Search

Ecosystem and livelihood sustainability of small-scale farmers in Eastern Africa are often challenged by climate change and unsustainable land use practices. Little is known on the small-scale temporal processes of cropping systems in relation to long-term climatic conditions. To understand the climatic influence on the cropping patterns, and its implications to wildlife/elephant conservation, our study used a combination of time-series datasets on crop and climate as well as geo-spatial layers spanning more than three decades. To validate the information analyzed from secondary data, we carried out participatory observation and interviews, whereby about 5% of village households were selected along an altitudinal gradient of Rombo area, Tanzania. We generated land use change maps using Geographical Information System (ArcGIS 10.4) and used Spearman's correlation analysis to assess the influence of rainfall, temperature, and crop yield on the observed longitudinal changes in the crop types and other land use patterns both within and across altitudinal gradients. We found that perennial crops like coffee and banana concentrated in upper agro-ecological zones, with a clear division line above 1230 masl while seasonal crops like maize and beans were mostly cultivated in lowlands (below 1230 masl). The results further showed that coffee yields significantly declined with higher average annual minimum temperatures over the last 16 years. Within the same time period, there was a disproportionate shift from coffee to seasonal crop cultivation such as maize and beans. Elephant numbers declined by about 38%, while human settlement area increased by 28% over the last 30 years. We conclude that changes in land use and shifts in climate and cropping patterns have important implications for elephant conservation and sustainability of the ecosystem in Rombo area, Tanzania.

While spontaneous yawning is common across all vertebrate classes, contagious yawning is less common and has been observed only in a few species of social animals. Interspecific contagious yawning in response to yawning by humans has been observed only by chimpanzees and dogs. After confirming additional occurrences of intraspecific contagious yawning in a group of captive African elephants previously studied, we further investigated the potential for the same group of elephants to engage in interspecific contagious yawning with familiar human handlers. Ten captive African elephants, most of whom had been previously studied, were observed over 13 nights for evidence of intraspecific contagious yawning. Seven of these elephants were also involved in trials where familiar handlers performed staged yawns, as well as trials with staged non-yawning gapes, or trials with no yawns or gapes. Incorporating previously collected contagious yawning data, we describe nine instances of intraspecific contagious yawning in the elephants. Three of the seven elephants yawned contagiously in response to humans during the interspecific yawning trials. This is the first report of interspecific contagious yawning by elephants in response to yawns by familiar humans.

While spontaneous yawning is common across all vertebrate classes, contagious yawning is less common and has been observed only in a few species of social animals. Interspecific contagious yawning in response to yawning by humans has been observed only by chimpanzees and dogs. After confirming additional occurrences of intraspecific contagious yawning in a group of captive African elephants previously studied, we further investigated the potential for the same group of elephants to engage in interspecific contagious yawning with familiar human handlers. Ten captive African elephants, most of whom had been previously studied, were observed over 13 nights for evidence of intraspecific contagious yawning. Seven of these elephants were also involved in trials where familiar handlers performed staged yawns, as well as trials with staged non-yawning gapes, or trials with no yawns or gapes. Incorporating previously collected contagious yawning data, we describe nine instances of intraspecific contagious yawning in the elephants. Three of the seven elephants yawned contagiously in response to humans during the interspecific yawning trials. This is the first report of interspecific contagious yawning by elephants in response to yawns by familiar humans.

Rangelands cover about half of Earth's land surface, encompass considerable biodiversity, and provide pivotal ecosystem services. However, rangelands across the globe face degradation due to changes in climate, land use, and management. Moreover, since herbivory is fundamental to rangeland ecosystem dynamics, shifts in the distribution of herbivores lead to overgrazing and desertification. To better understand, predict, and prevent changes on rangelands it is important to monitor these landscapes in a timely and efficient manner. Remote sensing can be a viable tool for measuring such change. However, the high spatial and temporal variability of rangeland vegetation, high reflectance from soil background and senesced vegetation during prolonged parts of the year, present challenges to the application of remote sensing in these ecosystems. The goal of my dissertation is to address these challenges and advance the application of remote sensing and geographic information system (GIS) to quantify vegetation and herbivores on rangelands across the world. My dissertation aims to address the connections among three main components of rangelands: the landscape, herbivores and human factors. I first develop a method to characterize the rangeland landscape by measuring and mapping detailed vegetation variables in Etosha National Park, Namibia. Etosha is a 22,270 km2 semiarid savanna, which encompasses great diversity of flora and fauna. I then examine how landscape variables affect the movement patterns of a large mammalian herbivore that is a keystone species in Etosha, the African elephant (Loxodanta africana). Finally, I develop tools to monitor how herbivory affects the productivity of rangelands conservation easement in California. In the first chapter, I outline the importance of rangelands and the threats these ecosystems face. I review the main challenges of measuring change processes on rangelands and describe some of the remote sensing based approaches that have been

