Esta tese foi concebida para se integrar ao eixo nº 5 (Paleoclimas e Paleoambientes no final do Peistoceno e Holoceno na região de Lagoa Santa) da terceira versão do projeto temático Origens e Microevolução do Homem na América: uma abordagem paleoantropológica (FAPESP proc. 04/01321-6), onde a principal questão abordada é a existência de um grande período (de 8.000 a 2.000 anos A.P) de drástica redução de sepultamentos e vestígios arqueológicos na região de Lagoa Santa, MG. Para esse período, as pesquisas palinológicas no Brasil central e sudeste, embora existam em número razoável, possuem interpretações paleoambientais contraditórias. Bem caracterizado no Hemisfério Norte, ao redor de 6000 anos A.P., o evento climático conhecido como Ótimo Climático, período predominantemente mais quente e úmido, se estabeleceu devido a uma maior insolação terrestre, propiciando a expansão de coberturas vegetais de maior porte e umidade de diversos pontos do globo e é sustentado por diversos autores para muitas localidades brasileiras. Por outro lado, embora não existam dúvidas de que o nível do mar esteve acima do atual na costa brasileira, é consenso que alterações climáticas foram mais amenas e aparentemente mais complexas. Amparados por este raciocínio, outros estudos sugerem eventos de seca no período aproximado de 6000 a 4500 anos A.P. Neste contexto, objetivando verificar a provável diferença climática ocorrida durante o Holoceno médio é confirmada pelo estudo de lenhos fósseis de região e sustenta a hipótese de a redução de sepultamentos da região reflete um deslocamento humano por causas climáticas, utilizaram-se duas abordagens diferentes no estudo anatômico de lenhos fósseis datados do Holoceno médio e tardio: uma abordagem florística, feita através da identificação taxonômica das amostras fósseis e comparação com localidades atuais; e através de uma abordagem anatômico-ecológica do lenho de Myroxylon peruiferum L.f., que utilizou correlações existentes entre o clima e as características anatômicas pra predizer o clima pretérito da região com base nas características anatômicas dos fósseis. Para a primeira abordagem, foram também realizados um levantamento florístico-lenhoso da APA Carste de Lagoa Santa e estudos fitossociológicos nas diferentes fitofisionomias da região, que proveram informações adicionais para as interpretações paleoambientais. Como resultado, os estudos florísticos e fitossociológicos, além de grande valia para a interpretação das assembléias fósseis, mostraram uma riqueza expressiva de espécies na região. A identificação das assembléias fósseis do Holoceno médio e tardio mostrou muita similaridade entre as duas assembléias, sugerindo a ausência de mudanças climáticas significativas a ponto de alterar a florística da região. Ainda, essas assembléias fósseis são relacionadas fortemente com o mosaico de vegetações existentes na região, que aponta para a manutenção desta vegetação desde o Holoceno médio. Por outro lado, a abordagem anatômico-ecológica revelou uma maior sazonalidade climática durante o Holoceno médio. Embora pareçam conflitantes, estes resultados são interpretados como complementares, e indicam um período sensivelmente mais sazonal no Holoceno médio, porém insuficientes para propiciar alterações florísticas no mosaico vegetacional que existia na época e caracteriza hoje a região. Esses resultados, portanto, não apóiam a hipótese de alterações intensas no clima, na flora e nem na presença das vegetações que ali existiam desde 5.000 anos A.P. / This thesis is designed to integrate the shaft Nº. 5 (Paleoclimates and paleoenvironments in the Late Pleistocene and Holocene at Lagoa Santa region) of the third version of the Project Origins and Microevolution of man in América: an approach paleoanthropological (FAPESP proc. 04/01321-6), where the main issue addressed is the existence of a large period (8000-2000 years BP) of drastic reduction of burials and archaeological sites in Lagoa Santa, MG. For that period, palynological research in central and southeastern Brazil, althoug in reasonable numbers, have contradictory paleoenvironmental interpretations. Well characterized in the Northern Hemisphere, around 6000 yeras BP, the climatic event known as Climatic Optimum, predominantly warmer and wetter, was established due to greater solar insolation, favoring the expansion of humid vegetation cover various parts of the globe and is supported by several authors for many places in Brazil. Moreover, although there is no doubt that the sea level was above the current along the Brazilian coast, there is consensus that climate change was milder and seemingly more complex. In the same way, other studies suggest drought events in the approximate period 6000 to 4500 years B.P. In this context, to verify if the climatic differences likely ocurred during the middle Holocene is confirmed by the study of fóssil Wood from the region and supports the hypothesis that the reduction of burials in the region reflects a human migration causes climate, we used two different approaches in a anatomical study of fóssil Wood dated to the middle and late Holocene: 1.) a floristic approach, made through the taxonomic identification of fóssil specimens and comparison with current local florist, and 2.) through na approach of ecological Wood anatomy of Myroxylon peruiferum L.f., which correlation between climate and anatomical characteristics were used to predict the past climate of the region based on the same anatomical characteristics in fossils samples. For the first approach, were also carried out a floristica-woody survey of APA-Lagoa Santa Karst and phytosociological studies in different Forest types in the region, which provided additional information for paleoenvironmental interpretations. As a result, floristic and phytosociological studies, besides showing great importance for the interpretation of fóssil assemblages, revealed and expressives richness of species. The identification of fóssil assemblages from middle and late Holocene showed high similarity between both, suggesting the absence of enough climate change lo alter the flora in the region. Still, these fóssil assemblages are strongly related with the mosaico of vegetation in the region, pointin to the maintenance of vegetation since the middle Holocene. Furthermore, the ecological-anatomy approach revealed a greater climatic seasonality during the middle Holocene. Although these two approaches seem conflicting, these results are interpreted as complementary, and show a markedly more seasonal period in middle Holocene, but insufficient to provide floristic changes in the vegetation mosaic that existed nowadays and characterizes the region. These results therefore do not support the hypothesis of intense changes in climate, flora and even in the presence of vegetation that existed there since 5000 years BP.

