Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Blue manakin Chiroxiphia caudata is a bird with wide distribution in southern Atlantic forest, ranging from humid forests of the Serra do Mar to the deciduous forests of the Brazilian and Meridional highlands. Although the species is well known for its acrobatic displays, much of their behavior and ecology are unknown or poorly studied. Data about feeding behavior, use of the space and dispersal of seeds, and other results were treated in this dissertation. The study site includes the deciduous forest, far southern Atlantic Forest. Leks of Blue manakin were monitored throughout one year (2006-2007) and data structures of the environment were collected in 2009. These results were divided into four chapters (articles). The first is about the behavioral variation and the use of space throughout the reproductive period and non-reproductive period among three classes of individuals (adult males, young males and females). It is shown that there are differences in behavior patterns and use of space between the sexes and age groups, adult males being more active in the reproductive period and restricted to interior of the leks. Young males tend to live in the edge of territories of adults and they had fewer courtships and vocalizations. Females seem to prefer environments not used by males. The second chapter refers to the diet and seed dispersal. Blue manakin fed on more than 40 plants being that the species with the longest period of fruiting (e.g. Psychotria leiocarpa) or asynchronous (e.g. Ficus) were the most sought after. Besides, there was preference for berries, fruit and small seed sizes, dark-blue coloration, as well as species found in the lower strata of the forest. In relation to seed dispersal, Blue manakin was performed as good seed dispersers; it plays a different type of consumption throughout the year, depositing seeds at specific sites (perches of courtship and call) or random (perches of foraging) in the forest. The third chapter concerns the preference for the dance sites by males. In this study, raises the hypothesis that areas with more density of plants near the perches and attributes of trees that are used by Blue manakin would serve as an indication for adult males choose certain sites instead of others. Variables such as abundance, richness, plant height and number of horizontal branches in the perches of cutting were responsible for the presence of Blue manakin in these courtship sites. This fact would give more care against predators and to the quality of the cooperative and solo displays. The fourth discusses the potential effect of seed dispersal on the perches of courtship. Seedlings under the perches, the use of time by males at these sites and the total fruit consumed showed that C. caudata is effective disperser of species included in its diet. The final chapter chapter focuses on the foraging tactics of Blue manakin uses to capture the fruits of understory plants and test three hypotheses why the species foraging inside and/or outside the plants. / O Tangará Chiroxiphia caudata é um pássaro com ampla distribuição no sul da floresta atlântica, abrangendo desde florestas ombrófilas da serra do Mar até as florestas estacionais do planalto brasileiro e meridional. Embora a espécie seja bem conhecida por suas danças acrobáticas, muito do seu comportamento e ecologia são desconhecidos ou pouco estudados. Dados sobre o comportamento alimentar, uso do espaço e dispersão de sementes, foram tratados nesta dissertação. O local de estudo compreende a floresta estacional decidual, extremo sul da Floresta atlântica. Leques de tangarás foram monitorados ao longo de um ano (2006-2007) e dados referentes às estruturas do ambiente foram coletados em 2009. Esses resultados foram divididos em cinco capítulos (artigos). O primeiro capítulo trata sobre a variação comportamental e do uso do espaço ao longo do período reprodutivo e nãoreprodutivo entre três classes de indivíduos (machos adultos, machos jovens e fêmeas). Mostra-se que há diferenças quanto aos diferentes comportamentos e ao uso do espaço entre os sexos e classes etárias, sendo os machos adultos mais ativos no período reprodutivo e restritos ao interior do leque. Machos jovens tendem a viver mais na borda dos territórios dos adultos e a realizar menos cortejos e vocalizações. Fêmeas parecem preferir ambientes não utilizados pelos machos. O segundo capítulo refere-se à dieta e dispersão de sementes. O tangará alimentou-se de mais de 40 plantas. Além disso, houve preferências por bagas, frutos e sementes de tamanhos pequenos e de coloração azul-escura, bem como por espécies encontradas nos estratos mais baixos da floresta. Em relação à dispersão de sementes, o tangará se apresentou como bom dispersor de sementes, pois desempenha um tipo de consumo diferenciado ao longo do ano, depositando sementes em sítios específicos (poleiros de corte e de vocalização) ou em outros locais da floresta (poleiros de forrageamento) na floresta. Já o terceiro capítulo faz referência quanto a preferência por locais de dança pelos machos. Neste estudo levanta-se a hipótese que áreas com mais adensamento de plantas próximo aos poleiros e atributos das árvores que são utilizadas pelos tangarás, serviriam como indicativo para machos adultos escolher certos locais em relação a outros. Variáveis como abundância, riqueza, altura média das plantas e número de galhos horizontais nos poleiros de corte, foram responsáveis pela presença dos tangarás nesses locais de cortejo. O quarto capítulo trata do potencial efeito da dispersão de sementes sobre os poleiros de corte. Plântulas sob os poleiros, o uso do tempo dos machos nesses locais e o total de frutos consumidos, mostraram que C. caudata é efetivo dispersor das espécies pertencentes a sua dieta. O último capítulo trata sobre as táticas de forrageamento do tangará utiliza para capturar frutos de plantas de sub-bosque e levanta três hipóteses do por que a espécie forragearia frutos sobre e/ou fora das plantas.

