Communities In Semi-arid Region Research Articles

Can the traditional use of native plant species in rural communities in the Brazilian semi-arid region be affected by global warming?

Extreme climate change events are capable of modifying the physiognomy of landscapes, impacting millions of people around the world. Consequently, the traditional knowledge of people residing in these regions about local natural resources may also be affected. To identify how the traditional use of native plant species can be influenced by a change in the availability of these species in a rural community in a semi-arid region, in a scenario of climatic extremes, we developed a Pressure Indicator for Use Preference (PIUP), seeking to identify the species under the greatest pressure of use. The study was carried out in the São Francisco Rural Community, in the Cabaceiras Municipality, in the semi-arid region of the Paraíba State, with 42 local informants. The species with the highest PIUP had their potential distribution for the year 2050 modeled using the HadGEM2-ES climate model under the RCP4.5 scenario, as an optimistic forecast, and the RCP8.5 scenario, as a pessimistic forecast. The construction of the models identified a potential increase in the coverage area of ​​all analyzed species, with a greater territorial extension for the RCP8.5 scenario. Myracrodoun urundeuva, Mimosa tenuiflora and Croton blanchetianus were the species with the lowest potential area growth for the year 2050. The high use of species, especially M. urundeuva, associated with reduced growth in a more arid environment is a worrying factor for the population structure of the species, as well as for rural communities that make representative use of the species.

Integration of remote sensing in spatial ecology: assessing the interspecific interactions of two plant species in a semi-arid woodland using unmanned aerial vehicle (UAV) photogrammetric data.

The spatial structure of plant communities in semi-arid regions is mostly derived by plant-plant interactions and environmental heterogeneity. In this study, we investigated the intra- and interspecific interactions and their contribution to growth inhibition in the patches of Pistacia trees and Amygdalus shrubs in semi-arid woodland communities through the implementation of photogrammetric data provided by unmanned aerial vehicle (UAV). This study was conducted in a part of Wild Pistachio Natural Reserve covered by Pistacia-Amygdalus stands in Zagros Mountains, western Iran. We used univariate and bivariate forms of pair- and mark correlation functions and Analytical Global Envelopes under inhomogeneous Poisson process which allow detection of the interactions of the species within the 45-ha study area. Our results indicated that the UAV-derived photogrammetric data proved to be efficient in identification of the plant individuals (F-score ≈ 0.92 for both species). Additionally, strong coefficients of determination (R2 = 0.98 and 0.94 for Pistacia and Amygdalus, respectively) supported prediction of crown area. We observed the aggregation of the species individuals in clusters of conspecifics and heterospecifics at small spatial scales, most likely as a result of aggregation in favourable parts of the study area. The aggregation of the species within patches had a marked effect on their size (i.e., crown area, height) inferred as growth inhibition, probably due to intra- and interspecific competition. Our findings demonstrated that promising UAV photogrammetric data can be effectively utilized by ecologists for investigation of plant associations, hence increasing the potentiality of remote sensing in spatial ecology of vegetation patches in semi-arid environments.

Inequalities in water access patterns and limits of water citizenship in rural communities in the semi-arid region

Este artigo aborda três dimensões da problemática do acesso à água em comunidades rurais do semiárido brasileiro: a teórica, a pública e a distributiva. Argumenta-se que as principais perspectivas utilizadas para enquadrar o problema da água na região – seja a da crise hídrica global, da construção social do desastre da seca ou da convivência com o semiárido – representam diferentes versões de um “paradigma da oferta”, em que a insuficiência de água dá significado às situações sociais a serem enfrentadas. Analisa-se, então, os padrões de acesso à água potável para abastecimento humano que resultaram das ações executadas no âmbito de dois programas públicos destinados a aumentar a oferta de água nestas comunidades rurais por meio da construção de cisternas para aproveitamento de água de chuva e da implementação de sistemas de dessalinização de águas subterrâneas salinas ou salobras: o Programa de Formação e Mobilização Social para a Convivência com o Semiárido: um Milhão de Cisternas Rurais (P1MC) e o Programa Água Doce. Finalmente, defende-se uma perspectiva que enfatize questões distributivas, destacando desigualdades de diversas ordens e permitindo uma nova territorialização do problema do acesso à água no Nordeste, rompendo a separação entre rural e urbano para significar a problemática do acesso à água enquanto desigualdade estrutural, cotidianamente vivenciada, o que permite revelar conflitos ambientais latentes, a serem superados a partir da mobilização política em torno da noção de cidadania hídrica.

