Made available in DSpace on 2014-06-12T15:04:04Z (GMT). No. of bitstreams: 2 arquivo1234_1.pdf: 2155674 bytes, checksum: 396ef799d17aa406c7a896cee2d93811 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009 / Este trabalho analisou a variação na composição da dieta de Tyto alba (Scopoli, 1769) (Strigiformes, Tytonidae) a partir de presas identificadas em pelotas de regurgitação entre duas áreas ecologicamente distintas. As coletas foram realizadas no período de julho de 2006 a julho de 2008, em uma área rural e uma urbana em Pernambuco, nordeste do Brasil. Ao todo, foram coletadas e analisadas 647 pelotas completas, além de fragmentos, com 833 itens compreendendo 16 espécies. Os pequenos mamíferos foram as principais presas na dieta de Tyto Alba representando 93,3% do número total e foram seguidos de invertebrados (3,2%), répteis (3,1%) e aves (1,3%). A composição da dieta diferiu entre as duas áreas. A biomassa média das presas consumidas por Tyto alba foi significativamente maior em Olinda (135,3g ±15,84g) do que na EET (46,5g ± 14,17g) (U= 18; p= 0) e a riqueza foi significativamente maior na área rural em relação à urbana (U=35; p < 0,02) mas não houve diferença no número de presas consumidas pela suindara entre as duas áreas. Não houve variação sazonal no consumo de presas para as duas localidades. Não houve diferença no número de presas consumidas entre as duas áreas. Não houve variação sazonal no consumo de presas para as duas localidades. A variação na composição da dieta é explicada pelo comportamento generalista da suindara, que substitui as presas de acordo com a disponibilidade no ambiente. A ausência de sazonalidade neste estudo está relacionada a uma provável abundância de recursos às espécies mais predadas, o que permite uma reprodução contínua e consequentemente uma maior abundância destas espécies durante todo o período de estudo. Entre as espécies encontradas nas pelotas destacam-se os marsupiais didelfídeos Gracilinanus agilis e Cryptonanus agricolai, que constituem os primeiros registros destes táxons na Floresta Atlântica de Pernambuco e na ântica de Pernambuco e na região costeira nordestina respectivamente. Os resultados encontrados neste estudo confirmam a importância do estudo de pelotas de regurgito como fonte de informação sobre a diversidade da fauna de pequenos mamíferos, e o papel das suindaras como potenciais agentes bióticos no controle populacional de roedores em ambientes modificados como plantações e cidades

With the increase in the number of fast-moving vehicles and the simultaneous development of road building technology, roadside bird mortality has become an increasingly important environmental issue that has the potential to do serious damage to already vulnerable bird populations. This project was therefore initiated after an alarming number of owls were found dead along the N17 and R550 roads in the rural areas between Springs and Devon in the East Rand highveld of Gauteng Province. Five hundred and fifty four owls of four species, namely Marsh Owls, the Red Data listed Grass Owl, Barn Owl and the Spotted Eagle Owl were collected on the stretches of the R550 and N17 during the period between October 2001 and September 2003. They accounted for 53.6%, 27.4%, 17.5% and 1.3% of the mortalities respectively. Unidentified species of owls accounted for the remaining 0.2%. It was found that the monthly mortality rates of the birds varied throughout the year, with the greatest losses being suffered during July, as opposed to relatively lower mortalities occurring during the warmer months. All carcasses were collected, their GPS locations plotted on a map, and ‘hotspot areas’ identified as places of highest incidences of mortalities of the owls. Vehicle-induced mortalities are then discussed in relation to these hotspots, in terms of vegetation and habitat descriptions, daily vehicle counts along the route, as well as fixtures found along the route. It was found that traffic density was indirectly proportional to owl mortalities, with higher traffic speeds definitely having an increasingly detrimental effect on the owl mortalities. Weather conditions also play a role in mortality counts, with the mortalities being significantly negatively correlated to rainfall. Moon phases were also related to the times of highest mortalities, however, this factor did not play a significant role in influencing road mortalities. Another factor that was studied was the influence of differing tarmac road surface temperatures as opposed to gravel road verge surface temperatures, and how these temperatures differed from the ambient temperature. It was found that there was not a big enough difference in the temperatures that would warrant (the previously thought notion) that the owls were attracted to the roads at night to gain heat. Gravel roads had very low incidences of owl mortalities with the highest mortalities recorded along tarmac roads that are bordered by open grasslands or cattle grazing paddocks. It was shown that tarmac roads, bordered by croplands, had a lesser effect on the owl mortalities. Another factor influencing the