High Proportion Of Species Research Articles

Insecticide susceptibilities of Hydrometra species (Hemiptera: Hydrometridae), including an endangered species, inhabiting paddy fields in Japan

Freshwater ecosystems tend to have the highest proportion of species threatened with extinction. Paddy fields provide alternative habitats for many species inhabiting wet hinterlands of rivers. This study examined the susceptibilities of three hydrometrid species, Hydrometra procera Horvath (Hemiptera: Hydrometridae), H. albolineata (Scott) (Hemiptera: Hydrometridae), and H. okinawana Drake (Hemiptera: Hydrometridae), inhabiting paddy fields in Japan to seven insecticides that were frequently applied to paddy fields, and evaluated the effect of each insecticide according to the hazard assessment classes by the International Organization for Biological Control and Integrated Control of Noxious Animals and Plants/West Palearctic Regional Section. Etofenprox, imidacloprid, and fenobucarb were found to be seriously harmful to the third instar nymphs of the three hydrometrid species. Buprofezin (an insect growth regulator) was also evaluated as seriously harmful based on the mortality at the third instar of the three species before the completion of molting to the fourth instar. Etofenprox, imidacloprid, and buprofezin were particularly harmful even at low concentrations to H. procera. Some of these insecticides have been heavily used in paddy fields since the 1950s or 1960s. It was around this time when the endangered species, H. albolineata populations began to decline drastically. Our results suggested that heavy use of these insecticides is one of the factors that caused the decline in H. albolineata populations.

A hairy situation: Plant species in warm, sunny places are more likely to have pubescent leaves

AbstractAimLeaf pubescence has several important roles, including regulating heat balance, reducing damage from UV radiation, minimizing water loss and reducing herbivory. Each of these functions could affect a plant's ability to tolerate the biotic and abiotic stresses encountered in different parts of the world. However, we know remarkably little about large scale biogeographic patterns in leaf pubescence. Our aims were: (a) to determine whether a higher proportion of species have pubescence at sites where it is hot, dry and solar radiation is high, and (b) to quantify the latitudinal gradient in pubescence.LocationAustralia.TaxonVascular land plants.MethodsWe compiled data on the presence/absence of pubescence on mature photosynthetic organs for 4,183 species, spanning 107 families. We combined these data with over 1.9 million species occurrence records from the Atlas of Living Australia to calculate the proportion of species with pubescence in 3,261 grid cells spanning the Australian continent.ResultsThe proportion of pubescent species was most closely related to solar radiation (R2 = 0.33), followed by maximum temperature in the warmest month (R2 = 0.30). Mean annual precipitation was very weakly related to pubescence (R2 = 0.01). We found a significant negative relationship between latitude and pubescence (R2 = 0.19), with the average percentage of species with pubescence dropping from 46% at 10° S to 35% at 44° S. This cross‐species relationship remained significant after accounting for phylogenetic relationships between species. We found that a quadratic model explained more variation in pubescence across latitudes than did a linear model. The quadratic model shows a peak in the proportion of pubescent species at 19° S (within the tropics).Main conclusionsOur findings are consistent with the idea that leaf pubescence may have a protective function in areas with high solar radiation and high temperatures. Our data are also consistent with the idea that species towards the tropics should be better defended than are species at higher latitudes.

Tropical terrestrial invertebrates—Where to from here?

AbstractThere are over one million described invertebrate species on Earth, the majority of which are likely to inhabit the highly biodiverse rain forests around the equator. These are some of the most vulnerable ecosystems on Earth due to the pressures of deforestation and climate change with many of their inhabitants at risk of extinction. Invertebrates play a major role in ecosystem functioning from decomposition and nutrient cycling to herbivory and pollination; however, while our understanding of these roles is improving, we are far from being able to predict the consequences of further deforestation, climate change, and biodiversity loss due to the lack of comparative data and the high proportion of species which remain to be discovered. As we move into an era of increased pressure on old‐growth habitats and biodiversity, it is imperative that we understand how changes to invertebrate communities, and the extinction of species, affect ecosystems. Innovative and comprehensive methods that approach these issues are needed. Here, we highlight priorities for future tropical terrestrial invertebrate research such as the efficiency of sustainable land management, exploration of innovative methods for better understanding of invertebrate ecology and behavior, and quantifying the role of invertebrates in ecosystem functioning.