Distribution of small seasonal reservoirs in semi-arid regions and associated evaporative losses

To support the increasing demand of a growing population for freshwater, small-sized (<0.1 km2) water reservoirs are necessary in areas with limited infrastructure, especially in water-stressed regions having seasonal and variable precipitation. Seasonal storage in small reservoirs is often overlooked in present inventories. Accordingly, we assessed the current state in semi-arid regions using highly resolved Sentinel-2 satellite imagery. Globally, about 3 million small reservoirs are in operation in semi-arid regions having a total water surface area of 17 800 km2 and seasonal storage of 37 km3, supporting 15% of the world’s population in semi-arid regions. Estimated upper-bound of evaporative losses represent 38% (14 km3) of storage during dry season. The study estimates the evaporation suppression using floating covers and lays foundation to assess the feasibility of this technical solution to increase water savings. Significance and originality statement This study provides new insights into the distribution of seasonal freshwater storage in water stressed regions that support large rural population. We provide the first baseline dataset of this distributed freshwater resource to better assess the sustainability of communities in semi-arid regions with chronic water shortages. Water storage in semi-arid regions is subject to potential evaporative losses of nearly 40% of the stored water. We analyzed conditions where evaporative losses could be significantly reduced using floating covers, a simple and scalable solution suitable for regions with underdeveloped economies. The study as well ranks regions with highest potential benefits from evaporation suppression measures.

Effects of Medicago sativa-Triticale wittmack intercropping system on rhizosphere soil nutrients and bacterial community in semi-arid region of NorthwestChina

Semi-arid region of Northwest China is characterized by barren soil, with high pH and high carbonate content. Saline-alkali land is easily formed in this area, which inhibits soil microbial activity and results in soil nutrient loss. To improve soil health in this area, effects of intercropping alfalfa and triticale on rhizosphere soil nutrients and bacterial community structure were examined though a three-consecutive-year experiment. The results showed that soil organic matter (SOM) content of alfalfa rhizosphere in intercropping was significantly higher than that in monoculture, while pH and available potassium (AK) content were lower than that in monoculture. The concentrations of SOM, available nitrogen (AN), available phosphate (AP) and AK of triticale rhizosphere in intercropping were significantly higher than those in monoculture. The bacterial sequences, OTUs, richness, and diversity of alfalfa and triticale in rhizosphere soil were all higher than those in monoculture. At phylum level, Proteobacteria and Bacteroidetes were dominant, accounting for 31.1%-33.4% and 22.4%-32.2% of the total OTUs, respectively. The relative abundance of Bacteroidete was higher in intercropping than in monoculture. Actinomycetes in the monoculture were significantly higher. Acidobacteria in the intercropping triticale was significantly higher than that in monoculture triticale. Verrucomicrobia in intercropping alfalfa was significantly more abundant than that in monoculture of alfalfa. At genus level, Algoriphagus, Flavobacterium, Gp6, and Chryseolinea in monoculture were greater than those in intercropping, and Cellvibrio showed an opposite trend. Results of correlation analysis showed that the abundance of Proteobacteria and Bacteroidetes were negatively correlated with soil pH, while that of Bacteroidetes were positively correlated with SOM, TN and AN. However, the abundance of Chloroflexi, Planctomycetes, Acidobacteria, Verrucomicrobia, and Gemmatimonadetes was negatively correlated with SOM and AN. Overall, alfalfa-triticale intercropping is an effective strategy to improve soil health in semi-arid region of Northwest China.