Magister Artium (Development Studies) - MA(DVS) / It is well established that the modern global food system is highly unsustainable, distorted by industrialisation and corporate consolidation, with negative repercussions on the environment and biodiversity as well as human health. Innovative approaches are necessary to push food systems to be more sustainable, equitable, and healthy for all people regardless of income and wealth. In the Cape Town area, the food system is failing to adequately nourish the poor, while climate change poses increasing challenges to the region’s agricultural system. Conceptualising food systems as complex adaptive social ecological systems and utilising the Multilevel Perspective (MLP) framework, this thesis looks at the burgeoning economy in neglected and underutilised species (NUS) in the Cape Town area as a potential innovation that could make the local food system more socially and ecologically resilient. Though at present NUS are only marginally included in the local food system and policy debates, they are increasingly appearing in the food service industry, driven by international gastronomic trends. They hold potential as climate resilient, nutritionally dense, and socially and culturally significant foods in the region, but also carry ecological and social risks. This thesis critically examines the fledgling NUS economy in the Cape Town area, using participant observation and semistructured interviews to unpack its primary motivations and challenges, and ultimately contributes towards a better understanding of the NUS economy as it develops locally. This research shows that the main risks associated with NUS are negative ecological repercussions, privatisation of the NUS economy, and the reproduction and further entrenchment of unequal power dynamics in the region. In order to mitigate these risks and actualise the related benefits associated with NUS, engagement with the ecological, social, and political context of NUS needs to be significantly deepened. This is particularly true for those working in food service, who appear to be driving the NUS economy, and will require education around sustainability and TEK as well as a foregrounding of power-awareness.

No description available.

As part of a vegetation survey program for the newly acquired farms incorporated into the Loskop Dam Nature Reserve, the vegetation of the Hondekraal Section was investigated. The study provides an ecological basis for establishing an efficient wildlife management plan for the Reserve. From a TWINSPAN classification, refined by Braun-Blanquet procedures, 12 plant communities, which can be grouped into eight major plant communities, were identified. A classification and description of the major plant communities are presented as well as a management plan. Descriptions of the plant communities include characteristic species as well as prominent and less conspicuous species of the tree, shrub, herb and grass strata. This study proves that the extended land incorporated into the Reserve contributes to the biological diversity of the Reserve. / Environmental Sciences / M. Tech. (Nature Conservation)

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Only a limited number of systems involving anther-smut fungi have been studied, usually due to the economic significance of their crop plant hosts. A smut fungus of the genus Thecaphora has been discovered infecting Oxalis hosts in South Africa. This pathogenic fungus, Thecaphora capensis, produces dark-coloured spores in the anthers of host flowers, rendering it an anther-smut fungus. The host genus is the seventh largest plant genus in the Cape Floristic Region (CFR) and the largest geophytic genus of this region. Nine Oxalis species that host T. capensis have been identified across a wide distribution in the CFR of South Africa. A preliminary assessment of T. capensis infections of Oxalis was conducted in 2009, which provided a foundation for further research into the ecological and evolutionary consequences of hosting this fungus. In this study, a comprehensive host diversity assessment was conducted to determine the extent of infected Oxalis individuals within the CFR. Three new Oxalis host species for Thecaphora capensis were discovered. This brings the total number of known hosts to twelve. The morphological and reproductive effects of the fungus were assessed on two host species (O. incarnata and O. lanata) by comparing healthy and infected individuals of these species. Infection by Thecaphora capensis had a significantly negative effect on both of these factors. Host resources appear to be co-opted for fungal spore production, since floral morphological characters of infected individuals were reduced in size. Furthermore, infection by T. capensis ensured near-universal sterility in both hosts. Differences in floral characters and pollinator preferences for healthy Oxalis incarnata and O. lanata individuals from disease-free and diseased populations were compared to determine the evolutionary influence of Thecaphora capensis infections. It was shown that this pathogen can have a significant evolutionary influence on its hosts, showing