Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The mangroves of Laguna de Términos, Campeche have been affected by the loss of hydrological connection due to tropical storms and hurricanes. The objective of this study was to evaluate the natural regeneration in a degraded area, after having implemented actions of restoration through hydrological restoration. Three sampling sites with different times of restoration (1-3 years), and a preserved natural mangrove site as reference, were established. The sampling was carried out in the years 2014 to 2015. Forest structure (density, height), survival, growth rate of seedlings and environmental characteristics were measured. The relationship between the vegetation and environmental characteristics was determined using simple linear regressions and multidimensional scaling analysis. To determine the dispersal of seedlings, a mixed linear model of the seedling density vs distance vs time of restoration was generated. The results showed that distance to natural mangroves affects the seedling density. The phosphates concentration is related to survival, while the ammonia and sulfide concentrationis negatively related to seedling density. The actions of hydrological restoration influenced the settlement and growth seedling of mangrove vegetation, therefore natural areas of mangroves and the water reconnection facilitated propagule dispersal towards the degraded areas, highlighting the importance of the inclusion of natural areas within the restoration projects.

The "tropical mountain cloud forest" are ecosystems characterized by the level of tree strata, abundant ferns and epiphytes. Currently this type of vegetation exists in the form of relicts in some of the country's glens, so it is important to conserve this ecosystem that occupies less than 1% of the national territory and has a high value in the face of water scarcity and forests loss. Its ecological importance lies in the high diversity of flora and the presence of endemic species at threat of extinction, which have a function as a protective cover to prevent soil erosion. Its hydrological importance derives from the presence of rains and cloudiness or fog during several months through the year, which reduces solar radiation incidence by decreasing water outflow associated to evapotranspiration. It is characterized by two inputs; one is rainfall and second is horizontal precipitation, associated to fog which is intercepted by canopy. In this work, a review of the studies carried out in Mexico through specific and specialized searches in online search engines (Web of Science, ScienceResearch, Academia.edu and Google Scholar) is presented. A high number of ecological peer-reviewed research publications was found about biodiversity (fauna, floristic listings and vegetation structure), disturbance, secondary succession, ecological restoration; however, a limited number of works on ecosystem services (hydrological and carbon capture) were identified; the most recent research is related to climate change.

One of the most debated tools for the implementation of sustainable development is “payment for ecosystem services”, of which “payment for watershed services” (PWS) is one of the most developed. While proponents argue that such payments provide market value to the services that ecosystems provide for development, opponents claim that this approach commodifies the environment and promotes inequalities. This article presents an analysis of PWS programs by applying methodologies based on policy coherence for development (PCD), defined as a policy tool aimed at eliminating incoherence within sustainable development strategies that undermine their effectiveness as well as between such strategies and other policy arenas, which are also considered harmful to sustainability. By employing a PCD methodology, the article aims to identify policy mechanisms that undermine PWS programs so that stakeholders can make adjustments, thus, metaphorically ensuring that “the baby” (PWS) is not discarded with “the bathwater” (policy incoherence for sustainable development).

The objective of this work was the proposal of a method that allows quantitative measurement of effects of restoration activities at landscape scale, comparing an initial conservancy condition, with another one ideal, called reference landscape created by projecting the hoped for changes by restoring. Once the reference landscape was defined, an assessment of landscape indexes that allowed measure conservation gain by restoration was proposed. In order to achieve this goal, the work was developed in a basin with high conservation level. The landscape indexes used were: edge effects, diversity landscape index, form index and, spatial continuity index, applying each of them to the initial condition and to the reference landscape. For the studied case, the reference landscape was simple an easily defined, due to the vast amount of information available for the forest in the area. In the stage of landscape index evaluation, those ones with the best performance to measure conservation gain were edge effect and spatial continuity. Form index, instead, created confusing values between initial condition and reference landscape. So too, diversity index forced a complex analysis, mainly because restoration modified the class number between initial conditions and reference landscape.

This research carried out in Tuxtla Gutiérrez, Chiapas between July and November 2016, the objective was to perform a dasometric diagnosis as well as the physical and sanitary conditions of tree alignment in the city. Using a random sampling method on the urban divisions of the city, the species and number of tree, height, diameter, crown coverage, damages and affectations to the urban infrastructure were determined. A total of 7539 trees, distributed in 38 families, 88 genders and 114 species were recorded; 74% of the individuals are introduced, most of the trees have physical and sanitary conditions from regular to good, the most frequent damages are the lifting of sidewalks, exposed roots and interference with aerial wiring. Through this study, the importance of the role that trees play in the cities is confirmed. To ensure the ability to provide environmental services and ensure their sustainability, it is necessary to incorporate integrated management programs for urban trees at the municipal level. Finally, it is important to highlight that in the cities the damage caused to nature due to poorly planned urbanization and accelerated demographic growth are more evident. Undoubtedly, the citizens are the main modelers of change in the urban environment, influencing directly its development.

Bursera simaruba, Lysiloma latisiliquum and Piscidia piscipula are three species of the semi-evergreen tropical forests of Quintana Roo that are valued for their wood. To continue encouraging their use and conservation, as well as their ecological knowledge, it is necessary to determine the annual growth rate and the factors that modulate it. In the present study, the diameter growth of B. simaruba, L. latisiliquum and P. piscipula was measured in a semi-evergreen secondary tropical forest of the Andrés Quintana Roo ejido, Quintana Roo. 73 trees were categorized into five diameter intervals and measured every two months using dendrometric bands. The study ran from January 2011 to May 2012. The increases were correlated with precipitation, average air temperature and local relative humidity. The increases were adjusted to a third-order polynomial model. L. latisiliquum had the highest annual average growth rate (0.18 cm), followed by P. piscipula (0.10 cm) and B. simaruba (0.06 cm). The diametric categories of the three species showed significant differences in their increments, those of 20 cm in general grew more than the rest. The increases correlated significantly (p <0.01) with the temperature in the three species, precipitation and relative humidity did not have a marked influence on the thickening of the bole. The present investigation showed three different patterns of growth, distinguishing temperature as an influencing factor in the increase in diameter.

