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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.

Leaf traits have long been used to classify and characterise species in natural ecosystems. In addition, leaf traits provide important information about plants’ strategies for the use of resources and can be used to improve our understanding of ecosystem level processes such as nutrient cycling and carbon allocation. To explore the linkages between leaf traits and productivity, we worked in two resource-limited ecosystems (a grassland and a forest), and used leaf traits to understand how species respond to changes in available resources and their relationship to ecosystem processes. We worked in a species rich limestone-grassland located in central England, which has been subjected to long-term climatic manipulation (winter warming, summer drought and extra summer rainfall). We characterised species composition in terms of their identity, abundance and leaf structural properties (nitrogen content and leaf mass per area (LMA)) in the main treatments and the control. We found that change in species abundance was the most important factor to understand the differences in productivity (above ground biomass and total foliar nitrogen). We then measured CO2 exchange at ecosystem level, using a chamber technique, and assessed the treatments’ effect on the gross primary productivity (GPP) and ecosystem respiration (Reco). GPP and Reco were controlled by soil moisture and above ground biomass but also influenced by the conditions experienced during the growing season prior to the measuring period. Our second location was a post-disturbance chronosequence in a seasonally dry tropical forest in Costa Rica and we used leaf level gas exchange measurements to explore the role of nitrogen (N) and phosphorus (P) on the temporal-spatial variation of photosynthesis of dominant species. We found that photosynthetic efficiency was strongly linked to leaf N and P content, but that there was an important seasonal pattern on this relationship likely associated to P remobilization. Additionally we found seasonal changes in resources (water, nutrients) had a larger impact on the photosynthetic parameters than changes along the chronosequence. The two ecosystems studied for this thesis are contrasting in their physiognomy, species composition and climate, but are also characterised by species whose structural traits (high LMA and high C:N ratio) are likely to have a significant impact on the nutrient cycling processes. We learned that leaf traits provide important information about species strategies and their usage of resources and they can also aid to address questions at ecosystem level in time and space, either through simple aggregation or as emergent properties. Additionally, the traits explored are important input information to up-scale processes from leaf to the ecosystem level, a step needed to address the effect changes in resources will have on the seasonally dry tropical forest and grasslands, which represent a significant fraction of the total global carbon storage.

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.

Northern environments are often characterised by large seasonal and annual fluctuations in food abundance. In this thesis, I examined how arctic foxes (</i>Alopex lagopus</i>) used seasonally superabundant foods (geese and their eggs) and how access to these foods influenced population dynamics of arctic foxes. I addressed this against a backdrop of variation in lemming and vole abundance (small mammals hereafter) the main foods of arctic foxes throughout most of their range. Field work was done at the large goose colony at Karrak Lake and surrounding areas in the Queen Maud Gulf Bird Sanctuary in Nunavut, Canada, in the spring and summers of 2000 to 2004. <p> Behavioural observations of individually-marked arctic foxes showed that they took and cached 2,000-3,000 eggs per fox each year and that the rate at which they took eggs was largely unrelated to individual attributes of foxes (e.g. sex, size, and breeding status) and nesting distribution of geese. Further, the rate at which foxes took eggs varied considerably within individuals in that foxes were efficient at taking eggs at times and inefficient at other times. This may have resulted from foxes switching between foraging actively and taking eggs opportunistically while performing other demands such as territorial behaviours. <p>Comparison of stable isotope ratios (13C and 15N) of fox tissues and those of their foods showed that the contribution of cached eggs to arctic fox diets was inversely related to collared lemming (<i>Dicrostonyx torquatus</i>) abundance. In fact, the contribution of cached eggs to overall fox diets increased from <28% in years when collared lemmings were abundant to 30-74% in years when collared lemmings were scarce. Furthermore, arctic foxes used cached eggs well into the following spring (almost 1 year after eggs were acquired) a pattern which differs from that of carnivores generally storing foods for only a few days before consumption. <p>A field-study of experimental caches showed that survival rate of these caches was related to age of cache sites in the first year of the study (e.g. 0.80 and 0.56 per 18-day period for caches from new and 1 month old cache sites, respectively) and departure by geese after hatch in the second year of the study (e.g. 0.98 and 0.74 per 18-day period during and after goose nesting, respectively). Food abundance and deterioration of cache sites (e.g. loss of soil cover and partial exposure of caches) were, thus, important factors affecting cache loss at Karrak Lake. Further, annual variation in the importance of these factors suggests that strategies to prevent cache loss are not fixed in time but vary with existing conditions. Evolution of caching behaviours by arctic foxes may, thus, have been shaped by multiple selective pressures. <p>Comparisons of reproductive output and abundance of arctic foxes inside and outside the goose colony at Karrak Lake showed that (i) breeding density and fox abundance were 2-3 times higher inside the colony than they were outside the colony and (ii) litter size, breeding density, and annual variation in fox abundance followed that of small mammal abundance. Small mammal abundance was, thus, the main governor of population dynamics of arctic foxes whereas geese and their eggs elevated fox abundance and breeding density above that which small mammals could support. These results highlight both the influence of seasonal and annual variation on population dynamics of consumers and the linkage between arctic environments and wintering areas by geese thousands of kilometres to the south.

