The success or failure of many organisms to respond to the challenges of habitat destruction and a warming climate lies in the ability of plant species to disperse between isolated habitats or to migrate to new ranges. European semi-natural grasslands represent one of the world's most species-rich habitats at small scales, but agricultural intensification during the 20th century has meant that many plant species are left only on small fragments of former habitat. It is important that these plants can disperse, both for the maintenance of existing populations, and for the colonisation of target species to restored grasslands. This thesis investigates the ecological, geographical and historical influences on seed dispersal and connectivity in semi-natural grasslands, and the mobility of plants through time and space. Seed dispersal by human activity has played a large role in the build-up of plant communities in rural landscapes, but patterns have shifted. Livestock are the most traditional, and probably the most capable seed dispersal vector in the landscape, but other dispersal methods may also be effective. Motor vehicles disperse seeds with similar traits to those dispersed by livestock, while 39% of valuable grasslands in southern Sweden are connected by the road network. Humans are found to disperse around one-third of available grassland species, including several protected and red-listed species, indicating that humans may have been valuable seed dispersers in the past when rural populations were larger. Past activities can also affect seed mobility in time through the seed bank, as seeds of grassland plant species are shown to remain in the soil even after the grassland had been abandoned. Today however, low seed rain in intensively grazed semi-natural grasslands indicates that seed production may be a limiting factor in allowing seeds to be dispersed in space through the landscape. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Accepted. Paper 4: In press. Paper 5: Manuscript.</p>

The decline in range and density of many native New Zealand birds from mammalian predation has raised concerns over the functioning of ecosystem processes such as pollination and seed dispersal. At Maungatautari, almost all mammalian pests have been eradicated from within a pest-proof fence enclosing 3400 ha of native forest. I examined whether Maungatautari is restoring pollination and seed dispersal services to native plants, compared to a nearby non-treatment site, Pirongia Mountain. Five-minute bird counts made at Maungatautari and Pirongia (in 2002 and 2005 prior to pest eradication from Maungatautari, and in 2008 and 2010 following eradication) indicated that 10 of the 12 individual bird species examined showed significant changes in abundance following pest control. Six species showed an increase in abundance, including bellbirds (Anthornis melanura), tui (Prosthemadera novaeseelandiae) and kereru (Hemiphaga novaeseelandiae). Counts of all native species combined increased at Maungatautari while counts of all exotic species showed no trend over count years. In December 2010, 140 five-minute bird counts showed tui and bellbirds, key pollinators, to be more abundant at Maungatautari than Pirongia. Higher pollen loads on the stigmas of both female and hermaphrodite Fuchsia excorticata flowers at Maungatautari, compared to Pirongia, suggest that F. excorticata at Maungatautari received better pollination service. Fuchsia excorticata pollen loads collected from 67 sites around New Zealand indicate that female plants at sites with lower abundances of mammalian predators generally received better pollination service. Hermaphrodite F. excorticata plants had similar and high pollen scores in all regions, except for in the North Island. Five-minute bird counts in December 2010 also showed that kereru and blackbirds (Turdus merula), key seed dispersers along with tui and bellbirds, were more abundant at Maungatautari than Pirongia. A second measure of bird abundance, maximum counts, showed flock sizes of tui, bellbirds and kereru were larger at Maungatautari, but only significantly so for tui and bellbirds. Fuchsia excorticata fruits were removed more rapidly from plants at Maungatautari than at Pirongia (a 6-fold difference). There was twice the density of tawa fruits (bird cleaned and fleshy) under trees at Maungatautari compared to Pirongia, perhaps from reduced mammalian fruit predation. There was no significant site effect on tawa dispersal service (percent of fruit consumed by birds), but a significant site x fruit density interaction, suggests birds at Maungatautari provided better dispersal service to large fruit crops. A similar number of miro fruit (bird cleaned and fleshy) were caught in seed traps under miro trees, but a greater percentage of fruits were consumed by birds at Maungatautari (59%) compared to Pirongia (26%). The results from this thesis indicate that increased densities of key native birds at Maungatautari are providing better pollination and dispersal services to the native plants examined. Projects which increase the density of key bird mutualists, such as tui, bellbirds and kereru, on the mainland, may have positive benefits for pollination and seed dispersal mutualisms.

