Artificial Water Sources Research Articles

Improvement of water quality through coordinated multi-trophic level biomanipulations: Application to a subtropical emergency water supply lake

Artificial emergency water source lakes have been built in most cities in the middle and lower reaches of the Yangtze River, China, to ensure water safety for residents. However, these new ecosystems are prone to algal blooms or other degraded water quality conditions. A newly built water supply lake in the lower reaches of the Yangtze River was selected as a model system to test whether the coordinated manipulation of fish and submerged macrophyte communities could enhance ecosystem function and quality. The coordinated manipulations spanned a five-year period, aiming to enhance both top-down and bottom-up control of phytoplankton. As a result of these manipulations, the catch per unit effort of small-bodied zooplanktivorous fishes decreased by >95 % from year two and remained low. The coverage and biomass of submerged macrophytes increased year by year. Water transparency increased from 1.07 to 3.33 m. Total phosphorus and total nitrogen showed a decreasing trend (not significant though). The annual mean biomass of Cyanophyta, Chlorophyta and Bacillariophyta decreased from 2.99 to 0.03 mg/L, 3.90 to 0.16 mg/L, and 3.50 to 0.3 mg/L, respectively. The biomass of phytoplankton in different groups decreased in all four seasons. The annual mean biomass of Cladocera and Copepoda remained low. The biomass of Cladocera and Copepoda decreased in summer, fall, and winter. The Ecosystem Health Index - increased from 15.9 to 32.0. The pros and cons of the various top-down and bottom-up control measures employed are discussed. This research presents a valuable case study on the enhancement of ecosystem structure and function in newly constructed emergency water supply lakes and offers insights into the restoration of other subtropical shallow lakes.

Mammal diversity responses to anthropic, environmental, and seasonal changes within Caatinga seasonal dry forest landscapes

AbstractCaatinga's conservation and biodiversity are threatened due to the intensification of anthropic activities and climate change. The mammals have different responses to seasonal and anthropic changes, however particularly in Caatinga, these effects are still poorly understood. We assessed the influence of anthropic (distance from urban areas and wind farms), environmental (distance from water), and seasonal (Normalized Difference Vegetation Index (NDVI) and land surface temperature (LST)) variables on the number of records and richness of medium and large‐sized mammals in Brazilian Caatinga. We used camera traps in 2016–2017 and 2018–2019, estimated the variation (cv) of NDVI and LST, and generated Euclidean distance maps to anthropic and environmental variables at 250, 500, and 1000 m spatial scales. We performed Generalized Linear Models, used the Akaike information criterion, and calculated model averaging to assess the strength and direction of effect and the uncertainties of the winner models, respectively. The distance from wind farms and maximum LST had a noticeable effect on the number of records and total richness. The distance from wind farms had a negative effect on the records of Dicotyles tajacu and a positive effect on the records of Leopardus pardalis and richness. The maximum LST had a negative effect on the records of L. pardalis and a positive effect on the records of Puma concolor and Cerdocyon thous. Our results emphasize that an unsustainable expansion of wind farms is likely to compromise mammal diversity. We found an opposite pattern for some species regarding LST. However, it is important to highlight that the conservation of vegetation areas on the top of mountains and springs, and the installation of artificial water sources are important strategies to mitigate the impacts of high temperatures on mammals' biodiversity in Caatinga.Abstract in Portuguese is available with online material.

Genetic Diversity of Legionella pneumophila Isolates from Artificial Water Sources in Brazil

