Extensive drought - and elephant-related dieback of Colophospermum mopane and Acacia tortitis, respectively, offered an opportunity for increasing understanding of the causes of drought-related patch dieback, the factors influencing elephant utilization of woody plants, and the response of woody plants to both aforementioned determinants of savanna structure and function. The dendrochronological analysis of both species was undertaken to estimate potential rates of replacement, following extensive mortality. Areas of discrete dieback were compared with adjacent paired areas of 'healthy' vegetation, which revealed, on average, 87% and 13% loss of basal area by mortality, respectively. 'Live' and 'dead' plots did not differ in soil type, topography or mean slope, but differed in vegetation structure, soil surface condition, and soil chemistry. Although there was evidence of self-thinning, neither inter - nor intra-specific competition explained dieback. 'Dead', by comparison with 'live' plots, had changed from functioning as sinks of sediment and water to sources, were less likely to retain water because of a poor soil surface condition, and were predisposed to drought effects because of a greater proportion of fines, and Na concentration. Dieback resulted from insufficient soil water for survival during a drought owing to the development of a dysfunctional landscape during 50 years of livestock ranching. Spatial heterogeneity within a landscape was suggested to enhance woodland resilience to severe droughts by ensuring the survival of plants in run-on sinks or 'drought refuge' sites. Stem sections were removed from 40 multi-stemmed C. mopane trees and prepared for examination under a dissecting microscope. It was impossible to age C. mopane, owing to a hollow and/or dark heartwood. Nevertheless, the distribution of stem diameters suggested a single recruitment event. Fire scars attributed to the last recorded fire in 1948 could explain the trees' multi-stemmed growth form and indicate that most trees of VLNR were > 50 years of age. Growth rings were identified in 29 A. tortilis trees of unknown age, but were not correlated with annual rainfall records. Growth rates varied between trees; mean ring width ranged from 1.4 to 3.5 mm (overall mean 2.4 ± 0.1 mm). A technique was proposed for predicting growth rate from annual rainfall, using selected data, and several factors potentially influencing ring width in semiarid environs were identified. Permanent ground-based transects were located within riparian (n = 16) and Acacia (n = 5) woodlands to monitor elephant utilization. Elephant had not changed the population structure of the woodlands by 2000, but had reduced stem density from 215.6 stems ha -1 (1996) to 84.4 stems ha -I (2000). Acacia tortitis trees in the woodlands had branches removed, were debarked, uprooted and broken. Acacia tortitis trees in the riverine had lower levels of utilization, whilst Acacia nilotica trees were mostly debarked. The method of elephant feeding varies within and between woody species, provided it is within the mechanical constraints of a certain size or species. Elephant behaviour is concluded to depend on spatiotemporal variation of forage abundance/quality, abundance of a preferred species, and species response (coppice or mortality). Elephant can cause a change of vegetation state, and increase spatial homogeneity of a plant population. The remnant population of woodland trees should provide the potential for recolonization, in which case the system would reflect the stable limit cycle. However, if browsing inhibits seedling recruitment, the system could reflect either a multiple stable state system or an artificial equilibrium imposed on a stable limit cycle. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2000.

