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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Space use pattern, dispersal and social organisation of the raccoon dog (Nyctereutes procyonoides), an invasive, alien canid in Central Europe / Raumnutzung, Ausbreitung und Sozialsystem des Marderhundes (Nyctereutes procyonoides), eines invasiven, allochthonen Kaniden in Zentraleuropa

Drygala, Frank 14 December 2009 (has links) (PDF)
Abstract Between October 1999 and October 2003, 30 adult and 48 young (< 1 year) raccoon dogs (Nyctereutes procyonoides) were monitored using radio-telemetry in an area of Germany which has been occupied by this invasive alien species since the early 1990s. Additionally, three pairs of raccoon dogs were observed by continuous radio-tracking during the first six weeks after parturition in 2003. Furthermore 136 raccoon dog pubs were ear-tagged between June 1999 and August 2006. No adult animals dispersed from the area during the study period and home ranges tended to be used for several years, probably for life. The average annual home range size, calculated using 95% fixed kernel, was 382.2 ha ± 297.4 SD for females (n = 30 seasonal home ranges) and 352.4 ha ± 313.3 SD for males (n = 32 seasonal home ranges). Paired raccoon dogs had home ranges of similar size, with pair sharing the same area all year round. Raccoon dogs occupied large core areas (85% kernel) covering 81.2% of their home ranges. The home ranges were at their smallest during the mating season. The slightly larger size of home ranges in winter suggests that, due to the temperate climate, raccoon dogs do not hibernate in Germany. Males and females formed a long-term (probably lifelong) pair bond. Same-sex neighbours ignored each other and even adjacent males/females showed neither preference nor avoidance. Thus, it can be assumed that the raccoon dog in Central Europe is monogamous without exclusive territories, based on the results of home range overlap analysis and interaction estimations. Habitat composition within home ranges and within the whole study area was almost equal. Although, percentage shares of farmland and meadow was 16.35% smaller and 12.06% higher within the home ranges, respectively. All nine habitat types (farmland, forest, settlement, water, meadows, maize fields, small woods, reeds and hedges) were used opportunistically by raccoon dogs. No significant, recognisable difference for habitat preferences between seasons was detected. Male and female raccoon dog showed equal habitat preference pattern. A comparison of active and inactive locations in different habitats found no remarkable differences. Habitat composition of individual home ranges was used to classify animals. If the percentage of forest within a home range exceeded 50% the individual was classified as a ‘forest type’ raccoon dog. If the percentage of forest habitats within a home range was less than 5%, the share of pastureland was mean 81.82% ± 16.92 SD. Consequently the individual was classified as a ‘agrarian type’ raccoon dog. Neither habitat preference nor habitat selection process differed between the two ‘types’. Habitat use and preference is discussed with relation to the ability of the raccoon dog to expand its range towards Western Europe. Males spent noticeably more time (40.5% of the time ±11.7 SD) alone with the pups than females (16.4% of the time ±8.5 SD). Females had noticeably larger 95% kernel home ranges (98.24 ha ±51.71 SD) than males (14.73 ha ±8.16 SD) and moved much longer daily distances (7,368 m ±2,015 SD) than males (4,094 m ±2,886 SD) in six weeks postpartum. The raccoon dogs being studied left the breeding den in the 6th week after the birth of the pups. In situ video observation showed that the male carried prey to the den to provide the female and the litter with food. A clear division of labour took place among parents during the period in which the pups were nursed: males guarded the litter in the den or in close vicinity of it, while the females foraged to satisfy their increased energy requirements. There were relocations of 59 (43.4%) ear-tagged young racoon dogs and mean distance from marking point was 13.5 km ±20.1 SD. Dispersal mortality rate was 69.5% among young raccoon dogs. Most animals (55.9%) were recovered nearer than 5 km from the marking point, whereas only 8.5% relocations were recorded further than 50 km from the marking point. There was no difference in the distances of relocations between sexes. Most (53.7%) relocations of ear-tagged young raccoon dogs were in August and September and, only 34.1% were recorded from October to April. Hunting (55 %) and traffic (27 %) were the major mortality factors. Radio-collared young raccoon dogs generally dispersed between July and September. The mean natal home range size (MCP 100%) with and without excursions was 502.6 ha ±66.4 SD (n = 9) and 92.1 ha ±66.4 SD (n = 17), respectively. There were no differences between sexes in the month of dispersal. The direction of travel for dispersing animals appeared to be random, with distances from 0.5 km to 91.2 km. A highly flexible dispersing behaviour is certainly one of the reasons which contribute to the high expansion success of the species.
2