Many studies show that large herbivores can have an important impact on the composition of vegetation. With the establishment of a year round, low density grazing regime, plant ecologists and nature managers expect that through selective grazing, herbivores will create a mosaic of different vegetation communities varying in structure and plant species composition. It is believed that such a mosaic in the end will guarantee a high degree of biodiversity. Grazing will, therefore, seem to be a suitable means to maintain grass. Also important is the ability of herbivores affect vegetation through endozoochory. In this thesis I have tried to find out what species of diet horses prefer regarding to plant species and what plant species they can spread through out endozoochory. I have compared this knowledge with the composition of pasture and meadow vegetation at the researched locality in Malenice and Hoslovice. With the purpose of finding out the preferences I established spots where I registered data on vegetation before pasture and the time intervals during the pasture. Afterwards, I researched the amount of sprouts and the composition of seedlings in excrements that I let germinate. I had to create phytocenologic shots from the pastures and meadows to compare the species of composition of grazed and...

Understanding of the diverse aspects affecting the regeneration ecology of species is crucial to make decisions regarding management and conservation strategies, especially in highly fragile and threatened ecosystem as the Neotropical savanna (cerrado) formations. Available knowledge of regeneration ecology of cerrado species is too limited to attain optimal or suitable management actions. The objectives of the present study were: i) analysis of the characteristic parameters of the anemochorous seed dispersal of study species Q. grandiflora, (ii) determine the spatial distribution of tree species Q. grandiflora for growth stages (seedlings to juveniles) and interrelations between the stages, and (iii) determining variables of the spatial distribution of recruitment of tree species A. tomentosum. The present study was conducted in the cerrado Aguara Ñu of the Mbaracayú Nature Forest Reserve located in the northeast of Paraguay. The cerrado Aguara Ñu is part of the Mbaracayú Biosphere Reserve and represents one of the most important ecoregions in the world, the cerrado ecosystem. The cerrado biome encompasses areas from northeastern to southwestern Brazil, eastern Bolivia, and northern Paraguay. It is characterized by the presence of high plant and animal biodiversity and also high endemism (Myers et al., 2000). Tree species Q. grandiflora and A. tomentosum are typical species of the cerrado formation. Based on the selected investigated regeneration cycle stages of study tree species Q. grandiflora and A. tomentosum, the present thesis describes the spatial analysis of recruitment of both study species and the anemochorous diaspore dispersal of tree species Q. grandiflora. The purpose of the present investigation is to address regeneration aspects not attained so far as certain seed dispersal aspects, such as seed densities and distances from conspecific adult trees and spatial arrangements of seedlings of species A. tomentosum. Results of the present study aim to contribute to existing information and at the same time provide new knowledge on ecological aspects so far not investigated. Research results on seed dispersal of tree species Q. grandiflora revealed that dispersal can be modeled by inverse modelling considering isotropy and lognormal density function presenting mean dispersal distances of 10.69 to 62.48 m. Estimations of the fruit production of a seed tree yielded a total 50671 to 70632 (DBH = 70 cm). Results of spatial arrangement of seedlings and juveniles revealed a significant distance effect to conspecific adult trees. Moreover, results also showed: (i) highest densities or intensities (m2) of seedlings (heights <50 cm) close to the conspecific adult trees and (ii) a shift of intensity of seedlings with increase of growth stage or size for tree species Q. grandiflora. Additionally, seedlings (up to 200 cm height) of study species Q. grandiflora indicated gradual decreasing clumping patterns and juveniles (200 – 500 cm height) presented clumping patterns. Modelling results of spatial patterns of seedlings (heights ≤ 200 cm) of study tree species A. tomentosum revealed aggregation patterns. Moreover, shade