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1.
Ecol Evol ; 14(4): e11230, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38681185

ABSTRACT

Generally, species with broad niches also show large range sizes. We investigated the relationship between hydrological niche breadth and geographic range size for Amazonian tree species seeking to understand the role of habitat specialization to Amazonian wetlands and upland forests on the current distribution of tree species. We obtained 571,092 valid occurrence points from GBIF and SpeciesLink to estimate the range size and the niche breadth of 76% of all known Amazonian tree species (5150 tree species). Hydrological niche breadth was measured on different unidimensional axes defined by (1) total annual precipitation; (2) precipitation seasonality; (3) actual evapotranspiration; and (4) water table depth. Geographic range sizes were estimated using alpha-hull adjustments. General linear models were used to relate niche breadth to range size while contrasting tree species occurring and not occurring in wetlands. The hydrological niche breadth of Amazonian tree species varied mostly along the water table depth axis. The average range size for an Amazonian tree species was 751,000 km2 (median of 154,000 km2 and standard deviation of 1,550,000 km2). Niche breadth-range size relationships for Amazonian tree species were positive for all models, and the explanatory power of the models improved when including whether a species occurred in wetlands or in terrestrial uplands. Wetland species had steeper positive slopes for the niche breadth-range size relationship, and consistently larger range sizes for a given niche breadth. Amazonian tree species varied strongly in hydrological niche breadth and range size, but most species had narrow niche breadths and range sizes. Our results suggest that the South American riverscape may have been acting as a corridor for species dispersal in the Neotropical lowlands.

2.
Sci Total Environ ; 913: 169442, 2024 Feb 25.
Article in English | MEDLINE | ID: mdl-38157899

ABSTRACT

Patterned bog and fen peatlands of the Hudson Bay Lowlands, which form one of the largest continuous peatland complexes in the world, are globally significant stores of carbon and important water conveyance and storage features on the landscape. However, expansion of resource exploration and extraction combined with warmer temperatures associated with climate change may result in reduced water availability to these peatland complexes, potentially disrupting peatland hydrological connectivity and hydrogeochemical cycling. A case study on the effects of reduced water availability on peatland hydrological and geochemical function was conducted near the De Beers Victor Diamond Mine, located 90 km west of Attawapiskat. Active dewatering occurred here over a 12-year period (2007-2019) during which a 1.5 km transect was monitored within the mine impacted radius. Hydrological (streamflow and groundwater levels) and chemical (porewater and surface water samples) parameters were collected at the impacted transect and two nearby unimpacted reference sites. Results demonstrated that impacted peatlands had depleted water storage and spent an average of 50 % less time hydrologically connected than unimpacted peatlands. By the end of the study period, increasingly depleted water storage within the dewatering radius resulted in disproportionately lower flowrates in two tributaries downgradient of the mine-impacted peatlands when compared with the reference sites. Moreover, diminished water storage allowed solute-depleted precipitation to reach greater depths within the peat profile, while stronger downwards gradients suppressed upwards flow into fens, limiting the amount of solute-enriched water reaching the surface. The recovery of fen solute concentrations will be a prolonged process (i.e., decades to centuries) due to the slow rate of upwards diffusion, which may result in the transition of these systems towards ombrotrophic bogs. Further studies should focus on the susceptibility of these impacted systems to further reductions in water availability due to climate change.

3.
PhytoKeys ; 226: 89-100, 2023.
Article in English | MEDLINE | ID: mdl-37249925

ABSTRACT

Spiranthes Rich. (Orchidaceae) is a commonly encountered but systematically and nomenclaturally challenging component of the North American orchid flora. Here, the evolutionary history and hybrid origin of the recently described S.sheviakii Hough and Young are critically examined. The available molecular data unambiguously support a hybrid origin of S.cernua (L.) Rich. × S.ochroleuca (Rydb.) Rydb. for S.sheviakii, the same parentage as the priority name S.×kapnosperia M.C. Pace. As hybrid formulas can have only one correct name, S.sheviakii is a synonym of S.×kapnosperia. It is likely that S.×kapnosperia evolved independently at least twice in at least two widely disjunct locations.

