No description available.

The movement and distribution of elephants can be influenced by environmental factors over time (Foley, 2002). Examining how features in the landscape such as vegetation productivity, water sources and anthropogenic activities drive the movement of elephants can help in understanding patterns of movement. It can also help to inform the establishment and alignment of protected areas, wildlife corridors and identification of tourism hotspots as well as policy interventions to manage Human-Elephant Conflict (HEC). The Okavango Panhandle in Botswana is a HEC hotspot and the focus of My study. A number of strategies to address HEC are underway in the area, however one longer term strategy that has been proposed in this area involves provision of artificial water sources to influence elephant movements and keep animals away from fields during the cropping season. However, an improved understanding of how elephants utilize their habitats in relation to natural ephemeral surface water and other factors that influence their movements from dryland habitats to the Okavango Delta resources is needed to inform such management decisions. My study seeks to establish the role of ephemeral surface water on elephant distribution in the eastern Okavango Panhandle, Botswana as well as assess the movement distribution of elephants in relation to the seasonality, proximity and spatial extent of water presence represented by ephemeral surface water. Time series analysis of water extent on ephemeral surface water of the eastern Okavango panhandle will be developed and overlaid with elephant movement datasets. Elephant collar data from 15 elephants (5 males and 10 females) in the eastern Okavango Panhandle, Botswana have been analysed and Home Range (HR) sizes estimated using Kernel Density Estimation (KDE). The relative importance/probability of environmental variables in determining elephants' movement based on the Utilization Distribution (UD) were computed using Generalized Linear Mixed Models (GLMMs). I utilized a remote sensing spectral index, namely the Automated Water Extraction Index (AWEI) to delineate ephemeral surface water in dryland (excluding permanent waters) of the study area. The results reveal that during the wet season, elephants were evenly spread out all over the study area until the early dry season (April-June) when the ephemeral waterholes dried up. Elephants moved southwards towards the permanent waters of the Okavango River, where there are many human settlements and farms. Male HR sizes were found to be bigger than those of female elephants. Wet season (early and late) home range sizes were also bigger when compared to dry season (early and late) HR size. Mean daily distances were computed to investigate the effect of season on elephant daily distances and the distances ranged between 5km and 6.8km in the late wet and in the early wet and late dry season respectively. The Resource Selection Function (RSF) analysis shows that water adjacent sites are preferred over distant ones and both sexes prefer areas with high NDVI, with this preference being more pronounced in males. The seasonal variation of water use is notable in that it affirms the importance of proximity to water for elephants and has implications for their management and HEC. For example, I found that ephemeral surface water has a significant role in influencing elephant spatial use in the area, particularly during the early and late wet season. As ephemeral pans dried and NDVI (vegetation greenness) decreased, elephants started to move closer to the Okavango Delta and consequently human settlements and fields. However, further investigations into the timing of movements away from ephemeral waterholes and the influence of other environmental factors on elephant movements in the area would be needed before any recommendations can be made regarding artificial water provision in this area.

No description available.

The Vertebrate Integrative Physiology (VIP) lab monitors the population of northern elephant seals at the largest mainland breeding colony, located at Piedras Blancas (San Simeon, CA). As the population expands, more human-seal interactions and conflicts over land use occur. The VIP lab's work informs California State Parks and helps with the management of the rookery. Currently, members of the VIP lab fly a drone over the beaches, capture multiple images, and manually count the seals, which takes around 14 to 21 hours of analysis per survey. Machine learning methods such as Convolutional Neural Networks (CNN) and Region-based Convolutional Neural Networks (RCNN) have been shown to quickly and accurately determine the count but require lots of data, which is not feasible for this task due to the 79 available beach images. By dividing larger beach images into smaller sub-images, it is possible to generate more data, facilitating the use of deep learning techniques. This thesis outlines a pipeline to use these sub-images and determine the seal count of a beach image.