Legionella pneumophila (Lp) is a Gram-negative bacterium found in natural and artificial aquatic environments and inhalation of contaminated aerosols can cause severe pneumonia known as Legionnaires’ Disease (LD). In Brazil there is hardly any information about this pathogen, so we studied the genetic variation of forty Legionella spp. isolates obtained from hotels, malls, laboratories, retail centers, and companies after culturing in BCYE medium. These isolates were collected from various sources in nine Brazilian states. Molecular identification of the samples was carried out using Sequence-Based Typing (SBT), which consists of sequencing and analysis of seven genes (flaA, pilE, asd, mip, mompS, proA, and neuA) to define a Sequence Type (ST). Eleven STs were identified among 34/40 isolates, of which eight have been previously described (ST1, ST80, ST152, ST242, ST664, ST1185, ST1464, ST1642) and three were new STs (ST2960, ST2962, and ST2963), the former identified in five different cooling towers in the city of São Paulo. The ST1 that is widely distributed in many countries was also the most prevalent in this study. In addition, other STs that we observed have also been associated with legionellosis in other countries, reinforcing the potential of these isolates to cause LD in Brazil. Unfortunately, no human isolates could be characterized until presently, but our observations strongly suggest the need of surveillance implementation system and control measures of Legionella spp. in Brazil, including the use of more sensitive genotyping procedures besides ST.

Operation and Performance of The Lab and Pilotscale Greywater Treatment Systems: Biochar and Gravel Use in South Africa

Water security in South Africa depends on natural and artificial water sources such as rivers, lakes, rainwater harvesting, boreholes, dams, desalination, the importation of water from nearby countries, and wastewater treatment plants. The primary input to these water resources is rainfall which is estimated to be around 492 mm per year and is half of the world average (985 mm per year) due to climate change impacts. This study encourages the treatment and reuse of greywater as an additional water source for non-potable purposes such as toilet flushing and irrigation. The performance of the Laboratory (Lab)-scale Gravel Filter Towers (GFTs) was evaluated concurrently with the Pilot-scale system for remediation of the microbiological and physicochemical constituents in greywater which was sampled from separate single-households for both systems. The highest removal efficiency of faecal coliforms by the GTFs was 92.89 ± 93.39 % while the Pilot-scale exhibited a removal efficiency of 21.51 ± 12.47 %. The systems showed partial removal of microbiological, chemical, nutrient, and physical constituents, indicating that further analysis and improvements are required before decentralization. The GFTs could be improved by the addition of a biochar filter while the pilot-scale systems require fresh treatment materials monthly to avoid clogging and leaching of biofilms to the final collection tank. Further analysis could involve the profiling of the microbial communities using metagenomic techniques which may provide insight into the biochemical functioning (bioremediation, quorum sensing, and pathogenicity) of the system.

Persistent long-term habitat use by Florida manatees at Fort Pierce, Florida from 1997 to 2020.

To survive cold winters, Florida manatees (Trichechus manatus latirostris) depend on artificial (i.e., power plants) and natural warm water sources such as springs and passive thermal basins. Passive thermal basins can provide critical habitat for manatees for short or extended periods of time. The Henry D. King Powerplant in Fort Pierce, Florida discharged warm water into Moore's Creek until it went offline in 1995. However, it is unknown to what degree manatees continue to occupy this area and how environmental factors influence their occurrence in the creek. To explore this, we examined the habitat use of Florida manatees in Moore's Creek after the shutdown from November 1997 to March 2020 from daily counts of manatees. In addition, we correlated local environmental data (ambient air, temperature, salinity) to assess if Moore's Creek had properties indicative of a passive thermal basin. Results indicated there was not an increase or decrease in habitat use over twenty years in the Creek. The consistent use of Moore's Creek over the study period suggests that this habitat possesses thermal and freshwater resources to support manatee occurrence long-term. These findings provide robust support for the importance of this habitat and passive thermal basins for Florida manatees.

Use of wildlife-friendly structures in residential gardens by animal wildlife: evidence from citizen scientists in a global biodiversity hotspot

