Search Results (4)

The tropical dry regions in the Neotropics are under intense anthropogenic pressures, resulting in changes for local communities related with their life patterns, wellbeing, and their relationship with ecosystems. The region has a history of human occupation that has shaped the traditional use of resources. We evaluated the richness, redundancy, and divergence of traditional uses of tree species present in vegetation patches of the tropical dry region of the Gulf of Mexico using functional diversity indices. The most used species are Acacia cochliacantha, Cedrela odorata, Enterolobium cyclocarpum, Gliricidia sepium, and Guazuma ulmifolia, and the uses with the broadest distributions across the region are firewood and pasture management, while reforestation is the least common use. While distance to the nearest patch of the closest human settlement is the most predictive variable associated with inhabitants’ different uses or recognitions of the value of different plant species, the most recognized and valued species are widely distributed in Mexico. Even when the forest cover is greatly reduced, the inhabitants recognize numerous uses that can be obtained from the vegetation patches. The approach used in this work provides important baseline information, as well as a methodology that facilitates the identification of priority areas for conservation. Full article

Floods are amongst the most frequent and destructive type of disaster, causing significant damage to communities. Globally, there is an increasing trend in the damage caused by floods generated by several factors. Flooding is characterized by the overflow of water onto dry land. Tropical cyclones generate floods due to excess water in rivers and streams and storm surges; however, the hazard of both phenomena is presented separately. In this research we present a methodology for the estimation of flood hazards related to tropical cyclones, integrating runoff and storm surge floods. As a case study, we selected the south-western suburbs of the city of La Paz, the capital of the state of Baja California Sur in northwest Mexico. The city has experienced in recent years an expansion of the urban area. In addition, there is an infrastructure of great importance such as the transpeninsular highway that connects the capital with the north of the state, as well as the international airport. Our results indicate that urban areas, agricultural lands, as well as the air force base, airport, and portions of the transpeninsular highway are in hazardous flood areas, making necessary to reduce the exposure and vulnerability to these tropical cyclone-related events. A resulting map was effective in defining those areas that would be exposed to flooding in the face of the impact of tropical cyclones and considering climate change scenarios, which represents an invaluable source of information for society and decision-makers for comprehensive risk management and disaster prevention. Full article

Lianas are an important component of tropical forests, and may reach their highest densities in disturbed areas. However, information on seed and germination characteristics is scarce. Twenty Amazon liana species were screened for their germination characteristics, including light dependence, tolerance of desiccation and of alternating temperatures; these characteristics are considered important for the germination success in areas with relatively open canopies. Between 31–1,420 seeds per species were available, as 15 species seeds came from one mother plant. We studied seed biometry and conducted germination trials with fresh seeds (12 h light daily, or dark) and desiccated seeds at 25 °C. Germination at alternating temperatures (20/30 °C, 15/35 °C) was analyzed for nine species. Of the 20 species, eight species with the largest seeds had desiccation sensitive seeds; this is the first record for species of four genera and one family, where only desiccation tolerant seeds are otherwise recorded. Light-dependent germination was found in three species (0.01–0.015 g) and is the first record for two; however, results were based on seeds from one plant per species. Alternating temperatures of 15/35 °C decreased final germination of four out of nine species, and response to 20/30 °C cycles varied compared to constant 25 °C. Seed and germination characteristics of the species ranged from pioneer to climax traits indicating that establishment of lianas from seeds may be confined to species specific niches. Full article

High seed cost accompanied by poor germination and seedling performance renders cabbage nursery and field production enterprises unsustainable to many small-scale growers in tropical and sub-tropical countries. In most nurseries, adverse ecological conditions and pest damage are among the major factors responsible for poor seedling performance. The objective of this study was to test the potential use of eco-friendly net (EFN) covers as a low cost technology for sustainable cabbage seedling production. The study was a two-season experiment conducted using a randomized complete block design with five replications and two treatments. Treatments were: the standard open field transplant production (control) and transplant production under 0.4 mm mesh polyethylene net covering. EFN covering increased both temperature and relative humidity, enhanced seedling growth and reduced insect pest damage. Seed germination and seedling emergence were under the net covering earlier. Higher seed germination and seedling survival were recorded under the EFN treatment, indicating a potential for reducing the seed requirement per unit area of cabbage production. Seedlings grown under the nets had higher stomatal conductance and leaf chlorophyll content; furthermore, they grew taller, with more leaves within a shorter period of time compared to the control seedlings. The use of EFN in cabbage nurseries offers a sustainable technology for enhancing seedling performance by reducing pest infestation, thereby lowering production cost and improving the grower’s income. Full article