Northern environments are often characterised by large seasonal and annual fluctuations in food abundance. In this thesis, I examined how arctic foxes (</i>Alopex lagopus</i>) used seasonally superabundant foods (geese and their eggs) and how access to these foods influenced population dynamics of arctic foxes. I addressed this against a backdrop of variation in lemming and vole abundance (small mammals hereafter) the main foods of arctic foxes throughout most of their range. Field work was done at the large goose colony at Karrak Lake and surrounding areas in the Queen Maud Gulf Bird Sanctuary in Nunavut, Canada, in the spring and summers of 2000 to 2004. <p> Behavioural observations of individually-marked arctic foxes showed that they took and cached 2,000-3,000 eggs per fox each year and that the rate at which they took eggs was largely unrelated to individual attributes of foxes (e.g. sex, size, and breeding status) and nesting distribution of geese. Further, the rate at which foxes took eggs varied considerably within individuals in that foxes were efficient at taking eggs at times and inefficient at other times. This may have resulted from foxes switching between foraging actively and taking eggs opportunistically while performing other demands such as territorial behaviours. <p>Comparison of stable isotope ratios (13C and 15N) of fox tissues and those of their foods showed that the contribution of cached eggs to arctic fox diets was inversely related to collared lemming (<i>Dicrostonyx torquatus</i>) abundance. In fact, the contribution of cached eggs to overall fox diets increased from <28% in years when collared lemmings were abundant to 30-74% in years when collared lemmings were scarce. Furthermore, arctic foxes used cached eggs well into the following spring (almost 1 year after eggs were acquired) a pattern which differs from that of carnivores generally storing foods for only a few days before consumption. <p>A field-study of experimental caches showed that survival rate of these caches was related to age of cache sites in the first year of the study (e.g. 0.80 and 0.56 per 18-day period for caches from new and 1 month old cache sites, respectively) and departure by geese after hatch in the second year of the study (e.g. 0.98 and 0.74 per 18-day period during and after goose nesting, respectively). Food abundance and deterioration of cache sites (e.g. loss of soil cover and partial exposure of caches) were, thus, important factors affecting cache loss at Karrak Lake. Further, annual variation in the importance of these factors suggests that strategies to prevent cache loss are not fixed in time but vary with existing conditions. Evolution of caching behaviours by arctic foxes may, thus, have been shaped by multiple selective pressures. <p>Comparisons of reproductive output and abundance of arctic foxes inside and outside the goose colony at Karrak Lake showed that (i) breeding density and fox abundance were 2-3 times higher inside the colony than they were outside the colony and (ii) litter size, breeding density, and annual variation in fox abundance followed that of small mammal abundance. Small mammal abundance was, thus, the main governor of population dynamics of arctic foxes whereas geese and their eggs elevated fox abundance and breeding density above that which small mammals could support. These results highlight both the influence of seasonal and annual variation on population dynamics of consumers and the linkage between arctic environments and wintering areas by geese thousands of kilometres to the south.