Im Zuge systematisch durchgeführter thermografischer Untersuchungen an 95 Asiatischen Elefanten in europäischen Zoos konnten physiologische Wärmeprofile aller nicht von Fußkrankheiten betroffener Elefanten erstellt werden. Um eine objektivere Befundung zu ermöglichen, wurden dafür definierte Messbereiche an den Füßen festgelegt und deren Temperaturdaten als Wärmekurven für jeden Zeh dargestellt. Es zeigte sich, dass die Bandbreite von Temperaturen gleicher Messbereiche starken individuellen Schwankungen unterliegt, weshalb eine Befundung nicht anhand absoluter Temperaturwerte erfolgen sollte. So wurden über gleichen Messbereichen unterschiedlicher Elefanten Temperaturunterschiede von bis zu 8 °C festgestellt. Auch die Umgebungsfaktoren während der Untersuchung tragen zu dieser Varianz bei. Bei Umgebungstemperaturen zwischen 17,5 °C und 23 °C stellt sich durch Erhöhung der Außentemperatur um 1 °C eine um 0,5 °C erhöhte Wärmeabstrahlung über der Haut dar. Eine Erhöhung der Luftfeuchte um 1 % verursacht eine um 0,03 °C vermehrte Wärmeabstrahlung. Die Wärmeprofile stellten sich für die Kronsaum- und Hufwandbereiche der Zehen eines Fußes von medial nach lateral in einem parabelförmigen Verlauf dar, wobei die höchsten Temperaturen an den kranialen Zehen gemessen wurden. Die Differenz zwischen Kronsaum- und Hufwandbereichen blieb dabei konstant. Die Temperaturen der Zehenregion oberhalb des Kronsaums folgten nicht dieser Parabelform, lagen aber, außer an der jeweils medialen Seite, konstant unterhalb der Kronsaumtemperaturen. Bei Vergleich mit thermografischen Befunden erkrankter Zehen zeigte sich meist ein starker Anstieg der Zehenregiontemperatur weit über die Kronsaumtemperaturen hinaus, weshalb sich dieses Verhältnis als Indiz für ein akutes Enzündungsgeschehen nutzen lässt. Ein gleichmäßiges Wärmeprofil, welches möglichst dicht dem in dieser Arbeit entwickelten Profil gleicht und konstante Temperaturdifferenzen zwischen den einzelnen Messbereichen aufweist, ist ein gutes Indiz für einen gesunden Fuß. Thermografische Befundungen sollten immer mit Hilfe herkömmlicher visueller Auswertung und zusätzlich der Erstellung eines Wärmeprofils vorgenommen werden, um die Subjektivität zu minimieren. Erstmalig wurden in dieser Arbeit drei Elefanten mittels Pedografie untersucht, um Aufschlüsse über die Druckverteilung unter dem Elefantenfuß zu erhalten. Wie bei Menschen und pedografisch vermessenen Rindern fanden sich auch beim Elefanten charakteristische Druckprofile. Druckspitzenwerte tauchten hierbei vor allem im kranialen Bereich der Füße als Druckleiste, aber auch im kaudalen Bereich in Form zweier Druckpfeiler auf. Experimente mit einer Methode zur Simulierung weicheren Untergrundes schienen die Druckspitzenwerte etwas abzuschwächen und das allgemeine Druckprofil einzuebnen, waren aber nur schwer auszuwerten. Die Methode eignet sich ebenso zur Erfassung der tatsächlich belasteten Fläche der Füße, welche sich bei stärkerer Belastung, beispielsweise dreibeinigem Stehen, vergrößerte. Trotz noch einiger methodischer und technischer Probleme, eröffnet sich mit der Pedografie ein sicherlich lohnenswertes Forschungsfeld für weitere Studien, die einen besseren Einblick in die Druckphysiologie des Elefantenfußes gewähren könnten. Weiterhin wurden in dieser Arbeit Daten der Elefantenhaltungssysteme von 17 besuchten europäischen Zoos, sowie Daten über Häufigkeit und Art der Gliedmaßenkrankheiten und anderer gesundheitlicher Parameter aller 95 untersuchter Elefanten ausgewertet. Hierbei zeigte sich immer noch starker Verbesserungsbedarf im Hinblick auf Innengehegegrößen und die verwendeten Bodenmaterialien. Auch Bewegungsprogramme für den Aufenthalt im Außengehege wurden nur in weniger als der Hälfte der Zoos eingesetzt. Positiv fiel auf, dass die Elefanten in den besuchten Zoos kaum noch angekettet werden und falls doch, nur kurzzeitig zu Untersuchungszwecken. Den Daten der Haltungsanalysen entsprechend, fielen die Auswertungen zur Fußgesundheit aus: Nur 36 % der untersuchten Elefanten litten bisher noch niemals unter Fußerkrankungen. Allein zum Zeitpunkt der Untersuchung wurden bei 27 % der Tiere akute Erkrankungen festgestellt, die unter Behandlung standen. Hierbei handelte es sich hauptsächlich um Abszesse oder andere entzündliche Veränderungen im Bereich des Nagelbetts. Weiterhin wurden 30 % der Elefanten als übergewichtig eingeschätzt und 36 % der Tiere zeigten stereotype Bewegungsmuster. / A total of 95 Asiatic Elephants in 17 European zoos were systematically examined using a high resolution