Semi-arid Northeast Research Articles

Analysis of isoscapes (δD, δ18O and tritium) in groundwater in the semiarid northeast region of Mexico

Analysis of isoscapes (δD, δ18O and tritium) in groundwater in the semiarid northeast region of Mexico

Geomorphological Heritage and Geotourism in a Granite Terrain of the Semi-Arid Northeast of Brazil: The Case of the Uruburetama Massif

Geomorphological Heritage and Geotourism in a Granite Terrain of the Semi-Arid Northeast of Brazil: The Case of the Uruburetama Massif

Everything's not lost: Caatinga areas under chronic disturbances still have well-preserved plant communities

The caatinga, a thorny deciduous shrub-arboreal vegetation predominant in the semiarid Northeast Brazil region, has faced chronic anthropogenic disturbance since the arrival of Europeans. Areas experiencing strong anthropogenic pressure and climatic vulnerability are often overlooked in floristic and phytosociological studies, leading to limited knowledge about their biological potential. Thus, our objective was to assess the current vegetation state in three severely degraded nuclei undergoing desertification in Ceará and determine, based on the analysis of plant diversity (richness) and structure, if there is potential for natural regeneration. We sampled 36 plots (3.24 ha), measuring trees and shrubs with a diameter at ground level (DGL) ≥ 3 cm. The vegetation was stratified into three degradation levels: open, intermediate, and closed. The open level, most impacted by human activities, exhibited reduced plant richness, density, biomass, and height compared to other levels. In contrast, the intermediate and closed covers, prevalent in the study area, showed no significant differences from each other or from caatinga areas outside the desertification nuclei. We concluded that even severely degraded areas should possess high biological potential due to the presence of preserved remnants serving as reservoirs to maintain diversity and vegetation structure in the region.

It's not all about drought: What “drought impacts” monitoring can reveal

Drought impacts monitoring has been called the missing piece in drought assessment. The potential to improve drought management is high but uncertain due to rare analyses of impacts datasets, predominantly because there are few impacts monitoring programmes to generate the datasets. Drought impacts monitoring is conducted on the ground in much of Brazil by local observers at monthly and municipality scale to support the Brazilian Drought Monitor. In Ceará state, within drought-prone semiarid northeast Brazil, over 3600 drought impacts reports were completed by agricultural extension officers from 2019 to 2022. We investigated, through manual coding and observer interviews, the reported drought impacts and impact drivers. Analysis provided a catalogue of the experienced impacts and showed that impacts still occur, and are often normalised, during non-drought periods, sometimes as lingering effects of previous droughts. The impact drivers were predominantly non-extreme hydrometeorological conditions or a result of socio-technical vulnerabilities such as insufficient water infrastructure. The normalisation of “impacts” included, in particular: a generally accepted high level of crop losses and consistently low reservoir levels around which the agricultural and domestic systems are adapted. Conventional drought indices often did not align with experienced impact severity, highlighting the limitations of relying solely on these indices for emergency response. Continual impacts monitoring could be extremely valuable anywhere in the world for identifying vulnerabilities and informing proactive measures to reduce drought and other hazard risk, in addition to guiding targeted mitigation efforts.

Analysis of the seasonality of rain in Brazil from 1990 to 2022

Water resources are subject to hydroclimatic and spatio-temporal variations. This article aimed to analyze the seasonality of rainfall in Brazil. Precipitation data from 1306 rain gauge stations with data from 1990 to 2022. The precipitation seasonality index (PSI) was determined to evaluate the spatial and temporal variation in seasonality. The spatialization of ISP values ​​was carried out using the geostatistical method of ordinary kriging. The ISP values ​​found throughout the Brazilian territory vary from 0.273 to 1.176. This indicates that Brazil has humid regions with precipitation well distributed throughout the months throughout the year, to arid regions, with few months with rain. The lowest seasonal variability was found in the three states in the South region, on the coast of the states in the Southeast region and in the North region near the Amazon forest. The greatest seasonal variability occurs markedly in the Northeast region, close to the semi-arid Northeast, with long periods of drought

Intoxicações por anti-helmínticos em pequenos ruminantes diagnosticadas no Nordeste do Brasil

