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The difficulty in obtaining commercial fertilizers by smallholder farmers in sub-Saharan Africa makes it very important to optimize the use of local organic resources. In VilanKulo, Mozambique, a study was carried out on okra (Abelmoschus esculentus) over two growing seasons. The soil was a haplic, loamy-sand textured Lixisol. As organic amendments, bat guano and biochar were used. Bat guano is a phosphorus (P)-rich and low-carbon (C)/nitrogen (N)-ratio material from natural deposits on a cave floor. Biochar is a C-rich material prepared via an artisanal process using forest residues as a feedstock. Bat guano was applied at two rates (5 and 10 t ha−1) just before sowing. It was also applied at the same rates one month before sowing. Biochar was used at two rates (5 and 10 t ha−1) applied at sowing. Biochar and guano were mixed at the rates of 1 and 4 t ha−1 and 2 and 8 t ha−1, respectively, and applied at sowing. The experiment also used a non-fertilized control. Field trials were arranged in a completely randomized design with three replicates. The treatments that received high rates of guano tended to show significantly higher fruit yields (>10 t ha−1 as the two-year average) in comparison with the control, which showed the lowest average okra fruit yield (6.21 t ha−1). In the guano treatments, the apparent recovery by okra of some important nutrients, such as N, was greater than the amount of the nutrient contained in the guano itself. This result, together with many others related to the tissue nutrient concentration, soil properties and residual fertilizing value in guano plots, indicated a strong mineralization of guano during the growing season. This was probably due to its low C/N ratio and favourable environmental conditions for the mineralization process. The result also suggests some kind of manuring effect, i.e., a fertilizing effect of guano beyond what can be explained by the nutrient supply. The use of biochar increased the total organic C in the soil and cation exchange capacity (CEC) compared with the control but did not affect the variables related to plant performance. Overall, the results showed that farmers can benefit from the use of guano in the short term because it releases nutrients, while with the use of biochar, the benefits can arise in the long term by improving the soil properties.

Background and aims – Understanding the spatial patterns and associations of tree species with their conspecific and heterospecific neighbours is critical for sustainable management of their stands. This study assessed the intra- and interspecific spatial structure of six life stages in Afzelia africana, a keystone multipurpose and endangered tree species in a tropical savanna of Benin.Material and methods – Three plots of 4 ha each were demarcated on three sites along a conservation gradient (hunting zone – core conservation zone). Individuals of A. africana (irrespective of their diameter at breast height) and heterospecific trees (dbh ≥ 5 cm) were mapped. Tree spatial patterns and associations were determined using univariate and bivariate pair correlation functions. The distance to the nearest neighbour was further used to assess tree-to-tree distance.Key results – We found variable spatial patterns across sites. In the core zone where wildlife density is high, most life stages had a random distribution. In contrast, in the hunting zone where wildlife density is low, the species spatial distribution changed from a predominantly aggregative pattern during early stages to a less aggregative or random spatial pattern for very large adults. Most pairs of life stages showed neutral associations, except for small and large adults, which had positive association between themselves on two sites. We also found that A. africana tree spatial distribution was unrelated to heterospecific trees.Conclusion – We suggest that bush fire, seed dispersion, predation, and local environment would have contributed to the observed patterns.

To improve reproductive success and maximize offspring survival, bird parents have to deal with the threat of nest predation while caring for nestlings, which necessarily involves their presence near the nest. On the other hand, predators may use cues to find nests, such as conspicuousness of the nest, nestlings, or parents. Although conspicuousness may confer advantages for males and females in some contexts (e.g., individual quality and mate choice), it may also confer survival costs for individuals or their offspring, especially when predators are visually oriented. In this study, we carried out a field experiment to test if visual cues attract predators to nests and impose a higher risk to eggs. By using painted styrofoam balls and artificial nests baited with Quail eggs, we asked if the presence of conspicuous or cryptic visual cues increased the nest predation risk. Based on our experimental results, we rejected the hypothesis that visual cues increase nest predation. The presence of visual cues in the nest did not impose additional risks to eggs. This may be explained by particularities of the study area, such as the possibility that predators at our site are mostly olfactory oriented. Furthermore, additional factors associated with parental care (e.g., parental movements around nests), which were not evaluated here, may have a greater impact on birds’ nest predation. Our study is consistent with previous studies that found no effects of individual factors (e.g., visual cues) on nest predation, emphasizing the complexity of these events.

Made available in DSpace on 2022-04-28T19:46:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Fire and herbivory are major drivers in tropical savanna ecosystems and they selected a flora composed of species able to cope with recurrent aboveground biomass removal. Renewal of the herbaceous stratum is made possible by resprouting, mostly through a belowground bud bank. Evaluating the impacts of disturbances on the bud bank can assist in predicting post-disturbance responses and system resilience. In a semi-arid savanna, we aimed to verify whether lower fire frequency, fire and herbivory exclusion could affect belowground bud bank and organs diversity and consequently, the resprouting potential. Lower fire frequency or suppression and absence of herbivory were expected to reduce the bud bank density, which was confirmed by our results. If the fire is suppressed or fire frequency is reduced, the total, graminoid and the shrub bud bank decreased, whereas herbivory exclusion resulted in total and a forb bud bank of lower densities. Belowground buds were identified in non-woody and woody rhizomes, stolons, root crowns, and bulbs or corms. Despite having bud banks of lower density, disturbance exclusion promoted belowground biomass accumulation. Our results indicated the importance of maintaining the endogenous disturbances to the preservation of the belowground community and regeneration strategy, guaranteeing resilience in semi-arid savanna communities. Instituto de Biociências Universidade Estadual Paulista (UNESP) Unit for Environmental Sciences and Management North-West University Instituto de Biociências Universidade Estadual Paulista (UNESP)

Macauba (Acrocomia aculeata) is a palm tree with a high potential for plant-based raw material production, particularly bioenergy production; it is one of the most promising species for cultivation on marginal lands. This study aimed to determine the distribution of A. aculeata species worldwide and verify the Koppen–Geiger climatic classifications of its locations. Research on the global occurrence of A. aculeata was conducted to characterize the geographic dispersal of macauba. Based on the distribution points of the species, the Koppen–Geiger classification was determined for each occurrence point. Subsequently, a map was created that showed the regions with potential for the introduction of macauba based on the climatic data compiled. Macauba is distributed throughout the American continents, with the highest occurrence rates in Latin America (followed by those in North America and finally Central America). Particularly, Brazil and Mexico exhibit the highest occurrence rates. According to the distribution, the Koppen–Geiger climatic classification determined the predominance of macauba in the savanna climate. Some countries located in Central Africa, Southern Asia, and Northern Australia showed the potential to introduce macauba as a bioenergetic source.