thermographic camera and physiologic heat profiles of elephant’s feet without known foot diseases were established. To allow a more objective evaluation of thermographic findings, the feet and toes were divided schematically into defined areas for measurement purposes, based on anatomical features for which the temperature data was then plotted to produce heat curves for each area. Measurements of temperatures pertaining to similar areas of different elephants showed strong individual fluctuation. Temperature variation was as high as 8 °C in similar areas between elephants. Thus, evaluation of thermographic findings should never be based on absolute temperature readings alone. This strong variation is partly caused by environmental factors during the examination. With environmental temperatures between 17,5 °C and 23 °C, a one degree increase of this temperature will cause a 0,5 °C increase of the heat radiation of the feet. An increase of air humidity by 1 % will cause an increase of 0,03 °C of the measured thermographical heat radiation. The physiological heat profiles for coronary and hoof wall areas of the toes showed an arched, parable-like shape when plotted from the medial over the cranial to the lateral toes. The highest temperature readings were found on the cranial toes. The difference between coronary and hoof wall temperatures of similar toes were constant all over the foot. The physiological heat profiles of the toe areas above the coronary region did not show this arched shape but stayed below the coronary temperature readings except on the medial toe. On comparison with thermographic findings of inflammated toes, a strong increase of this area above the coronary band was found which exceeded the temperature of the coronary region. This characteristic can be used as an indicator for acute inflammations. A regular heat profile, which resembles closely the physiological heat profile created in this study and which shows constant temperature differences between the defined areas of the single toes, is a good indicator of healthy foot. It is recommended that thermographic examinations always are evaluated using conventional observation of the heat patterns in conjunction with the additional creation of a heat profile to minimize subjectivity by the clinician. For the first time three elephants were examined in this study using a new pedographic method to gain information on the pressure distribution below the elephant’s foot. As found in humans as well as in pedographically examined cows, the pressure distribution in elephant’s feet showed a characteristic profile. Pressure peaks showed up especially in the cranial area of the foot, possibly the border between sole and pad, as well as in the caudal region in the shape of two pressure pillars. Experiments with a method to simulate softer ground seemed to lower the pressure peaks slightly in favor of a broader distribution, but were very difficult to evaluate, especially considering the small sample size. This method is also suited to register the actual area size put under pressure by the elephant, which was shown to rise under increased pressure, e. g. three legged standing. Despite some encountered methodical and technical problems, pedography of elephants is going to be a very promising field for further scientific studies in order to acquire more information on the physiology of pressure distribution. Data on husbandry conditions of the 17 visited zoos and as well as data on frequency and type of foot diseases and other health parameters of all 95 examined elephants were also collected and evaluated. A strong need for improvement was observed in terms of enclosure sizes and the surface materials used in indoor enclosures. Also, daily routines to increase activity of the elephants in the outdoor enclosures were found to be carried out only in half of the visited zoos. On a positive note, elephants in the evaluated zoos were hardly ever chained and if so, only for examination purposes. According to the data of the husbandry evaluation the information on the current status of foot health showed the need for improvement: Only in 36 % of the examined elephants foot problems were so far not encountered. On the time of examination 27 % of the animals were found to be under ongoing treatment for foot diseases. Mostly these were abscesses or other inflammation processes in the area of the nail’s laminar tissue. Out of the study sample, 30 % of the elephants were estimated to be overweight and 36 % showed stereotypic movement patterns.