4.
Elife ; 122023 04 18.
Article in English | MEDLINE | ID: mdl-37070964

ABSTRACT

Archaeological cobs from Paredones and Huaca Prieta (Peru) represent some of the oldest maize known to date, yet they present relevant phenotypic traits corresponding to domesticated maize. This contrasts with the earliest Mexican macro-specimens from Guila Naquitz and San Marcos, which are phenotypically intermediate for these traits, even though they date more recently in time. To gain insights into the origins of ancient Peruvian maize, we sequenced DNA from three Paredones specimens dating ~6700-5000 calibrated years before present (BP), conducting comparative analyses with two teosinte subspecies (Zea mays ssp. mexicana and parviglumis) and extant maize, that include highland and lowland landraces from Mesoamerica and South America. We show that Paredones maize originated from the same domestication event as Mexican maize and was domesticated by ~6700 BP, implying rapid dispersal followed by improvement. Paredones maize shows no relevant gene flow from mexicana, smaller than that observed in teosinte parviglumis. Thus, Paredones samples represent the only maize without confounding mexicana variation found to date. It also harbors significantly fewer alleles previously found to be adaptive to highlands, but not of alleles adaptive to lowlands, supporting a lowland migration route. Our overall results imply that Paredones maize originated in Mesoamerica, arrived in Peru without mexicana introgression through a rapid lowland migration route, and underwent improvements in both Mesoamerica and South America.


The plant we know today as maize or corn began its story 9,000 years ago in modern-day Mexico, when farmers of the Balsas River basin started to carefully breed its ancestor, the wild grass teosinte parviglumis. Recent discoveries suggest the crop may have started to travel to South America before its domestication was fully complete, leading to a complex history of semi-tamed lineages evolving in parallel in different regions. For example, 5,300-year-old corn specimens found in Tehuacán, in central Mexico, still genetically and morphologically resemble teosinte. Meanwhile, cobs harvested about 6,700 to 5,000 years ago on the northern coast of Peru ­ 3800km away from where maize was first domesticated ­ look like the ones we know today. Vallebueno-Estrada et al. aimed to explore the evolutionary history of this Peruvian maize, which was discovered at the archaeological coastal site of Paredones. To do so, they extracted and sequenced its genetic information, and compared these sequences with those from modern varieties of lowland and highland maize, as well as from teosinte parviglumis and teosinte mexicana. The analyses showed that the ancestor of the Paredones maize emerged from teosinte parviglumis like any other lineage, but that it was already domesticated when it started to spread South; by the time it was present in Peru 6,700 years ago, it was genetically closer to modern-day crops. This early departure is consistent with the fact that the Paredones specimens lacked teosinte mexicana genetic variants; this highland relative of lowland parviglumis is believed to have interbred with maize lineages from Central America more recently, when these were brought to higher altitudes. The presence of genetic marks tailored to low-elevation regions suggested that the Paredones maize lineage migrated through a coastal corridor connecting Central and South America, arriving in northern Peru about 2,500 years after first arising from teosinte parviglumis in Central America around 9,000 years ago. Under the care of rapidly developing Central Andean societies, the crop then evolved to adapt to its local conditions. Maize today has spread to all continents besides Antarctica; we produce more of it than wheat, rice or any other grain. How our modern varieties will adapt to the environmental constraints brought by climate change remains unclear. By peering into the history of maize, Vallebueno-Estrada et al. hope to find genetic variations which could inform new breeding strategies that improve the future of this crop.


Subject(s)
Domestication , Zea mays , Peru , Zea mays/genetics , South America , Mexico
5.
Environ Manage ; 72(4): 785-804, 2023 10.
Article in English | MEDLINE | ID: mdl-36914770