Space use pattern, dispersal and social organisation of the raccoon dog (Nyctereutes procyonoides GRAY, 1834) an invasive, alien canid in Central Europe

Drygala, Frank 16 August 2010 (has links) (PDF)
Between October 1999 and October 2003, 30 adult and 48 young (< 1 year) raccoon dogs (Nyctereutes procyonoides) were monitored using radio-telemetry in an area of North-East Germany which has been occupied by this invasive alien species since the early 1990s. Additionally, three pairs of raccoon dogs were observed by continuous radio-tracking during the first six weeks after parturition in 2003. Furthermore 136 raccoon dog pubs were ear-tagged between June 1999 and August 2006. No adult animals dispersed from the area during the study period and home ranges tended to be used for several years, probably for life. The average annual home range size, calculated using 95% fixed kernel, was 382.2 ha ± 297.4 SD for females (n = 30 seasonal home ranges) and 352.4 ha ± 313.3 SD for males (n = 32 seasonal home ranges). Paired raccoon dogs had home ranges of similar size, with pair mates sharing the same area all year round. Raccoon dogs occupied large core areas (85% kernel) covering 81.2% of their home ranges. The home ranges were at their smallest during the mating season. The slightly larger size of home ranges in winter suggests that, due to the temperate climate, raccoon dogs do not hibernate in Germany. Males and females formed a long-term (probably lifelong) pair bond. Same-sex neighbours ignored each other and even adjacent males/females showed neither preference nor avoidance. Thus, it can be assumed that the raccoon dog in Central Europe is monogamous without exclusive territories, based on the results of home range overlap analysis and interaction estimations. Habitat composition within home ranges and within the whole study area was almost equal. Although, percentage shares of farmland and meadow was 16.35% smaller and 12.06% higher within the home ranges, respectively. All nine habitat types (farmland, forest, settlement, water, meadows, maize fields, small woods, reeds and hedges) were used opportunistically by raccoon dogs. No significant, recognisable difference for habitat preferences between seasons was detected. Male and female raccoon dog showed equal habitat preference pattern. A comparison of active and inactive locations in different habitats found no remarkable differences. Habitat composition of individual home ranges was used to classify animals. If the percentage of forest within a home range exceeded 50% the individual was classified as a ‘forest type’ raccoon dog. If the percentage of forest habitats within a home range was less than 5%, the share of pastureland was mean 81.82% ± 16.92 SD. Consequently the individual was classified as a ‘agrarian type’ raccoon dog. Neither habitat preference nor habitat selection process differed between the two ‘types’. Habitat use and preference is discussed with relation to the ability of the raccoon dog to expand its range towards Western Europe. Males spent noticeably more time (40.5% of the time ±11.7 SD) alone with the pups than females (16.4% of the time ±8.5 SD). Females had noticeably larger 95% kernel home ranges (98.24 ha ±51.71 SD) than males (14.73 ha ±8.16 SD) and moved much longer daily distances (7,368 m ±2,015 SD) than males (4,094 m ±2,886 SD) in six weeks postpartum. The raccoon dogs being studied left the breeding den in the 6th week after the birth of the pups. In situ video observation showed that the male carried prey to the den to provide the female and the litter with food. A clear division of labour took place among parents during the period in which the pups were nursed: males guarded the litter in the den or in close vicinity of it, while the females foraged to satisfy their increased energy requirements. There were relocations of 59 (43.4%) ear-tagged young raccoon dogs and mean distance from marking point was 13.5 km ±20.1 SD. Dispersal mortality rate was 69.5% among young raccoon dogs. Most animals (55.9%) were recovered nearer than 5 km from the marking point, whereas only 8.5% relocations were recorded further than 50 km from the marking point. There was no difference in the distances of relocations between sexes. Most (53.7%) relocations of ear-tagged young raccoon dogs were in August and September and, only 34.1% were recorded from October to April. Hunting (55 %) and traffic (27 %) were the major mortality factors. Radiocollared young raccoon dogs generally dispersed between July and September. The mean natal home range size (MCP 100%) with and without excursions was 502.6 ha ±66.4 SD (n = 9) and 92.1 ha ±66.4 SD (n = 17), respectively. There were no differences between sexes in the month of dispersal. The direction of travel for dispersing animals appeared to be random, with distances from 0.5 km to 91.2 km. A highly flexible dispersing behaviour is certainly one of the reasons which contribute to the high expansion success of the species.
3