Widespread anthropogenic invasions have prompted concerns that naturalized organisms could threaten biodiversity. In particular, invasive weeds can negatively affect native biota through a variety of means, including disrupting mutualisms. This thesis was designed to observe and test dispersal mutualisms in a native forest during autumn when the majority of plant species are fruiting. In this thesis I examined whether the invasive plant barberry (Berberis glaucocarpa) was influencing the behaviour of a native frugivore bellbird (Anthornis melanura) and a range of dispersal related services in a native forest, Kowhai Bush near Kaikoura. To test these 18 banded bellbirds were followed through autumn 2011. These observe bellbirds were split between control and test bird. Barberry fruit was removed from the test bird territories. I recorded whether bellbirds changed their territory sizes, foraging and daily behaviours. During 52 hours of observations, bellbirds were never observed feeding on barberry fruit. No significant changes to bellbird behaviour or territories were observed after the removal of barberry fruit. Bellbird diet overall was dominated by invertebrates (83% of foraging observations), with smaller contributions from fruit (16%, nearly all on Coprosma robusta), nectar and honeydew. Since bellbirds did not eat barberry fruit, removal of this weed is unlikely to negatively affect bellbirds during autumn. Which other bird species were dispersing barberry was recorded. I recorded 242 hours of videotape footage on 24 fruiting plants. A total of 101 foraging events were recorded of 4 different bird species: silvereyes (Zosterops lateralis) 42 visits, blackbirds (Turdus merula) 27 visits, song thrush (Turdus philomelos) 29, and starlings (Sturnus vulgaris) 3 visits. The species differed in the mean length of time they spent in plants, so the overall contribution to barberry fruit removal was 32.6% silvereyes, 24.3% blackbirds, 42.9% song thrush and 0.1% starlings. To find out the relative contribution of exotic and native birds to dispersal of fruits in Kowhai Bush, I mist-netted 221 birds of 10 species and identified any seeds in the 183 faeces they deposited. A total of 21 plant species were observed fruiting in Kowhai Bush during this time. A total of 11 different plant species were identified from 1092 seeds. Birds were further observed feeding on 3 other plant species which were not observed in faecal samples. This left 7 plants with unobserved dispersal vectors. There were likely four main dispersers, bellbirds, silvereyes, song thrush and blackbirds and five minor, brown creeper (Mohoua novaeseelandiae), tui (Prosthemadera novaeseelandiae), fantails (Rhipidura fuliginosa), dunnock (Prunella modularis) and starlings. However there was considerable variability between these bird species dispersal abilities. Introduced birds’ song thrush and blackbirds were observed dispersing naturalized plant seeds at higher than expected rates in comparison to native frugivores bellbirds and silvereyes. I also measured the gape sizes on mist netted birds and on samples of fruit from Kowhai Bush. Both silvereyes and bellbirds were found to be eating fruit larger than their gape, but despite this two native (Hedycarya arborea and Ripogonum scandens) and three exotic plants (Vitis vinifera, Taxus baccata and Crataegus monogyna) had large fruit that were probably mainly dispersed by song thrush and blackbirds. Hence, introduced birds were important seed dispersers for large fleshy fruited seeds in Kowhai Bush. Demonstrating that interactions among native and exotic flesh fruited plants and frugivores is important within forest communities.