The success of the galling insects sharing the same microhabitat depends both on the synchrony of their life cycles with the leaf flushing of the super-host plant and to the asynchrony among their life cycles. The asynchrony of the multivoltine life cycles of Lopesia spp. (Diptera—Cecidomyiidae) is favored by the constant leaf flushing in M. gemmulata, and favors the non-overlapping of gall induction periods. Peculiarly, the univoltine life cycle of the galling Lepidoptera on its stem galls is synchronized to the availability of mature host leaves during the rainy season, which is important for the water potential in host stem branches. The abundance of the Lopesia gall morphotypes follow the phenology of M. gemmulata, which obeys the seasonal pattern of water availability in the neotropical savanna climate.

Tree hollows are a critical resource for many arboreal vertebrates, including many threatened species. In northern Australia’s vast tropical savannas, arboreal mammals are of particular conservation concern, as many have exhibited rapid population declines in recent decades. To understand the extent to which arboreal vertebrates compete for tree hollows in these savannas, we used motion-activated cameras to estimate rates of hollow visitation (i.e. individuals seen at the hollow entrance) and hollow use (i.e. individuals seen entering or exiting a hollow) by all vertebrate species at 29 hollows over a nine-month wet season period in the tropical savanna of Melville Island, Australia. We assessed the frequency of interactions between vertebrate species at the tree hollows. We recorded 21 vertebrate species visiting hollows, with larger hollows most frequently visited: 84% with entrance diameter > 10 cm. Larger-bodied mammal species were more likely to use larger hollows, in larger trees, at greater heights. However, smaller-bodies species also visited and used large hollows. The brush-tailed rabbit-rat (Conilurus penicillatus) used relatively shallow hollows close to the ground, and these hollows were most frequently visited by monitors (Varanus spp.) and snakes. This arboreal rodent has declined severely in recent decades, most likely due to predation by feral cats, and it is noteworthy that their hollow selection behaviour may be associated with increased predation risk. Our study highlights the importance of large tree hollows for a range of taxa in the tropical savannas of northern Australia and the potential impact of reductions in the density of large hollows on hollow-dependent species. Frequent, intense fires are a threat to large hollow-bearing trees, with appropriate fire management needed to conserve this resource and help to stem mammal declines.

A warmer climate has caused more extreme climate events like the heatwave or extreme precipitation, which has led to a large number of lives and economic losses. In this study, we adopt historical daily precipitation from rainfall estimates on a gridded network (REGEN) and future daily projections from 10 general circulation models (GCMs) to analyze the potential risks of extreme precipitation due to changes in the magnitude and frequency. We calculate the 10-year and 100-year return levels by fitting the partial duration series (PDS) data with the generalized Pareto (GP) distribution. The potential risks are quantified in two terms: by the ratio of the magnitude to the threshold and by the exceedance frequency comparing to the theoretical value. The results show that in the future, about 46% of the world may suffer from mid or high risk of change in extreme precipitation. Most regions show higher risk due to the increased frequency of extreme precipitation events under the RCP8.5 scenario. The high risk of humid regions mainly appears under the RCP8.5 scenario and is mainly driven by frequency change, while that of arid regions appears under both the scenarios and is driven by both the frequency and magnitude change. The tropical rainforest climate areas of South America (SA (N)), the tropical savanna or tropical wet monsoon and tropical dry areas of South Asia (SA), and the subarctic climate areas of Northern Asia (NOA) may suffer more risks from the view of both magnitude and frequency changes of extreme precipitation.

The cultural and ecological importance of fork-tailed catfish, Neoarius graeffei, in northern Australia is linked to its energy stores, or how fat fish are. Water resource development that alters river flow has the potential to impact the energy stores of fork-tailed catfish. We investigated the influence of flow and habitat on the energy reserves of fork-tailed catfish during the dry season in an intermittent wet–dry tropical river using data collected in three years with different flow volumes from a variety of habitats, i.e. different mesohabitats (tributary, main-channel) and pool sizes. Julian day was included to describe seasonal trends. We used mesohabitat and pool size to reveal where fork-tailed catfish had the most energy reserves and flow-year and Julian day to reveal when reserves were greatest. Body condition and the quantity of intramuscular and coelomic fat were used to describe energy reserves. Predictive models created for each metric revealed that fork-tailed catfish body condition and intramuscular fat were greater in years following moderate to high wet-season flow, smallest in a year following very low flows and decreased as the dry season progressed. Coelomic and intramuscular fat of fork-tailed catfish was also lower in smaller pools. There was no association between mesohabitat and energy store. These when and where hydro-ecological patterns highlight the importance of wet season flows and groundwater-fed refuge pools for fork-tailed catfish energetics in this wet–dry tropical river. Intermittent rivers flowing through wet–dry tropical savanna habitats are under increasing threat globally and the results of the present study illustrate how flow variation may impact on biota and influence their continued survival and functional roles.

In environmental management, land cover change is a crucial aspect. The area of tropical savanna environments is vulnerable to land degradation. This study aimed to rapidly detect land cover changes in a tropical savanna environment based on remote sensing data. Conditional change detection was performed using the Change Vector Analysis (CVA) with input parameters such as the Enhanced Vegetation Index (EVI) and Normalized Difference Soil Index (NDSI). The results showed that during the period 2015 to 2019, changes were detected in the Moyo watershed every year. From 2015 to 2016, the Moyo River Basin was dominated by changes with a change magnitude of less than 0.088, which was 63% of the Moyo River Basin area. From 2016 to 2017, the changes were dominated by the change magnitude value of 0.063, which was 58.6% of the Moyo River Basin area. From 2017 to 2018, changes were dominated by the change magnitude value of 0.084 of 55.26% of the Moyo watershed area. From 2018 to 2019, the change was dominated by the change magnitude value of 0.057, which was 47.57% of the Moyo watershed area. The direction of land cover change was dominated by Q2 in 2016, Q4 in 2017 and 2018, and Q2 and Q4 in 2019. These changes generally occurred in the Moyo watershed middle and downstream parts, which are grasslands. The use of the Conditional Change Vector Analysis (CCVA) approach in a tropical savanna environment can detect changes and the direction of change with an accuracy of about 70%.