ABSTRACT: The clinical, epidemiological and anatomopathological findings of anthelmintic poisoning in small ruminants diagnosed at the Veterinary Hospital of the Federal University of Campina Grande, Patos, Paraíba, from January 2000 to December 2022 are described. A total of 1,928 necropsies were carried out on small ruminants, of which 1,032 were goats and 896 sheep. Four outbreaks of anthelmintic poisoning were identified in these species: one outbreak of ivermectin in sheep, one outbreak of disophenol in goats and sheep and two outbreaks of nitroxinil in goats. These intoxications accounted for 0.78% and 0.23% of goat and sheep diseases diagnosed routinely. In the case of ivermectin poisoning, the animal had neurological clinical signs, and no macroscopic or histopathological alterations were observed. In the outbreaks of disophenol and nitroxinil, the animals showed anorexia, hyperthermia, tachycardia, tremors, dyspnea, incoordination and limb rigidity. Macroscopically, there were liver and kidney lesions associated with circulatory alterations, such as hemorrhages and edema. Microscopically, necrosis and degeneration of hepatocytes and tubular epithelial cells associated with hemorrhage and congestion were observed. The prevalence of these intoxications in small ruminants is considered low in the Semi-arid Northeast, but outbreaks can occur with high lethality in herds. The main risk factor for the occurrence of intoxications was overdose, combined with other factors such as the age of the animals, high environmental temperature, constant exercise and low body score, which increased the toxicity of anthelmintics.

Drought-impacted communities in social-ecological systems: Exploration of different system states in Northeast Brazil

This study applies ‘Social-Ecological Systems (SES)’ concepts with the aim of analysing why and how events happening across spatial, jurisdictional, and temporal scales influence droughts and their impacts in rural communities. To trace the evolution of droughts and their impacts on the livelihood system, we conducted a drought diagnosis in the rural community of Riacho da Cruz in the Banabuiú basin in the semi-arid Northeast of Brazil. We analysed how the livelihood of this community reacted differently to drought events and why the impacts of previous drought events either contributed to the adaptation of the livelihood system or its collapse. SES theory helped us posit that it is the collective capacity of stakeholders (nested across the levels of the different spatial, temporal and decisional scales of drought management) to manage their resilience to drought, that determines whether the considered system adapts, collapses or shifts into a new stable state, in response to drought. Monitoring these factors that influence drought resilience could enable the development of drought(-impact) indices that account for the spatial-temporal complexities of drought. Such results can aid in improving the targeting of policies toward drought-affected communities and ensuring they receive the necessary resources. Plain language summaryDrought and drought impacts are difficult to monitor. One reason is that they affect many different areas and groups of people. It is complicated to understand all the ways in which droughts can worsen or how they impact different groups, and why these effects can change over time and in different locations. This is what we investigate in this study using the Social-Ecological Systems (SES) theory. SES theory can help us understand how different parts of society and the environment interact and change over time. This theory can help us understand why certain events happen and how past events can still have an impact on current events. We applied SES theory to the drought-affected rural community of Riacho da Cruz in Northeast Brazil to understand why and how different drought events affected the community’s livelihood. Based on our findings, we developed a framework that can help identify some causes of drought impacts on the community’s livelihood. We believe that this framework can also be applied to identify and understand the causes of drought impacts in different sectors and locations. Building on the case of the community of Riacho da Cruz, we discuss how the SES theory can help monitor drought more accurately.

Water quality from artesian wells in the northeastern semi-arid region: A literature review

Water from artesian wells usually has high levels of salinity, a factor in which potability standards must be analyzed in order to ascertain whether it is suitable for human consumption and other activities. The objective of this work was to present studies carried out on the analysis of the quality of water acquired through artesian wells in the northeastern semi-arid region, noting the possibility of using them in adequate conditions for human consumption. Data were collected through a literature review of research already carried out in this area that found results on the physical-chemical and microbiological aspects of water samples in different artesian wells located in different points of the northeastern semi-arid region. Based on the studies carried out, it is clear that in most of the water resources coming from artesian wells in the semi-arid northeast, it is necessary that the appropriate treatment be made for its use, thus making water within the required potability standards. It is concluded that, in view of the results obtained, the water obtained through artesian wells needs treatment before being destined for human consumption.