Mistletoes are a group of hemiparasitic plants that grow on a wide variety of host trees and differ in their degree of host specificity, ranging from specialists to generalists. Mistletoes can also be locally host specific where host preference varies geographically, i.e. at a given location a mistletoe species may infect only part of its overall host set. The mistletoe Agelanthus natalitius parasitises at least 11 tree genera distributed throughout South Africa. However, there is geographic variation in infection patterns over the parasite’s range, suggesting that A. natalitius may be locally host specific. We quantified the degree of host specificity and tested the mechanisms that direct host specialisation in two distinct mistletoe populations at Highover and Mtontwane (about 110 km apart) in KwaZulu-Natal, South Africa. We investigated the distribution, abundance and community composition of woody species that host the mistletoe. We also assessed the effect of light on germination and early survival of the mistletoes in a greenhouse experiment. We conducted field reciprocal transplant experiments at both sites to investigate the compatibility of these mistletoes with their hosts Acacia karroo and A. caffra during early development. We then analysed the nutrient and water contents of the mistletoe-host pairs to investigate the role of nutrient and water status in directing host specificity in mistletoes. We further studied avian dispersal in the field and in captivity to investigate optimal dispersal distance and germination success, and evaluated their role in determining mistletoe host specificity. At both study sites, five host species were recorded as being parasitised by the mistletoe A. natalitius. A. karroo and A. caffra appear to be the two most common host species in the region; both grow abundantly at the study sites and were recorded with high infection by A. natalitius. However, A. karroo is the most abundant host species and the mistletoe showed a high degree of host specificity on A. karroo. Infection by mistletoes was positively correlated with tree size, and was highly aggregated, both individually and locally. Field observations and greenhouse shade experiments showed that light can influence mistletoe distribution. Germination of mistletoe seeds was independent of host species and site. However, hypocotyls (the structures that develop into haustoria) grew longer when placed on their source host species within their locality. Additionally, they showed preference for the most abundant host species, A. karroo. Water and nutrient status of the host species A. karroo and A. caffra had no significant effect. Thus, host nutrient and water content may not account for host specificity in this mistletoe species. Mistletoes accumulated more nutrients and maintained more negative than their host trees. We also investigated the mistletoes’ use of passive nutrient uptake (from host xylem) and active nutrient uptake (from host phloem) by using the N:Ca ratio as an index of nutrient access. Mistletoes growing on A. caffra had a ratio > 1, i.e. the mistletoe actively accessed nutrients from the phloem of host trees. However, mistletoes on A. karroo had a N:Ca ratio < 1, which implies that they passively accessed nutrients from the xylem. The difference in mechanism of nutrient acquisition on different host species may reflect the level of compatibility between mistletoe and host. Several bird species were frequently observed to feed on mistletoes, many of which were used in our captivity studies. Although birds did not consume mistletoe fruits in captivity as they do in the field, they were effective in removing the pulp cover of mistletoe fruits and exposing seeds in germinable condition. In captivity, the Red-winged Starling ingested whole fruits and regurgitated seeds, deliberately wiping their bills on twigs to remove the sticky seeds. As a result, germination success of mistletoes processed by Red-winged Starlings was higher than any other bird species tested in captivity. Overall, there appears to be host specificity in morphologically identical mistletoes. Understanding the mechanisms that result in host race evolution are potentially important to the process of speciation in hemiparasitic mistletoes. We need to take into account genotypic matching in conserving these different forms of mistletoes and their host Acacia genotypes. Further research into the mechanisms of host specificity and patterns of genotypic matching is warranted. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