ABSTRACT

Pegged on Protection Motivation Theory, a modified socio-cognitive model of private adaptation to climate change and variability was deployed in order to provide a better understanding of the determinants of small-scale farmers' adaptation intent and adoption of adaptation strategies in semi-arid lowlands of Mwanga District. In this regard, adaptation was conceptualized as a two-step process encompassing farmers' perceptions that climate was changing and farmers' response to changes. Basing on a pragmatic philosophy, a cross-sectional sequential explanatory mixed methods research design was deployed. During the first step-process, categorical data were collected through administration of a closed-ended survey questionnaire to 328 household heads. Binary and proportional odds logistic regressions were run through IBM SPSS (Version 20) in order to analyze categorical data for testing nine (9) null hypotheses. Statistically significant results were established when p values were < 0.05 at 95% confidence intervals. During the second step-process, qualitative data were generated through focus group discussions with 30 participants, in-depth interviews with 16 key informants, and participant observations and subjected to iterative thematic content analysis. The findings revealed that income, village's geographical location, farming system, membership to farmer-based group, competitive price for produce, credit, age, education, and extension service positively influenced farmers' adoption of adaptation strategies while workforce and perceived risk of rain on crop yields negatively influenced farmers' adoption of adaptation strategies. Thus, it was concluded that farmers' adaptation intent and adoption of adaptation strategies in the study area were largely explained by objective adaptive capacity rather than cognitive factors.


Subject(s)
Climate Change , Farmers , Humans , Tanzania , Cross-Sectional Studies , Farms , Agriculture/methods
6.
Environ Geochem Health ; 45(6): 4007-4023, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36631578

ABSTRACT

Intensive urban agriculture is expanding in Cameroon, which increases the risks of environmental pollution, particularly in the lowlands. This study assessed the seasonal characteristics of some potentially toxic elements and their ecological risks during the dry and wet seasons in urban agricultural soils in four lowlands in Yaoundé. The area and seasonal variation of some potentially toxic elements (Cu, Pb, Zn, Cd, Cr, and Ni) were evaluated using mixed-effects modeling. The pollution status of these elements in the soil was evaluated and interpreted using parameters such as the single pollution (SPI) and Nemerow composite pollution (NCPI) indices. In addition, the effect of these metals in the environment was assessed using the potential ecological risk index (PERI). The distribution of all the studied elements showed an area effect, while a seasonal effect was only noticeable for Cu. The concentration of Cu, Pb, and Zn was higher than the recommended threshold values in one of the areas sampled, while Cr exceeded these threshold values in all areas during both seasons. Cr exhibited the highest SPI among all studied elements during the dry and wet seasons in all areas. Except for the NCPI in one area, where grade V (strong) soil pollution was recorded during the wet season, the soil from all the study areas exhibited a slight pollution level (grade III) with a mean NCPI between 1 and 2. The PERI value of all areas was below the reference values during both seasons, suggesting an overall low potential contamination risk of the soil biota. The results indicate that preventive action to limit the heavy metal contamination in the lowlands of Yaoundé needs to be taken, for instance, through the promotion of more sustainable use of agrochemicals like pesticides and mineral fertilizers.


Subject(s)
Metals, Heavy , Soil Pollutants , Seasons , Environmental Monitoring , Cameroon , Lead , Risk Assessment , Soil Pollutants/analysis , Agriculture , Soil , Metals, Heavy/analysis , China
7.
Malar J ; 22(1): 34, 2023 Jan 31.
Article in English | MEDLINE | ID: mdl-36717848

ABSTRACT

BACKGROUND: The use of urban lowlands for agriculture contributes to the food security of city- dwellers, but promotes malaria transmission. The objective of the study was to characterize the entomological drivers of malaria transmission in two lowlands (N'Gattakro and Odiennekourani) in the city of Bouaké, Côte d'Ivoire. METHODS: The human landing catch technique was used to capture mosquitoes in houses located at the edge of two lowlands in Bouaké from February to December 2019. Cultivated surfaces were calculated monthly in both lowlands for each crop type (rice and market gardening) using images acquired by a drone. The different mosquito species were identified morphologically and by PCR analysis for the Anopheles gambiae complex. Anopheles infection by Plasmodium parasites was assessed by quantitative PCR. Mosquito diversity, biting behaviour and rhythmicity, and malaria transmission were determined in each lowland and compared. RESULTS: Anopheles gambiae sensu lato (s.l.) was predominant in N'Gattakro and Culex quinquefasciatus in Odiennekourani. Four Anopheles species were identified: An. gambiae s.l. and Anopheles funestus s.l. in both lowlands, Anopheles pharoensis in N'Gattakro, and Anopheles ziemanni in Odiennekourani. Within the An. gambiae complex, three species were caught: An. gambiae sensu stricto (s.s.), Anopheles coluzzii, and Anopheles arabiensis for the first time in Côte d'Ivoire (30.1%, 69.9% and 0% in N'Gattakro, and 45.1%, 52.6% and 2.4% in Odiennekourani, respectively). Anopheles gambiae s.l. species exhibited a significant exophagic behaviour in N'Gattakro (77.1% of outdoor bites versus 52.2% in Odiennekourani). In N'Gattakro, 12.6% of captures occurred before bedtime (09.00 pm) and after waking up (05.00 am), 15.1% in Odiennekourani. The mean human biting rate was higher in N'Gattakro than in Odiennekourani (61.6 versus 15.5 bites per person per night). Overall, Anopheles infection rate was 0.68%, with 0.539 and 0.029 infected bites per person per night in N'Gattakro and Odiennekourani, respectively. CONCLUSION: The risk of malaria in urban agricultural lowland areas is uneven. The role of agricultural developments and irrigation patterns in the production of larval habitat should be explored. The exophagic behaviour of Anopheles vectors raises the question of the residual transmission that needs to be assessed to implement appropriate control strategies.