Study on the accessibility of water sources to meet the water needs of rural communities in semi-arid regions of Indonesia

There are a large number of people in the world who live without an adequate supply of clean water, and spend hours to get clean water. For this reason, access to water and water sources is one of the main keys to meeting the needs of the community’s clean water, specifically rural communities in the semi-arid regions of Indonesia. This study aims to analyze the extent to which access to clean water sources affects the patterns of water use and fulfillment of rural communities. The method used is a survey completed with a questionnaire and observation. The object of the research was the rural water user community in TTS Regency, East Nusa Tenggara Province with a total of 87 families, and water sources in the study area. Samples were divided into three areas which were categorized as dry, normal and wet. based on the analysis of rainfall data at 14 rain stations. The results showed an average water use level of 49 Lpcd (SD = 25) and the distance to the water source as far as 521 m (SD = 1100). There is a negative correlation between the distance of the water source and the amount of clean water used. Water availability factors affect water usage more than long distances but can be reached. This study also found that the use of clean water by the community is adaptive to the availability of water according to environmental conditions. This study recommends the importance of handling clean water issues according to the characteristics of each different region.

Caracterização da qualidade da água subterrânea utilizando índices de qualidade da água em Riachão do Jacuípe, Bahia

A água subterrânea representa uma crucial fonte para abastecimento de comunidades rurais nas regiões semiáridas. A escassez hídrica, relatada em diversos estudos prévios, exige que sejam conhecidas e divulgadas informações sobre a qualidade da água disponível, como uma das formas para melhor gerir e conservar as reservas existentes. O principal objetivo deste trabalho foi caraterizar as águas de poços profundos na região de Riachão do Jacuípe (BA), por meio de Índices de Qualidade de Água (IQA), com a finalidade de dispor, aos moradores, gestores e tomadores de decisão, um recurso para informar, de maneira simples, a qualidade da água fornecida à comunidade. A pesquisa também investigou os usos e tratamento dispensados à água, com o intuito de sugerir medidas para corrigir possíveis carências. Para esses propósitos foram utilizados resultados de análises de água fornecidos pela Secretaria do Meio Ambiente (BA) e entrevistas junto à comunidade. Esta pesquisa é uma contribuição importante para compreender a relação entre a qualidade da água e a situação de vulnerabilidade das comunidades rurais do semiárido. Os objetivos foram alcançados com o uso de três metodologias de cálculo de índices de qualidade de água (IQA): IQA CETESB, CCME WQI e e-IQUAS, aplicadas para doze amostras de água, para as quais foram avaliados vinte parâmetros. Os resultados mostraram convergência na caracterização estabelecida nas três metodologias, todas as amostras foram classificadas como “ruins”. A aplicação de índices se mostrou adequada, todavia tais mecanismos devem ser associados a outros recursos de avaliação. Quanto ao senso dos usuários, os resultados sugerem que os moradores precisam conhecer melhor a relação entre a qualidade da água com possíveis riscos para a saúde. A disseminação dos Índices de qualidade de água pode ser um mecanismo eficaz, oportunizando a população, gestores e decisores determinarem ações para mitigar as carências percebidas.

Saving for a dry day: investigating well ownership and watering practices during droughts

ABSTRACTGrowing demands for irrigation water are tapping groundwater supplies beyond their natural rates of replenishment, which has profound implications for sustaining communities in semiarid regions. This paper investigates the drought-time watering practices of Kansas well owners, a key social group whose water consumption is pivotal to prolonging groundwater formations. I address two questions: Do well owners and non-well owners have different responses to droughts? Is the relationship between water supply awareness and water conservation during droughts moderated by water supply infrastructure? To answer these questions, I constructed one of the only datasets of well owners used in the social sciences by surveying well owners and non-well owners throughout Kansas (n = 864). My findings reveal that well ownership is significantly correlated to increased watering during droughts and water conservation varies among those who own different types of wells. Furthermore, increased levels of water literacy are negatively associated with water conservation during droughts. These findings support the Conservation of Resources theory, which holds that individuals stockpile their resources during non-stressful times and draw from their reserves during times of scarcity. Therefore, aquifer stewardship involves selective timing for making groundwater extractions.

Predictors of Arbuscular Mycorrhizal Fungal Communities in the Brazilian Tropical Dry Forest.

