Factors relating to natural regeneration and tree community recovery after slash and burn agricultural practices were investigated in secondary seasonally dry tropical forests (SDTF) of varying land use intensity and post-disturbance management. Patterns and processes of regeneration were explored by collecting community composition data at secondary and primary sites, by conducting seedling experiments, and by investigating existing forest rehabilitation efforts in both Lao PDR (Laos) and Vietnam. In the forests surveyed in Laos, forest recovery in terms of the composition of primary forest tree species juveniles in fallow forests was high at most sites regardless of previous land use intensity. While community compositional studies indicated significant differences between primary and secondary communities, little or no significant differences were found in terms of primary tree species or family diversity, evenness, or dominance of regenerating juveniles. Significant differences appeared to be due to changes in the relative abundances of different species rather than the absence of primary forest obligate species in the secondary communities. This effect is expected to be due to the relatively common resprouting ability of SDTF species, the wide range of ecological conditions that these species can persist under, and the mosaic pattern of land-uses across the landscape. Evidence of environmental filtering affecting composition patterns in secondary communities was found for two plant traits; dispersal syndrome and plasticity of specific leaf area (SLA). Ecological strategies of primary SDTF tree species were investigated in two ways. Within the narrow range of species capable of regenerating within the primary forest environment, evidence of different life history strategies was found, indicated by significant correlations between continuous plant traits of seed size, fruit size, maximum tree height, SLA, leaf size and wood density. The correlations found largely mirrored patterns found in similar studies in Neotropical forests. Evidence of different seedling regeneration strategies was investigated by comparing species of two different successional preference groups in a seedling/light experiment. Seedlings of non-pioneer later successional species responded differently than species more associated with disturbed environments (long-lived pioneers) when exposed to both increasing absolute light treatments, and to light received under various sunfleck treatments. Earlier successional species demonstrated greater plasticity of SLA, leaf area ratio (LAR), stem elongation, and root mass ratio to increasing light. Regeneration under minimally managed monoculture and pair-wise plantations of both native and exotic species at the Laos field site was not significantly different when compared with nearby remnant primary forest in terms of diversity, evenness, and richness. Therefore, plantation overstoreys did not appear to be suppressing the regeneration of primary forest species. Seedlings grown in enrichment designs nearby had survival rates of approximately 50%, and diameter increments of less than 0.2 cm/yr after 6 to 9 years of growth. The performance of seedlings in such plantings is expected to be sufficient for conservation aims but is unlikely to encourage private investment for forestry purposes due to long expected rotation lengths. At Hai Van Pass in central Vietnam, the combination of a fast growing exotic species to capture a degraded site and ameliorate site conditions, followed by enrichment planting of native species was demonstrated to be a successful approach to reforesting degraded land, whilst funding itself through the sale of timber. The results indicate the high regeneration potential of the studied secondary forests, both in terms of observed patterns of regeneration in slash and burn fallow forests, and in terms of the general regenerative abilities of SDTF species. Decisions regarding future land-uses and secondary forest management should have consideration of this possible high level of recovery, and simple diversity sampling techniques should be included in any related processes to confirm the regeneration potential of a particular secondary forest.

