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Decreasing reservoir water levels improve habitat quality for Asian elephants

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Abstract

Population health and habitat quality are intimately related and seasonal changes in habitat quality are likely to be reflected in the body condition of animals. We studied seasonal variation of body condition in free ranging Asian elephants (Elephas maximus) in Udawalawe National Park, Sri Lanka based on visual scoring of individually identified elephants. We assessed the body condition of 218 adult females and 329 adult males from January 2008 to November 2012 and examined its relation to monthly rainfall and water level of the Udawalawe reservoir. Contrary to expectations, body condition of elephants was higher in the dry season, when primary productivity decreases due to lack of rainfall. However, the body condition showed both a seasonal and inter-annual negative co-relation with reservoir water level. A possible explanation for improved body condition in the dry season is the greater availability of fresh grass due to the emergence of reservoir bed grasslands with the drawdown of water. Our results underscore the importance of water management of large irrigation reservoirs in elephant conservation in Sri Lanka.

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... JZAR Research article al. ), living conditions (Morfeld et al. 2014Wijeyamohan et al. 2015), season (Albl 1971De Klerk 2009;Foley et al. 2001;Pinter-Wollman et al. 2009;Pokharel et al. 2017;Ramesh et al. 2011;Ranjeewa et al. 2018), husbandry parameters , reproductive status such as lactation (De Klerk 2009), faecal glucocorticoid metabolites (Pokharel et al. 2017), history of translocation (Pinter-Wollman et al. 2009) and duration of musth (Poole 1989;Somgird et al. 2016b). More extended information on previous research on elephant body condition scoring is compiled in Supplement 1 (Table S1 and S2). ...
... Both samples were balanced regarding age and sex category. We were unable to assess season for either free-ranging population, although seasonal changes in body condition do occur (De Klerk 2009;Foley et al. 2001;Ramesh et al. 2011;Ranjeewa et al. 2018). ...
... In nine out of 13 studies investigating Asian elephants in (semi-) captivity, the mean/median BCS was >0.6 of the score range, whereas data on free-ranging Asian elephants reported by Wijeyamohan et al. (2015) and Ranjeewa et al. (2018) had a mean/ median of 0.6 respectively 0.51 and our results do not even reach 0.5 (mean: 0.49 and median: 0.45). Our study thus corroborates findings from the literature with higher scores in captive compared to free-ranging populations of the Asian elephant (Table 7). ...
Article
Foot problems are a common concern in elephant husbandry. Studies on this topic with sample sizes greater than 100 animals have only been carried out in North America. We investigated foot health of 243 Asian elephants (Elephas maximus) in 69 European institutions. During on-site visits between August 2016 and July 2017, standardized pictures were taken of each elephant’s nails and pads. The pictures were analyzed with respect to pathological lesions (i.e. nail cracks, abscesses), care issues (i.e. minor abnormalities, which are easily resolvable with routine foot work), and pad structure. Of all analyzed nails and pads, 35.6% revealed varying degrees of pathological lesions, with minor nail cracks and overgrown cuticles with attachment to the nails being most frequently observed. The most lateral nail (N5) on both front feet demonstrated the highest percentage of pathological lesions, providing support to a separate study showing that the mean peak pressure of an elephant’s foot occurs along the most lateral digits; however, this was not observed along the most lateral nail (N5) of the rear feet. Three (of 243) elephants did not show any pathological lesions in their feet. The most common issues requiring foot care were fissures in the nail sole. The structure of the pads was categorized in four grades reflecting the percentage of surface marked by sulci. These four grades occurred at nearly equal frequency. Pearson product moment correlations revealed no significant association between the frequency of care issues and pathological lesions per nail. Despite this finding, it may be prudent to implement husbandry protocols that could alleviate commonly observed pathological and care foot issues in captive Asian elephants. A standardized approach to evaluate elephant foot health will provide a more objective way to monitor responses to management and medical decisions and ultimately contribute to the overall wellbeing of elephants in human care.
... Several indices have recently been developed for elephants and applied in free-ranging as well as semi-captive and captive populations (Fernando et al. 2009;Morfeld et al. 2014;Morfeld et al. 2016;Treiber et al. 2012;Wemmer et al. 2006;Wijeyamohan et al. 2015). Scores have been reported to be affected by age (Chusyd et al. 2018;Somgird et al. 2016), sex (Godagama et al. 1998;Morfeld et al. 2016;Pinter-Wollman et al. 2009;Ramesh et al. 2011), living conditions (Morfeld et al. 2014;Schiffmann et al. 2018;Wijeyamohan et al. 2015), season (Albl 1971;De Klerk 2009;Foley et al. 2001;Pinter-Wollman et al. 2009;Pokharel et al. 2017;Ramesh et al. 2011;Ranjeewa et al. 2018), husbandry parameters (Harris et al. 2008; Morfeld et al. 2016), reproductive status such as lactation (De Klerk 2009), history of translocation (Pinter-Wollman et al. 2009), stress level (Pokharel et al. 2017) and duration of musth (Poole 1989;Somgird et al. 2016). ...
... On the other hand, dietary supply and health conditions are expected to be ideal in young zoo elephants and a constant BCS may be the consequence result. In addition, reduced variance in BCS of calves and sub-adults compared to adults have been reported in freeranging Asian elephants as well (Ramesh et al. 2011;Ranjeewa et al. 2018). By implication, a significant deviation of this BCS pattern in zoo elephant calves might indicate diet or health inadequacies. ...
... According to our findings European zoo elephants express no seasonal variation in BCS. This is in contrast to reports investigating free-ranging populations of both elephant species (Albl 1971;De Klerk 2009;Pokharel et al. 2017;Ramesh et al. 2011;Ranjeewa et al. 2018). In the latter, seasonal availability and quality of diet is considered the driving factor for changing physical condition in elephants. ...
Article
In further improving zoo elephant welfare, diet and feeding regimes are key factors. Together with the encouragement of physical activity, they support the management of weight and the prevention of obesity, which is considered a common concern in zoo elephants. Besides weight monitoring, visual body condition scoring (BCS) has proven a practical tool for the assessment of (zoo) elephants' physical condition. From the individual management as well as the medical perspective, documentation of an elephant´s BCS changes over time might be much more informative than a population-wide crosssectional analysis. We present a compilation of cases where European zoo elephant BCS can be assessed against influencing factors, such as reproductive activity, physical disorders, advanced age, stressful situations and diet adaptations. The present study of the European zoo elephant population describes how various life circumstances and management adaptations are reflected in the BCS of individual elephants, and in population-wide BCS over time. An online archive to build up a reliable, individualbased data basis with minimal additional workload for elephant-keeping facilities is introduced.