Species traits linked with range shifts of Chinese birds

Range shifts are important species response to climate change and anthropogenic activities. While many studies have suggested that species traits are also important predictors of range shifts, they are mainly conducted in Europe and North America, and more importantly there are still many controversies about the roles of species traits. As far as we know, this is the first study in China linking bird species traits with range shifts. We aimed to answer two questions: 1) which order and family have most bird species with range shifts? 2) which traits are most associated with the bird species range shifts in China? A total of 204 species (14% of all bird species in China) had changed their ranges. Although passeriformes (126 species) and muscicapidae (23 species) had the most species with range shifts, the order and family with highest proportion of species with range shifts were cuculiformes (40%), rostratulidae (100%) and artamidae (100%). Our results also showed that range shifts of Chinese birds were positively correlated with geographical range size, habitat specificity, trophic level, and negatively correlated with body size. Notably, all the four traits were included in the combination of traits most associated with range shifts, suggesting that priority should be given to birds with large body size, low habitat specificity, low tropical level and small geographical size. Because these species could not adapt the effects of climate change and anthropogenic activities in time, and would then face an increased risk of extinction. As China harbors high levels of overall bird species richness, threatened and endemic bird species richness, as well as large human population, this study is of great importance for the bird diversity conservation in China.

Islands in a green ocean: Spatially structured endemism in Amazonian white‐sand vegetation

AbstractHere, we examine the influence of the spatial distribution of open white‐sand campina (WSC) in the Amazon on the species richness and beta diversity of their vascular plants. It is well known that beta diversity tends to increase with geographical distance, but the influence of habitat insularity on floristic composition and endemism is still unclear. We surveyed WSC in central and southwestern Amazon, generating lists of species occurrences by rapid‐inventory techniques to evaluate the influence of island area and connectivity on alpha and beta diversity among five landscapes in the Amazon Basin. Effects of insularity were assessed by comparing alpha and beta diversity within and among landscapes. A high proportion of species (~74%) and genera (~50%) were restricted to only one of the five landscapes and only three species and 28 genera were shared among all landscapes. At the regional scale, beta diversity increased significantly with distance. Partitioning of beta diversity showed that landscapes of higher connectivity have greater turnover and lower nestedness. We conclude that the flora of WSC is highly structured at regional scales, while at the local scale structure is evident only in low connectivity landscapes. Landscape metrics apparently play an important role in shaping patterns of diversity regionally as a result of processes operating at larger geographical scales. This emphasizes that conservation policy should not be local in its geographical focus and should account for connectivity at larger scales. This study is the first to empirically and explicitly evaluate the pattern of endemism in lowland WSC in the Amazon.Abstract in Porteges is available with online only

Using the scientific listing process to better understand climate change risk to threatened species and ecological communities in New South Wales

Anthropogenic climate change presents a major threat to all levels of biodiversity – from populations to ecosystems. Threatened species and ecological communities are particularly at risk because they generally possess characteristics that increase their vulnerability to extinction. Here we review the conservation assessments of 414 threatened species and 108 ecological communities in the state of New South Wales (NSW) Australia, to explore climate change extinction risk. We found only 13% of threatened species and 24% of threatened ecological communities have climate change identified as a threat. Amphibians had the highest proportion of species with a climate change threat identified (37%), followed by mammals (25%), birds (17%), reptiles (15%) and plants (10%). The sample sizes of freshwater algae and marine mammals were too small to be considered. Threatened species and ecological communities that had climate change listed as a threat were predominately associated with wet and montane habitats, highlighting the vulnerability of these environments. The estimates of the extinction threat from climate change to species and ecological communities in NSW are likely to be highly conservative. We suggest that climate change adaptation strategies be incorporated into all levels of biodiversity management, from threatened species management plans to landscape level management.