Physical-geographical characterization of the sedimentary plateau of Ibiapaba-Ceará and its morphsculpture

Belonging to the group of exception areas in the middle of the semi-arid northeast, important geomorphological features for the state of Ceará and for the Northeast region of Brazil, Ibiapaba presents forms of lush and particular landscapes. The Sedimentary Plateau of Ibiapaba represents a geomorphological compartmentalization of great expressiveness in northeastern Brazil, with an extension of approximately 380 km in the western part of Ceará. This work aims to present the physical aspects of the area through the physical-geographical characterization of these elements and their reflexes and their interaction with the morphosculpture of Ibiapaba in its northern part based on Ross's methodology (1992) for classification and systemic perspective as a subsidy. The materials and methods are constituted by the stage of bibliographic review, cartographic preparation, fieldwork and analysis of data and information. The results present the physical-geographic picture (geological, pedological, geomorphological, morphostructural and climatic aspects of the area and its interactions). Associated with the proposed objective, the physical-geographical framework of the area and morphostructure characteristics, it is understood that this level of approach may be essential to understand the geomorphological particularities of the region, as well as present in itself as a contribution to scientific studies in the area, serving as the basis for future studies.

Late quaternary geomorphological evolutionary dynamics of the Araripe sedimentary plateau, northeast of Brazil

The stratigraphic and geochronological data, compared to the set of ages already known for the semi-arid Northeast of Brazil, allowed us to understand part of the geomorphological dynamics of the sub-humid sector of the Araripe Plateau, in the south of the State of Ceará. Paleoenvironmental records were recovered through the study of Quaternary deposits generated by climatic inputs, in the range of 72.0 ka BP to the Early Holocene. Except for section CSM-C, it was observed that all other debris flows found do not exceed the MIS 3/LMG in age, and that morphogenetic events linked to gravitational flows are constrained until the Lower Holocene, coinciding with the findings in other sectors of the Northeast of Brazil such as the Borborema Highlands. Thus, as in other locations, it appears that the depositional processes and the formation of successive colluvial ramps in the Araripe Plateau occurred at times of strong climatic instability, as periods of intense rainfall disrupted the pedo-geomorphic equilibirum of the landscape. Despite the undeniable predominance of semi-arid conditions for the Brazilian Northeast during the Quaternary, the results obtained suggest that such conditions were neither homogeneous nor constant, and that in the last 40.0 ka. BP the Northeast experienced climatic fluctuations with abrupt oscillations, on millennial scales, from dry to wetter conditions and vice versa, which apparently coincide with the displacement of the ITCZ to more southern positions in line with the Heinrich events in the Northern Hemisphere. From the end of the Lower Holocene towards the Present, drainage began to actively dissect colluvial sediments, in response to continued changes in the base level around the Plateau. This scenario led to a longitudinal reworking of the sediments along valley bottoms and channels, forming fluvial plains. This aspect points to the fact that the surface dynamics of the landscape, at least from the Middle Holocene onwards, was rather defined by changes in the base level (and ultimately in land use), and erosion of colluvial deposits, than by the entry of new episodes of climatically conditioned sedimentation of great magnitude.

THE CONSTRUCTION OF THE HISTORY OF GEOGRAPHICAL THOUGHT IN/OF THE BRAZILIAN SEMIARID: A PROEMIC CONCEPTUAL DISCUSSION

The construction of the History of Geographic Thought (HPGeo) of the Semi-arid Northeast is a necessary and important study for understanding its consolidation in the scientific and (inter)national aspects. The objective is to analyze the construction of the History of Geographic Thought of the Semiarid Northeast of Brazil. The methodology is based on bibliographic research, seeking the theoretical-methodological support of the theme investigated and enabling the analytical interpretation of historical studies of geography and its scores with regard to the philosophical condition of the Brazilian Semiarid. The results are that its occupation, exploration and domain was based on hegemonic geographical perspectives, according to its historical epoch in chronological course at its level: (inter)national. Another important result was that the main predominant concepts were: geographic determinism, rationalism-systematic and mercantile-commercial capitalism at the Northeast level. Under the analysis in the regional section in the semi-arid region, two primary aspects were analyzed: the Conceptual and the Institutional one. The first focused on three relevant conceptual perspectives: Man, Nature and Economics (N-H-E). The second focused on the institutional, due to the systematic (organized) framework and the framework as a collective: the Farm, the Catholic Church and the Patriarchal Family. With this, geography is founded not only on resisting, but also existing, of transforming determinants into certain and possibilities in the feasibility of building, in today, the future in/your belonging to tomorrow.

