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Fire scar analysis is a fundamental tool for reconstructing fire regimes in conifer forests. However, little is known about fire scar properties in tropical montane conifers, where some assumptions limit dendroecological research. These include that fir species do not exhibit external fire scars and that pines without external fire scars have not experienced past fires. This study describes fire scar patterns in two conifer species growing in Mexican temperate forests: sacred fir (Abies religiosa) and smooth-bark Mexican pine (Pinus pseudostrobus). We extracted cross-sections from 110 trees and measured tree age, basal diameter, bark thickness, fire scar size and seasonality, the number of scars per tree, years and basal diameter from pith to the first scar, and the proportion of external and buried fire scars. Most trees had three fire scars, which appeared during the dry season after the first 15 years measured from the pith. Old and large-diameter trees did not have more fire scars, but the time between fire scars influenced fire scar closure in sacred firs. Bark thickness and the proportion of visible and buried fire scars were similar in both species. Our results suggest that the absence of visible fire scars in smooth-bark Mexican pines does not imply the absence of fire, and sacred firs can exhibit external fire scars like pines.

Landslides are one of the most common and destructive natural hazards in the world. The Sierra-Costa region in the southwestern part of the Michoacan state, Mexico, is prone to landslides because o...

The El Estribo Volcanic Complex, located to the south of Pátzcuaro Lake (Central Mexico), forms an elevation based on a shield volcano crowned by a cinder cone. Two debris avalanches, dated at 28,000 and 14,000 ybp, cover an area of 4 km2 with a typical hummocky topography. The zone is a state natural protected area with no previous studies of hazard and risk from mass movement processes. Herein, we present a detailed geomorphological map of the debris-avalanche area, scale 1:20,000. The approach applied used two hierarchical levels, geomorphological landscapes and landforms. The fault scarp was mapped using high-resolution digital elevation models obtained whit unmanned aerial vehicles (UAV) survey. We describe and characterized four main geomorphological units, 20 subunits, 66 hummocks, and the general drainage network. This map is a valuable tool to identify and quantify risks from mass movement processes.

espanolLa determinacion de criterios acuicolas indicados para el desarrollo de la actividad permite identificar capacidades inherentes de los sitios para ser utilizados bajo este proposito. Se utilizo el proceso de analisis jerarquico con el fin de evaluar la importancia relativa de los criterios definidos con base en la opinion de 12 expertos en el tema. Dicho grupo determino como criterios principales tipo de agua, temperatura, calidad de los organismos, sistema de cultivo, textura de suelo, nivel de tecnologia y eficiencia en la administracion. Los resultados indican que los criterios con mayor importancia fueron agua con una ponderacion de 0.38, temperatura con 0.20 y calidad de los organismos 0.19. La implementacion de la tecnica del proceso de analisis jerarquico demostro ser util para la construccion de un indice global de eficiencia para la actividad acuicola, basado en conocimiento experto. EnglishThe determination of aquaculture criteria indicated for the development of the activity allows identifying the inherent capacities of the sites to be used for this purpose. In this study the hierarchical analysis process was used in order to evaluate the relative importance of the criteria defined based on the opinion of 12 experts on the subject. The group determined as main criteria type of water, temperature, quality of the organisms, cultivation system, soil texture, level of technology and efficiency in administration. The results indicate that the criteria with greater importance were water with 0.38 of weight, temperature with 0.20 and quality of the organisms with 0.19. Implementation of the hierarchical analysis process technique proved to be useful for the construction of a global efficiency index for aquaculture activity, based on expert knowledge.

Volcanic activity can have a significant effect on the growth and survival of trees. The objective of our research was to analyze the effects of the 1855–1856 eruption of the Tacaná volcano and the ashfall from the 1902 eruption of the Santa María volcano, Guatemala, on the radial growth of trees at Tacaná. Dendrochronological sampling was carried out on sites covered by Pinus hartwegii Lindl., and a ring-width chronology was built using 102 increment cores from 75 trees. The ring-width chronology shows two statistically significant suppression events. One of these events occurred from 1857 to 1868 and was potentially caused by the historic eruption of Tacaná (1855–1856). The second suppression event occurred from 1903 to 1908, during which tree growth was affected 1 year after the ashfall caused by the 1902 eruption of Santa María. The growth suppression did not have the same magnitude in all sampled trees and may be related to the thickness of the ash layer deposited around each tree. For the first time, we show that tree growth at Tacaná is reduced by ashfall from volcanic eruptions. Our results may contribute to the evaluation of risks associated with the volcanic activity of the Tacaná volcano.