Bird responses to housing development in intensively managed agricultural landscapes

Housing a growing human population is a global issue and designing environmentally friendly developments requires identifying the species likely to be negatively impacted and finding mitigation solutions. Existing studies that consider fragmentation of natural habitats have limited application in countries such as Britain where a prime target for development is agricultural land where decades of intensive management have already diminished biodiversity. Here I used citizen science data on the abundance of 146 breeding and wintering birds to develop models linking abundance to human population density and habitat features. I used these as a proxy for the urbanisation process, finding that impacts of urbanisation were species-specific and context dependent. Low-density developments benefited a high proportion of birds, with wetland birds benefitting most and farmland birds least, but as human densities increased further, up to 75% of species were negatively impacted. Almost half of species currently occurring at 14 flagship residential development sites were predicted to decline based on projected human population density increases, with a third predicted to increase. Presence of wetlands, canopy cover and patches of trees all benefited certain species but efforts to identify more detailed habitat associations were hampered by collinearity among variables. I conclude that even in heavily degraded agricultural landscapes, a high proportion of species will be negatively impacted by residential development and that some will require spared land to persist in the wider landscape. As no single habitat benefited the entire bird community, urban planners wishing to design bird-friendly developments will need to make difficult decisions over which aspects of the bird community to prioritise.

Endemics and Cosmopolitans: Application of Statistical Mechanics to the Dry Forests of Mexico.

Data on the seasonally dry tropical forests of Mexico have been examined in the light of statistical mechanics. The results suggest a division into two classes of species. There are drifting populations of a cosmopolitan class capable of existing in most dry forest sites; these have a statistical distribution previously only observed (globally) for populations of alien species. We infer that a high proportion of species found only at a single site are specialists, endemics, and that these prefer sites comparatively low in species richness.

Assessing the vulnerability of Africa's freshwater fishes to climate change: A continent-wide trait-based analysis

Climate change is a key driver of biodiversity loss across the globe, and freshwater fishes are predicted to be among the most vulnerable taxa. African freshwater ecosystems are home to one of the most unique and diverse ichthyo-faunas on the planet, and freshwater fish species provide essential livelihoods for millions of people living in riparian communities across the continent. Although nearly one sixth of African freshwater fishes have been designated as endangered or vulnerable to extinction by the IUCN Red List assessment, the effects of climate change on these species have not been explored on a continent-wide scale. In this study, we present the first trait-based climate change vulnerability assessment (CCVA) comprising the majority (85%) of Africa's currently described freshwater fishes. We assembled data relating to three dimensions of vulnerability including sensitivity, adaptive capacity, and exposure. In addition, we developed an index of ‘conservation value’ based on traditional conservation metrics including extinction risk, endemism, and provision of ecosystem services. We found that almost 40% of African freshwater fishes are vulnerable to climate change, mostly owing to the many species with highly specialized habitat and life-history requirements, and because of the numerous anthropogenic stressors they face. High proportions of species within the Nothobranchiidae and Cichlidae families were found to be vulnerable. Regions with high frequencies of vulnerable species included the African rift valley lakes, the Congo River drainage, and the coastal rivers of West Africa. Several important data deficiencies were identified relating to species' population sizes, genetic variability, and life history traits, and constitute priority research areas for the future. In addition, we highlighted some cases where traditional conservation approaches overlook species and regions that are predicted to be threatened by climate change.

Exploring the power of Bayesian birth-death skyline models to detect mass extinction events from phylogenies with only extant taxa.

