scholarly journals Niche characteristics and potential distribution of Thelocactus species, a Mexican genus of globular cacti

2017 ◽  
Author(s):  
Alessandro Mosco
Keyword(s):  
Environmental Factors ◽  
Null Hypothesis ◽  
Ecological Niche ◽  
Potential Distribution ◽  
Environmental Niche ◽  
Distribution Maps ◽  
Species Pairs ◽  
Ordination Techniques ◽  
Environmental Niche Models ◽  
High Degree

AbstractAimAlthough Mexican Cactaceae are a significative component of Mexican flora and have a relevant economic and ornamental value, the knowledge of the environmental factors characterising their niche is still quite incomplete. This study was aimed at defining the potential distribution and ecological niche of Thelocactus species.MethodsClimatic and environmental variables constraining the distribution of Thelocactus species were identified by means of environmental niche models (ENM) and ordination techniques, and used to generate potential distribution maps. The constructed ENMs were compared to assess the similarities of the ecological niche of Thelocactus species and to know if they share the same ecological niche space.ResultsThe distribution of Thelocactus species was mostly limited by a combination of two environmental factors, isothermality and precipitation of wettest quarter. The null hypothesis of the niche equivalency test was rejected for all paired comparisons between all Thelocactus species except between the pair Thelocactus leucacanthus-Thelocactus hastifer. The results of the niche similarity tests were quite varied, for some species pairs the niche similarities were higher than expected by chance, for others the null hypothesis was rejected, while in other species pairs niches were more similar than expected by chance, but only in one direction.Main conclusionsThe differences in habitat requirements were well documented by the significative differences in the niche ecological space as shown by the equivalency test, while the high percentage of niches that were more similar than expected by chance suggest a high degree of niche conservatism among Thelocactus species. The spatial predictions could serve to improve field design sampling to discover new populations, while niche characteristics could be relevant for improving preservation actions and guiding reintroduction programs for a better conservation of Thelocactus species.

scholarly journals Mapping suitability for Buruli ulcer at fine spatial scales across Africa: a modelling study

2020 ◽  
Author(s):  
Hope Simpson ◽  
Earnest Njih Tabah ◽  
Richard Phillips ◽  
Michael Frimpong ◽  
Issaka Maman ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Ecological Niche ◽  
Neglected Tropical Diseases ◽  
Spatial Scales ◽  
Buruli Ulcer ◽  
Local Variation ◽  
Mycobacterium Ulcerans ◽  
Range Data ◽  
Environmental Niche ◽  
Endemic Areas

AbstractBackgroundBuruli ulcer (BU) is a disabling and stigmatising neglected tropical disease (NTD). Its distribution and burden are unknown because of underdiagnosis and underreporting. It is caused by Mycobacterium ulcerans, an environmental pathogen whose environmental niche and transmission routes are not fully understood. Active BU case searches can limit morbidity by identifying cases and linking them to treatment, but these are mostly restricted to well-known endemic areas. A better understanding of environmental suitability for environmental reservoirs of M. ulcerans and BU disease would advance understanding of the disease’s ecology and burden, and could inform targeted surveillance.Methodology/Principal FindingsWe used previously compiled point-level datasets of BU and M. ulcerans occurrence, evidence for BU occurrence within national and sub-national areas, and diverse environmental datasets. We fitted relationships between BU and M. ulcerans occurrence and environmental predictors by applying regression and machine learning based algorithms, combined in an ensemble model to characterise the optimal ecological niche for the disease and bacterium across Africa at a resolution of 5km × 5km. Climate and atmospheric variables were the strongest predictors of both distributions, while indicators of human disturbance including damming and deforestation, drove local variation in suitability. We identified patchy foci of suitability throughout West and Central Africa, including areas with no previous evidence of the disease. Predicted suitability for M. ulcerans was wider but overlapping with that of BU. The estimated population living in areas predicted suitable for the bacterium and disease was 29.1 million.Conclusions/SignificanceThese maps could be used to inform burden estimations and case searches which would generate a more complete understanding of the spatial distribution of BU in Africa, and may guide control programmes to identify cases beyond the well-known endemic areas.Author summaryLike many neglected tropical diseases primarily affecting the rural poor, Buruli ulcer (BU) is under-detected and under-reported within routine health information systems. As such, the burden and distribution are not fully known, impeding appropriate targeting of health resources, control, and care for people affected. Having previously evaluated and mapped the existing evidence for BU and its causative agent M. ulcerans, we concluded that the disease was likely to occur beyond the range of known endemic areas. However, we were left with the question of where exactly these undetected cases might be occurring. Answering this question required a more fine-scale approach: BU is highly focal, presumably due to local variation in the environmental factors which determine suitability for M. ulcerans survival and transmission to humans. We used the compiled evidence and geographical datasets to build statistical models representing the relationship between environmental factors and previously reported cases. This allowed us to define the ecological niche of BU, and subsequently to identify areas across Africa where this niche was met, providing suitable conditions for the disease. We constructed separate models of suitability for M. ulcerans, using locations where its DNA had been detected in environmental sources. Unsurprisingly, suitability for M. ulcerans was predicted to be wider than, but geographically overlapping with that for BU. This implies that beyond the conditions necessary for survival of the bacterium, additional factors are required for transmission to humans. The high-resolution suitability maps we present are intended to guide case search activities which may identify endemic areas beyond the known endemic range. Data on the true prevalence of BU from targeted case searches within predicted-suitable areas will also allow us to validate and refine the models, and potentially predict the actual probability of cases occurring within predicted suitable areas.