In the framework of a landslide inventory map of the Sierra Costa Region, we identified and classified landslides on the basis of extensive field-verified aerial photo interpretation. Geological an...

Dendroclimatology has gained relevance during the XXI century. We analyze the state of-the-art of dendroclimatology in Latin America during the past 28 years (1990 to 2019), identifying the current state and recent advances in the application of dendroclimatology in this region. We carried out a systematic review in ScienceDirect, Web of Science, and Scopus databases using Boolean operators to logically connect the keywords “dendrochronology,” “dendroclimatology,” “trend,” “climatic variability,” and “climatic variability trend”, for each country. Dendroclimatological research conducted in the region focused on climatic reconstruction and the evaluation of new tree species with dendrochronological potential, which increase in 2010, then there was a gap between 1995 and 1996, later increase to present. Dendroclimatological studies in Latin America have been mainly developed in temperate climate zones (82.4 %) followed by tropical or subtropical areas (17.6 %). Dendroclimatological research in Latin America has provided advances in the study of climate variability by defining response functions of tree rings to climate. The generated information allows for a better understanding of the spatial and temporal dynamics of climatic variability and about its effects on ecosystems and society. We also call for increased dendroclimatological research based on subtropical and tropical forests limited studied until today.

Maps of natural hazards are essential for the prevention or mitigation of disasters. The Nexpa River mountainous basin is in the Sierra-Costa region of the state of Michoacán, Mexico. The dispersed rural settlements in the basin, accessed through a network of mainly minor roads and tracks, are highly vulnerable in cases of catastrophic hydrometeorological events. Our study aimed to map flood zones and assess flood susceptibility in the basin on the basis of geopedology, topography, land cover and land use, to assess the vulnerability of local rural settlements and their network of roads and tracks. The land morphology was mapped and the weighted overlay technique was applied in a geographic information system to generate maps of susceptibility to flooding. Our results showed that 13% of settlements and 7% of the communication network are within flood zones. Maps based on environmental factors showed low to medium susceptibility to flooding. These methods are useful and effective for zones with little or no hydrometeorological information, and they can provide a robust source of information for decision makers regarding land planning to mitigate flood vulnerability.

Implementing and monitoring long-term conservation strategies demands identifying priorities for preserving landscape connectivity. In this manuscript, we present an approach to prioritize areas for preserving landscape connectivity by using the landscape matrix in central-western Mexico and the connectivity for habitat patches considering ensembles of different terrestrial organisms. We aggregated three multispecies connectivity scenarios into a composite corridor scenario. To evaluate which corridors were more important to multispecies connectivity, we used the composite corridor model based on two ways: (1) the contribution of habitat patches that the corridor connects to overall connectivity and (2) the corridor’s capability for facilitating movement across the network of patches. Habitat patches were classified according to their value for the conservation of multispecies connectivity by hybridizing circuit-based and spatial prioritization models for connectivity conservation. We developed current flow models for each species (n = 40) and combined them in four prioritization models corresponding to the three multispecies groups and an all-species group. We found that the corridors having the highest accumulated importance (CI ≥ 58) are located along the protected areas of Pico de Tancitaro and the Monarch Butterfly Biosphere Reserve (Reserva de la Biosfera de la Mariposa Monarca–RBMM, Spanish acronym), which have relatively similar spatial distributions corridors compared to areas with priority for conservation (relative rank test = 0.6). Within those areas, there are permeable sectors with high connectivity retention values that could optimize their ecological function as multispecies corridors. Our approach is applicable to different landscapes, and it allows for identifying priorities for connectivity conservation by integrating landscape elements outside habitat patches.