Semievergreen tropical forest is the most extended forest type and one of the most transformed in the Yucatán Península, however there are few studies addressing its recovery process. The aim of this study was to analyze the recovery patterns of structure, diversity and species composition in a semievergreen tropical forest. The study took place in El Zapotal Conservation Area, in Yucatán, México, between 2011 and 2012. Woody vegetation was sampled in a chronosequence encompassing forest stands of 4 to 60 years of abandonment after cattle grazing, and a remnant conserved (mature) forest. Recovery patterns of structure and diversity were analyzed comparing different nonlinear models, while composition involved ordination and clustering analyses. Structural and diversity attributes increased with successional age, except for density, which peaked at early stages and later declined. Diversity attributes reached values registered in the conserved forest, whereas structural attributes did not. Floristic similarity relative to the mature forest increased with successional age and three groups of species could be distinguished, indicating replacement in species dominance during succession. These results suggest a fast recovery of diversity, a slower recovery of structure, and a pattern of composition more similar to humid tropical forests than to dry forests, with important implications for forest conservation, restoration and climate change mitigation.

This study aimed to investigate the effect of silvicultural systems and of the uses of the soil on the accumulation of the litter, its relation with the recycling and the nutrient supply to the soil, in two areas of Caatinga, in the semi-arid region of Brazil. The first is in the Seridó ecological station; the second is on Pedro Cândido farm. The accumulated litter was collected in the rainy and dry periods with the aid of a litter trap of 0.25 m2, with 16 replicates in each area (4 replicates by silvicultural system). The litter was separated into the fractions of branches, leaves + reproductive structure and miscellaneous, and the values obtained for each fraction were submitted to analysis of variance, according to a randomized block design. For the chemical analysis of litter, samples composed by the four replicates of each fraction referring to each silvicultural system were analyzed, in both evaluated periods. In both periods, in the Seridó ecological station there were 1570 kg ha-1 and 1890 kg ha-1 of litter and 44.18 kg ha-1 and 59.05 kg ha-1 of nutrients returned to soil, respectively. In the Pedro Cândido farm, in both periods, there were 2320 kg ha-1 and 2290 kg ha-1 of litter and 55.86 kg ha-1 and 61.98 kg ha-1 of nutrients recycled to the soil, respectively. The largest accumulation of litter in the Pedro Cândido farm occurred due to the greater amount of branches, but this did not result in a better supply of nutrients. After 27 years of interventions, there was no influence of silvicultural systems on the fractions and amount of nutrients.

The investigation was carried out in the holm oaks in the Slate Altitude in the Agroforestry La Palma and in the Agroforestry Experimental Station of Viñales Municipality, with the objective to determine the structure and composition of natural oaks. Two different places were layed out regarding a level of man intervention. There were established 10 square plots (100 m2), five in each of the included in the areas in the study, in way simple aleatoia. Alpha and beta diversity was determined; the horizontal structure was evaluated by calculating the index of ecological importance and the distribution by diameter classes. Also, it was described the vertical structure through the richness of species in each stratum as well as its sociological position. The richness of the species proved a high floristic diversity associated to the oaks. There were identified 38 species associated to the oaks, grouped in 25 families, where the Melastomataceae family with four species and Fabaceae, Rubiaceae and Sapindaceae with three species is the most represented. It was proved that the silvicola management and pastoral of the pig livestock level had strong influence in the structure and composition of the natural oaks. It was determined that the Quercus cubano A. Rich.  As dominant specie with the most ecological importance in this formation, it has irregular presence in the structure of this forest, turning to be vulnerable to natural disturbances potential human intervention, showing a weak competitive skill. The obtained results constitute a reference for the management of this endemic specie in the west of Cuba.

“Jacaranda” (Jacaranda mimosifolia) and "mezquite” (Prosopis laevigata) are timber species that generally present problems with regard to the germination of their seeds in natural conditions, since they have a very hard and impermeable cover. Different treatments have been applied to improve the germinative response of both species with unfavorable results. This study aimed to know the effect of the pre-sowing laser biostimulation on germination and seedlings growth of these species. The seeds were biostimulated with a He-Ne laser (632 nm, 10 mW). Considering three replications of 50 seeds for each species, five irradiation treatments were applied (30 s, 60 s, 90 s, 120 s, 150 s) and control. The results for mezquite demonstrated that the highest number of germinated seeds (96%) was obtained with the treatments 90 s and 150 s; in contrast, the control seeds showed a lower germination percentage (16%). Additionally, the 30 s treatment produced a positive effect on the growth of the root, and it was different (p < 0.05) to the remaining treatments and the control. For Jacaranda, there were significant statistical differences (p < 0.05) between the control and the different treatments. 29% of seed germination occurs without any treatment. However, for 90 s and 120 s, germination is induced in a relatively high percent (97%-99%). For both species, the best treatment was 120 s, since higher values were recorded for all the morphological variables. It is concluded that laser biostimulation can produce beneficial effects on the germination of seeds and seedling growth and it could contribute to the propagation and conservation of these species.