Subject(s)
Anopheles , Malaria , Animals , Humans , Cote d'Ivoire , Mosquito Vectors , Malaria/prevention & control , Anopheles/parasitology , Cities
8.
Heliyon ; 8(12): e12055, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36506405

ABSTRACT

Vulnerable people do not always absorb the occurring shocks instead they react to disasters employing multiple strategies. This study mainly aims to explore households' vulnerability management practices and their linkages with sustainable livelihood security in the drought-prone Gamo lowland setup. Through the multistage sampling technique, a total of 285 respondents were selected from the four sample kebeles. Primary data were collected using a survey questionnaire, key informant interviews, focus group discussions, and field observations. Secondary data were drawn from published and unpublished materials. A mix of the qualitative dominant mixed methods of data analysis was employed. The newly formulated Vulnerability Management for Survival (VMS) framework is used to schematize people's survival strategies and challenges. It was found that the Gamo lowland households pursue multiple vulnerability management practices like liquidation, adopting drought-resistant crops, livelihood diversification, destocking, engagements in off-farm activities, remittance, and reciprocity. These practices are linked with households' livelihood security wherein effective management of vulnerabilities yields secured and sustained livelihoods among the implications. To sustainably enhance rural invulnerability, strengthening people's survival strategies like reciprocity, participation in financial institutions, water harvesting, area closure, afforestation and reforestation, and access to information are recommended.

9.
FEMS Microbiol Ecol ; 98(9)2022 08 25.
Article in English | MEDLINE | ID: mdl-35867879

ABSTRACT

Due to their potential applications for food safety, there is a growing interest in rice root-associated microbial communities, but some systems remain understudied. Here, we compare the assemblage of root-associated microbiota in rice sampled in 19 small farmer's fields from irrigated and rainfed lowlands in Burkina Faso, using an amplicon metabarcoding approach of the 16S rRNA gene (prokaryotes, three plant samples per field) and ITS (fungi, one sample per field). In addition to the expected structure by root compartments (root vs rhizosphere) and geographical zones, we showed that the rice production system is a major driver of microbiome structure. In irrigated systems, we found a higher diversity of prokaryotic communities from the rhizosphere and more complex co-occurrence networks, compared to rainfed lowlands, while fungal communities exhibited an opposite pattern (higher richness in rainfed lowlands). Core taxa were different between the two systems, and indicator species were identified: mostly within Bacillaceae in rainfed lowlands, and within Burkholderiaceae and Moraxellaceae in irrigated areas. Finally, a higher abundance in rainfed lowlands was found for mycorrhizal fungi (both compartments) and rhizobia (rhizosphere only). Our results highlight deep microbiome differences induced by contrasted rice production systems that should consequently be considered for microbial engineering applications.