scholarly journals Potential geographical distribution and environmental explanations of rare and endangered plant species through combined modelling: A case study of Northwest Yunnan, China

2020 ◽  
Author(s):  
Pengcheng Ye ◽  
Guangfu Zhang ◽  
Xiao Zhao ◽  
Hui Chen ◽  
Qin Si ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Distribution Pattern ◽  
Geographical Distribution ◽  
Plant Species ◽  
Ecological Niche ◽  
Potential Distribution ◽  
Distribution Patterns ◽  
Endangered Plant ◽  
Rare And Endangered ◽  
Geographical Distribution Pattern

In recent decades, due to the effect of climate change and the interference of human activities, the species habitat index fallen 2%. Studying the geographical distribution pattern and predicting the potential geographical distribution of species are of great significance for developing scientific and effective biodiversity conservation strategies. The purpose of this research is to predict the potential geographical distribution of 25 rare and endangered plant species in Northwest Yunnan, China on the grid map with a resolution of 0.05° × 0.05° and analyze the explanation capabilities of various environmental factors on the potential geographical distribution patterns of these species, and explore the main restrictive environmental factors. Initially, we employed the ecological niche model MaxEnt to predict the potential geographical distribution of target species. Following that, we overlaid the potential geographical distribution of each species, and we obtained the potential geographical distribution pattern of species richness on the spatial scale of the ecological niche model with a resolution of 0.05° × 0.05°. Ultimately, we also adopted geographically weighted regression (GWR) model to investigate the explanation capabilities of various environmental parameters on the potential distribution patterns. The results showed that the average AUC value of each species was between 0.80 and 1.00, which indicated that the simulation precision of the MaxEnt model for each species was good or excellent. Besides, the potential distribution areas of these species were between 826.33 km2 and 44,963.53 km2. In addition, the average contribution values of the annual precipitation (Bio12), precipitation of coldest quarter (Bio19) and population density (Pop) were 25.92%, 15.86% and 17.95%, respectively. Moreover, the goodness of fit R2 and AIC value of the water model were 0.88 and 7,703.82, respectively, which indicated the water factor largely influenced the potential distribution of these species. The results of this study would be helpful for implementing long-term conservation and reintroduction for these species.

scholarly journals Projections for Mexico’s Tropical Rainforests Considering Ecological Niche and Climate Change

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 119
Author(s):  
Antonio Fidel Santos-Hernández ◽  
Alejandro Ismael Monterroso-Rivas ◽  
Diódoro Granados-Sánchez ◽  
Antonio Villanueva-Morales ◽  
Malinali Santacruz-Carrillo
Keyword(s):  
Climate Change ◽  
Ecological Niche ◽  
Potential Distribution ◽  
Tropical Rainforest ◽  
Statistical Significance ◽  
Climate Change Scenarios ◽  
Climate Conditions ◽  
Tropical Regions ◽  
Temperature And Precipitation ◽  
Ecological Importance

The tropical rainforest is one of the lushest and most important plant communities in Mexico’s tropical regions, yet its potential distribution has not been studied in current and future climate conditions. The aim of this paper was to propose priority areas for conservation based on ecological niche and species distribution modeling of 22 species with the greatest ecological importance at the climax stage. Geographic records were correlated with bioclimatic temperature and precipitation variables using Maxent and Kuenm software for each species. The best Maxent models were chosen based on statistical significance, complexity and predictive power, and current potential distributions were obtained from these models. Future potential distributions were projected with two climate change scenarios: HADGEM2_ES and GFDL_CM3 models and RCP 8.5 W/m2 by 2075–2099. All potential distributions for each scenario were then assembled for further analysis. We found that 14 tropical rainforest species have the potential for distribution in 97.4% of the landscape currently occupied by climax vegetation (0.6% of the country). Both climate change scenarios showed a 3.5% reduction in their potential distribution and possible displacement to higher elevation regions. Areas are proposed for tropical rainforest conservation where suitable bioclimatic conditions are expected to prevail.