Mass extinction events (MEEs), defined as significant losses of species diversity in significantly short time periods, have attracted the attention of biologists because of their link to major environmental change. MEEs have traditionally been studied through the fossil record, but the development of birth‐death models has made it possible to detect their signature based on extant‐taxa phylogenies. Most birth‐death models consider MEEs as instantaneous events where a high proportion of species are simultaneously removed from the tree (“single pulse” approach), in contrast to the paleontological record, where MEEs have a time duration. Here, we explore the power of a Bayesian Birth‐Death Skyline (BDSKY) model to detect the signature of MEEs through changes in extinction rates under a “time‐slice” approach. In this approach, MEEs are time intervals where the extinction rate is greater than the speciation rate. Results showed BDSKY can detect and locate MEEs but that precision and accuracy depend on the phylogeny's size and MEE intensity. Comparisons of BDSKY with the single‐pulse Bayesian model, CoMET, showed a similar frequency of Type II error and neither model exhibited Type I error. However, while CoMET performed better in detecting and locating MEEs for smaller phylogenies, BDSKY showed higher accuracy in estimating extinction and speciation rates.

Medicinal plant species used in the treatment of skin diseases in Katabi Subcounty, Wakiso District, Uganda

Background : The use of medicinal plants in primary healthcare is central among rural communities in Uganda given the expensive and often inaccessible conventional healthcare. Skin diseases pose a serious health risk given the challenge of HIV-AIDS whose opportunist infections manifest as skin complications.The study identified and documented plant species used to manage skin infections, plant parts used, methods of preparation and administration of herbal remedies. Methods: An ethnobotanical survey of plant species used to treat skin diseases was conducted in Katabi Sub-County, Wakiso District in Uganda using semi structured interviews. Twenty villages were surveyed with at least three respondents from each village interviewed. A questionnaire, checklist, and personal observation were the research instruments used. Descriptive statistics were used to present the data. Results: A total of 52 plants belonging to 33 families were documented. The highest proportion of species (25%) was used against fungal infections. Other proportions of plants against their respective diseases were; 24%, 20%, 16% and 16% for allergies, wounds, skin rash and warts respectively. The commonly used species were Iboza multiflora , Psorospermum febrifugum , Albizia coriaria , Hoslundia opposita , Justicia betonica , and Euphorbia tirucalli. Herbs (55%) were the main growth habit followed by trees (25%), shrubs (17%) and vines (and grasses) (3%). Leaves (54%) and flowers (11%) were the most commonly used plant parts while topical administration to affected parts was the major method of administration. Conclusion: Plant species used against skin diseases in Katabi Sub-County provides basic data for further studies focused on their pharmacological activity and conservation.

Binding Characteristics of Two Oxytocin Variants and Vasopressin at Oxytocin Receptors from Four Primate Species with Different Social Behavior Patterns.

A clade of New World monkeys (NWMs) exhibits considerable diversity in both oxytocin (OT) ligand and oxytocin receptor (OTR) structure. Most notable is the variant Pro8-OT, with proline instead of leucine at the eighth position, resulting in a rigid bend in the peptide backbone. A higher proportion of species that express Pro8-OT also engage in biparental care and social monogamy. When marmosets (genus Callithrix), a biparental and monogamous Pro8-OT NWM species, are administered the ancestral Leu8-OT, there is no change in social behavior compared with saline treatment. However, when Pro8-OT is administered, marmosets' sociosexual and prosocial behaviors are altered. The studies here tested the hypothesis that OTR binding affinities and OT-induced intracellular Ca2+ potencies would favor the native OT ligand in OTRs from four primate species, each representing a unique combination of ancestral lineage, breeding system, and native OT ligand: humans (Leu8-OT, monogamous, apes), macaques (Leu8-OT, nonmonogamous, Old World monkey), marmosets (Pro8-OT, monogamous, NWM), and titi monkeys (Leu8-OT, monogamous, NWM). OTRs were expressed in immortalized Chinese hamster ovary cells and tested for intact-cell binding affinities for Pro8-OT, Leu8-OT, and arginine vasopressin (AVP), as well as intracellular Ca2+ signaling after stimulation with Pro8-OT, Leu8-OT, and AVP. Contrary to our hypothesis, Pro8-OT bound at modestly higher affinities and stimulated calcium signaling at modestly higher potencies compared with Leu8-OT in all four primate OTRs. Thus, differences downstream from a ligand-receptor binding event are more likely to explain the different behavioral responses to these two ligands.