Pinus cembroides exhibits an excellent potential for dendrochronological studies on the basis of statistical parameters and its response to climatic variables, in particular seasonal winter–spring precipitation. Studies of forest growth under induced climatic variations allow estimating the intensity of impacts on forest ecosystems and understanding them. In the present study, the climatic response of Pinus cembroides radial increase was evaluated based on precipitation and average temperature (maximum, minimum and mean temperature). The study was carried out in Sierra del Cubo, Guanajuato, in the upper course of the Laja River. A correlation response function analysis was used to evaluate P. cembroides growth in response to climatic factors. Correlation analysis indicates that P. cembroides growth is positively associated with precipitation of October and December of the previous year, as well as with January–February, May–August and October of the current-year precipitation. Regarding temperatures, the average minimum temperature of the previous December and of January and May of the current year favored P. cembroides growth. Mean and maximum average temperature had a negative influence on annual radial growth. Response function analysis indicates that P. cembroides response to precipitation was quite unstable for the 1925–2011 period and possibly affected by climatic anomalies recorded over the last decades. The main climatic factors exerting a dominant effect on P. cembroides radial growth are, first, the winter–spring seasonal rainfall and, second, the average winter temperature. P. cembroides forests in Sierra del Cubo are highly affected by environmental variables, and its habitat could decline if winters tend to be drier and temperatures are higher as it is predicted to occur by Intergovernmental Panel of Climate Change models.

Earlywood (EW) and latewood (LW) chronologies can be used to analyze seasonal climatic variation. We constructed and analyzed total ring (RW), EW, and LW ring growth in Abies religiosa and Pinus pseudostrobus trees from the Monarch Butterfly Biosphere Reserve and evaluated their climatic signal (monthly precipitation and mean average, minimum and maximum temperatures) in the growth of tree rings by correlation and response function analyses. Precipitation during October and December of the previous year and during January, February, April, and May of the year of growth had a positive influence in the growth of both P. pseudostrobus and A. religiosa. Mean maximum temperatures had a negative effect on tree growth in both species. Additionally, growth of A. religiosa was more sensitive to variations of mean, minimum, and maximum temperatures in comparison with P. pseudostrobus, and monthly mean minimum temperature was positively correlated with EW and LW series in A. religiosa. We conclude that EW a...

Riparian systems have been included as a key component in ecosystem management because of their role in buffering the impact of land-use activities on fluvial systems. Riparian knowledge can be enhanced with a typology that reflects the multiple relationships occurring throughout the landscape. We propose a hierarchical procedure based on biophysical aspects for building local to regional typologies for guiding research and management, using the Cuitzmala River Basin as a case study. The variables involved were obtained from geospatial databases, water balances, and topographic profiles. The levels and variables are context (altitude, geoform [mountains/hills/plains], and runoff coefficient), structure (stream order, longitudinal slope, hydroperiod, and segment length), and microstructure (lateral slope, bankfull width, and length-to-width ratio). We consider humidity and functional gradient along the basin to identify groups of streams and fluvial networks. Inside each network, we described struc...

The recovery of vegetation cover is a process that has important implications for the conservation of biodiversity and ecosystem services. Generally, the recovery of vegetation cover is documented over large areas using remote sensing, and it is often assumed that ecosystem properties and processes recover along with remotely sensed canopy cover. Here we analyze and compare the structure, composition, and diversity of trees and shrubs among plots established in a stratified random sampling design over four remotely sensed canopy cover change (CCC) categories defined according to a gradient in the percent of canopy cover. Plots were located in the Lake Cuitzeo basin (Mexico), where canopy recovery associated with agricultural abandonment has occurred in recent decades (1975–2000). We found that diversity measures, basal area, tree and shrub density, ground-truthed canopy cover, and mean plant height increased with increasing CCC category. However, Shannon index (H′) was lower in the CCC category with the most closed canopy cover category than in plots apparently not affected by agriculture. Furthermore, ordination analyses showed that composition of dominant species were not associated with CCC categories. Our results suggest that canopy closure in our study area is not associated with the recovery of species diversity, and does not result in similar species dominance as in sites not affected by agriculture.