The present study compared Sand Forest bird assemblages found in a communal land area with that of the Tembe Elephant Park, and determined the habitat preference and status of selected herbivore species within the park. The study forms part of the Maputaland Conservation-based and Integrated Rural Development Programme of the Centre for Wildlife Management from the University of Pretoria and is linked to the activities of the Lubombo Transfrontier Conservation Area (LTFCA). The main purpose of the study was to compare Sand Forest bird assemblages found in the Tshanini Community Conservation Area, which is characterised by low levels of human utilisation, with that of the Tembe Elephant Park, which is characterised by wildlife utilisation. This approach was used to determine the biological importance of this communal land area in contributing towards the conservation of the rare Sand Forest habitat. Visual and auditory bird surveys revealed that the communal land area contains unique Sand Forest bird assemblages, which demonstrated the biological importance of the communal land for Sand Forest conservation, especially from an avian perspective. The second purpose of the study was to identify possible competition between selected herbivore species within the Tembe Elephant Park and/or a decrease in numbers of rare species. Herbivores that might be adversely affected by the destruction of the Sand Forest, or who may themselves have a destructive effect on the Sand Forest were also identified. Target herbivores included the nyala Tragelaphus angasii, impala Aepyceros melampus, Burchell’s zebra Equus burchellii, greater kudu Tragelaphus strepsiceros, red duiker Cephalophus natalensis and suni Neotragus moschatus. Road transects were used to record the spatial distribution of the target herbivores, and the vegetation types that were used more or less often than expected were subsequently determined. None of the target herbivores showed a preference for the Sand Forest or appeared to have a destructive effect on the Sand Forest. The suni, however, reached its highest density within the Sand Forest and the destruction of this habitat will therefore negatively affect the suni population. In several parks and reserves that aim to conserve a variety of species, it has been necessary to control the populations of highly competitive species. Both the nyala and the impala are highly competitive and occur in relatively high numbers within the Tembe Elephant Park, and consequently their population numbers should be kept sufficiently low in order not to have a negative influence on the vegetation or the survival of less competitive ungulates. Total aerial counts and transect distance sampling counts indicated an increase in the numbers of all the target herbivores. It is important to protect a viable portion of the preferred habitat of every target species within a reserve, and to keep competition with rare species to a minimum for the long-term survival of the regional biodiversity. Key aspects of wildlife and their habitat should be monitored so that trends are noted in time, and management adjustments can be made accordingly. / Dissertation (MSc (Wildlife Management))--University of Pretoria, 2007. / Centre for Wildlife Management / unrestricted

Forest elephant (Loxodonta africana cyclotis) sociality is relatively little-studied due to the difficulties of making direct observations in rainforests. In Central Africa elephants aggregate at large natural forest clearings known as bais, which have been postulated to offer social benefits in addition to nutritional resources. This thesis explores the role of these clearings as social arenas by examining bai use within three main themes; ecology, sociality and risk factors. Seasonal changes in elephant use of the Maya Nord bai (Republic of Congo) are described, along with the demography of the visiting population. Elephant visit rate was highly variable; the number of elephants using Maya Nord in an observation day ranged from 0 to 117 animals. This variability was unrelated to local resource availability and productivity suggesting that bai use occurs year round. Elephants in Odzala-Kokoua do not show high fidelity to a single clearing; 454 elephants were individually identified and re-sighted an average of 1.76 times (range 1-10) during the twelve month study period. Previous bai studies have yet to quantify how elephants associate with one another within the bai area. This study examines socio-spatial organisation and associate choice using two measures of association within the 0.23 km2 bai area; aggregations (all elephants present in the clearing) and parties (elephants spatially co-ordinated in activity and movement) and distinguishes these from parties that range