Rangelands cover about half of Earth's land surface, encompass considerable biodiversity, and provide pivotal ecosystem services. However, rangelands across the globe face degradation due to changes in climate, land use, and management. Moreover, since herbivory is fundamental to rangeland ecosystem dynamics, shifts in the distribution of herbivores lead to overgrazing and desertification. To better understand, predict, and prevent changes on rangelands it is important to monitor these landscapes in a timely and efficient manner. Remote sensing can be a viable tool for measuring such change. However, the high spatial and temporal variability of rangeland vegetation, high reflectance from soil background and senesced vegetation during prolonged parts of the year, present challenges to the application of remote sensing in these ecosystems. The goal of my dissertation is to address these challenges and advance the application of remote sensing and geographic information system (GIS) to quantify vegetation and herbivores on rangelands across the world. My dissertation aims to address the connections among three main components of rangelands: the landscape, herbivores and human factors. I first develop a method to characterize the rangeland landscape by measuring and mapping detailed vegetation variables in Etosha National Park, Namibia. Etosha is a 22,270 km2 semiarid savanna, which encompasses great diversity of flora and fauna. I then examine how landscape variables affect the movement patterns of a large mammalian herbivore that is a keystone species in Etosha, the African elephant (Loxodanta africana). Finally, I develop tools to monitor how herbivory affects the productivity of rangelands conservation easement in California. In the first chapter, I outline the importance of rangelands and the threats these ecosystems face. I review the main challenges of measuring change processes on rangelands and describe some of the remote sensing based approaches that have been

This study assessed the status of woody vegetation structure and composition in two Important Bird Areas (IBA) i.e. Manjinji Pan and Save-Runde Junction located in southeastern Zimbabwe. The objectives of this study were to: (i) determine the woody vegetation structure and composition of the study areas and (ii) find out any differences and similarities in woody vegetation between the two IBAs. Data about woody vegetation were collected from 40 randomly placed sample plots from both study areas. Tree density was higher in Manjinji Pan IBA (406.67 +/- 16.86 trees ha(-1)) than Save-Runde Junction IBA (275.83 +/- 17.62 trees ha(-1)). In contrast, Save-Runde Junction IBA had higher numbers of stems per plant (2.88 +/- 0.22), species richness (59) and diversity (H' = 3.28) than Manjinji Pan IBA: numbers of stems per plant (2.16 +/- 0.12), species richness (43) and diversity (H' = 2.90). No significant differences were recorded in woody plant height, shrub and dead plant densities. The findings suggest that several factors including fires, herbivory and human activities could be influencing the woody vegetation in the two IBAs. However, further research is suggested to better understand the drivers of woody vegetation variation in IBAs occurring in savanna ecosystems. It is recommended that species richness and diversity of woody plants should be maintained and invasive plant species controlled for the conservation of endemic and migratory avifauna.

African elephants (Loxodonta africana) are ecosystem engineers that have the ability to alter the physical structure of the landscape it inhabits and subsequently affect the livelihood of other local species. This study evaluated the landscape and plant level impacts by elephants by means of fallen trees in the Karoo ecosystem. Fourteen transects were walked and found the proportion of fallen trees inside the Kuzuko section of the Addo Elephant National Park was higher than outside the game reserve. Potential shoot bites were higher for standing trees than fallen trees but percentage cover of coppiced re-growth remained similar for all fallen treatments except the Dead treatment. Standing trees were especially important as nurse plants, having a higher density of woody saplings and forbs coverage. Average foliage surface area from the canopy was better than foliage collected from coppiced re-growth outside the reserve. There was a noticeable effect from elephant presence. My data showed that both forage availability and quality decreased from a standing to a fallen tree. However, additional studies should be conducted for a better understanding of foliage quality differences.

Wildlife management is an important area of conservation and has become a priority for many countries and organisations around the world. One of the fundamental components of a sound wildlife management plan is a good understanding of a species’ behaviour and habitat. For animals within inaccessible environments, satellite tracking provides a powerful tool for revealing information on animal movements and their habitat requirements. In this dissertation, the conservation benefits and technical effectiveness of satellite tracking are examined through four case studies representing a diverse range of threatened species studied for periods between six months and five years. The studies revealed important ecological insights on the in situ movement and behaviour of the African elephant (Loxodonta africana), Kruger National Park, South Africa; the New Zealand bush falcon (Falco novaeseelandiae), Central North Island, New Zealand; the estuarine crocodile (Crocodylus porosus), Darwin, Australia; and the northern royal albatross (Diomedea sanfordi), Taiaroa Head, New Zealand and Chile. For each of these studies, satellite telemetry provided location data enabling analyses of the animals’ movements and home ranges, and these analyses inform specific management recommendations. For example, the long time series study on African elephants highlighted the importance of developing reciprocal animal management policies where cross-boundary movements of animals occurred between adjacent parks. The strengths and weaknesses of different satellite tracking systems are compared and guidelines developed to assist wildlife managers in selecting the best technology to suit their research needs. An assessment of the trade-offs between the technical features built into transmitters and the associated cost is also presented. The study shows how the use of satellite tracking systems provides conservation agencies with a better understanding of wildlife behaviour and strengthens their ability

