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- FromFigure 5a,b, it is evident that the suitable habitat regions mapped fell completely within the 5-km buffer zones of water holes in the park for both the dry and the wet seasons. This confirms the importance of water and water availability in the distribution of elephants as demonstrated in publications relating to the niche of elephants (Blake, 2002;Chamaille-Jammes et al., 2007;De Knegt et al., 2011;Harris et al., 2008;Leggett, 2006;Mwambola et al., 2016;Nellemann, Moe, & Rutina, 2002;Ngene, Skidmore, Van Gils, Douglas-Hamilton, & Omondi, 2009;Ngene et al., 2010;Ochieng, 2015;Rood et al., 2010;Shannon, Matthews, Page, Parker, & Smith, 2009;Verlinden & Gavor, 1998). The wet season in MNP is characterized by a large expanse of open Savannah grasses, ensuring there is plenty of vegetation (forage).
[Show abstract] [Hide abstract] ABSTRACT: To avoid unnecessary waste of limited resources and to help prioritize areas for conservation efforts, this study aimed to provide information on habitat use by elephants between the wet and dry seasons in the Mole National Park (MNP) of Ghana. We compiled coordinates of 516 locations of elephants' encounters, 256 for dry season and 260 for wet season. Using nine predictor variables, we modeled the probability of elephant's distribution in MNP. We threshold the models to " suitable " and " nonsuita-ble " regions of habitat use using the equal training sensitivity and specificity values of 0.177 and 0.181 for the dry and wet seasons, respectively. Accuracy assessment of our models revealed a sensitivity score of 0.909 and 0.974, and a specificity of 0.579 and 0.753 for the dry and wet seasons, respectively. A TSS of 0.488 was also recorded for the dry season and 0.727 for the wet season indicating a good model agreement. Our model predicts habitat use to be confined to the southern portion of MNP due to elevation difference and a relatively steep slope that separates the northern regions of the park from the south. Regions of habitat use for the wet season were 856 km 2 and reduced significantly to 547.68 km 2 in the dry season. We observed significant overlap (327.24 km 2) in habitat use regions between the wet and dry seasons (Schoener's D = 0.922 and Hellinger's-based I = 0.991). DEM, proximity to waterholes, and saltlicks were identified as the key variables that contributed to the prediction. We recommend construction of temporal camps in regions of habitat use that are far from the headquarters area for effective management of elephants. Also, an increase in water point's density around the headquarters areas and selected dry areas of the park will further decrease elephant's range and hence a relatively less resource use in monitoring and patrols.- These low frequency vocal signals can carry farther than calls in higher frequency bands, such as trumpets or roars, and therefore may be more useful in communicating over large distances or through thick vegetation that could more easily dampen high frequency signals. Similar vocal signals are frequently used by African forest elephants (Loxodonta cyclotis), which live in the dense rain forests of Central Africa and occupy ranges of up to 2000 km 2 (Blake, 2003;Kolowski et al., 2010). Forest elephants often exhibit coordinated social behaviors, such as synchronized gatherings near resources in forest clearings (Fay, 1995, 2001), which may be made possible by these infrasonic rumbles (Thompson et al., 2010).
[Show abstract] [Hide abstract] ABSTRACT: African forest elephants (Loxodonta cyclotis) occupy large ranges in dense tropical forests and often use far-reaching vocal signals to coordinate social behavior. Elephant populations in Central Africa are in crisis, having declined by more than 60% in the last decade. Methods currently used to monitor these populations are expensive and time-intensive, though acoustic monitoring technology may offer an effective alternative if signals of interest can be efficiently extracted from the sound stream. This paper proposes an automated elephant call detection algorithm that was tested on nearly 4000 h of field recordings collected from five forest clearings in Central Africa, including sites both inside protected areas and in logging concessions. Recordings were obtained in different seasons, years, and under diverse weather conditions. The detector achieved an 83.2% true positive rate when the false positive rate is 5.5% (approximately 20 false positives per hour). These results suggest that this algorithm can enable analysis of long-term recording datasets or facilitate near-real-time monitoring of elephants in a wide range of settings and conditions.- FromFigure 5a,b, it is evident that the suitable habitat regions mapped fell completely within the 5-km buffer zones of water holes in the park for both the dry and the wet seasons. This confirms the importance of water and water availability in the distribution of elephants as demonstrated in publications relating to the niche of elephants (Blake, 2002;Chamaille-Jammes et al., 2007;De Knegt et al., 2011;Harris et al., 2008;Leggett, 2006;Mwambola et al., 2016;Nellemann, Moe, & Rutina, 2002;Ngene, Skidmore, Van Gils, Douglas-Hamilton, & Omondi, 2009;Ngene et al., 2010;Ochieng, 2015;Rood et al., 2010;Shannon, Matthews, Page, Parker, & Smith, 2009;Verlinden & Gavor, 1998). The wet season in MNP is characterized by a large expanse of open Savannah grasses, ensuring there is plenty of vegetation (forage).