its ability to shape flower size and pollinator activity in O. lanata, but not in O. incarnata. A need has therefore been identified to assess these evolutionary forces independently for each host and its pathogen before making erroneous assumptions for conservation practices. Plant pollinators play an integral role in plant fitness. Pollinator movements within a population are important when between-flower spore transfer by pollinators increases the likelihood of new infections. Pollinator movements may be influenced by host density and the frequency of diseased individuals, amongst other factors. Pollinators were found to mediate Thecaphora capensis spore transfers within diseased Oxalis populations. Host density and disease frequency affected the number of spores transferred under field and standardized conditions. More research is required to investigate confounding factors in these complex systems. This study highlighted the complexities of a fungal-plant-insect relationship, the evolutionary consequences of such fungal infections and the various factors influencing the likelihood of new infections. This research adds to the limited body of knowledge on multi-organismal interactions in the CFR and provides a base for more detailed future studies on this intriguing system. / AFRIKAANSE OPSOMMING: 'n Brandswam, wat deel is van die Thecaphora genus,is ontdek in 'n Oxalis blom waar dit die gasheer plant se blom gebruik om spore in te produseer. Die swam, Thecaphora capensis, produseer donker gekleurde spore in die helmknoppe van die blomme van gasheer plante, daarom word dit geklasifiseer as 'n brandswam van die helmknop. Die gasheer plante van die swam is deel van die genus Oxalis, die sewende grootste plant genus in die Kaapse Floristiese Streek (KFS) en die grootste geofitiese genus in die streek. Nege Oxalis species is al klaar identifiseer as gasheer plante van T. capensis. Hulle is versprei oor 'n groot area van die KFS van Suid Afrika. 'n Primêre ondersoek van T. capensis infeksies op Oxalis is in 2009 onderneem. Hierdie ondersoek het gelei tot meer vrae oor die sisteem en het 'n goeie fondasie geskep vir verdere navorsing rakende die ekologiese koste verbonde daaraan om as gasheer plant vir 'n swam op te tree. 'n Deeglike ondersoek is in die KFS aangepak om die Oxalis gasheer plante van die brand swam te identifiseer en om voort te bou op die basiskennis wat in die primêre ondersoek daargestel is. Drie nuwe Oxalis gasheer plante van Thecaphora capensis is ontdek. Die totale aantal gasheer plante staan nou op twaalf. Gesonde en geinfekteerde individuele gasheer plante is gebruik om die morfologiese en reproduktiewe effekte van die swam te toets in twee Oxalis spesies (O. incarnata en O. lanata). Die negatiewe gevolge om 'n gasheer plant van die brand swam te wees was duidelik toe gesonde en geinfekteerde individuele met mekaar vergelyk is. Dit kom voor asof gasheer plante se hulpbronne vir spoor produksie gebruik word, want hulle is morfologies kleiner en meestal steriel. Die evolusionêre effek van Thecaphora capensis op 'n populasie is getoets met gesonde individuele in populasies van twee Oxalis spesies. Blomkenmerke en insek bestuiwers van gesonde individue in gesonde en geinfekteerde populasies is ondersoek om die effekte van T. capensis op populasies te toets. Daar is suksesvol gedemonstreer dat swamme sterk evolusionêre kragte uitoefen, en die vermoë het om plantpopulasies te vorm en te verander, ofskoon nie in alle gevalle ewe sterk nie. Daarom is dit belangrik om die evolusionêre kragte vir elke gasheer plant en sy patogeen onafhanklik te assesseer, sonder om algemene aannames te maak in bewaringspraktyke. Plantbestuiwers speel 'n belangrike rol in die fiksheid van plante. Hulle kan hul fiksheid verbeter deur bestuiwers te lok met blomme en deur aspekte geassosieer met blomme. Die bewegingspatrone van plantbestuiwers is baie belangrik indien hulle helmknop-geproduseerde spore van brandswamme vervoer instede van stuifmeel, want dit vergroot die kanse vir nuwe infeksies. Die bewegingspatrone van plantbestuiwers word, onder andere, beinvloed deur die digtheid en frekwensie van geinfekteerde individue. Plantbestuiwers speel 'n belangrike rol in die vervoer van Thecaphora capensis spore in geinfekteerde Oxalis populasies. Die digtheid en frekwensie van geinfekteerde blomme het die vervoer van spore geaffekteer onder veld en gestandardiseerde kondisies, alhoewel baie veranderlikes so 'n komplekse natuurlike sisteem beinvloed. Hierdie studie beklemtoon die kompleksiteit van 'n fungus-plant-insek verhouding, die gevolge van so 'n interaksie en die verskeie faktore wat die waarskynlikheid van nuwe infeksies beinvloed. Tot dusver is daar 'n beperkte aantal sisteme soos hierdie bestudeer waarin 'n brandswam van die helmknop betrokke is, en die enkele beskikbare studies is onderneem meestal as gevolg van hulle ekonomiese effekte op landboukundig belangrike gasheer plante. Hierdie studie verteenwoordig 'n belangrike byvoeging tot die inter-organismiese studies in die KFS. 'n Holistiese ekologiese oorsig soos hierdie verskaf 'n belangrike basis vir toekomstige studies en bewarings- en bestuurspraktyke.