Space use pattern, dispersal and social organisation of the raccoon dog (Nyctereutes procyonoides), an invasive, alien canid in Central Europe: Space use pattern, dispersal and social organisation of the raccoon dog (Nyctereutes procyonoides), an invasive, alien canid in Central Europe

Drygala, Frank 03 December 2009 (has links)
Abstract Between October 1999 and October 2003, 30 adult and 48 young (&amp;lt; 1 year) raccoon dogs (Nyctereutes procyonoides) were monitored using radio-telemetry in an area of Germany which has been occupied by this invasive alien species since the early 1990s. Additionally, three pairs of raccoon dogs were observed by continuous radio-tracking during the first six weeks after parturition in 2003. Furthermore 136 raccoon dog pubs were ear-tagged between June 1999 and August 2006. No adult animals dispersed from the area during the study period and home ranges tended to be used for several years, probably for life. The average annual home range size, calculated using 95% fixed kernel, was 382.2 ha ± 297.4 SD for females (n = 30 seasonal home ranges) and 352.4 ha ± 313.3 SD for males (n = 32 seasonal home ranges). Paired raccoon dogs had home ranges of similar size, with pair sharing the same area all year round. Raccoon dogs occupied large core areas (85% kernel) covering 81.2% of their home ranges. The home ranges were at their smallest during the mating season. The slightly larger size of home ranges in winter suggests that, due to the temperate climate, raccoon dogs do not hibernate in Germany. Males and females formed a long-term (probably lifelong) pair bond. Same-sex neighbours ignored each other and even adjacent males/females showed neither preference nor avoidance. Thus, it can be assumed that the raccoon dog in Central Europe is monogamous without exclusive territories, based on the results of home range overlap analysis and interaction estimations. Habitat composition within home ranges and within the whole study area was almost equal. Although, percentage shares of farmland and meadow was 16.35% smaller and 12.06% higher within the home ranges, respectively. All nine habitat types (farmland, forest, settlement, water, meadows, maize fields, small woods, reeds and hedges) were used opportunistically by raccoon dogs. No significant, recognisable difference for habitat preferences between seasons was detected. Male and female raccoon dog showed equal habitat preference pattern. A comparison of active and inactive locations in different habitats found no remarkable differences. Habitat composition of individual home ranges was used to classify animals. If the percentage of forest within a home range exceeded 50% the individual was classified as a ‘forest type’ raccoon dog. If the percentage of forest habitats within a home range was less than 5%, the share of pastureland was mean 81.82% ± 16.92 SD. Consequently the individual was classified as a ‘agrarian type’ raccoon dog. Neither habitat preference nor habitat selection process differed between the two ‘types’. Habitat use and preference is discussed with relation to the ability of the raccoon dog to expand its range towards Western Europe. Males spent noticeably more time (40.5% of the time ±11.7 SD) alone with the pups than females (16.4% of the time ±8.5 SD). Females had noticeably larger 95% kernel home ranges (98.24 ha ±51.71 SD) than males (14.73 ha ±8.16 SD) and moved much longer daily distances (7,368 m ±2,015 SD) than males (4,094 m ±2,886 SD) in six weeks postpartum. The raccoon dogs being studied left the breeding den in the 6th week after the birth of the pups. In situ video observation showed that the male carried prey to the den to provide the female and the litter with food. A clear division of labour took place among parents during the period in which the pups were nursed: males guarded the litter in the den or in close vicinity of it, while the females foraged to satisfy their increased energy requirements. There were relocations of 59 (43.4%) ear-tagged young racoon dogs and mean distance from marking point was 13.5 km ±20.1 SD. Dispersal mortality rate was 69.5% among young raccoon dogs. Most animals (55.9%) were recovered nearer than 5 km from the marking point, whereas only 8.5% relocations were recorded further than 50 km from the marking point. There was no difference in the distances of relocations between sexes. Most (53.7%) relocations of ear-tagged young raccoon dogs were in August and September and, only 34.1% were recorded from October to April. Hunting (55 %) and traffic (27 %) were the major mortality factors. Radio-collared young raccoon dogs generally dispersed between July and September. The mean natal home range size (MCP 100%) with and without excursions was 502.6 ha ±66.4 SD (n = 9) and 92.1 ha ±66.4 SD (n = 17), respectively. There were no differences between sexes in the month of dispersal. The direction of travel for dispersing animals appeared to be random, with distances from 0.5 km to 91.2 km. A highly flexible dispersing behaviour is certainly one of the reasons which contribute to the high expansion success of the species.
4