Anthropogenic changes during the past 2000 years in the Teotihuacan Valley imply that intensity of soil degradation varies depending on the land management practices and the intensity of soil use. As a part of a broader effort to reconstruct erosion dynamics in the Teotihuacan Valley through geoarchaeological approaches, our study applies a process-based watershed hydrology and upland erosion model, the Water Erosion Prediction Project (WEPP). The Geo-spatial interface for WEPP (GeoWEPP) was used to characterize locations of soil detachment and sediment deposition predicted in the watershed through time, based on current and reconstructed conditions in the valley. Climate, topography, soil and land use were used as inputs to WEPP to estimate surface runoff and soil loss rates for periods with different environmental and anthropogenic conditions: the Teotihuacan period (1–650 CE), the Aztec period (1325–1521 CE) and for modern times (after 1970 CE). Over a simulated and established timeframe for those periods, surface runoff and rate of soil loss were estimated to be higher during the Aztec period, when the area devoted to agriculture dominated the landscape. Land use change had a major impact on soil erosion. Comparison of the pre-Hispanic periods with current conditions shows that WEPP is useful in showing the roles of management and climate in environmental degradation. The results contribute to the scientific debate about the antiquity and causes of erosion in central Mexico. The research shows that land use is one of the foremost factors affecting soil erosion, both in ancient and modern periods, with particular impact during the Aztec period.

Evaluating the cumulative effects of the human footprint on landscape connectivity is crucial for implementing policies for the appropriate management and conservation of landscapes. We present an adjusted multidimensional spatial human footprint index (SHFI) to analyze the effects of landscape transformation on the remnant habitat connectivity for 40 terrestrial mammal species representative of the Trans-Mexican Volcanic System in Michoacan (TMVSMich), in western central Mexico. We adjusted the SHFI by adding fragmentation and habitat loss to its original three components: land use intensity, time of human landscape intervention, and biophysical vulnerability. The adjusted SHFI was applied to four scenarios: one grouping all species and three grouping several species by habitat spatial requirements. Using the SHFI as a dispersal resistance surface and applying a circuit theory based approach, we analyzed the effects of cumulative human impact on habitat connectivity in the different scenarios. For evaluating the relationship between habitat loss and connectivity, we applied graph theory-based equivalent connected area (ECA) index. Results show over 60% of the TMVSMich has high SHFI values, considerably lowering current flow for all species. Nevertheless, the effect on connectivity of human impact is higher for species with limited dispersal capacity (100–500 m). Our approach provides a new form of evaluating human impact on habitat connectivity that can be applied to different scales and landscapes. Furthermore, the approach is useful for guiding discussions and implementing future biodiversity conservation initiatives that promote landscape connectivity as an adaptive strategy for climate change.

Nature’s complexity is intriguing, but the circumstances determining whether or how order emerges from such complexity remains a matter of extensive research. Using the geographical distributions and food preferences of all terrestrial mammal species with masses >3 kg, we show that large mammals group into feeding guilds (species exploiting similar resources) and that these guilds form trophic structures that vary across biomes globally. We identify five trophic structures closely matching climate variability and named them boreal, temperate, semiarid, seasonal tropical and humid tropical owing to their relative overlap with the distribution of biomes. We also find that human activities simplify trophic structures, generally transitioning them to species-poorer states. Detected transitions include boreal and temperate structures becoming depauperate or seasonal- and humid-tropical becoming semiarid. Whether the observed generalities among trophic structures of large mammals are indicative of patterns across whole food webs is matter for further investigation. The results help refine projections of the effects of environmental change on the trophic structure of large mammals., M.M. was originally funded through 1/SAESCTN/ALENT-07–0224-FEDER-001755 led by MBA. MBA also thanks a Portuguese Foudation for Science and Technology project PTDC/ AAG-MAA/3764/2014. Both are now funded through the Spanish Ministry of Science, Innovation, and Universities (PGC2018–099363-B-I00).

Los “bosques mesófilos de montaña” son ecosistemas que se caracterizan por el nivel de estratos arbóreos, abundantes helechos y epífitas. Actualmente esta formación vegetal se encuentra en forma de relictos en algunas de las cañadas del país, por lo que es importante conservar este ecosistema que ocupa menos de 1% del territorio nacional y que tiene un alto valor ante la escasez de agua y la pérdida de los bosques. Su importancia ecológica radica en la alta diversidad de flora y la presencia de especies endémicas en peligro de extinción que funcionan como cubierta protectora para evitar la erosión. Su importancia hidrológica deriva de la presencia de lluvias y nubosidad, neblina o niebla durante gran parte del año que reduce la incidencia de radiación solar disminuyendo las salidas de agua por evapotranspiración. Además, al ingreso de precipitación por lluvia hay que adicionar la precipitación horizontal de la niebla interceptada por el dosel. En este trabajo se presenta una revisión bibliográfica de los estudios realizados en México mediante búsquedas específicas y especializadas en buscadores académicos (Web of science, ScienceResearch, Academia.edu y Google scholar). Se encontró un alto índice de publicaciones de investigación ecológica en torno a la biodiversidad (fauna, listados florísticos y estructura de la vegetación), perturbación, sucesión secundaria, restauración ecológica; sin embrago, se identificaron un número limitado de trabajos sobre servicios ecosistémicos (hidrológicos y captura de carbono) y los más recientes están relacionados al cambio climático.