road mortalities of the owls is grain that is spilled on the road during transport. This initially seemed to be the major factor in attracting granivorous rodents to the roads, and in turn, attracting the owls to prey on them. Rodents identified from recovered pellets and the stomach contents of dead owls confirmed the fact that the majority of rodent prey items were indeed granivorous species, namely Mastomys natalensis and Rhabdomys pumilio. This is in disagreement with previous studies that indicated that a large proportion of the prey species of the Grass Owl was Otomys irroratus, a grass-eating species, even though a rodent trapping study to determine prey abundance within the area indicated a healthy population of O. irroratus. Further studies into prey items of the owls that were dissected indicated that the majority of the prey items recovered were not caught directly on the road as it was already partially digested, suggesting that the prey was caught prior to the owl being killed. From the pellet analyses, other prey items were also found to form part of the owls’ diets. It was found that insects formed largely the diet of the Marsh Owl during the spring, summer and autumn months, with them resorting to smaller rodents during the winter months. Spotted Eagle Owls also preyed almost exclusively on insects. Grass Owls, on the other hand, preyed on small mammals exclusively, with the very rare exception of some insects also being taken. Of all of the dead owls recovered on the roads, post mortems were carried out on only 78 of the carcasses. All of the dead owls examined were in good health prior to death. Various morphometrics of the examined owls were noted. Comparisons of body mass showed that females were larger than males for most species. This was also found for most other measurements as well. It was also found that, according to body mass comparisons, Barn Owls and Marsh Owls were significantly similar. Conducting ANOVA analysis on other morphometrics to determine gender differences, it was found that Grass Owl males were significantly different to females in terms of body mass and length. Marsh Owl males were significantly different to females in terms of body mass and tail length; with Barn Owl males being significantly different in terms of tarsus length to females. Except for Spotted Eagle Owl tarsus lengths all other measurements were in favour of females being significantly larger. These findings were also confirmed when applying the Dimorphism Index to all morphometrics measurements, especially body mass. The degree of parasite infestation was also studied during post mortem examinations. Very few cestodes and nematodes were found, with too few to have an effect on the overall health of the birds prior to death. The vegetation type was studied at transects that coincided with hotspot and non-hotspot sites. Using the PRIMER statistical software package, hotspot sites were found to have highest plant cover and diversity, whereas nonhotspot sites showed lowest plant cover and diversity, generally dominated by Hyparrhenia hirta. During these studies, the degree of available nesting habitat was determined and nesting sites were identified, using the ropedragging technique to flush out roosting and nesting owls that would otherwise have been impossible to find in the thick cover. It was found that Grass Owls preferred a habitat rich in thick grass cover that was relatively high (0.75 m–1 m). It was found that the grass species preferred by these owls were Eragrostis curvula, Paspalum sp., Setaria sp., Sporobolis sp., with few other small herbaceous plants. Marsh Owls, on the other hand, seemed not to be too partial regarding roosting and nesting sites, with them roosting and breeding in more mixed vegetation grasslands that had sparser cover, not reaching the height of the grass cover typical of the habitat preferred by the Grass Owls. Opposed to this were the non-hotspot vegetation sites. These sites were found to have vegetation cover unsuited to both the Marsh and Grass owls, with mixed H. hirta grassland not forming the dense cover, or the height, needed by those two species of owls. Foraging owls were also observed, with the vegetation type in the immediate vicinity noted. Vegetation types similar to breeding areas were noted in these foraging areas. Habitat preferences as well as breeding performance were noted for both grassland species of owls, and found to be directly related to land usage in terms of varying agricultural practices and regimes. Fallow, undisturbed lands were found to be highly productive for the owls. Lands planted with Eragrostis sp. were also found to be very productive, but only if left undisturbed for a period of time sufficient to allow the grassland owls to colonise it. Maize-planted fields were found to be utilised only as foraging fields and no breeding of owls was found to take place close to these fields. After extensive nest searching, it was found that both Marsh and Grass owls were breeding from late March to early June, with the Barn Owls breeding in October and again in March. Grass Owls occur in