At present there is uncertainty over the response of neotropical ecosystems to the climatic changes of the Quaternary. The majority of vegetation reconstructions from the region are derived from fossil pollen records extracted from lake sediments. However, the interpretation of these records is restricted by limited knowledge of the contemporary relationships between the vegetation and pollen rain of neotropical ecosystems, especially for more open vegetation such as savanna and dry forest. This research aims to improve the interpretation of these records by investigating the relationship between the vegetation and modern pollen rain of different savanna and seasonally dry tropical forest (SDTF) ecosystems in Bolivia using artificial pollen traps and surface lake sediments to analyse the modern pollen rain. Vegetation data is used to identify taxa that are floristically important within the different ecosystems and to allow modern pollen/vegetation ratios to be calculated. The modern pollen rain from the upland savanna is dominated by Moraceae/Urticaceae (35.1%), Poaceae (29.6%), Alchornea (6.1%) and Cecropia (4.1%), whilst the seasonally-inundated savanna sites are dominated by Moraceae/Urticaceae (30.7%), Poaceae (19.5%), Cyperaceae (14.0%) and Cecropia (7.9%). These two different savanna ecosystems are only slightly differentiated by their modern pollen rain. The main taxa in the modern pollen rain of the upland SDTF are Moraceae/Urticaceae (25.8%), Cecropia (10.5%), Acalypha (7.6%) and Combretaceae/Melastomataceae (6.7%). Seasonally-inundated SDTF is dominated by Cecropia pollen to the extent that it was removed from the pollen sum and the main non-Cecropia pollen types are Moraceae/Urticaceae (39.0%), unknown type df 61 (6.4%), Asteraceae (6.3%), Celtis (6.0%) and Physocalymma scaberrimum (4.9%). These two SDTF ecosystems are well differentiated by their modern pollen rain, implying that they may be defined in fossil pollen records. The modern pollen rain obtained from the surface lake samples is generally complementary to that obtained from the artificial pollen traps for a given ecosystem. All sites have a high Moraceae/Urticaceae pollen signal due to effective dispersal of this pollen type from areas of evergreen forest in close proximity to the study sites. The savanna sites show lower Poaceae percentages than have been previously reported in the literature by some authors and this raises the possibility than the extent of this ecosystem in the past may have been underestimated. Modern pollen/vegetation ratios show that many key vegetation types are absent/under-represented within the modern pollen rain.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-06-02T22:53:26Z No. of bitstreams: 1 ArthurDeSouzaSoares_DISSERT.pdf: 3203622 bytes, checksum: 8b7b33ba2abe93cb3c9b8ba7ca489c8b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-06-09T22:02:26Z (GMT) No. of bitstreams: 1 ArthurDeSouzaSoares_DISSERT.pdf: 3203622 bytes, checksum: 8b7b33ba2abe93cb3c9b8ba7ca489c8b (MD5) / Made available in DSpace on 2017-06-09T22:02:26Z (GMT). No. of bitstreams: 1 ArthurDeSouzaSoares_DISSERT.pdf: 3203622 bytes, checksum: 8b7b33ba2abe93cb3c9b8ba7ca489c8b (MD5) Previous issue date: 2017-03-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Lamiaceae, 236 g?neros e cerca de 7.200 esp?cies distribu?das em sete subfam?lias, possui distribui??o cosmopolita, com a maioria de suas esp?cies ocorrendo na regi?o tropical do planeta. Para o Brasil s?o listadas 524 esp?cies em 46 g?neros, dentre as quais, seis g?neros e 343 esp?cies s?o end?micos. No estado do Rio Grande do Norte (RN), est?o catalogados oito g?neros e 13 esp?cies, onde apenas um g?nero e quatro esp?cies s?o end?micos do Brasil. Esta disserta??o est? dividida em dois cap?tulos, os quais s?o apresentados aqui como manuscritos independentes j? nos padr?es exigidos pelas revistas escolhidas para publica??o, cujas normas est?o anexadas a esta disserta??o. Os cap?tulos s?o: Lamiaceae no Rio Grande do Norte, Brasil, onde ? apresentado o tratamento taxon?mico e flor?stico da fam?lia Lamiaceae no estado do Rio Grande do Norte. Neste