Arbuscular mycorrhizal fungi (AMF) are symbiotic fungi with a broad distribution, and many taxa have physiological and ecological adaptations to specific environments, including semiarid ecosystems. Our aim was to address regional distribution patterns of AMF communities in such semiarid environments based on spore morphological techniques. We assessed AMF spores at the bottom and top of inselbergs distributed throughout the tropical dry forest in the Northeast region of Brazil. Across 10 replicate inselbergs and the surrounding area, spanning a range of altitude between 140 and 2000m, we scored the AMF soil diversity and properties in 52 plots. We fitted parsimonious ordination analyses and variance partitioning models to determine the environmental factors which explained the variation in AMF community, based on morphological spore analysis. The diversity of AMF was similar at the bottom and top of inselbergs; however, we detected high variation in abundance and richness across sites. We formulated a parsimonious richness model that used physical soil factors as predictors. The AMF community structure could be best explained through the variables coarse and total sand, iron, organic matter, potassium, silt, and sodium which together accounted for 17.8% of total variance. Several AMF species were indicators of either deficiency or high values of specific soil properties. We demonstrated that habitat isolation of the inselbergs compared with surrounding areas did not trigger differences in AMF communities in semiarid regions of Brazil. At the regional scale, soil predictors across sites drove the distribution of symbiotic mycorrhizal fungi.

Avaliação físico-química das águas do processo de dessalinização de poços salobros e salinos em comunidades rurais do oeste potiguar

O fornecimento de água potável é o maior desafio das comunidades rurais da região semiárida do Brasil, que são caracterizadas pela escassez de recursos hídricos apropriados para consumo humano. Em uma tendência observada há alguns anos, os Governos Federal e Estadual têm buscado instalar equipamentos de dessalinização das águas salobras subterrâneas para a geração de água doce para o abastecimento de comunidades distantes dos centros urbanos. Desta forma, o objetivo deste trabalho foi avaliar a qualidade das águas oriundas do processo de dessalinização de poços em comunidades rurais do oeste potiguar e seus riscos quanto ao uso na irrigação. A pesquisa foi realizada no período de 2013 e 2014 e, inicialmente, foram identificadas as comunidades abastecidas com as unidades de captação e tratamento de água por dessalinização, através de um levantamento cadastral. Para isto, foram realizadas quatro campanhas de coletas em diferentes períodos do ano para avaliação da qualidade das águas potável do tratamento por osmose reversa, poço e rejeito salino, dentro de cada período. Foram analisados parâmetros físico-químicos das águas para fins de irrigação. As águas foram classificadas quanto ao uso na irrigação; aos riscos de problemas de infiltração no solo causados pela sodicidade da água e toxicidade em plantas. As estações de tratamento de água por osmose reversa nas comunidades rurais monitoradas produziram uma água dessalinizada com concentrações baixas de sais, com 68% do total das amostras na classe de classificação C1S1; 25% na classe C2S1 e; apenas 7% na classe C3S1. Com relação ao rejeito gerado, 93% das amostras de água de rejeito se classificaram como C3 ou C4 nos quatro períodos de coleta, ou seja, águas de alto ou extremamente alto risco de salinização.

Periphytic algae dynamics in lentic ecosystems in the Brazilian semiarid.

The hydrological periods drive the structure and organization of aquatic communities in semiarid regions. We hypothesize that a decrease of the precipitation during the dry period will favor the development of the periphytic algal community, leading to higher richness and density in this period. To test this hypothesis, we investigated the changes in the periphytic algal community structure in three shallow and eutrophic ecosystems of the Brazilian semiarid. The sampling was performed between 2007 and 2010 at two-mensal intervals. The sampling of periphytic algal was performed in aquatic macrophytes and rocks. The abiotic variables were analyzed simultaneously. Dominance in diatoms, cyanobacteria and chlorophytes, respectively, was observed in two periods. In the dry period, waters were alkaline and had high concentrations of nitrate and total phosphorus associated with the highest densities of Bacillariophyceae. In the rainy period the water was warmer, oxygenated and high concentrations of ammonia and soluble reactive phosphorus with diatoms remained dominant but with reduced density, while cyanobacteria and chlorophytes increased. Overall, periphytic algal community composition no responded to changes in the hydrological periods. However, the hydrological periods altered the dynamics of periphytic algal community, supported by the alternation of the most representative classes (diatoms and cyanobacteria) between the hydrologic periods. Our data suggest that the morphometric and chemical and physical characteristics of lentic aquatic ecosystems studied were more important in the dynamics of periphytic algal community than the hydrological periods and types of substrates.