the study area because of the presence of a natural corridor of suitable habitat that runs parallel with the Blesbokspruit. This favourable habitat of the study area is thus conducive to high population density of grassland owls utilising these uncultivated patches of dense and tall vegetation. The high incidence of mortalities on the road in the study area is due to the concomitant high population densities. This healthy population seems to be sustaining the losses occurring on roads. Owls also seem to be gathering in larger numbers in hotspot zones because of the easy available prey, which are attracted to these high productive areas. Agricultural practices in the area lead to the spillage of grain on the road during transportation. Potential prey species foraging on the roads expose themselves to the nocturnal hunters offering an easy dinner. This process leaves these owls vulnerable to vehicle collisions. The overall population size may be larger than previously thought, not with standing the high mortalities already recorded. The small patches of viable habitat in the study area remains suitable for the breeding of the two grassland owl species allowing for such high densities to occur in the area. The Grass Owl, nonetheless, remains severely threatened as it already occurs as a high priority species for conservation concern in the Gauteng Province. This study provides the first assessment of this owl species of this scale in South Africa and this will ultimately promote the long-term survival of these owls. / Dr. V. Wepener

With the increase in the number of fast-moving vehicles and the simultaneous development of road building technology, roadside bird mortality has become an increasingly important environmental issue that has the potential to do serious damage to already vulnerable bird populations. This project was therefore initiated after an alarming number of owls were found dead along the N17 and R550 roads in the rural areas between Springs and Devon in the East Rand highveld of Gauteng Province. Five hundred and fifty four owls of four species, namely Marsh Owls, the Red Data listed Grass Owl, Barn Owl and the Spotted Eagle Owl were collected on the stretches of the R550 and N17 during the period between October 2001 and September 2003. They accounted for 53.6%, 27.4%, 17.5% and 1.3% of the mortalities respectively. Unidentified species of owls accounted for the remaining 0.2%. It was found that the monthly mortality rates of the birds varied throughout the year, with the greatest losses being suffered during July, as opposed to relatively lower mortalities occurring during the warmer months. All carcasses were collected, their GPS locations plotted on a map, and ‘hotspot areas’ identified as places of highest incidences of mortalities of the owls. Vehicle-induced mortalities are then discussed in relation to these hotspots, in terms of vegetation and habitat descriptions, daily vehicle counts along the route, as well as fixtures found along the route. It was found that traffic density was indirectly proportional to owl mortalities, with higher traffic speeds definitely having an increasingly detrimental effect on the owl mortalities. Weather conditions also play a role in mortality counts, with the mortalities being significantly negatively correlated to rainfall. Moon phases were also related to the times of highest mortalities, however, this factor did not play a significant role in influencing road mortalities. Another factor that was studied was the influence of differing tarmac road surface temperatures as opposed to gravel road verge surface temperatures, and how these temperatures differed from the ambient temperature. It was found that there was not a big enough difference in the temperatures that would warrant (the previously thought notion) that the owls were attracted to the roads at night to gain heat. Gravel roads had very low incidences of owl mortalities with the highest mortalities recorded along tarmac roads that are bordered by open grasslands or cattle grazing paddocks. It was shown that tarmac roads, bordered by croplands, had a lesser effect on the owl mortalities. Another factor influencing the road mortalities of the owls is grain that is spilled on the road during transport. This initially seemed to be the major factor in attracting granivorous rodents to the roads, and in turn, attracting the owls to prey on them. Rodents identified from recovered pellets and the stomach contents of dead owls confirmed the fact that the majority of rodent prey items were indeed granivorous species, namely Mastomys natalensis and Rhabdomys pumilio. This is in disagreement with previous studies that indicated that a large proportion of the prey species of the Grass Owl was Otomys irroratus, a grass-eating species, even though a rodent trapping study to determine prey abundance within the area indicated a healthy population of O. irroratus. Further studies into prey items of the owls that were dissected indicated that the majority of the prey items recovered were not caught directly on the road as it was already partially