effect resulted to be a statistical significant factor for the establishment of seedlings of tree species A. tomentosum (p-value = 0.0266), whereas distance effect to seed tree resulted not significant (p-value= 0.4936). Considering the findings of seed dispersal and spatial patterns analysis of tree species Q. grandiflora and A. tomentosum some management aspects to be attained for conservation purposes are avoiding fragmentation of the ecosystem, management of the spatial and time fire frequency and maintain minimum amount of seed trees per unit area in order to guarantee successful recruitment.:1. Introduction 1 References 8 2. Materials and Methods 13 2.1 Characterization of the cerrado biome 13 2.2 Description of the study area and study sites 15 2.3 Characterization of the study tree species 23 2.3.1 Qualea grandiflora (Mart.) 23 2.3.2 Aspidosperma tomentosum (Mart.) 24 2.4 Principles and selection criteria 25 2.5 Data collection 26 2.5.1 Seed dispersal 26 2.5.2 Spatial patterns of plants 27 2.6 Data analysis 28 2.6.1 Statistical analysis of data 28 2.6.2 General statistical procedures of data analysis 30 2.6.3 Spatial point process analysis – Inverse modelling and spatial point patterns 31 2.6.4 Spatial point patterns analysis procedure 33 2.6.4.1 Descriptive statistics in spatial point patterns 36 2.6.4.1.1 Distance effect of seedlings from seed trees (rhohat function) 36 2.6.4.1.2 Pair correlation function (pcf) 36 2.6.4.2 Point process modelling 38 References 43 3. Seed dispersal of Qualea grandiflora (Mart.) 49 3.1 Introduction 49 3.2 Methodology 51 3.2.1 Data collection and seed trap design 51 3.2.1 Data analysis – inverse modelling 53 3.3 Results 58 3.3.1 Seed density 58 3.3.2 Inverse modelling results – seed production, dispersal and distances 60 3.3.2.1 Isotropic modelling 61 3.3.2.2 Anisotropic modelling 63 3.3.2.3 Statistical comparison isotropy vs. anisotropy 66 3.4 Discussion 67 3.4.1 Applied methodology for seed dispersal – trap design and inverse modelling 67 3.4.2 Seed dispersal modelling 69 3.5 Conclusion 74 References 75 4. Spatial analysis of Qualea grandiflora (Mart.) 80 4.1 Introduction 80 4.2 Methodology 82 4.2.1 Data collection – Field sampling 82 4.2.2 Data analysis 85 4.2.2.1 Spatial point pattern – Explorative analysis 85 4.2.2.2 Point process modelling (Poisson and Gibbs models) 87 4.2.3 Results 89 4.2.3.1 Spatial distribution of individuals of study species 89 4.2.3.2 Modelling distance effect of recruitment to adult trees 95 4.2.4 Discussion 102 4.2.4.1 Applied methodology for spatial analysis of study species 102 4.2.4.2 Spatial arrangement of study species 103 4.2.5 Conclusion 109 References 109 5. Spatial analysis of Aspidosperma tomentosum (Mart.)115 5.1 Introduction 115 5.2 Methodology 117 5.2.1 Data collection – Field sampling 117 5.2.2 Data analysis 120 5.2.2.1 Spatial point pattern – Explorative analysis 120 5.2.2.2 Point process modelling – Replicated point patterns 120 5.3 Results 123 5.3.1 Spatial distribution of natural regeneration of study species 123 5.3.2 Modelling shade and distance to seed tree effect on natural regeneration of study species 130 5.4 Discussion 133 5.4.1 Applied methodology for data collection and analysis 133 5.4.2 Spatial distribution of natural regeneration of study species 134 5.5 Conclusion 139 References 140 5. Concluding discussion and summary 146 6.1 Regeneration ecology of Qualea grandiflora and Aspidosperma tomentosum 146 6.1.1 Inferences on relation of seed dispersal and spatial distribution of recruitment of Qualea grandiflora 146 6.1.2 Inferences on spatial patterns of recruitment of Aspidoserma tomentosum 149 6.2 Management implications for Qualea grandiflora Aspidosperma tomentosum 150 6.3 Future research 153 6.4 Concluding summary 154 References 155

Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: This study tested the proposal that fleshy-fruited alien shrubs competed more effectively for avian dispersal services than indigenous shrubs. Several different quantitative measures of increasing complexity were applied to test bird foraging preferences for fruits of two established alien shrubs (Lantana camara, Solanum mauritianum), two emergent alien shrubs (Myoporum tenuifolium, Pittisporum undulatum) and two indigenous shrubs (Chrysanthemoides monilifera, Olea europaea subsp. africana). Overall the simplest quantitative measure, namely that of bird visitation frequency identified foraging preferences of individual