Communities In Tropical Regions Research Articles

A geographic information system and analytic hierarchy process drought risk analysis approach in arid south-western Zimbabwe: Prospects for informed resilience building

Climate change is increasing the vulnerability of communities to drought, with rural communities in developing countries being affected the most. The study assessed drought vulnerability in south western Zimbabwe based on the Analytic Hierarchy Process (AHP) supported by Geographic Information System (GIS) and remote sensing techniques. An empirical research design based on verifiable evidence of drought vulnerability was adopted. GIS and remote sensing data were used to execute the multi-criteria AHP for the determination of drought vulnerability. ArcMap 10.8 software was used for the analysis of drought influencing factors and carrying out the weighted overlay. Results indicate that almost the whole of south western Zimbabwe is prone to droughts with only 0.6 % of the area being comparatively better. It was also noted that the majority of the population are exposed to high and extreme risk of droughts as they are settled in extreme and high drought risk zones. The study recommends implementation of resilience building interventions from an informed dimension where specific resilience building initiatives are implemented in appropriate environments for high returns. This can sustain the communities in the face of increasing drought risk due to climate change in line with the aspirations of the universal sustainable development goals and the country's vision of attaining an upper middle-income society by 2030. A framework for creating drought resilience was developed to ensure that development stakeholders cooperate to build drought resilient communities in tropical regions with drought challenges like Zimbabwe and the rest of Southern Africa.

Organometallics in Medicinal Chemistry: Antiparasitic Agents

Neglected tropical diseases (NTDs) encompass a diverse group of 20 medical conditions triggered by various pathogens, including viruses, bacteria, protozoa, and parasitic worms. Diseases caused by parasitic protozoa and parasitic worms show the highest incidence worldwide. NTDs predominantly afflict impoverished communities in tropical regions, although some exhibit a broader geographic reach. It is estimated that over 1 billion people suffer from NTDs, spanning 149 countries. Additionally, malaria is caused by protozoa of the genus Plasmodium and is highly prevalent in similar geographic regions. New drugs are urgently needed for the treatment of these diseases. In the last decades, various research groups have endeavored to develop organometallic compounds with potential applications as drugs against malaria and NTDs diseases caused by trypanosomatid parasites and parasitic helminths. This perspective highlights selected efforts from these groups in the pursuit of innovative therapeutic solutions. Relevant bioorganometallic compounds belonging to the typical classes of metallocenes, “half sandwich” M-arenes and metal carbonyls will be particularly described.

Multi-Environment Yield Components in Advanced Common Bean (Phaseolus vulgaris L.) × Tepary Bean (P. acutifolius A. Gray) Interspecific Lines for Heat and Drought Tolerance

Heat and drought are major stresses that significantly reduce seed yield of the common bean (Phaseolus vulgaris L.). In turn, this affects the profitability of the crop in climatic-vulnerable tropical arid regions, which happen to be the poorest and in most need of legume proteins. Therefore, it is imperative to broaden the sources of heat and drought resistance in the common bean by examining closely related species from warmer and drier environments (i.e., Tepary bean, P. acutifolius A. Gray), while harnessing such variation, typically polygenic, throughout advanced interspecific crossing schemes. As part of this study, interspecific congruity backcrosses for high temperature and drought tolerance conditions were characterized across four localities in coastal Colombia. Genotypes with high values of CO2 assimilation (>24 µmol CO2 m−2 s−1), promising yield scores (>19 g/plant), and high seed mineral content (Fe > 100 mg/kg) were identified at the warmest locality, Motilonia. At the driest locality, Caribia, one intercrossed genotype (i.e., 85) and the P. acutifolius G40001 control exhibited sufficient yield for commercial production (17.76 g/plant and 12.76 g/plant, respectively). Meanwhile, at southernmost Turipaná and Carmen de Bolívar localities, two clusters of genotypes exhibited high mean yield scores with 33.31 g/plant and 17.89 g/plant, respectively, and one genotype had an increased Fe content (109.7 mg/kg). Overall, a multi-environment AMMI analysis revealed that genotypes 13, 27, 82, and 84 were environmentally stable with higher yield scores compared to the Tepary control G40001. Ultimately, this study allows us to conclude that advanced common bean × Tepary bean interspecific congruity backcrosses are capable of pyramiding sufficient polygenic tolerance responses for the extreme weather conditions of coastal Colombia, which are likely to worsen due to climate change. Furthermore, some particular recombination events (i.e., genotype 68) show that there may be potential to couple breeding for heat and drought tolerance with Fe mineral biofortification, despite a prevalent trade-off, as a way to fight malnutrition of marginalized communities in tropical regions.