Salivary cortisol is becoming an effective method with which to quantify cortisol levels, including the ability to track diurnal patterns and acute stress fluctuations. The purpose of this study was to validate salivary cortisol for use in African elephants (Loxodonta Africana), establish baseline cortisol values in three African elephants at Zoo Atlanta and explore the relationship between cortisol and various behaviors and husbandry events. Elephant salivary cortisol was found to be a valid measure based on correlations with serum cortisol and serial dilution results. Salivary cortisol also decreased across the day, but no definitive patterns were revealed. Using baseline values, salivary cortisol was used to examine the effects of enrichment, maintenance and novel training, and a mild stressor. Maintenance training was found to lead to lower cortisol values than novel training. Salivary cortisol after enrichment did not differ from individual overall means. The mild stressor initiated a rise in salivary cortisol. The final focus of this study was to investigate the link between salivary cortisol and stereotypic behavior. Stereotypies are described as repetitive behaviors with little variance and no discernible function or goal. There is not a straightforward relationship between stereotypies and welfare. Analysis of salivary cortisol at various durations into swaying bouts established that swaying appears to decrease cortisol levels. Additionally, behavioral data were collected. Behavioral data confirmed anecdotal reports of circular dominance in these animals. Behavioral data also revealed that although these individuals spend the majority of their time consuming food, one individual in particular devotes a significant amount of her time to swaying, a percentage much higher than that found when Wilson, Bloomsmith, and Maple (2004) examined stereotypic swaying rates in these same animals. Results of this study have direct ramifications for the current management requirements for captive elephants around the world. It helps tap into aspects of psychological well being of captive elephants to elucidate factors influencing welfare and stereotypic behavior. Research of this nature is a critical endeavor if we are to appropriately manage these magnificent animals in captivity.

African savanna elephants (Loxodonta africana) and Asian elephants (Elephas maximus) are a focus of welfare research in zoos due to their high intelligence, complex social structure, and sheer size. Due to these challenges, some argue that zoos are inherently incapable of providing appropriate care for elephants, while others believe that zoos can fulfill the needs of these species with improved husbandry. There is a general consensus from both within and outside of zoos, however, that zoos must improve their elephant programs or cease exhibiting these animals altogether. Now more than ever, applied research on zoo elephant welfare is needed to provide context for this debate. Researchers are interested in how far zoo elephants walk due to the potential health and welfare benefits of walking in these highly mobile species. Zoo researchers recently adopted GPS technology to study elephant walking, and preliminary evidence suggests that African elephants in large zoo exhibits walk distances that correspond with wild elephants under non-extreme conditions. However, data are limited from Asian elephants and from elephants in more typically-sized exhibits. In Chapter Two, I discuss important methodological considerations of utilizing GPS in a zoo environment, including an introduction to the technology, sources of error and mitigation, methods to improve GPS performance, and possible effects of GPS device attachment on animal behavior. This review shows GPS performance is adequate for tracking zoo elephant walking when proper methodological techniques are applied, and should serve as a useful reference for zoo researchers considering using GPS. In Chapter Three, I used GPS anklets to measure outdoor daily walking distance in 56 adult female African (n = 33) and Asian (n = 23) elephants housed in 30 zoos. I collected 259 days of data and found that elephants walked an average of 5.34 km/day with no significant difference between species. Multivariate regression models predicted that elephants with more dynamic feeding regimens (more diverse feeding types and frequencies; unscheduled feeding times) will walk more. Distance walked was also predicted to be higher in elephants that spend time in a greater number of different social groups. Distance walked was predicted to decline with age. Finally, I found a significant negative correlation between distance walked and nighttime space experience. The results of the analysis suggest that zoos that want to increase walking in their elephants need not rely solely on larger exhibits, but can increase walking by adding quality and complexity to exhibits. However, my results failed to establish a definitive link between walking distance and other validated measures of elephant welfare. Thus, the direct health and welfare benefits of walking in zoo elephants remain unresolved. Resting behaviors are an essential component of animal welfare, but have received little attention in zoological research. In Chapter Four, I used accelerometers in anklets to