scholarly journals Commensal Rodent Habitat Expansion Enhances Arthropod Disease Vectors on a Tropical Volcanic Island

2021 ◽  
Vol 8 ◽  
Author(s):  
De-Lun Wu ◽  
Han-Chun Shih ◽  
Jen-Kai Wang ◽  
Hwa-Jen Teng ◽  
Chi-Chien Kuo
Keyword(s):  
Scrub Typhus ◽  
Hot Spot ◽  
Positive Association ◽  
Volcanic Island ◽  
Natural Habitats ◽  
Human Settlements ◽  
Primary Host ◽  
Orchid Island ◽  
Volcanic Islands ◽  
Suitable Habitats

On volcanic islands, the release of animals from predators and competitors can lead to increased body size and population density as well as the expanded habitat use of introduced animals relative to their mainland counterparts. Such alterations might facilitate the spread of diseases on islands when these exotic animals also carry pathogenic agents; however, this has rarely been investigated. The commensal Asian house rat (Rattus tanezumi) is confined to human residential surroundings in mainland Taiwan but can be observed in the forests of nearby Orchid Island, which is a tropical volcanic island. Orchid Island is also a hot spot for scrub typhus, a lethal febrile disease transmitted by larval trombiculid mites (chiggers) that are infected primarily with the rickettsia Orientia tsutsugamushi (OT). We predicted an increase in chigger abundance when rodents (the primary host of chiggers) invade forests from human settlements since soils are largely absent in the latter habitat but necessary for the survival of nymphal and adult mites. A trimonthly rodent survey at 10 sites in three habitats (human residential, grassland, and forest) found only R. tanezumi and showed more R. tanezumi and chiggers in forests than in human residential sites. There was a positive association between rodent and chigger abundance, as well as between rodent body weight and chigger load. Lastly, >95% of chiggers were Leptotrombidium deliense and their OT infection rates were similar among all habitats. Our study demonstrated potentially elevated risks of scrub typhus when this commensal rat species is allowed to invade natural habitats on islands. Additionally, while the success of invasive species can be ascribed to their parasites being left behind, island invaders might instead obtain more parasites if the parasite requires only a single host (e.g., trombiculid mite), is a host generalist (e.g., L. deliense), and is transferred from unsuitable to suitable habitats (i.e., human settlements on the mainland to forests on an island).

scholarly journals Commensal rodent habitat expansion enhances arthropod disease vectors on a tropical volcanic island

2021 ◽  
Author(s):  
De-Lun Wu ◽  
Han-Chun Shih ◽  
Jen-Kai Wang ◽  
Hwa-Jen Teng ◽  
Chi-Chien Kuo
Keyword(s):  
Scrub Typhus ◽  
Positive Association ◽  
Volcanic Island ◽  
Natural Habitats ◽  
Primary Host ◽  
Exotic Animals ◽  
Single Host ◽  
Orchid Island ◽  
Volcanic Islands ◽  
Suitable Habitats

AbstractRelease from predators and competitors on volcanic islands can lead to increased body size and population density, as well as expanded habitat usage of introduced animals relative to their mainland counterparts. Such alterations might help the spread of diseases on islands when these exotic animals also carry pathogenic agents, but is rarely investigated. The commensal Asian house rat (Rattus tanezumi) is confined to human residential surroundings in Taiwan mainland but can be observed in the primary forests of the nearby Orchid Island, a tropical volcanic island. Orchid Island is also a hotspot of scrub typhus, a lethal febrile disease transmitted by larval trombiculid mites (chiggers) infective of the rickettsia Orientia tsutsugamushi (OT). We predicted an increase in chigger abundance when rodents, the primary host of chiggers, invade forests from human settlements as soils are largely devoid of in the latter habitat but is necessary for the survival of nymphal and adult mites. A trimonthly rodent survey in ten sites of three habitats (human resident, grassland, and forest) found only R. tanezumi and showed more R. tanezumi and chiggers in forest than in human residential sites. There was a positive association between rodent and chigger abundance, as well between rodent body weight and load of chiggers. Lastly, >95% of chiggers were Leptotrombidium deliense and their OT infection rates were similar among the habitats. Our study demonstrated potentially elevated risks of scrub typhus when the commensal rat is allowed to invade natural habitats on islands. In addition, while the success of invasive species can be ascribed to their parasites being left behind, island invaders might instead attain more parasites when the parasite requires only a single host (e.g. trombiculid mite), is a host generalist (L. deliense), and is transferred from unsuitable to suitable habitats (human settlement on mainland to forest on island).