Prevalence and risk factors for chronic kidney disease of unknown cause in Malawi: a cross-sectional analysis in a rural and urban population

BackgroundAn epidemic of chronic kidney disease of unknown cause (CKDu) is occurring in rural communities in tropical regions of low-and middle-income countries in South America and India. Little information is available from Southern African countries which have similar climatic and occupational characteristics to CKDu-endemic countries. We investigated whether CKDu is prevalent in Malawi and identified its potential risk factors in this setting.MethodsWe conducted a cross-sectional study from January–August 2018 collecting bio samples and anthropometric data in two Malawian populations. The sample comprised adults > 18 years (n = 821) without diabetes, hypertension, and proteinuria. Estimates of glomerular filtration rate (eGFR) were calculated using the CKD-EPI equation. Linear and logistic regression models were applied with potential risk factors, to estimate risk of reduced eGFR.ResultsThe mean eGFR was 117.1 ± 16.0 ml/min per 1.73m2 and the mean participant age was 33.5 ± 12.7 years. The prevalence of eGFR< 60 was 0.2% (95% confidence interval (95% CI) 0.1, 0.9); the prevalence of eGFR< 90 was 5% (95% CI =3.2, 6.3). We observed a higher prevalence in the rural population (5% (3.6, 7.8)), versus urban (3% (1.4, 6.7)). Age and BMI were associated with reduced eGFR< 90 [Odds ratio (OR) (95%CI) =3.59 (2.58, 5.21) per ten-year increment]; [OR (95%CI) =2.01 (1.27, 3.43) per 5 kg/m2 increment] respectively. No increased risk of eGFR < 90 was observed for rural participants [OR (95%CI) =1.75 (0.50, 6.30)].ConclusionsReduced kidney function consistent with the definition of CKDu is not common in the areas of Malawi sampled, compared to that observed in other tropical or sub-tropical countries in Central America and South Asia. Reduced eGFR< 90 was related to age, BMI, and was more common in rural areas. These findings are important as they contradict some current hypothesis that CKDu is endemic across tropical and sub-tropical countries. This study has enabled standardized comparisons of impaired kidney function between and within tropical/subtropical regions of the world and will help form the basis for further etiological research, surveillance strategies, and the implementation and evaluation of interventions.

What does autonomy mean for forest communities? The politics of transnational community forestry networks in Mesoamerica and the Congo Basin

Since the 1990s, forest-dependent communities in tropical regions have created national and transnational grassroots networks. While in Latin America, their main goal is to promote community forestry and claim territorial rights, forest-dependent communities in the Congo Basin are more focused on improving participatory inclusion in forest policies. These diverging trends are rooted in the historical social movements’ struggles in Latin America and in the international actors’ push for more inclusion of local communities by governments in Central Africa. Given that the emergence of transnational community forestry networks is linked to different claims of autonomy based on regional context, how do the politics of autonomy driven by transnational grassroots networks influence community forest governance? This paper aims to examine how the different types of autonomy claimed by transnational grassroots networks, – vis-à-vis state bureaucracies, international partners and community organisations, – affect the multi-scale governance of community forestry in tropical regions. Our analysis draws on a political sociology and comparative politics approaches, through the case studies of the Mesoamerican Alliance of Peoples and Forests (AMPB) and the Network of Indigenous and Local Communities for the Sustainable Management of Forest Ecosystems in Central Africa (REPALEAC).

Seroepidemiology, modifiable risk factors and clinical symptoms of Toxocara spp. infection in northern Iran.