... Several indices have recently been developed for elephants and applied in free-ranging as well as semi-captive and captive populations (Fernando et al. 2009;Morfeld et al. 2014;Treiber et al. 2012;Wemmer et al. 2006;Wijeyamohan et al. 2015). Scores are affected by age (Chusyd et al. 2018;Somgird et al. 2016b), sex (Godagama et al. 1998;Pinter-Wollman et al. 2009;Ramesh et Schiffmann et al. al. 2011), living conditions (Morfeld et al. 2014;Wijeyamohan et al. 2015), season (Albl 1971;De Klerk 2009;Foley et al. 2001;Pinter-Wollman et al. 2009;Pokharel et al. 2017;Ramesh et al. 2011;Ranjeewa et al. 2018), husbandry parameters (Harris et al. 2008;, reproductive status such as lactation (De Klerk 2009), faecal glucocorticoid metabolites (Pokharel et al. 2017), history of translocation (Pinter-Wollman et al. 2009) and duration of musth (Poole 1989;Somgird et al. 2016b). More extended information on previous research on elephant body condition scoring is compiled in Supplement 1 (Table S1 and S2). ...
... Both samples were balanced regarding age and sex category. We were unable to assess season for either free-ranging population, although seasonal changes in body condition do occur (De Klerk 2009;Foley et al. 2001;Ramesh et al. 2011;Ranjeewa et al. 2018 Schiffmann et al. ...
... In nine out of 13 studies investigating Asian elephants in (semi-) captivity, the mean/median BCS was >0.6 of the score range, whereas data on free-ranging Asian elephants reported by Wijeyamohan et al. (2015) and Ranjeewa et al. (2018) had a mean/ median of 0.6 respectively 0.51 and our results do not even reach 0.5 (mean: 0.49 and median: 0.45). Our study thus corroborates findings from the literature with higher scores in captive compared to free-ranging populations of the Asian elephant (Table 7). ...
Article
Full-text available
Obesity is a common problem in captive elephants. Therefore, physical state monitoring presents a critical aspect in preventive elephant healthcare. Some institutions lack the equipment to weigh elephants regularly, so body condition scoring (BCS) is a valuable alternative tool. As yet, the BCS of both elephant species has not been assessed comprehensively for the European captive population. Using a previously validated visual BCS protocol, we assessed 192 African (Loxodonta africana) and 326 Asian elephants (Elephas maximus) living in European zoos (97% of the living European elephant population). The majority of elephants scored in the upper categories with 56% of adults assessed in the range 7–10 out of 10. Adult Asian elephants had significantly lower BCS (males: mean 6.2 ± 1.0, median 6.0, range 4–8; females: mean 6.6 ± 1.3, median 6.0, range 3–9) than African elephants (males: mean 6.7 ± 0.7, median 6.0, range 6–8; females: mean 6.9 ± 1.2, median 6.0, range 1–9). Comparison with samples of free-ranging populations (163 Asian elephants and 121 African elephants) revealed significantly lower scores in free-ranging elephants independent of species, age and sex category. Compared to previous reports from captive populations, the European zoo elephant population is nevertheless less obese. In adult Asian elephant females, BCS was significantly correlated to their breeding status with lower scores in current breeders; however, breeding status was also correlated to group size, enclosure size, and a diet with less vegetables. Further attention to zoo elephant weight management is recommended with regular longitudinal monitoring by body condition scoring.
... Increasing HEC incidents has been reported in other elephant range countries (e.g. India, Srilanka) Ranjeewa et al., 2017 ;Shaffer et al., , 2014 . ...
... Thus, the incidents seem comparatively more minor(Figure 3). Increasing HEC incidents have been reported in other elephant range countries (e.g., India, Srilanka)Ranjeewa et al., 2017;Shaffer et al., , 2014 . ...
... Habitat management through managing ecological corridors and enriching protected areas expects to reduce human-elephant interactions by reducing the need for elephants to venture into human-dominated habitats. Elephants are forest animals, but edge species, preferring habitats with intermediate disturbance rather than undisturbed forests [143][144][145][146]. Elephants are often attracted to landscapes disturbed by humans, thereby increasing the chances of HEC [31]. ...
Article
Full-text available
Animal-borne aversive geofencing devices (AGDs, or satellite-linked shock collars) are commercially available and used on livestock to restrict their movement within a virtual boundary. This technology has potential application as a human-wildlife conflict mitigation tool, where problem animals might be conditioned to avoid human-dominated habitats by associating an audio warning with a subsequent electric shock, which is delivered if the audio warning is ignored. Ensuring that high standards of animal welfare are maintained when implementing such tools is important for acquiring manager and community acceptance of such approaches. We conducted two pilot experiments with eight captive Asian elephants using mild electric shocks from a modified dogtraining collar fitted around the neck, as part of an ongoing effort to develop AGDs suitable for mitigating human-elephant conflict. As part of these experiments, we assessed elephants' behavioural and physiological stress before, during and after our experiments. During the experiments elephants wore collars up to nine consecutive days and received a small number of electric shocks on 1–3 consecutive days. Bootstrapped principal component analysis showed that daily activity budgets of individual elephants on experiment days were not different to the pre-experiment days. Generalised linear mixed-effect model (GLMM) showed that anxiety/stress behaviours increased on the first day of acclimatising to the collar and on testing days (i.e. days they received shocks) of the first experiment, but not during the second experiment relative to pre-experiment days. Analysis of faecal cortisol metabolite (FCM) concentrations using GLMM showed that FCM concentrations were higher in samples collected ~24 hrs and ~48 hrs after testing days compared to baseline levels as expected given the lag time for excretion of cortisol metabolites. These elevated anxiety/stress behaviours and FCM concentrations returned to baseline levels shortly after the experiment. Therefore, we conclude that AGDs did not produce lasting behavioural or physiological stress effects in elephants during this short term study but recommend further studies with a larger sample of elephants to confirm the transferability of these findings.
... Habitat management through managing ecological corridors and enriching protected areas expects to reduce human-elephant interactions by reducing the need for elephants to venture into human-dominated habitats. Elephants are forest animals, but edge species, preferring habitats with intermediate disturbance rather than undisturbed forests [143][144][145][146]. Elephants are often attracted to landscapes disturbed by humans, thereby increasing the chances of HEC [31]. ...
Article
Full-text available
Asian elephants are a principal cause of human-wildlife conflict. This results in the death/injury of elephants and humans and large-scale crop and property damage. Most current human-elephant conflict (HEC) mitigation tools lack the flexibility to accommodate the ecological needs of elephants and are ineffective at reducing HEC in the long-term. Here we review common HEC mitigation tools used in Asia and the potential of Aversive Geofencing Devices (AGDs) to manage problem elephants. AGDs can be configured to monitor animal movements in real-time and deliver auditory warnings followed by electric stimuli whenever animals attempt to move across user-specified virtual boundaries. Thus, AGDs are expected to condition elephants to avoid receiving shocks and keep them away from virtually fenced areas, while providing alternative routes that can be modified if required. Studies conducted using AGDs with other species provide an overview of their potential in conditioning wild animals. We recommend that the efficacy and welfare impact of AGDs be evaluated using captive elephants along with public perception of using AGDs on elephants as a means of addressing the inherent deficiencies of common HEC mitigation tools. If elephants could be successfully conditioned to avoid virtual fences, then AGDs could resolve many HEC incidents throughout Asia.