complete the first large-scale multi-species investigation of zoo elephant recumbence. I collected 344 days of data from 72 adult female African (n = 44) and Asian (n = 28) elephants at 40 zoos. I found that African elephants are recumbent an average of 2.14 hours/day, which is significantly less than Asian elephants at 3.22 hours/day. Multivariate regression models predicted that African elephant recumbence increases when they experience more space at night, and Asian elephant recumbence increases when they spend time housed alone. Both species showed a similar response to substrate, such that African elephants spending time on all-hard substrates are predicted to be recumbent less, while Asian elephants spending time on all-soft substrates are predicted to be recumbent more. The discovery that occasional non-recumbence is a common behavior in zoo elephants also introduces a new area of research that may have important animal welfare consequences. Finally, this study established that zoos should continue their efforts to replace hard substrate with soft substrate in order to provide zoo elephants with environments that facilitate recumbence. Overall, this work assessed walking and recumbence in zoo elephants, which will allow zoos to gauge the prevalence of these behaviors in their elephants as compared to the sub-population studied here. A variety of factors that are associated with these behaviors were also identified. With this information, zoos can prioritize modifications to their facilities and animal management programs to create an environment that encourages zoo elephants to express walking and recumbence behavior, should they choose to do so. This work is one component of the Elephant Welfare Project, the largest zoo animal welfare project ever undertaken, and is unprecedented in both scope and scale. The project was funded by the Institute of Museum and Library Services (IMLS), an independent, U.S., federal, grant-making agency that supports libraries, museums, and zoos. At the time of this writing, the first manuscripts from this project are being submitted to academic journals. These papers will describe the prevalence and distribution of a variety of elephant behaviors and welfare indicators, serve as a benchmark for future elephant welfare studies, and aid in decision making with regard to best practices in elephant management.

No description available.

South Africa’s growing elephant populations are concentrated in relatively small enclosed protected areas resulting in the over utilisation of the available food sources. Elephants and other herbivores as well as other natural disturbances such as fires and droughts play an important role in maintaining savannah environments. When these disturbances become too concentrated in a particular area the vegetation composition may be negatively affected. Excessive damage to the vegetation would result from exceeding the capacity of a protected area to provide food resources. The effect of the 120 elephants on the vegetation of Welgevonden Private Game Reserve, is not known. The rugged terrain of this reserve makes it a difficult, time consuming and labour intensive exercise to conduct ground studies. Satellite images can be used as a monitoring tool for vegetation change and improve the quantity and quality of environmental data to be collected significantly, allowing more informed management decision-making. This study evaluated the use of satellite imagery for monitoring elephant induced vegetation change on Welgevonden Private Game Reserve. The LANDSAT Thematic Mapper multispectral images, acquired at two yearly intervals from 1993 until 2007 were used. However, no suitable images were available for the years 1997, 2001 and 2003. A series of vegetation change maps was produced and the distribution of water sources and fire occurrences mapped. The areas of change were then correlated with the spatial distribution of water points and fire occurances, with uncorrelated areas of change. This was analysed using large animal population trends, weather data and management practices. On the visual comparison of the vegetation maps, it was seen that over this time period there was some decrease and thinning of woodland, but the most notable change was the increase of open woodland and decrease in grasslands. Using only the digital change detection for the period 1993 to 2007, a general increase in vegetation cover is seen. But this generalisation is misleading, since comparing the digital change detection to the vegetation maps indicates that while vegetation cover may have increased, significant changes occurred in the vegetation types. Most of the areas of significant change that were identified showed a strong positive correlation with burnt areas. The distribution of the water sources could not be directly linked to the vegetation change although rainfall fluctuations seemed to have accelerated vegetation changes. Years with high game counts, such as 1999, also coincide with very low rainfall making it difficult to differentiate between the effects of heavy utilisation of vegetation and low rainfall. Furthermore, many of the initial vegetation changes could be the result of land use changes due to the introduction of browsers, selective grazers and elephants that allow for more natural utilisation of the vegetation. Remote sensing makes it possible to successfully track changes in vegetation and identify areas of potential elephant induced vegetation change. Vegetation changes caused by disturbances, such as fire and anthropogenic activities, can be accounted for but it is not possible to conclude with a high level of certainty that the further changes seen are solely a result of elephant damage. Further work is required to reliably isolate elephant induced vegetation changes, as well as to establish the effects these changes have on the ecosystem as a whole. / Environmental Sciences / (M. Sc. (Environmetal Sciences))

