Decreasing reservoir water levels improve habitat quality for Asian elephants

Ranjeewa, Ashoka D.G.; Pastorini, Jennifer; Isler, Karin; Weerakoon, Dushni; Kottage, H; Fernando, Prithiviraj

doi:10.1016/j.mambio.2017.10.002

Cited by 10 publications

(6 citation statements)

References 39 publications

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“…This disparity may be partly explained by the lower mean AOO of elephants for the other Asian elephant range states (14.4 ± SD 13% of country area; Leimgruber et al, 2003). Compared to most range states, the greater extent of elephant range outside protected areas in Sri Lanka may be another contributory factor, as disturbed habitats support higher elephant densities (Fernando & Leimgruber, 2011; Pastorini et al, 2013; Evans et al, 2018; Ranjeewa et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

“…Habitats with an intermediate disturbance regime support higher densities of Asian elephants than undisturbed forests (Fernando & Leimgruber, 2011; Pastorini et al, 2013; Ranjeewa et al, 2018; Evans et al, 2018). In an analysis of Borneo elephant Elephas maximus borneensis ranging and habitat use, degraded and secondary forests were found to be of higher suitability for elephants than primary forests, but their value for elephant conservation is largely unappreciated (Evans et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

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First country-wide survey of the Endangered Asian elephant: towards better conservation and management in Sri Lanka

Fernando

Silva

Jayasinghe

et al. 2019

Oryx

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The Endangered Asian elephant Elephas maximus comes into widespread conflict with agrarian communities, necessitating active management. The species’ distribution is of primary importance for management planning. However, data-based countrywide distribution maps have not been available for any of the 13 Asian elephant range states. We conducted a 5 × 5 km grid-based questionnaire survey in Sri Lanka to produce an island-wide elephant distribution map. Elephants occur over 59.9% of Sri Lanka and people are resident in 69.4% of elephant range, indicating the challenge of separating people and elephants at a landscape scale. Elephants in Sri Lanka have lost 16.1% of their range since 1960 but their current distribution remains largely contiguous. We found the range of adult males was 15.1% greater, and less seasonal, than that of herds, possibly because males have a higher tolerance for conflict with people. The distribution of conflict coincided with the co-occurrence of humans and elephants. We conclude that a human–elephant coexistence model is the only viable option for effectively mitigating human–elephant conflict and conserving elephants in Sri Lanka. The findings are currently being used to effect a paradigm change in elephant conservation and management in the country.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

First country-wide survey of the Endangered Asian elephant: towards better conservation and management in Sri Lanka

Fernando

Silva

Jayasinghe

et al. 2019

Oryx

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“…Sources in Table 4 Gestation length Minimum (624 days) Mean (641 days) Maximum (667 days) Short-day breeding (total/beyond 11.75°S) 8 (21)/2 (8) 9 (21)/2 (8) 7 (21)/1 (8) Long-day breeding (total/beyond 11.75°S) 13 (21)/6 (8) 12 (21)/6 (8) 14 (21)/7 (8) Change S-L/L-S 2/1 -2/0 the same pattern for semi-captive Asian elephants in timber camps in Myanmar: the highest overall body weight was measured during monsoon months and the lowest towards the end of the dry season. By contrast, a recent study on Sri Lankan elephants found that their body condition was better in the dry season, probably because the receding water levels in reservoirs offered space for fresh grass regrowth (Ranjeewa et al 2018). As described above, freeranging Asian elephants at higher latitudes and semi-captive Asian elephants showed a moderate preference for long-day breeding, even though the long-day period more often coincided with the dry season when body condition was lower.…”

Section: Nutrition and Body Conditionmentioning

confidence: 88%

“…By contrast, a recent study on Sri Lankan elephants found that their body condition was better in the dry season, probably because the receding water levels in reservoirs offered space for fresh grass regrowth (Ranjeewa et al. ). As described above, free‐ranging Asian elephants at higher latitudes and semi‐captive Asian elephants showed a moderate preference for long‐day breeding, even though the long‐day period more often coincided with the dry season when body condition was lower.…”

Section: Factors Influencing Reproduction In Free‐ranging Semi‐captimentioning

confidence: 90%

Seasonality of reproduction in Asian elephantsElephas maximusand African elephantsLoxodonta africana: underlying photoperiodic cueing?