La formiga invasora Linepithema humile (Mayr), també coneguda com la formiga argentina, és una espècie present a la península Ibèrica. En aquesta tesi s'ha estudiat com afecta la presència d'aquesta espècie plaga a la comunitat de formigues autòctones y al procés de dispersió de llavors de plantes mediterrànies. L'estudi es va dur a terme en una àrea de sureda i brolla d'estepes i bruc boal situada al nord-est peninsular, prop de la línia de costa mediterrània. Un dels primers y més notables efectes de la invasió a les nostres àrees d'estudi és la dramàtica alteració de la comunitat de formigues, en forma de una reducció de la riquesa específica i de la homogeneïtat d'abundàncies. A més, a les zones envaïdes no hi queda cap espècie de formiga autòctona dispersant de llavors. A causa de la gran abundància d'obreres de la formiga argentina a les zones envaïdes, i del seu elevat ritme d'activitat, aquesta espècie efectua un intens rastreig del sòl, la qual cosa li permet localitzar els recursos en un temps menor que les formigues autòctones de les zones no envaïdes. No obstant, la obertura mandibular de la comunitat de formigues esdevé molt disminuïda a les zones envaïdes a causa de la desaparició de les espècies autòctones, la majoria d'elles de mida més grossa que la formiga argentina, la qual cosa podria limitar la capacitat de manipulació de l'entorn que té la comunitat de formigues a les zones envaïdes, i podria explicar la falta de reemplaçament d'alguns dels rols que duien a terme les espècies de formigues autòctones abans de la invasió.La formiga argentina es mostra atreta per les llavors de les nou espècies vegetals estudiades (dues euforbiàcies: Euphorbia biumbellata i E. characias; dues compostes: Cirsium vulgare i Galactites tomentosa; i cinc papilionàcies: Genista linifolia, G. monspessulana, G. triflora, Sarothamnus arboreus i Ulex parviflorus), arribant a transportar i fins i tot introduir al niu algunes llavors, però amb probabilitats inferiors a les realitzades per les formigues autòctones de les zones no envaïdes. No obstant, el seu comportament davant les nou espècies de llavors és variable, de manera que sembla que el seu efecte sobre la dispersió de llavors podria ser diferent per a cada espècie vegetal. L'alteració del procés de dispersió no sembla alterar l'èxit reproductiu d'una espècie concreta, Euphorbia characias, a les zones envaïdes; ni el seu reclutament, ni la distribució espacial, ni la supervivència de les plàntules són significativament diferents a les zones envaïdes que a les no envaïdes. La desaparició de les espècies de formigues granívores de les zones envaïdes pot afectar la dinàmica de les llavors de plantes no mirmecòcores. Així, les llavors de tres papilionàcies (Calicotome spinosa, Psoralea bituminosa i Spartium junceum) resulten amb un menor nivell de transports (i probablement menor depredació) a les zones envaïdes per la formiga argentina. / The invasive ant Linepithema humile (Mayr), known as the Argentine ant, is present in the Iberian peninsula. This thesis is focused on the effect of the presence of this pest ant over the native ant community and the seed dispersal process of Mediterranean plants. The study was carried out in a cork oak secondary forest situated in the north-eastern Iberian peninsula, near the Mediterranean coast.One of the first and most notorious effects of the invasion in our study areas is the dramatic alteration of the ant community, with a reduction of the ant species richness and the homogeneity of abundances. Moreover, any native seed dispersal ant remains at the invaded zones. Due to the higher abundance of Argentine ant workers in the invaded areas, and their higher "tempo" of activity, this species carries out an intense soil surface searching and can find resources in a lower time than native ants do in the non-invaded zones. However, the mandible gap of the ant community becomes highly reduced in the invaded zones due to the displacement of the native ant species, most of them bigger than the Argentine ant. This could limit the ability of ants in handling the environment in the invaded zones, and could explain the lack of replacement of some tasks carried out by the native ants before the invasion.The Argentine ant is attracted by the seeds of the nine studied plant species (two euforbiaceae: Euphorbia biumbellata and E. characias; two compositae: Cirsium vulgare and Galactites tomentosa; and five papilionaceae: Genista linifolia, G. monspessulana, G. triflora, Sarothamnus arboreus and Ulex parviflorus), transporting and even introducing some seeds to the nest, but with lower probabilities than the native ants in the non-invaded zones. However, its behavior in front of the nine seed species is variable, so the effect over the seed dispersal process could be different for each plant species. The alteration of the seed dispersal process appears not to affect the reproductive success of a single species, Euphorbia characias, in the invaded zones; neither recruitment, spatial distribution, nor survival of seedlings are significantly different between the invaded and the non-invaded zones. The disappearance of the native granivorous ant species from the invaded zones can affect the seed dynamics of non-myrmecochorous species. In this sense, seeds of three papilionaceae (Calicotome spinosa, Psoralea bituminosa and Spartium junceum) result with a lower level of transport (and probably lower predation) in zones invaded by the Argentine ant.

Thesis (Ph. D.)--Miami University, Dept. of Botany, 2006. / Title from second page of PDF document. Includes bibliographical references.