bird species for fruits of alien and indigenous shrubs. Moreover, even the more complex measures of numbers of foraging birds, foraging times and products of these in the computed consumption intensity and seed dispersal efficiency were positively correlated to visitation frequency. There was a distinct preference of several, especially heavily fugivorous, bird species for fruits of established alien than indigenous shrubs and several moderately fugivorous bird species preferred fruits of emergent than established alien shrubs. Intricate photographic and experimental approaches were applied to obtain precise numerical data on seed removal rates by birds from the alien and indigenous shrubs. Deficiencies associated with the experimental approach included its inability to discriminate between asynchronous fruit production and fruit ripening, individual foraging bird species, and fruit consumption by other fruit foraging vertebrates. The advantages of the photographic approach were in its provision of a detailed permanent record of individual foraging bird species, their total numbers and precise foraging times and the proportions of whole fruits consumed, as well as other behavioural foraging traits. Tested also was the proposal that frugivorous birds remove larger amounts of fruits from plants with high fruit production and nutritional contents and that the germination of the bird-ingested seeds is enhanced. In compliance with this proposal, canopy fruit mass and monosaccharide content were all positively correlated with the total numbers of seeds removed by birds and viable seeds excreted by birds. Only defecated seeds of the indigenous C. monilifera and alien L. camara displayed enhanced germination following their ingestion by birds Seed dispersal distances of alien and indigenous shrubs by birds were estimated from published records of bird body masses, gut retention times of consumed seed and flight speeds. Estimated seed dispersal distances ranged between 0.41 and 0.81 km for the subset of heavily and moderately frugivorous bird species examined. However, their foraging distances derived from birdring recapture records were much greater, these peaking between 2.5 and 50 km in some heavily frugivorous bird species. It is concluded 1. that bird visitation frequency be applied as the most efficient and practical quantitative measure for gauging bird foraging preferences in future surveys which should involve large complements of indigenous, emergent and established alien species, 2. that flight speeds and gut passage times of ingested alien and indigenous seeds need to be measured in local bird species so long distance seed dispersal potentials can be more precisely determined and 3. that control measures should be focused on eradicating especially emergent alien species with fleshy fruits from urban environments to prevent their transport by birds into adjacent natural areas. / AFRIKAANSE OPSOMMING: Hierdie studie het die voorstel getoets dat uitheemse vlesige-vrug struike meer effektief kompeteer vir voël verspreidingsdienste as inheemse vlesige-vrug struike. Verskeie kwantitatiewe maatstawwe van toenemende kompleksiteit was toegepas om die voedingsvoorkeure van voëls vir vrugte van twee gevestigde uitheemse struike (Lantana camara, Solanum mauritianum), twee ontluikende uitheemse struike (Myoporum tenuifolium, Pittisporum undulatum) en twee inheemse struike (Chrysanthemoides monilifera, Olea europaea subsp. africana) te toets. Algeheel het die eenvoudigste kwantitatiewe maatstaf, naamlik voël besoek frekwensie, voedingsvoorkeure van individuele voël spesies vir vrugte van uitheemse en inheemse struike geïdentifiseer. Addisioneel het die meer komplekse maatstawwe soos voël getalle, voedings tye, asook produkte hiervan in die berekende verbruiks intensiteit en saadverspreiding effektiwiteit almal positiewe korrelasies met besoek frekwensie. Predominant vrugtevretende voël spesies het ‘n duidelike voorkeur getoon vir vrugte van gevestigde uitheemse eerder as inheemse struike. Verskeie meer gematigde vrugtevretende voël spesies het egter vrugte van ontluikende eerder as gevestigde uitheemse struike verkies. Ingewikkelde fotografiese en eksperimentele benaderings was gebruik om presiese numeriese data van saad verwyderingstempo’s deur voëls vanaf die bestudeerde struike te bekom. Tekortkominge geassosieerd met dié eksperimentele benadering sluit in die onvermoë om te onderskei tussen asinkrone vrug produksie en