,9 % (0,4 million d'hectares). En termes de séquestration du carbone, les projets REDD + peuvent réduire les pertes de carbone dans la végétation naturelle, mais une politique de zéro déforestation peut doubler la séquestration du carbone produite par les projets REDD + uniquement. Cette étude montre que pour réduire les pressions sur les écosystèmes, en particulier dans les régions fortement marginalisées avec des migrations importantes, il est nécessaire de mettre en œuvre des politiques transfrontalières de gestion des terres qui intègrent également des stratégies de réduction de la pauvreté. El cambio en el uso/cobertura de la tierra es la principal causa de la degradación de los ecosistemas terrestres. Sin embargo, sus impactos se exacerbarán debido al cambio climático y al crecimiento de la población, impulsando la expansión agrícola debido a una mayor demanda de alimentos y menores rendimientos agrícolas en algunas áreas tropicales. Las estrategias internacionales destinadas a mitigar los impactos del cambio climático y el cambio en la cobertura del uso de la tierra son un desafío en las regiones en desarrollo. Este estudio tiene como objetivo evaluar alternativas para minimizar los impactos de estas amenazas bajo trayectorias socioeconómicas, en una de las regiones biológicamente más ricas de Guatemala y México. Este estudio se encuentra en la cuenca de Usumacinta, una región transfronteriza que comparte una historia común, con propiedades biofísicas y limitaciones económicas similares que han llevado a grandes cambios en el uso/cobertura de la tierra. Para comprender los impactos en la deforestación y las emisiones de carbono de las diferentes prácticas de gestión de la tierra, desarrollamos tres escenarios (1): negocios como siempre (BAU), (2) un escenario de reducción de emisiones destinado a reducir la deforestación y la degradación (REDD+) y (3) cero deforestación a partir de 2030 en función de los compromisos internacionales. Nuestros resultados sugieren que para 2050, la cobertura natural de la tierra podría reducir el 22.3 y el 12.2% de su extensión bajo los escenarios BAU y REDD +, respectivamente, en comparación con 2012. Sin embargo, el escenario de deforestación cero muestra que para 2050, sería posible evitar la pérdida del 22,4% de la cuenca forestal (1,7 millones de ha) y recuperar el 5,9% (0,4 millones de hectáreas) de la misma. En términos de secuestro de carbono, los proyectos REDD + pueden reducir las pérdidas de carbono en la vegetación natural, pero una política de deforestación cero puede duplicar el secuestro de carbono producido solo por los proyectos REDD +. Este estudio muestra que para reducir las presiones sobre los ecosistemas, particularmente en regiones altamente marginadas con una migración significativa, es necesario implementar políticas transfronterizas de gestión de la tierra que también integren estrategias de alivio de la pobreza. Land-use/cover change is the major cause of terrestrial ecosystem degradation. However, its impacts will be exacerbated due to climate change and population growth, driving agricultural expansion because of higher demand of food and lower agricultural yields in some tropical areas. International strategies aimed to mitigate impacts of climate change and land use-cover change are challenging in developing regions. This study aims to evaluate alternatives to minimize the impacts of these threats under socioeconomic trajectories, in one of the biologically richest regions in Guatemala and Mexico. This study is located at the Usumacinta watershed, a transboundary region that shares a common history, with similar biophysical properties and economic constraints which have led to large land use/cover changes. To understand the impacts on deforestation and carbon emissions of different land-management practices, we developed three scenarios (1): business as usual (BAU), (2) a reducing emissions scenario aimed to reduce deforestation and degradation (REDD+), and (3) zero-deforestation from 2030 onwards based on the international commitments. Our results suggest that by 2050, natural land cover might reduce 22.3 and 12.2% of its extent under the BAU and REDD + scenarios, respectively in comparison with 2012. However, the zero-deforestation scenario shows that by 2050, it would be possible to avoid losing 22.4% of the forested watershed (1.7 million ha) and recover 5.9% (0.4 million hectares) of it. In terms of carbon sequestration, REDD + projects can reduce the carbon losses in natural vegetation, but a zero-deforestation policy can double the carbon sequestration produced by REDD + projects only. This study shows that to reduce the pressures on ecosystems, particularly in regions highly marginalized with significant migration, it is necessary to implement transboundary land-management policies that also integrate poverty alleviation strategies. استخدام الأراضي/تغيير الغطاء هو السبب الرئيسي لتدهور النظام الإيكولوجي الأرضي. ومع ذلك، ستتفاقم آثاره بسبب تغير المناخ والنمو السكاني، مما يؤدي إلى التوسع الزراعي بسبب ارتفاع الطلب على الغذاء وانخفاض الغلة الزراعية في بعض المناطق الاستوائية. تشكل الاستراتيجيات الدولية الرامية إلى التخفيف من آثار تغير المناخ وتغير استخدام الأراضي تحدياً في المناطق النامية. تهدف هذه الدراسة إلى تقييم البدائل لتقليل آثار هذه التهديدات في إطار المسارات الاجتماعية والاقتصادية، في واحدة من أغنى المناطق بيولوجيًا في غواتيمالا والمكسيك. تقع هذه الدراسة في مستجمع مياه أوسوماسينتا، وهي منطقة عابرة للحدود تشترك في تاريخ مشترك، مع خصائص فيزيائية حيوية مماثلة وقيود اقتصادية أدت إلى تغييرات كبيرة في استخدام الأراضي/تغطيتها. لفهم تأثيرات ممارسات إدارة الأراضي المختلفة على إزالة الغابات وانبعاثات الكربون، وضعنا ثلاثة سيناريوهات (1): العمل كالمعتاد (BAU)، (2) سيناريو خفض الانبعاثات الذي يهدف إلى الحد من إزالة الغابات وتدهورها (REDD+)، و (3) إزالة الغابات الصفرية اعتبارًا من عام 2030 فصاعدًا بناءً على الالتزامات الدولية. تشير نتائجنا إلى أنه بحلول عام 2050، قد يقلل الغطاء الأرضي الطبيعي بنسبة 22.3 و 12.2 ٪ من مداه في إطار سيناريو العمل الاعتيادي وسيناريو خفض الانبعاثات الناجمة عن إزالة الغابات وتدهورها في البلدان النامية، على التوالي مقارنة بعام 2012. ومع ذلك، يُظهر سيناريو إزالة الغابات الصفرية أنه بحلول عام 2050، سيكون من الممكن تجنب فقدان 22.4 ٪ من مستجمعات المياه الحرجية (1.7 مليون هكتار) واستعادة 5.9 ٪ (0.4 مليون هكتار) منها. من حيث عزل الكربون، يمكن لمشاريع خفض الانبعاثات الناجمة عن إزالة الغابات وتدهورها في البلدان النامية أن تقلل من خسائر الكربون في الغطاء النباتي الطبيعي، ولكن سياسة إزالة الغابات الصفرية يمكن أن تضاعف عزل الكربون الناتج عن مشاريع خفض الانبعاثات الناجمة عن إزالة الغابات وتدهورها في البلدان النامية فقط. تُظهر هذه الدراسة أنه للحد من الضغوط على النظم الإيكولوجية، لا سيما في المناطق المهمشة للغاية مع الهجرة الكبيرة، من الضروري تنفيذ سياسات إدارة الأراضي العابرة للحدود التي تدمج أيضًا استراتيجيات التخفيف من حدة الفقر.