The reterritorialization and the struggle for water of those affected by the transfer of the São Francisco River in the Brazilian Northeast

The implementation of the largest Brazilian hydrological project, theProjeto de Integração do rio São Francisco –PISF (water resources project implemented by the federal government in the Brazilian Northeast), responsible for transfering the river's waters into the semi-arid Northeast region of Brazil, had different effects in the region and caused the deterritorialization of several families. A portion of these families were reterritorialized into the 18 rural villages scattered throughout the project, where approximately 845 families were resettled. In this context, the research conducted in the rural village of Lafayette, in Monteiro/PB, aims to analyze the process of reterritorialization of the affected actors and their strategies to fight for access to water. For this purpose, we adopted a qualitative approach and ethnographic research, using procedures such as oral history interviews with actors resettled in the village, semi-structured interviews with institutional actors, in addition to collecting documents, photographs and observations recorded in the field diary. The results demonstrate the difficulties faced by families in the process of reterritorialization in the village, the emergence of conflicts over water, in addition to apprehending the different strategies of struggle of the affected actors to obtain access to water for human consumption. In this way, the study contributes to the problematization regarding those affected by the project and the access to water within such a large project whose motto is the distribution of water, though the lives of the affected families remain barren.

Response of vegetation to hydroclimate changes in northeast Brazil over the last 130 kyrs

In this paper, we use palynology and geochemical proxies to reconstruct late Quaternary vegetation changes within the hydrographic basin of Parnaíba, Northeast Brazil, over the last 130 kyrs. Findings are based on the analysis of a marine sediment core (GL-1248) retrieved from the western equatorial Atlantic (0°55.2′S, 43°24.1′W), close to the coast. Geochemical proxies (Fe/K ratio and ƐNd) indicative of soil erosion match changes in reconstructed vegetation, suggesting a dynamic pattern of hydrological disturbances and ecosystem evolution. Given that reconstructed vegetation does not present the same response to precipitation anomalies on the millennial scale, we sought the main drivers of vegetation changes in the Parnaíba watershed. Results indicate that vegetation succession was primarily influenced by austral insolation from March to May, which triggered changes in the pioneer vegetation types. Our study improves the knowledge of tropical vegetation dynamics in an orbital framework, suggesting 23-kyr precessional cycles as the main driver of landscape evolution in Northeast (NE) Brazil. We also infer that such past climate change events may have been a key causal factor of the high biodiversity of the Neotropics, mediated through the biological exchange of the Amazon and Atlantic rainforest species via ecological forest corridors in the semi-arid Northeast Brazil.

How heterogeneous is the dengue transmission profile in Brazil? A study in six Brazilian states.

Dengue is a vector-borne disease present in most tropical countries, infecting an average of 50 to 100 million people per year. Socioeconomic, demographic, and environmental factors directly influence the transmission cycle of the dengue virus (DENV). In Brazil, these factors vary between regions producing different profiles of dengue transmission and challenging the epidemiological surveillance of the disease. In this article, we aimed at classifying the profiles of dengue transmission in 1,823 Brazilian municipalities, covering different climates, from 2010 to 2019. Time series data of dengue cases were obtained from six states: Ceará and Maranhão in the semiarid Northeast, Minas Gerais in the countryside, Espírito Santo and Rio de Janeiro in the tropical Atlantic coast, and Paraná in the subtropical region. To describe the time series, we proposed a set of epi-features of the magnitude and duration of the dengue epidemic cycles, totaling 13 indicators. Using these epi-features as inputs, a multivariate cluster algorithm was employed to classify the municipalities according to their dengue transmission profile. Municipalities were classified into four distinct dengue transmission profiles: persistent transmission (7.8%), epidemic (21.3%), episodic/epidemic (43.2%), and episodic transmission (27.6%). Different profiles were associated with the municipality’s population size and climate. Municipalities with higher incidence and larger populations tended to be classified as persistent transmission, suggesting the existence of critical community size. This association, however, varies depending on the state, indicating the importance of other factors. The proposed classification is useful for developing more specific and precise surveillance protocols for regions with different dengue transmission profiles, as well as more precise public policies for dengue prevention.