vrug rypwording, individuele kos soekende voël spesies, asook vrug verbruik deur ander vrugvretende werweldiere. Die voordele van die fotografiese benadering was die verskaffing van ‘n gedetailleerde permanente rekord van individuele kos soekende voël spesies, hul totale getalle, presiese voedingstye, proporsie heel vrugte verbruik, asook ander voedingsgedrag eienskappe. Ook getoets was die voorstel dat vrugtevretende voëls groter hoeveelhede vrugte verwyder van plante met hoë vrugproduksie en hoë nutriënt inhoud, en dat ontkieming van voëlingeneemde sade verhoogd is. In nakoming met die voorstel, was blaredak vrugte massa en monosakkaried inhoud albei positief gekorreleer met totale aantal sade verwyder deur voëls en lewensvatbare sade uitgeskei deur voëls. Slegs sade van die inheemse C. monilifera en die uitheemse L. camara het verhoogde ontkieming gewys na inname deur voëls. Saadverspreiding afstande van uitheemse asook inheemse struike deur voëls was bepaal vanaf gepubliseerde rekords van liggaams massa, saad behoud tye in die maag na inname, en vliegspoed. Beraamde saadverspreiding afstande het gestrek tussen 0.41 en 0.81 km vir dié subgroep van predominant en gematigde vrugtevretende voël spesies bestudeer. Nogtans was voedings afstande, afgelei van geringde voël hervangs rekords, veel groter, en het gepiek tussen 2.5 en 50 km vir sommige predominant vrugtevretende spesies. Gevolglik weet ons nou dat 1) voël besoek frekwensie toegepas kan word as die mees effektiewe en praktiese kwantitatiewe maatstaf vir die bepaling van voël voedings voorkeure in toekomstige opnames waar komplementêre groepe inheemse, ontluikende en gevestigde uitheemse spesies bestudeer word; 2) vliegspoed en maag passeer tye van ingeneemde uitheemse en inheemse sade gemeet moet word in plaaslike voël spesies sodat langafstand saadverspreiding potensiaal meer presies bepaal kan word; en 3) beheer maatstawwe moet fokus op die verwydering van spesifiek ontluikende uitheemse vlesige-vrug spesies vanuit stedelike omgewings, om sodoende saad vervoer deur voëls na naasliggende natuurlike areas the verhoed.

The Amazon rainforest harbors the planet's highest biodiversity among terrestrial ecosystems; however, the biology and ecology of most of its species are unknown. Niche partitioning is considered a key factor allowing species co-existence, especially for morphological similar species such as spiny rats of the genus Proechimys. I examined the extent to which habitat differentiation, species body mass, and diet could explain the community composition of small mammals at a site in the southeastern Amazon. Moreover, I radio-tagged sympatric species of Proechimys spp. and Mesomys stimulax (an arboreal spiny rat) to obtain detailed autoecology information, including habitat use and use of space. I found support for niche partitioning among species and associated small mammal species with distinct successional phases of gap dynamics. I also observed among Proechimys spp. a typical polygynous organization: females appeared to be territorial against females of any species of their genus; but male territories overlapped with those of several females. Mesomys stimulax showed evidence of monogamy and possible sociality, although sample sizes were small. To identify the importance of small mammals as seed disperser of Brazil nut seeds, I conduct experiments using a combination of fluorescent powder, seed exclosures, and track plates in forests with and without Brazil nut groves, and in forests with and without Brazil nut harvesting. Among small mammals, only Proechimys spp. removed, dispersed, and preyed upon Brazil nut seeds. Proechimys spp. sometimes scatterhoarded these seeds, and hence have the potential to play a significant role in recruiting new Brazil nut trees. I also trapped small mammals and measured forest structures on the same sites used for the seed dispersal experiment, to determine the ecological effects of Brazil nut harvest on small mammal communities; however, my results showed little evidence of changes associated with the seed exploitation. My results highlight the importance of habitat heterogeneity in structuring small mammal communities, and indicate that forest management practices that alter habitats, such as partial logging, also can be expected to alter small mammal composition and diversity. Proechimys spp. have the potential to play an important role in the ecological restoration of intensive exploited Brazil nut groves.