digested, suggesting that the prey was caught prior to the owl being killed. From the pellet analyses, other prey items were also found to form part of the owls’ diets. It was found that insects formed largely the diet of the Marsh Owl during the spring, summer and autumn months, with them resorting to smaller rodents during the winter months. Spotted Eagle Owls also preyed almost exclusively on insects. Grass Owls, on the other hand, preyed on small mammals exclusively, with the very rare exception of some insects also being taken. Of all of the dead owls recovered on the roads, post mortems were carried out on only 78 of the carcasses. All of the dead owls examined were in good health prior to death. Various morphometrics of the examined owls were noted. Comparisons of body mass showed that females were larger than males for most species. This was also found for most other measurements as well. It was also found that, according to body mass comparisons, Barn Owls and Marsh Owls were significantly similar. Conducting ANOVA analysis on other morphometrics to determine gender differences, it was found that Grass Owl males were significantly different to females in terms of body mass and length. Marsh Owl males were significantly different to females in terms of body mass and tail length; with Barn Owl males being significantly different in terms of tarsus length to females. Except for Spotted Eagle Owl tarsus lengths all other measurements were in favour of females being significantly larger. These findings were also confirmed when applying the Dimorphism Index to all morphometrics measurements, especially body mass. The degree of parasite infestation was also studied during post mortem examinations. Very few cestodes and nematodes were found, with too few to have an effect on the overall health of the birds prior to death. The vegetation type was studied at transects that coincided with hotspot and non-hotspot sites. Using the PRIMER statistical software package, hotspot sites were found to have highest plant cover and diversity, whereas nonhotspot sites showed lowest plant cover and diversity, generally dominated by Hyparrhenia hirta. During these studies, the degree of available nesting habitat was determined and nesting sites were identified, using the ropedragging technique to flush out roosting and nesting owls that would otherwise have been impossible to find in the thick cover. It was found that Grass Owls preferred a habitat rich in thick grass cover that was relatively high (0.75 m–1 m). It was found that the grass species preferred by these owls were Eragrostis curvula, Paspalum sp., Setaria sp., Sporobolis sp., with few other small herbaceous plants. Marsh Owls, on the other hand, seemed not to be too partial regarding roosting and nesting sites, with them roosting and breeding in more mixed vegetation grasslands that had sparser cover, not reaching the height of the grass cover typical of the habitat preferred by the Grass Owls. Opposed to this were the non-hotspot vegetation sites. These sites were found to have vegetation cover unsuited to both the Marsh and Grass owls, with mixed H. hirta grassland not forming the dense cover, or the height, needed by those two species of owls. Foraging owls were also observed, with the vegetation type in the immediate vicinity noted. Vegetation types similar to breeding areas were noted in these foraging areas. Habitat preferences as well as breeding performance were noted for both grassland species of owls, and found to be directly related to land usage in terms of varying agricultural practices and regimes. Fallow, undisturbed lands were found to be highly productive for the owls. Lands planted with Eragrostis sp. were also found to be very productive, but only if left undisturbed for a period of time sufficient to allow the grassland owls to colonise it. Maize-planted fields were found to be utilised only as foraging fields and no breeding of owls was found to take place close to these fields. After extensive nest searching, it was found that both Marsh and Grass owls were breeding from late March to early June, with the Barn Owls breeding in October and again in March. Grass Owls occur in the study area because of the presence of a natural corridor of suitable habitat that runs parallel with the Blesbokspruit. This favourable habitat of the study area is thus conducive to high population density of grassland owls utilising these uncultivated patches of dense and tall vegetation. The high incidence of mortalities on the road in the study area is due to the concomitant high population densities. This healthy population seems to be sustaining the losses occurring on roads. Owls also seem to be gathering in larger numbers in hotspot zones because of the easy available prey, which are attracted to these high productive areas. Agricultural practices in the area lead to the spillage of grain on the road during transportation. Potential prey species foraging on the roads expose themselves to the nocturnal hunters offering an easy dinner. This process leaves these owls vulnerable to vehicle collisions. The overall population size may be larger than previously thought, not with standing the high mortalities already recorded. The small patches of viable habitat in the study area remains suitable for the breeding of the two grassland owl species allowing for such high densities to occur in the area. The Grass Owl, nonetheless, remains severely threatened as it already occurs as a high priority species for conservation concern in the Gauteng Province. This study provides the first assessment of this owl species of this scale in South Africa and this will ultimately promote the long-term survival of these owls. / Dr. V. Wepener