... Asian elephants have been listed as 'Endangered' under IUCN red listing criteria (Choudhury et al., 2008). Out of these three sub species, the one found in Sri Lanka is native to the island (Ranjeewa et al., 2018: Fernando, 2015. ...
Article
Full-text available
Interaction with elephants is reflected everywhere across the socio-cultural, political and ecological canvas of Sri Lankans. Prior to the British colonization of Sri Lanka, the elephant population was higher and its distribution across the island was wider. The elephant population was greatly reduced and its habitats were limited to the dry zone ecosystems as a result of colonial plantation and industrial activities. However, even today there remain a few elephant herds in the rain forests despite the fact that they are faced with a number of survival challenges. Sinharaja is one such rain forest that remains as a biodiversity rich and culturally unique world heritage site in Sri Lanka. There are more than 24 villages in the periphery and the villagers have been keeping their traditional folk life for thousands of years. Against this background, this paper focuses on the last few elephants of Sinharaja rain forest, with attention to their role in the ecosystem and their impct on the socio-cultural environment. Further, the paper discusses how environmental conservation needs clash with cultural, socioeconomic and political values, regarding the welfare of the elephant populaton. As the research employed a qualitative methodology, the primary and secondary data were gathered from focused group interviews, semi-structured interviews, direct observations, and published secondary sources, and the data analysis was carried out by means of a thematic analysis. On the whole, the study reveals the importance of elephants as an integral component of the ecosystem and proposes application of in-situ conservation methods to ensure their existence in Sinharaja. Finally, it recommends introducing new herds of female elephants to increase the elephant population of Sinharaja.
... The boundaries of wildlife administrative regions deployed and published by DWC Sri Lanka (2012) has been overlaid to understand the regional distribution of each HEC type. (Ekanayaka et al., 2011;Fernando, Leimgruber et al. 2011;Ranjeewa et al., 2018). The unprecedented number of HEC hotspots in 2016 may have been the result of the long-term effect of drought together with LULCC impacts. ...
Article
Human–elephant conflict (HEC) is a key environmental issue in number of Asian countries, including Sri Lanka. Incidents of HEC have significantly increased in Sri Lanka between 1991 and 2018, with 1734 human deaths reported in this period (281% increase), 4837 elephant deaths (1172% increase), 1053 human injuries (140% increase) and more than 23,000 property damage reports (1406% increase). In this study we present a Sri Lanka wide analysis to explore the role of land use and land cover change (LULCC) in relation to HEC, using official government data and a land cover change dataset (1993–2018) recently developed by the authors using satellite imagery from the Landsat archive. We investigated rates of HEC over time and compared these to rates of LULCC over the same period. We also present spatial analytics of HEC and LULCC, as well as determining hotspots of HEC and LULCC using a kernel density estimator. Annual HEC incidents were found to broadly increase in line with land use change events (r = 0.43, p < 0.05). Human deaths, elephant deaths, human injuries and property damage hotspots show distinct spatial patterns: human deaths and injuries being more concentrated in the North West, Polonnaruwa and Ampara, wildlife regions; while elephant deaths are spread throughout the HEC region and property damage is high in the Central, Polonnaruwa Anuradhapura, North West, and Southern wildlife regions. We found a strong negative correlation between HEC location and distance to LULCC events. In total, 98% HEC occurred within 1 km of an area that experienced recent LULCC Since 2017, the primary HEC hotspots have shifted to the south and east of the country in concert with LULCC. These countrywide perspectives could help inform HEC mitigation strategies in Sri Lanka and other countries facing similar human-wildlife challenges.
... Increasing HEC incidents has been reported in other elephant range countries (e.g. India, Srilanka) ( Karanth et al., 2013 ;Ranjeewa et al., 2017 ;Shaffer et al., 2019Shaffer et al., , 2014 . ...
Article
Full-text available
Human elephant conflict (HEC) is rapidly increasing throughout the Asian elephant range countries including Nepal. HEC occurs in the form of human deaths and injuries, and crop as well as property losses. We compiled 10,798 incidents of HEC including attacks on humans, crop and property losses caused by elephants in the Chure Terai Madhesh Landscape, Nepal, between January 2001 and June 2020. We interviewed 10.3% of the total households affected by HEC using structured questionnaire. We used multivariate analysis to identify landscape predictors associated with HEC. The intensity of HEC was high in the areas with higher forest fragmentation, vicinity to forests, protected areas, and larger coverage of seasonal surface water. Landscape heterogeneity, effective mesh size and altitude also contributed in HEC. Socio-economically marginalized communities living close to forests are more vulnerable to HEC. The spatial risk map of HEC identified Jhapa and Koshi in the eastern region; Parsa and Chitwan in the central region, Bardiya and Kanchanpur in the western region as HEC hotspots. Restoration of forests and corridor functionality in these hotspots could reduce HEC. The comprehensive understanding of HEC from this study provides important insights to devise strategies and actions for mitigating the HEC at the landscape level.
... Increasing HEC incidents has been reported in other elephant range countries (e.g. India, Srilanka) ( Karanth et al., 2013 ;Ranjeewa et al., 2017 ;Shaffer et al., 2019Shaffer et al., , 2014 . ...
Article
Full-text available
Human elephant conflict (HEC) is rapidly increasing throughout the Asian elephant range countries including Nepal. HEC occurs in the form of human deaths and injuries, and crop as well as property losses. We compiled 10,798 incidents of HEC including attacks on humans, crop and property losses caused by elephants in the Chure Terai Madhesh Landscape, Nepal, between January 2001 and June 2020. We interviewed 10.3% of the total households affected by HEC using structured questionnaire. We used multivariate analysis to identify landscape predictors associated with HEC. The intensity of HEC was high in the areas with higher forest fragmentation, vicinity to forests, protected areas, and larger coverage of seasonal surface water. Landscape heterogeneity, effective mesh size and altitude also contributed in HEC. Socioeconomically marginalized communities living close to forests are more vulnerable to HEC. The spatial risk map of HEC identified Jhapa and Koshi in the eastern region; Parsa and Chitwan in the central region, Bardiya and Kanchanpur in the western region as HEC hotspots. Restoration of forests and corridor functionality in these hotspots could reduce HEC. The comprehensive understanding of HEC from this study provides important insights to devise strategies and actions for mitigating the HEC at the landscape level.
... Increasing HEC incidents has been reported in other elephant range countries (e.g. India, Srilanka) (Karanth et al., 2013;Ranjeewa et al., 2017;Shaffer et al., 2019Shaffer et al., , 2014 . ...