scholarly journals Hydrogeological conceptual model of andesitic watersheds revealed by high-resolution heliborne geophysics

2019 ◽  
Vol 23 (5) ◽  
pp. 2321-2338 ◽  
Author(s):  
Benoit Vittecoq ◽  
Pierre-Alexandre Reninger ◽  
Frédéric Lacquement ◽  
Guillaume Martelet ◽  
Sophie Violette
Keyword(s):  
Hydraulic Conductivity ◽  
Conceptual Model ◽  
Preferential Flow ◽  
Groundwater Resources ◽  
Watershed Scale ◽  
Volcanic Island ◽  
Multidisciplinary Study ◽  
Hydrogeological Characteristics ◽  
Volcanic Islands ◽  
Very High

Abstract. We conducted a multidisciplinary study at the watershed scale of an andesitic-type volcanic island in order to better characterize the hydrogeological functioning of aquifers and to better evaluate groundwater resources. A heliborne Time Domain ElectroMagnetic (TDEM) survey was conducted over Martinique in order to investigate underground volcanic structures and lithology, characterized by high lateral and vertical geological variability and resulting in a very high heterogeneity of their hydrogeological characteristics. Correlations were made on three adjacent watersheds between resistivity data along flight lines and geological and hydrogeological data from 51 boreholes and 24 springs, showing that the younger the formations, the higher their resistivity. Correlation between resistivity, geology and transmissivity data of three aquifers is attested: within the interval 10–100 ohm m and within a range of 1 to 5.5 Ma, the older the formation, the lower its resistivity, and the older the formation, the higher its transmissivity. Moreover, we demonstrate that the main geological structures lead to preferential flow circulations and that hydrogeological watersheds can differ from topographical watersheds. The consequence is that, even if the topographical watershed is small, underground flows from an adjacent watershed can add significant amounts of water to such a catchment. This effect is amplified when lava domes and their roots are situated upstream, as they present very high hydraulic conductivity leading to deep preferential groundwater flow circulations. We also reveal, unlike basaltic-type volcanic islands, that hydraulic conductivity increases with age in this andesitic-type volcanic island. This trend is interpreted as the consequence of tectonic fracturing associated with earthquakes in this subduction zone, related to andesitic volcanic islands. Finally, our approach allows characterization in detail of the hydrogeological functioning and identification of the properties of the main aquifer and aquitard units, leading to the proposition of a hydrogeological conceptual model at the watershed scale. This working scale seems particularly suitable due to the complexity of edifices, with heterogeneous geological formations presenting high lateral and vertical variability. Moreover, our study offers new guidelines for accurate correlations between resistivity, geology and hydraulic conductivity for volcanic islands. Finally, our results will also help stakeholders toward a better management of water resources.

scholarly journals Hydrogeological settings of a volcanic island (San Cristóbal, Galapagos) from joint interpretation of airborne electromagnetics and geomorphological observations

2012 ◽  
Vol 9 (8) ◽  
pp. 9661-9686 ◽  
Author(s):  
A. Pryet ◽  
N. d'Ozouville ◽  
S. Violette ◽  
B. Deffontaines ◽  
E. Auken
Keyword(s):  
Resistivity Structure ◽  
Volcanic Island ◽  
Transient Electromagnetic ◽  
Geophysical Surveys ◽  
Joint Interpretation ◽  
Volcanic Islands ◽  
Definition Of ◽  
Optimum Management ◽  
Perched Aquifers ◽  
Airborne Electromagnetics

Abstract. Many volcanic islands face freshwater stress and the situation may worsen with climate change and sea level rise. In this context, an optimum management of freshwater resources becomes crucial, but is often impeded by the lack of data. With the aim of investigating the hydrogeological settings of Southern San Cristóbal Island (Galapagos), we conducted an helicopter-borne, transient electromagnetic survey with the SkyTEM system. It provided unprecedented insights in the 3-D resistivity structure of this extinct basaltic shield. Combined with remote sensing and fieldwork, it allowed the definition of the first hydrogeological conceptual model of the island. Springs are fed by a series of perched aquifers overlying a regional basal aquifer subject to seawater intrusion. Dykes, evidenced by alignments of eruptive cones at the surface, correspond to sharp sub-vertical contrasts in resistivity in the subsurface, and impound groundwater in a summit channel. Combined with geomorphological observations, airborne electromagnetics is shown to be a useful tool for hydrogeological exploratory studies in complex, poorly known environments. It allows optimal development of land-based geophysical surveys and drilling campaigns.

