Les ongulés augmentent en nombre depuis une trentaine d’années dans l’ensemble de l’Europe, avec des répercussions en terme d’épidémiologie et de gestion forestière. Par conséquent, ces espèces sont de plus en plus contraintes à partager leur habitat avec d’autres espèces d’ongulés. Selon l’habitat disponible (constitué par les ressources et conditions d’un environnement donné), et pour répondre aux besoins des individus liés entre autre à leur morpho physiologie mais aussi aux contraintes énergétiques et de mobilité, les animaux vont sélectionner des ressources, pour s’alimenter et se protéger, ce qui aura des conséquences directes sur leur utilisation de l’espace. Ces mécanismes de sélection de l’habitat auront des répercussions à la fois sur la dynamique des populations, parfois via un impact sur la performance des individus, mais aussi sur la dynamique des communautés végétales. Les changements dans la survie ou la reproduction des animaux modifieront la densité des populations présentes (soit les conditions de l’habitat). De même, les conséquences de la sélection des ressources par les herbivores modifieront les ressources directement disponibles. En retour, les individus changeront les mécanismes de sélection de l’habitat. Cette thèse a pour but d’étudier les interactions entre le cerf et le chevreuil dans une réserve de chasse et de faune sauvage (RNCFS) dans les Vosges du Nord afin notamment de définir s’il existe une compétition entre les deux modèles d’étude. Nous aborderons la question du point de vue individuel par suivi télémétrique (GPS) mais aussi du point de vue populationnel. Les objectifs sont (1) décrire l’utilisation de l’espace par les deux herbivores et notamment les variations spatiales et temporelles de l’utilisation des ressources, (2) comprendre les mécanismes de sélection des ressources et la distribution spatiale des deux espèces d’ongulés les unes par rapport qui peuvent expliquer les patrons d’utilisation de l’espace observe, (3) déterminer les conséquences de la sélection et de l’utilisation de l’habitat des herbivores sur la dynamique des populations et la composition floristique du site. Les résultats de cette thèse nous ont permis de mieux comprendre les patrons et les conséquences des interactions entre le cerf et le chevreuil et pourront être appliqués à la gestion de la faune sauvage et de la forêt / European ungulates have increased in number in the last thirty years, with serious impacts on forests and diseases spread. As a consequence, each ungulate species is more and more constrained to share resources with other species. Individuals’ energetic needs are linked to their morpho-physiology and the energetic and mobility constraints they are facing. To respond to these needs, and depending on the available habitat (resources and conditions in a given environment), animals select food and protection resources, a process that have direct consequences on individuals space use. These mecanisms of habitat selection also have consequences on population dynamics and individual performance, as well as on vegetation dynamics. Changes in animal survival or reproduction efficiency can alter population density, thus habitat conditions. In the same maner, changes in vegetation dynamics can modify resources that are directly available for herbivorous. The aim of this thesis was to study the interactions between two ungulates, red deer and roe deer, in a French National hunting and wildlife reserve (the North of the Vosges region), in particular to determine whether they are in competition. This will be done at the individual scale with telemetric data (GPS) and at population scale. The objectives were (1) to describe their habitat use and its spatiotemporal variations, (2) to understand habitat selection mecanisms and spatial distribution of both species that could explain the observed patterns of habitat use, (3) to determine the impacts of such habitat use and selection on population dynamics and on vegetation composition. The results of this work enabled us to better understand patterns and consequences of the interaction between red deer and roe deer, with possible applications in forest and wildlife management