South Africa’s growing elephant populations are concentrated in relatively small enclosed protected areas resulting in the over utilisation of the available food sources. Elephants and other herbivores as well as other natural disturbances such as fires and droughts play an important role in maintaining savannah environments. When these disturbances become too concentrated in a particular area the vegetation composition may be negatively affected. Excessive damage to the vegetation would result from exceeding the capacity of a protected area to provide food resources. The effect of the 120 elephants on the vegetation of Welgevonden Private Game Reserve, is not known. The rugged terrain of this reserve makes it a difficult, time consuming and labour intensive exercise to conduct ground studies. Satellite images can be used as a monitoring tool for vegetation change and improve the quantity and quality of environmental data to be collected significantly, allowing more informed management decision-making. This study evaluated the use of satellite imagery for monitoring elephant induced vegetation change on Welgevonden Private Game Reserve. The LANDSAT Thematic Mapper multispectral images, acquired at two yearly intervals from 1993 until 2007 were used. However, no suitable images were available for the years 1997, 2001 and 2003. A series of vegetation change maps was produced and the distribution of water sources and fire occurrences mapped. The areas of change were then correlated with the spatial distribution of water points and fire occurances, with uncorrelated areas of change. This was analysed using large animal population trends, weather data and management practices. On the visual comparison of the vegetation maps, it was seen that over this time period there was some decrease and thinning of woodland, but the most notable change was the increase of open woodland and decrease in grasslands. Using only the digital change detection for the period 1993 to 2007, a general increase in vegetation cover is seen. But this generalisation is misleading, since comparing the digital change detection to the vegetation maps indicates that while vegetation cover may have increased, significant changes occurred in the vegetation types. Most of the areas of significant change that were identified showed a strong positive correlation with burnt areas. The distribution of the water sources could not be directly linked to the vegetation change although rainfall fluctuations seemed to have accelerated vegetation changes. Years with high game counts, such as 1999, also coincide with very low rainfall making it difficult to differentiate between the effects of heavy utilisation of vegetation and low rainfall. Furthermore, many of the initial vegetation changes could be the result of land use changes due to the introduction of browsers, selective grazers and elephants that allow for more natural utilisation of the vegetation. Remote sensing makes it possible to successfully track changes in vegetation and identify areas of potential elephant induced vegetation change. Vegetation changes caused by disturbances, such as fire and anthropogenic activities, can be accounted for but it is not possible to conclude with a high level of certainty that the further changes seen are solely a result of elephant damage. Further work is required to reliably isolate elephant induced vegetation changes, as well as to establish the effects these changes have on the ecosystem as a whole. / Environmental Sciences / (M. Sc. (Environmetal Sciences))

Balancing increasing elephant numbers with biodiversity conservation in small reserves has become a concern for many protected area managers. Elephants are considered important agents of disturbance creating heterogeneity and thus contributing to the maintenance of biodiversity. However elephants also damage vegetation through their destructive feeding habits, and this has led to pressure to reduce elephant populations in many reserves. Quantitative data on the impact of elephants on invertebrates, the main component of biodiversity at the species level, are lacking. The aim of this project was to assess the effect that habitat alteration by elephants has on the diversity of selected ground-dwelling invertebrates (ants, centipedes, millipedes, spiders, scorpions and termites) through the provision of logs and dung as a potential refuge niche for these invertebrate communities, and to determine the effect of spatial (vegetation types) and temporal (season and age of dung) variation on the invertebrates using these refugia. Variation in impacts was considered important because savanna is not homogenous and the impact of the refugia is likely