Demographic, biological and behavioural knowledge, together with information on the ecological interactions and impact of a species is fundamental to effective management of most mammal species. In this study, these aspects were investigated for a population of feral horses in the Namib Naukluft Park of Namibia, which lies within a part of the Namib Desert. An attempt was made to evaluate the justification of the continued existence of this exotic species in a conservation area, as well as to provide baseline information and recommendations regarding management of these horses. The study investigated the botanical component and grazing capacity of the area inhabited by the horses, as well as the demography and quality of life of the horses. The study further examined the possible negative impact the horses may have on the natural biodiversity of the area. Finally, it looked at the historic, scientific, aesthetic and economic values of the horses. The collected data was then used as a technical basis for the development of a draft management plan during a stakeholder workshop. The study proposed a range of grazing capacity values related to the total rainfall of the preceding twelve months, based on grass production in response to rainfall in different plant communities. The horses, as well as the native large herbivores, utilized the study area according to the patchy rainfall patterns typically found in the Namib Desert. The population size of the horses fluctuated between 89 and 149 over a ten year period. The social structure of the population was more significantly influenced by artificial interference than natural disasters which had implications on natality, mortality and genetic viability. Termite activity, measured as utilization of grass provided in bait boxes, did not correlate with horse density and seems, instead, to be influenced by soil properties. The results of ant and tenebrionid beetle species composition surveys and analyses did not indicate a significant negative impact from the horses on the study area. No indication could be found that the horses threaten the survival of any native species in the area or that they change the vegetation structure. It appears as if the biodiversity of the area is subjected to large natural stresses due to the continued and frequent desiccation in the desert environment. The impact of the horses is therefore probably minor to that of the climatic stochasticity. It also became apparent that the horses have developed significant historical, scientific and tourism value. The general public opinion is that the horses should be managed as a wild population with minimal artificial interference. / Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2006.

Demographic, biological and behavioural knowledge, together with information on the ecological interactions and impact of a species is fundamental to effective management of most mammal species. In this study, these aspects were investigated for a population of feral horses in the Namib Naukluft Park of Namibia, which lies within a part of the Namib Desert. An attempt was made to evaluate the justification of the continued existence of this exotic species in a conservation area, as well as to provide baseline information and recommendations regarding management of these horses. The study investigated the botanical component and grazing capacity of the area inhabited by the horses, as well as the demography and quality of life of the horses. The study further examined the possible negative impact the horses may have on the natural biodiversity of the area. Finally, it looked at the historic, scientific, aesthetic and economic values of the horses. The collected data was then used as a technical basis for the development of a draft management plan during a stakeholder workshop. The study proposed a range of grazing capacity values related to the total rainfall of the preceding twelve months, based on grass production in response to rainfall in different plant communities. The horses, as well as the native large herbivores, utilized the study area according to the patchy rainfall patterns typically found in the Namib Desert. The population size of the horses fluctuated between 89 and 149 over a ten year period. The social structure of the population was more significantly influenced by artificial interference than natural disasters which had implications on natality, mortality and genetic viability. Termite activity, measured as utilization of grass provided in bait boxes, did not correlate with horse density and seems, instead, to be influenced by soil properties. The results of ant and tenebrionid beetle species composition surveys and analyses did not indicate a significant negative impact from the horses on the study area. No indication could be found that the horses threaten the survival of any native species in the area or that they change the vegetation structure. It appears as if the biodiversity of the area is subjected to large natural stresses due to the continued and frequent desiccation in the desert environment. The impact of the horses is therefore probably minor to that of the climatic stochasticity. It also became apparent that the horses have developed significant historical, scientific and tourism value. The general public opinion is that the horses should be managed as a wild population with minimal artificial interference. / Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2006.