scholarly journals Predicting the potential distribution of the vase tunicate Ciona intestinalis in Canadian waters: informing a risk assessment

2008 ◽  
Vol 65 (5) ◽  
pp. 788-794 ◽  
Author(s):  
Thomas W. Therriault ◽  
Leif-Matthias Herborg
Keyword(s):  
Risk Assessment ◽  
Native Species ◽  
Potential Distribution ◽  
Negative Impact ◽  
Ciona Intestinalis ◽  
Environmental Niche ◽  
Environmental Models ◽  
Introduced Range ◽  
Negative Impacts ◽  
Almost All

Abstract Therriault, T. W., and Herborg, L-M. 2008. Predicting the potential distribution of the vase tunicate Ciona intestinalis in Canadian waters: informing a risk assessment. – ICES Journal of Marine Science, 65: 788–794. A crucial step in characterizing the potential risk posed by non-native species is determining whether a potential invader can establish in the introduced range and what its potential distribution could be. To this end, various environmental models ranging from simple to complex have been applied to predict the potential distribution of an invader, with varying levels of success. Recently, in marine waters, tunicates have received much attention, largely because of their negative impacts on shellfish aquaculture. One of these species is the vase tunicate Ciona intestinalis, which recently has had a negative impact on aquaculture operations in Atlantic Canada and could pose a risk in Pacific Canada. To inform the risk assessment of this species, we evaluated two different types of environmental model. Simple models based on reported temperature or salinity tolerances were relatively uninformative, because almost all waters were deemed suitable. In contrast, a more complex genetic algorithm for rule-set prediction (GARP) environmental niche model, based on documented Canadian occurrence points, provided informative projections of the potential distribution in Canadian waters. In addition to informing risk assessments, these predictions can be used to focus monitoring activities, particularly towards vectors that could transport C. intestinalis to these favourable environments.

scholarly journals The rooting, survival and growth of woody species on tailing dumps in the limestone quarry “Lafarge ciment”

2021 ◽  
Vol 13 (1(22)) ◽  
pp. 34-42
Author(s):  
Petru Cuza ◽  
◽  
Corina Certan ◽  
Constantin Bulimaga ◽  
◽  
...  
Keyword(s):  
Growth Rate ◽  
Environmental Factors ◽  
Slow Growth ◽  
Woody Species ◽  
Mineral Elements ◽  
Black Pine ◽  
Limestone Quarry ◽  
Survival And Growth ◽  
High Degree ◽  
Fast Growing Species

The rooting, the survival and dynamics of growths in the height and after the diameter of the seedlings, of a range of woody species, had investigated on the freshly formed sterile dump limestone quarry „Lafarge Ciment”. The seedlings of the woody species had a relatively good rooting (69-99%). A high degree of rooting can be ensured as a result of the maintenance of forest crops. After planting, the young seedlings must be cared for by hoeing as many times as necessary in order to control the weeds and maintain moisture in the soil, which increases the survival of the seedlings. Tree species have been characterized by a different growth rate. Acacia has showed a very rapid increase in height, but the black pine has been characterized by a slow growth. Acacia being a fast-growing species and unpretentious to the mineral elements in the soil can be used to afforest the limestone quarry land. In the fi rst year after planting, the young seedlings, otherwise sensitive to the action of the environmental factors, had an increase in height and in diameter slow and uneven. In the years that followed, the seedlings became more viable and less infl uenced by local and temporal fl uctuations of environmental factors.

Ignoring seasonal changes in the ecological niche of non-migratory species may lead to biases in potential distribution models: lessons from bats

2018 ◽  
Vol 27 (9) ◽  
pp. 2425-2441 ◽  
Author(s):  
Sonia Smeraldo ◽  
Mirko Di Febbraro ◽  
Luciano Bosso ◽  
Carles Flaquer ◽  
David Guixé ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Ecological Niche ◽  
Potential Distribution ◽  
Migratory Species ◽  
Distribution Models

scholarly journals Nested Species Distribution Models of Chlamydiales in Ixodes ricinus (Tick) Hosts in Switzerland