Crop raiding by elephants is a serious management problem around protected areas in Kenya. This is because of changes in the land use systems in these areas, with crop farming occurring in areas where it did not previously. Crop raiding by elephants was monitored in the area adjacent to Marsabit National Park and Reserve between August 2004 and July 2005 (excluding December 2004 and April 2005 due to rains). A total of 414 farms were raided, with the farmers loosing KES 15,034,610 (USD 208,814) during the period. Crop raiding was higher in August 2005 (KES 5,598,660 or USD 77,759) than in August 2004 (KES 503,960 or USD 6999). Tribal clashes in August 2005 contributed to unguarded farms and consequently elephants were presented with an opportunity to raid. The situation was peaceful in August 2004 and farmers had adequate time to guard their farms using scaring strategies to keep elephants away. There is an urgent need to revive the collapsed fence project in order to reduce the cost incurred by farmers due to elephants raiding their crops.

The aim of this study was to better understand how environmental geochemistry influences mineral provision to African savanna elephants, and thus their home range size and movement choices. Due to increasing human activity and competition for land-use, African savanna elephants globally are constrained into smaller areas. This presents elephants with nutritional challenges, requiring adaptation to their movement patterns to obtain sufficient mineral intake. An in situ experiment was enabled by the Palabora Mining Company (PMC) property, and the surrounding national park lands in South Africa, providing a case study of contrasting environments. The PMC mines copper, phosphates and other minerals and the locale is proposed to act as a micronutrient hotspot for elephants, due to its unique local geochemistry. The increased presence of elephants at the PMC, and incursion to the mine with associated disruption of mining activities has resulted in human-elephant conflict. It was hypothesised that elephants reside within the locality of the PMC property, owing to its potential as a micronutrient hotspot. To determine the influence of geochemistry on elephant movement, optimum bioindicators of mineral nutritional or potentially toxic element (PTE) status were required, prior to studying the PMC associated elephant populations, to differentiate between patterns of movement between national park lands and surrounding reserves (background) and mineral processed lands at the PMC (elevated). The validation of optimum bioindicators (e.g. toenail, tail hair, plasma or faeces) for mineral or PTE status was achieved by collection and elemental analyses of environmental and biological samples from 21 elephants at five UK zoos. A linear mixed model showed that toenail was the best bioindicator of intake for Mg, P, K, Se and As, with keeper-fed diet being the strongest predictor (P < 0.05 for all). Tail hair reflected As and Fe intake (P<0.001, 0.029), and Ca intake was reflected in fa

Adiposity is linked to reproductive efficiency as adipose tissue (AT) is known to influence the hypothalamic-pituitary-gonadal axis, although the exact roles of AT remain poorly understood. Different cattle and pig breeds exhibit different adiposity and reproductive characteristics. The hypothesis is that differences in adiposity underpin the phenotypic differences in reproductive performance in these animals. To test this hypothesis, next generation RNA sequencing analysis was completed of AT from (i) cattle (Holstein, Hereford and Aberdeen Angus cross breeds enrolled in a dietary protein feed trial), (ii) European Large White and Asian Meishan pigs and (iii) African elephants. Differentially expressed genes (DEG) were determined in each species and validation completed utilising quantitative reverse transcriptase PCR (qRT-PCR). Results revealed significant DEG involved in adipogenesis and lipogenesis between (i) breeds, (ii) resulting from the dietary protein intervention and (iii) sexes and age groups. Fatty acid (FA) composition of AT from different cattle breeds and dietary protein levels was determined using gas chromatography and compared, although significant difference was not observed. Gene networks related to vitamins A and D suggest potential nutritional influences on adipogenesis and lipogenesis, consequently vitamin levels in feed may impact adiposity and thereby animal reproductive performance. Results from the elephants indicated disparity in energy storage and utilisation between sexes and age groups, thus this can provide baseline information to improve captive population management of these animals in different life stages. By exploiting comparative inferences from previous human and animal studies to the results obtained from this study, a positive influence of adiposity on fertility was identified. Future work should verify whether differential mRNA expression of genes of interest identified are reflected in protein expression. Also additional s