scholarly journals Hydrogeological conceptual model of andesitic watersheds revealed by high-resolution geophysics

2019 ◽  
Author(s):  
Benoit Vittecoq ◽  
Pierre-Alexandre Reninger ◽  
Frédéric Lacquement ◽  
Guillaume Martelet ◽  
Sophie Violette
Keyword(s):  
Hydraulic Conductivity ◽  
Conceptual Model ◽  
Subduction Zones ◽  
Preferential Flow ◽  
Watershed Scale ◽  
Volcanic Island ◽  
Hydrogeological Characteristics ◽  
Volcanic Islands ◽  
Very High ◽  
Vertical Variability

Abstract. We conducted a multidisciplinary study at the watershed scale of an andesitic-type volcanic island in order to better characterize the hydrogeological functioning of aquifers and to better evaluate groundwater resource. A helicopter-borne TDEM survey was conducted in 2013 over Martinique Island in order to investigate underground volcanic structures and lithology, characterized by high lateral and vertical variability, and resulting in a very high heterogeneity of their hydrogeological characteristics. Correlations were made on three adjacent watersheds between resistivity data along flight lines and geological and hydrogeological data from 51 boreholes and 24 springs, showing that the younger the formations, the higher their resistivity. Correlation between resistivity, geology and transmissivity data of three aquifers is attested: the older the formation, the lower its resistivity, and the higher its transmissivity. Moreover, we demonstrate that the main geological structures lead to preferential flow circulations and that hydrogeological watershed can differ from topographical watershed. The consequence is that even if the topographical watershed is small, underground flow circulations can add significant amount of water to river watershed’s water balance. This effect is amplified when lava domes and their roots are situated upstream, as they present very high hydraulic conductivity leading to deep preferential groundwater flow circulations. We also reveal, unlike basaltic-type volcanic islands, that hydraulic conductivity increases with age in this andesitic-type volcanic island. This trend is interpreted as the consequence of tectonic fracturing associated to earthquakes in subduction zones associated to andesitic volcanic islands. Finally, our approach allows characterizing in detail the hydrogeological functioning and identifying the properties of the main aquifer and aquitard units, leading to the proposition of a hydrogeological conceptual model at the watershed scale. This working scale seems particularly suitable due to the complexity of edifices, with heterogeneous geological formations presenting high lateral and vertical variability. Moreover, our study offers new guidelines for accurate correlations between resistivity, geology and hydraulic conductivity for volcanic islands. Finally, our results will also help stakeholders toward a better management of water resource.

scholarly journals Hydrogeological settings of a volcanic island (San Cristóbal, Galapagos) from joint interpretation of airborne electromagnetics and geomorphological observations

2012 ◽  
Vol 16 (12) ◽  
pp. 4571-4579 ◽  
Author(s):  
A. Pryet ◽  
N. d'Ozouville ◽  
S. Violette ◽  
B. Deffontaines ◽  
E. Auken
Keyword(s):  
Resistivity Structure ◽  
Volcanic Island ◽  
Transient Electromagnetic ◽  
Geophysical Surveys ◽  
Joint Interpretation ◽  
Volcanic Islands ◽  
Definition Of ◽  
Optimum Management ◽  
Perched Aquifers ◽  
Airborne Electromagnetics

Abstract. Many volcanic islands face freshwater stress and the situation may worsen with climate change and sea level rise. In this context, an optimum management of freshwater resources becomes crucial, but is often impeded by the lack of data. With the aim of investigating the hydrogeological settings of southern San Cristóbal Island (Galapagos), we conducted a helicopter-borne, transient electromagnetic survey with the SkyTEM system. It provided unprecedented insights into the 3-D resistivity structure of this extinct basaltic shield. Combined with remote sensing and fieldwork, it allowed the definition of the first hydrogeological conceptual model of the island. Springs are fed by a series of perched aquifers overlying a regional basal aquifer subject to seawater intrusion. Dykes, evidenced by alignments of eruptive cones at the surface, correspond to sharp sub-vertical contrasts in resistivity in the subsurface, and impound groundwater in a summit channel. Combined with geomorphological observations, airborne electromagnetics are shown to be a useful for hydrogeological exploratory studies in complex, poorly known environments. They allow optimal development of land-based geophysical surveys and drilling campaigns.

scholarly journals Modelling Land Sharing and Land Sparing Relationship with Rural Population in the Cerrado