Article
Full-text available
Human elephant conflict (HEC) is rapidly increasing throughout the Asian elephant range countries including Nepal. HEC occurs in the form of human deaths and injuries, and crop as well as property losses. We compiled 10,798 incidents of HEC including attacks on humans, crop and property losses caused by elephants in the Chure Terai Madhesh Landscape, Nepal, between January 2001 and December 2020. We interviewed 10.3% of the households affected by HEC using structured questionnaire. We used multivariate analysis to identify landscape predictors associated with HEC. The intensity of HEC was high in the areas with higher forest fragmentation, vicinity to forests, protected areas, and near seasonal surface water areas. Landscape heterogeneity, effective mesh size and altitude also contributed in HEC. Socio-economically marginalized communities living close to forests are more vulnerable to HEC. The spatial risk map of HEC identified Jhapa and Koshi in the eastern region; Parsa and Chitwan in the central region, Bardiya and Kanchanpur in the western region as HEC hotspots. Restoration of forests and corridor functionality in these hotspots could reduce HEC. The comprehensive understanding of HEC from this study provides important insights to devise strategies and actions for mitigating the HEC at the landscape level.
... 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. ...
... Group n a (95% CI) asymptotic body mass (Brown, 2014) yet often live in natural habitats with seasonal fluctuations of resource availability (Codron et al., 2012) that also lead to seasonal fluctuation in body condition (e.g. Foley et al., 2001;Pokharel et al., 2017;Ranjeewa et al., 2018), it is unlikely that a systematic cyclicity of body mass with age can be observed in free-ranging populations, because resources of differing quality are consumed by animals of all ages. The combination of variable chewing efficiency and resource availability in free-ranging elephants may render these species particularly prone to reported inter-individual fitness differences (Lee et al., 2013). ...
Article
Elephants do not replace deciduous teeth once with permanent teeth as most mammals, but replace a single cheek tooth per jaw-side five times in their lives in a process called molar progression. While this gradual process has been well-documented for the purpose of age determination, a less-considered possible side effect of this progression is that functional chewing surface fluctuates, being larger when two cheek teeth are both partially in use and smaller when only one cheek tooth is used fully. We found that body mass of both breeding and non-breeding female zoo elephants (Elephas maximus, Loxodonta africana) shows a cyclic undulation with peaks separated by many years, which is therefore unrelated to reproduction or annual seasonality. We propose variation in functional chewing surface, resulting chewing efficiency, and resulting increased food intake and/or digestive efficiency as the underlying cause. As elephants reproduce all year-round and thus are not synchronized in their molar progression pattern, climate-related fluctuations in resource availability are likely to mask this pattern in free-ranging animals. In contrast, it emerges under the comparatively constant zoo conditions, and illustrates the relevance of the dental apparatus for herbivorous mammals. The combination of variable chewing efficiency and resource availability in free-ranging elephants may render these species particularly prone to reported inter-individual fitness differences.
... 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. ...
Article
• 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.
... Creating additional, year-round artificial water sources in areas appropriate for the ecosystem should also help improve elephant habitat, and increase elephant presence and abundance in protected areas. Moreover, as water levels in these reservoirs recede, short graminoid species quickly spread across the flood plain, providing abundant forage for the elephants (Ranjeewa et al., 2018). ...
Article
Protected areas provide some of the last refuges for Asian elephants in the wild. Managing these areas for elephants will be critical for elephant conservation. Scientists know little about elephant habitat use in Asia and how invasive species or livestock grazing influence habitat use. We studied these issues in two protected areas in Sri Lanka, Udawalawe National Park and Hurulu Eco-Park. These areas contain some of Sri Lanka's largest remaining grasslands. These grasslands are threatened by the invasive and toxic shrub, Lantana camara, and are used for illegal livestock grazing. To measure habitat use by elephants and livestock, we conducted dung surveys along over 50 km of transects stratified across grassland, scrub, and forest. We surveyed 159 vegetation plots along these transects to assess plant composition, and mapped habitat types based on satellite images. We used mixed-effect models to determine the relative importance of habitats, livestock presence, and plant associations for elephant use. Elephant presence was greatest in scrub and grassland habitats, positively associated with both livestock presence and short graminoids, and unaffected by L. camara, which was widespread but at low densities. Given the importance of these areas to elephants, we recommend a precautionary management approach that focuses on curbing both illegal grazing and the spread of L. camara.
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Electric fences are widely used in human–elephant conflict mitigation. However, elephants constantly challenge and overcome fences, which is a growing concern. We studied how elephants crossed the perimeter electric fence around the Udawalawe National Park (UWNP), Sri Lanka. Using camera traps, we monitored 18 fence posts and an open gate in the fence over 605 days from 2016 to 2019. Photographs of 3097 fence crossings were analysed to obtain demographic data for fence crossing elephants, crossing methods, and the daily and seasonal timing of fence crossing. We identified 77 adult males and 12 adult females that crossed the fence, which represent about 17% of the adult elephants in UWNP. Most of the crossings were through the open gate at night. Elephants used a variety of crossing methods, comprised of crossing at the open gate, at previously toppled posts, by crashing through wires and stepping over wires, as well as by using the trunk or forefeet to topple posts. Fence voltage was not a determinant of fence crossing. The frequency and timing of fence crossings varied between locations with later exits and less time spent outside, at crossing points bordering human dominated areas. Our results emphasis on the importance of taking into account the problem solving abilities of elephants in fence design and location, such as energising fence posts and constructing exclosure fences at the boundaries of crop fields and settlements, in employing electric fences to mitigate human‐elephant conflict.
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Asian Elephants feed predominantly on grass. The comparative nutritional contribution of grasses and other elephant forage is not known. Therefore, the proximate nutrition of food plants selected by elephants, and the relationship of their diet composition to body condition and gender were examined in this study. Proximate analysis was conducted on 11 plant species recognised upon 66h of opportunistic focal animal sampling. Five species among them were grasses, including the invasive Megathyrsus maximus. The micro-histological composition of freshly collected dung from 26 identified elephants was assessed against their body condition and gender. Associations, comparisons, and hypotheses were tested. Dicots were significantly high in dry matter and low in moisture, while monocots were high in moisture and low in dry matter (p <0.001). The average monocot: dicot ratio was 1: 0.73 in elephant diet. However, it was observed that the monocot composition in the male diet was significantly higher than dicots (p <0.001), while there was no significant difference in the female diet composition. Elephant body condition did not show any correlation with the abundance of monocot or dicot plant tissues. The preliminary study implies that dry matter nutrients in dicots and moisture in monocots influence diet selection of elephants. Their diet composition was associated with gender but did not correlate with body condition. M. maximus was not outstanding in nutrition from the selected plant species.