estudo foram registradas 30 esp?cies, das quais 14 s?o ex?ticas, naturalizadas ou cultivadas e 16 constituem as esp?cies nativas. As esp?cies Hyptis brevipes Poit. e Vitex rufescens A.Juss. ocorrem apenas no dom?nio Mata Atl?ntica, enquanto Amasonia campestris (Aubl.) Moldenke, Eriope macrostachya Mart. ex Benth., Gymneia platanifolia (Benth.) Harley & J.F.B.Pastore, Mesosphaerum pectinatum (L.) Kuntze, Hyptis lantanifolia Poir., Mesosphaerum sp., Vitex gardneriana Schauer, Vitex schaueriana Moldenke, ocorrem apenas no dom?nio Caatinga. As esp?cies Mesosphaerum suaveolens (L.) Kuntze e Marsypianthes chamaedrys (Vahl.) Kuntze foram as que apresentaram a maior distribui??o dentro do territ?rio do estado. No segundo cap?tulo, New records, conservation assessments and distribution of Lamiaceae in Rio Grande do Norte, northeastern, Brazil, ? apresentado o Status de conserva??o das esp?cies de Lamiaceae e sua distribui??o no RN incluindo as esp?cies e g?neros citados pela primeira vez para o estado. Entre as esp?cies nativas, tr?s foram classificadas como ?Amea?adas?, quatro como ?Vulner?veis?, tr?s s?o de ?Pouco Preocupante?, duas s?o ?Quase Amea?adas? e quatro s?o ?Dados Insuficientes?. O dom?nio fitogeogr?fico Caatinga, uma Floresta Tropical Sazonalmente Seca (SDTF), tem o maior n?mero de esp?cies de Lamiaceae, embora menos de 1% desta regi?o seja protegida por unidades de conserva??o. Este estudo revela o estado preocupante da conserva??o da fam?lia Lamiaceae na RN e a necessidade de a??es de conserva??o, como a cria??o de novas unidades de conserva??o para preservar a qualidade do habitat e as forma??es naturais remanescentes e monitorar popula??es na natureza. / Lamiaceae, 236 genera and about 7,200 species distributed in seven subfamilies, has cosmopolitan distribution, with most of its species occurring in the tropical region of the planet. For Brazil, 524 species are listed in 46 genera, of which six genera and 343 species are endemic. In the state of Rio Grande do Norte (RN), they are cataloged of genera and 13 species, where only one genus and four species are endemic to Brazil. This dissertation is divided into two chapters, which are presented here as independent manuscripts already in the standards required for journals chosen for publication, whose norms are attached to this dissertation. The chapters are: Lamiaceae in Rio Grande do Norte, Brazil, where is the taxonomic and floristic treatment of the Lamiaceae family in the state of Rio Grande do Norte. In this study, 30 species were recorded, of which 14 are exotic, cultivated or cultivated, and 16 are native species. The species Hyptis brevipes Poit. e Vitex rufescens A.Juss. occur only in the Atlantic Forest domain, while Amasonia campestris (Aubl.) Moldenke, Eriope macrostachya Mart. Harley & J. F.B.Pastore, Mesosphaerum pectinatum (L.) Kuntze, Hyptis lantanifolia Poir., Mesosphaerum sp., Vitex gardneriana Schauer, Vitex schaueriana Moldenke, occur only in the Caatinga domain. The species Mesosphaerum suaveolens (L.) Kuntze and Marsypianthes chamaedrys (Vahl.) Kuntze were the ones that presented the largest distribution in the territory of the state. In the second chapter, New records, conservation assessments and distribution of Lamiaceae in Rio Grande do Norte, northeastern, Brazil, is presented the Status of conservation of the species of Lamiaceae and their distribution in the RN including the species and genera mentioned for the first time for the state. Among the native species, three were classified as 'Threatened', four as 'Vulnerable', three are 'Least Concern', two are 'Near Threatened' and four are 'Data Deficient'. The phytogeographical domain Caatinga, a Seasonally Dry Tropical Forest (SDTF), has the highest number of Lamiaceae species, although less than 1% of this region is protected by conservation units. This study reveals the worrying state of conservation of the Lamiaceae family in the NR and the need for conservation actions such as the creation of new conservation units to preserve the quality of the habitat and the remaining natural formations and to monitor populations in the wild.