Toxocariasis is one of the most important and widespread neglected tropical infectious diseases. We designed a cross-sectional study to assess the seroepidemiological aspects of toxocariasis among the general population in northern Iran. A total of 630 rural subjects were enrolled to participate in the study. The presence of anti-Toxocara immunoglobulin G (IgG) was tested using a commercially available enzyme-linked immunosorbent assay. A structured questionnaire was also used to evaluate the potential risk factors and related clinical signs/symptoms. The presence of anti-Toxocara IgG antibodies was detected in 148 of the 630 rural subjects (23.5% [95% confidence interval {CI} 21.8 to 25.1]). By multivariate analysis, age (odds ratio [OR] 2.89 [95% CI 1 to -8.3], p=0.04), eating improperly washed vegetables (OR 4.05 [95% CI 2.47 to 6.64], p<0.001), contact with dogs (OR 3.31 [95% CI 2.13 to 5.12], p<0.001) and exposure to soil (OR 3.56 [95% CI 2.13 to 5.13], p<0.001) were significantly associated with the seroprevalence of Toxocara. The clinical study also demonstrated that the seroprevalence of Toxocara infection was significantly associated with asthma (OR 3.78 [95% CI 1.63 to 8.75], p<0.001) and ophthalmic disorder (OR 1.83 [95% CI 1.04 to 3.21], p=0.034). The findings proved that residents of rural communities in tropical regions may be heavily exposed to Toxocara spp. We highly recommend more investigations in high-risk groups.

Indigenous underutilized vegetables for food and nutritional security in an island ecosystem

Indigenous plants are an important component of the traditional food and health systems of rural and tribal communities in tropical regions. However, they do not attract much attention from researchers or in commercial markets. The present study investigated 42 indigenous, under-utilized vegetable plants from the Andaman and Nicobar Islands of India for their food and ecological values. Predominantly, the plants belonged in the Cucurbitaceae, Amaranthaceae, Moraceae and Plantaginaceae families. Fifty seven percent of the vegetables were observed in home gardens and 21.4% were collected from wild habitats. Most of the indigenous vegetables were perennials (71.4%), and included trees, vines and shrubs. Commercial farmers grew mostly exotic vegetables, while many indigenous and under-utilized vegetables were preferred by tribal and local communities. Herbs with good flavour, taste and crispness were preferred in culinary preparations; vegetables with a bitter taste and unique flavour were considered best for health purposes. The indigenous and under-utilized vegetables contained a wide range of nutrients, including Ca, Fe, polyphenols, carotenoids, ascorbic acid and chlorophyll, although they also often contained anti-nutrients including nitrate, phytate, oxalate and saponins. Our findings support the greater use of indigenous underutilized vegetables as promising and locally accepted options to address micronutrient deficiencies among households in geographically challenged regions such as the Andaman and Nicobar Islands. The study also underlined the need to devise strategies for the promotion of these nutrient-rich indigenous foods to improve the nutrition and livelihoods of vulnerable communities.

Dengue Serotype Differences in Urban and Semi-rural Communities in Ecuador

Dengue is a major vector-borne infection causing large outbreaks in urban communities in tropical regions. During the period 2010- 2014; 434 serum samples from febrile patients were collected from a semi-rural community hospital located in the norwestern region of Ecuador. Dengue virus (DENV) was investigated by reverse transcriptase PCR; a total of 48 samples were positive for dengue. During our study we detected DENV-2 and DENV-3 from 2010 to 2013 and the four DENV serotypes during the period 2013-2014. Surprisingly, our results contrasted with surveys carried out in urban centers throughout the Ecuadorian Coast in which DENV-1, DENV-2 and DENV-4 were prevalent during years 2010-2013 and only 2 serotypes (DENV-1 and DENV-2) in 2014.These results suggest that dengue viruses in semi-rural communities didn"™t originate in the Ecuadorian cities.

Long-term regeneration of a tropical plant community after sand mining.