Thesis (PhD (Zoology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The Cape Floristic Region (CFR) is a biodiversity hotspot in South Africa, threatened by climate change and various other processes. The Greater Cederberg Biodiversity Corridor (GCBC) is a conservation area incorporating both public and private land, providing a practical and effective solution to conserve biodiversity in the CFR. This area is also home to two of the eight melanistic cordylid lizard species found in south-western South Africa. One of the herpetological conservation targets identified for the GCBC was an understanding of the ecology of melanistic cordylid populations with particular reference to global environmental change. Most melanistic cordylids occur in cool coastal and montane localities, and it was suggested that melanism has a thermoregulatory function in these species. The first aim of this study was to determine the climatic conditions with which melanistic cordylids are currently associated. Several melanistic cordylid populations showed a distinct association with a high incidence of fog and cloud cover, underscoring the thermal melanism hypothesis, which predicts that melanistic lizards should occur in cool environments. Several other populations, however, did not show such an association. The next aim was thus to compare habitat use and morphology among 10 melanistic cordylid populations. Individuals of the northern population of Pseudocordylus capensis and the Cordylus peersi population occurred in the warmest environments, used significantly higher rock formations, and had relatively longer limbs than those of other melanistic populations. Having a morphology that allows for flexibility in habitat use, may enable species such as P. capensis to overcome the constraints of melanism in warm environments. Being melanistic may result in decreased activity times in warm environments. The variation in habitat thermal quality and daily activity patterns of two melanistic cordylid species with different morphologies and habitat preferences, occurring sympatrically, was investigated. During summer, high rocks provided a better thermal quality habitat to P. capensis than small rocks, and P. capensis had a longer activity period than C. oelofseni. This suggests that the thermal opportunities provided by high rock enables P. capensis to increase its activity time. The impact of terrestrial and aerial predators can help shape body armour in lizards, with those species more exposed to aerial predators being faster and less armoured, and those more exposed to terrestrial predators being more heavily armoured. The degree of body armour in melanistic cordylids and their non-melanistic relatives was investigated. Melanistic members of the cordylus-niger-oelofseni and C. polyzonus clades had less armour than their non-melanistic relatives, supporting the prediction that melanistic cordylids basked more and were more exposed to aerial predators than non-melanistic lizards. An increase in body armour in C. peersi indicated exposure to terrestrial predators, whereas P. capensis had a reduction in body armour, indicating exposure to aerial predators. Little body armour, together with a slender morphology and long limbs, may thus enable this species to move with ease on large boulders and scale vertical surfaces to successfully avoid predators. Pseudocordylus capensis displayed much greater movement rates during activity than other cordylids. A less sedentary foraging strategy may be a prerequisite for life on large, barren rock surfaces where food availability may be low or not uniformly distributed. Both males and females of this species also had large home ranges, a unique phenomenon for cordylids. Space use of males only overlapped marginally, but extensive overlap among males and females and among females, respectively, was observed. Due to the constraining effect of climate on the distribution of most melanistic populations, melanistic cordylids should be considered as priority species for conservation. While P. capensis is pre-adapted for survival in warm climates, it is dependent on the availability of suitable habitats. The GCBC would thus play an important role in the conservation of this species’ habitat. / AFRIKAANSE OPSOMMING: Die Kaapse Blommeryk (KBR) is ‘n “biodiversity hotspot” in Suid-Afrika wat deur klimaatsverandering en verskeie ander prosesse bedreig word. Die Groter Cederberg Biodiversiteitskorridor (GCBK) is ’n bewaringsarea wat beide openbare en privaatgrond inkorporeer, en ’n praktiese en effektiewe oplossing tot die bewaring van biodiversiteit in die KBR bied. Twee van die ag melanistiese gordelakkedisse wat in suidwestelike Suid-Afrika aangetref word, kom ook hier voor. Een van die herpetologiese bewaringsdoelwitte vir die GCBK was om insig oor die ekologie van melanistiese gordelakkedis populasies met verwysing na globale omgewingsveranderinge in te win. Die meeste melanistiese gordelakkedisse kom in koel kus- en berggebiede voor, en daar is voorgestel dat melanisme ‘n termoregulerende funksie by hierdie spesies het. Die eerste doel van die studie was om die huidige klimaatstoestande waarmee melanistiese gordelakkedisse geassosieer word, te bepaal. Verskeie melanistiese gordelakkedis-populasies het ‘n duidelike assosiasie met mis en wolkdekking getoon, wat die termiese melanisme hipotese se voorspelling dat melanistiese akkedisse in koue omgewings moet voorkom, ondersteun. Verskeie ander populasies, het egter nie so ‘n assosiasie getoon nie. Die volgende doel was om habitatgebruik en morfologie tussen 10 melanistiese gordelakkedispopulasies vergelyk. Individue van die noordelike populasie van Pseudocordylus capensis en Cordylus peersi het in die warmste omgewings voorgekom, het relatief langer ledemate gehad en beduidend hoër rotsformasies as ander melanistiese populasies benut. ’n Morfologie wat buigsame gebruik van die habitat toelaat, kan sommige spesies soos P. capensis in staat stel om die beperkinge van melanisme in ‘n warm omgewing te oorkom. In warm omgewings mag melanisme tot ’n afname in aktiwiteitstye lei. Variasie in termiese kwaliteit van