A study of habitat selection by large wild ungulates was carried out on a 50 cm2 area in the sub-tropical Lowveld region of eastern Transvaal province, South Africa. Estimations were made of herbaceous forage net productivity and ungulate secondary productivity on the same area. Fourteen vegetation types, varying in composition and structure from open savanna to dense woodland, were delineated by association analysis. Structural and vegetational characteristics which were considered to influence ungulate distribution were measured within each vegetation type. The study area supported resident populations of seven ungulate species during the wet season; drv season densities were higher due to population influxes from surrounding areas. Densities ranged from 13 to 67 animals per km2, with impala making up from 40 to 70 percent of the total population, wildebeest 10 to 40 percent, and lesser proportions of giraffe, zebra, kudu, warthog and waterbuck. Savanna vegetation types supported total densities of up to 185 animals/km2, while wooded types support fewer animals. Waterbuck were the most selective of the ungulates and concentrated mainly in the riparian woodland. Wildebeest, zebra and giraffe made variable use of savanna and open woodland types. Warthog preferred savanna types and avoided woodland. Impala were less selective, and kudu showed no habitat preferences. Ungulate distribution was related to several habitat characteristics, and the key factors were found to differ in each case. Each species had a unique combination of habitat characteristics to which it responded in linear fashion, and this was considered to be the way in which ungulates avoided competition by achieving spatial separation. Herbaceous forage standing crops and net production were functions of vegetation composition, soil types, rainfall and extent of ungulate utilization. Standing crops ranged from 350 to 4104 kgs/ha air-dried forage. Net primary production ranged from zero to 2719 kgs/ha; vegetation types on sandy soils did not produce in years with poor precipitation. Ungulates consumed about one-fourth of the herbaceous net primary production during the wet season and more than four-fifths during the course of a full year. Ungulate biomass on the area averaged about 40 kg/ha during the wet season and 65 kg/ha in the dry season, but biomasses varied a great deal with vegetation type, ungulate population species coMposition and seasonal densities. Ungulate secondary product ion varied correspondingly and ranged from 1.3 x 10-3 kcal/m2 per day to 4.8 x 10-3 kcals/m2 per day. Overall secondary production rate for the 2-year study period was 0.97 kcals/m2 per year, produced from a mean standing crop of 7.46 kcal/m2.

The objectives of my research were twofold: 1) to evaluate new technologies (camera traps and a new type of GPS collar) for studying large mammals in tropical forests, and 2) to study the ecology of the lowland tapir (Tapirus terrestris) in the Peruvian Amazon. Camera traps proved to be an efficient tool for mammal inventories in tropical forests. They recorded 24 out of 28 terrestrial medium and large sized mammal species with a survey effort of 2340 camera days. Camera traps were also able to reveal important information on habitat use, activity patterns and the use of mineral licks for five Amazonian ungulate species. There was a high spatial overlap between all the species with the grey brocket deer being the only species that was restricted to terra firme forest. White-lipped peccaries, tapirs and red brocket deer frequently used mineral licks, whereas collared peccaries and grey brocket deer were hardly ever observed at licks. A new type of GPS collar (TrackTag) tested in this study performed well under the dense canopy of a tropical forest. Position success rates of 87% for stationary collars and 48% for collars placed on tapirs were comparable to data obtained with GPS collars in temperate forests. The mean location error for stationary collars inside the forest was 28.9 m and the 95% error was 76.8 m. GPS collars placed on six tapirs for seven to 182 days showed home range sizes of 102 to 386 hectares. Tapirs were mainly nocturnal and areas used for foraging during the night differed from resting sites used during the day. Tapirs could walk up to 10 km to visit a mineral lick. Visits were irregular at intervals of a few days up to 36 days. The analysis of 135 tapir dung samples showed that tapirs ingest seeds of over 120 plant species. Seeds were found throughout the year but monthly species diversity was related to fruit availability. The size distribution of ingested seeds was related to availability. Most seeds were less then 10 mm wide, but seeds up to 25 mm were found. Both camera traps and TrackTag GPS collars greatly increased the possibilities for studying large rainforest mammals. The two technologies collect complementary information and each one is suited for a different set of questions.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 5 uppsatser.

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv., 2003. / Härtill 5 uppsatser.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 143-164). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 143-164). Also available on the Internet.

