Concordance between Phylogeographical and Biogeographical Patterns in the Brazilian Cerrado: Diversification of the Endemic Tree Dalbergia miscolobium (Fabaceae)

Few studies have addressed the phylogeography of species of the Cerrado, the largest savanna biome of South America. Here we aimed to investigate the phylogeographical structure of Dalbergia miscolobium, a widespread tree from the Cerrado, and to verify its concordance with plant phylogeographical and biogeographical patterns so far described. A total of 287 individuals from 32 populations were analyzed by sequencing the trnL intron of the chloroplast DNA and the internal transcribed spacer of the nuclear ribosomal DNA. Analysis of population structure and tests of population expansion were performed and the time of divergence of haplotypes was estimated. Twelve and 27 haplotypes were identified in the cpDNA and nrDNA data, respectively. The star-like network configuration and the mismatch distributions indicated a recent spatial and demographic expansion of the species. Consistent with previous tree phylogeographical studies of Cerrado trees, the cpDNA also suggested a recent expansion towards the southern Cerrado. The diversity of D. miscolobium was widespread but high levels of genetic diversity were found in the Central Eastern and in the southern portion of Central Western Cerrado. The combined analysis of cpDNA and nrDNA supported a phylogeographic structure into seven groups. The phylogeographical pattern showed many concordances with biogeographical and phylogeographical studies in the Cerrado, mainly with the Cerrado phytogeographic provinces superimposed to our sampling area. The data reinforced the uniqueness of Northeastern and Southeastern Cerrados and the differentiation between Eastern and Western Central Cerrados. The recent diversification of the species (estimated between the Pliocene and the Pleistocene) and the ‘genealogical concordances’ suggest that a shared and persistent pattern of species diversification might have been present in the Cerrado over time. This is the first time that an extensive ‘genealogical concordance’ between phylogeographic and phytogeographic patterns is shown for the Cerrado biome.     

Biogeography and priority areas for the conservation of bats in the Brazilian Cerrado

In this study, we describe the distribution pattern of bat species and select priority areas for the conservation of the Cerrado based on a systematic planning approach. We estimated species richness and calculated the total beta diversity based on Sørensen’s dissimilarity index (βsor). We estimated the species turnover using Simpson’s dissimilarity index (βsim). We then evaluated the nesting (βsne) by the difference between the dissimilarity indices (βsor and βsim). Based on this analysis, we identified the priority areas for the conservation of bats in the Cerrado based on the zonation approach. We found that the species richness and beta diversity of bats in the Cerrado are concentrated primarily in the central and northern portions of the biome. We also discovered that the conservation units of the Cerrado are ineffective for the protection of species with a restricted distribution (≤ 150 grid cells), such as Vampyrum spectrum, for which we propose the creation of new conservation units that better cover the diversity patterns observed in the present study. By conserving this diversity, we will also be protecting local habitats, which will in turn enable the survival of a wide range of species, and provide the ecosystems with the capacity to respond adequately to future changes in the environment.     

Endemic bird species and conservation in the Cerrado Region, South America

A general overview of the largest South American savanna region, the Cerrado Region, is presented. Using simple approaches, I analyse the distribution of the bird species endemic to this region in order to test the hypothesis that areas harbouring local aggregates of restricted-range endemics have remained stable during the successive Quaternary climatic-vegetational changes. This hypothesis seems not to be generally valid for birds of the Cerrado Region, as restricted-range endemic species exist both in areas that remained stable (Central Goia´s Plateau) and areas that remain unstable (Araguaya and Parana~ River valleys, Espinhac¸o Plateau) during the Late Pleistocene. I also discuss some aspects of the conservation in the Cerrado Region, and suggest that the dry forests of the River Parana~ Valley, Goia´s, must be considered the area with the highest priority for the creation of new reserves in the Cerrado Region.     

Vascular Patterns in Iguanas and Other Squamates: Blood Vessels and Sites of Thermal Exchange