die habitat en daaglikse aktiwiteitspatrone van twee melanistiese spesies, met verskillende morfologieë en habitatvoorkeure, wat simpatries voorkom is bestudeer. Gedurende somer het hoë rotse ‘n beter termiese kwaliteit habitat aan P. capensis verskaf as die klein rotse, en P. capensis het ‘n langer aktiwiteitsperiode as C. oelofseni gehad. Dit stel voor dat die termiese geleenthede wat deur hoë rotse verskaf word, P. capensis in staat stel om sy aktiwiteitsperiode te verleng. Die invloed van terrestriële en lugpredatore kan help om liggaamspantser in akkedisse te vorm. Spesies wat hoofsaaklik aan lugpredatore blootgestel is, is vinniger en het minder pantser, terwyl spesies wat hoofsaaklik aan terrestriële predatore blootgestel is, meer pantser het. Die graad van pantser in melanistiese gordelakkedisse en hulle nie-melanistiese naasverwantes is ondersoek. Melanistiese lede van die cordylus-niger-oelofseni en C. polyzonus klades het minder pantser as hulle nie-melanisties naasverwantes gehad, en ondersteun die voorspelling dat melanistiese gordelakkedisse meer in die son gebak het en meer aan lupredatore blootgestel was. ’n Toename in pantser by C. peersi dui op blootstelling aan terrestriële predatore, terwyl P. capensis die minste pantser van alle melanistiese gordelakkedisse het, wat dui op blootstelling aan lugpredatore. Min beskerming, tesame met ‘n lenige morfologie en lang ledemate, mag dus hierdie spesie toelaat om gemaklik oor groot rotse en vertikale oppervlaktes te beweeg en roofdiere suksesvol te vermy. Pseudocordylus capensis het groter bewegingstempo’s tydens aktiwiteit as ander gordelakkedisse getoon. ‘n Meer beweeglike voedingstrategie mag ook ‘n voorvereiste wees vir ‘n lewe op groot, leë klipoppervlaktes waar voedselbeskikbaarheid dalk laag kan wees en nie eweredig versprei is nie. Beide mannetjies en wyfies het ook groot tuisgebiede gehad, ’n unieke verskynsel by gordelakkedisse. Mannetjies se ruimtes het slegs marginaal oorvleuel, terwyl daar heelwat oorvleueling tussen mannetjies en wyfies se ruimtes was. As gevolg van die beperkende invloed van klimaat op die verspreiding van die meeste melanistiese populasies, moet melanistiese gordelakkedisse as prioriteitspesies vir bewaring beskou word. Terwyl P. capensis pre-aangepas is vir oorlewing in warm klimate, is hierdie spesie afhanklik van die beskikbaarheid van gepaste habitatte. Die GCBK sal dus ’n belangrike rol vervul in die bewaring van die habitat van hierdie spesie.

La conservation des mares temporaires implique la connaissance, à la fois de leur fonctionnement et de leurs dynamiques temporelles, à court et long terme. La thèse, réalisée sur une mare temporaire du plateau gréso-quartzitique de Benslimane, s'organise en trois volets. (1) Le premier concerne la relation entre le pollen de surface et la végétation hydrophytique locale, dans le but d'établir un référentiel actuel pour l'étude paléoécologique de la mare. Les résultats obtenus montrent que la zonation de la végétation de la mare est correctement reconstruite à partir des enregistrements polliniques. Trois taxons clés (Isoetes velata-type, Myriophyllum alterniflorum, Ranunculus-type) peuvent être utilisés pour reconstituer la structure végétale passée. (2) Le second volet concerne l'histoire de la mare, en associant les données de la littérature et les données paléoécologiques obtenues à partir d'un sondage. Les résultats permettent de dater l'origine de la mare entre 1 million et 700 000 ans avant aujourd'hui. Ils témoignent de la conservation de la topographie régionale, par bilan sédimentaire négatif, jusqu'à environ 5000 cal. BP. A cette époque, le changement du fonctionnement morphogénétique de la mare, probablement lié au développement des pratiques agro-pastorales, a entraîné le comblement progressif de la mare. L'intensification des activités humaines constitue à moyen terme la principale menace concernant les mares du plateau de Benslimane, et par voie de conséquence, sur la préservation du plateau lui-même, que les mares protègent de l'érosion. (3) Le dernier volet apporte enfin un éclairage sur les processus mis en jeu dans la régénération de la végétation après micro-perturbations. Les résultats montrent une restauration rapide des microsites perturbés par dispersion proximale et effet de bordure. Toutefois, la dynamique de recolonisation reste liée aux conditions hydrologiques locales / Conservation of temporary pools implies the knowledge, about both their functioning and their temporal dynamics, on the short and the long term. The thesis, dealing with a temporary pool of the limestone-quartzite Benslimane plateau, is organised in three sections. (1) The first one concerns the relationship between the surface pollen and the hydrophytic vegetation, in order to establish a modern reference for the paleoecological study of the pool. The results show that the vegetation zonation is correctly reconstructed from the pollen records. Three key taxa (Isoetes velata-type, Myriophyllum alterniflorum, Ranunculus-type) may be used for reconstructing the past vegetation structure. (2) The second section deals with the pool history, by combining data from literature and palaeoecological data obtained from a sediment profile. Results allow dating the origin of the pool between 1 million and 700,000 years before today. They attest the conserv ation of the regional topography, by negative sedimentary balance, until ca. 5000 cal. BP. Then, the change of morphogenetic functioning of the pool, probably related to the development of agro-pastoral practices, resulted in the progressive filling of the pool. In the medium term, the intensification of human activities constitutes the main threat concerning the Benslimane pools, and consequently, on the conservation of the whole plateau, protected from erosion by pools. (3) The last section finally highlights the processes implied in the regeneration of the vegetation after micro-disturbances. The results show a fast restoration of the disturbed microsites by proximal dispersal and border effect. However, the recolonisation dynamics remains dependent on local hydrological conditions.