The Chironomidae of the Western Carpathian helocrenes: Metacommunity structuring and its drivers in unique habitats

Springs are unique and vulnerable habitats, which have always been rather out of focus of the scientist interest. Nevertheless, they frequently host very diverse and species-rich assemblages with high proportion of species more or less adapted to their unique environment and can act as biodiversity hotspots in some areas. The Western Carpathian springs are helocrene springs and represent wide variety of different habitat types, from mineral rich sparsely-vegetated or bryophytes-rich covered helocrenes to acidic peaty sites. Such diversification allows the creation of highly diverse assemblages, in which Chironomidae usually dominate in both species richness and abundance. The aim of this study was to provide a comprehensive overview of chironomid assemblages inhabiting the unique environment of spring fens and factors driving the metacommunity structuring and populations of individual taxa. We examined chironomid assemblages of 62 small, treeless helocrenes sites, which are highly isolated from each other by the terrestrial environment constituting dispersal barriers such as the east-west oriented mountain ridges and valleys. The sampling was performed to cover mesohabitat heterogeneity of study sites. Two main mesohabitats were sampled, the plot with flowing water and coarser substratum near water source (the lotic mesohabitat), and water-logged soil with standing water (the lentic mesohabitat). Study sites hosted nearly 100 chironomid taxa, both mesohabitats were inhabited by chironomid assemblages similar in number of species and abundances and the local environment was proved to be the main driver of compositional changes in chironomid assemblages as expected. Moreover, the significant spatial structure of assemblages was found at the lentic mesohabitat, while biotic interactions described by the abundance of Gammarus fossarum and taxa richness and abundances of predators did not significantly contribute to compositional changes in assemblages at any mesohabitat. Nevertheless, taxa-specific responses revealed populations of many taxa significantly affected by biotic interactions, especially at the more stable lotic mesohabitat, which is in concordance with suggested greater importance of biotic interactions at stable environment. Our results emphasized the importance of multilevel approach in community ecology for proper distinction between different mechanisms of metacommunity structuring. Biotic interaction such as competition can result into the same community patterns as environmental filtering, thus the involvement of detailed analyses of species requirements and interactions is necessary.

Small montane cloud forest fragments are important for conserving tree diversity in the Ecuadorian Andes

AbstractMontane tropical cloud forests, with their complex topography, biodiversity, high numbers of endemic species, and rapid rates of clearing, are a top global conservation priority. However, species distributions at local and landscape scales in cloud forests are still poorly understood, in part because few regions have been surveyed. Empirical work has focused on species distributions along elevation gradients, but spatial variation among forests at the same elevation is less commonly investigated. In this study, the first to compare tree communities across multiple Andean cloud forests at similar elevations, we surveyed trees in five ridge‐top forest reserves at the upper end of the ‘mid‐elevation diversity bulge’ (1900–2250 masl) in the Intag Valley, a heavily deforested region in the Ecuadorian Andes. We found that tree communities were distinct in reserves located as close as 10 to 35 km apart, and that spatially closer forests were not more similar to one another. Although larger (1500 to 6880 ha), more intact forests contained significantly more tree species (108–120 species/0.1 ha) than smaller (30 to 780 ha) ones (56–87 species/0.1 ha), each reserve had unique combinations of more common species, and contained high proportions of species not found in the others. Results thus suggest that protecting multiple cloud forest patches within this narrow elevational band is essential to conserve landscape‐level tree diversity, and that even small forest reserves contribute significantly to biodiversity conservation. These findings can be applied to create management plans to conserve and restore cloud forests in the Andes and tropical montane cloud forests elsewhere.