Private gardens comprise a large component of greenspace in cities and can offer substantial conservation opportunities. There has been strong advocacy from researchers, policymakers, and conservation practitioners to engage householders in wildlife-friendly gardening practices to increase the quantity, quality and connection of habitat resources for urban wildlife. Despite this call to action, there remains limited knowledge on the use and benefit of some wildlife-friendly structures within gardens, such as artificial refuges and water sources. In collaboration with 131 citizen scientists in southwestern Australia, we examined the use of seven wildlife-friendly structure types by four vertebrate taxa groups. Following 2841 wildlife surveys undertaken between 31 July 2022 and 22 February 2023, we found that all structures were used primarily by target taxa, water sources were often used by relatively common species, certain structures such as possum shelters were used by rare and threatened species (e.g. western ringtail possum), and that there was evidence of animals making use of the wildlife-friendly structures for reproduction (e.g. bird eggs in nest boxes and tadpoles in water sources). Water sources were used more frequently and by a greater diversity of wildlife than artificial refuges. In particular, bird baths were used by the highest number of species (mainly birds) while ponds were used by the greatest variety of taxa (birds, reptiles, frogs, mammals). Our findings provide evidence-based support for the advocacy of wildlife-friendly gardening practices and further highlight the role of residential gardens for biodiversity conservation.

Spatial-temporal characteristics of more than 50,000 wildfires in Japan from 1995 to 2020

The spatial-temporal characteristics of wildfires were summarized based on fire reports covering 55,863 wildfires with a total burned area of 289.91 km2 from 1995 to 2020 in Japan. The long-term decreasing trend was largely influenced by changes in social aspects, while the annual fluctuation was determined by large-scale events. The wildfire season started around early January in the southern part and gradually shifted northward over approximately three months. A total of 98.77% of cases were human-induced, and 1.23% were caused by lightning. Regarding response time after receiving the call, firefighting was started within 30 min in 89% of cases and controlled within 1 h in 85% of cases, where spatial characteristics were insignificant. Full-time fire departments utilized artificial water sources primarily in 72% of cases and natural water sources in 28%, while the rate using natural water sources increased as the burned area increased. Natural water sources from ponds and rivers exhibited regionalities. Cluster analysis revealed five wildfire regions reflecting natural and anthropogenic factors. Furthermore, the Mann–Kendall trend test concluded that the initiation process decreased almost uniformly across the country, while regional differences existed regarding the expansion process. Additionally, only human-induced wildfires had a significant decreasing trend.

The use of swimming pools by bats on a game reserve in South Africa

AbstractWhile the use of anthropogenic resources by wildlife in degraded habitats has been frequently documented, the use of such alternative resources in natural and semi‐natural habitats is not yet well understood. We explored the use of artificial water sources by bats in a semi‐natural habitat by conducting acoustic monitoring surveys at swimming pools on Amakhala Game Reserve in the Eastern Cape of South Africa from 2018 to 2020. We identified 7 of 23 local species in 24,909 recorded activities associated with resource use at the swimming pools, including 1,374 feeding buzzes and 9,286 drinking buzzes. This study confirmed that bats were using swimming pools in the game reserve as a foraging and drinking resource and indicates that such anthropogenic features could be of value to bats and potentially other wildlife in natural and semi‐natural habitats.

Insights into the habitat associations, phylogeny, and diet of Pipistrellus maderensis in Porto Santo, northeastern Macaronesia

Abstract. Around 60 % of all bat species occur in islands, and nearly one in four is an insular endemic. Bats are often the only native terrestrial mammals in oceanic islands, and despite increasing anthropogenic pressures, little is known about the distribution, natural history, and population status of most insular bat populations. The sub-tropical archipelago of Madeira is composed of the volcanic islands of Madeira, Porto Santo, and Desertas and is home to the Macaronesian endemic Pipistrellus maderensis, to the endemic subspecies Nyctalus leisleri verrucosus, and to Plecotus austriacus. Pipistrellus maderensis is known to both Madeira and Porto Santo, whereas the other two species have only been recorded in the former. However, no bats have been recorded in Porto Santo for over 15 years, raising fears that bats are probably extinct in the island. In July 2021, we conducted an island-wide acoustic survey using AudioMoth passive acoustic recorders, leading to the detection of Pipistrellus maderensis in 28 out of the 46 sampling sites (60 %). The species' activity was strongly associated with artificial water sources, and genetic samples from six captured individuals revealed that the populations of Pipistrellus maderensis in Porto Santo and Madeira have a close phylogenetic affinity. Furthermore, using DNA metabarcoding, we found that the species feeds on a wide variety of insects, including several economically important pest species and disease vectors. These findings emphasise the need to target more conservation and research efforts towards extant island bat populations and the potential ecosystem services they provide.