et al. 2018

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Animals in seasonal environments often rely on photoperiodicity to time their reproduction. Elephants have a gestation length of approximately two years and a historical geographic distribution including higher latitudes than at present, so the evolution of a seasonal breeding pattern cued by photoperiodicity and timed to the long‐day period is a theoretical option in both species. We reviewed literature on reproductive patterns in free‐ranging, semi‐captive and captive Asian and African elephants, photoperiodic cueing, seasonal variation in body condition, and other factors influencing their reproduction, as well as data from zoological collections on the timing of births. Most of the free‐ranging and all the semi‐captive and captive elephant populations showed a moderate yet distinct seasonal breeding pattern. Peak breeding activity of free‐ranging Asian elephants took place in either the dry or the wet season, with no preference for short‐day or long‐day breeding at low latitudes (close to the equator) but a preference for long‐day breeding at higher latitudes. Semi‐captive Asian elephants mainly bred in the dry season when body condition was lowest and day‐lengths were increasing. Peak conception often occurred in the wet season in free‐ranging African elephants when body condition was highest, with no evident preference for short‐day or long‐day breeding at low latitudes but preference for long‐day breeding at higher latitudes. Asian and African elephants in zoos at latitudes from 43 to 53°N tended to conceive more often during spring and summer, i.e. when day‐lengths were increasing. Body condition was not reported to vary significantly throughout the year and was rather high compared to in the wild. We hypothesise that elephants are ‘long‐day breeders’ in which the photoperiodic timing of conception can be influenced by many additional factors. Strategies to encourage natural conception in captive populations should include measures aimed at increasing breeding incentives in the northern hemisphere spring.

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“…However, in practice, the majority of vehicles to the park take selected and preferred routes, leading to an uneven distribution of vehicles within the park itself. Safaris in the UWNP are limited to approximately a third of the park (Ranjeewa et al, 2018), probably due to the higher possibility of spotting animals in this area. A typical safari tour commencing at the main gate would usually cover the central part of the park between the Udawalawe and Mau Ara reservoirs.…”

Section: Practical Issues When Using Carrying Capacity Guidelines For Setting Limits To Visitor Loadsmentioning

confidence: 99%

Towards Sustainable Tourism in Wildlife Protected Areas: Estimating Carrying Capacities for the Udawalawe National Park, Sri Lanka

Hettiarachchi

Marasinghe²,

Pilapitiya³

et al. 2021

Univ. Colombo Rev.

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Wildlife Protected Areas (PAs) are set aside with the primary objective of conserving native species and their habitats. The increasing use of such PAs for wildlife-related tourism has the potential to adversely impact the biota they seek to conserve. The main challenge for sustainable tourism is, therefore, to balance the flow of visitors while conserving the wildlife resources within the PAs. The concept of "carrying capacity" has been used to guide sustainable tourism strategies, through the generation of information on how many visitors can be accommodated within a given PA without inflicting damage. In this article, we report on the physical and real carrying capacity values calculated for the Udawalawe National Park, Sri Lanka, one of the most visited PAs in the island by both local and foreign travelers. Calculations are based on standard formulae modified to include a set of variables that are locally appropriate. The disturbance caused to the elephants, the main attraction of the Udawalawe National Park, by visitors was also factored in when calculating the carrying capacity values. Based on the generated values it is seen that the current mean vehicle and visitor loads are within acceptable ranges, although there is still a risk of over visitation, particularly during the peak periods and when guidelines are not met. Challenges of using this approach for setting visitation limits are also discussed.

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Decreasing reservoir water levels improve habitat quality for Asian elephants

Abstract: The following work is licensed under a Creative Commons: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) License.

Cited by 10 publications

References 39 publications

First country-wide survey of the Endangered Asian elephant: towards better conservation and management in Sri Lanka

First country-wide survey of the Endangered Asian elephant: towards better conservation and management in Sri Lanka

Seasonality of reproduction in Asian elephantsElephas maximusand African elephantsLoxodonta africana: underlying photoperiodic cueing?

Towards Sustainable Tourism in Wildlife Protected Areas: Estimating Carrying Capacities for the Udawalawe National Park, Sri Lanka

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