Urban Sprawl, Food Subsidies and Power Lines: An Ecological Trap for Large Frugivorous Bats in Sri Lanka?

Electrocution is one of the less known anthropogenic impacts likely affecting the bat population. We surveyed 925 km of overhead distribution power lines that supply energy to spreading urbanized areas in Sri Lanka, recording 300 electrocuted Indian flying foxes (Pteropus giganteus). Electrocutions were recorded up to 58 km from the nearest known colony, and all of them were in urbanized areas and very close ( X ¯ = 4.8 m) to the exotic fruiting trees cultivated in gardens. Predictable anthropogenic food subsidies, in the form of cultivated fruits and flowers, seem to attract flying foxes to urban habitats, which in turn become ecological traps given their high electrocution risk. However, electrocution rates greatly varied among the 352 power lines surveyed (0.00–24.6 indiv./km), being highest in power lines with four wires oriented vertically ( X ¯ = 0.92 indiv./km) and almost zero in power lines with wires oriented horizontally. Therefore, the latter design should be applied to projected new power lines and old vertically oriented lines in electrocution hotspots should be substituted. Given that flying foxes are key seed dispersers and pollinators, their foraging habitat selection change toward urban habitats together with high electrocution risk not only may contribute to their population decline but also put their ecosystem services at risk.

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Faculty Opinions recommendation of Lyssavirus in indian flying foxes, sri lanka.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.727277684.793528349 ◽

2017 ◽

Author(s):

Charles Rupprecht

Keyword(s):

Sri Lanka ◽

Flying Foxes

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Using intrinsic vulnerability and anthropogenic impacts to evaluate and compare groundwater risk potential at northwestern and western coastal aquifers of Sri Lanka through coupling DRASTIC and GIS approach

Applied Water Science ◽

10.1007/s13201-021-01452-y ◽

2021 ◽

Vol 11 (7) ◽

Author(s):

Ratha Phok ◽

Nandalal Kosgallana Duwage Wasantha ◽

Weerakoon Sumana Bandara ◽

Pitawala Herath Mudiyanselage Thalapitiye Ge ◽

Dharmagunawardhane Hingure Arachchilage

Keyword(s):

Sri Lanka ◽

Groundwater Contamination ◽

Anthropogenic Impacts ◽

Shallow Groundwater ◽

Monitoring Network ◽

Groundwater Vulnerability ◽

Moderate Risk ◽

Pollution Risk ◽

Intrinsic Vulnerability ◽

Contamination Risk

AbstractGroundwater vulnerability assessment has become a crucial step in successfully protecting groundwater against pollution. An attempt of this study has been made to evaluate groundwater contamination risk using intrinsic vulnerability and land-uses in Vanathavillu, Kalpitiya and Katana area in Sri Lanka, using coupled DRASTIC with GIS as feasible methodology. The findings reveal that the groundwater in the areas under study falls under very low to high contamination risk. The higher risk of contamination has been identified in most of the Kalpitiya (about 82%) with the moderate along the beach in the west and next to Puttalam lagoon in the northeast and southeast. This is mainly due to pollution risk inherent with intense vegetable cultivation, over pumping, shallow groundwater tables and permeable sandy soil. Vanathavillu is under very low to moderate contamination risk, in which the moderate risk (about 13%) has especially been found the center, central southwest and west of the area. The relative less deep groundwater tables, possible seepage from the underlying limestone aquifer and less permeable red earth soil could be cause for the moderate risk in the area. Furthermore, results show that the Katana has low to moderately high groundwater contamination risk. Nitrate has a good agreement with the different pollution risk classes and that nitrate can be used as an indicator of aquifer degradation inherent with land-use activities in the coastal areas. Groundwater quality monitoring network should be set up to minimize the anthropogenic acts, particularly in high and moderate contamination risk zones.