A herbivoria por grandes mamíferos é um fator decisivo no direcionamento de comunidades vegetais, influenciando o crescimento, sobrevivência e reprodução das plantas. Os ungulados, quando exóticos, podem impactar os ecossistemas diferentemente de herbívoros nativos, gerando maiores efeitos nas comunidades de plantas. Os objetivos deste estudo foram avaliar se a presença de búfalos (densidade de 1 animal/ha) impacta as assembléias de plântulas e de arbustos numa floresta estacional semidecídua no sul do Brasil, além de inferir consequências para a manutenção da comunidade vegetal. Para isso realizamos duas abordagens no município de Sentinela do Sul: na primeira, estabelecemos um experimento de exclusão de bubalinos (duração de 14 meses) e na segunda, comparamos três áreas com presença e protegidas desses herbívoros por três e dez anos. Em ambas as abordagens, registramos as seguintes variáveis ecológicas: riqueza, altura média de plantas, cobertura vegetal, diversidade (Shannon), e biomassa. No experimento de exclusão, nenhuma das variáveis apresentou diferenças significativas perante presença e ausência de búfalos (após 14 meses). Na comparação das três áreas as comunidades vegetais mostraram diferenças qualitativas (composição de espécies) no contraste presença versus dez anos de exclusão de búfalos, e as variáveis riqueza e altura média sofreram, respectivamente, significativos incremento e decréscimo. A diferença observada para o incremento de diversidade de zero a dez anos de exclusão foi marginalmente significativa e a compactação do solo apresentou decréscimo em função do tempo de exclusão do gado. Portanto , os resultados do presente trrabalho indicam que as manchas florestais não respondem à remoção de búfalos em baixas densidades no curto prazo e, na ausência de grandes herbívoros, a floresta tende a incrementar sua complexidade via aumento de riqueza e diversidade. / Herbivory by large mammals is a key factor in plant communities, and has effects on growth, survival and reproduction of plants. Ungulates, when exotic, impact ecosystems in a different way compared to the native ones, and may have a more pronounced effect on plant communities. In this study we evaluated buffalo (1 animal/ha density) impact on the seedling and shrub assemblages in a semideciduous seasonal forest in southern Brazil and checked if such impact would affect plant community maintainability. To address these aims we conducted two studies in Sentinela do Sul County: 1. we established a buffalo exclusion experiment (during 14 months) and 2. compared three areas with presence and protected against these herbivores for three and ten years. In both studies, we measured the following ecological variables: plant cover, richness, diversity (Shannon), biomass and average height. In the exclusion experiment, any ecological variable showed significant differences between buffalo presence and absence plots. When the three areas were compared, the communities showed qualitative differences (species composition) in the contrast presence versus ten years of buffalo exclusion, and richness and average height showed, respectively, increase and decrease. The difference observed for an increase of diversity between zero and ten years exclusion was marginally significant, and soil compactation showed retraction in relation to livestock exclusion time. We conclude that forest spots don’t answer in short-term to low densities buffalo removal and, in the absence of large herbivores, the forest tends to develop its complexity by richness and diversity increase, in a long-term basis.

A herbivoria por grandes mamíferos é um fator decisivo no direcionamento de comunidades vegetais, influenciando o crescimento, sobrevivência e reprodução das plantas. Os ungulados, quando exóticos, podem impactar os ecossistemas diferentemente de herbívoros nativos, gerando maiores efeitos nas comunidades de plantas. Os objetivos deste estudo foram avaliar se a presença de búfalos (densidade de 1 animal/ha) impacta as assembléias de plântulas e de arbustos numa floresta estacional semidecídua no sul do Brasil, além de inferir consequências para a manutenção da comunidade vegetal. Para isso realizamos duas abordagens no município de Sentinela do Sul: na primeira, estabelecemos um experimento de exclusão de bubalinos (duração de 14 meses) e na segunda, comparamos três áreas com presença e protegidas desses herbívoros por três e dez anos. Em ambas as abordagens, registramos as seguintes variáveis ecológicas: riqueza, altura média de plantas, cobertura vegetal, diversidade (Shannon), e biomassa. No experimento de exclusão, nenhuma das variáveis apresentou diferenças significativas perante presença e ausência de búfalos (após 14 meses). Na comparação das três áreas as comunidades vegetais mostraram diferenças qualitativas (composição de espécies) no contraste presença versus dez anos de exclusão de búfalos, e as variáveis riqueza e altura média sofreram, respectivamente, significativos incremento e decréscimo. A diferença observada para o incremento de diversidade de zero a dez anos de exclusão foi marginalmente significativa e a compactação do solo apresentou decréscimo em função do tempo de exclusão do gado. Portanto , os resultados do presente trrabalho indicam que as manchas florestais não respondem à remoção de búfalos em baixas densidades no curto prazo e, na ausência de grandes herbívoros, a floresta tende a incrementar sua complexidade via aumento de riqueza e diversidade. / Herbivory by large mammals is a key factor in plant communities, and has effects on growth, survival and reproduction of plants. Ungulates, when exotic, impact ecosystems in a different way compared to the native ones, and may have a more pronounced effect on plant communities. In this study we evaluated buffalo (1 animal/ha density) impact on the seedling and shrub assemblages in a semideciduous seasonal forest in southern Brazil and checked if such impact would affect plant community maintainability. To address these aims we conducted two studies in Sentinela do Sul County: 1. we established a buffalo exclusion experiment (during 14 months) and 2. compared three areas with presence and protected against these herbivores for three and ten years. In both studies, we measured the following ecological variables: plant cover, richness, diversity (Shannon), biomass and average height. In the exclusion experiment, any ecological variable showed significant differences between buffalo presence and absence plots. When the three areas were compared, the communities showed qualitative differences (species composition) in the contrast presence versus ten years of buffalo exclusion, and richness and average height showed, respectively, increase and decrease. The difference observed for an increase of diversity between zero and ten years exclusion was marginally significant, and soil compactation showed retraction in relation to livestock exclusion time. We conclude that forest spots don’t answer in short-term to low densities buffalo removal and, in the absence of large herbivores, the forest tends to develop its complexity by richness and diversity increase, in a long-term basis.