Fire has a long history in Australia and is a key driver of vegetation dynamics in the tropical savanna ecosystems that cover one quarter of the country. Fire reconstructions are required to understand ecosystem dynamics over the long term but these data are lacking for the extensive savannas of northern Australia. This paper presents a multiproxy palaeofire record for Marura sinkhole in eastern Arnhem Land, Northern Territory, Australia. The record is constructed by combining optical methods (counts and morphology of macroscopic and microscopic charcoal particles) and chemical methods (quantification of abundance and stable isotope composition of pyrogenic carbon by hydrogen pyrolysis). This novel combination of measurements enables the generation of a record of relative fire intensity to investigate the interplay between natural and anthropogenic influences. The Marura palaeofire record comprises three main phases: 4600–2800 cal BP, 2800–900 cal BP and 900 cal BP to present. Highest fire incidence occurs at ~4600–4000 cal BP, coinciding with regional records of high effective precipitation, and all fire proxies decline from that time to the present. 2800–900 cal BP is characterised by variable fire intensities and aligns with archaeological evidence of occupation at nearby Blue Mud Bay. All fire proxies decline significantly after 900 cal BP. The combination of charcoal and pyrogenic carbon measures is a promising proxy for relative fire intensity in sedimentary records and a useful tool for investigating potential anthropogenic fire regimes.

Long-term monitoring of bird communities over time can provide important data for management, and the adaptation of that management over time. We examined data from bird surveys across 37 sites sampled in five different years from 2009 to 2017 in a 56,000-ha tropical savanna conservation reserve, in northern Queensland. Because of the limitations of the survey method and the lack of environmental data for sites, we examined broad patterns in the abundance of small- and large-bodied birds, abundance of Noisy Miners Manorina melanocephala, land type, survey year, and time since last fire. There was some variation in bird species richness and abundance across the land types, years sampled and Noisy Miner abundance; however, the clearest pattern was decreasing numbers of small-bodied birds and increasing Noisy Miner abundance, and an association between time since fire (i.e. 5 years), Noisy Miner abundance and diversity in other birds. The apparent and potentially compounding interaction of Noisy Miners and fire could be an emerging problem. Future fire management needs to be embedded in a program of targeted question-driven monitoring and adaptive management, to provide more assured approaches to prescribed burning that enhances bird conservation.

PREMISE Belowground functional traits play a significant role in determining plant water-use strategies and plant performance, but we lack data on root traits across communities, particularly in the tropical savanna biome, where vegetation dynamics are hypothesized to be strongly driven by tree-grass functional differences in water use. METHODS We grew seedlings of 21 tree and 18 grass species (N = 5 individuals per species) from the southern African savanna biome under greenhouse conditions and collected fine-root segments from plants for histological analysis. We identified and measured xylem vessels in 539 individual root cross sections. We then quantified six root vascular anatomy traits and tested them for phylogenetic signals and tree-grass differences in trait values associated with vessel size, number, and hydraulic conductivity. RESULTS Grass roots had larger root xylem vessels than trees, a higher proportion of their root cross-sectional area comprised vessels, and they had higher estimated axial conductivities than trees, while trees had a higher number of vessels per root cross-sectional area than grasses did. We found evidence of associations between trait values and phylogenetic relatedness in most of these traits across tree species, but not grasses. CONCLUSIONS Our findings support the hypothesis that grass roots have higher water transport capacity than tree roots in terms of maximum axial conductivity, consistent with the observation that grasses are more "aggressive" water users than trees under conditions of high soil moisture availability. Our study identifies root functional traits that may drive differential responses of trees and grasses to soil moisture availability.

International audience; Plants continue to lose water from their leaves even after complete stomatal closure. Although this minimum conductance (g(leaf-res)) has substantial impacts on strategies of water use and conservation, little is known about the potential drivers underlying the variability of this trait across species. We thus untangled the relative contribution of water leaks from the cuticle and stomata in order to investigate how the variability in leaf morphological and anatomical traits is related to the variation ing(leaf-res)and carbon assimilation capacity across 30 diverse species from the Brazilian Cerrado. In addition to cuticle permeance, water leaks from stomata had a significant impact ong(leaf-res). The differential pattern of stomata distribution in the epidermis was a key factor driving this variation, suggesting the existence of a trade-off between carbon assimilation and water loss throughg(leaf-res). For instance, higherg(leaf-res), observed in fast-growing species, was associated with the investment in small and numerous stomata, which allowed higher carbon assimilation rates but also increased water leaks, with negative impacts on leaf survival under drought. Variation in cuticle structural properties was not linked tog(leaf-res). Our results therefore suggest the existence of a trade-off between carbon assimilation efficiency and dehydration tolerance at foliar level.

We characterized soil bacterial and archaeal communities under native Cerrado vegetation and their responses to increases in soil pH. The experimental area was subjected to lime additions for eight consecutive years, followed by an 11-year interval and an additional lime application. We collected soil samples in the rainy and dry seasons of 2017 (representing the 11-year interval from the last liming) and 2018 (representing short-term effects, 4 and 9 months after we resumed the liming). We studied the microbial communities of soil samples from control and treatment plots (liming) through 16S rRNA gene sequencing. We found that microbial community profiles differed by treatment and sampling period, suggesting long-term effects of liming and the strong influence of Cerrado's seasonal dynamics. Samples from liming treatment had a higher bacterial diversity than the control treatment, while the archaeal community showed the opposite response with lower diversity. Different from diversity estimators, enzyme-encoding genes for C, N, and S metabolic pathways showed a reduction in abundance in the liming treatment. The effects of liming on the soil microbial community under Cerrado vegetation are long-lasting. Despite the increase in diversity, the predicted functional profiles suggested a potential reduction on soil multifunctionality.

Tree cavities are important denning sites for many arboreal mammals. Knowledge of cavity requirements of individual species, as well as potential den overlap among species, is integral to their conservation. In Australia’s tropical savannas, development of tree cavities is enhanced by high termite activity, and, conversely, reduced by frequent fires. However, it is poorly understood how the availability of tree cavities in the tropical savannas impacts tree cavity use and selection by cavity-dependent fauna. There has been a severe decline among arboreal mammal species in northern Australia over recent decades. Investigation of their cavity requirements may illuminate why these species have declined drastically in some areas but are persisting in others. Here we examined this issue in three species of arboreal mammals (Trichosurus vulpecula, Mesembriomys gouldii, Conilurus penicillatus) on Melville Island, northern Australia. We radiotracked individuals to their den sites to evaluate whether the species differ in their den tree and tree-cavity selection. The strongest influence on den tree selection was the presence of large cavities (> 10 cm entrance diameter), with all three species using larger cavities most frequently. Conilurus penicillatus, the smallest species, differed the most from the other species: it frequently was found in smaller, dead trees and its den sites were closer to the ground, including in hollow logs. The two larger species had broader den tree use, using larger live trees and dens higher up in the canopy. Dens of C. penicillatus are likely to be more susceptible to predation and destruction by high-intensity savanna fires. This may have contributed to this species’ rapid decline, both on Melville Island and on the mainland. However, the apparent preference for larger tree cavities by all three arboreal species is concerning due to the limited availability of large trees across Australian savannas, which are subject to frequent, high-intensity fires.