Land ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 88
Author(s):  
João Pompeu ◽  
Luciana Soler ◽  
Jean Ometto
Keyword(s):  
Biodiversity Conservation ◽  
Rural Population ◽  
Environmental Changes ◽  
Positive Association ◽  
Agricultural Activities ◽  
Natural Habitats ◽  
Land Sharing ◽  
Land Sparing ◽  
Agricultural Matrix ◽  
Northern Portion

Agricultural expansion and intensification enabled growth of food production but resulted in serious environmental changes. In light of that, debates concerning sustainability in agriculture arises on scientific literature. Land sharing and land sparing are two opposite models for framing agricultural sustainability. The first aims to integrate agricultural activities with biodiversity conservation by means of enhancing the quality of the agricultural matrix in the landscape towards a wildlife friendly matrix. The other model aims to spare natural habitats from agriculture for conservation. This work aimed to explore spatial evidences of land sharing/sparing and its relationship with rural population in the Brazilian Cerrado. A Land Sharing/Sparing Index based on TerraClass Cerrado map was proposed. Spatial analysis based on Global and Local Moran statistics and Geographically Weighted Regression were made in order to explore the influence of local rural population on the probability of spatial land sharing/sparing clusters occurrence. Spatial patterns of land sharing were found in the Cerrado and a positive association with rural population was found in some regions, such as in its northern portion. Land use policies should consider regional infrastructural and participative governance potentialities. The results suggests possible areas where joint agricultural activities and human presence may be favourable for biodiversity conservation.

scholarly journals Using Electronic Medical Record Data to Better Understand Obesity in Hispanic Neighborhoods in El Paso, Texas

2020 ◽  
Vol 17 (12) ◽  
pp. 4591
Author(s):  
Jennifer Salinas ◽  
Jon Sheen ◽  
Malcolm Carlyle ◽  
Navkiran Shokar ◽  
Gerardo Vazquez ◽  
...  
Keyword(s):  
Hot Spot ◽  
El Paso ◽  
Delayed Diagnosis ◽  
Positive Association ◽  
The United States ◽  
Median Income ◽  
Obesity Prevalence ◽  
Ethnic Concentration ◽  
Prevalence Of Obesity ◽  
El Paso County

The prevalence of obesity has been persistent amongst Hispanics over the last 20 years. Socioeconomic inequities have led to delayed diagnosis and treatment of chronic medical conditions related to obesity. Factors contributing include lack of insurance and insufficient health education. It is well-documented that obesity amongst Hispanics is higher in comparison to non-Hispanics, but it is not well-understood how the socioeconomic context along with Hispanic ethnic concentration impact the prevalence of obesity within a community. Specifically studying obesity within Hispanic dominant regions of the United States, along the Texas–Mexico border will aid in understanding this relationship. El Paso, Texas is predominantly Mexican-origin Hispanic, making up 83% of the county’s total population. Through the use of electronic medical records, BMI averages along with obesity prevalence were analyzed for 161 census tracts in the El Paso County. Geographic weighted regression and Hot Spot technology were used to analyze the data. This study did identify a positive association between Hispanic ethnic concentration and obesity prevalence within the El Paso County. Median income did have a direct effect on obesity prevalence while evidence demonstrates that higher education is protective for health.

scholarly journals Higher evolutionary rates in life-history traits in insular than in mainland palms

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Cibele Cássia-Silva ◽  
Cíntia G. Freitas ◽  
Larissa Pereira Lemes ◽  
Gustavo Brant Paterno ◽  
Priscila A. Dias ◽  
...  
Keyword(s):  
Life History ◽  
Adaptive Radiation ◽  
Life History Traits ◽  
Fruit Size ◽  
Habitat Type ◽  
Taxonomic Diversity ◽  
Evolutionary Rates ◽  
Volcanic Island ◽  
Optimal Value ◽  
Volcanic Islands