Soaking curve and physiological quality of red rice seeds under salt stress

Red rice stands out as a component of the diet of family farmers in the semi-arid Northeast. In this region, the accumulation of salts can occur on the soil surface causing saline stress to the plants. Studies related to salinity during the critical phases of plant development are recommended. Therefore, the objective was to evaluate the effect of salt stress on water uptake and germination of red rice seeds. The experimental design used was entirely randomized. The treatments were four levels of electrical conductivity of water: 1.0 dS/m, 2.0 dS/m, 3.0 dS/m and 4.0 dS/m. The following variables were evaluated: water absorption, humidity, germination percentage, germination speed index, and mean germination time. Salinity decreased the speed of water uptake and provided the lowest water accumulation required for germination of red rice seeds. Salinity increased the germination time of red rice seeds by improving germination performance.

Reservoir sediment characterisation by diffuse reflectance spectroscopy in a semiarid region to support sediment reuse for soil fertilization

PurposeSoil erosion by water yields sediment to surface reservoirs, reducing their storage capacities, changing their geometry, and degrading water quality. Sediment reuse, i.e., fertilization of agricultural soils with the nutrient-enriched sediment from reservoirs, has been proposed as a recovery strategy. However, the sediment needs to meet certain criteria. In this study, we characterize sediments from the densely dammed semiarid Northeast Brazil by VNIR-SWIR spectroscopy and assess the effect of spectral resolution and spatial scale on the accuracy of N, P, K, C, electrical conductivity, and clay prediction models.MethodsSediment was collected in 10 empty reservoirs, and physical and chemical laboratory analyses as well as spectral measurements were performed. The spectra, initially measured at 1 nm spectral resolution, were resampled to 5 and 10 nm, and samples were analysed for both high and low spectral resolution at three spatial scales, namely (1) reservoir, (2) catchment, and (3) regional scale.ResultsPartial least square regressions performed from good to very good in the prediction of clay and electrical conductivity from reservoir (< 40 km2) to regional (82,500 km2) scales. Models for C and N performed satisfactorily at the reservoir scale, but degraded to unsatisfactory at the other scales. Models for P and K were more unstable and performed from unsatisfactorily to satisfactorily at all scales. Coarsening spectral resolution by up to 10 nm only slightly degrades the models’ performance, indicating the potential of characterizing sediment from spectral data captured at lower resolutions, such as by hyperspectral satellite sensors.ConclusionBy reducing the costly and time-consuming laboratory analyses, the method helps to promote the sediment reuse as a practice of soil and water conservation.

AGROECOLOGICAL SYSTEMS OF PRODUCTION AND FOOD CONSUMPTION IN SÃO DOMINGOS, SOBRAL, CEARÁ

The consumption of healthy foods is essential for nutrition and quality of human life. Thus, family farming is responsible for the production of organic food, since the people who inhabit urban centers depend on this sustainable production. In addition, the spatial clipping of the research is situated on the backcountry surface, in the semi-arid northeast. The community of São Domingos, is located 25 km from the municipality of Sobral- Ceará. The aim of the study is to characterize the agroecological systems of consumption and production (PAIS and Mandala) and to present their multiple uses, and commercial flows in the sale of cultivated products. It is concluded that agroecological systems are a source of income that fosters the local economy and helps in the healthy diet of people who consume the cultivated fruits.