Squamates use the circulatory system to regulate body and head temperatures during both heating and cooling. The flexibility of this system, which possibly exceeds that of endotherms, offers a number of physiological mechanisms to gain or retain heat (e.g., increase peripheral blood flow and heart rate, cooling the head to prolong basking time for the body) as well as to shed heat (modulate peripheral blood flow, expose sites of thermal exchange). Squamates also have the ability to establish and maintain the same head-to-body temperature differential that birds, crocodilians, and mammals demonstrate, but without a discrete rete or other vascular physiological device. Squamates offer important anatomical and phylogenetic evidence for the inference of the blood vessels of dinosaurs and other extinct archosaurs in that they shed light on the basal diapsid condition. Given this basal positioning, squamates likewise inform and constrain the range of physiological thermoregulatory mechanisms that may have been found in Dinosauria. Unfortunately, the literature on squamate vascular anatomy is limited. Cephalic vascular anatomy of green iguanas (Iguana iguana) was investigated using a differential-contrast, dual-vascular injection (DCDVI) technique and high-resolution X-ray microcomputed tomography (μCT). Blood vessels were digitally segmented to create a surface representation of vascular pathways. Known sites of thermal exchange, consisting of the oral, nasal, and orbital regions, were given special attention due to their role in brain and cephalic thermoregulation. Blood vessels to and from sites of thermal exchange were investigated to detect conserved vascular patterns and to assess their ability to deliver cooled blood to the dural venous sinuses. Arteries within sites of thermal exchange were found to deliver blood directly and through collateral pathways. The venous drainage was found to have multiple pathways that could influence neurosensory tissue temperature, as well as pathways that would bypass neurosensory tissues. The orbital region houses a large venous sinus that receives cooled blood from the nasal region. Blood vessels from the nasal region and orbital sinus show anastomotic connections to the dural sinus system, allowing for the direct modulation of brain temperatures. The generality of the vascular patterns discovered in iguanas were assessed by firsthand comparison with other squamates taxa (e.g., via dissection and osteological study) as well as the literature. Similar to extant archosaurs, iguanas and other squamates have highly vascularized sites of thermal exchange that likely support physiological thermoregulation that “fine tunes” temperatures attained through behavioral thermoregulation.     

No Evidence of Habitat Loss Affecting the Orchid Bees Eulaema nigrita Lepeletier and Eufriesea auriceps Friese (Apidae: Euglossini) in the Brazilian Cerrado Savanna

Habitat loss, landscape fragmentation, and agriculture intensification constitute the main threats to bees. As the organisms responsible for almost one third of the food produced worldwide, there are growing concerns on bees’ response to human-related disturbances. Among all bee groups, orchid bees (Apidae: Euglossini) compose an interesting group to test landscape-related hypotheses. In here, we tested the effect of landscape features (amount of anthropic areas and isolation) on the probability of occurrence and the abundances of both Eulaema nigrita Lepeletier and Eufriesea auriceps Friese in the Cerrado savanna. In general, we did not observe any effect of landscape features on the probability of occurrence and abundances of both species in our sampling sites. Given their potential high dispersal abilities, these bee species may be less sensitive to fragmented landscapes or even positively affected by the increase of anthropic habitats. Since we sampled many E. nigrita specimens in highly preserved Cerrado savanna areas, we believe that at least for this biome, this species may not be a good indicator of landscape disturbance.     

Phylogeographical structure of the neotropical forest tree Hymenaea courbaril (Leguminosae: Caesalpinioideae) and its relationship with the Vicariant Hymenaea stigonocarpa from Cerrado

The phylogeography of Hymenaea courbaril var. stilbocarpa from Atlantic Forest and riverine forests of the Cerrado biome in central and southeastern Brazil was investigated. The data were compared with those of its congeneric Hymenaea stigonocarpa, a typical tree from savanna. In the Cerrado, H. courbaril var. stilbocarpa is found in sites contiguous with those of H. stigonocarpa, and they share common life-history attributes. The psbC/trnS3 region of the chloroplast DNA was sequenced in 149 individuals of H. courbaril var. stilbocarpa. High genetic variation was found in this species, with the identification of 18 haplotypes, similarly to what was found in H. stigonocarpa with 23 haplotypes in the same geographic region. Populations of H. courbaril var. stilbocarpa could be structured in 3 phylogeographic groups. Spatial analysis of molecular variation indicated that 46.4% of the genetic variation was due to differences among these groups. Three haplotypes were shared by H. courbaril var. stilbocarpa and H. stigonocarpa, and only 10.5% of the total genetic variation could be attributed to between-species difference. We surmise that during the glacial times, H. courbaril var. stilbocarpa populations must have gone extinct in most parts of the southern of its present-day occurrence area. After climate amelioration, these areas were probably recolonized from northern and eastern. The relatively similar phylogeographic structure of vicariant Hymenaea species suggests that they were subjected to the same impacts during the Quaternary climatic fluctuations. The sharing of haplotypes and the genetic similarity between the 2 Hymenaea species suggest the existence of ancestral polymorphism and/or hybridization.     