Small scale gold mining effects on the miners and local communities in semi-arid region of Ethiopia

North Ethiopian highlands are traditionally known for gold mining which has been means of livelihood of the rural community. The present work was conducted to investigate socio-economic conditions of gold miners, ways of obtaining the gold, their earning and negative consequences of the gold mining. On the basis of random sampling, 140 miners were interviewed. Moreover, focus group discussions transect walks and practical observations across the mining sites were made with team leaders on different issues of gold mining and its effects. Descriptive statistics was used to compute socio-economic characteristics, gold harvesting, and income dynamics. ANOVA was run to observe variations of income from gold mining and other sources, 2009 to 2012. The positive effects of gold mining for involved people were regarding income, employment, expenditure on education, health and food consumption. On the other hand, conflicting interest, communicable diseases, aggressive child labour, school dropouts, social disruptions and injuries were challenges of the small scale gold mining. The findings highlight that the income generated from small scale gold mining plays a pivotal role in reducing rural poverty. Therefore, providing integrated training for gold miners can mitigate the challenges of small scale gold mining and thereby to improve livelihoods of the small scale gold miners in Ethiopia.

Means for retaining farming communities in semiarid regions of Gujarat state

Means for retaining farming communities in semiarid regions of Gujarat state

Riparian Seedling Mortality from Simulated Water Table Recession, and the Design of Sustainable Flow Regimes on Regulated Rivers

Seasonal water limitation exerts a strong ecological filter on stream communities in semiarid regions. For first‐year riparian willow and poplar tree seedlings, desiccation from rapidly declining river flows can limit reproduction, especially on rivers in which flow regulation and land conversion have limited the amount of area available for recruitment. We investigated survivorship of first‐year riparian seedlings to simulated river stage declines, focusing on the three dominant species in California's heavily regulated San Joaquin Basin: Fremont cottonwood, Goodding's black willow, and sandbar willow. Seedlings grown in mesocosms were subjected to water table decline rates typical in spring on unregulated and regulated rivers. We compared species' differences in survival time and fit the empirical data to accelerated failure time models that predicted time until death as a function of drawdown rate, initial seedling size, and maternal line. We used Akaike information criteria to select the best model for each species. Water table decline rates ≥ 6 cm/day were lethal to all species. At an intermediate rate (3 cm/day) survival varied most among species (12–38%) and was highest for Goodding's black willow. Failure time models indicated no maternal effects on survival but that initial seedling size was important for cottonwood. Using these models, we simulated survivable flow scenarios on the Tuolumne River (CA) and assessed the survivability of actual flow releases in two representative years. This modeling approach shows promise for optimizing flow releases to restore pioneer riparian habitat on regulated rivers in some of the world's most water‐limited regions.

Use patterns and knowledge of medicinal species among two rural communities in Brazil's semi-arid northeastern region

The present work seeks to quantify the knowledge of two rural communities in the semi-arid region of the state of Pernambuco (northeastern Brazil) concerning two species of native medicinal plants: “aroeira do sertão”, Myracrodruon urundeuva (Engl.) Fr. All. (Anacardiaceae) and “angico”, Anadenanthera colubrina (Vell.) Brenan (Mimosaceae). Semi-structured interviews were carried out, combined with a checklist/inventory method, which yielded different indexes for quantifying knowledge and use of these species. In addition, the reliability of local knowledge was tested using analytical techniques to determine actual tannin concentrations. Although both communities possess knowledge concerning these two species, one of them stood out in terms of the diversity of information presented ( P < 0.05), a difference that may be related to its lower degree of modernization. In general, older people had a greater variety of information about these plants, although both men and women demonstrated similar knowledge. Of the 101 people interviewed in Riachão, 85% stated that they knew of uses for both species studied; in Ameixas, of the 55 interviewees, 63% responded that they knew of uses for Myracrodruon urundeuva, and 45% knew of uses for Anadenanthera colubrina. A total of 97 different uses were reported by all informants for the two species studied. Of these, 62 were mentioned in only a single community, confirming our hypothesis of differences in knowledge between them. Informants from both communities knew of a great variety of uses for these plants as well as a number of different collection techniques. We expected that knowledge about the two species would differ in relation to both gender and age, but this was only true for one of the communities. Greater concentrations of tannins were expected to be found consistently in the tree bark, but experimental data demonstrated that tannin concentrations can vary among plant parts during the year.