Domestic water versus imported virtual blue water for agricultural production: A comparison based on energy consumption and related greenhouse gas emissions

AbstractThe supply of water, food, and energy in our global economy is highly interlinked. Virtual blue water embedded into internationally traded food crops has therefore been extensively researched in recent years. This study focuses on the often neglected energy needed to supply this blue irrigation water. It provides a globally applicable and spatially explicit approach to the watershed level for water source specific quantification of energy consumption and related greenhouse gas (GHG) emissions of irrigation water supply. The approach is applied to Israel's total domestic and imported food crop supply of 105 crops by additionally including import‐related transportation energy and emissions. Total energy use and related emissions of domestic crop production were much lower (551 GWh/422 kt CO2‐equivalents [CO2e]) than those embedded into crop imports (1639 GWh/649 kt CO2e). Domestic energy and emissions were mainly attributable to the irrigation water supply with artificial water sources (treated domestic wastewater and desalinated water, 84%). Transport accounted for 79% and 66% of virtually imported energy and emissions, respectively. Despite transport, specific GHG emissions (CO2e per ton of crop) were significantly lower for several crops (e.g., olives, almonds, chickpeas) compared to domestic production. This could be attributed to the high share of energy‐intensive artificial water supply in combination with higher irrigation water demands in Israel. In the course of an increasing demand for artificial water supply in arid and semi‐arid regions, our findings point to the importance of including “energy for water” into comparative environmental assessment of crop supply to support decision‐making related to the water–energy–food nexus.

Жамбыл облысының микрогидронимдерін зерттеудегі жасанды және табиғи су көздері атауларының көрінісі

A large number of natural and artificial water sources are found on the territory of Zhambyl region. This is due to the fact that in the territory located in the mountainous region, the names of rivers, lakes, streams, wells with rich reserves of water resources are often found, and the nature of hydrological objects is clearly indicated. It can be said that the terms defining geographical names that characterize natural water sources have an ecological and geographical basis. Natural water sources have played an important role in the economy and provide extensive geographical information from history. From modern historical and archaeological data it can be seen that the first human settlements were located near water bodies. The article analyzes specific data on the manifestations, formation and features of the names of artificial and natural water sources in the study of microhydrogems of the Zhambyl region. The names of water bodies (hydronyms) are based on hydrographic terms. With the help of the terms contained in the hydronyms, it is possible to determine the type, nature and geographical features of water bodies. Toponymic analysis, geoinformation methods of differentiation and drawing conclusions were used in the study of microhydronyms of Zhambyl region.

Use of Human Dominated Landscape as Connectivity Corridors among Fragmented Habitats for Wild Asian Elephants (Elephas maximus) in the Eastern Part of Thailand

Habitat fragmentation due to human activities creates threats to wild Asian elephants (Elephas maximus) and increases human-elephant conflicts (HEC). This study analyzed connectivity maps among the core habitats of wild elephants in the eastern part of Thailand. Resistance surfaces, associated with geographic and land use features, were used to estimate the dispersal of wild elephants. An increase in roads, reservoirs, and agricultural areas in 2020 was noted. In addition, the increase of artificial water sources and roads has increased HEC. To reduce HEC, the study of suitable landscape corridors for wild Asian elephants can guide the development of effective connectivity among the habitat patches. The scattered locations of reserved forests induce wild elephants to enter agricultural areas. In 2020, during the dry season, wild elephants used 3552 habitat patches, 253 population patches (4875 km2), 8 breeding patches (68.1 km2), and 253 other patches (193.9 km2). However, habitat patches were reduced to 1961 patches (3850.9 km2) in the wet season. The 16 suitable corridors were recommended for connecting the finest wild Asian elephants. These suitable corridors can be used as a guideline to construct effective landscape corridors for wild Asian elephants’ movement among the habitat patches. This finding can help the local managers and villagers incorporate and design restoration areas for the movement and survival of wild Asian elephants and develop suitable areas for agricultural purposes.