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2017-03-30T17:49:38Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação - Camila Miranda Barbosa.pdf: 2266282 bytes, checksum: 8e483f742cbf0b10a05321744d93decd (MD5) / Made available in DSpace on 2017-03-30T17:49:38Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação - Camila Miranda Barbosa.pdf: 2266282 bytes, checksum: 8e483f742cbf0b10a05321744d93decd (MD5) Previous issue date: 2016-02-24 / CNPQ / O licuri (Syagrus coronata) é uma palmeira que floresce e frutifica durante o ano inteiro, tendo grande importância ecológica e econômica, uma vez que fornece hábitat e alimento para diversos seres vivos, inclusive para a subsistência de populações humanas. Em populações nativas encontradas no Parque Nacional do Catimbau, a fenologia da espécie foi monitorada em quatro áreas (total de 120 indivíduos). Também foram identificados os visitantes florais, a composição química dos odores florais e a variação de temperatura das flores durante a antese, levando em consideração as fases reprodutivas (feminina e masculina), o sexo das estruturas reprodutivas (flores pistiladas e estaminadas) e o período do dia (manhã e noite). O fitness reprodutivo foi comparativamente analisado para polinização diurna vs noturna, entomófila vs anemófila. Amostras de odores florais foram coletadas através de “headspace” dinâmico a partir de flores pistiladas e estaminadas, bem como nas suas respectivas brácteas. O estudo da fenologia evidenciou duas áreas sazonais, enquanto duas outras produziram eventos contínuos de reprodução. A riqueza e abundância de visitantes florais foram maiores nas inflorescências masculinas que nas femininas. O fitness reprodutivo não mostrou diferença entre os tratamentos de polinização. Por sua vez, análises de odor floral demonstraram diferenças de compostos isolados nas brácteas e inflorescências, mas não entre as fases reprodutivas; a quantidade de odor emitido diferiu nas brácteas nas fases femininas e masculinas, mas não nas inflorescências, as quais apresentaram quantidades similares de compostos. Não foi evidenciado fenômeno de termogênese floral, nem ao longo do dia, nem entre as fases reprodutivas. Estratégias como o fornecimento de recursos em abundância e hábitat para visitantes florais, liberação diferenciada de odor e floração contínua, podem estar associadas à garantia do fluxo gênico dentro e entre populações dessa espécie de Syagrus. / Licuri (Syagrus coronata) is a palm tree that blooms and bears fruit throughout the year, having an ecological and economic importance, as it provides habitat and food for many living beings, including for the livelihoods of human populations. In native populations, found in Catimbau National Park, the phenology of species was monitored in four areas (total 120 individuals). Also flower visitors were identified, the chemical composition of floral scents and temperature variation of flowers at anthesis, taking into account the reproductive stages (male and female), sex of the reproductive structures (pistillate and staminate flowers) and the period the day (morning and evening). The reproductive fitness was comparatively analyzed for day vs. night pollinated and entomophilous vs anemophilus. Samples of floral odours were collected through "headspace" dynamic from pistillate and staminate flowers as well as in their respective bracts. The study of phenology showed two seasonal areas, while two others produced continuous reproductive events. The richness and abundance of floral visitors were higher in male than in female inflorescences. The reproductive fitness showed no difference between pollination treatments. In turn, floral odor analysis showed differences in isolated compounds in the bracts and flowers, but do not between the reproductive stage; the amount of odor emitted differed in the bracts in male and female phases, but not in inflorescences, which showed similar amounts of compounds. Floral thermogenesis phenomenon was not evidenced neither throughout the day nor between reproductive stages. Strategies such as providing abundant resources and habitat for floral visitors, differentiated release of odor and continuous flowering, may be associated with the guarantee of gene flow within and among populations of this species of Syagrus.

Tropical forests are storehouses of more thanhalf of the world‘s biodiversity and play a key role in global carbon, water and energy cycles. However, as a consequence of rapid anthropogenic climate change, biodiversity and climate functions of these forests are under a threat. Climate is changing not only in mean state but its variability is increasing, with extreme events such as droughts, heat waves and storms also rising. Water is fundamental to plants‘ existence, and in the tropics, is a key determinant of plant species‘richness, composition, growth and survival. There is thus an increasing interest in understanding how changing rainfall may cause functional changes in forests or change their species composition. Therefore, the overarching goal of thisdissertation was to understand the impact of water variability on tropical forest tree growth and vulnerability to drought.Forest tree growth along spatial and temporal rainfall gradientsObservational studies that measure whole forest tree growth along spatial or temporal gradients of rainfall are the most common way of formulating forest growth response curves to water availability, when manipulative experiments are cost-prohibitive or impractical (fire or large mammal disturbance). In the tropics, since very few species show anatomically distinct tree rings, estimating tree growth from trunk diameter is the standard practice to obtain growth patterns across species. However, this method—of equating woody growth to diameter change--is susceptible to bias from water-induced stem flexing. In the absence of bias correction, temporal