Subject(s)
Microbiota , Oryza , Burkina Faso , Farmers , Fungi/genetics , Humans , Oryza/microbiology , Plant Roots/microbiology , RNA, Ribosomal, 16S/genetics , Rhizosphere , Soil Microbiology
10.
Environ Monit Assess ; 193(7): 453, 2021 Jun 28.
Article in English | MEDLINE | ID: mdl-34181091

ABSTRACT

Rangeland in Bale lowlands has been seriously degraded due to human-induced problems and natural factors. The study was conducted to analyze LULC change and its deriving factors and evaluate the impacts of rangeland dynamics on livestock mobility in Bale lowlands from 1990-2020. Landsat Thematic Mapper (TM) 1990, Enhanced Thematic Mapper Plus (ETM +) 2000, and Operational Land Imager (OLI) 2014 and 2020 were chosen to derive LULC classes using maximum likelihood image classifier. Besides, a household survey was used to understand the major causes of LULC change, as well as the impacts of rangeland dynamics on livestock mobility. The accuracy reports of classified LULC classes of the study were 88.2% (1990), 89.19% (2000), 93.8% (2014), and 95.2% (2020). The result of the study revealed that there was extreme bush encroachment (545.54%), expansion of settlement (19,166%), and farmland (171.27%) while forest cover has slightly decreased (-8.76%) from 1990 to 2020. On the other hand, shrubland (-72.74%) and grassland (-59.2%) have extremely declined. During the study period, rangeland of Bale lowlands was degraded with annual rate of -0.8%. The study also revealed that expansion of farmland, settlement, communal land, and bush encroachment was the main driving factors for LULC change in Bale lowlands. Bale pastoralists are vulnerable to the death of their livestock, and they need to travel long distances because of rapid rangeland degradation. Therefore, suitable land-use and management policies for pastoral communities should be formulated and implemented so as to permanently mitigate the problem.


Subject(s)
Conservation of Natural Resources , Livestock , Agriculture , Animals , Environmental Monitoring , Ethiopia , Humans
11.
Environ Monit Assess ; 193(2): 95, 2021 Jan 28.
Article in English | MEDLINE | ID: mdl-33507413

ABSTRACT

The Republic of Azerbaijan suffers from low agricultural productivity caused by soil salinization and erosion, and limited and insufficient soil data are available for economic and political reasons. In this study, soil salinity and heavy metal levels were assessed. Environmental risk assessment was conducted to evaluate the potential risk posed by soils to human health. Soil guideline values were proposed to monitor soil pollution in the Republic of Azerbaijan. Water extraction and spatial variability analysis were conducted to understand soil salinization and heavy metal pollution. Among the 20 studied elements, the elements Ca, Cl, and S and the heavy metals Cr, Ni, and Pb were classified as problematic on the basis of the geoaccumulation index, and As was also identified as posing a possible risk on the basis of the potential ecological risk index. Based on the developed soil guideline values for agricultural soil, the As, Cr, and Ni in the soil samples exceeded their respective guidelines by 31.3, 41.8, and 61.6%, respectively. Water extraction results confirmed that 99% of the leached ions were cationic salts, and the most problematic ion was Na, followed by Ca, Cl, and S. The extractability values of Cr and Ni were significantly lower than those of other heavy metals, which implies that their actual leaching potential may be overestimated. The linear regression and spatial variability analysis confirmed that leachable salts have accumulated in lowland areas due to the capillary rise of water and evaporation, but the distribution of heavy metals confirmed that As, Cr, and Ni were abundant in agricultural soils. Our results clearly showed that heavy metal soil contamination and high salinity levels are major problems that should be considered when assessing food safety and health hazards in the Mugan Plain of Azerbaijan. Therefore, future studies should be performed for additional environmental risk assessment, detailed hazard identification, and health risk assessment.


Subject(s)
Metals, Heavy , Soil Pollutants , Azerbaijan , China , Environmental Monitoring , Humans , Metals, Heavy/analysis , Risk Assessment , Salinity , Soil , Soil Pollutants/analysis
12.
Ethn Health ; 26(8): 1261-1274, 2021 11.
Article in English | MEDLINE | ID: mdl-31072126

ABSTRACT

Objective: To relate the socio-demographic profile with access to health services of the population living in environmentally degraded areas in an estuary region.Study design: A sectional field study of 8819 people, evaluating three contaminated areas of São Vicente.Methods: Households were divided by studied area. A structured and pre-tested questionnaire was applied to obtain the data. A probabilistic sample was used. The prevalence of each of the outcomes of interest by area was calculated. To verify the existence of an association between the outcomes of interest and other variables (qualitative), by area, a descriptive analysis and to compare percentages and a comparison test was used between two proportions, a Chi-square test and/or a Fisher's exact test and a Kruska-wallis and Dunn multiple comparison were used as well. The significance level was 5%.Results: Most residents (94%) reported the use of public health services at least once a year (p < 0.001), mainly through the Basic Health Units (BHU) (p < 0.001). Most of the studied population (65%) did not have private health insurance and their schooling was basically restricted to primary education (p < 0.001). The predominant family income (70%) in the three areas was between one and five minimum wages (p < 0.001), with a higher incidence of people receiving one to three minimum wages at the time. The demand for health services was not associated with education or income.Conclusion: The population of the regions analysed heavily rely on the Unified Health System - SUS, but there was no association between income and frequency of health services and there was also no association between education and use of health services.