The magnitude of the terrestrial carbon (C) sink may be overestimated globally due to the difficulty of accounting for all C losses across heterogeneous landscapes. More complete assessments of net landscape C balances (NLCB) are needed that integrate both emissions by fire and transfer to aquatic systems, two key loss pathways of terrestrial C. These pathways can be particularly significant in the wet-dry tropics, where fire plays a fundamental part in ecosystems and where intense rainfall and seasonal flooding can result in considerable aquatic C export (sigma F-aq). Here, we determined the NLCB of a lowland catchment (similar to 140 km(2)) in tropical Australia over 2 years by evaluating net terrestrial productivity (NEP), fire-related C emissions and sigma F-aq (comprising both downstream transport and gaseous evasion) for the two main landscape components, that is, savanna woodland and seasonal wetlands. We found that the catchment was a large C sink (NLCB 334 Mg C km(-2) year(-1)), and that savanna and wetland areas contributed 84% and 16% to this sink, respectively. Annually, fire emissions (-56 Mg C km(-2) year(-1)) and sigma F-aq (-28 Mg C km(-2) year(-1)) reduced NEP by 13% and 7%, respectively. Savanna burning shifted the catchment to a net C source for several months during the dry season, while sigma F-aq significantly offset NEP during the wet season, with a disproportionate contribution by single major monsoonal events-up to 39% of annual sigma F-aq was exported in one event. We hypothesize that wetter and hotter conditions in the wet-dry tropics in the future will increase sigma F-aq and fire emissions, potentially further reducing the current C sink in the region. More long-term studies are needed to upscale this first NLCB estimate to less productive, yet hydrologically dynamic regions of the wet-dry tropics where our result indicating a significant C sink may not hold.

Made available in DSpace on 2021-06-25T12:26:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) Rupert Barneby Award of The New York Botanical Garden Biologia Vegetal post-graduate program at UNICAMP UNESP-Botucatu Instituto de Pesquisas JBRJ UFOP UFG Eriosema comprises c. 150 species and has a pantropical distribution and two centres of diversity, Africa and America. The species occur in tropical savannas and grasslands, including the cerrado in Brazil. They have adapted to these environments by developing specialized underground organs, and an abundance of trichomes. Here we present the first comprehensive molecular phylogenetic analysis of Eriosema, including species from its entire distribution range and generating 391 new DNA sequences. We sampled 140 species from nine genera of Cajaninae, of which 94 (60% of the genus) were Eriosema. Our analyses were based on the nuclear ITS and plastid rp132 and trnQ regions, and used maximum likelihood and Bayesian phylogenetic analyses of individual and combined data sets. In all analyses, Eriosema was resolved as monophyletic, but its interspecific relationships are not well resolved. Rhynchosia is not monophyletic, and some African Rhynchosia spp. emerged together as sister to Eriosema. Our study supports the monophyly of Adenodolichos, Dunbaria, Flemingia and Cajanus, but Chrysoscias and Bolusafra formed a dade that is sister to a group of Rhynchosia spp. Paracalyx was resolved as paraphyletic and nested among African Rhynchosia spp. Divergence time analysis suggested that the Eriosema lineages diverged 6.5-10.7 Mya. Two major lineages have diversified in Eriosema, one including most of the African species (4.41-6.68 Mya), the other mainly composed of the South American cerrado species (3.56-5.78 Mya). These results revealed that Eriosema is a recent and tropical savanna-adapted group, and its diversification occurred in the late Miocene in parallel with the expansion of C-4 grasslands. Univ Estadual Campinas, Inst Biol, Dept Biol Vegetal, Programa Posgrad Biol Vegetal, BR-13083862 Campinas, SP, Brazil Univ Copenhagen, Dept Geosci & Nat Resource Management, Rolighedsvej 23, DK-1958 Frederiksberg C, Denmark Smithsonian Inst NMNH, Dept Bot, US Natl Herbarium US, MRC 166,10th & Constitut Ave, Washington, DC 20560 USA Univ Estadual Paulista, Inst Biociencias, Programa Posgrad Ciencias Biol Bot, Dept Bot, BR-18618000 Botucatu, SP, Brazil Royal Bot Gardens, Comparat Plant & Fungal Biol Dept, Richmond TW9 3AB, Surrey, England DIPEQ, Inst Pesquisas Jardim Bot Rio de Janeiro, Rua Pacheco Leao 915, BR-22460030 Rio De Janeiro, RJ, Brazil Univ Fed Goias, Inst Ciencias Biol, Dept Bot, CP 131, BR-74001970 Goiania, Go, Brazil Univ Cape Town, Dept Biol Sci, Bolus Herbarium, ZA-105 Rondebosch, South Africa Univ Estadual Paulista, Inst Biociencias, Programa Posgrad Ciencias Biol Bot, Dept Bot, BR-18618000 Botucatu, SP, Brazil FAPESP: 2015/13386-0 FAPESP: 09/53002-5 CNPq: 400567/2016-4 FAPEMIG: APQ-02323-12 CAPES: 88887.373155/201900 FAPERJ: 203.007/2017 CNPq: 312766/2009-2 CNPq: 563550/2010-4 CNPq: 141628/2016-2

Global change may induce changes in savanna and forest distributions, but the dynamics of these changes remain unclear. Classical biome theory suggests that climate is predictive of biome distributions, such that shifts will be continuous and reversible. This view, however, cannot explain the overlap in the climatic ranges of tropical biomes, which some argue may result from fire-vegetation feedbacks, maintaining savanna and forest as bistable states. Under this view, biome shifts are argued to be discontinuous and irreversible. Mean-field bistable models, however, are also limited, as they cannot reproduce the spatial aggregation of biomes. Here we suggest that both models ignore spatial processes, such as dispersal, which may be important when savanna and forest abut. We examine the contributions of dispersal to determining biome distributions using a 2D reaction-diffusion model, comparing results qualitatively to empirical savanna and forest distributions in sub-Saharan Africa. We find that the diffusion model resolves both the aforementioned limitations of biome models. First, local dispersive spatial interactions, with an underlying precipitation gradient, can reproduce the spatial aggregation of biomes with a stable savanna-forest boundary. Second, the boundary is determined not only by the amount of precipitation but also by the geometrical shape of the precipitation contours. These geometrical effects arise from continental-scale source-sink dynamics, which reproduce the mismatch between biome and climate. Dynamically, the spatial model predicts that dispersal may increase the resilience of tropical biome in response to global change: the boundary continuously tracks climate, recovering following disturbances, unless the remnant biome patches are too small.