Climate change is recognized as an important threat to global biodiversity because it increases the risk of extinction of many species on the planet. Mexico is a megadiverse country and native tree species such as red cedar (Cedrela odorata) can be used to maintain forests while helping mitigate climate change, because it is considered a fast growing pioneer species with great economic potential in the forestry industry. In order to assess possible shifts in areas suitable for C. odorata plantations in Mexico with ecological niche models, we used the MaxLike algorithm, climate variables, the geo-referenced records of this species, three general circulation models and three scenarios of future emissions. Results show a current potential distribution of 573,079 km2 with an average probability of occurrence of 0.93 (± 0.13). The potential distribution area could increase up to 650,356 km2 by 2060 according to the general circulation model HADCM3 B2, with an average probability of occurrence of 0.86 (± 0.14). Finally, we delimited an area of 35,377 km2 that has a high potential for the establishment of C. odorata plantations, by selecting those sites with optimal conditions for its growth that are outside protected areas and are currently devoid of trees. C. odorata has a significant potential to help in the mitigation of the effects of climate change. Using MaxLike we identified extense areas in Mexico suitable to increase carbon sequestration through plantations of this highly valued native tree species.

Demographic analyses and ecological niche modeling (ENM) are two popular tools that address species persistence in relation to environmental conditions. Classic demography provides detailed information about the mechanisms that allow a population to grow or remain stable at a local scale, while ENM infers distributions from conditions suitable for species persistence at geographic scales by relating species' occurrences with environmental variables. By integrating these two tools, we may better understand population processes that determine species persistence at a geographic scale. To test this idea, we developed a model that relates climate to demography of the cactus Opuntia rastrera using 15 years of data from one locality. Using this model we determined the geographic area where populations would have positive growth rates given its climatic conditions. The climate-dependent demographic model showed poor performance as a distribution model, but it was helpful in defining some mechanisms that determine species' distributions. For instance, high rainfall had a negative impact on the population growth rate by increasing mortality. Rainy areas to the west of the distribution of O. rastrera were identified as unsuitable both by our climate-dependent demographic model and by a popular ENM algorithm (MaxEnt), suggesting that distribution is constrained by excessive rains due to high mortality. Areas projected to be climatically suitable by MaxEnt were not related with higher population growth rates. Instead, we found a strong correlation between environmental distance to the niche centroid (center of the niche hypervolume, where optimal conditions may occur) and population growth rate, meaning that the niche centroid approach is helpful in finding high-fitness areas.

AbstractClimate change is expected to be a significant threat to biodiversity, including crop diversity at centers of origin and diversification. As a way to avoid food scarcity in the future, it is important to have a better understanding of the possible impacts of climate change on crops. We evaluated these impacts on maize, one of the most important crops worldwide, and its wild relatives Tripsacum and Teocintes. Maize is the staple crop in Mexico and Mesoamerica, and there are currently about 59 described races in Mexico, which is considered its center of origin . In this study, we modeled the distribution of maize races and its wild relatives in Mexico for the present and for two time periods in the future (2030 and 2050), to identify the potentially most vulnerable taxa and geographic regions in the face of climate change. Bioclimatic distribution of crops has seldom been modeled, probably because social and cultural factors play an important role on crop suitability. Nonetheless, rainfall and temperature still represent a major influence on crop distribution pattern, particularly in rainfed crop systems under traditional agrotechnology. Such is the case of Mexican maize races and consequently, climate change impacts can be expected. Our findings generally show significant reductions of potential distribution areas by 2030 and 2050 in most cases. However, future projections of each race show contrasting responses to climatic scenarios. Several evaluated races show new potential distribution areas in the future, suggesting that proper management may favor diversity conservation. Modeled distributions of Tripsacum species and Teocintes indicate more severe impacts compared with maize races. Our projections lead to in situ and ex situ conservation recommended actions to guarantee the preservation of the genetic diversity of Mexican maize.

Evaluation of various climate change factors on Mexican bird populations shows temperature has the strongest influence.