to be dynamic in terms of seasonal trends in invertebrate populations, and in terms of changes in the environmental conditions offered by the refugia. Elephant impact on vegetation, quantity of refugia (logs and dung) produced and invertebrate diversity associated with refugia were determined for 115 transects within Madikwe Game Reserve in the North Western Province, South Africa. Invertebrate abundance, species richness and diversity were always higher under refugia than in areas without refugia. Vegetation utilisation, frequency of refugia production and invertebrate diversity showed strong temporal variation (seasonal); elephant impact and production of logs were higher in winter than in summer because elephants are more likely to feed on woody vegetation in winter when grass nutrient levels are low. Invertebrate diversity under the logs was higher in summer than in winter, and this probably reflected the higher abundance and diversity of invertebrates that are usually associated with the warmer, wetter summer months. The effect of adding refugia to three vegetation types on invertebrate diversity was tested experimentally at Makalali Private Game Reserve in the Limpopo Province, South Africa. Logs and elephant dung were set out in five plots each measuring 20m x 20m within Govender - iii mixed bushveld, riverine and mopane woodland. Significant differences were observed in invertebrate abundance, species richness and diversity between the refugia and control plots that lacked refugia and between the three vegetation types sampled. Similarity between invertebrate communities utilising the different refugia types and between the three different vegetation types were tested using the Jaccard similarity coefficient. The three vegetation types shared fewer than 50% of their species, as did the logs, dung and control sites. However the results obtained do illustrate a higher degree of similarity between the refugia substrates (logs and dung) than the control sites and between the more heterogeneous vegetation types (mixed bushveld and riverine) than the mopane veld. This indicated that invertebrate communities associated with refugia were not uniform, but were influenced by vegetation type. An experimental test of temporal changes in invertebrate community composition illustrated the importance of elephant dung as a microhabitat for different invertebrate groups over different ages of dung (three days, two, four, 12 and 32 weeks old). Colonisation of the dung, by dung beetles was immediate but as the microclimate of the dung changed with time, the new conditions were ideal for other invertebrate taxa. Over a period of eight months, the change of invertebrate communities utilising the dung included dung beetles, followed by millipedes and [mally ant and termite communities. The results of this study illustrated the importance of refugia (logs and dung) produced by elephants for ground-dwelling invertebrate species in the savanna environment. The extent of the influence of the refugia varied both spatially and temporally and this should be considered in future monitoring or in measuring impacts. While further research on a broader range of organisms and at larger scales is necessary, elephants do have a positive impact on at least some components of biodiversity, through the process of facilitation of refugia. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Elephants (Loxodonta africana, Blumenbach) are recognised as keystone herbivores and ecosystem engineers in African ecosystems due to the noticeable impact they have on plant communities. This impact can influence other animal taxa and ecosystem processes, especially within enclosed systems. I investigated the effects of elephants in four vegetation types and the cascade effect on three associated taxa and two ecosystem processes at five sites with elephants and five paired sites without elephants in the Eastern Cape Province, South Africa, between April 2005 and July 2007. In grassland habitats, the physical structure of the vegetation was neither enhanced nor degraded in the presence of elephants. Within the locally important Thicket Biome, elephant browsing transformed relatively homogeneous stands of vegetation into more heterogeneous units. However, although seeds from thicket plant species were recorded in elephant dung, elephants did not promote the viability and germination success of these plants. In addition, elephant foraging on aloes caused declines in their populations. By contrast, the size of bushclumps was not reduced in the presence of elephants in bushclump savanna. The associated insect, bird and mammal communities appeared to benefit from elephant foraging in all vegetation types assessed, whereas vegetation patch dynamics and soil surface processes were neither enhanced nor degraded in the presence of elephants. I conclude that, at current densities, elephants do not (in most cases) negatively affect plant and animal communities or ecosystem processes in enclosed reserves. However, elephants have only been present at each site for a relatively short period and it is likely that their impact will be cumulative, increasing over time in these closed systems. Thus, future research along a continuum of elephant density and time since re-introduction is recommended.