Space use pattern, dispersal and social organisation of the raccoon dog (Nyctereutes procyonoides GRAY, 1834) an invasive, alien canid in Central Europe

Drygala, Frank 03 December 2009 (has links)
Between October 1999 and October 2003, 30 adult and 48 young (< 1 year) raccoon dogs (Nyctereutes procyonoides) were monitored using radio-telemetry in an area of North-East Germany which has been occupied by this invasive alien species since the early 1990s. Additionally, three pairs of raccoon dogs were observed by continuous radio-tracking during the first six weeks after parturition in 2003. Furthermore 136 raccoon dog pubs were ear-tagged between June 1999 and August 2006. No adult animals dispersed from the area during the study period and home ranges tended to be used for several years, probably for life. The average annual home range size, calculated using 95% fixed kernel, was 382.2 ha ± 297.4 SD for females (n = 30 seasonal home ranges) and 352.4 ha ± 313.3 SD for males (n = 32 seasonal home ranges). Paired raccoon dogs had home ranges of similar size, with pair mates sharing the same area all year round. Raccoon dogs occupied large core areas (85% kernel) covering 81.2% of their home ranges. The home ranges were at their smallest during the mating season. The slightly larger size of home ranges in winter suggests that, due to the temperate climate, raccoon dogs do not hibernate in Germany. Males and females formed a long-term (probably lifelong) pair bond. Same-sex neighbours ignored each other and even adjacent males/females showed neither preference nor avoidance. Thus, it can be assumed that the raccoon dog in Central Europe is monogamous without exclusive territories, based on the results of home range overlap analysis and interaction estimations. Habitat composition within home ranges and within the whole study area was almost equal. Although, percentage shares of farmland and meadow was 16.35% smaller and 12.06% higher within the home ranges, respectively. All nine habitat types (farmland, forest, settlement, water, meadows, maize fields, small woods, reeds and hedges) were used opportunistically by raccoon dogs. No significant, recognisable difference for habitat preferences between seasons was detected. Male and female raccoon dog showed equal habitat preference pattern. A comparison of active and inactive locations in different habitats found no remarkable differences. Habitat composition of individual home ranges was used to classify animals. If the percentage of forest within a home range exceeded 50% the individual was classified as a ‘forest type’ raccoon dog. If the percentage of forest habitats within a home range was less than 5%, the share of pastureland was mean 81.82% ± 16.92 SD. Consequently the individual was classified as a ‘agrarian type’ raccoon dog. Neither habitat preference nor habitat selection process differed between the two ‘types’. Habitat use and preference is discussed with relation to the ability of the raccoon dog to expand its range towards Western Europe. Males spent noticeably more time (40.5% of the time ±11.7 SD) alone with the pups than females (16.4% of the time ±8.5 SD). Females had noticeably larger 95% kernel home ranges (98.24 ha ±51.71 SD) than males (14.73 ha ±8.16 SD) and moved much longer daily distances (7,368 m ±2,015 SD) than males (4,094 m ±2,886 SD) in six weeks postpartum. The raccoon dogs being studied left the breeding den in the 6th week after the birth of the pups. In situ video observation showed that the male carried prey to the den to provide the female and the litter with food. A clear division of labour took place among parents during the period in which the pups were nursed: males guarded the litter in the den or in close vicinity of it, while the females foraged to satisfy their increased energy requirements. There were relocations of 59 (43.4%) ear-tagged young raccoon dogs and mean distance from marking point was 13.5 km ±20.1 SD. Dispersal mortality rate was 69.5% among young raccoon dogs. Most animals (55.9%) were recovered nearer than 5 km from the marking point, whereas only 8.5% relocations were recorded further than 50 km from the marking point. There was no difference in the distances of relocations between sexes. Most (53.7%) relocations of ear-tagged young raccoon dogs were in August and September and, only 34.1% were recorded from October to April. Hunting (55 %) and traffic (27 %) were the major mortality factors. Radiocollared young raccoon dogs generally dispersed between July and September. The mean natal home range size (MCP 100%) with and without excursions was 502.6 ha ±66.4 SD (n = 9) and 92.1 ha ±66.4 SD (n = 17), respectively. There were no differences between sexes in the month of dispersal. The direction of travel for dispersing animals appeared to be random, with distances from 0.5 km to 91.2 km. A highly flexible dispersing behaviour is certainly one of the reasons which contribute to the high expansion success of the species.
5