A herbivoria por grandes mamíferos é um fator decisivo no direcionamento de comunidades vegetais, influenciando o crescimento, sobrevivência e reprodução das plantas. Os ungulados, quando exóticos, podem impactar os ecossistemas diferentemente de herbívoros nativos, gerando maiores efeitos nas comunidades de plantas. Os objetivos deste estudo foram avaliar se a presença de búfalos (densidade de 1 animal/ha) impacta as assembléias de plântulas e de arbustos numa floresta estacional semidecídua no sul do Brasil, além de inferir consequências para a manutenção da comunidade vegetal. Para isso realizamos duas abordagens no município de Sentinela do Sul: na primeira, estabelecemos um experimento de exclusão de bubalinos (duração de 14 meses) e na segunda, comparamos três áreas com presença e protegidas desses herbívoros por três e dez anos. Em ambas as abordagens, registramos as seguintes variáveis ecológicas: riqueza, altura média de plantas, cobertura vegetal, diversidade (Shannon), e biomassa. No experimento de exclusão, nenhuma das variáveis apresentou diferenças significativas perante presença e ausência de búfalos (após 14 meses). Na comparação das três áreas as comunidades vegetais mostraram diferenças qualitativas (composição de espécies) no contraste presença versus dez anos de exclusão de búfalos, e as variáveis riqueza e altura média sofreram, respectivamente, significativos incremento e decréscimo. A diferença observada para o incremento de diversidade de zero a dez anos de exclusão foi marginalmente significativa e a compactação do solo apresentou decréscimo em função do tempo de exclusão do gado. Portanto , os resultados do presente trrabalho indicam que as manchas florestais não respondem à remoção de búfalos em baixas densidades no curto prazo e, na ausência de grandes herbívoros, a floresta tende a incrementar sua complexidade via aumento de riqueza e diversidade. / Herbivory by large mammals is a key factor in plant communities, and has effects on growth, survival and reproduction of plants. Ungulates, when exotic, impact ecosystems in a different way compared to the native ones, and may have a more pronounced effect on plant communities. In this study we evaluated buffalo (1 animal/ha density) impact on the seedling and shrub assemblages in a semideciduous seasonal forest in southern Brazil and checked if such impact would affect plant community maintainability. To address these aims we conducted two studies in Sentinela do Sul County: 1. we established a buffalo exclusion experiment (during 14 months) and 2. compared three areas with presence and protected against these herbivores for three and ten years. In both studies, we measured the following ecological variables: plant cover, richness, diversity (Shannon), biomass and average height. In the exclusion experiment, any ecological variable showed significant differences between buffalo presence and absence plots. When the three areas were compared, the communities showed qualitative differences (species composition) in the contrast presence versus ten years of buffalo exclusion, and richness and average height showed, respectively, increase and decrease. The difference observed for an increase of diversity between zero and ten years exclusion was marginally significant, and soil compactation showed retraction in relation to livestock exclusion time. We conclude that forest spots don’t answer in short-term to low densities buffalo removal and, in the absence of large herbivores, the forest tends to develop its complexity by richness and diversity increase, in a long-term basis.