Orientador: Mauro Galetti / Banca: Leonor Patrícia Cerdeira Morellato / Banca: Wesley Rodrigues da Silva / Resumo: O presente estudo compreende duas partes. A primeira, descreve o comportamento fenológico do palmito Euterpe edulis, e correlaciona com os fatores ambientais: temperatura e precipitação. A segunda, determina a comunidade de aves que utiliza os frutos do palmito e correlaciona a abundância das mesmas com o número de palmitos frutificando. O estudo foi desenvolvido em três formações florestais contíguas: Floresta de Restinga (nível do mar), Floresta Pluvial Tropical de Planície Litorânea (05-30 metros acima do nível do mar) e Floresta Pluvial Tropical de Encosta (200-250 m acima do nível do mar) no Parque Estadual da Ilha do Cardoso, Cananéia, São Paulo. Para avaliação da fenologia de frutificação foram acompanhados 150 indivíduos adultos de palmito, 50 indivíduos para cada tipo florestal, durante agosto/2001 a agosto/2002. A floração do palmito na Ilha do Cardoso foi anual e sazonal, com duração de seis meses. Quanto aos três tipos florestais, houve variações quanto ao número de palmitos em floração, sincronia e pico de atividade. A produção de frutos maduros na Ilha do Cardoso iniciou-se no mês de fevereiro, com a maior porcentagem dos indivíduos manifestando a fenofase no mês de abril (44,49%). Quanto aos três tipos florestais, a floresta de restinga mostrou um pico de atividade discreto, apresentando apenas 16% dos indivíduos com frutos maduros no mês de março, a floresta de planície com 82% dos indivíduos no mês de abril e a floresta de encosta com 52% dos indivíduos no mês de maio. Sobre a frugivoria, foram registradas 18 espécies de aves que consumiram os frutos do palmiteiro através de 188 horas de árvore-focal e 136 horas de transectos lineares nos três tipos florestais. O registro das aves frugívoras iniciou-se nos meses em que os frutos verdes e maduros estavam disponíveis (abril-junho/01 e fevereiro-junho/02)...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present study is divided in two parts. First, it describes the phenological behavior of the palm Euterpe edulis and correlates with environmental variables: temperature and rainfall. Second, it determines bird communities that feed on the palm's fruits and correlates its abundance with number of palms with fruits available. The study was developed in three continuous forest formations: Restinga forest (sea level), Lowland forest (05-30 m above sea level), highland forest (200-250 m above sea level) at Ilha do Cardoso State Park, Cananéia, SP. To evaluate the fruit production phenology, 150 palms were studied, 50 palms at each forest type, from August/01 to August/02. The palm-heart's flowering was annual and seasonal, during 6 months, with peaks occurring at months with higher temperatures and precipitation. In relation to the three forest types, variations occurred in the number of flowering individuals, synchrony and activity's peak. Fruit production started on February, with highest percentage of individuals at the fenofase occurring on April (44,49%). Restinga forest did have a discreet peak, with only 16% of its individuals with ripe fruits in March; in the lowlands with 82% individuals in April and in the highlands with 52% in May. Eighteen bird species were recorded feeding on palm fruits (188 hours of focal observations and 136 hours of linear-transect on the three forest types). The frugivore birds were recorded when ripe and unripe fruits were available (April-June/01 and February-June/02). In the Restinga Forest, the Muscicapidae family was responsible for 53% (n = 8) from all visits; in the lowland forest this family was responsible for 55,6% (n = 59) and in the highland forest for 51,3% (n = 38). The bird species that showed a positive significative correlation of abundance (IPA) with number of fruiting palms were: Turdus albicollis (rs=0,880; p=0,020)...(Complete abstract click electronic access below) / Mestre

Nas florestas sazonalmente inundadas de terras baixas da Amazônia, os peixes frugívoros desempenham diferentes serviços ecossistêmicos: possuem um papel importante na dispersão de sementes (regulação), além de serem um recurso (provisão) para pescadores artesanais. O uso extensivo de recursos limitados pode gerar conflitos de interesse entre os objetivos conservacionistas e as necessidades dos habitantes locais. O co-manejo tenta integrar a segurança alimentar e a conservação dos ecossistemas na forma de reservas extrativistas (RESEX), onde os habitantes locais podem retirar recursos florestais seguindo regras de manejo. Neste trabalho testamos a influência do co-manejo sobre os peixes frugívoros do rio Tapajós (águas claras) e