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Selection of foraging habitat and diet of the Hoopoe Upupa epops in the mosaic-like cultural landscape of Goričko (NE Slovenia)

Acrocephalus ◽

10.1515/acro-2015-0008 ◽

2015 ◽

Vol 36 (166-167) ◽

pp. 109-132

Author(s):

Mojca Podletnik ◽

Damijan Denac

Keyword(s):

Home Range ◽

Agricultural Landscape ◽

Population Decline ◽

Home Range Size ◽

Range Size ◽

Foraging Habitat ◽

Convex Polygons ◽

Upupa Epops ◽

Mole Crickets ◽

Selection Of

In 2012 and 2013, the selection of foraging habitats and the diet of the Hoopoe Upupa epops were studied in the Goričko area, where a significant population decline of the species has been recorded in the past 15 years. Goričko is an area with a well-preserved traditional mosaic-like agricultural landscape very rich in biodiversity which, however, is disappearing. The diet was determined using automatic camera recordings of prey brought to chicks by parents. Mole crickets Gryllotalpa gryllotalpa were the most dominant prey (35.4% frequency and 81.3% biomass of prey), followed by Scarab beetles larvae Scarabaeidae, caterpillars Lepidoptera larvae and True flies Diptera. Feeding frequency was highest in the period of most intensive chick growth (between 8 and 21 days of age). Selection of foraging habitat was researched by observation of birds during foraging. Hoopoes foraged mostly in mown meadows and grassy courtyards and, to a lesser extent, on sandy cart tracks and road edges. These habitats were characterized by low vegetation and patches of bare ground that enabled Hoopoes to forage efficiently. Home range size was determined using minimum convex polygons. The maximum home range size was between 42.9 and 57.7 ha, while the percentage of foraging habitats within the home range did not exceed 18%. Based on our results, we propose the following measures for effective Hoopoe conservation in the area: maintaining the present range of existing unimproved meadows, stopping the conversion of meadows into fields, restoring fields to meadows, prohibiting the use of pesticides targeting Mole crickets.

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A demographic framework for the adaptive management of the endangered arid-zone tree species Acacia peuce

Australian Journal of Botany ◽

10.1071/bt12221 ◽

2013 ◽

Vol 61 (2) ◽

pp. 89 ◽

Cited By ~ 3

Author(s):

S. Raghu ◽

Catherine E. M. Nano ◽

Chris R. Pavey

Keyword(s):

Tree Species ◽

Arid Zone ◽

Anthropogenic Impacts ◽

Population Decline ◽

Extreme Rainfall ◽

Vital Rates ◽

Matrix Population Models ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Slow Growing

Slow-growing desert tree species pose unique conservation challenges; their demography is driven by rare stochastic climatic events, remoteness of populations makes monitoring difficult and, consequently, their management is often information-limited. In particular, the paucity of information on vital rates at a relevant temporal scale makes analyses of demography and population viability difficult. Our objective was to undertake a demographic analysis of the threatened arid-zone tree species (Acacia peuce F.Muell.) that is a model system in terms of being (1) a slow-growing desert tree species whose recruitment is limited to stochastic and rare extreme rainfall events, and (2) a species of conservation significance growing in a remote location where remoteness imposes limitations on conservation monitoring. Complementary analyses using pattern- and process-derived matrix population models, based on a dataset derived from a 30-year monitoring effort, verified that the smallest of the A. peuce populations would continue to grow under current environmental conditions. Population growth in this species is most influenced by the survival or adult and sapling stages. Stochastic demographic simulations revealed that climate change is likely to significantly elevate the risk of population decline, particularly in fragment stands. The long-term viability of A. peuce hinges on sustaining the survival rates of adult and sapling stages by managing stresses to individuals in these stages, and through minimising anthropogenic disturbance to populations during rare, stochastic and extreme rainfall events that trigger recruitment. Extending the current non-binding agreement enabling the use of fences to exclude cattle, and improved interpretative signage to raise awareness of anthropogenic impacts on this species will significantly aid conservation of this species. The integration of modelling, monitoring, and management within a demographic framework can facilitate efficient and effective conservation of slow-growing arid-zone tree species, despite the challenges imposed by remoteness.