Fiabilité et problèmes de déploiement du codage réseau dans les réseaux sans fil / Reliability and deployment issues of network coding in wireless networks

Ageneau, Paul-Louis 28 February 2017 (has links)
Même si les réseaux de données ont beaucoup évolué au cours des dernières décennies, les paquets sont presque toujours transmis d’un nœud à l’autre comme des blocs de données inaltérables. Cependant, ce paradigme fondamental est aujourd’hui remis en question par des techniques novatrices comme le codage réseau, qui promet des améliorations de performance et de fiabilité si les nœuds sont autorisés à mixer des paquets entre eux. Les réseaux sans fil manquent de fiabilité en raison des obstacles ou interférences que subissent les liens sans fil, et ces problèmes peuvent empirer dans des topologies maillées avec de multiples relais potentiels. Dans ce travail, nous nous concentrons sur l’application du codage réseau intra-flux aux flux unicast dans les réseaux sans fil, avec pour objectif d’améliorer la fiabilité des transferts de données et de discuter des opportunités de déploiement et des performances. Tout d’abord, nous proposons une borne inférieure pour la redondance, puis un algorithme opportuniste distribué, pour adapter le codage aux conditions du réseau et permettre la livraison fiable des données dans un réseau sans fil maillé, tout en prenant en compte les besoins de l’application. En outre, puisque les opérations requises pour le codage réseau sont coûteuses en termes de calcul et de mémoire, nous étendons cet algorithme pour s’adapter aux contraintes physiques de chaque nœud. Ensuite, nous étudions les interactions du codage intra-flux avec TCP et son extension MPTCP. Le codage réseau peut en effet améliorer les performances de TCP, qui ont tendance à être plus faibles sur les liens sans fil, moins fiables. Nous observons l’impact des problèmes d’équité qui se posent quand des flux codés fonctionnent en parallèle avec des flux traditionnels non codés. Pour finir, nous explorons deux manières différentes d’améliorer les performances de MPTCP dans les environnements sans fil : le faire fonctionner sur du codage réseau, et implémenter directement le codage directement dans le protocole MPTCP tout en préservant sa compatibilité avec TCP / Even if packet networks have significantly evolved in the last decades, packets are still transmitted from one hop to the next as unalterable pieces of data. Yet this fundamental paradigm has recently been challenged by new techniques like network coding, which promises network performance and reliability enhancements provided nodes can mix packets together. Wireless networks rely on various network technologies such as WiFi and LTE. They can however be unreliable due to obstacles, interferences, and these issues are worsened in wireless mesh network topologies with potential network relays. In this work, we focus on the application of intra-flow network coding to unicast flows in wireless networks. The main objective is to enhance reliability of data transfers over wireless links, and discuss deployment opportunities and performance. First, we propose a redundancy lower bound and a distributed opportunistic algorithm, to adapt coding to network conditions and allow reliable data delivery in a wireless mesh. We believe that application requirements have also to be taken into account. Since network coding operations introduce a non negligible cost in terms of processing and memory resources, we extend the algorithm to consider the physical constraints of each node. Then, we study the interactions of intra-flow coding with TCP and its extension MPTCP. Network coding can indeed enhance the performances of TCP, which tends to perform poorly over lossy wireless links. We investigate the pratical impact of fairness issues created when running coded TCP flows besides legacy non-coded TCP flows. Finally, we explore two different ways to enhance the performance of MPCTP in wireless environments : running it over network coding, and implementing the coding process directly in MPTCP while keeping it fully TCP-compatible.

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