Understanding the effects of climate on the growth of trees is important to project the response of forests to climate change. Dendrochronological analysis offers a “proxy” source for the effects of climatic variation on tree growth at different spatial and temporal scales. To examine influences of temperature and precipitation on radial growth of Pinus pseudostrobus and Abies religiosa, this study combines measurements of radial growth patterns of forest trees in the Monarch Butterfly Biosphere Reserve (MBBR) in central Mexico with temperature and precipitation variables from instrumental records. Dendrochronological samples were collected as cross sections and increment cores by using a chainsaw and increment borers, respectively. Total ring-width chronologies were developed for each site. Principal component analyses (PCA) were used to identify common temperature, precipitation and tree growth variation patterns. Correlation and response function analyses between chronologies and records of temperature and precipitation were used to evaluate the relation of climate variables on tree growth. The months during which tree growth was most strongly affected by precipitation were January, February and October from the previous year; only the temperature of September from the previous year affected the tree growth. In some chronologies, May’s average monthly maximum temperature was negatively correlated with tree growth. PCA and a comparison of PCA factor scores of climatic variables and chronologies showed no significant differences between northern, central or southern portions of the MBBR. Apparently, tree growth in the MBBR is reduced in years of low January–May precipitation combined with high summer (September of the previous year) temperatures, a scenario which is likely to occur as a consequence of global climate change.

The content of sterols and erythrodiol + uvaol was studied in 273 virgin olive oil samples from 40 mills in five olive-growing zones of Extremadura (Spain). An analysis of variance showed significant differences at a confidence level of 95 % between the different zones in each of the main sterols and in the sum of erythrodiol + uvaol. The results of a linear discriminant analysis, considering the different olive-growing areas as categorical dependent variables and the different sterols as independent variables, explained 78.2 % of the variance with the first two discriminant functions. The resulting model correctly classified 86.9 % of the samples analysed. A validation study was conducted to verify the goodness of the discriminant analysis, resulting in 79.3 % of the new samples used for validation being correctly classified. In the graphical representation of the different groups studied considering the proposed model’s first two discriminant functions, the centroids of the Sierra Norte de Caceres, Vegas del Guadiana and Tierra de Barros olive-growing zones were clearly separated, but this was not the case for the other two zones—La Serena and La Siberia.

Understanding what determines species’ geographic distributions is crucial for assessing global change threats to biodiversity. Measuring limits on distributions is usually, and necessarily, done with data at large geographic extents and coarse spatial resolution. However, survival of individuals is determined by processes that happen at small spatial scales. The relative abundance of coexisting species (i.e. ‘community structure’) reflects assembly processes occurring at small scales, and are often available for relatively extensive areas, so could be useful for explaining species distributions. We demonstrate that Bayesian Network Inference (BNI) can overcome several challenges to including community structure into studies of species distributions, despite having been little used to date. We hypothesized that the relative abundance of coexisting species can improve predictions of species distributions. In 1570 assemblages of 68 Mediterranean woody plant species we used BNI to incorporate community structure into Species Distribution Models (SDMs), alongside environmental information. Information on species associations improved SDM predictions of community structure and species distributions moderately, though for some habitat specialists the deviance explained increased by up to 15%. We demonstrate that most species associations (95%) were positive and occurred between species with ecologically similar traits. This suggests that SDM improvement could be because species co-occurrences are a proxy for local ecological processes. Our study shows that Bayesian Networks, when interpreted carefully, can be used to include local conditions into measurements of species’ large-scale distributions, and this information can improve the predictions of species distributions., This work was funded by FCT Project “QuerCom” (EXPL/AAG-GLO/2488/2013) and the ERA-Net BiodivERsA project “EC21C” (BIODIVERSA/0003/2011). A.M.N. was supported by a Bolsa de Investigacao de Pos-doutoramento (BI_Pos-Doc_UEvora_Catedra Rui Nabeiro_EXPL_AAG-GLO_2488_2013) and postdoctoral fellowships from the Ministry of Economy and Competitivity (FPDI-2013-16266 and IJCI‐2015‐23498). MGM acknowledges support by a Marie Curie Intra-European Fellowship within the 7th European Community Framework Programme (FORECOMM). J. Vicente is supported by POPH/FSE funds and by National Funds through FCT - Foundation for Science and Technology under the Portuguese Science Foundation (FCT) through Post-doctoral grant SFRH/BPD/84044/2012. AE has a postodoctoral contract funded by the project CN-17-022 (Principado de Asturias, Spain).