Subject(s)
Estuaries , Health Services , Brazil/epidemiology , Humans , Income , Prevalence
13.
Biol Rev Camb Philos Soc ; 96(2): 408-432, 2021 04.
Article in English | MEDLINE | ID: mdl-33140559

ABSTRACT

Peat layers are well represented in the Holocene coastal deposits of the southern North Sea and provide evidence as to the extent and nature of the fens and bogs that occupied the region in the mid and late Holocene. While natural processes contributed to their demise, without human interference extensive areas of peatland would remain. We review the characteristics of the vegetation of these peatlands along with the processes that influenced their development. Spatial and temporal trends are explored through the use of palaeogeographic maps from three areas: the East Anglian Fenland, the Romney Marsh area and the Netherlands. The palaeoecological evidence indicates that eutrophic vegetation promoted by rising relative sea level (RSL) dominated in the mid Holocene, with a trend towards the development of oligotrophic and ombrotrophic vegetation in the late Holocene as the rate of RSL rise declined. Nevertheless, areas of eutrophic vegetation appear capable of long-term stability with areas of fen woodland and herbaceous fen persisting at some locations for several thousand years in the mid and late Holocene. Areas of active peat growth in the region are now largely confined to small remnants within agricultural settings. To retain their characteristic biodiversity these remnants have been managed using traditional practices, although their small size and fragmented distribution limits their biodiversity value. Biodiversity concerns and the ecosystem services peatlands provide, notably carbon sequestration and flood attenuation, underlie recent restoration projects. These efforts are likely to receive additional impetus as a consequence of rising water levels, given projected rates of RSL rise. Future large-scale restoration can be informed by a greater understanding of the processes that formed and sustained coastal peatlands in the past. We identify advances in palaeoenvironmental research that could enhance restoration efforts and help maximise the ecosystem services delivered through such projects.


Subject(s)
Ecosystem , Soil , Carbon , Humans , North Sea , Wetlands
14.
BMC Public Health ; 20(1): 320, 2020 Mar 12.
Article in English | MEDLINE | ID: mdl-32164610

ABSTRACT

BACKGROUND: Seasonal migrant and permanent laborers who are working in big mechanized agricultural farms in Metema - Humera lowlands are not included in Ethiopia Malaria Elimination Program. The aim of this research was to show the high confirmed and treated malaria cases in these laborers. METHODS: A retrospective analysis of the confirmed and treated malaria cases in all the districts of West, Central and North Gondar Zones, using Weekly Public Health Emergency Management (PHEM) reports, was conducted to show a complete picture of the malaria incidences in the areas. RESULT: A total of 3,485,646 confirmed malaria cases were treated in Amhara region during 2013 to 2017. Of the total malaria cases in the Amhara region during these period, 1, 286, 848 cases or 37.2% were originated from West, Central and North Gondar Zones. But these 3 Zones contribute only 17% of Amhara region population. Of all the confirmed malaria cases reported in the 3 Zones, 41.7% (536,749/1286, 848) was reported from the three lowland districts (Metema, West Armachiho and Quara) of the West Gondar Zone during the same study period. But, the West Gondar Zone has only around 10% of the population in these three zones. The highest annual parasite incidence for malaria was found in West Armachiho district. Majority of above 14 years malaria cases in West Gondar zone were found from laborers. CONCLUSION: Migrant and permanent laborers working in mechanized agricultural fields in Metema - Humera lowlands are highly exposed to malaria and immediate interventions are required.