Environmental impacts of feral horses (Equus caballus) are a subject of conservation concern and controversial national policy. In North America, feral horses are considered an invasive species where they impact rangelands of the arid and semi-arid western United States. The greater sage-grouse (Centrocercus urophasianus) is a native sagebrush obligate bird species that relies on sagebrush habitats to sustain viable population levels. Recent literature suggests that feral horse presence can have a notable effect on the fitness of native and sagebrush obligate species throughout the arid and semi-arid western United States. The purpose of this thesis was to assess the potential impact of feral horses on population patterns and on late-brood rearing habitat of greater sage-grouse throughout the Great Basin. This was accomplished by pairing known sage-grouse use sites (leks and late brood-rearing habitat) to random sites for comparison. Within each pair, one site was located within Herd Management Area (HMA) boundaries (with assumed horse presence) while the other was located outside (with assumed horse absence). We then assessed lek attendance throughout the state of Nevada and compared attendance rates to known horse population estimates. Furthermore, paired late brood-rearing habitat sites were compared to one another to assess the effect of horse and cattle presence on habitat quality and characteristics. We determined that mean sage-grouse population size at leks is higher (9.14 ± 1.04 males) within HMA boundaries compared to areas outside of HMA boundaries (6.55 ± 0.74 males). Considering late brood-rearing habitat, we determined that statistical differences have occurred between horse and non-horse use sites in the following comparisons: annual grass frequency, percent annual grass cover, dung frequency, total plant height, vegetative height, and horse and cattle dung density. We suggest that feral horse presence can impact sage-grouse habitat, however, a more clear understanding of horse effects on rangeland wildlife habitat is needed to assess actual impacts on wildlife populations in consideration of multiple use management decisions.

Feral horse management has become a subject of significant controversy in the United States. This is because of differing opinions and minimal recent empirical data on feral horses. In recent years, numbers of feral horses have increased due to governmental horse removal restrictions (specifically the Wild Horse and Burro act of 1971). With increasing numbers of feral horses on rangelands, land managers are challenged with identifying the appropriate course of action for satisfying groups with differing opinions. The purpose of this study is to characterize diet consumption through the use of stable isotope dietary analysis (δ15N and δ13C). We did this in order to measure the impact of feral horse forage consumption on rangelands and to propose strategies for improving habitat management and conservation. We obtained tail hair isotopic values from tail hair removed while horses that were held in squeeze chutes following a roundup. Resulting isotopic values were compared to plant isotopic values using plant samples obtained from the geographical areas as the horses in order to characterize diet. Contribution of the various plant species to the tail hair mixture values was determined using the EPA program IsoSource©. Initial analysis of tail hair isotopes demonstrated seasonal variation. During summer months, shrubs (mostly Artemesia spp, and Purshia Tridentate), Elymus elymoides, Juncus balticus, and Festuca idahoensis were the predominantly consumed vegetative species. During fall months, Leymus cinereus and Juncus balticus played a more significant role in feral horse diet. In the winter, shrubs were more heavily consumed along with Poa secunda. Springtime showed a shift towards forb consumption. Changes in seasonal consumption of forages are most likely linked to forage availability as well as equine preference. We analyzed plant metrics (specifically biomass, abundance, and cover) to compare a site with horses present to a site where horses had been removed the previous year and found relatively few differences between the two sites. With nearly all differences we found higher plant production (forage availability) on the site where horses were still present. In riparian areas however, there was more vegetation (specifically Carex rossii, Juncus balticus, and Poa secunda) on the site where horses had been removed. Within riparian areas, only Bromus tectorum (a plant not typically found in riparian areas but characteristic of degraded areas) showed significantly greater amounts of biomass on the site with horses present. Knowledge of plant species consumption will allow land managers greater ability to make scientifically based decisions regarding feral horse population control which is important in determining appropriate management levels of populations.