Understanding what determines species’ geographic distributions is crucial for assessing global change threats to biodiversity. Measuring limits on distributions is usually, and necessarily, done with data at large geographic extents and coarse spatial resolution. However, survival of individuals is determined by processes that happen at small spatial scales. The relative abundance of coexisting species (i.e. ‘community structure’) reflects assembly processes occurring at small scales, and are often available for relatively extensive areas, so could be useful for explaining species distributions. We demonstrate that Bayesian Network Inference (BNI) can overcome several challenges to including community structure into studies of species distributions, despite having been little used to date. We hypothesized that the relative abundance of coexisting species can improve predictions of species distributions. In 1570 assemblages of 68 Mediterranean woody plant species we used BNI to incorporate community structure into Species Distribution Models (SDMs), alongside environmental information. Information on species associations improved SDM predictions of community structure and species distributions moderately, though for some habitat specialists the deviance explained increased by up to 15%. We demonstrate that most species associations (95%) were positive and occurred between species with ecologically similar traits. This suggests that SDM improvement could be because species co-occurrences are a proxy for local ecological processes. Our study shows that Bayesian Networks, when interpreted carefully, can be used to include local conditions into measurements of species’ large-scale distributions, and this information can improve the predictions of species distributions.

The study of landscape connectivity in conservation has increased considerably since the early part of the 21st century. While the implications of landscape connectivity are self-evident for conservation, they are also important for physical geography since a proper understanding of landscape patterns and processes allows for better landscape management practices, which are at the core of geography. This paper presents a review of the literature based on 162 publications from 2000 to 2013, in which we evaluated the current state and recent advances in the integration of landscape connectivity in the identification and planning of conservation areas. The literature review and data analysis were based on a database organized into five categories: General information, study areas, research objectives, research methods in connectivity studies, and integration of connectivity with conservation. We found a substantial increase in the number of publications relating to connectivity and conservation from 2008 to 2013. Least cost analysis was the method most commonly applied. We found no implementation of landscape connectivity proposals generated by the studies (e.g. potential corridors) into real landscape elements to ensure the permanence and functionality of ecosystems. We identified four important niches for potential future research projects: a) connectivity and climate change, b) contribution of connectivity studies to restoration planning, c) connectivity and land cover/land use change modeling and planning, d) contribution of connectivity analysis in the provision of ecosystem services across landscapes.

Alluvial fans and terraces develop in diverse regions responding to different tectonic and climatic conditions. The Motozintla basin is located in the State of Chiapas, southern Mexico and has an E–W orientation following the trace of the left-lateral Polochic Fault. The evolution of the Motozintla basin and the alluvial plain is related to several factors, such as fault movement, intense erosion by hydrometeorological events, and anthropogenic activity. This study presents the geomorphology of the alluvial plain that between the villages of Motozintla and Mazapa de Juarez exposes 31 alluvial fans, 5 hanging terraces and 13 ramps. Fourteen of these alluvial fans have been truncated by the Polochic fault, exposing maximum uplifts of ~ 12 m. The internal structure of truncated fans consists of single massive beds (monolithologic fans) or stacked beds (polygenetic fans). The fans' stratigraphy is made of debris flow deposits separated by paleosols and minor hyperconcentrated flows, fluviatile beds, and pyroclastic fall deposits. The reconstruction of the stratigraphy assisted by radiocarbon geochronology suggests that these fans have been active since late Pleistocene (25 ka) to the present. This record suggests that at least 10 events have been recorded at the fan interior during the past ~ 1840 years. One of these events at 355 ± 65 14 C yrs. BP (cal yrs. AD 1438 to 1652) can be correlated across the fans and is likely associated with an extreme hydrometeorologic event. The presence of a 165 ± 60 14 C yrs. BP (cal yrs. AD 1652–1949) debris flow deposit within the fans suggests that movement along the Polochic fault formed the fans' scarp afterwards. In fact, a historic earthquake along the fault occurred east of Motozintla on July 22, 1816 with a M w of 7.5–7.75. Recent catastrophic floods have affected Motozintla in 1998 and 2005 induced by extreme hydrometeorological events and anthropogenic factors. Therefore, scenarios for Motozintla involved several types of mass movement processes that pose a serious hazard and threat to the inhabitants of the region.