La biosphère traverse une crise de biodiversité pour laquelle les milieux insulaires sont l’épicentre. Les invasions biologiques y constituent l’un des principaux facteurs de forçage, notamment du point de vue de l’altération des mutualismes, pour le fonctionnement et le maintien des écosystèmes. Durant notre travail en Nouvelle-Calédonie, nous nous sommes intéressés à un groupe clé de voute pour le fonctionnement des écosystèmes, les fourmis, et leur implication vis-à-vis de la dispersion de graines (myrmécochorie). Nous avons réalisé la première identification de plantes autochtones myrmécochores, avec une prépondérance des espèces sur substrats ultramafiques. Puis, nous avons testé la dispersion par les fourmis sur ces substrats. Après avoir caractérisé les communautés selon un gradient de perturbation anthropique, nous avons évalué la dispersion et la contribution des fourmis invasives à ce service par rapport aux fourmis natives. Ainsi, Solenopsis geminata semble capable d'une meilleure dispersion que les espèces natives. A contrario, Wasmannia auropunctata exclue les espèces natives sans assurer de dispersion efficace. Dans le contexte d’un régime de perturbations intense, nos travaux illustrent une communauté néo-assemblée de fourmis, dominée par des exotiques dont certaines pourraient assurer un relai de fonction pour la dynamique des maquis. Nos travaux illustrent la « contexte dépendance » des impacts d’espèces invasives en fonction du niveau de perturbation anthropique. Ils permettent de discuter la contribution possible de ces fourmis pour la restauration après perturbation sur substrats ultramafiques, voire de leur valorisation en ingénierie écologique. / The biosphere is experiencing a biodiversity crisis, which for islands are the epicenter. Biological invasions are there, one of the main drivers, especially regarding the alteration of mutualistic relationships for the functioning and the maintenance of ecosystems. Thus, during our work in New Caledonia, we focused on a key group for ecosystem functions: ants, and their involvement in seed dispersal (myrmecochory). We carried out the first assessment of this mutualism in New Caledonia with the identification of indigenous myrmechorous plants, with a preponderance of species on ultramafic soils. Then, we evaluated the magnitude of seed dispersal by ants on these soils. After the characterisation of ant communities across an anthropic disturbance gradient, we evaluated seed dispersal capabilities of exotic ant compared to native ones. Solenopsis geminata appears to offer a more efficient seed dispersal than natives. On the other hand, Wasmannia auropunctata excludes native species without ensuring effective dispersal. In the context of an intense disturbance regime, our work illustrates a neo-assembled community of ants, dominated by exotic ones, some of which could provide a function relay with respect to maintaining the dynamic of maquis. Our work illustrates the “context dependency” of invasive species’ impacts as a function of anthropogenic disturbance’s level. It also discusses the possible contribution of these ants in a context of restoration after disturbance of habitats on ultramafic substrates, or even their use in ecological engineering program.