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Implications of forest management practices for sex-specific habitat use by Nycticeius humeralis

Journal of Mammalogy ◽

10.1093/jmammal/gyz088 ◽

2019 ◽

Vol 100 (4) ◽

pp. 1263-1273

Author(s):

Youngsang Kwon ◽

Anna C Doty ◽

Megan L Huffman ◽

Virginie Rolland ◽

Daniel R Istvanko ◽

...

Keyword(s):

Forest Management ◽

Habitat Use ◽

Vegetation Index ◽

Management Practices ◽

Anthropogenic Impacts ◽

Suitable Habitat ◽

Foraging Habitat ◽

Landscape Characteristics ◽

Wide Range ◽

Probability Of Presence

AbstractNorth American bats are experiencing declines in part due to anthropogenic impacts resulting in habitat loss and disturbance. In eastern deciduous forests, bats rely on forest resources for all or part of the year. Therefore, to promote conservation of bats, it is essential to determine whether current forest management techniques are compatible with habitat use by bats. We evaluated the relative effect of landscape characteristics, including forest management variables, on sex-specific foraging habitat of an insectivorous forest-dwelling bat species, the evening bat (Nycticeius humeralis), and predicted areas of suitable habitat for N. humeralis. A total of 18 variables were assessed using a maximum-entropy (Maxent) machine-learning approach: eight land use–land cover classes, three stand types, two topography measures, normalized difference vegetation index, and four forest management variables. Females showed the highest probability of presence closer to stands treated with prescribed fire, whereas males showed the highest probability of presence closer to reforested stands. In general, males exhibited more flexibility than females in their habitat selection. The Maxent model further indicated that habitat associated with suitability of > 70% was ~4 times larger for males than females, and predicted an additional area of suitable foraging habitat where no presence locations had been recorded. Our modeling approach may be suitable for other researchers to derive models appropriate for a wide range of bat species.

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Genetic analyses reveal limited dispersal and recovery potential in the large freshwater crayfish Euastacus armatus from the southern Murray–Darling Basin

Marine and Freshwater Research ◽

10.1071/mf16006 ◽

2017 ◽

Vol 68 (2) ◽

pp. 213 ◽

Cited By ~ 7

Author(s):

Nick S. Whiterod ◽

Sylvia Zukowski ◽

Martin Asmus ◽

Dean Gilligan ◽

Adam D. Miller

Keyword(s):

Gene Flow ◽

Anthropogenic Impacts ◽

Population Decline ◽

Biological Traits ◽

Freshwater Crayfish ◽

Freshwater Species ◽

Genetic Structuring ◽

Murray Darling Basin ◽

Murray River ◽

Dispersal Limitations

Understanding dispersal traits and adaptive potential is critically important when assessing the vulnerability of freshwater species in highly modified ecosystems. The present study investigates the population genetic structure of the Murray crayfish Euastacus armatus in the southern Murray–Darling Basin. This species has suffered significant population declines in sections of the Murray River in recent years, prompting the need for information on natural recruitment processes to help guide conservation. We assessed allele frequencies from 10 polymorphic microsatellite loci across 20 sites encompassing the majority of the species’ range. Low levels of gene flow were observed throughout hydrologically connected waterways, but significant spatial autocorrelation and low migration rate estimates reflect local genetic structuring and dispersal limitations, with home ranges limited to distances <50-km. Significant genetic differentiation of headwater populations upstream of barriers imposed by impoundments were also observed; however, population simulations demonstrate that these patterns likely reflect historical limitations to gene flow rather than contemporary anthropogenic impacts. Dispersal limitations, coupled with its biological traits, suggest that local populations are vulnerable to environmental disturbance with limited potential for natural recolonisation following population decline. We discuss the implications of these findings in the context of managing the recovery of the species.