Plant disease is defined as a malfunction or dysfunction of plant physiological normal activities with addition of behaviousristic or morphological changes of normal cell shape and size. Surveillance is an active or passive way of collecting, analyzing, interpreting information on disease occurrence in specified area which is further utilizable to control the effectiveness of the specified disease. Rural Entrepreneurship Awareness Development Yojana (READY) is a real time based experiential learning programme with combination of field based practical training and business application in agriculture sciences. Centurion University of Technology and Management (CUTM) every year organized READY programme under the curriculum of agriculture which helps in one direction to for in hand training of new agriculturist, on the other hand it transferred new modern scientific skills to the poor grass hood level farmers. This programme revealed with some remarkable data’s of some severe pest-disease infestation in a broader spectrum. Different biotic factors will considered to be the most influential factor among them. Major diseases and pests include rice blast, northern corn blight, black rot of cole crops, chilli leaf curl virus etc. The different types of pests observed are sucking pests, fruit borers, leaf rollers, leaf eating caterpillars etc. and their incidence level ranged between 25-60%. Crucial epidemiological factors like moderate temperature (30-35° C), high humidity (85-90%) and scattered rainfall (120-150 mm). The present investigation through real time surveillance and monitoring, we are trying to focus major biotic stresses, their behaviouristic nature and their conventional management strategy which applied for long time.

Carpenter’s Gap 1 is a large rockshelter located within the Kimberley region of northwestern Australia. The site provides valuable archives of late Quaternary palaeoecological information within an area known for a lack of deposits preserving long-term continuous botanical records. Previous studies of the macrobotanic, phytolith and wood charcoal records from Carpenter’s Gap 1 are in general agreement about changes in broad vegetation patterns over time but differ in the time scales used, in the representation of some species, and in the interpretation of changes – particularly on the degree to which the variations in the record represent cultural activities. An examination of palynology (the transport, deposition and preservation of pollen within the rockshelter environment) provides more detail to the vegetation patterns identified in these previous studies. In addition, because the pollen most likely reflects the vegetation of the site’s surrounds over time rather than plants introduced into the shelter by people, interpretation can be more confidently linked to environmental change, and by inference climatic conditions. The pollen data reveal pre-glacial mixed wooded vegetation. From the beginning of the Holocene, tree loss occurred in a transition from monsoonal forest to thicket and eucalypt forest to woodland. Vegetation transition around the mid Holocene suggests a shift in climate, becoming drier and more variable towards and into the late Holocene. The role of fire in the establishment of vegetation communities remains under investigation.

A survey to investigate the occurrence of cassava anthracnose disease (CAD) and distribution of Colletotrichum spp. in cassava plantations in different eco-zones of the Reconcavo Region in Bahia, Brazil, investigated during the rainy season of 2014. A total of 50 cassava fields distributed among 18 municipalities were visited and intensity of anthracnose evaluated. The highest disease incidence (DI) (83.3%) was in samples collected in São Félix, and the lowest (34.4%), in Varzedo. Municipalities that presented the highest values for DI were located within the ‘Af’ Köppen–Geiger eco-zone, also presenting the highest values for the estimated McKinney disease index. Based on previous studies of multilocus phylogeny, seven different species of Colletotrichum were identified (Colletotrichum fructicola, Colletotrichum tropicale, Colletotrichum gloeosporioides s.s, Colletotrichum theobromicola, Colletotrichum siamense, Colletotrichum brevisporum and Colletotrichum plurivorum) and a new approach based on ERIC-PCR was used aiming to group the 82 isolates according to these findings. The highest percentage of genetic variance (> 78%) was among isolates within fields. Based on the survey and genetic analysis, C. fructicola is probably the main causal agent of cassava anthracnose in the Recôncavo Region, since this species was present with highest incidence in all eco-zones, 47.61, 42.86 and 57.14% for Af (tropical rainforest climate), As (tropical dry savanna climate) and Aw (tropical wet savanna climate), respectively. This study is the first report of C. fructicola lineages as the most likely pathogen causing anthracnose disease of cassava in Brazil, and these findings may be used to guide the selection of resistant varieties.

The aim of this study was to evaluate the losses that occur in the sugarcane crop during the harvesting, based on the performance of two harvester models operated at different displacement speeds. The variety harvested was CTC4, with total productivity of 95.0 Mg ha-1. The experimental design was completely randomized in a 2 x 3 factorial scheme with five replications. The treatments consisted of two harvester models (John Deere 3520 and John Deere CH570), operated in three different displacement speeds (3.0 km h-1, 4.0 km h-1 and 5.0 km h-1) in sugarcane harvesting. The quality indicators that assessed after sugarcane harvesting were the following loss types: stump cane, whole cane, tip cane, loose piece cane, shrapnel cane and total cane loss in Mg ha-1. The increase in displacement speed resulted in lower total losses in sugarcane harvesting. The 3520 harvester was superior to the CH570 at the highest speed tested. The reduction of sugarcane harvesting loss indexes was proportional to the increase of the displacement speeds for the parameters such as stump cane, whole cane, tip cane, loose piece cane and total loss cane for 3520 harvester and stump cane, whole cane and total loss cane for CH570 harvester, showing strong negative correlations (> 0.85).

Phase change materials can be applied into building framework to reduce energy and fossil fuel consumption as well as to make the building sector more sustainable. In this research, it is hypothesized that a group of PCMs in the narrow range can be used for the whole tropical savanna climate according to Koppen-Geiger climate classification. Eight representative cities (Bamako, Bangalore, Bangkok, Brasilia, Dar es Salaam, Kolkata, Maputo and Surabaya) from seven different countries (Mali, Thailand, Brazil, Tanzania, India, Mozambique and Indonesia) were chosen in accordance with their demographical and economical state. Numerical simulations were performed in DesignBuilder software to carry out detailed investigation about thermal behavior and energy performance of a residential building integrated with eleven different PCMs (PCM21-PCM31). In addition, the impact of PCM thickness, its location in the wall (external, middle, and internal) and different surface area were assessed. Results of thermal performance during a summer day revealed that temperature fluctuations in PCM integrated building dropped by up to 2.76 °C even when the HVAC system was switched off. From energy analysis, the hypothesis of this research was confirmed, and the narrow range of PCMs (PCM25-PCM29) were found to be optimum for this climate zone. Considerable energy savings and energy consumption reduction up to 68.63% was obtained. Furthermore, for constant volume, the thinner PCM layer with greater surface area exhibited superior performance in terms of energy savings. Hence, the incorporation of PCM in buildings located in a tropical savanna climate is feasible.