Rodents often colonise agricultural lands and become pests that cause economic loss and crop damage. Eradicating or regulating pest numbers has economic and environmental costs and has always been of great interest to farmers and nature conservationists. To reduce rodent numbers poison baits are used more often than biological control. However, poisoning has adverse environmental impacts and ignores the underlying biological factors that influence pest abundance. This study examined the interactions of the common rat species of oil palm plantations, namely Rattus rattus diardii, R. argentiventer and R. tiomanicus, with their food resource, habitat structure and introduced predators in an attempt to provide a better understanding and approach for their control. To investigate the interrelationships among rodents, owls and oil palms, rodent trapping was conducted simultaneously with pellet collection and assessment of the breeding of owls over six study plots and seven trapping intervals in one oil palm plantation. Trapping records suggested that relative abundances of rodent species differed in plots with palms of differing ages. There were more R. r. diardii as a proportion of the total captures in older palms (seven years old) while R. argentiventer was the most common rat captured in younger palms (three years old). The abundance of R. tiomanicus remained low throughout trapping sessions for palms of all ages. A numerical response of rats to fruit availability in older palms was demonstrated by a positive and significant correlation between the numbers of fruit bunches present and the total number of rats captured. This relationship was observed in both older and younger palms only for R. argentiventer but not R. r. diardii or R. tiomanicus in either age of palms. This suggests that the competitiveness of R. argentiventer may be higher than that of the other two species providing that there were no factors other than food availability that limit the numbers of other two species. However, the levels of damage to palm fruit were significantly correlated with the relative abundance of R. argentiventer only in younger palms, not in older ones where R. r. diardii were more abundant. The more terrestrial nature of R. argentiventer may have restricted their acquisition of food when the palms became taller. In addition to differences in feeding niche, habitat heterogeneity may also be important in determining the rat species compositions at different ages of palms. Vegetation cover may act as a refuge for rats; the overall occurrence of rats, and especially R. argentiventer, was positively correlated with vegetation cover and height, and even certain vegetation associations. This study supported the continued use of the barn owl Tyto alba javanica for biological control of rodent pests in the palm oil plantations. The numbers of different rat species consumed by owls, as measured by pellet numbers, were proportional to prey captures with R. r. diardii dominating the prey items. Weights and sexes of rats, based upon sizes of bones recovered from owl pellets, indicated that the birds did not preferentially prey on any size or sex classes of rats. Although there was no differential predation by the owls, a functional, and possibly a numerical, response of the birds to changes in rat numbers was demonstrated. A functional response of barn owls to prey abundance was evidenced by a significant positive relationship between the relative abundance of rats captured and numbers of pellets collected. Some form of numerical response of barn owls was suggested by higher breeding records when rat abundances were significantly higher. Since both functional and numerical responses are important determinants of whether predators are likely to be able to regulate prey numbers, the role of barn owls as a practical biological control agent in oil palm plantations was supported. This study suggested that the regulation of rodent pests in oil palm plantations should not be limited to chemical measures but can be complemented by other biological factors including interspecific interactions, manipulation of the availability and density of food and habitat structure, in addition to predation by barn owls. The findings suggested that an integrated approach to rodent control, considering all biological factors that influence rat numbers, should be properly applied if an environmentally friendly and possibly cost effective approach is to be applied for the palm oil industry.