together (i.e. arrive and leave together). Social network analyses (SocProg) were used to describe inter- and intra-sexual multi-level organisation in the bai environment, and to illustrate the non-random nature of elephant aggregations and parties. Bais were shown to function as social arenas; female elephants showed active choice of certain associates and active avoidance of others when creating parties, whereas males were less discriminatory. Parties formed in the clearing (mean size= 3.93, SE= 0.186) were larger than ranging parties (mean size= 2.71, SE= 0.084) and elephants stayed for 50% longer in the clearing when they associated with individuals from outside their ranging party. Inter- and intra-sexual relationships were maintained within the clearing, and these are suggested to offer elephants essential opportunities for social learning. The patterning and nature of the relationships observed at the Maya Nord clearing indicates that forest elephants use a fission-fusion social structure similar to that of savannah elephants (Loxodonta africana africana); relationships are significantly structured by age- and sex- and underpinned by individual identity. Old experienced females hold key roles for forest elephants, and male relationships are superimposed on the network of female associations. Odzala-Kokoua elephants use bais to maintain their social relationships despite being highly sensitive to the anthropogenic risks involved in using these open areas. The results of this study suggest that forest and savannah elephants lie on the same social continuum, balancing social “pulls” to aggregate against the ecological “pushes” that force groups to fission. Previous models of savannah elephant sociality construct levels of association and social complexity upwards from the basic mother-calf unit (e.g. Wittemyer & Getz 2007). My results suggest that it may be more appropriate to consider elephant sociality and associations as in dynamic equilibrium between social and ecological influences acting at all levels of grouping, and to explicitly test how these underlie the opportunity costs that elephants are willing to pay in order to maintain social groupings.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirements for the degree of Master of Science. Johannesburg, 2017. / With an increase in opportunistically-collected data, statistical methods that can accommodate unstructured designs are increasingly useful. Spatial capturerecapture (SCR) has such potential, but its applicability for species that are strongly gregarious is uncertain. It assumes that average animal locations are spatially random and independent, which is violated for gregarious species. I used a data set for African elephants (Loxodonta africana) and data simulation to assess bias and precision of SCR population density estimates given violations in location independence. I found that estimates were negatively biased and likely too precise if non-independence was ignored. Encounter heterogeneity models produced more realistic precision but density estimates were positively biased. Lowest bias was achieved by estimating density of groups, group size, and then multiplying to estimate overall population density. Such findings have important implications for the reliability of population density estimates where data are collected by unstructured means. / LG2017

A research report submitted to the Faculty of Science, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Masters of Science (Environmental Sciences). September 2015. / African elephants (Loxodonta africana) are still being poached and hunted and this could potentially affect their movement. As a keystone species, crucial to maintaining ecosystem function and therefore food webs, it is important to understand the effects hunting may have on their movements. This study was undertaken in the Associated Private Nature Reserves adjacent to the Kruger National Park, where elephants are hunted. I looked at changes in daily displacement distance and distance from hunting and natural mortality events to determine if elephants were affected by hunting events, up to what distance, and to determine whether elephants reacted in the same way to hunting and natural mortality events. I found that elephants are only affected by hunting events when within 1 km of the event, which is consistent with the literature. When considering natural mortality events, they actually diverted movements towards the event location, which is also consistent with literature. These results, however, are based on a very small sample size. In addition, the time of day of the events was not recorded by the wardens of the reserve, and this provided a further limitation for the data analysis and interpretation.