Tropical savanna and dry forest in Indonesia are an important type of ecosystem that supports various endemic wildlife of Indonesia including savannas at Padar and Komodo Islands which is home to the Komodo (Varanus komodoensis). The Komodo dragon is considered as “Vulnerable” by the International Union for Conservation of Nature. Studies with regards to the Komodo dragons’ habitats are scarce, considering that these types of habitats are significant to support Komodo’s existence, but yet are also very prone to conversion and disturbances. This paper elaborates the results of ecological study on the tropical savanna forest in Komodo National Park as habitat for the Komodo dragon. Vegetation sampling was conducted using nested plots 20 x 20 m, 10 x 10 m, 5 x 5 m and 2 x 2 m spread across the sampling sites. Data was analysed using PRIMER software which includes cluster analysis, analysis of similarity (ANOSIM) and similarity percentage (SIMPER). As many as 17 plant species which belongs to 11 families were identified in the sampling sites. These consist of six trees habitus, six shrubs, four grasses and one palm. Asteraceae, Fabaceae and Poaceae were the plant families which has high number of species. The result of cluster analysis shows that the similarity level of the two groups (Komodo and Padar) based on the results of cluster analysis is 60%. This result infers that there are similarities in terms of species composition in savanna on Komodo and Padar Island, however, each savanna still has its own species characteristics. This is confirmed by the ANOSIM test. The ANOSIM test results show the Global R value of 0.6.With the looming challenges from invasive alien plant species (IAPS), the Komodo Island’s savanna has double threats to overcome. Hence conservation of the remaining savanna ecosystem is important

Australian mammals have exhibited exceptionally high rates of decline since European settlement 230 years ago with much focus on small mammals in northern tropical savannas. In these systems, little scientific attention has been given to the suite of grazing macropods, family Macropodidae, (common wallaroo (Osphranter robustus), antilopine wallaroo (O. antilopinus) and agile wallaby (Notamacropus agilis)). These species may be impacted by feral herbivores and contemporary fire regimes, two threats linked to small mammal declines. A multi‐scale approach using aerial surveys, road surveys and camera trapping was utilised to determine the effects of feral cattle and fire on the distribution and abundance of large macropods in the North Kimberley bioregion. Feral cattle density and biomass exceeded that of macropods regardless of survey technique. Density estimates for cattle were up to 125 times higher (0.3–10.0 km-2) than estimates for macropods (0.08–0.49 km-2). Cattle biomass, based on the aerial survey estimates (corrected for perception bias), were 15 and 95 times higher than macropods for infertile (279 vs. 19 kg km-2) and fertile savannas (518 vs. 5 kg km-2), respectively. Proximity to the nearest pastoral station was a significant predictor of the aerial sightings of feral cattle (P ≤ 0.05). Abundance and foraging activity of cattle were positively associated (P ≤ 0.05) with recently burnt areas. In contrast, camera trapping showed agile wallaby and wallaroo occurrence and foraging were associated with longer unburnt areas (P ≤ 0.05). Agile wallaby and wallaroo were negatively associated with cattle (P ≤ 0.05) and showed substantial diurnal and seasonal separation consistent with an antagonistic interspecific interaction. Results also suggest that the agile wallaby is the primary prey of the dingo, not wallaroo. Collectively, this study suggests that recent landscape changes such as altered fire regimes and introduced herbivores have negatively impacted large grazing macropod species.

Connectivity, which is a fundamental aspect of any landscape, has been shown to have a nonlinear relationship with the amount of natural habitat, with a marked decrease at intermediate levels of coverage. Impacts on connectivity vary according to how natural habitat is removed. We analyzed connectivity in the Brazilian Cerrado (tropical savanna), a 2 million-km2 biodiversity hotspot. We evaluated the effects of habitat removal on connectivity, hypothesizing that a deforestation threshold exists below which connectivity is drastically reduced and that neighboring landscapes have similar patterns of connectivity. We divided the Cerrado into 624 50 × 50 km cells and used the integral index of connectivity (IIC), available in Conefor software, to evaluate changes in connectivity between 2000 and 2017. We analyzed how the intra, flux, and connector components of connectivity vary with changes in percentage of remaining natural habitat. Between 2000 and 2017, 23.9% of the natural habitat of the Cerrado was lost (~ 254,000 km2) and connectivity decreased significantly (W = 179,700, p

The development of new acoustic technologies has promoted remarkable advances in biodiversity monitoring. Passive acoustics is increasingly being used in ecological research to remotely assess animal communities. This recent revolution opens new questions about the precision and efficiency of these emerging methods in tracking biodiversity. However, most of the studies evaluating passive monitoring have been applied on temperate regions and in the short term, limiting the understanding of the potential of these techniques and the development of a general framework for survey design. Based on a year-round monitoring of anuran communities at Brazilian savanna wetlands, we examined efficiency of traditional (active searches, AS) and emerging monitoring methods (passive acoustics, PAM) in detecting species at an increasing scale (hours, days, weeks, and months). We determined species richness on 42 active searches and more than 34,000 audio recordings and defined six comparative scenarios (with unequal and equal sampling efforts) in order to explore the combined effect of sampling effort and sampling duration on the species richness detected by these two methods. Using PAM, we estimated higher regional and local richness (14 species per site on average) than AS (8.3 species per site) and detected all anuran species found by AS. Except when sampling effort was highly biased towards AS (single-hour PAM), passive acoustics was able to find more species than AS in all cases. In scenarios with similar sampling effort, differences in observed species richness depended on the temporal distribution of samples. As PAM covered a wider daily and seasonal period, the number of detected species increased, particularly at the most intensive and prolonged sampling (thirty-full-day PAM). Contrary to expectations, we did not record additional species when using AS. Our results provide evidence that passive acoustics is an efficient monitoring technique, offering a higher capacity to detect vocal species in biodiversity surveys than traditional methods, especially when applied in the long term. Sampling scenarios revealed that species detection on monitoring programs is associated with both sampling effort and sampling duration. Thus, due to the potential of PAM to increase these two parameters, this technique can reach better outcomes and be particularly advised for ecological research. These findings can assist researchers in survey design under tropical environments and in determining suitable sampling efforts when applying acoustic monitoring programs.