La reserva de la biósfera Zicuirán-Infiernillo se estableció debido a su extraordinaria riqueza en bio y geodiversidad; sin embargo, la región se caracteriza por un alto grado de marginación de la problación. Este mapa tiene como objetivo mostrar la conversación e intensidad de uso de la tierra, considerando la afectación a la vegetación natural.

Lake Cuitzeo basin is an important ecological area subjected to strong human pressure on forest covers that are key elements for the long-term support of biodiversity. We studied landscape connectivity changes for the years 1975, 1996, 2000, 2003 and 2008 to identify potential conservation areas in the basin. We modeled potential distributions of the Mexican bobcat ( Lynx rufus escuinapae ) and the ringtail ( Bassariscus astutus ) – two terrestrial mammal focal species with contrasting dispersal capacities – and we determined their habitat availability and suitability in the basin. We then identified their optimal habitat patches and produced landscape cumulative resistance maps, estimated least-cost paths (graph theory approach), and elaborated current flow maps (circuit theory approach). For evaluation of landscape connectivity, we applied an integral index of connectivity (IIC) to each study period, and determined individual habitat patch contribution to the overall landscape connectivity. The IIC index had very low values associated with reduced availability of focal species habitat. However, our study showed the conservation importance of the surface of optimal habitat patch areas. The combined application of a graph-based approach and current flow mapping were useful, and complementary both in terms of estimating potential dispersal corridors and identifying high probability dispersal areas. This indicated that landscape connectivity analysis is a useful tool for identification of potential conservation areas and for local landscape planning.

We propose a global index of impact based on the relative vulnerability of the local population of every species and the further application of regression trees globally optimized with evolutionary algorithms to study the fishing impact on the cartilaginous fish in southeastern Spain. The fishing impact is much higher in areas of less than 40 m depth within 11 km of the Cape Palos marine reserve. The impact also depends on the state of the sea and the kind of habitat. Deep-sea habitats associated with hard substrata and sandy beds show the highest impact, and sublittoral muds and habitats associated with circa littoral rocks with moderate energy show the lowest impact. The fishing impact changes throughout the moon cycle, showing different day-scale patterns associated with different habitats and different species compositions. Finally, we show that the global optimization of the regression trees can be essential to find some important patterns and that these trees are a useful tool for determining which areas are considered to be more important in terms of protection, taking into account specifically the vulnerability of the local populations. Proponemos un índice global de impacto basado en la vulnerabilidad relativa de las poblaciones locales de cada una de las especies y la posterior aplicación de árboles de regresión globalmente optimizados con algoritmos evolutivos, para estudiar el impacto de la pesca en los peces cartilaginosos del sureste español. El impacto de la pesca es mucho mayor, dentro de los 11 km de la reserva marina de Cabo de Palos, en aquellas zonas de menos de 40 m de profundidad. El impacto también depende del estado de la mar y el tipo de hábitat. Los hábitats de aguas profundas asociados a sustrato duro y fondo arenoso muestran los máximos impactos, mientras que, tanto los fondos fangosos sublitorales como los hábitats rocosos circalitorales con moderada energía de las corrientes, muestran un menor impacto. Además, se dan cambios a lo largo del ciclo lunar en el impacto de la pesca, lo que significa que existen diferentes patrones diarios, asociados a distintos hábitats, con distinta composición específica. Finalmente, mostramos que la optimización global de los árboles de regresión es esencial para revelar patrones importantes y son una herramienta útil para determinar aquellas áreas mas importantes en términos de protección, teniendo en cuenta, concretamente, la vulnerabilidad de las poblaciones locales.