La lutte contre les rongeurs est souvent un enjeu majeur dans les agroécosystèmes. Nous avons conduit une étude comparative dans des plantations de palmiers à huile dans les provinces de Riau et de Bangka en Indonésie. Dans les deux zones, des chouettes ont été introduites pour la lutte contre les rats ; toutefois, à Riau les rats sont maintenus à des niveaux de population acceptables sans recours au raticide, tandis qu’à Bangka les dégâts des rats sont très importants et l’usage de raticide intensif. Nous avons comparé ce deux systèmes en terme d’abondance et/ou de régime alimentaire de deux prédateurs, chouettes et petits carnivores. D’après nos résultats, les petits carnivores sont beaucoup plus abondants dans les plantations à Riau qu’à Bangka, et le chat léopard (Prionailurus bengalensis) est absent à Bangka tandis que cette espèce domine à Riau. Nos résultats suggèrent également que la prédation sur les rats par les chouettes et les petits carnivores serait moindre à Bangka qu’à Riau. D’une manière générale, cette étude confirme l’hypothèse selon laquelle les petits carnivores, notamment les chats léopard, joueraient un rôle important dans la lutte contre les rats en palmeraies. Par ailleurs, nous avons analysé la distribution spatiale des petits carnivores en plantation. Nos résultats suggèrent que, bien que l’habitat palmeraie soit largement utilisé la nuit par certains petits carnivores comme le chat leopard, qui y trouve une abondante ressource alimentaire, la plupart des espèces sont dépendantes de la forêt. Les gestionnaires des palmeraies devraient adapter leurs pratiques, afin de favoriser les petits carnivores dans une perspective de lutte contre les rats. / Rodent pest control is often a major issue in agroecosystems. We conducted a 3-year comparative study (2010-2012) in oil palm plantations in Riau and Bangka provinces, in Indonesia: in both areas barn owls have been introduced for rat control, and were at least as abundant in Bangka plantations than in Riau, but in Riau rat populations have been maintained at an acceptable level without the use of rodenticide, whereas in Bangka intensive rodenticide applications did not prevent high levels of rat damage. We compared these two contrasting systems in terms of predator community (barn owls and small carnivores) abundance and/or diet. We found that small carnivores were much more abundant in Riau plantations than in Bangka, and that the leopard cat (Prionailurus bengalensis) was the dominant species in Riau while absent from Bangka. Our results on diet suggested that rat prey intake from barn owls and from the small carnivore community would be less in Bangka plantations than in Riau. Broadly, our results suggest that small carnivores, notably the leopard cat, play an important role in rodent control. In addition, we investigated spatial distribution of small carnivores within the oil palm habitat. Our results support the hypothesis that, although the oil palm may be habitable for some small carnivore species such as the leopard cat, where they supposedly forage at night, most species still need forest for their survival in oil palm landscapes. Oil palm plantations managers should adapt agricultural practices and land-use to enhance small carnivores, with the view to improve rodent control.

The presented thesis compares chosen energy industry sectors of the Czech Republic and Federal Republic of Germany and more concretely analyses the degree of energy security of both countries within the context European region. Theoretical background is based on the concurrence of neorealism with neoliberalism and can be identified as main driver of the European energy sector. The thesis had been written as a response to an unexpected shift of German energy policy from fossil towards renewable resources. This change sparked broad public discussion which questioned these concrete steps of German government with regard to the country's energy security. The author of this thesis is, however, trying to provide the point that the development of the European energy towards renewable energy, as well as the finalization of the single energy market will in the long run substantially improve individual and collective energy security of all member states.

Premature loss of capacity, mode of partial charge, additives, negative electrode, lead acid battery, lead-acid battery cycling, hybrid electric vehicle, traction battery, ebonex, titanium dioxide

new city part, park vegetation

Telemetry system, Optimisation, Sensoric networks, Smart Grid, Internet of Things, Sensors, Information security, Cryptography, Cryptography algorithms, Cryptosystem, Confidentiality, Integrity, Authentication, Data freshness, Non-Repudiation.