Orientador: Marco Aurélio Pizo Ferreira / Banca: Wesley Rorigues da Silva / Banca: Claudio José Von Zuben / Resumo: Os dispersores de sementes possuem um papel fundamental na ecologia e evolução das plantas de frutos carnosos, especialmente em ambientes tropicais onde mais de 70% das espécies lenhosas são dispersas por vertebrados. A recente perda destas interações causada pela ação antrópica pode acarretar importantes perdas de biodiversidade. Este trabalho visou identificar quais espécies de aves são potenciais dispersoras de sementes em uma Ilha continental da Mata Atlântica, com um alto grau de perturbação. De dezembro de 2005 a janeiro de 2007, foi realizado um levantamento da avifauna da Ilha Anchieta baseado no método de amostragem por pontos (n= 360), que foram distribuídos em três ambientes, Floresta Densa (FD), Floresta Rala (FR) e Campos Antrópicos (CA). Foram registradas 75 espécies de aves, distribuídas em 27 famílias e 12 categorias alimentares. Tyrannidae e Thraupidae foram as famílias melhor representadas, com 17 e 8 espécies, respectivamente. Os ambientes não apresentaram diferenças significativas em relação ao número de indivíduos, mas diferiram quanto ao número de espécies frugívoras, com 26, 24 e 29 espécies para FD, FR e CA, respectivamente. Frugívoros especialistas foram considerados raros. Com o registro das interações entre aves frugívoras e plantas em frutificação foi obtido um total de 1341 visitas completas em 303,6 h de observações a 16 espécies arbóreas. Vinte e cinco espécies de aves se alimentaram de frutos que variaram entre 4,0 e 19,8 mm de comprimento e entre 3,3 e 14,7 mm de largura. Os principais potenciais dispersores foram Turdus leucomelas, Saltator similis, Tachyphonus coronatus, Thraupis sayaca e Turdus albicollis. Assim, os frugívoros generalistas destacam-se como importantes dispersores na Ilha, pois levam sementes de espécies pioneiras para as áreas alteradas, acelerando a sucessão vegetacional, tendo um papel fundamental na recuperação de áreas degradadas. / Abstract: Seed dispersers play a key role in the ecology and evolution of fleshy-fruited plants; especially in tropical forests where from 70% to 90% of all woody species are dispersed by vertebrates. The recent disruption of these interactions caused by human activities may bring about a considerable loss of biodiversity. The aim of this study was to identify wich species are potencial seed dispersers in a highly perturbed continental Island of the Atlantic Forest. From December 2005 to January 2006, a survey using point-counts was carried out at the Anchieta Island to record the avifauna in 360 points-counts stations distributed in three successional stages: old fields (CA), early secondary forest (FR), old growth forest (FD). A total of 75 birds species was recorded, distributed over a range of 27 families and 12 diet categories. Tyrannidae and Thraupidae were the most abundant families, with 17 and 8 species, respectively. The three successional stages were not significantly different in bird abundance, but differed in number of frugivorous species, where 29 species were recorded at CA, 24 at FR, and 26 at FD. Specialized frugivorous were rare. To identify the frugivorous birds and their potential role as seed dispersers in the three successional stages, focal-individual observations were performed on fruiting plants. Sixteen plant species were observed during 303.6 plant-hours. Twenty-five bird species were observed consuming fruits in a total of 1341 visits to fruiting plants. Fruits averaged 4.0 e 19.8 mm length, and 3.3 e 14.7 mm width. The main potential seed dispersers were Turdus leucomelas, Saltator similis, Tachyphonus coronatus, Thraupis sayaca and Turdus albicollis. Thus, generalist frugivorous birds were considered main potential seed dispersers, which may play a important role in accelerating the plant regeneration process at Anchieta Island. / Mestre

Les agroécosystèmes sont des mosaïques d’espaces cultivés, d’espaces naturels et semi-naturels et d’infrastructures humaines fortement imbriqués et donc intrinsèquement liés et dépendants. Les espaces semi-naturels sont confinés généralement aux bordures de champs et aux bordures de route où se côtoient biodiversités végétales cultivées et sauvages. Cette thèse se concentre principalement sur la dispersion des graines de colza (Brassica napus L.) vers ces espaces qui peut conduire à la formation de populations de colza dites férales. A l’échelle d’un agroécosystème, l’étude de données génotypiques couplées à des méthodes d’assignations aux variétés commerciales existantes, a permis de mettre en évidence un lien entre la diversité variétale des champs de colza cultivés et la diversité variétale des populations férales de l’année suivante. De surcroît, l’étude de ces diversités variétales a montré que les champs ne sont pas des entités uniformes comportant des plantes d’une seule variété et que les populations férales accumulent les variétés au fil des années grâce aux apports annuels des champs récoltés, à la survie dans la banque de graines et à l’autorecrutement au sein des populations férales. La modélisation des flux efficaces de graines par une méthode de maximum de vraisemblance a permis d’identifier des dynamiques de dispersion locales au sein des agroécosystèmes. Suivant la zone considérée et les axes de circulation vers le silo de récolte, les sources locales de graines varient et les apports extérieurs de graines sont plus ou moins importants. Nos données nous ont permis d’estimer que les semis de la même année (n), les