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In protected areas (PAs) designated for the conservation of biodiversity, temporal landscape changes do occur, driven by natural and anthropogenic factors. Such changes may impact on the conservation value of the PA. In a wildlife PA, changes in habitat extents could adversely affect some of the faunal species. Our objective was to assess temporal changes in the cover of three major habitat types in the Udawalawe National Park (UWNP) that have occurred over a short term. Based on the outcome, we aimed to determine the potential impacts such changes would have on the wildlife. Considering that UWNP was established primarily for conserving the nationally threatened and flagship species Elephas maximus, we carried out field studies and decided on three relevant habitat types - forest, scrub, and grassland. We used multi-temporal satellite images with ground truthing for assessing habitat extents in the years 2005, 2010, 2015, and 2019. Habitat cover maps were prepared using supervised classification and changes in the extents of the selected habitats were assessed. Between 2005 and 2019, the areas under forest and scrub had increased. The grassland has considerably decreased, mainly owing to invasion by scrub. Grassland depletion adversely impacts the elephant whose preferred food is grass and the high population of elephants in UWNP aggravates the situation. Depletion of food resources within the park would also lead to an increase in the human-elephant conflicts in border villages. Thus, in this study we highlight the importance of monitoring temporal changes in habitat cover in order to manage the PA and the inhabiting wild elephants. Keywords: Elephas maximus; habitat cover mapping; protected areas; remote sensing.
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This study aimed at relating body condition score (BCS) to ultrasound measurements of subcutaneous fat over the areas most commonly used to BCS Holstein-Friesian cows, and determining the practicality of ultrasound measurement of subcutaneous fat for assessment of energy status of the cow. Twenty-eight cows were scored to the nearest quarter point on a scale of 1-5 (1=thin and 5=fat) using both visual and tactile techniques. On the same day, ultrasound measurements of subcutaneous fat were obtained at the lumbar transverse process, thurl and near the tailhead areas on both sides of the cow making six locations. Spearman's rank correlation coefficients between the six ultrasound locations ranged from 0.72-0.93 and were all significantly different from zero (p<0.01). Correlation coefficients between BCS and the mean lumbar, thurl and tailhead ultrasound measurements ranged between 0.67-0.72 and were also significantly different from zero (p<0.01). BCS was highly and significantly correlated to ultrasound measurements of subcutaneous fat. Ultrasound can be used independently or in conjunction with BCS to estimate the nutrition and energy status of cows.
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Human-elephant conflict (HEC) is widespread across Asian elephant range (Sukumar 1989; Santhiapillai & Jackson 1990). The threat to elephants from HEC makes it a serious conservation problem. Loss of human life and limb, and economic losses due to crop raiding and property damage by elephants, makes it a major socio-economic and political issue (Fernando 2006). Rapidly expanding human populations result in ever greater conversion of elephant habitats and increased interaction between humans and elephants, leading to escalation of HEC. ‘Development’ and wide media coverage of the effects of HEC on people change perceptions and expectations, causing decreased tolerance of damage caused by elephants.
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The Loxodonta africana calf depends on its mother for 3-5 yr. During this period it develops complex social relationships with members of its family unit. In Amboseli National Park, Kenya, mothers interact with and allocate care differently to male and female calves. Males suckled more frequently but moved away from their mothers earlier; females remained close to their mothers and engaged in more friendly and aggressive interactions. Male calves leave the family in order to interact, and especially to play, with nonfamily members; females interacted more within the family. Differences in interactions and relationships are related to later mating tactics and association patterns of adults.-from Authors
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Body size is an important influence on the life history of males of polygynous mammals because it is usually highly correlated with fitness and is under intense selection. In this paper, we investigated the effect of high-risk foraging behavior (crop raiding) and genetic heterozygosity on male body size in a well-studied population of African elephants. Crop raiding, the foraging on cultivated food crops by wildlife is one of the main causes of wildlife human conflict and is a major conservation issue for many polygynous mammals that live in proximity to agriculture or human habitation. Body size was estimated using hind foot size, a measure strongly correlated with stature and mass. Crop raiding predicted male size in adulthood, with raiders being larger than nonraiders. However, elephants that became raiders were neither larger nor smaller for age when young. Enhanced growth rates and size among raiders suggest that taking risks pays off for males. Lastly, genetic heterozygosity had no effect on size for age in male elephants, most likely because low-heterozygosity males were rare. Risky foraging behavior can evolve as a result of strong sexual selection for large size and condition-dependent mating success in males. We discuss the implications of these results for managing human--wildlife conflict. Copyright 2011, Oxford University Press.
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Precipitation quantity has been shown to influence grassland aboveground net primary productivity (ANPP) positively whereas experimental increases in of temporal variability in water availability commonly exhibit a negative relationship with ANPP. We evaluated long term ANPP datasets from the Konza Prairie Long Term Ecological Research (LTER) program (1984–1999) to determine if similar relationships could be identified based on patterns of natural variability (magnitude and timing) in precipitation. ANPP data were analyzed from annually burned sites in native mesic grassland and productivity was partitioned into graminoid (principally C4 grasses) and forb (C3 herbaceous) components. Although growing season precipitation amount was the best single predictor of total and grass ANPP (r 2=0.62), several measures of precipitation variability were also significantly and positively correlated with productivity, independent of precipitation amount. These included soil moisture variability, expressed as CV, for June (r 2=0.45) and the mean change in soil moisture between weekly sampling periods in June and August (%wv) (r 2=0.27 and 0.32). In contrast, no significant relationships were found between forb productivity and any of the precipitation variables (p>0.05). A multiple regression model combining precipitation amount and both measures of soil moisture variability substantially increased the fit with productivity (r 2=0.82). These results were not entirely consistent with those of short-term manipulative experiments in the same grassland, however, because soil moisture variability was often positively, not negatively related to ANPP. Differences in results between long and short term experiments may be due to low variability in the historic precipitation record compared to that imposed experimentally as experimental levels of variability exceeded the natural variability of this dataset by a factor of two. Thus, forecasts of ecosystem responses to climate change (i.e. increased climatic variability), based on data constrained by natural and recent historical rainfall patterns may be inadequate for assessing climate change scenarios if precipitation variability in the future is expected to exceed current levels.
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Data on elephant movements collected during the project on the ecology of Asian elephant Elephas maximus in the Mudumalai Sanctuary are being used to develop management recommendations for the study population. -from Author
Chapter
AnatomyDigestive PhysiologyDisorders of the Digestive System
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Asian elephants are ‘endangered’ but come into significant conflict with humans. Sri Lanka holds an important position in relation to Asian elephants, both in terms of species conservation and human-elephant conflict mitigation. Historical aspects of the two main conservation agencies and lack of coordination between them has prevented a landscape level holistic approach to conservation in general and elephants in particular. The primary objective of elephant management is human-elephant conflict mitigation and secondarily elephant conservation. Many human-elephant conflict mitigation activities are ineffective and in some cases cause its escalation and wider spread. Others are extremely detrimental to elephant conservation. Effective human-elephant conflict mitigation and elephant conservation requires a paradigm change. Elephant management needs to be based on science and evidence rather than outdated beliefs and false assumptions. Unless immediate and effective remedial measures are taken, human-elephant conflict will continue to escalate and the elephant population continue to decline. Ceylon Journal of Science (Bio. Sci.) 44 (1) : 1-11, 2015
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Body growth, expressed as shoulder height and body weight, is compared between 3 captive populations of Elephas maximus Linnaeus, 1758 from Southeast Asia (Thailand and Myanmar), Sri Lanka and 4 European zoos. Under optimal nutritional conditions Asian elephant bulls invest in shoulder height, females in storing resources, ie higher relative body weights. A comparison of 5 Sri Lankan phenotypes, defined by the occurence and the growth type of upper incisivi, revealed that the frequencies of certain physical characteristics such as spinal configuration, extent of depigmentation of trunk, temples, ears and shoulders, as well as eye colours are linked to certain types of incisivi. In males 2 different growth types were found: the relatively fast growing tusker or 'etha' reaching maximum body height and weight at a younger age than the tuskless 'aliyas' and 'pussas'. Both types differ significantly as to the extent of optical marks in terms of depigmentated skin patches at the head pole, which seem to represent the role of conspicious hair colours and tufts of polygamous ruminant ungulates in optical communication.