Sandy coastal plant communities in tropical regions have been historically under strong anthropic pressure. In Brazil, these systems shelter communities with highly plastic plant species. However, the potential of these systems to regenerate without human assistance after disturbances has hardly been examined. We determined the natural regeneration of a coastal sandy plain vegetation (restinga) in Brazil, 16 years after the end of sand removal. We inventoried 38 plots: 20 within a sand‐mined site and 18 in an adjacent undisturbed site. We expected lower diversity values in the sand‐mined site compared to the undisturbed site, but similar species composition between the two sites due to the spatial proximity of the two sites and the high plasticity of restinga species. Species were ranked using abundance and importance value index in both sites, and comparisons were performed using Rényi entropy profiles, rarefaction curves, principal component analysis, and redundancy analysis. Species composition and dominant species differed markedly between the two sites. Bromeliads and Clusia hilariana, well‐known nurse plants, dominated the undisturbed site but were almost absent in the regenerating site. Species richness did not differ between both sites, but diversity was higher in the undisturbed site. Within‐site composition differences in the mined area were associated with field characteristics. Interestingly, species classified as subordinate or rare in the undisturbed site became dominants in the regenerating site. These newer dominants in the sand‐mined site are not those known as nurse plants in other restingas, thus yielding strong implications for restoration.

A Synthesis of the Available Evidence to Guide the Design of Mixed-Species Forest Plantings for Smallholder and Community Forestry

There is growing interest in using multi-species plantation systems when undertaking reforestation for timber production. Such plantations can have ecological and socio-economic advantages over those of traditional monocultures. Despite increasing evidence about the functional advantages of increasing species richness in reforestation, there are few silvicultural guidelines to assist in the design and management of multi-species plantings. This paper presents the results of a systematic assessment of previous studies of mixed-species plantings with a particular focus on their advantages and disadvantages for meeting the needs of rural smallholders and communities in tropical regions. Research on mixed-species plantations has increased in recent years. Many earlier studies were concerned with the capacity of mixed-species plantings to improve productivity or the nutritional impacts of mixtures. Many of these studies emphasised young plantations and mixtures of a few relatively fast-growing Acacia, Eucalyptus and Pinus species. More recent studies have explored a wider range of outcomes arising from using mixtures including on the supply of ecosystem services. Issues deserving further study concern the economic advantages or disadvantages of mixed-species plantations, how these plantations might be designed to suit various environmental and socio-economic situations, and how to manage older mixed-species plantations where the interactions between species may be different to those in younger plantations. There is also a need to explore how increased species richness may affect the capacity of new plantations to withstand damage from insect pests or disturbances such as storms or wildfire.

A retrospective study and predictive modelling of Newcastle Disease trends among rural poultry of eastern Zambia

Newcastle Disease (ND) is a highly infectious disease of poultry that seriously impacts on food security and livelihoods of livestock farmers and communities in tropical regions of the world. ND is a constant problem in the eastern province of Zambia which has more than 740 000 rural poultry. Very few studies give a situational analysis of the disease that can be used for disease control planning in the region. With this background in mind, a retrospective epidemiological study was conducted using Newcastle Disease data submitted to the eastern province headquarters for the period from 1989 to 2014. The study found that Newcastle Disease cases in eastern Zambia followed a seasonal and cyclic pattern with peaks in the hot dry season (Overall Seasonal Index 1.1) as well as cycles every three years with an estimated provincial incidence range of 0.16 to 1.7% per year. Annual trends were compared with major intervention policies implemented by the Zambian government, which often received donor support from the international community during the study period. Aid delivered through government programmes appeared to have no major impact on ND trends between 1989 and 2014 and reasons for this are discussed. There were apparent spatial shifts in districts with outbreaks over time which could be as a result of veterinary interventions chasing outbreaks rather than implementing uniform control. Data was also fitted to a predictive time series model for ND which could be used to plan for future ND control. Time series modelling showed an increasing trend in ND annual incidence over 25 years if existing interventions continue. A different approach to controlling the disease is needed if this trend is to be halted. Conversely, the positive trend may be a function of improved reporting by farmers as a result of more awareness of the disease.