2020 ◽  
Vol 87 (1) ◽  
Author(s):  
Estelle Rochat ◽  
Séverine Vuilleumier ◽  
Sébastien Aeby ◽  
Gilbert Greub ◽  
Stéphane Joost
Keyword(s):  
Environmental Factors ◽  
Ixodes Ricinus ◽  
Vegetation Index ◽  
Respiratory Infections ◽  
Smartphone Application ◽  
Climatic Conditions ◽  
Lower Percentage ◽  
Distribution Models ◽  
Content Type ◽  
Distribution Maps

ABSTRACT The tick Ixodes ricinus is the vector of various pathogens, including Chlamydiales bacteria, which potentially cause respiratory infections. In this study, we modeled the spatial distribution of I. ricinus and associated Chlamydiales over Switzerland from 2009 to 2019. We used a total of 2,293 ticks and 186 Chlamydiales occurrences provided by a Swiss Army field campaign, a collaborative smartphone application, and a prospective campaign. For each tick location, we retrieved from Swiss federal data sets the environmental factors reflecting the topography, climate, and land cover. We then used the Maxent modeling technique to estimate the suitability of particular areas for I. ricinus and to subsequently build the nested niche of Chlamydiales bacteria. Results indicate that I. ricinus habitat suitability is determined by higher temperature and normalized difference vegetation index (NDVI) values, lower temperature during the driest months, and a higher percentage of artificial and forest areas. The performance of the model was improved when extracting the environmental variables for a 100-m radius buffer around the sampling points and when considering the climatic conditions of the 2 years previous to the sampling date. Chlamydiales bacteria were favored by a lower percentage of artificial surfaces, drier conditions, high precipitation during the coldest months, and short distances to wetlands. From 2009 to 2018, we observed an extension of areas suitable to ticks and Chlamydiales, associated with a shift toward higher altitude. The importance of considering spatiotemporal variations in the environmental conditions for obtaining better prediction was also demonstrated. IMPORTANCE Ixodes ricinus is the vector of pathogens including the agent of Lyme disease, the tick-borne encephalitis virus, and the less well-known Chlamydiales bacteria, which are responsible for certain respiratory infections. In this study, we identified the environmental factors influencing the presence of I. ricinus and Chlamydiales in Switzerland and generated maps of their distribution from 2009 to 2018. We found an important expansion of suitable areas for both the tick and the bacteria during the last decade. Results also provided the environmental factors that determine the presence of Chlamydiales within ticks. Distribution maps as generated here are expected to bring valuable information for decision makers in controlling tick-borne diseases in Switzerland and establishing prevention campaigns. The methodological framework presented could be used to predict the distribution and spread of other host-pathogen pairs to identify environmental factors driving their distribution and to develop control or prevention strategies accordingly.

Spatial Risk Distribution of Dengue Based on the Ecological Niche Model of Aedes aegypti (Diptera: Culicidae) in the Central Mexican Highlands

2019 ◽  
Vol 57 (3) ◽  
pp. 728-737
Author(s):  
Raymundo Ordoñez-Sierra ◽  
Carlos Alberto Mastachi-Loza ◽  
Carlos Díaz-Delgado ◽  
Angela P Cuervo-Robayo ◽  
Carlos Roberto Fonseca Ortiz ◽  
...  
Keyword(s):  
Ecological Niche ◽  
Potential Distribution ◽  
Vegetation Index ◽  
Ecological Niche Model ◽  
Distribution Model ◽  
Large Area ◽  
Niche Model ◽  
Spatial Risk ◽  
Precipitation Seasonality ◽  
Risk Distribution

Abstract Dengue is the most important viral disease transmitted by mosquitoes, predominantly Aedes (Stegomyia) aegypti (L.) (Diptera:Culicidae). Forty percent of the world’s population is at risk of contracting the disease, and a large area of Mexico presents suitable environmental conditions for the life cycle of Ae. aegypti. In particular, the Central Mexican Highlands have a high population density, increasing the risk of transmission and propagation of dengue. In the present study, the potential distribution of Ae. aegypti was modeled under an ecological niche approach using the maximum entropy technique with the aim of determining the spatial risk distribution of dengue. The final model of five variables (minimum temperature of the coldest month |Bio6|, precipitation of the wettest month |Bio13|, precipitation seasonality |Bio15|, the normalized difference vegetation index (NDVI), and relative humidity) contributed to more than 90% of the model’s performance. The results of the potential distribution model were then compared with the number of dengue cases per locality during the 2009–2015 period considering four suitability of presence categories. Category 4 corresponded with the highest suitability of presence (0.747 to 1) and the greatest risk of dengue (odds ratio [OR] = 103.27; P < 0.001). In conclusion, the present ecological niche model represents an important tool for the monitoring of dengue and the identification of high-risk areas.

Sign in / Sign up

Export Citation Format

Share Document