Les activités humaines ont, depuis plus d'une centaine d'années, influencé de plus en plus fortement les cycles géochimiques contrôlant les niveaux d'acidité et de disponibilité en azote dans la nature. Les dépôts acides et azotés conduisent à une modification des conditions du milieu et notamment à des changements sensibles de la composition des communautés d'espèces végétales. L'objectif de cette thèse est de retracer l'évolution spatio-temporelle de l'acidité et de la disponibilité en azote des sols forestiers français au cours du 20ème siècle à partir du caractère bio-indicateur de la flore, à l'échelle locale ainsi globale. L'utilisation de la flore comme bio-indicateur vise à pallier l'absence de données de mesures directes des conditions édaphiques et des dépôts atmosphériques acides et azotés couvrant une large emprise spatio-temporelle. Premièrement, les variations de pH (indicateur d'acidité) et C:N (indicateur de disponibilité en azote) bio-indiquées ont été calculées à partir d'environ 100 000 relevés floristiques temporaires réalisés dans toute la France de 1910 à 2010. Elles ont été analysées par une méthode novatrice de comparaison spatio-temporelle, en différenciant les zones forestières sur substrat acide et non-acide ainsi que les forêts de conifères et de feuillus. Dans un second temps, nous avons analysé les changements des conditions édaphiques entre 1972 et 2011 à l'échelle de la forêt de Villey-Le-Sec, et ceux de la flore qu'ils induisent en lien avec d'autres évolutions environnementales, toujours à partir du caractère bio-indicateur de la flore.À l'échelle globale, nous avons observé une acidification des forêts françaises en milieu acide (-0.34 unités du pH en moyenne) et milieu non-acide (-0.19 unités du pH en moyenne), respectivement, jusqu'en 1984 et 1997. Nous avons ensuite mis en évidence, pour la première fois à notre connaissance, un arrêt dans l'acidification des sols forestiers et même une diminution de l'acidité sur substrat non-acide ainsi que un décalage temporel entre l'acidification des zones acides et non-acides. Cette évolution apparaît tout à fait cohérente avec celle connue des dépôts atmosphériques acidifiants en France depuis le début du 20ème siècle. Spatialement, nous confirmons la tendance temporelle, montrons une évolution régionalisée de l'acidification principalement sur substrat non-acide et soulignons la grande variabilité spatiale des changements de pH des sols forestiers. Concernant l'évolution de la disponibilité en azote, nous observons une diminution non attendue de celle-ci jusqu'en 1984 et 1997, respectivement, dans les forêts de conifères (+0.79 unités de C:N en moyenne) et de feuillus (+0.74 unités de C:N en moyenne). Une tendance à l'eutrophisation des sols forestiers a ensuite été observée dans les forêts de conifères et de feuillus à partir de 1997 (-0.10 et -0.16 unités de C:N en moyenne, respectivement). Cette évolution apparaît décalée par rapport à celle des dépôts azotés en France. [...] Suite et fin du résumé dans la thèse. / Human activities have, over the last century, strongly influenced the cycles controlling the levels of acidity and nitrogen availability in nature. Acidifying and eutrophying deposition lead to a change in environmental conditions and particularly to sensitive changes in plant communities' composition.The objective of this Ph.D work is to reconstruct the spatiotemporal evolution of the acidity and nitrogen availability in French forest soils over the 20th century using the bioindicator character of plants, into local and global scales. The use of plants as bioindicator seeks to mitigate the lack of direct measurements of soil conditions and atmospheric deposition, over a wide spatiotemporal extent. First, changes in bioindicated soil pH (indicator of acidity conditions) and C:N (indicator of nitrogen availability status) were computed from approximately 100 000 temporary floristic plots carried out throughout France from 1910 to 2010. They were analyzed using an innovative method of spatiotemporal comparison, where acidic and nonacidic forest areas and coniferous and broadleaved forests were differentiated. Secondly, and always from the bioindicator character of plants, changes in soil conditions between 1972 and 2011 across Villey forest as well as floristic changes they induce related with other environmental changes were analyzed.At the global level, we observed acidification in acidic forest areas (-0.34 pH units on average) and in nonacidic areas (-0.19 pH units on average), respectively, until 1984 and 1997. We demonstrated for the first time (to our knowledge) a cessation of acidification of forest soils and even a decrease in acidity in nonacidic forest areas, as wella as a time lag for acidification between acidic and nonacidic areas. This trend is consistent with the trend of acidifying deposition in France since the early 20th century. Spatially, our results confirm the temporal trends, show a regional geographic pattern of acidification (mainly observed in nonacidic areas), and highlight the high spatial variability of soil pH changes. Concerning the evolution of nitrogen availability conditions, we observed an unexpected decrease in available nitrogen until 1984 and 1997, respectively, in coniferous (+0.79 C:N units on average) and broadleaved forests (+0.74 C:N units on average). A trend to eutrophisation of forest soils was then observed in coniferous and broadleaved forests since 1997 (-0.10 and -0.16 C:N units on average, respectively). This trend is not consistent with the trend of nitrogen atmospheric deposition in France. ”Last and final summary in the thesis.”