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The Asian elephant has had a unique cultural association with people. Unfortunately, elephants and people have also been in conflict, resulting in the decline in elephants throughout their former range in Southern Asia. This book provides an ecological analysis of elephant human interaction and its implications for the conservation of elephants. The foraging habits of elephants and their impact on vegetation are considered, along with the interactions that occur between elephants and humans. The ecological data provide the basis for recommendations on elephant conservation and management, keeping in view the socioeconomic imperatives of the Asian region.This first comprehensive account of Asian elephant ecology will be of particular interest to conservation biologists and mammalogists.
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Fifty-six cull Holstein dairy cows with various body condition scores were followed to slaughter. prior to slaughter, cows were weighed on a digital scale, hook to hook and hook to pin dimensions were measured, and age was estimated by dentition. Twenty-four hours after slaughter, 9th to 11th rib sections were collected and weighed, and bone-free tissue was dissected and weighed. Deboned tissue was freeze-dried, ground, and analyzed for DM, ether extract, CP, and ash. One unit increase of body condition change was associated with a change of 56 kg live weight and 12.65% ether extract and –12.20% CP. Tissue DM increased by 7.23% per unit of body condition increase, largely due to increase in the percentage of ether extract. Regression of composition on body condition score revealed r2 of .69 for DM, .61 for CP, and .57 for ether extract. Body condition score is highly correlated with composition of the 9th to 11th rib tissue.
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Primary productivity and herbivory were studied in the Serengeti National Park, Tan- zania, and Masai Mara Game Reserve, Kenya, during the annual cycle of 1974-1975, and wet-dry season transitions in 1976-1979. Basic state variables measured were aboveground plant biomass inside permanent and temporary fences, and outside fences. Productivity was calculated as the sum of positive plant biomass increments. Control productivity (cPn) was calculated from biomass dy- namics inside permanent fences. Temporary fences were moved in concert with grazing by the region's abundant ungulates to estimate actual aboveground primary productivity (aPn).Primary productivity was highly stochastic with productive periods poorly synchronized even among nearby sites. Short- term productivities could be extremely high, exceeding 30 g.m-2 .dl. Grazing animals adjusted their densities in relation to grassland productivity. The average proportion of annual aPn that was consumed by herbivores was 0.66, with a minimum of 0.15 and a maximum of 0.94. Green forage was available everywhere late In the wet season in May but was available only at high rainfall sites in the northwest late in the dry season in November. By the end of the dry season, the residual plant biomass outside fences averaged only 8% of cPn. Nomadic grazers moved seasonally in response to grassland pro- ductivity. The growing season ranged from 76 d in low rainfall areas to virtually continuous in high rainfall areas. Annual cPn was linearly related to rainfall and averaged 357 g.m-2.yr-1 over the year and 1.89 g.m-2,d-1 during the growing season. Actual aPn was substantially greater than cPn at most sites, averaging 664 g.m-2.yr-1. Growing season aPn averaged 3.78 g.m-2.d-1. Grazing stimulated net primary productivity at most locations, with the maximum stimulation at intermediate grazing in- tensities. Stimulation was dependent upon soil moisture status at the time of grazing. Rain had a diminishing effect on primary productivity as the wet season progressed and plant biomass accu- mulated. Part of the stimulation of grassland productivity by grazing was due to maintenance of the vegetation in an immature, rapidly growing state similar to that at the beginning of the rainy season. Slnce grazers overrode rainfall-determined productivity patterns, aPn was more closely related to grazing intensity than to ranfall. Grazing was heavier on grasslands that were intrinsically more productive. Rate of energy flow per unit of plant biomass was much higher in grazed vegetation. Grazers ate green leaves almost exclusively during the wet season, but species composition of the diets of different grazers differed markedly. Diets of nomadic grazers were very different in the wet and dry seasons. Vegetation dried out rapidly at the onset of the dry season and dry plant tissues made up a substantial proportion of ungulate dry season diets. However, green forage commonly was more abundant in diets than in the vegetation. Grazing increased both forage quality and its rate of pro- duction. Zebras supplemented a high-bulk diet by eating the seeds of awnless grasses. The foraging patterns of different grazers were differentiated by several vegetation properties, including productivity, structure, and species composition, in a manner suggesting resource partitioning. The relationship between the stability of vegetation functional properties and community species diversity was posltive in five of seven tests. Greater species diversity was associated with greater biomass stability through the seasons, greater resistance to grazing by a single species of ungulate in both the wet and dry seasons, and greater resilience after grazing. Species diversity was not associated with greater resistance to grazing by several ungulate species or to plant species extinction. Specific properties of trophic web members were identified that produced greater functional stability in more diverse communities. Fire does not appear to have important effects upon the functional properties of the grasslands except for a weak stimulation of productivity in the wet season immediately following dry season burning. Fire did have an important effect upon structural properties of the vegetation that would tend to regulate ungulate feeding. The ecology of neither the plants nor the animals in the Serengeti ecosystem can be understood in isolation; many traits of both suggest coevolution among trophic web members. The functional dynamics of the trophic web suggest that the acceleration of energy and nutrient flow rates due to intense herbivory has resulted in the development of an entire consumer food web due to additive fluxes rather than mere quasi-parasitic fluxes from plants to animals.
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Linear dominance hierarchies are thought to form within groups of social animals to minimize conflict over access to resources. Dominance in both male and female African elephants (Loxodonta africana) is based mostly on intrinsic factors relating to age, and dominance hierarchies have been described within and between family groups of females. Very little is reported about male elephant social structure and dominance has only been described at the level of one-on-one contests. We test the hypothesis that male African elephants form linear hierarchies when resources are limited by monitoring a known group of elephants in Etosha National Park, Namibia, and measuring dominance interactions between males (outside the context of reproduction) during the dry season of 4 consecutive years. We show that males form a stable linear dominance hierarchy under normal arid conditions (in 2005 and 2007) when water is limited and resource competition is high. In unusually wet years with increased water availability (in 2006 and 2008), there is no linearity to the dominance hierarchy, less interaction between individuals and more agonistic behaviors exhibited, particularly in lower ranking individuals. This is the first study to quantify the existence of a linear dominance hierarchy in male African elephants as well as the effect of climatic fluctuations on dominance from year to year.