Passeio aleatório é uma classe de modelos matemáticos que têm por objetivo descrever processos estocásticos cujo resultado observável é dado por uma soma de variáveis aleatórias. O termo foi cunhado em 1905 pelo estatístico inglês Karl Pearson, estando na época interessado na modelagem da migração de insetos, e hoje possui uma ampla gama de aplicações, indo desde a biologia, passando pela física e química, e chegando na economia. Tendo sido estudado por inúmeros cientistas, muitas variações surgiram, chegando aos passeios aleatórios correlacionados, processos estocásticos não-Markovianos nos quais as variáveis aleatórias que se somam, chamadas de passos, possuem dependências umas com as outras, com correlações de caudas longas. Em 2004, surge na literatura o passeio aleatório do elefante, um passeio aleatório correlacionado com um mecanismo microscópico de memória de longo alcance muito bem definido e com soluções analíticas. Além desses dois fatos, também despertou o interesse da comunidade científica por exibir superdifusão. Muitas variações desse modelo foram propostas e vários resultados foram obtidos nos anos que se seguiram. A presente dissertação contem uma compilação dos principais modelos e resultados da área, tentando ser um texto introdutório ao assunto, focando sempre no que diz respeito à difusão. No caso unidimensional, propomos uma generalização desse tipo de passeio aleatório, o qual envolve decisões probabilísticas com respeito a passos lembrados do passado. Já no caso multi-muldimensional, apresentamos o conceito de acoplamento de memória e o modelo de Vaca e Boi, introduzidos pelo autor deste trabalho em 2018, como uma maneira de incluir interações entre elefantes. Também obtivemos um limite do contínuo para esse último processo, permitindo calcular os regimes de difusão para o Boi e construir um diagrama de fases para o mesmo. Esses últimos pontos constituem as principais contribuições do presente trabalho. / Random walk is a class of mathematical models which has the objective of describing a stochastic process whose observable result is given by a sum of aleatory variables. The term was coined in 1905 by the english statistician Karl Pearson while he was interested in the insects migration modeling, but today it has a myriad of applications, from biology to stock markets, passing through physics and chemestry. It has been studied by an uncountable number of scientists and a lot of variations have appeared, including those called correlated random walks, which are stochastic non-Markovian process in which those random variables that are summed, called steps, depends one of each other with fat tails correlations. In 2004, the elephant random walk appeared in the literature. It is a correlated random walk with a microscopic well defined memory mechanism and that has analitical solutions. Besides these facts, it also arouse the interest of scientific community because it exhibits superdifusion behaviour. In the one-dimensional case, we propose a generalization of this kind of random walk, which involves probabilistic decisions with respect to remembered steps given in the past. In the multi-dimensional case, we present the concept of memory coupling and the Cow and Ox model, which were introduced by the author of this work in 2018 as a manner of including interactions among elephants. We have also obtained a continuum limit of this process, allowing us to calculate the Ox diffusion regimes and to build its phase diagram. These last points constitute the main contributions of the present work.

No presente estudo foram efetuados três ensaios. No primeiro, foram comparados os efeitos de teores crescentes de proteína metabolizável (PM), de acordo com o NRC (2001) para vacas lactantes mantidas em pastagens de capim Elefante. Os aumentos em PM foram obtidos com o aumento da proporção de farelo de soja na ração. Foram utilizadas 12 vacas, delineadas em quadrado latino 3 x 3 com quatro repetições, durante 60 dias de avaliação. Não foi observado efeito (P>0,05) sobre a produção de leite e leite corrigido para 3,5% de gordura, teores e produção de gordura, proteína e sólidos totais. Houve aumento linear (P<0,05) nos teores de nitrogênio uréico no leite (11,17; 13,17; 15,63 mg dL-1) e no plasma (18,57; 19,93; 21,99 mg dL-1). No segundo ensaio, foram avaliados os efeitos de dois diferentes intervalos entre desfolhas (95% de interceptação de luz pelo dossel - T1 e 27 dias fixos - T2) das pastagens de capim Elefante sobre o desempenho lactacional de vacas leiteiras. Foram utilizadas oito vacas