5 research outputs found

    The Habitat Types of Freshwater Prawns (Palaemonidae: <em>Macrobrachium</em>) with Abbreviated Larval Development in Mesoamerica (Mexico, Guatemala and Belize)

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    The freshwater prawns of genus Macrobrachium with abbreviated larval development have been reported from a diversity of freshwater habitats (caves, springs and primary streams from so-long basins). Here we analysed 360 sites around the Mesoamerican region (Mexico, Guatemala and Belize). At each site, we measured temperature, salinity oxygen dissolved, pH, altitude and water flow velocity values. We documented the riparian vegetation and occurrence and abundance of Macrobrachium populations. All these values were analysed by multi-dimensional scaling and principal components analysis in order to identify key features of the environmental data that determine the habitat types and habitat diversity. The results show that there are Macrobrachium populations in 70 sites inhabiting two main habitats: Lotic and Lentic; and each one have fours subhabitat types. All are defined by altitude range and water velocity that involve the temperature and oxygen variables. In some specific areas, the karstic values on salinity and pH defined some groups. Within the lentic habitats, we identified the following subhabitats: (1) temperate streams, (2) neutral streams, (3) high dissolved oxygen, (4) multifactorial; and for lotic habitats, we identified: (5) water high carbonate, (6) moderate dissolved oxygen, (7) low dissolved oxygen, and (8) high altitude streams. All these subhabitats are located on the drainage basin to the Atlantic Sea, including places from 50 to 850 meters above sea levels and have specifically ranges from temperature, water velocity, pH and salinity for some cases. Also, the geological analysis from the basins where the Macrobrachium inhabit is located showed that the geological faults align with these habitat subdivisions. In this chapter, we discuss the environmental heterogeneity, morphological plasticity and their relationship to physiographic regions across the species ranges

    Tropical Subterranean Ecosystems in Mexico, Guatemala and Belize: A Review of Aquatic Biodiversity and Their Ecological Aspects

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    The subterranean ecosystems in tropical areas of Mexico, North of Guatemala & Belize are very abundant because the karstic soil that allow these formations are the main composition in the Yucatán Peninsula and several mountains systems in these countries; also, they have a strong relationship with tropical forest adjacent where the main energy into the caves have an alloctonous origin. In these three countries there are three different cave conditions: a) freshwater semi-dry caves, b) flooded freshwater systems and c) anchialine systems. Mainly crustaceans and freshwater fishes are the major representative group in the aquatic diversity in these systems because the anchialine members are restricted to Yucatán Peninsula and Islands adjacent. Around 5000 entries to subterranean world there are among these countries, where the Yucatan Peninsula is the area with major caves or cenotes in comparison with southern of Mexico, North of Guatemala and Belize. Into these systems are possible found crustaceans and fishes from different families. The objective of this paper is present a review of these systems according with each karstic areas and show the current map including the location of each systems; as well their subterranean aquatic biodiversity and, finally discuss the relationships among these different areas using their biological aquatic richness in consideration with ecological subterranean conditions

    Spatiotemporal distribution, trend, forecast, and influencing factors of transboundary and local air pollutants in Nagasaki Prefecture, Japan

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    Abstract The study of PM2.5 and NO2 has been emphasized in recent years due to their adverse effects on public health. To better understand these pollutants, many studies have researched the spatiotemporal distribution, trend, forecast, or influencing factors of these pollutants. However, rarely studies have combined these to generate a more holistic understanding that can be used to assess air pollution and implement more effective strategies. In this study, we analyze the spatiotemporal distribution, trend, forecast, and factors influencing PM2.5 and NO2 in Nagasaki Prefecture by using ordinary kriging, pearson's correlation, random forest, mann–kendall, auto-regressive integrated moving average and error trend and seasonal models. The results indicated that PM2.5, due to its long-range transport properties, has a more substantial spatiotemporal variation and affects larger areas in comparison to NO2, which is a local pollutant. Despite tri-national efforts, local regulations and legislation have been effective in reducing NO2 concentration but less effective in reducing PM2.5. This multi-method approach provides a holistic understanding of PM2.5 and NO2 pollution in Nagasaki prefecture, which can aid in implementing more effective pollution management strategies. It can also be implemented in other regions where studies have only focused on one of the aspects of air pollution and where a holistic understanding of air pollution is lacking

    Data from: Effects of reduced-impact selective logging on palm regeneration in Belize

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    To assess the impacts of a low-intensity selective timber harvest on a palm community in Belize, we mapped logging infrastructure (i.e., roads, log landings, skid trails, and stumps) and measured palm regeneration 1 year after a timber harvest carried out using reduced-impact logging (RIL) practices. We sampled palms across a gradient of increasing harvest impact severity from areas not directly affected by logging, in felling gaps, on secondary and primary skid trails, and on log landings. We used generalised linear mixed-effect models fitted in a Bayesian framework and applied a non-metric multi-dimensional scaling of the ecological distances between sites to evaluate differences in palm seedling regeneration density and species composition, respectively. The harvest of an average of 2.5 trees ha−1 caused 0.4% of the forest to be converted to log landings, 0.7% and 3.6% to roads and skid trails, and 2.3% to felling gaps, which left 93.0% of the 350 ha harvest block with no direct impacts of logging. The difference in abundance and species composition of palm regeneration in unlogged areas compared to felling gaps and skid trails was small, but log landings had markedly lower densities. These results highlight that the impacts of selective logging are minor at least where harvest intensities are low and RIL practices are employed. If further reductions in canopy opening and soil disturbance are desired, we recommend that logs be cable-yarded (i.e., winched) the final 20 m to skid trails instead of driving to the tree stumps. We estimate that implementation of this practice would reduce total skid trail coverage from 3.6% to 2.9% and overall forest disturbance from 7.0% to 6.3%. However, further reductions in disturbance might be inimical to the maintenance of palms and will certainly not favour regeneration of light-demanding commercial timber species (e.g., Swietenia macrophylla)

    FEM_PALM_DATA

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    FEM_PALM_DATA: (1) The abundances (count data) for each palm species across disturbance categories and replicates (2 x 20 m plots). Also included are the abundances of non-palm woody stems for 1 m radius plots; and spherical densiometer readings at every 5 m interval along the central plot axis. (2) SPATIAL DATA: The spatial locations of plots in UTM coordinates (3) READ ME: Description of data contained in the spatial data and palm abundance data tables
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