No contexto da conservação biológica, a fragmentação florestal é definida como uma separação ou desligamento não natural de áreas amplas em fragmentos espacialmente segregados, promovendo a redução dos tipos de habitats e a divisão dos habitats remanescentes em unidades menores e isoladas. A magnitude e a extensão dessas alterações na paisagem são influenciadas pelo tamanho, conectividade, forma, contexto e heterogeneidade dos fragmentos. Visando a conservação ambiental do município de Paulínia-SP, este trabalho teve como objetivo efetuar o diagnóstico da vegetação remanescente. Os fragmentos florestais identificados no município foram: Floresta Estacional Semidecidual, Floresta Estacional Semidecidual Ribeirinha, Floresta Paludosa e Cerrado. A caracterização da vegetação foi realizada através do levantamento florístico rápido baseado no tempo de amostragem. Os 104 fragmentos apresentaram riqueza de 517 espécies, sendo 447 espécies nativas regionais (região de Paulínia), 18 espécies nativas não regionais (nativas de outras regiões do Brasil) e 52 exóticas (originárias de outros países). Foram registradas espécies raras como Tabebuia insignis, Pilocarpus pennatifolius, Salix humboldtiana, Handroanthus umbellatus. A análise de similaridade florísica utilizando-se o Método de agrupamento de Sorensen foi efetiva para separar os fragmentos de Cerrado e Floresta Paludosa e mostrou tendência de agrupamento para algumas variações fisionômicas da Floresta Estacional Semidecidual. Com a finalidade de se obter dados quantitativos (abundância) das espécies, foram registradas todas as espécies diferentes encontradas em cada intervalo de tempo de amostragem no Levantamento Rápido. Obtiveram-se indicativos das 517 espécies com relação a serem raras ou comuns na paisagem, em cada formação florestal e em cada fragmento estudado. Foi aplicado um total de 801 intervalos de tempo de 15 min de amostragem e gerados 21.324 registros. A composição de espécies variou com o tamanho e grau de conservação dos fragmentos. Foram analisadas as influências do tipo de fisionomia florestal, tamanho e estado de conservação dos fragmentos na composição das espécies em relação às classes de sucessão ecológica e às síndromes de dispersão. A composição das classes de sucessão variou com o tamanho e estado de conservação dos remanescentes de Floresta Estacional Semidecidual e Floresta Estacional Semidecidual Ribeirinha. Em fragmentos menores e muito degradados houve predominância de espécies em estágios iniciais de sucessão (pioneiras e secundárias) em relação à classe de final de sucessão (clímax). Houve predominância da zoocoria, seguida de anemocoria e depois autocoria em todas as situações analisadas. / In biological conservation, forest fragmentation is defined as a separation or nonnatural disconnection of wide areas in spatially segregated fragments, generating a reduction of habitat types and the split of remnant habitat in smaller isolated units. The magnitude and extension of these landscape alterations are influenced by size, connectivity, shape, context and heterogeneity of fragments. Aiming environmental conservation of the municipality of Paulinia, SP, this study aimed to diagnose the remnant vegetation. The forest fragments identified in the municipality were: Seasonal Semidecidual Forest, Seasonal Semidecidual Riparian Forest, Swamp Forest and Savanna. The vegetation characterization was done through a quick floristic search based on sampling time. The 104 fragments presented a richness of 517 species, 447 of which are regional native species (Paulinia region) and 18 are non-regional native species (from other regions of Brazil); and 52 exotic species (from other countries). These fragments presented rare species as Tabebuia insignis, Pilocarpus pennatifolius, Salix humboldtiana, Handroanthus umbellatus. The floristic similarity analysis using the Sorensen method was particularly effective to separate Savanna and Swamp Forest fragments and showed a tendency for grouping some variations of Seasonal Semidecidual Forest. In order to obtain quantitative data (abundance) about the species, all different species found in each time interval in the quick floristic search were recorded. Indicatives for 517 species were obtained classifying then into rare or common in the landscape, in each forest formation, and in each fragment studied. 21.324 records were generated for a total of 801 intervals of 15 minutes sampling. Species composition varied with size and conservation degree of fragments. The influences of the forest physiognomy type, size and conservation status of fragments on species composition related to ecological succession classes and dispersion syndromes were analyzed. The ecological classes composition varied along with the size and conservation status for the fragments of Seasonal Semidecidual Forest and Seasonal Semidecidual Riparian Forest. In smaller and very degraded fragments there was a predominance of species from initial sucessional stages (pioneer and secondary species) in comparison to species from final stages of succession (climax). There was predominance of zoochory, followed by anemochory and autochory in all situations analyzed.