DNA-metabarcoding uncovers the diversity of soil-inhabiting fungi in the tropical island of Puerto Rico

Soil fungal communities in tropical regions remain poorly understood. In order to increase the knowledge of diversity of soil-inhabiting fungi, we extracted total DNA from top-organic soil collected in seven localities dominated by four major ecosystems in the tropical island of Puerto Rico. In order to comprehensively characterize the fungal community, we PCR-amplified the internal transcribed spacer 2 (ITS2) fungal barcode using newly designed degenerated primers and varying annealing temperatures to minimize primer bias. Sequencing results, obtained using Ion Torrent technology, comprised a total of 566,613 sequences after quality filtering. These sequences were clustered into 4140 molecular operational taxonomic units (MOTUs) after removing low frequency sequences and rarefaction to account for differences in read depth between samples. Our results demonstrate that soil fungal communities in Puerto Rico are structured by ecosystem. Ascomycota, followed by Basidiomycota, dominates the diversity of fungi in soil. Amongst Ascomycota, the recently described soil-inhabiting class Archaeorhizomycetes was present in all localities, and taxa in Archaeorhizomycetes were among the most commonly observed MOTUs. The Basidiomycota community was dominated by soil decomposers and ectomycorrhizal fungi with a distribution strongly affected by local variation to a greater degree than Ascomycota.

Community structure of shallow rocky shore fish in a tropical bay of the southwestern Atlantic

Abstract Southwestern Atlantic Ocean rocky shores sustain important reef fish communities. However, those communities in tropical regions are not well understood, especially in Brazil. In this present article we assess community parameters of reef fishes such as composition, trophic organization and their relationships with physical and biological factors on four tropical rocky shores in Todos os Santos Bay, southwestern Atlantic. During six months, a total of 80 visual censuses were performed, in which 3,582 fish belonging to 76 species were recorded. Territorial herbivorous fish and turf algae were dominant at all the sites. The spatial variability of fish community structure was related to the benthic cover composition and depth. The high abundance of territorial herbivores and mobile invertebrate feeders could be associated with high levels of turf cover, low wave exposure and shallow waters. Moreover, this fact could be a consequence of the low density of roving herbivores and large carnivores probably due to the pressure of intense fishing activity. Thus complementary studies are needed to evaluate the actual conservation status of these rocky shore reefs, singularly located habitats connecting inner and outer reefs in Todos os Santos Bay.

Bycatch fauna of seabob shrimp trawl fisheries from Santa Catarina State, southern Brazil

Marine communities in tropical regions contain a great diversity of species that play key roles in ecological processes. The observed bycatch fauna in artisanal fishing for the seabob shrimp Xiphopenaeus kroyeri (Heller, 1862) in the southwest Atlantic exceeds the quantity of commercial shrimp captured. This bycatch has not been previously inventoried extensively in Brazil, particularly in the State of Santa Catarina, where small-scale shrimp fisheries is a traditional activity and dominates the local fishing economy. Six municipalities were sampled three times a month, from 1996 to 2011, yielding 216 species belonging to the bycatch (7 cnidarians, 22 mollusks, 42 crustaceans, 11 echinoderms, and 134 fishes). Bycatch management is a pressing aspect of shrimp fisheries. By inventorying the accidental bycatch, we provide a preliminary step towards defining intervention measures to reduce or make better use of this bycatch in seabob artisanal fisheries. Conservation of marine biodiversity is still inadequate in Brazil. We have attempted to identify additional threats to vulnerable and endangered species resulting from shrimp trawling.

Interaction between distant taxa in the use of tree cavities in African ecosystems: a study using nest-boxes

Abstract:Convergence in the use of resources may occur between distantly related organisms. A major ecological resource in which members of various taxa may be interested is a cavity for nesting. A variety of social hymenopterans and vertebrates may nest within tree cavities in tropical ecosystems. We used 241 nest-boxes placed in seven Kenyan localities to investigate the use of nesting cavities by members of distant taxa and discuss whether interaction between them is a potential factor shaping cavity-nester communities in tropical regions. The nest-boxes were occupied by social insects (ants, bees and wasps) (30.1% of nest-boxes in April–May and 33.1% in September–October) and vertebrates (birds and mammals) (20% and 7.7%, respectively). Hymenopterans were more abundant in forest boxes (36.2% of nest-boxes occupied in April–May and 37% in September–October), whereas savannas had lower figures (21.7% and 31.3%, respectively). Among vertebrates, most occupants of nest-boxes in savanna were birds (17.8% of nest-boxes occupied vs. 8% in mammals), while mammals predominated in forests (4.9% of the nest-boxes occupied vs. 0.3% in birds). Spatial and temporal patterns of occupation highlight the potential that interaction between distant taxa may have on the access to nesting cavities. More nest-boxes remained unoccupied in forested areas than in savanna areas suggesting that a shorter supply of nesting sites in the savanna may be a source of competition. The simultaneous occupation of a nest-box by two different taxa was exceptional, also supporting the hypothesized inter-taxon competition.