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Population genomic, climatic and anthropogenic evidence suggest the role of human forces in endangerment of green peafowl ( Pavo muticus )

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2021.0073 ◽

2021 ◽

Vol 288 (1948) ◽

Author(s):

Feng Dong ◽

Hao-Chih Kuo ◽

Guo-Ling Chen ◽

Fei Wu ◽

Peng-Fei Shan ◽

...

Keyword(s):

Climate Change ◽

Human Disturbance ◽

Anthropogenic Impacts ◽

Critical Role ◽

Population Decline ◽

Genomic Diversity ◽

Integrative Approach ◽

Pavo Muticus ◽

Green Peafowl

Both anthropogenic impacts and historical climate change could contribute to population decline and species extinction, but their relative importance is still unclear. Emerging approaches based on genomic, climatic and anthropogenic data provide a promising analytical framework to address this question. This study applied such an integrative approach to examine potential drivers for the endangerment of the green peafowl ( Pavo muticus ). Several demographic reconstructions based on population genomes congruently retrieved a drastic population declination since the mid-Holocene. Furthermore, a comparison between historical and modern genomes suggested genetic diversity decrease during the last 50 years. However, climate-based ecological niche models predicted stationary general range during these periods and imply the little impact of climate change. Further analyses suggested that human disturbance intensities were negatively correlated with the green peafowl's effective population sizes and significantly associated with its survival status (extirpation or persistence). Archaeological and historical records corroborate the critical role of humans, leaving the footprint of low genomic diversity and high inbreeding in the survival populations. This study sheds light on the potential deep-time effects of human disturbance on species endangerment and offers a multi-evidential approach in examining underlying forces for population declines.

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The role of predation in the decline and extirpation of woodland caribou

10.26686/wgtn.12971864.v1 ◽

2020 ◽

Author(s):

Heiko Wittmer ◽

ARE Sinclair ◽

BN McLellan

Keyword(s):

Rangifer Tarandus ◽

Population Decline ◽

Temporal Distribution ◽

Pregnancy Rates ◽

Foraging Habitat ◽

Woodland Caribou ◽

Instantaneous Rate ◽

Population Growth Rates ◽

Rate Of Increase ◽

Winter Foraging

To select appropriate recovery strategies for endangered populations, we must understand the dynamics of small populations and distinguish between the possible causes that drive such populations to low numbers. It has been suggested that the pattern of population decline may be inversely density-dependent with population growth rates decreasing as populations become very small; however, empirical evidence of such accelerated declines at low densities is rare. Here we analyzed the pattern of decline of a threatened population of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada. Using information on the instantaneous rate of increase relative to caribou density in suitable winter foraging habitat, as well as on pregnancy rates and on causes and temporal distribution of mortalities from a sample of 349 radiocollared animals from 15 subpopulations, we tested 3 hypothesized causes of decline: (a) food regulation caused by loss of suitable winter foraging habitat, (b) predation-sensitive foraging caused by loss of suitable winter foraging habitat and (c) predation with caribou being secondary prey. Population sizes of caribou subpopulations ranged from <5 to >500 individuals. Our results showed that the rates of increase of these subpopulations varied from -0.1871 to 0.0496 with smaller subpopulations declining faster than larger subpopulations. Rates of increase were positively related to the density of caribou in suitable winter foraging habitat. Pregnancy rates averaged 92.4% ±2.24 and did not differ among subpopulations. In addition, we found predation to be the primary cause of mortality in 11 of 13 subpopulations with known causes of mortality and predation predominantly occurred during summer. These results are consistent with predictions that caribou subpopulations are declining as a consequence of increased predation. Recovery of these woodland caribou will thus require a multispecies perspective and an appreciation for the influence of inverse density dependence on population trajectories. © Springer-Verlag 2005.

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