variability in growth is likely to be overestimated and incorrectly attributed to fluctuations in resource availability, especially in forests with high seasonal and inter-annual variability in water. This problem has been largely ignored in the absence of any corrective measure and due to under-appreciation of the magnitude of error. While diameter re-censuses in permanent sampling plots (PSPs) have been most commonly done at 3-5 year scale (using a graduate tape), increasingly they are done at seasonal and annual scales (using band dendrometers) to closely match variation in rainfall, the scales at which hydrostatic bias may be greater in magnitude relative to woody growth. Besides, along a spatial rainfall gradient, inter-annual variability in water may vary, causing systematic differences in the hydrostatic bias for forests along the gradient. Therefore, one broad objective of this thesis was to evaluate the problem of hydrostatic bias in whole forest growth-rainfall relationship at annual and supra-annual scales, for temporal as well as spatial rainfall gradients and propose and test a novel corrective solution.Further, it also examines if growth-diameter relationship vary along the spatial gradient, which it may arise due to differences in light environments and/or disturbance history and species composition. The missing link of Eco-hydrology Differential responses of tree species in terms of growth and survival to variation in water that they can access, the proximate cause is likely shaped through their life-history strategies, the ultimate cause. However, we neither know the depths at which the diverse tree species in a forest draw water from and its dynamics, nor variation in water at those depths vis-à-vis rainfall patterns—for lack of appropriate methods. This has been a key missing link in understanding how water shapes trees‘ life-history strategies, their demographic trade-offs and co-existence, and also our predictive ability to determine species-specific responses to changing rainfall patterns, especially droughts. Since droughts are highly stochastic events and trees‘ responses to their drought ―experiences‖ may be revealed at decadal scales, long-term evaluations are key. Therefore, the second broad objective of this thesis was to develop a framework to determine trees’ water uptake depths, variation in water availability at those depths and trees’ demographic responses over multiple decades. From this, to understand how belowground hydrology shapes drought-vulnerability, demographic trade-offs and coexistence of forest tree species. This thesis titled—Eco-Hydrology of a Seasonally Dry Tropical Forest: Tree Growth, Belowground Water Dynamics and Drought-Vulnerability—is organized as follows: Chapter 1 lays down an introduction to the thesis, followed by a description of the study site and datasets used in the thesis in Chapter 2. This thesis uses a variety of methods and multiple datasets, all of which are from the protected Seasonally Dry Tropical Forests of the Western Ghats in southern India in the Mudumalai and Bandipur National Parks. It is then followed by three data chapters: Chapter 3 describes the seasonal fluctuations in a five year long (1980-1985) tree diameter time series (using dendrometers) of a Seasonally Dry Tropical Forest in Bandipur National Park to illustrate the issue of hydrostatic stem-flexing. It investigates the possibility that band dendrometers may themselves underestimate stem shrinkage at diurnal or seasonal scale. It also evaluates if there could be a best season and time of the day for undertaking forest diameter censuses that can minimize hydrostatic bias. Chapter 4(published in Forest Ecology and Management)measures the hydrostatic bias in a sample of trees in a 50 ha PSP of a Seasonally Dry Tropical Forest in Mudumalai National Park, and proposes a novel way to correct this bias at the whole community level in the 20 year long 4-year interval growth time series. Chapter 5 (in review with Environmental Research Letters) investigates and presents two new confounding factors in growth-rainfall relationships along a spatial rainfall gradient: hydrostatic bias and size-dependency in growth rates. For this it evaluates forest tree growth estimates in seven 1-ha PSPs (~800 trees, 3-year annual time series 9using dendrometers) along a 1000 mm rainfall gradient spanning a mesic savanna-moist forest transition in Mudumalai National Park. Using the period for which seasonal diameter time series was available (2 yrs), it evaluates if the extent of seasonal fluctuations systematically vary along the gradient—most likely due to hydrostatic stem flexing. It also describes the presence of an anomalous size-diameter relationship in the mesic savanna from a large plots (50 ha PSP, diameter records using graduated tape). These observations are then used to draw insights for ―space for time‖ substitution modeling. Chapter 6 (in prep for Nature Plants) analyses belowground water environments of trees over two decades (1992-2012), a period that includes a prolonged and intense drought, in the 50 ha PSP of a Seasonally Dry Tropical Forest in Mudumalai. It uses a locally parametarised dynamic hydrological model in which site rainfall is also a forcing variable. It then develops a novel dynamic growth model and inversely estimates water uptake depths for adult trees of all common species (include ~9000 trees) in the PSP from their above-ground growth patterns over two decades vis-à-vis belowground water availability at multiple depths. It then examines if species‘ water uptake depth obtained thus is a predictor of their drought-driven mortality. Finally, this is used to evaluate the hydrological niche partitioning tree species operate under and how that drives their water uptake strategies, demographic trade-offs, and drought-vulnerability. Summarizes the thesis and suggests future directions