Muskeg or peat deposits cover large areas in northern Manitoba. Test sections of a newly constructed highway on peat were instrumented to investigate their performance and to develop more economical means of construction method. Test Section ‘A’ was constructed with geotextile base layer while Section ‘B’ was with geotextile and corduroys (timber logs). The test sections were constructed during winter for ease in mobilizing construction equipment at the site when the ground was frozen and were instrumented to observe its behaviour and performance. Settlements were measured using monitoring plates and pins. Ground temperatures were measured using thermistors. Porewater pressures were measured using vibrating wire piezometers. Peat in the study area has an average thickness of 4m, with the upper layer classified as fibrous and the lower layer as amorphous with strong to complete decomposition. Standard laboratory tests were conducted on bored samples from the site. Hydraulic conductivity tests were carried out at different vertical pressures to determine its permeability. Thermal conductivity was determined at frozen and unfrozen state of peat. Conventional incremental oedometer tests were conducted to determine the compressibility parameters and secondary compression indices of the peat layers. Constant-rate-of-strain (CRS) tests were also performed to supplement the results obtained from the conventional method. Isotropically-Consolidated Undrained (CIŪ) triaxial tests were carried out to determine the shear strength of peat. A commercially-available computer program was used in the numerical modelling to simulate the field performance of the instrumented sections. The results from numerical modelling were reasonably close to the measured values in the field. Laboratory-scale physical modelling was undertaken to understand further the operating mechanisms involved in the performance of the two test sections under a more controlled environment. Artificial transparent clay that has similar deformation properties with most of the natural clays and peats was used as foundation material. It allows determination of spatial deformations beneath the embankment using Particle Image Velocimetry (PIV) technique. The load-settlement behaviour in the field was also reasonably simulated in the laboratory-scaled physical model. Deformation patterns from PIV indicate that embankment with geotextile layer and corduroy has smaller settlements and lateral movements in the foundation compared to that of the embankment with only geotextile layer.

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.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21971号 / 農博第2361号 / 新制||農||1071(附属図書館) / 学位論文||R1||N5222(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 大澤 晃, 教授 髙部 圭司, 教授 小杉 緑子 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2016-01-20T22:46:00Z No. of bitstreams: 1 GR?NIVEL MOTA DA COSTA (1).pdf: 2200564 bytes, checksum: 3828a984c3a6ee25ef6f2d93f10132ad (MD5) / Made available in DSpace on 2016-01-20T22:46:00Z (GMT). No. of bitstreams: 1 GR?NIVEL MOTA DA COSTA (1).pdf: 2200564 bytes, checksum: 3828a984c3a6ee25ef6f2d93f10132ad (MD5) Previous issue date: 2014-09-24 / The caatinga vegetation of northeastern Brazil mainly occurs in Pre-Cambrian-crystalline-derived soils and sedimentary-basin-derived sandy soils. Recent evidence has shown variations in the dynamics, structure and floristic composition of the caatinga, which justifies the need for studies focusing on different substrates. A floristic study of the caatinga ecoregions Depress?o Sertaneja Meridional and Raso da Catarina in the municipality of Tucano, Bahia, Brazil, is of special interest because both substrates occur in a local scale, letting the opportunity to broaden our knowledge on ecological heterogeneity within the Caatinga biome. In the current study we carried out a floristic survey of 14 sites distributed throughout the ecoregions of caatinga in Tucano. We found high species diversity in the caatingas of Tucano when compared to other areas in northeastern Brazil. A total of 451 species, 288 genera, and 82 families were collected. The most species rich families are Leguminosae and Euphorbiaceae. There occur 226 species in the sites on crystalline basement, whereas 284 species were collected in the sandy areas. The ecoregions were only 13% similar in floristic composition. We found strong differences between the ecoregions with respect to floristic composition and predominant plant habit as proxy for phytophysiognomy. Overall, our results reinforce the hypothesis of two distinct biotas that assembly the caatinga dry woodlands. / A vegeta??o de caatinga do nordeste brasileiro ocorre principalmente sobre solos derivados de rochas cristalinas pr?-cambrianas e sobre cobertura arenosa de bacias sedimentares. Evid?ncias recentes t?m demonstrado varia??es na din?mica, estrutura e composi??o flor?stica da caatinga, o que fundamenta a necessidade de estudos com enfoque nos diferentes substratos. O presente estudo flor?stico das ecorregi?es de caatinga, Depress?o Sertaneja Meridional e Raso da Catarina, no munic?pio de Tucano, Bahia, ? de especial interesse porque h? esses dois substratos em escala geogr?fica local, permitindo ampliar o conhecimento sobre a heterogeneidade do Dom?nio da Caatinga. Neste trabalho ? apresentado um invent?rio flor?stico de 14 localidades nas duas ecorregi?es de caatinga. Em conjunto, as caatingas amostradas apresentaram uma alta riqueza flor?stica em compara??o com outras ?reas no nordeste do Brasil. Foram coletadas 451 esp?cies, 288 g?neros e 82 fam?lias. A maior riqueza em esp?cies foi das Leguminosae, seguida por Euphorbiaceae. Nas localidades sobre substrato derivado do embasamento cristalino ocorreram 226 esp?cies, enquanto nas de substrato arenoso ocorreram 284 esp?cies. A propor??o de esp?cies em comum nas duas ecorregi?es foi apenas 13%. Diferen?as em composi??o flor?stica refor?am a hip?tese de duas biotas distintas associadas aos dois principais tipos de substrato, que comp?em a vegeta??o da caatinga.