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-01-16T10:46:45Z No. of bitstreams: 2 Tese - Daniel Augusta Zacarias - 2017 (1).pdf: 10564997 bytes, checksum: 3beb8a6a9c5b45ffef1c47b91fb5ee3c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-01-16T10:47:18Z (GMT) No. of bitstreams: 2 Tese - Daniel Augusta Zacarias - 2017 (1).pdf: 10564997 bytes, checksum: 3beb8a6a9c5b45ffef1c47b91fb5ee3c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-01-16T10:47:18Z (GMT). No. of bitstreams: 2 Tese - Daniel Augusta Zacarias - 2017 (1).pdf: 10564997 bytes, checksum: 3beb8a6a9c5b45ffef1c47b91fb5ee3c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-12-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Biodiversity conservation is in crisis and urgent responses are needed to reverse the extinction of species, the proliferation of invasive species and the fragmentation of habitats. Among several approaches being implemented, the protection of species with great dispersal capacity and that play important ecological role has been advocated as a solution, since the protection of their habitat in parallel contributes to the protection of other species and habitats. The elephant, a megagardener of forests and savannahs, represents this type of species in the sense that it inhabits vast areas, has a high dispersal capacity and guarantees the dispersion and growth of plant species in extensive areas. Unfortunately, the current situation of the elephant is not positive and international efforts have been developed to reverse the current scenarios of reduction of its abundance and the protection of its habitat. This thesis focuses on African elephant species (Loxodonta africana and Loxodonta cyclotis) and aims to contribute to the knowledge of the main challenges that must be embraced for their protection, using an interdisciplinary approach involving scientometric analysis, climate niche modelling, multi-scale modelling of habitat connectivity, quasi-linear regression models and structural equations and knowledge syntheses. Chapter I presents a systematic review of conservation genetics studies of the African savannah elephant and discusses the main research areas, the elephant populations involved and the main lines of research addressed. Chapter 2 presents the modelling of the climatic niche response to multi-temporal climate change and determines the potential for connectivity between remaining elephant habitats and chapter 3 presents the interaction between environmental, socioeconomic and governance indicators to explain abundance of elephants in Africa, based on the most recent IUCN estimates. The fourth chapter discusses the main challenges associated with the introduction of African elephants as a strategy for the recovery of lost ecological functions with the extinction of megafauna in the Pleistocene, and the fifth chapter, which concludes, presents the synthesis of challenges and opportunities for the conservation of African elephants. / A conservação da biodiversade está em crise e são necessárias respostas urgentes para reverter a extinção de espécies, a proliferação de espécies invasoras e a fragmentação de habitats. Dentre as várias abordagens sendo implementadas, a proteção de espécies com grande capacidade de dispersão e que desempenham papel ecológico importante tem sido advogada como solução, na medida em que a proteção de seu habitat paralelamente contribui para a proteção de outras espécies e habitats. O elefante, megajardineiro das florestas e savanas, representa este tipo de espécies, no sentido em que habita vastas áreas, tem elevada capacidade de dispersão e garante a dispersão e crescimento de espécies vegetais por vastas áreas. Infelizmente a situação actual do elefante não é positiva e esforços internacionais têm sido desenvolvidos no sentido de reverter os atuais cenários de redução de sua abundancia e a proteção do seu habitat. Esta tese debruça-se sobre as espécies de elefante africano (Loxodonta africana e Loxodonta cyclotis) e procura contribuir para o conhecimento dos principais desafios que devem ser abraçados para a sua proteção, servindo-se de uma abordagem interdisciplinar envolvendo análise cienciométrica, modelagem de nicho climático, modelagem multi-escala de conectividade de habitats, modelos de regressão quasi-linear e de equações estruturais e sínteses de conhecimento. O capítulo 1 apresenta faz a revisão sistemática dos estudos de genética de conservação do elefante africano de savana e discute os principais eixos de pesquisa, as populações de elefantes envolvidas e as principais linhas de pesquisa abordadas. O capítulo 2 apresenta a modelagem da resposta do nicho climático em função de alterações climáticas multi-temporais e determina o potencial de conectividade entre os habitats remanescentes de elefantes e o capítulo 3 apresenta a interação entre indicadores ambientais, socioeconômicos e de governança para explicar a abundância de elefantes em África, tomando como base nas mais recentes estimativas da IUCN. O quarto capítulo discute os principais desafios associados à introdução de elefantes africanos como estratégia para a recuperação de funções ecológicas perdidas com a extinção da megafauna no Pleistoceno e o quinto capítulo, que faz de conclusão, apresenta a síntese dos desafios e oportunidades para a conservação dos elefantes africanos.