Minimum Rainfall Inter-Event Time to Separate Rainfall Events in a Low Latitude Semi-Arid Environment

Water scarcity in dry tropical regions is expected to intensify due to climate change. Characterization of rainfall events is needed for a better assessment of the associated hydrological processes, and the proposition of adaptation strategies. There is still no consensus on the most appropriate method to separate rainfall events from a continuous database, although the minimum inter-event time (MIET) is a commonly used criterion. Semi-arid regions of low latitudes hold a distinct rainfall pattern compared to their equivalent at higher latitudes; these seasonally dry tropical forests experience strong spatial–temporal variability with intense short-duration rainfall events, which, in association with high energy surplus and potential evaporation, leads to an atmospheric water deficit. In this study, we identified the most adequate MIET based on rainfall data continuously measured at 5-min intervals over the last decade (2009–2020) in the semi-arid northeast of Brazil. The rainfall events were grouped according to different MIETs: 15 min, 1 h, 2 h, 3 h, 6 h, 12 h, and 24 h to determine rainfall depth, duration and intensity at intervals of 5, 30, and 60 min, time between events, and respective temporal distribution, with and without single tip events. Including single tip events in the dataset affected the number of rainfall events and respective characteristics up to a MIET of 3 h. A MIET of 6 h is the most appropriate to characterize the rainfall distribution in this tropical semi-arid region. Three classes were defined based on rainfall depth, duration, and intensity: I-small events (77% below 40 mm and 32 mm/h), II-high intensity events (3% between 36 and 76 mm/h), III-longer events of higher depth (20%). This study is useful for understanding how the MIET relates to other ecohydrological processes and provides more precise information on the rainfall characteristics at the event scale.

Mesquite (Prosopis juliflora) grain flour: New ingredient with bioactive, nutritional and physical-chemical properties for food applications

Mesquite (Prosopis juliflora) is a pod found in the semiarid Northeast region of Brazil. It is widely used as livestock feed and its by-product (the grain) has potential for human food. Thus, this article aims was to obtain flour from mesquite grains under different drying temperatures (50, 60, and 70ºC) and classify them by their physical-chemical, microstructural, technological, antioxidant, bioactive, and pasting properties. Both the mesquite grain and the mesquite grain flour showed a high amount of proteins and low-fat content. Analyses on morphology and viscosity indicated the presence of starch. Among the temperatures studied, the flour dried at 60 ºC presented the best results for the capacity of water and oil absorption, antioxidant activities, and total phenolic compounds. Seventeen compounds were detected by chromatography, with kaempferol, catechin, and quinine being the most abundant. This confirms the potential of mesquite flour as a relevant source of proteins and phenolic compounds for food products.

Relative growth and reproductive biology of females of Macrobrachium amazonicum (Heller, 1862) (Decapoda: Caridea: Palaemonidae) in the semiarid Northeast Region, Brazil

Abstract We analyzed aspects related to the relative growth and reproduction of females of Macrobrachium amazonicum (Heller, 1862) in a population of the semiarid Northeast Region of Brazil. Carapace (CL) and total length (TL) ranged 5.57–17.61 mm (mean 10.96 ± 2.07 mm) and 28.96–80.63 mm (mean 52.14 ± 9.13 mm), respectively. Relative growth analysis showed that total length increased in a higher proportion than carapace region (positive allometry). This region also increased in a higher proportion regarding weight (negative allometry) due to energy cost in reproduction. Of the three criteria used to determine size at the onset of maturity (SOM), the smallest size observed was obtained by physiological SOM I (based on advanced vitellogenesis): 8.22 mm CL, followed by functional SOM II (8.83 mm CL, based on ovigerous females) and physiological SOM III (9.48 mm, based on CL50). SOM was influenced by the population’s phenotype, and SOM I and SOM II showed synchronicity. The estimated maximum fecundity was 2,805 eggs per female, with a mean value of 690 eggs. There was continuous reproduction and the dry season favored the percentage occurrence of ovigerous females (September-December 2016 and July-August 2017). The smaller lengths of the individuals, compared to other female populations, were due to the characteristics of the environment and the intrinsic traits of the studied population. The negative allometry for the length-weight relation and the continuous reproductive period with seasonal variation was similar as that recorded for other Brazilian localities. This suggests that these last characteristics are a pattern for this species, which shows a latitudinal variation only in the sizes reached. The fast maturation and continuous reproduction of M. amazonicum females make them a potential species for commercial exploitation.