Article
Per-capita feeding time was nearly exactly inversely proportional to group size in small-crowned trees with little fruit, but was essentially independent of group size in large-crowned trees with abundant fruit. The cost of indirect food competition in large groups was not compensated by increased rates of ingestion, preferential use of large trees, of a higher rate of fruit tree encounter per distance travelled. Instead, foraging effort (distance travelled, number of minutes devoted to foraging, total activity minutes per day) increased at large group sizes. Estimates of total energy intake and expenditure suggest that net energy gain is constant for individuals in group sizes of 5-12. The upper limit to group size is probably set by the daylength available for foraging in large groups. Aggression in food trees increased in frequency in larger groups, but the relative feeding rates of dominants and subordinates of a given rank did not appear to depend on group size. Observed decreases in per-capita food intake due to either indirect or aggressive food competition within large groups are substantially greater than the 4% gain in mean food intake that large groups achieve by displacing smaller groups from fruit trees. -from Author
Article
A description of sexual behavior was formulated based upon observations of both captive and wild Asiatic elephants. Communication mechanisms, including visual, acoustic, tactile, and chemical signals, are reviewed. The importance of chemical signals in the integration of elephant sexual behavior is emphasized. Secretions from the temporal glands of the male may possibly function as identifiers and indicators of age and sex. Vaginal secretions from the female appear to be involved in indicating her state of receptivity to the male. It is suggested that the seasonal aggressiveness shown by male elephants, termed musth, is comparable to rutting behavior in other ungulates, such as deer. Estrus in the female was determined by behavioral criteria and through vaginal smears. The interval between estrous periods in females is approximately 3 weeks, with a mean of 22 days and a range of 18 to 26. The mean duration of estrous periods for 6 females was 4 days. Sexual behavior patterns were broken down into three categories: Contact promoting behaviors include the exchange of chemical information employing the trunks. Various areas of the body have different valences depending on the reproductive condition of the interacting animals. Females tend to investigate the male's temporal gland most frequently and males investigate the urogenital sinus of the female. Precopulatory behavior involves wrestling with intertwined trunks, reaching over by the male, driving, neck biting, and attempted mounts. Copulation requires the complete cooperation of the female who remains passive and standing or kneeling. The male mounts and through independent movements of the penis achieves intromission. Intromission is brief, being less than 8 seconds in duration and the total duration of a mount is often less than 30 seconds. The number of mounts per ejaculation by the male varies between 4 and 2. The number of intromissions per ejaculation varies from 1.4 to 3.5. Typically the females are organized into cohesive matriarchal herds which travel about in a rather large home range which overlaps the home ranges of individual males. Adult males are typically solitary in their movements unless they join a cow herd. If a cow is in estrus, a male will remain with the cow herd actively courting her. Competition. between males can arise when more than one male comes into contact with the same cow herd. The sexual behavior of African elephants is contrasted with the behavior patterns described for the Asiatic elephant. The two elephant species show broad similarities in behavior and temporal patterning. The function of the temporal gland in the Asiatic elephant male appears to be quite different from the functions implied from the African elephant studies. The courtship and copulation behaviors shown by the elephant are interpreted with respect to its evolutionary history. It is concluded that the major modifications in elephant behavior involve no departures from homologous behavior patterns in other mammals but rather involve adaptations to major structural differences that the elephant has evolved including its graviportal support system and its prehensile trunk. No major departures in social structure and behavior can be discerned for the elephant when it is compared with other ungulate species.
Article
A scoring system with 1 to 5 scale was devised to measure body condition of dairy cows at any point during the lactation cycle. Cows were scored on appearance and palpation of back and hind quarters only. Relationships of body weight, frame size measurements, milk production, and characteristics related to the body condition scoring system were determined. During 18 too, 28 cows in each of 29 dairy herds were used for body measurements and body condition scores. Data were obtained from each herd at 3-mo intervals. Body weight and frame size measurements could not be correlated with body condition score. Dairy cows of greatest efficiency of milk production showed no significant increase in body condition during lactation, had fewer days open, but had lower per- sistency of lactation. Dairy cows that in- creased significantly in body condition during lactation were less efficient pro- ducers, had a greater number of days open, and had high body condition scores at the end of lactation. The body condition scoring system is a means of accurately determining body condition of dairy cows, independent of body weight and frame size.
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This paper reports on important behavioural aspects of the Asiatic elephant (Elephas maximus) in South-East Sri Lanka (Ceylon), in relation to recommendations for its conservation. The activity cycle of the elephant has been investigated in relation to local or short-range movements which were found to be diurnally rhythmic. The elephant was estimated to spend about 17 to 19 h/day feeding. The feeding cycle is seen to consist of three successive phases, namely (1) rapid movement and low feeding rate, (2) little movement and high feeding rate, and (3) a certain amount of movement and relaxed feeding. During a given feeding cycle an elephant consumes about 150 kg of fresh vegetation and defecates about 80 kg of it per day. The dynamics of grass feeding were worked out for a herd of elephants in the Gal Oya National Park. The outlook for the elephant population in South-East Sri Lanka has been critically analysed with reference to its mode of habitat utilisation. The main constraints introduced into its ecosystem are discussed, namely blocking of migratory routes, burning of grassland, construction of roads, grazing of domestic cattle in its home ranges, felling of trees by villagers, and an over-population of water buffalo (Bubalus bubalis). Measures for conservation are briefly dealt with.
Article
Male Loxodonta africana spent more time in association with females during musth than during non-musth periods. Males were more aggressive during their musth periods. Occurrence and duration of musth were age-related: no male under 24 yr was seen in musth; bouts of musth among younger individuals were short and sporadic, while older males experienced longer more predictable periods of musth on an annual basis. Males in musth were observed year-round, but frequency of musth males was highest during and following the 2 rainy seasons and, in general, good rainfall years had higher frequencies of males in musth than did poor rainfall years. Number of males in musth per month correlated closely with the number of females observed in estrus, but since estrus lasts only 4-6 days, while musth may last several months, onset of musth was not necessarily triggered by onset of estrus in a particular female. The musth periods of different males were asynchronous and each male came into musth at a specific time of year. This period was relatively consistent from one year to the next, particularly among older males. Males in musth advertised their heightened sexual and aggressive state through visual and olfactory signals and by vocalizing. These signals announce identity, condition and location to both rival males and to potentially receptive females. The physical and behavioral characteristics and temporal patterning of musth are very similar in African and Asian elephants. -from Author
Article
We provide estimates of population size and other demographic variables for individually-identified Asian elephants (Elephas maximus) in Uda Walawe National Park (UWNP), Sri Lanka based on systematic year-round observations. Two hundred and eighty-six adult females and 241 adult males were identified, of which four adults (2% of males) had tusks. Sightings-based demographic models showed seasonal immigration and emigration from the study area. The total population, including non-adults, was between 804 and 1160 individuals. Density ranged from 102 to 116 adult females per 100 km(2) and remains at this level throughout the year. This large, un-fragmented population of Asian elephants should be of high conservation priority. We find that estimates of survivorship and migration rates should be based on long sampling intervals when possible, but estimates of density and population size can still be made when observations are constrained to shorter intervals, if spatial data are available. We offer suggestions to guide census design for other elephant populations or cryptic species. We urge that other locations be systematically surveyed as well using photographic identification.