Native mammals are suffering widespread and ongoing population declines across northern Australia. These declines are likely driven by multiple, interacting factors including altered fire regimes, predation by feral cats, and grazing by feral herbivores. In addition, the loss of tree hollows due to frequent, intense fires may also be contributing to the decline of hollow-dependent mammals. We currently have little understanding of how the availability of tree hollows influences populations of hollow-dependent mammals in northern Australian savannas. Here, we test the hypothesis that the abundance of hollow-dependent mammals is higher in areas with a greater availability of tree hollows. We used camera-trap data from 82 sites across the savannas of Melville Island, the largest island in monsoonal northern Australia. Royle–Nichols abundance-induced heterogeneity models were used to investigate the biophysical correlates of the abundance of three threatened mammals: northern brushtail possum (Trichosurus vulpecula arnhemensis), black-footed tree-rat (Mesembriomys gouldii), and brush-tailed rabbit-rat (Conilurus penicillatus). Our analyses included two variables that reflect the availability of tree hollows: the density of tree hollows, estimated from the ground, and the density of large eucalypt trees (Eucalyptus and Corymbia spp.). We found no evidence that the abundance of the three hollow-dependent mammals is positively associated with the availability of tree hollows on Melville Island. Despite their reliance on hollow-bearing trees for denning, the abundance of these mammals appears to be more strongly associated with other factors, such as the characteristics of the understory (i.e., shrub density), which affords protection from predators (including feral cats) and access to food resources. Future conservation management should aim to maintain a dense, diverse understory by managing fire and feral herbivores to facilitate the persistence of hollow-dependent mammals across northern Australia.

Amazonian savannas are isolated patches of open habitats within an array of extensive tropical forest. The mammal fauna of the savannas in the Alter do Chão region (Santarém Municipality), is dominated by Necromys lasiurus, whose populations have been studied by researchers of the National Institute of Amazonian Research since 1983. Here, we summarize the studies and advances made so far to better understand aspects related to population dynamics and ecology of savanna rodents and the strategies they use to persist in an environment with frequent fires subject to global climatic influences. In the Amazonian savannas the species acts as a seed disperser and population fluctuations are related to invertebrate availability, but not with fire or vegetation structure. Global climate appears to affect N. lasiurus population dynamics at local scale (i.e., plot scale) but not at the regional scale of the Alter do Chão savannas. The long-term studies in Alter do Chão generated many advances about Necromys lasiurus population dynamics and ecology, including aspects relating to feeding, home range, animal-plant interactions, the effects of fire and climate change.

In this work we present a procedure for building a dataset of fire reference perimeters over the African continent from Sentinel-2 (S2) time series. The strategy relies on a sampling scheme designed on the characteristics of the S2 tiling system to provide units suitable for statistical sampling of validation units. The S2 archive is searched to extract cloud free images for building time series that are classified with a Random Forest algorithm to provide fire reference perimeters. A test S2 tile over Tropical savanna (35 LMD) is used to assess the accuracy of S2 reference perimeters by comparison with polygons of burned areas extracted from high resolution Planetscope data.

The Brazilian Cerrado consists of a highly heterogeneous tropical savanna, and its biomass stocks are highly variable. Mapping and monitoring these stocks is not trivial. To address this challenge, we built an aboveground woody biomass (AGWB) model for the Cerrado biome using 30-m resolution optical satellite imagery (Landsat-5 and Landsat-8), 25-m resolution SAR imagery (ALOS and ALOS-2), and a set of plot-based and LiDAR-derived AGWB estimates. We implemented both a Classification and Regression Tree (CART) and a Random Forest (RF) algorithm to model AGWB over the native vegetation for the year 2019 in the Cerrado. The RF algorithm resulted in a slightly better result $(\mathrm{R}^{2}=53\%;\text{ rel. RMSE} =57\%)$ than, the CART model $(\mathbf{R}^{2}=45\%\ \text{ rel. RMSE} =63\% 1$ , but our map shows an underestimation of very high AGWB (negative bias over 200 t.ha-1) and a slight overestimation of low AGWB (positive bias).

The Brazilian savanna (Cerrado) has been heavily impacted by agricultural activities over the last four to five decades, and reliable estimates of reference evapotranspiration (ETo) are needed for water resource management and irrigation agriculture. The Penman–Monteith (PM) is one of the most accepted models for ETo estimation, but it requires many inputs that are not commonly available. Therefore, assessing the FAO guidelines to compute ETo when meteorological data are missing could lead to a better understanding of which variables are critically important for reliable estimates of ETo and how climatic variables are related to water requirements and atmospheric demands. In this study, ETo was computed for a grass-dominated part of the Cerrado from April 2010 to August 2019. We tested 12 different scenarios considering radiation, relative humidity, and/or wind speed as missing climatic data using guidelines given by the FAO. Our results presented that wind speed and actual vapor pressure do not affect ETo estimates as much as the other climatic variables, therefore, in the Cerrado’s conditions, wind speed and relative humidity measurements are less required than temperature and radiation data. When radiation data were missing, the computed ETo was overestimated compared to the benchmark. FAO procedures to estimate the net radiation presented good results during the wet season, however, during the dry season, their results were overestimated because the method could not estimate negative Rn. Our results indicate that radiation data have the highest impact on ETo for our study area and presumably for regions with similar climatic conditions. In addition, those FAO procedures for estimating radiation are not suitable when radiation data are missing.

Despite their size and contribution to the global carbon cycle, we have limited understanding of tropical savannas and their current trajectory with climate change and anthropogenic pressures. Here we examined interannual variability and externally forced long-term changes in carbon and water exchange from a high rainfall savanna site in the seasonal tropics of north Australia. We used an 18-year flux data time series (2001-2019) to detect trends and drivers of fluxes of carbon and water. Significant positive trends in gross primary productivity (GPP, 15.4 g C m2 y-2 ), ecosystem respiration (Reco , 8.0 g C m2 y-2 ), net ecosystem productivity (NEE, 7.4 g C m2 y-2 ) and ecosystem water use efficiency (WUE, 0.0077 g C mm-1 y-1 ) were computed. There was a weaker, non-significant trend in latent energy exchange (LE, 0.34 W m-2 y-1 ). Rainfall from a nearby site increased statistically over a 45-year period during the observation period. To examine dominant drivers of changes in GPP and WUE, we used a random forest approach and a terrestrial biosphere model to conduct an attribution experiment. Radiant energy was the dominant driver of wet season fluxes, whereas soil water content dominated dry season fluxes. The model attribution suggested that [CO2 ], growing season length and dry season Tair accounting for 90% of the modelled trend in GPP and WUE. Positive trends in fluxes were largest in the dry season implying tree components were a larger contributor than the grassy understory. Fluxes and environmental drivers were not significant during the wet season, the period when grasses are active. The site is potentially still recovering from a cyclone 45 years ago and regrowth from this event may also be contributing to the observed trends in sequestration, highlighting the need to understand fluxes and their drivers from sub-diurnal to decadal scales.