Diversity, Community Structure, and Niche Characteristics within a Diurnal Raptor Assemblage of Northwestern Peru

Abstract. Despite high raptor diversity and species of conservation importance, little is known about the structuring of raptor communities in tropical regions. We examined diversity across land uses, spatial-niche overlap among species, community structure, and relationships between abundance and niche position/width of diurnal raptors in Peru. Between April and December in 2008 and 2009, we surveyed raptors by distance sampling along transects, and recorded associated habitat data, in 70 randomly selected plots of 1 km2 in Cerros de Amotape National Park, the Tumbes National Reserve, and its buffer areas. We recorded 563 sightings of 19 species of diurnal raptors. Abundance and richness were highest in the buffer zone and lowest in the national park. Mantel tests revealed no correlation between the species' spatial-niche overlap and body-size differences, but there was a near-significant relationship between spatial-niche overlap and dietary overlap. A canonical correspondence analysis (CCA) of raptor s...

"AURORA TROPICAL": A PROPOSAL OF ECOLOGICAL AND URBAN HORTICULTURE, THE CASE OF ONE SECONDARY SCHOOL IN CABUDARE CITY OF VENEZUELA

ISHS XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Horticulture for Development AURORA TROPICAL: A PROPOSAL OF ECOLOGICAL AND URBAN HORTICULTURE, THE CASE OF ONE SECONDARY SCHOOL IN CABUDARE CITY OF VENEZUELA

Study of safety and effectiveness of traditional dosage forms of the seed of Aristolochia elegans Mast. against malaria and laboratory investigation of pharmaco-toxicological properties and chemical constituents of its crude extracts

Background: Local communities in tropical regions, mainly in Africa, have used traditional herbal medicines as means of preventing and treating malaria with unrealistic experimental analysis. Aims: The safety and effectiveness of traditional dosage forms of dried seed of Aristolochia elegans mast. Was therefore assessed on 20 respondents who had been using the seed of this medicinal plant for […]

Fate and effects of the insecticide chlorpyrifos in outdoor plankton‐dominated microcosms in Thailand

The fate and effects of the insecticide chlorpyrifos were studied in plankton-dominated, freshwater microcosms in Thailand. Disappearance rates of chlorpyrifos from the water column in the present study were similar to those in temperate regions. Insecticide accumulation in the sediment was relatively small, with the major part in the top layer (depth, 1.5 cm). Application of chlorpyrifos led to significant changes in freshwater biological communities. Clam shrimps (Conchostraca) and the cladoceran Moina micrura were the most susceptible species (no-observed-effect concentration [NOEC], 0.1 microg/L) and macroinvertebrates the most sensitive community (NOEC, 0.1 microg/L). These results are in agreement with those from semifield experiments with chlorpyrifos in temperate regions. The results of an in situ bioassay were used to calculate a NOEC of 0.1 microg/L and a 48-h median lethal concentration of 0.6 microg/L for M. micrura, which are similar to toxicity values reported for Daphnia magna in studies in temperate regions. Overall, these findings support the use of toxicity data from temperate regions for the risk assessment of low-persistent insecticides like chlorpyrifos for aquatic communities in tropical regions.

The role of indirect interactions in structuring tropical insect communities

Apparent competition is a form of indirect interaction among species that can potentially structure biological communities. In insect communities, parasitoid‐mediated apparent competition has been proposed as a particularly important structuring force. We argue that short‐term apparent competition may be less important in structuring insect communities in tropical regions, compared with temperate regions. This prediction arises because, compared with temperate insects, tropical insects that share natural enemies are more likely to be isolated in both space and time.