LITTERFALL PRODUCTION AT DIFFERENT SUCCESSIONAL STAGES IN A TROPICAL RAIN FOREST IN SOUTHERN BRAZIL

This study aims to evaluate the litterfall production of three areas in the tropical rain forest, in different successional stages, in the municipality of Siderópolis, Southern Santa Catarina state. Fifteen collectors of 0.25 m2 each were used, distributed in three transects per study area (A1, A2 and AR). The highest litterfall production occurred in AR (8,131 kg.ha-1), followed by A2 (4,253 kg.ha-1) and A1 (2,740 kg.ha-1). The AR area produced significantly more leaves, reproductive material and wastes. This can be explained by its more developed forest structure, with large trees, more closed canopy and greater number of epiphytes. On the other hand, areas A1 and A2 produced significant amounts of thin stems. These areas have a higher proportion of species in early successional stages, a higher density of thin trees and a more open canopy, being subject to winds, which could result in greater production and fall of branches. The results of this study highlight the importance of litterfall production in different successional stages, becoming necessary studies with this emphasis to understand the nutritional dynamics of ecosystems, especially those that have suffered strong impacts in the past, such as open-pit coal mining.

The structure and organisation of integral marine benthic communities in relation to sieve mesh size

Few studies consider meiofauna and macrofauna at the same time, even though both form parts of wider ecological networks, and fewer consider interactions between sample size, body size and spatial clustering. It has been suggested that the elements of the structure of the physical environment have fractal properties. If habitat complexity largely determines species diversity this leads to the prediction (for a single perfect fractal) that all organisms, regardless of size, will perceive the environment as equally complex and should have equivalent diversity and, as we move up the size spectrum, species composition should change in a regular and gradual fashion. This study examines the degree to which infaunal assemblage structure varies with mesh size, sample size and sample dispersion within two different areas of homogeneous intertidal sediment, a muddy sand and a coarse sand, in the Isles of Scilly, UK. In each area samples were extracted using a standard range of 5 mesh sizes (63, 125, 250, 500, 1000μm), with the sample areas and distances between samples scaled to the mesh size. All metazoans were identified to species level. Diversity and species composition did not show a gradual and even degree of change over the size range at either site. Instead, they showed a dramatic stepwise change between the 250μm and 500μm mesh size samples, being relatively constant in the <500μm and >500μm categories, with diversity higher in the former. Higher proportions of species in the <500μm categories showed evidence of spatial clustering than in the >500μm categories. This suggests a fractal structure within but not between the <500μm and >500μm body size categories, which apparently is not driven by differences in sediment structure. The biology of marine metazoan benthos does not scale continuously across the full range of taxa and body size as has been recently suggested, but may do so for individual taxa and restricted size ranges.

Ecological outcomes and popular perceptions of urban restored forests in Rio de Janeiro, Brazil

SUMMARYEcological restoration is suggested as a tool to mitigate environmental problems caused by urbanization, but its utility may be hampered by conflict between ecological design and neighbouring communities’ needs. We explore this issue by comparing vegetation diversity and structure in a 21-year-old urban reforestation project in Rio de Janeiro city, Brazil, with a nearby reference forest, and we assessed popular perceptions about the project. Overall, density and basal area of canopy trees in the restoration plantation reached 73% and 46%, respectively, of the values found in the reference forest, but ground cover by exotic grasses was substantially higher in the planted forest. Rarefied species richness was similarly high in the plantation forest (59 species) and in the remnant forest (69 species), but species composition was markedly different. The human legacy on restoration diminished with time, reflected in the higher proportion of species and individuals of late-successional, native and not-planted species in the seedling community of the plantation forest. While community perceptions of reforestation were positive and both use and non-use values were reported, interviewees reported little involvement in the development of the project, which could have contributed to synergies between ecological and social outcomes.