champs récoltés l’année antérieure ou même les années précédentes (jusqu’à n-2) pouvaient contribuer de manière significative à la présence de populations férales (l’année n). Les distances moyennes de dispersion estimées varient de la dizaine de mètres au kilomètre. Enfin, une expérimentation in-situ nous a permis de quantifier les pertes de graines pendant la récolte liées aux bennes de récolte. Nous avons évalué ces pertes à 400 graines par m2 et nous avons mis en évidence de rares évènements de pertes massives de graines. L’analyse statistique des résultats de ces pertes nous a permis de les mettre en relation avec des caractéristiques du paysage, notamment les surfaces des champs et les axes de circulations principaux et secondaires. Dans le contexte de mise en culture de plantes transgéniques, ces résultats impliquent de prendre en compte la complexité du paysage dans les modèles qui prédisent les flux de transgènes à l’échelle des agroécosystèmes. / Agroecosystems are mosaics of cultivated areas where natural and semi-natural areas and human infrastructures are strongly nested and intrinsically linked and dependent. Semi-natural areas are generally confined to field edges and roadsides where wild and cultivated plants biodiversity are combined. This thesis focuses mainly on seed dispersal of oilseed rape (Brassica napus L.) towards semi-natural areas which can lead to establishment of feral oilseed rape populations. At the agroecosystem scale, the study of genotypic data coupled with assignment methods to existing commercial cultivars has highlighted the link between diversity of cultivars of oilseed rape cultivated fields with diversity of cultivar of feral populations the following year. Furthermore, the study of cultivar diversity revealed that fields are not uniformly composed of plants of a unique cultivar and that feral populations accumulate different cultivars over years consecutive of annual seeds rain of harvested fields, survival in the seed bank and self-recruitment in feral populations. Modeling the effective seed flow with maximum likelihood method revealed local dispersal dynamics within the agroecosystem. Local and extern sources of seeds differ according the area studied and the traffic roads to the silo. Our data have shown that both sowing of the same year (n), the fields harvested the previous year or even in previous years (up to n-2) could significantly contribute to the presence of feral populations (year n). The average dispersal distances estimated range from ten meters to kilometers. Finally, an in-situ experiment enabled us to quantify seed losses during harvest related to grain trailers. We evaluated these losses to 400 seeds per m2 and we highlighted rare events of massive seed deposition. Statistical analysis of these losses enabled us to relate them with landscape elements, including the traffic roads and. In the context of GM crops cultivation in agroecosystems, these results emphasize the need to introduce the landscape complexity in models predicting the presence and persistence of GM OSR feral populations.

No description available.

Bonobos (Pan paniscus) are threatened with extinction. They are the largest primates, and the only apes (except human), of the southern bank of the Congo Basin. Along with chimpanzees, they are our closest living relatives and are studied by anthropologists to include/understand our hominid origins; but what about their functional role in the forest? Would their disappearance have serious consequences for forest ecology? Answering this question is the aim of this new project, with several years of observations of a free-ranging habituated group of bonobos on the LuiKotale research station (DR Congo). In this tropical rainforest, the very great majority of plants need animals to reproduce and disperse their seeds. Bonobos are the largest frugivorous animals in this region, after elephants. During its life, each bonobo will ingest and disperse nine tons of seeds, from more than 91 species of lianas, grass, trees and shrubs. These seeds will travel 24 hours in the bonobo digestive tract, which will transfer them over several kilometers (mean 1.3 km; max: 4.5 km), far from their parents, where they will be deposited intact in their feces. These dispersed seeds remain viable, germinate better and more quickly than unpassed seeds. For those seeds, diplochory with dung-beetles (Scarabaeidae) imrpoves post-dispersal survival. Certain plants such as Dialium may even be dependent on bonobos to activate the germination of their seeds, characterized by tegumentary dormancy. The first parameters of the effectiveness of seed dispersal by bonobos are present. Behavior of the bonobo could affect the population structure of plants whose seeds they disperse. The majority of these zoochorous plants cannot recruit without dispersal and the homogeneous spatial structure of the trees suggests a direct link with their dispersal agent. Few species could replace bonobos in terms of seed dispersal services, just as bonobos could not replace elephants. There is little functional redundancy between frugivorous mammals of the Congo, which face severe human hunting pressures and local exctinction. The defaunation of the forests, leading to the empty forest syndrome, is critical in conservation biology, as will be illustrated here. The disappearance of the bonobos, which disperse seeds of 65% of the tree species in these forests, or 11.6 million individual seeds during the life of each bonobo, will have consequences for the conservation of the Congo rainforest