AbstractIsolated islands, due to the reduced interspecific competition compared to mainland habitats, present ecological opportunities for colonizing lineages. As a consequence, island lineages may be expected to experience higher rates of trait evolution than mainland lineages. However, island effects on key life-history traits of vascular plants remain underexplored at broad spatiotemporal scales, even for emblematic island clades such as palms. Here, we used phylogenetic comparative methods to evaluate potential differences in size and macroevolutionary patterns of height and fruit diameter among mainland, continental, and volcanic island palms. Further, phylogenetic beta-diversity was used to determine if lineage turnover supported an adaptive radiation scenario on volcanic islands. Volcanic island palms were taller than their continental island and mainland counterparts, whereas continental island palms exhibited smaller fruit size. Height and fruit size of palms evolved under evolutionary constraints towards an optimal value. However, scenarios of adaptive radiation and niche conservatism were not supported for the height and fruit size of volcanic and mainland palm clades, respectively, as expected. Instead, continental island palms exhibited higher evolutionary rates for height and fruit size. Insular palm assemblages (continental and volcanic) are composed of unique lineages. Beyond representing evolutionary sources of new palm lineages, our results demonstrate that insular habitats are important in shaping palm trait diversity. Also, the higher phenotypic evolutionary rates of continental island palms suggest disparate selection pressures on this habitat type, which can be an important driver of trait diversification over time. Taken together, these results stress the importance of insular habitats for conservation of functional, phylogenetic, and taxonomic diversity of palms.

scholarly journals Predicting suitable habitat of the Chinese monal (Lophophorus lhuysii) using ecological niche modeling in the Qionglai Mountains, China

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3477 ◽  
Author(s):  
Bin Wang ◽  
Yu Xu ◽  
Jianghong Ran
Keyword(s):  
Ecological Niche ◽  
Wildlife Conservation ◽  
Ad Hoc ◽  
Ecological Niche Modeling ◽  
Niche Modeling ◽  
Maximum Temperature ◽  
Suitable Habitat ◽  
Natural Habitats ◽  
Dispersal Capacity ◽  
Suitable Habitats

Understanding the distribution and the extent of suitable habitats is crucial for wildlife conservation and management. Knowledge is limited regarding the natural habitats of the Chinese monal (Lophophorus lhuysii), which is a vulnerable Galliform species endemic to the high-montane areas of southwest China and a good candidate for being an umbrella species in the Qionglai Mountains. Using ecological niche modeling, we predicted current potential suitable habitats for the Chinese monal in the Qionglai Mountains with 64 presence points collected between 2005 and 2015. Suitable habitats of the Chinese monal were associated with about 31 mm precipitation of the driest quarter, about 15 °C of maximum temperature of the warmest month, and far from the nearest human residential locations (>5,000 m). The predicted suitable habitats of the Chinese monal covered an area of 2,490 km2, approximately 9.48% of the Qionglai Mountains, and was highly fragmented. 54.78% of the suitable habitats were under the protection of existing nature reserves and two conservation gaps were found. Based on these results, we provide four suggestions for the conservation management of the Chinese monal: (1) ad hoc surveys targeting potential suitable habitats to determine species occurrence, (2) more ecological studies regarding its dispersal capacity, (3) establishment of more corridors and green bridges across roads for facilitating species movement or dispersal, and (4) minimization of local disturbances.

Applying opportunistic observations to model current and future suitability of the Kopet Dagh Mountains for a Near Threatened avian scavenger

2020 ◽  
pp. 175815592096275
Author(s):  
Sayyad Sheykhi Ilanloo ◽  
Ali Khani ◽  
Anooshe Kafash ◽  
Negin Valizadegan ◽  
Sohrab Ashrafi ◽  
...  
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
Anthropogenic Activities ◽  
Future Climate Change ◽  
Natural Habitats ◽  
Bearded Vulture ◽  
The Future ◽  
Suitable Habitats ◽  
Kopet Dagh ◽  
Near Threatened

Many avian species are in danger of extinction due to anthropogenic activities and climate change. Human activities have led to eradication of many natural habitats and climate change has altered species distribution especially in mountainous habitats. In the present study, we used distribution records of a Near Threatened avian scavenger, bearded vulture ( Gypaetus barbatus) that were collected through 9 years of opportunistic observations and modeled its distribution in the Khorasane-Razavi Province in Iran. We also assessed the impacts of future climate change on the distribution of this species. Our results show that most suitable habitats for Bearded vultures are in the northern regions of the Khorasan-e-Razavi province. The most important variables affecting the distribution of the bearded vulture were the annual precipitation (37.5% contribution), landcover (22% contribution), and distance to road (16.2% contribution). Our results also showed that around 80% to 91% of the species’ suitable habitats will decrease due to climate change in the future. Suitable habitats of the species that are predicted to remain suitable in the future should be prioritized for conservation. Human activities like road expansion should be avoided in areas with high suitability for this species. This study stresses the need for action to conserve this vulture in the Khorasan-e-Razavi province, and beyond its borders.

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