Does water availability shift dietary preferences of coyotes in the west desert of Utah?

Water is one of the most essential resources on the planet and shapes entire ecosystems. Across the western United States, thousands of artificial water sources have been installed to assist wildlife populations in arid environments. It has been reported that kit foxes (Vulpes macrotis) can live independently of free-drinking water, but coyotes (Canis latrans) would have to more than triple their intake of prey biomass to meet energy requirements. However, previous researchers discovered no change in coyote space use, nor were survival rates of coyotes influenced by the removal of water sources. We predicted coyote diets in the treatment areas (i.e., water removed) would show an increase in leporids, as a source of preformed water after the water removal to compensate for the lack of free water. However, we found no evidence of a dietary shift by coyotes towards large-bodied prey (i.e., leporids) after water sources were removed; occurrence of leporids in the coyote diet decreased after water removal in both the control and treatment areas. Based on this study and previous research in Utah's west desert, coyotes in the Great Basin ecosystem were not influenced by artificial water sources in a spatial, demographic, or dietary capacity.

Gazelle–livestock interactions and impact of water resource development in the Ouadi Rimé–Ouadi Achim Reserve, Chad

AbstractThe Ouadi Rimé–Ouadi Achim Reserve (Réserve de l'Ouadi Rimé–Ouadi Achim) in central Chad supports large numbers of livestock and rare antelopes, and is the site of ongoing reintroductions of the scimitar-horned oryxOryx dammahand addaxAddax nasomaculatus. We present results of surveys conducted during 2011–2019 to examine patterns of relative abundance and distribution of dorcas gazellesGazella dorcas, dama gazellesNanger damaand livestock in relation to each other and to water sources in a 3,500 km2area in the centre of the Reserve. Dorcas gazelles numbered 7,700–18,000, moving extensively across the area. Livestock varied between c. 2,000 and 68,000 tropical livestock units across surveys, with density doubling in the wet season. Dorcas gazelle distribution was negatively associated with livestock, and livestock density was positively associated with artificial water sources. Dorcas gazelle densities were positively associated with locations where there had been wild fires in the 6 months prior to a survey. Dama gazelles were encountered only 13 times, insufficient to estimate their population size reliably. Opportunistic observations suggest dama gazelles avoid livestock and burnt ground. Our findings highlight the importance of the Reserve. We recommend the designation of a large, well-managed conservation priority zone in the Reserve's core area in which no further development of water resources is permitted. Management of livestock numbers within this zone at or below current levels is essential to integrate national goals for both biodiversity conservation and pastoralism development.

Pathways for avian influenza virus spread: GPS reveals wild waterfowl in commercial livestock facilities and connectivity with the natural wetland landscape.

Zoonotic diseases are of considerable concern to the human population and viruses such as avian influenza (AIV) threaten food security, wildlife conservation and human health. Wild waterfowl and the natural wetlands they use are known AIV reservoirs, with birds capable of virus transmission to domestic poultry populations. While infection risk models have linked migration routes and AIV outbreaks, there is a limited understanding of wild waterfowl presence on commercial livestock facilities, and movement patterns linked to natural wetlands. We documented 11 wild waterfowl (three Anatidae species) in or near eight commercial livestock facilities in Washington and California with GPS telemetry data. Wild ducks used dairy and beef cattle feed lots and facility retention ponds during both day and night suggesting use for roosting and foraging. Two individuals (single locations) were observed inside poultry facility boundaries while using nearby wetlands. Ducks demonstrated high site fidelity, returning to the same areas of habitats (at livestock facilities and nearby wetlands), across months or years, showed strong connectivity with surrounding wetlands, and arrived from wetlands up to 1251km away in the week prior. Telemetry data provides substantial advantages over observational data, allowing assessment of individual movement behaviour and wetland connectivity that has significant implications for outbreak management. Telemetry improves our understanding of risk factors for waterfowl-livestock virus transmission and helps identify factors associated with coincident space use at the wild waterfowl-domestic livestock interface. Our research suggests that even relatively small or isolated natural and artificial water or food sources in/near facilities increases the likelihood of attracting waterfowl, which has important consequences for managers attempting to minimize or prevent AIV outbreaks. Use and interpretation of telemetry data, especially in near-real-time, could provide key information for reducing virus transmission risk between waterfowl and livestock, improving protective barriers between wild and domestic species, and abating outbreaks.