O presente trabalho visou compreender os padrões florísticos e fitogeográficos de Campo Sujo Seco na bacia hidrográfica do ribeirão Taquaruçu Grande, no município de Palmas (TO). A análise de sua paisagem baseou-se na produção de mapas de vegetação; localização e medição da área de distribuição; caracterização fitossociológica e florística, buscando identificar padrões de Campo Sujo Seco; e, verificação da influência dos solos e do relevo na formação de tais padrões. O trabalho foi realizado em etapas de laboratório e campo. O mapeamento foi feito com base na carta da Diretoria do Serviço Geográfico (DSG) do Ministério do Exercito e IBGE de 1979 e imagens LANDSAT de 2011. Utilizou-se o software SPRING 5.1.8 (INPE). A caracterização pedológica foi feita por meio de delineamento em blocos casualizados, com aplicação do teste T e análise de variância com comparação das médias pelo teste de Tukey, usando o software Bio Estat 5.0. A caracterização da vegetação foi feita pelo método de parcelas e os parâmetros biométricos medidos foram diâmetro a altura do solo e altura de arbustos e árvores. Os parâmetros fitossociológicos analisados foram densidade, frequência, dominância absolutas e relativas e valor de importância específica. Foram calculados índices de similaridade de Sørensen, de diversidade de Shannon-Wiener e de uniformidade de Pielou. A análise de agrupamento entre áreas foi feita pela classificação UPGMA, pelo índice de Jaccard e e ordenação por Análise em Componentes Principais, utilizando-se o software Fitopac 2, e pelo método Twinspan, com o software WinTWIN. A paisagem da bacia do ribeirão Taquaruçu Grande é composta pelos geofácies Mata de Galeria, Mata Ciliar, Mata Seca, Cerradão, Cerrado Sentido Restrito, Babaçual, Vereda, Campo Sujo Seco, Campo Limpo Úmido, Campo Rupestre, Lago, ribeirões, córregos e brejos, Área Urbana e Agropecuária/Silvicultura. O Campo Sujo Seco teve uma área de 7.478,82 ha (16,2% da bacia hidrográfica), localiza-se nos planaltos e chapadas da serra do Lageado e nas planícies secas da depressão do Tocantins. Os solos são do tipo Plintossolos Pétricos e se caracterizaram como bem drenados e com baixo teor de água, ácidos, distróficos, álicos com altos teores de ferro e de textura média. A flora pertence à divisão Magnoliophyta (angiospermas) é, predominantemente, da classe Magnoliopsida, com 39 famílias, 82 gêneros e 121 espécies. A densidade total foi de 2.761,47 indivíduos.ha-1; a dominância de 5,64 m2. ha-1; o diâmetro média de 4,61 cm e a altura média de 1,12 m. Existe alta similaridade florística entre topo e encosta (0,79) e alta diversidade alfa (3,533 nats.indivíduo-1). De acordo com a densidade de plantas, há padrões de campos sujos secos densos, típicos e ralos em relevos de topos e encostas. Pelos métodos de agrupamento UPGMA, Coordenadas Principais e Twinspan, há padrões florísicos representados, principalmente, pelas espécies Vochysia cinnamomea, Byrsonima subterranea e Vellozia seubertina. Os campos de V. cinnamomea localizam-se no sul da bacia, os de B. subterranea no norte e os de V. seubertiana no centro-norte, que constituíram os geótopos do geofácie Campo Sujo Seco. Existem padrões estruturais, florísticos e fitogeográficos diversos de campo sujo seco na bacia hidrográfica do ribeirão Taquaruçu Grande e as condições ambientais de relevo e edáficas tiveram influência na formação desses padrões. / The present work aimed to understand the patterns floristic and phytogeographical countryside of campo sujo in River watershed Taquaruçu Grande, municipality of Palmas (TO). The analysis of the landscape was based on the production of vegetation maps, location and measurement range; floristic and phytosociological characterization, seeking to identify patterns of Campo Sujo Seco; and check the influence of soils and relief in the formation of such patterns. The work was carried out in steps of laboratory and field. The mapping was done based on the letter from the Board of Geographic Service (DSG) of the Brazilian Army (EB) and IBGE 1979 and digital images were used LANDSAT 2011. The software used was the SPRING 5.1.8 (INPE). The pedological characterization was made by means of a randomized block design, with application of the \"t\" test and analysis of variance for comparison of means by Tukey\'s test, using the software Bio Stat 5.0. The vegetation characterization was done by the method of plots and biophysical parameters measured were diameter at ground height and height of shrubs and trees. The phytosociological parameters analyzed were density, frequency, dominance of absolute and relative amount of specific importance. Sørensens similarity indices were calculated, as well as the Shannon-Wiener Diversity Index and the Equitability of Pielou. Cluster analysis between areas was done by UPGMA classification, the Jaccard index and ranking by Principal Component Analysis, using the software Fitopac 2, and the method Twinspan with software WinTWIN. The landscape of the basin of the Taquaruçu Grande comprises the geofacies Gallery Forests, Riparian Forests, Dry Forests, Cerradão, Cerrado Sensu Stricto, Babaçual, Veredas, Campo Sujo Seco, Campo Limpo Úmido, Campo Rupestre, lake, creeks, streams and swamps, Urban area and Agricultural area. The Campo Sujo Seco with patches of cerrado sensu stricto had an area of 7.478,82 ha (16,2% of the watershed), located in the highlands and plateaus of the Serra do Lageado and the dry plains of depression Tocantins. Soils are the type Petric Plinthosols and were charactrized as well-drained, low water content, acidic, dystrophic, alic with high levels of iron and medium textured. The flora belongs to the division Magnoliophyta (angiosperms) is predominately class Magnoliopsida, with 39 families, 82 genera and 121 species. The total density was 2761.47 individuals.ha-1, the dominance of 5.64 m2. ha-1, the mean diameter of 4.61 cm and height of 1.12 m. There is high floristic similarity between top and slope (0.79) and high alpha diversity (3,533 nats.individual-1). According to the density of plants, there are patterns of Campo Sujo Seco dense and sparse typical reliefs on the tops and slopes. By cluster UPGMA, Principal Coordinates and Twinspan, there are florisics patterns represented mainly by species Vochysia cinnamomea, Byrsonima subterranea and Vellozia seubertina. The V. Cinnamomea fields located in the southern basin, the B. subterranean in the north and those of V. seubertiana in north-central, which constituted the geotopes the geofacie Campo Seco Seco. There are structural patterns, floristic and phytogeographical various Campo Sujo Seco in River watershed Taquaruçu Grande and environmental conditions of relevant and soil influenced the formation of these patterns.