Subject(s)
Disease Eradication , Farmers/statistics & numerical data , Malaria/epidemiology , Malaria/prevention & control , Transients and Migrants/statistics & numerical data , Adult , Ethiopia/epidemiology , Farms , Humans , Incidence , Male , Program Evaluation , Retrospective Studies , Seasons
15.
PeerJ ; 7: e7044, 2019.
Article in English | MEDLINE | ID: mdl-31275740

ABSTRACT

The amphibian skin microbiome has been the focus of recent studies aiming to better understand the role of these microbial symbionts in host defense against disease. However, host-associated microbial communities are complex and dynamic, and changes in their composition and structure can influence their function. Understanding temporal variation of bacterial communities on amphibian skin is critical for establishing baselines from which to improve the development of mitigation techniques based on probiotic therapy and provides long-term host protection in a changing environment. Here, we investigated whether microbial communities on amphibian skin change over time at a single site. To examine this, we collected skin swabs from two pond-breeding species of treefrogs, Agalychnis callidryas and Dendropsophus ebraccatus, over 4 years at a single lowland tropical pond in Panamá. Relative abundance of operational taxonomic units (OTUs) based on 16S rRNA gene amplicon sequencing was used to determine bacterial community diversity on the skin of both treefrog species. We found significant variation in bacterial community structure across long and short-term time scales. Skin bacterial communities differed across years on both species and between seasons and sampling days only in D. ebraccatus. Importantly, bacterial community structures across days were as variable as year level comparisons. The differences in bacterial community were driven primarily by differences in relative abundance of key OTUs and explained by rainfall at the time of sampling. These findings suggest that skin-associated microbiomes are highly variable across time, and that for tropical lowland sites, rainfall is a good predictor of variability. However, more research is necessary to elucidate the significance of temporal variation in bacterial skin communities and their maintenance for amphibian conservation efforts.

16.
Ecol Evol ; 9(8): 4917-4930, 2019 Apr.
Article in English | MEDLINE | ID: mdl-31031954

ABSTRACT

Numerous species of amphibians declined in Central America during the 1980s and 1990s. These declines mostly affected highland stream amphibians and have been primarily linked to chytridiomycosis, a deadly disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). Since then, the majority of field studies on Bd in the Tropics have been conducted in midland and highland environments (>800 m) mainly because the environmental conditions of mountain ranges match the range of ideal abiotic conditions for Bd in the laboratory. This unbalanced sampling has led researchers to largely overlook host-pathogen dynamics in lowlands, where other amphibian species declined during the same period. We conducted a survey testing for Bd in 47 species (n = 348) in four lowland sites in Costa Rica to identify local host-pathogen dynamics and to describe the abiotic environment of these sites. We detected Bd in three sampling sites and 70% of the surveyed species. We found evidence that lowland study sites exhibit enzootic dynamics with low infection intensity and moderate to high prevalence (55% overall prevalence). Additionally, we found evidence that every study site represents an independent climatic zone, where local climatic differences may explain variations in Bd disease dynamics. We recommend more detection surveys across lowlands and other sites that have been historically considered unsuitable for Bd occurrence. These data can be used to identify sites for potential disease outbreaks and amphibian rediscoveries.

17.
Anim Genet ; 50(1): 42-53, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30474213

ABSTRACT

Ethiopia is an ecologically diverse country; the low altitude regions are hot and humid whereas the high altitude regions are cooler. In this study we analyzed the transcriptome response of high altitude (Addis Ababa) and low altitude (Awash) chickens to heat stress conditions that are prevalent in the low altitude regions. The chickens were free ranged for 20 h in an enclosure in Awash, and then the heart, breast muscle and spleen tissues were collected at 6:00 am, 12:00 noon and 6:00 pm to follow a daily circadian cycle. Through RNA-sequencing analysis, we identified differentially expressed genes (DEGs) that were significant (q < 0.05). These DEGs were subjected to protein-protein interaction (PPI) network and gene co-expression network (GCN) analyses to understand their role. KEGG pathway analysis and Gene Ontology analysis of all the identified DEGs and the genes identified from the PPI network and GCN analyses revealed that several immune-related pathways, such as proteasome, focal adhesion, influenza A, the ErbB signaling pathway and glycerophospholipid metabolism, were enriched in response to heat stress. These results suggest that the high altitude chickens were under heat stress and might be immunologically susceptible. Our findings will help in developing a genetic approach to mitigate production loss due to heat stress.