Water-seeking behavior among terrestrial arthropods and mollusks in a cool mesic region: Spatial and temporal patterns.

Dehydration can have negative effects on animal physiological performance, growth, reproduction, and survival, and most animals seek to minimize these effects by reducing water losses or seeking water sources. Much—but not all—of the research on animal water balance comes from dryland ecosystems. However, animals inhabiting mesic regions may also experience desiccating conditions, for example within urban heat islands or during heatwaves and droughts. Here we examined how spatial variation in impervious surface and spatial and temporal variation in microclimate impact water demand behavior of terrestrial arthropods and mollusks in three areas of mesic Northwest Ohio, with analysis of taxa that exhibited the greatest water demand behavior. Water demand behavior was measured as the frequency that individuals were observed at an artificial water source (a moistened pouch), relative to the frequency at a control (a dry pouch). Overall, terrestrial arthropods and mollusks were found about twice as often at the water source than at the control (equivalent to 86 more observations on the wet pouch than on dry at each site, on average), with ants accounting for over 50% of the overall response in urban areas. Daily fluctuations in vapor pressure deficit (VPD) best predicted daily variation in water demand behavior, with increased demand at higher VPD. Mean VPD was generally highest near urbanized areas, but effects of VPD on water demand behavior were generally lower in urbanized areas (possibly related to reductions in overall abundance reducing the potential response). On certain days, VPD was high in natural areas and greenspaces, and this coincided with the highest arthropod water demand behavior observed. Our results suggest that terrestrial arthropod communities do experience periods of water demand within mesic regions, including in greenspaces outside cities, where they appear to respond strongly to short periods of dry conditions—an observation with potential relevance for understanding the effects of climate change.

Of irrigation canals and multifunctional agroforestry: Traditional agriculture facilitates Woolly-necked Stork breeding in a north Indian agricultural landscape

Conservation of biodiversity alongside agriculture is now a global priority. Tree-nesting waterbirds have a tenuous relationship with farmlands because their survival requires farmers to retain trees and wetlands amid croplands. Research on such birds is rare on tropical and sub-tropical agricultural landscapes where high human densities and intensive farming ostensibly deteriorate breeding conditions. We explored breeding ecology and nest site selection by the single-nesting Woolly-necked Stork (Ciconia episcopus) in Haryana, north India using 298 nests from 166 locations discovered between 2016 and 2020. We determined the relative strengths of association of nest locations with natural features (trees, wetlands), human presence (habitation) and artificial water sources (irrigation canals) to understand cues used by breeding storks to situate nests. Woolly-necked Stork brood size from 42 successful nests was relatively high (3.1 ± 0.9 SD), with nests close to human habitation and wetlands having smaller broods. Storks showed high nest site fidelity (44.5% of sites used > 1 year), rarely nested on man-made structures (electricity pylons; 8.4%), and distributed nests in a clumped pattern. Woolly-necked Storks situated nests ambivalent to natural features but associated strongly with man-made features (positively with irrigation canals; negatively with human habitation). Contrary to expectations, most nests were not on the tallest trees but on the medium sized, native Dalbergia sissoo though storks situated nests on two tall trees (native Ficus religiosa and exotic Eucalyptus sp.) far more than the trees’ availability. All three tree species were favoured either for traditional agroforestry or local religious beliefs. Traditional agriculture in Haryana supported a substantial breeding population of Woolly-necked Storks facilitated by agriculture-related components rather than existing natural features. This novel scenario contradicts conventional narratives that suggest multi-season small holder tropical and sub-tropical agriculture degrades breeding conditions for waterbirds. Our findings in Haryana reiterate the need to assemble a diverse conservation toolkit of different locally relevant mechanisms supporting biodiversity amid cultivation.