Negro (águas pretas) na Amazônia brasileira. Foram testadas as seguintes hipóteses: 1)Peixes frugívoros são importantes para os pescadores e são seletivamente escolhidos pela pesca; 2) A abundância, tamanho e a produtividade pesqueira dos peixes frugívoros são maior dentro da RESEX. Durante quatro meses, pescadores locais registraram 1.457 desembarques pesqueiros em oito comunidades em cada rio. Além disso, foram amostrados 12.730 peixes em 208 pontos de malhadeira em 32 sitios em lagos e no canal do rio nas comunidades estudadas. Peixes frugívoros estão entre as dez espécies mais pescadas nos dois rios, indicando a sua importância para as comunidades locais. Nos dois rios a porcentagem de peixes frugívoros era maior no registro dos desembarques pesqueiros (22% de 7.342 kg no rio Tapajós e 14% of 4.609 kg no rio Negro) que vii nas amostragens científicas (5,9% de 349,2 kg no rio Tapajós e 6% of 458,3 kg no rio Negro), indicando uma seletividade dos pescadores para os frugívoros. / In seasonally flooded forests of lowland Amazonia, frugivorous fish provide different ecosystem services (ESS): They play an important role in seed dispersal (regulating ESS), but they are also an essential resource for artisanal fisheries (provisioning ESS). Extensive use of limited resources can generate conflicts of interest between conservation goals and the needs of local livelihoods. Co-management schemes try to integrate local food security and ecosystem conservation in the form of extractive reserves (RESEX), where inhabitants are exclusively allowed to extract forest resources while following management rules. Here, we assess the influence of co-management on frugivorous fish and local fisheries of Tapajos (clear water) and Negro (black water) River in the Brazilian Amazon. To this end, we test the following hypotheses: 1) Frugivorous fish are important for fisheries and selectively extracted; 2) Frugivorous fish abundance, size and fisheries productivity is higher inside the RESEX than outside. Fish landings from 1457 fishing trips were registered over four months by local fishermen in eight fishing communities of each river. Further, 12,730 fish were sampled through 208 gillnet placements, in 32 sites in the floodplain lakes and river channels of the communities. Frugivorous fish are among the ten most fished species in both rivers, reflecting their importance for local communities. In both rivers, landing records show a higher percentage of frugivorous fish biomass (22% of 7,342 kg in Tapajós and 14% of 4,609 kg in Negro River) than samplings (5.9% of 349.2 kg in Tapajós and 6% of 458.3 kg in Negro River), indicating a selectivity of fisheries towards frugivores. A pressão pesqueira (medida como demanda por pescado) nos frugívoros se mostrou mais elevada fora de cada RESEX (8 ± 5,4 kg no Rio Tapajós e 5,6 ± 3,1 kg no Rio Negro) que dentro (0,7 ± 0,3 kg no Rio Tapajós e 0,8 ± 0,1 kg no rio Negro). A produtividade da pesca, medida em Captura por Unidade de Esforço (CPUE), e a proporção de peixes frugívoros na captura total foram maiores fora da RESEX no rio Tapajós (CPUE: t=-3,7; dF = 4,2; p = 0,02; proporçao: t = -6,7; dF = 5; p = 0,001) e não variaram no rio Negro (CPUE: t = -1,9; dF = 5,6; p = 0,1; proporçao: t = -0,9; dF = 4,6; p = 0,4). No geral, o tamanho dos peixes frugívoros foi maior dentro da RESEX no rio Negro, mas não no rio Tapajós. Os pescadores capturaram pacus de maior tamanho (Myleus spp., Mylossoma spp., Myloplus spp., Metynnis spp.) dentro da RESEX no rio Negro (D=0,42; p<0,001). No rio Tapajós não foi possível detectar efeitos da RESEX nos parâmetros medidos para os peixes frugívoros. A reserva do rio Negro parece favorecer o tamanho e a disponibilidade de peixes frugívoros, apesar de eles serem selecionados pela pesca local. Apesar de uma pressão pesqueira possivelmente elevada, peixes frugívoros foram abundantes dentro e fora da RESEX em ambos os rios, possivelmente devido a demandas do mercado, efeitos de spillover ou baixa conformidade às regras de de manejo dentro da RESEX. Contudo, os frugívoros parecem estar cumprindo seu papel de recurso alimentar e de dispersores de sementes. Nosso estudo evidencia que o monitoramento participativo baseado na comunidade é uma ferramenta economicamente eficiente para a caracterização da pesca local. No entanto, para se atingir os objetivos de conservação e assegurar o recurso alimentar, é necessário que haja um controle do acesso de pessoas de fora das áreas de conservação e um reforço do cumprimento das regras de manejo. Portanto, continua sendo possível manter os dois serviços ecossistêmicos fornecidos por esses peixes nos rios de águas claras e negras estudadas na Amazônia brasileira.