Subject(s)
Altitude , Chickens/immunology , Heat-Shock Response/immunology , Transcriptome , Animals , Chickens/genetics , Cluster Analysis , Ethiopia , Gene Expression Profiling , Male
18.
PeerJ ; 6: e5886, 2018.
Article in English | MEDLINE | ID: mdl-30498628

ABSTRACT

Grasslands in southern South America are extensive ecosystems which harbor a unique biodiversity; however, studies on the evolution of their taxa are scarce. Here we studied the phylogeography and population history of the Correndera Pipit (Anthus correndera), a grassland specialist bird with a large breeding distribution in southern South America, with the goals of investigating its phylogeographic history and relate it to the historical development of South American grasslands. The mitochondrial NADH dehydrogenase subunit II gene (ND2) was sequenced in 66 individuals from 19 localities and the intron 9 of the sex-linked gene for aconitase (ACOI9) was sequenced from a subset of those individuals, including all five subspecies of A. correndera, as well as the closely related A. antarcticus. Phylogenetic analysis revealed two distinct lineages within the complex: the first (A) corresponding to Andean subspecies A. c. calcaratus and A. c. catamarcae and the second (B) including birds traditionally assigned to A. c. correndera, A. c. chilensis, A. c. grayi and some individuals of A. c. catamarcae. A. antarcticus is nested within this second lineage. These results were also supported by evidence of niche divergence for variables associated with precipitation. The oldest split between clade A and B was estimated at c. 0.37 Mya, during the middle Pleistocene. Species distribution models for the present and the Last Glacial Maximum (LGM) suggest that grassland areas in southern South America remained relatively stable, in contrast to the general view of a reduction in grassland cover in South America since the LGM. Recent divergences and low phylogeographic structure (for lowland vs. highland geographic groups, intra-population genetic variance was greater than inter-groups; e.g., for ACOI9: 95.47% and ND2: 51.51% respectively), suggest widespread gene flow between lowland populations.

19.
Ambio ; 47(8): 908-923, 2018 Dec.
Article in English | MEDLINE | ID: mdl-29532402

ABSTRACT

It has been suggested that traditional ecological knowledge (TEK) may play a key role in forest conservation. However, empirical studies assessing to what extent TEK is associated with forest conservation compared with other variables are rare. Furthermore, to our knowledge, the spatial overlap of TEK and forest conservation has not been evaluated at fine scales. In this paper, we address both issues through a case study with Tsimane' Amerindians in the Bolivian Amazon. We sampled 624 households across 59 villages to estimate TEK and used remote sensing data to assess forest conservation. We ran statistical and spatial analyses to evaluate whether TEK was associated and spatially overlapped with forest conservation at the village level. We find that Tsimane' TEK is significantly and positively associated with forest conservation although acculturation variables bear stronger and negative associations with forest conservation. We also find a very significant spatial overlap between levels of Tsimane' TEK and forest conservation. We discuss the potential reasons underpinning our results, which provide insights that may be useful for informing policies in the realms of development, conservation, and climate. We posit that the protection of indigenous cultural systems is vital and urgent to create more effective policies in such realms.


Subject(s)
Conservation of Natural Resources/statistics & numerical data , Ecology/education , Forests , Acculturation , Biodiversity , Bolivia , Cross-Sectional Studies , Environment , Family Characteristics , Humans , Knowledge , Regression Analysis , Spatial Analysis
20.
Data Brief ; 14: 804-812, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28971116

ABSTRACT

This article contains the data on farmers' determinants of binary choices for manure use (i.e., manure is used or unused) and fertiliser use (i.e., fertiliser is used or unused) at their fields in semi-arid northern Ethiopian Rift Valley. The data includes (i) a schematic diagram that represents local farmers' distinctions of the crop field types in terms of the distance from their houses and soil fertility and (ii) a table that describes a representative farmer's crop sequences and soil fertilisation methods in two consecutive years. Details about the literature review of the previous case studies on farmers' determinants of manure application technique adoption conducted in some parts of sub-Saharan Africa where cattle dung is used for manure are also summarized in a table. A table shows descriptive statistics of the independent variables used in the empirical analyses. Summary statistics of 4 binomial logit models and 4 multinomial logit models are indicated in a table, which represent model fit. Last two tables exhibited in this article show the logit analyses.

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