It is well-established that changes in land cover and land use (LCLU) are relevant to current local and global changes that are directly linked with food security, human health, urbanization, biodiversity, trans-border migration, environmental refuges, water and soil quality, runoff and sedimentation rates, and other processes. This paper examines LCLU change processes within the Cointzio watershed (Central Mexico). The analysis covers a 28-year time period from 1975 to 2003. LCLU changes were deduced from multi-temporal remote sensing analyses (1975, 1986, 1996, 2000 and 2003). Nearly all of the LCLU changes experienced in the Cointzio watershed occurred during the 1986-1996 period. Half of the 665 km² of the watershed have changed during this period, in what corresponds to a ten-fold increase in the rate of change as compared to the 1975-1986 and 1996-2003 periods. These massive changes are probably related to the Immigration Reform and Control Act (IRCA) of 1986, which limited the transit of undocumented Mexican workers to the United States of America. The methodology applied in this research constitutes a low-cost alternative for evaluating the impact of LCLU change in watersheds. The magnitude of land use change differed during the periods of analyses in the watershed, functional zones and geoforms. The methodological approach applied in this analysis integrates standard procedures to evaluate land cover and land use change in watersheds. Due to the practical value of the results, the data and information generated during the analysis have been made available to local authorities. Está bem estabelecido que alterações na cobertura vegetal e o uso da terra (LCLU) têm um papel relevante nos atuais processos de mudanças locais e globais, dos quais estão diretamente vinculados com a segurança alimentar, a saúde humana, a urbanização, a biodiversidade, a migração transfronteiriça, os refúgios ambientais, a qualidade da água e do solo, o escoamento e taxas de sedimentação, entre outros processos. Este trabalho objetivou analisar os processos de mudança de LCLU dentro da bacia hidrográfica Cointzio (México Central). A análise abrangeu o período de 28 anos entre 1975 e 2003. As mudanças de LCLU foram detectadas por análise multitemporal baseada em técnicas de sensoriamento remoto (1975, 1986, 1996, 2000 e 2003). 46% das mudanças da LCLU ocorreram na bacia hidrográfica Cointzio no período de 1986 a 1996, o que corresponde a um incremento de dez vezes na taxa de mudança em comparação com os períodos 1975-1986 e 1996-2003. Essas modificações massivas estão provavelmente relacionadas com a Reforma da Imigração e a Lei de Controle (IRCA) de 1986, que limitou o trânsito dos trabalhadores mexicanos sem documentos de autorização aos estados Unidos da América. A metodologia aplicada nessa investigação constitui uma alternativa de baixo custo para avaliação do impacto da mudança LCLU em bacias. A magnitude dos processos de mudança de uso da terra varia durante os períodos de análise na bacia hidrográfica, nas zonas funcionais hidrográficas e nas geoformas. O enfoque metodológico aplicado nessa análise integra os procedimentos que avaliam mudanças de cobertura e uso da terra em bacias. Devido à utilidade prática dos resultados, as informações geradas foram colocadas a disposição das autoridades locais com o propósito de apoiar tomadas de decisão.

Landscape connectivity is essential in biodiversity conservation because of its ability to reduce the effect of habitat fragmentation; furthermore is a key property in adapting to climate change. Potential distribution models and landscape connectivity studies have increased with regard to their utility to prioritizing areas for conservation. The objective of this study was to model the potential distribution of Mountain cloud forests in the Transversal Volcanic System, Michoacan and to analyze the role of these areas in maintaining landscape connectivity. Potential distribution was modeled for the Mountain cloud forests based on the maximum entropy approach using 95 occurrence points and 17 ecological variables at 30 m spatial resolution. Potential connectivity was then evaluated by using a probability of connectivity index based on graph theory. The percentage of variation (dPCk) was used to identify the individual contribution of each potential area of Mountain cloud forests in overall connectivity. The different ways in which the potential areas of Mountain cloud forests can contribute to connectivity were evaluated by using the three fractions derived from dPCk (dPCintrak, dPCfluxk, and dPCconnectork). We determined that 37,567 ha of the TVSMich are optimal for the presence of Mountain cloud forests. The contribution of said area in the maintenance of connectivity was low. The conservation of Mountain cloud forests is indispensable, however, in providing or receiving dispersal flows through TVSMich because of its role as a connector element between another habitat types. The knowledge of the potential capacity of Mountain cloud forests to promote structural and functional landscape connectivity is key in the prioritization of conservation areas.