The rock outcrop plants are neglected group of plants, even though they include endangered or endemic species. Despite this fact, there is only a few of studies focusing at this topic. The aim of this thesis is to focus on this group of plants in terms of its population dynamics. Aurinia saxatilis ssp. saxatilis was chosen as a model species. It is a species of the Czech thermophyticum. Three populations were chosen and studied over three years. The population dynamics was compared between the populations by integral projection modelling (IPM) and matrix population modelling (MPM). The results of these two analytical approaches were compared to one another, too. The population growth rate (λ) predicts that one of the populations is stable, whereas the other two populations are declining. The highest elasticity is mostly for the seeds survival in the seed bank. The population growth rate does not differ distinctly between the two statistical approaches, IPM and MPM. In all cases the IPM λ is lower than the MPM λ. Within the IPM analysis, the influence of the substrate type was also studied. The analyses, however, did not indicate any major differences between the substrates. For maintaining the populations, it is necessary to protect the new seeds and seedling recruitment and to create the new space...

Les bonobos (Pan paniscus) sont menacés d’extinction. Ils sont les plus grands primates et les seuls grands singes de la rive sud du bassin du Congo. Ils sont nos plus proches parents avec les chimpanzés et sont étudiés dans l’urgence par les anthropologues pour comprendre nos origines Hominidé. Mais qu’en est-il de leur rôle fonctionnel dans la forêt ? Leur disparition aurait-elle des conséquences graves sur l’écologie forestière ? Telles sont les questions de ce projet inédit, dont les réponses sont apportées par plusieurs années d’observations d’un groupe en liberté habitué au site de recherche LuiKotale (RD Congo). Dans cette forêt tropicale humide, la très grande majorité des plantes a besoin des animaux pour se reproduire et disperser leurs graines. Les bonobos sont les plus grands frugivores après les éléphants. Au cours de sa vie, chaque bonobo ingèrera et dispersera 9 tonnes de graines, de plus de 91 espèces de lianes, herbes, arbres et arbustes. Ces graines voyageront 24 heures dans le tube digestif des bonobos, qui les transporteront sur plusieurs kilomètres (≈1.3km; max : 4.5 km), loin de leur plante mère, où ils seront déposées intactes dans leurs fèces. Ces graines dispersées restent viables, germent mieux et plus rapidement que les graines non passées par le tube digestif d’un bonobo. La diplochorie, impliquant les bousiers (Scarabaeidae), favorise leur survie post dispersion. Certaines plantes comme les Dialium pourraient même être dépendants du bonobo pour activer la germination de leurs graines en dormance tégumentaire. Les premiers paramètres de l’efficacité des bonobos comme disperseurs de graines sont présents. Leurs comportements pourraient affecter la structure des populations végétales. La majorité de ces plantes zoochores ne peuvent recruter sans dispersion et la structure spatiale homogène des arbres laisse penser à un lien direct avec leur agent de dispersion. Peu d’espèces remplaceraient les bonobos en terme de leur rôle fonctionnel, tout comme les bonobos ne remplacent pas les éléphants. Il y a peu de redondance fonctionnelle entre les mammifères frugivores très différents du Congo, qui doivent faire face aux pressions de chasse des hommes et disparaissent localement. La défaunation des forêts, résultant dans le syndrome des forêts vides, est un problème grave de biologie de la conservation illustré ici. La disparition des bonobos qui dispersent les graines de 65% des arbres de leur forêt, ou encore 11.6 millions de graines au cours de la vie d’un bonobo, est liée à la conservation des forêts tropicales humides du Congo / 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