Feral horses occupy 31.6 million acres throughout western North America. Feral horses share similar habitats with a wide range of animal species, including pronghorn. Since horses are larger and often more aggressive than other animals of this region, they are generally socially dominant over all other native ungulate species. Pronghorn share water sources with horses in areas where both occur. In situations where horses exclude pronghorn from water, pronghorn fitness may be impaired, especially during the hottest months of the year when water is limited. The purpose of this study was to investigate interference competition between pronghorn and feral horses at water sources. During spring and summer 2010-11, we placed motion-sensitive cameras at water sources across the Sheldon National Wildlife Refuge in northwest Nevada. Cameras were used to examine the overlap of water use by pronghorn and horses and to determine the occurrence of spatial or temporal partitioning of water between these species. Additionally, we made direct observations of horses and pronghorn at high-use water sources to record the occurrences and outcomes of pronghorn/horse interactions as well as differences in pronghorn behavior in the presence and absence of horses. Pronghorn spent more time on vigilance behavior and less time foraging or drinking in the presence of horses than in their absence. Nearly half of pronghorn/horse interactions at water resulted in pronghorn exclusion from water. Our data also suggest that temporal partitioning of water between horses and pronghorn on an hourly basis may be occurring.

No description available.

Vom Frühjahr 2010 bis Frühsommer 2011 wurden Verhalten, intra- und interspezifische Interaktionen sowie Raumnutzung von Wisenten (Bison bonasus), Exmoor-Ponys (Equus ferus) und Dybowski-Hirschen (Cervus nippon hortulorum) auf einer 14 ha großen Gemeinschaftsanlage im Tierpark Sababurg untersucht. 15 Individuen wurden dazu insgesamt für 605 Stunden mittels focal-animal und scan sampling beobachtet. Die Mittelwerte der Hauptverhaltensweisen über den gesamten Beobachtungszeitraum ergaben bei den Wisenten Tagesanteile von 47,73 % für Nahrungsaufnahme, 43,05 % für Ruheverhalten, 6,79 % für Fortbewegung und 1,68 % für Komfortverhalten. Die Exmoor-Ponys fraßen 58,62 % des Tages, ruhten 34,54 %, nutzten 3,87 % für die Fortbewegung und verbrachten 1,37 % mit Komfortverhalten. 47,22 % der Zeit wurden von den Dybowski-Hirschen zur Nahrungsaufnahme verwendet, 43,64 % geruht, 4,55 % zur Fortbewegung genutzt und 2,44 % mit Komfortverhalten verbracht. All diese Verhaltensweisen waren Bestandteil eines artspezifischen Tagesrhythmus aus alternierenden Nahrungsaufnahme- und Ruhephasen. Die prozentualen Anteile und somit auch die Ausprägung dieses Tagesrhythmus variierten dabei allerdings teilweise stark zwischen den einzelnen Jahreszeiten und den damit verbundenen klimatischen und umweltbedingten Veränderungen. Die Individuen aller drei Arten verhielten sich dabei völlig normal im Rahmen der nachgewiesenen Bandbreite des natürlichen Verhaltens ihrer wildlebenden Artgenossen, unbeeinflusst von den Gehegebedingungen und Eingriffen des Zuchtmanagements. Interspezifische Interaktionen traten regelmäßig auf, positive Kontakte blieben dabei allerdings auf die Exmoor-Ponys und die Dybowski-Hirsche beschränkt. Agonistische Interaktionen waren meist lediglich als einfache Drohgebärden oder als indirekte Interaktionen ohne körperlichen Kontakt feststellbar. Eine feste Artenhierarchie ist etabliert und wird von allen Tieren akzeptiert, wobei die Wisente die dominante Rolle einnehmen, gefolgt von den Exmoor-Ponys und den Dybowski-Hirschen. Die Habitatnutzungsanalyse ergab für alle drei Arten bevorzugte Aufenthaltsbereiche und genutzte Gehegeobjekte. Dabei war wie das Verhalten auch die Habitatnutzung stark von den jahreszeitlich veränderlichen Umweltbedingungen beeinflusst. Während die offeneren Areale insbesondere im Frühjahr und Herbst genutzt wurden, bevorzugten die Tiere im Sommer und Winter eher die geschützteren Anlagenbereiche, im Sommer hauptsächlich als Schattenbereich, im Winter als Wetterschutz. Zusammenfassend betrachtet funktioniert das Zusammenleben der Wisente, Exmoor-Ponys und Dybowski-Hirsche im Tierpark Sababurg ohne Probleme und kann als Beispiel-Projekt für die zukünftige Forschung über die Möglichkeiten für Beweidungsprojekte mit heimischen Wildtieren im Naturschutz dienen.