The Brazilian Cerrado is a highland tropical savanna considered a biodiversity hotspot with many endemic species of plants and animals. Over the years, most of the native areas of this biome became arable areas, and with inadequate management, some are nowadays at varying levels of degradation stage. Crop-livestock integrated systems (CLIS) are one option for the recovery of areas in degradation, improving the physicochemical and biological characteristics of the soil while increasing income and mitigating risks due to product diversification. Little is known about the effect of CLIS on the soil microbial community. Therefore, we perform this pilot case study to support further research on recovering degraded areas. The bacterial and fungal soil communities in the area with CLIS were compared to an area under moderate recovery (low-input recovering - LI) and native savanna (NS) area. Bacterial and fungal communities were investigated by 16S and ITS rRNA gene sequencing (deep rRNA sequencing). Ktedonobacteraceae and AD3 families were found predominantly in LI, confirming the relationship of the members of the Chloroflexi phylum in challenging environmental conditions, which can be evidenced in LI. The CLIS soil presented 63 exclusive bacterial families that were not found in LI or NS and presented a higher bacterial richness, which can be related to good land management. The NS area shared 21 and 6 families with CLIS and LI, respectively, suggesting that the intervention method used in the analyzed period brings microbial diversity closer to the conditions of the native area, demonstrating a trend of approximation between NS and CLIS even in the short term. The most abundant fungal phylum in NS treatment was Basidiomycota and Mucoromycota, whereas Ascomycota predominated in CLIS and LI. The fungal community needs more time to recover and to approximate from the native area than the bacterial community. However, according to the analysis of bacteria, the CLIS area behaved differently from the LI area, showing that this treatment induces a faster response to the increase in species richness, tending to more accelerated recovery. Results obtained herein encourage CLIS as a sustainable alternative for recovery and production in degraded areas.

Made available in DSpace on 2021-06-25T11:03:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-06-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The Cerrado is the most diverse tropical savanna in the world. As a fire-prone ecosystem, natural fire in the Cerrado shapes plant communities and drives evolutionary processes. Human activities and landscape management can alter natural fire regimes and reshape Cerrado dynamics, making biodiversity conservation a challenge, particularly in densely populated areas. We reconstructed the historical fire regime of three protected areas (PA) and their buffer zones in São Paulo state to understand how current fire exclusion policies are affecting fire regimes and to measure how human-climate-fire relationships can change in areas under different land management. We used Landsat satellite imagery, from 1984 to 2017, with 30 m of spatial resolution and 16 days of temporal resolution. In total, we mapped 49,471 ha of burned area, and we detected variations in fire frequency and fire size among sites. PA dominated by open savanna in Itirapina concentrated 93 % of all observed fires, while PA dominated by forest-like formations in Assis represented only 2% of the fires. Annual rainfall showed a very weak relationship (R2 = 0.04) with annual total burned area, while the rainfall split between dry and wet seasons showed a tendency to have a fuel moisture effect which determined the vegetation available to burn in the dry season (R² = 0.09). Fire regimes in PA were similar to those observed in buffer zones suggesting that fire-exclusion policies do not effectively prevent fires in PA that are surrounded by an anthropic matrix where fire is often used. When we included human factors in addition to rainfall, our models explained 44 % of variation of burned areas. We conclude that fire regimes in São Paulo Cerrado have been modified by humans and that fire exclusion is not a suitable policy for protected areas in this fire-prone ecosystem. Universidade Estadual Paulista (UNESP) Instituto de Biociências Departamento de Ecologia, Avenida 24-A 1515 Centro Universitário Faculdades Integradas de Ourinhos Departamento de Agronomia, Ourinhos Biological and Environmental Sciences Faculty of Natural Sciences Stirling University Instituto Florestal Floresta Estadual de Assis, Cx Postal 104 Universidade Estadual do Maranhão (UEMA) Programa de Pós-graduação em Agricultura e Ambiente Universidade Estadual do Maranhão (UEMA) Programa de Pós-graduação em Geografia Natureza e Dinâmica do Espaço Universidade Estadual Paulista (UNESP) Instituto de Biociências Departamento de Ecologia, Avenida 24-A 1515 FAPESP: #2014/12728-1 CNPq: #303179/2016-3

The etiology and distribution of foliar fungal diseases of citrus in Panama were studied in this work. In total, 85 orchards spanning six provinces were surveyed from 2011 to 2013. Symptoms observed ranged from yellow-brown spots on the abaxial surface of the leaves, brown lesions on petals, twig dieback as well as raised pustules on leaves and fruit. Representative fungal isolates obtained from symptomatic plant tissues were identified based on morphological characteristics, sequences of the ITS, EF1-α and TUB2 loci, and pathogenicity tests. Citrus greasy spot, caused by Zasmidium citri-griseum (=Mycosphaerella citri), was identified as the most prevalent fungal disease of citrus in Panama, confirmed in 68.2% of the orchards. Postbloom fruit drop (PFD) and Key lime anthracnose, caused by Colletotrichum acutatum sensulato, and melanose, caused by Diaporthe citri, were identified for the first time in Panama. Citrus scab, caused by Elsinoe fawcettii, was also detected. Greasy spot was found mainly in areas with a tropical monsoon climate (Am) and to a lesser extent in tropical savanna (Aw) and tropical rainforest (Af) climates. Melanose, PFD and citrus scab were detected only in areas with Am and Af climates. Information about the etiology and geographic distribution of fungal diseases in Panama will help to design effective strategies for disease management.

Preliminary values of whole organism concentration ratio (CRwo-soil) were derived for terrestrial vertebrates of an Australian tropical savanna environment. Wildlife groups included bird, bat, ground-dwelling mammal and reptile. Sample data for some of the wildlife groups (bird and bat in particular) were limited. The bird and bat CRwo-soil values were generally lower than the ground-dwelling mammal and reptile CRwo-soil values based on the available data. Arithmetic mean CRwo-soil values for two species of native marsupial and two species of non-native placental were not significantly different (p

A new threat now confronts the Amazon in the form of a massive infrastructure program, the Initiative for the Integration of the Regional Infrastructure of South America, or IIRSA. This article presents results of a projection analysis showing that IIRSA could push the Amazonian forest past a "tipping point," replacing it with tropical savanna. Such an event would degrade biodiversity, reduce carbon storage, and harm continental agriculture, dependent on moisture transport from forest-based rainfall recycling. The article considers environmental policy in Brazil and discusses its weakening over time. One short-term approach to conservation is provided by indigenous resistance to development forces. The article presents a case study of the Munduruku people, who recently stopped construction of a large dam on the Tapajos River in defending their territories. It argues that more research is needed to understand the impacts of IIRSA, which is proceeding in the dark.