Spider monkey use of natural and artificial terrestrial water sources in Calakmul, Mexico

Abstract Geoffroy’s spider monkeys (Ateles geoffroyi) satisfy their need for water mainly from food items and arboreal water sources, but climate change and other anthropogenic impacts can drive a more frequent use of ground water by this arboreal species. Here, we report 25 events of use of natural and artificial terrestrial water bodies by spider monkeys recorded using camera-trapping in the Calakmul region, Mexico. Interestingly, these events occurred during the rainy season in locations where we did not record large predators and in most cases involved adult male individuals. These records suggest that habitat disruptions such as those associated with changing weather patterns and selective logging of large trees holding water reservoirs can lead to a greater use of terrestrial water sources by spider monkeys.

An avian dominance hierarchy at a supplemental water source in the Patagonian steppe.

Birds often compete and engage in interspecific agonistic interactions for access to resources such as food and breeding territories. Based on the observed outcomes from such interactions (i.e., patterns of displacements) dominance hierarchies can be established. Knowing which species can outcompete others for essential resources allows researchers to make predictions about the broader ecological impacts of interspecific interactions. We constructed an interspecific dominance hierarchy of twelve avian species which visited an artificial water source in an arid region of coastal Patagonia, Argentina. Displacements were categorized into four types, based on the behaviors involved in the interaction, and we tested if they could predict the difference in dominance between the interacting species (the difference between calculated dominance coefficients for the two focal species). Indirect displacements, involving only the arrival of the dominant species to the water source without direct aggression toward the subordinate bird, occurred more frequently between species with a large difference in dominance. The most dominant bird observed was the kelp gull (Larus dominicanus), which, due to an increasing population and expanding range, in part due to food supplementation from fisheries waste, is likely to outcompete terrestrial and marine avian species for other scarce resources.

CARACTERÍSTICAS DE AGUAJES ARTIFICIALES Y SU RELACIÓN CON EL USO POR LA FAUNA SILVESTRE EN COAHUILA, MÉXICO

Con el fin de proveer agua a las especies de fauna silvestre de interés cinegético, la construcción de aguajes artificiales inició en las décadas de 1940 y 1950 por agencias estatales y federales de los Estados Unidos. Sin embargo, para su construcción y establecimiento no se consideran todos los factores que incrementen su uso por la fauna silvestre. El objetivo de este estudio fue relacionar la frecuencia del uso de los aguajes artificiales por la fauna silvestre con sus características físicas, temperatura, humedad relativa del área, calidad del agua y características de la vegetación circundante a éstos en la UMA Rancho San Juan, Monclova, Coahuila, México. En este estudio, aunque se considera que la localidad del agua, la temperatura y humedad son importantes, las características de la vegetación aledaña a los aguajes, es la que más influye en su uso por la fauna silvestre. La frecuencia de uso de los aguajes por la fauna silvestre se registró con cámaras trampa (HC500 HyperFire Semi-Covert IR de Reconyx, Wisconsin, USA). Para conocer cuáles de las variables estudiadas se asociaron más con la frecuencia de visitas se realizó una prueba de coeficiente de regresión Poisson en el software R-Studio, y para una visualización gráfica de esta asociación se realizó un análisis de correspondencias múltiples en el software Xlstat. Las especies que más utilizaron los aguajes fueron venado cola blanca (Odocoileus virginianus, 32.8%), mapache (Procyon lotor, 18.9%) y pecarí (Pecari tajacu, 8.29%). De las 57 variables evaluadas, 11 se asociaron más con la frecuencia de visitas a los aguajes. El análisis de correspondencias múltiples identificó que el ancho del bordo de aguaje de 1 a 10 cm y la presencia frecuente de Vachellia farnesiana fueron las variables más relacionadas con la categoría de frecuencia de visitas alta. Estos resultados pueden ser utiles para entender mejor el uso de aguajes artificiales por la fauna silvestre y aumentar la probabilidad de su uso.