lactantes, delineadas em cross-over, durante 80 dias. Os dados das pastagens foram analisados através de delineamento inteiramente casualizado com medidas repetidas no tempo. Foi observado maior (P<0,05) altura do dossel em pré (1,03 e 1,21m) e pós-pastejo (0,62 e 0,71m), interceptação de luz pelo dossel (95,47 e 97,91%), teor de fibra em detergente ácido (35,88 e 37,05%) e fibra em detergente neutro (65,08 e 66,99%). Não houve efeito dos tratamentos (P>0,05) sobre a massa de forragem em pré (6.270 e 6.310 kg de MS ha-1) e pós-pastejo (3.580 e 3.850 kg de MS ha-1). Houve tendência de maior produção de leite (16,72 e 14,09 kg dia-1), produção de gordura (0,64 e 0,54 kg dia-1), lactose (0,72 e 0,58 kg dia-1) e de sólidos totais (2,04 e 1,70 kg dia-1) para o T1 em comparação com o T2. No terceiro estudo, foram avaliados os efeitos de três estratégias de suplementação protéica nas rações (isoprotéicas) com cana-de-açúcar para vacas em lactação, em dois níveis de produção, 18 kg dia-1 (T1, T2 e T3) e 10 kg dia-1 (T4, T5 e T6). No T1 e T4, foi usado o teor de 1 kg de uréia para cada 100 kg de cana-de-açúcar in natura, no T2 e T5 as rações foram formuladas com teores ajustados de PM, enquanto no T3 e T6 havia teores excessivos de PM, conforme o NRC (2001), através do aumento em farelo de soja e redução na uréia. Para a análise dos dados foi utilizado o delineamento em quadrado latino 3 x 3 com três replicações. Não houve efeito dos tratamentos (P>0,05) sobre o consumo de matéria seca, produção de leite, teor de gordura, proteína e sólidos totais. Também não houve efeito dos tratamentos (P>0,05) sobre os teores de nitrogênio uréico no leite (13,42; 13,26; 14,03 e 13,62; 13,48; 14,12 mg dL-1) e no plasma (19,03; 19,22; 20,02 e 19,23; 19,32 e 20,12 mg dL-1), para ambos os grupos avaliados. / In the present study three trials were conducted. Trial 1: Three concentrates with increasing metabolizable protein (MP) contents were fed to lactating dairy cows grazing Elephant grass. Extra soybean meal was fed to increase MP in the diet beyond NRC (2001) recommendation. Twelve cows were used in a 3 x 3 latin square design, replicated four times, for 60 days. There were no effects (P>0.05) of treatments on milk yield, 3,5% fat corrected milk, on fat, protein and total solids contents and yields. Milk urea nitrogen and plasma urea nitrogen concentrations increased linearly (P<0.05)(11.17; 13.17; 15.63 and 18.57; 19.93; 21.99 mg dL-1) with increasing concentrate crude protein content. Trial 2: Two different intervals between defoliation (95% of light interception - T1 and 27 days fixed - T2) of Elephant grass pasture were compared for lactating dairy cows. Eight cows were used in a cross-over design during 80 days. The pasture data were analyzed in a complete random design with time repeated measurements. The sward heights pre-grazing (1.03 and 1.21m), and post-grazing (0.62 and 0.71m), light interception (95.47 and 97.91%), acid detergent fiber (35.88 and 37.05%) and neutral detergent fiber (65.08 and 66.99%) were higher for T2 compared to T1. Forage mass pre-grazing (6270 and 6310 kg DM ha-1) and post-grazing (3580 and 3850 kg DM ha-1) were not affected by treatments (P>0.05). There were tendencies for higher milk yield (16.72 and 14.09 kg day-1), fat yield (0.64 and 0.54 kg day-1), lactose yield (0.72 and 0.58 kg day-1) and total solids yield (2.04 and 1.70 kg day-1) for T1 in comparison with T2. Trial 3: Three strategies for protein adequacy in sugarcane based diets were compared for lactating dairy cows producing 18 kg milk day-1 (T1, T2 and T3), or 10 kg of milk day-1 (T4, T5 and T6). In treatment 1 (T1 and T4) urea was added to the diets in the dose of 1% of sugarcane (as fed), as traditionally done in Brazil. In treatment 2 (T2 and T5), diets were formulated according to NRC (2001) to be adequate in MP. In treatment 3 (T3 and T6), MP was fed in excess of NRC (2001) recommendation. All the three diets were isonitrogenous. Increasing soybean meal and decreasing urea in the diets was done to increase MP. Eighteen dairy cows, separated in two groups (10 and 18 kg milk-1 day-1) with nine cows each, were used during sixty days, in a 3 x 3 latin square design replicated three times. There were not effects of treatments (P>0.05) on DMI, milk yield, fat contents and yields, protein contents and yields and total solids contents and yields. There were not effects of treatments (P>0.05) on milk urea nitrogen (13,42; 13,26; 14,03 e 13,62; 13,48; 14,12 mg dL-1) and plasma urea nitrogen (19.03; 19.22; 20.02 and 19.23; 19.32 e 20.02 mg dL-1).