Ant and termite communities in isolated and continuous forest fragments in Singapore

The conservation of tropical rainforest biodiversity is a pressing issue, due to the rapid rate of deforestation. Secondary forests may provide a useful alternative to old growth forests, as they often contain a substantial proportion of the original biodiversity. In this study, we investigate species richness, density and composition of ants and termites in six forest sites in Singapore, each differing in habitat isolation and land-use history. The six sites include an old growth forest, a selectively logged old growth forest, and four secondary forests: either located on abandoned agricultural lands or in abandoned villages, and either isolated or adjacent to old growth forests. We found that the old growth forest had significantly higher species density of ants and termites than any other site. Rarefaction curves showed that ant and termite species richness were highest in the old growth forest followed by the selectively logged forest albeit these results were not significantly different from other sites. Ant species composition changed along a gradient of fragment isolation. Termite community composition in the old growth forest shared a higher proportion of species with the adjacent secondary forest, than with the selectively logged old growth forest, suggesting that the species pool of adjacent habitats is important for species re-colonisation of regenerating habitats. Our results suggest, albeit without replications, that secondary forests differ in conservation value and that disturbed habitats in continuous forest fragments recover more rapidly than isolated ones. Further, we emphasise the importance of old growth forest fragments within man-made ecosystems as sources of original biodiversity.

Estrutura e distribuição espacial da vegetação da Caatinga na Estação Ecológica do Seridó, RN

Este trabalho descreve a estrutura e o padrão de distribuição espacial das espécies do estrato arbóreo-arbustivo na Caatinga da Estação Ecológica do Seridó, no Município de Serra Negra do Norte, RN. Foram amostrados os indivíduos com diâmetro ao nível do solo ≥ 3 cm e altura total ≥ 1 m, presentes em 30 parcelas de 200 m2. O padrão de distribuição espacial foi determinado pelo índice de Payandeh. Registraram-se 2.448 indivíduos, distribuídos em 22 espécies, 20 gêneros e 12 famílias. A densidade foi de 4.080 indivíduos ha-1 e área basal de 17,50 m2 ha-1, enquanto a altura e o diâmetro médios atingiram 2,45 m e 6,80 cm, respectivamente. As famílias com maior número de espécies foram Fabaceae e Euphorbiaceae, com destaque em número de indivíduos para Euphorbiaceae, Fabaceae e Apocynaceae. Poincianella pyramidalis, Aspidosperma pyrifolium e Croton blanchetianus foram as espécies mais importantes, respondendo juntas pelo maior número de indivíduos, área basal e valor de importância. A área estudada apresenta pouca evidência de perturbação antrópica, com estrutura semelhante a outras áreas protegidas na Caatinga do Seridó e com maior proporção de espécies com distribuição agregada ou com tendência à agregação, revelando que as maiores populações formam pequenos agrupamentos.

Saving rainforests in the South Pacific: challenges in ex situ conservation

Rainforests in the South Pacific hold a considerable amount of plant diversity, with rates of species endemism &gt;80% in some countries. This diversity is rapidly disappearing under pressure from logging, clearing for agriculture or mining, introduced pests and diseases and other anthropogenic sources. Ex situ conservation techniques offer a means to limit the loss of plant diversity. Seed banking is considered the most efficient and cost effective of these techniques but is applicable only to seed capable of tolerating desiccation and cold storage. Data on the degree of tolerance of these conditions was lacking for more than half of the 1503 South Pacific rainforest genera examined for this review. Of the 710 genera for which data were available, the storage behaviour of 324 was based on an assessment of only one or two species, although 76% of those genera contained at least 10 species. Many of the unstudied or poorly studied genera are shared across several South Pacific nations, providing an excellent opportunity for collaboration on future ex situ research and conservation. Of the 386 genera for which three or more species have been studied, 343 have a very high proportion of species (&gt;95% of those tested) that are suitable for seed banking. Seed banking could therefore provide a suitable means for preserving a large proportion of the rainforest flora before it becomes extinct in the wild. Alternatives for preserving species that are not suitable for seed banking are also discussed.