Article
A compilation of data from East and southern Africa is used to establish a relationship between precipitation and peak biomass aboveground in the herb layer (a crude measure of primary production). The regression equation is: peak biomass (kg ha-1) = 8.488 × precipitation (mm) - 195.768, which predicts a peak biomass of approximately 800 kg ha-1 for every 100 mm of precipitation received above 20 mm. The usefulness and limitations of this result are discussed. Une compilation de données d'Afrique du Sud et de l'Est est utilisée pour établir une relation entre la précipitation et la biomasse maximale du tapis herbacé au-dessus du sol (mesure brute de la production primaire). L'équation de régression est: biomass maximale (kg ha-1) = 8,488 × précipitation (mm) - 195,768, qui prédit une biomasse maximale d'environ 80 kg ha-1 pour chaque tranche de 100 mm de précipitation au-delà de 20 mm. L'utilité et les limites de ce résultat sont discutés.
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There are few studies quantifying the productivity of rural pigs and evaluating the nutritive value of non-conventional feeds, such as weeds. The objectives of this study were to determine changes in body condition scores of boars and lactating sows and investigate changes in the chemical composition of commonly used pig feed resources in a smallholder farming area of Zimbabwe. Body condition scores (BCS) were measured monthly between October and April. Commelina benghalensis (wandering jew) and Richardia brasiliensis (Mexican clover) were collected monthly, between October and March, for proximate and amino acid analysis. Sows had lower BCS than boars (P<0.05). The Neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents of C. benghalensis were lower (P<0.05) than those of R. brasiliensis. C. benghalensis had about twice the amount of crude protein (CP) compared to R. brasiliensis. Lysine, methionine and cysteine, which are the most important amino acids in pig nutrition, were similar in groundnut hulls and R. brasiliensis. C. benghalensis had higher (P<0.05) levels of threonine, tryptophan, isoleucine, leucine, histidine, phenylalanine, tyrosine, valine, arginine, serine, aspartic acid, glutamic acid, glycine and alanine than R. brasiliensis. The proportion of essential amino acids (EAA) was significantly higher (P<0.05) in R. brasiliensis. A further study to determine the digestibility and growth performance of pigs fed on these non-conventional diets is needed.
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1. The migratory wildebeest (Connochaetes taurinus (Burchell)) population of Serengeti has been monitored for 40 years (1958–1998). The population increased from 1963 to 1977, stabilized from 1977 to 1993 and declined during drought in 1993–94. These changes provided a significant contrast in densities and the opportunity to determine the life history stages where survival was density dependent and their causes. 2. There was a delay in age of maturity and a decline of both yearling and adult pregnancy rates at higher densities. Changes in yearling pregnancy had minimal effect on number of calves born. Adult pregnancy rate dropped from 95% to 88% 3. The greatest absolute mortality occurred in newborn calves (0–4 months old). The most variable survival was in dry-season calf mortality (5–11 months old). 4. Density dependence was clearly present in adult mortality and this appeared to be the regulating life stage. Density dependence was also found in dry-season calf mortality. The drop in pregnancy rate was only weakly density dependent. 5. The main cause of mortality (75% of cases) was undernutrition. Bone marrow condition showed that more animals died in extremely poor condition as the population increased and predators did not cause these deaths. 6. Predation played only a minor role in limiting the wildebeest population. Predators caught animals in moderate condition during the increase phase and increasingly healthy condition during years of high population density. The main predators were lion [Panthera leo (Linnaeus)] and hyaena (Crocuta crocuta Erxleben). 7. Adult mortality was significantly negatively related to food per capita. This could be viewed either as curvilinear density dependence, or as two phases of mortality. The first phase was during population increase when mortality was inversely density dependent and may have been caused by a constant predation rate. The second was during stability and decline and comprised the additive effects of undernutrition and predation. 8. Rainfall in the dry season was the most important extrinsic determinant of food supply for the wildebeest population but food was related to mortality only when population density was incorporated. 9. At present the wildebeest population appears regulated by natural causes through food supply. Human-caused mortality appears to be a minor factor. However, if the number of wildebeest killed by humans increases as human population increases, then there could be a permanent decline in wildebeest, and a major change in the whole ecosystem, because wildebeest are the keystone species. Continued monitoring is essential for conservation of the Serengeti ecosystem.
Article
A method of assessing body condition of Asian elephants (Elephas maximus) is presented. The method uses visual assessment to assign numerical scores to six different regions of the body, which are totaled to give a numerical index ranging from 0–11. The relationship between the index and morphometric variables is compared for a sample of 119 juvenile and young adult elephants from southern India, Nepal, and Myanmar. Mean ages of males and females were similar. Mean index of body condition (with standard error [SE]) was 7.3±0.2 points. No significant correlation was found between index of body condition and age over both sexes (r=0.01, n=50). Results were equivalent when sexes were treated separately (females: r=0.03, n=24; males: r=0.01, n=26). Sexes did not differ in height of the shoulder or body condition in our sample, but there was significant sexual dimorphism in breadth of the zygomatic arch and three measures of subcutaneous fat: girth of neck, thickness of cervical fold, and thickness of anal flap. These three measures were also significantly correlated with each other. Our assessment method should prove a practical tool for ecologic studies, but the relationship of the index to percentage of body fat should be determined using heavy water dilution methodology. Zoo Biol 25:187–200, 2006. © 2006 Wiley-Liss, Inc.
Article
We report on the genetic evaluation and behavioral study of social organization in the Asian elephant (Elephas maximus). Although Asian elephants and African elephants (Loxodonta africana) were previously thought to have similar social organizations, our results demonstrate a substantial difference in the complexity and structure of Asian elephant social groupings from that described for African savanna elephants. Photographic cataloging of individuals, radio telemetry, and behavioral observations in Ruhuna National Park, Sri Lanka, enabled us to assign associated females and young to four groups with overlapping ranges. Genetic sampling of individuals from the four groups in Ruhuna National Park and three other groups in surrounding areas, conducted through PCR amplification and sequencing of mitochondrial DNA from dung, supported the matriarchal nature of female groups and the lack of inter-group transfer of females. Behaviorally and genetically, the identified social groups were best described as ”family groups”. We did not find any evidence for the existence of social groups of higher complexity than family groups.