[Show abstract] [Hide abstract] ABSTRACT: To avoid unnecessary waste of limited resources and to help prioritize areas for conservation efforts, this study aimed to provide information on habitat use by elephants between the wet and dry seasons in the Mole National Park (MNP) of Ghana. We compiled coordinates of 516 locations of elephants' encounters, 256 for dry season and 260 for wet season. Using nine predictor variables, we modeled the probability of elephant's distribution in MNP. We threshold the models to " suitable " and " nonsuita-ble " regions of habitat use using the equal training sensitivity and specificity values of 0.177 and 0.181 for the dry and wet seasons, respectively. Accuracy assessment of our models revealed a sensitivity score of 0.909 and 0.974, and a specificity of 0.579 and 0.753 for the dry and wet seasons, respectively. A TSS of 0.488 was also recorded for the dry season and 0.727 for the wet season indicating a good model agreement. Our model predicts habitat use to be confined to the southern portion of MNP due to elevation difference and a relatively steep slope that separates the northern regions of the park from the south. Regions of habitat use for the wet season were 856 km 2 and reduced significantly to 547.68 km 2 in the dry season. We observed significant overlap (327.24 km 2) in habitat use regions between the wet and dry seasons (Schoener's D = 0.922 and Hellinger's-based I = 0.991). DEM, proximity to waterholes, and saltlicks were identified as the key variables that contributed to the prediction. We recommend construction of temporal camps in regions of habitat use that are far from the headquarters area for effective management of elephants. Also, an increase in water point's density around the headquarters areas and selected dry areas of the park will further decrease elephant's range and hence a relatively less resource use in monitoring and patrols.- Hence, the range of plant species consumed by elephants varies greatly across geographic regions as do their daily travel and, therefore, potential seed dispersal distances (Sukumar 1989). Forest elephants in Ivory Coast have been reported to cover 1e15 km/ day, for an average of about 6 km/day (Theuerkauf and Ellenberg, 2000) whilst in northern Congo their travel distance varied between 2 and 22 km/day (Blake, 2002). However, the actual distances over which elephants can disperse seeds can be much larger, especially for large seeds, which can take several days to pass through the digestive tract (Powell, 1997).
[Show abstract] [Hide abstract] ABSTRACT: Elephants, the largest terrestrial mega-herbivores, play an important ecological role in maintaining forest ecosystem diversity. While several plant species strongly rely on African elephants (Loxodonta africana; L. cyclotis) as seed dispersers, little is known about the dispersal potential of Asian elephants (Elephas maximus). We examined the effects of elephant fruit consumption on potential seed dispersal using the example of a tree species with mega-faunal characteristics, Dillenia indica L., in Thailand. We conducted feeding trials with Asian elephants to quantify seed survival and gut passage times (GPT). In total, 1200 ingested and non-ingested control seeds were planted in soil and in elephant dung to quantify differences in germination rates in terms of GPT and dung treatment. We used survival analysis as a novel approach to account for the right-censored nature of the data obtained from germination experiments. The average seed survival rate was 79% and the mean GPT was 35 h. The minimum and maximum GPT were 20 h and 72 h, respectively. Ingested seeds were significantly more likely to germinate and to do so earlier than non-ingested control seeds (P = 0.0002). Seeds with the longest GPT displayed the highest germination success over time. Unexpectedly, seeds planted with dung had longer germination times than those planted without. We conclude that D. indica does not solely depend on but benefits from dispersal by elephants. The declining numbers of these mega-faunal seed dispersers might, therefore, have long-term negative consequences for the recruitment and dispersal dynamics of populations of certain tree species.- This is one of the few quantitative analyses of wild elephant food habits in tropical rainforest environments of Southeast Asia (see also Olivier 1978; English et al. 2014a English et al. , 2014b) and to our knowledge the first to use dung microhistological analysis to identify diet contents. Forest elephants have the most diverse diets of any wild herbivores (Blake 2002). Since direct observation of wild elephant feeding is difficult in tropical rainforest, previous studies have generally relied on indirect observation of feeding signs (e.g., English et al. 2014aEnglish et al. , 2014b).
- It is more likely that these reproductive rates simply reflect the ecological limitations of being terrestrial and (at least partially) reliant on fruit in primary tropical forest areas. Although the forest environment is dense in vegetal matter, much of forest elephant diet consists of browse (leaf matter and bark; White 1994; Blake 2002) which is high in secondary compounds and low in quality (Coley & Barone 1996). Low reproductive rates may in fact be the norm for large-bodied mammals in these rain forests (Tutin 2001).
Slow intrinsic growth rate in forest elephants indicates recovery from poaching will require decades
[Show abstract] [Hide abstract] ABSTRACT: African forest elephants Loxodonta cyclotis are experiencing persistent declines driven by illegal killing and range loss. Despite the importance for policy debates regarding elephant trade managed through the Convention on International Trade in Endangered Species (CITES), little is known about forest elephant demography and, consequently, the impacts of offtake and subsequent population recovery potential. Using 23 years of individually based demographic data from Dzanga, Central African Republic, we found low reproductive potential resulting from annual birth rates averaging 4·3% (SD: 1·4%), a median inter-birth interval of 68 months and a median primiparous age of 23 years. Average mortality was 3·1% per year (SD: 1·0%) during the study, with approximately 1·4% of that attributed to human killing. This population of forest elephants demonstrated concerningly slow growth rates, with a doubling time of nearly 60 years under current conditions (41 years excluding human impacts), amounting to three times that reported for savanna elephants. As such, forest elephants appear to be significantly more sensitive to human-induced mortality than their congeneric species. Such slow intrinsic growth challenges current perceptions of historic and contemporary ivory trade impacts on forest elephants, highlighting the urgent need to stem poaching and institute long-term protective measures. Policy implications. Debates regarding the sustainability of the ivory trade for the species appear to have overestimated growth rates of forest elephants. The information presented here indicates that sustainable offtake models for forest elephants need reassessment.
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