Biogeography of Cephalopods in the Southern Ocean Using Habitat Suitability Prediction Models

Our understanding of how environmental change in the Southern Ocean will affect marine diversity, habitats and distribution remain limited. The habitats and distributions of Southern Ocean cephalopods are generally poorly understood, and yet such knowledge is necessary for research and conservation management purposes, as well as for assessing the potential impacts of environmental change. We used net-catch data to develop habitat suitability models for 15 of the most common cephalopods in the Southern Ocean. Using modeled habitat suitability, we assessed favorable areas for each species and examined the relationships between species distribution and environmental parameters. The results compared favorably with the known ecology of these species and with spatial patterns from diet studies of squid predators. The individual habitat suitability models were overlaid to generate a “hotspot” index of species richness, which showed higher numbers of squid species associated with various fronts of the Antarctic circumpolar current. Finally, we reviewed the overall distribution of these species and their importance in the diet of Southern Ocean predators. There is a need for further studies to explore the potential impacts of future climate change on Southern Ocean squid.     

Biogeography of the Primates of Guyana: Effects of Habitat Use and Diet on Geographic Distribution

Species that exploit a wide range of resources or habitats (generalists) tend to be widely distributed, whereas species that exploit a narrow range of resources or habitats (specialists) often have a limited distribution. The distribution patterns are thought to result from specialists using relatively smaller habitats than those exploited by generalists. I used data from 1,725 km of primate surveys that I conducted in Guyana to test these hypotheses. Habitat breadth is the total number of different habitat types occupied by each species. I used the total number of different food categories exploited by each species to measure dietary breadth. Geographic range size is correlated with habitat breadth but not with dietary breadth or body size for the 8 primate species in Guyana. Habitat generalists—red howlers and wedge-capped capuchins—range into all habitats. Habitat specialists—spider monkeys, brown bearded sakis, and golden-handed tamarins—range only into large habitats. Habitat generalists tend to be dietary type specialists in Guyana. I suggest that only habitat generalists can subsist on the low-quality foods in small habitats in Guyana. Conversely, habitat specialists tend to be dietary type generalists in Guyana. They must feed on a variety of food types in large habitats. However, using the number of food categories exploited as a measure of dietary breadth may be only a weak aspect of multidimensional niche. Researchers testing biogeographic hypotheses associated with dietary breadth should consider including multivariate indicators of both the types of food categories eaten and the number of plant species exploited.     

Montane Refugia for Endemic and Red Listed Dragonflies in the Cape Floristic Region Biodiversity Hotspot

One of the features of many endemic organisms is that they are highly spatially restricted, and habitat specialists. The Kogelberg Biosphere Reserve (KBR) is a major centre of plant endemism within a global hotspot, the Cape Floristic Region (CFR). Dragonflies in this botanical hotspot have a range of habitat specialization from narrow-range specialists to widespread generalists, with an unusually strong bias towards the specialists. A huge 53% of dragonfly individuals and 26% of taxa recorded are national endemics, and three species are Red Listed. Thus, a group of predatory insects, which are largely not dependent on plant composition, mirrors the level of habitat specialization and restricted distributions of the plants at the spatial scale of the whole reserve. Although some studies caution the use of one taxon as a surrogate for another, the results here show that at the reserve scale in this global hotspot there can be remarkable concordance, suggesting further studies on other taxa should be carried out to determine the full extent of taxonomic concordance in this irreplaceable area.     

Patterns in the organization of Cerrado pond biodiversity in Brazilian pasture landscapes

There is a worldwide concern on the loss of pond biodiversity in human dominated landscapes. Nevertheless, agricultural activities appear to increase pond number in the Brazilian Cerrado through damming streams for cattle raising. These man-made ponds may represent important landscape features, but their importance to regional biodiversity has not yet been studied. Here, we evaluated differences in alpha and beta diversity under a multi-taxonomic approach, as well as tested pond size as the main driver of local species richness. We also assessed the importance of environmental heterogeneity through the analysis of the regional species accumulation curves (SAC). The overall result suggests that species turnover was the major component of regional biodiversity for all groups. Major physical and chemical water conditions had no effects on algae, macrophytes, water bugs, and birds species richness. Pond size had a significant effect on Odonata and fish species richness, while water beetles and amphibians were influenced by trophic conditions. Results from regional SAC show variations among different taxonomic groups regarding landscape heterogeneity: only algae, fish, and birds do not reached to an asymptote and had higher z-values. Our results highlight the importance of ponds for biodiversity conservation in increasingly agricultural landscapes in central Brazil.     

Habitat Loss,Not Fragmentation,Drives Occurrence Patterns of Canada Lynx at the Southern Range Periphery

Peripheral populations often experience more extreme environmental conditions than those in the centre of a species'' range. Such extreme conditions include habitat loss, defined as a reduction in the amount of suitable habitat, as well as habitat fragmentation, which involves the breaking apart of habitat independent of habitat loss. The ‘threshold hypothesis’ predicts that organisms will be more affected by habitat fragmentation when the amount of habitat on the landscape is scarce (i.e., less than 30%) than when habitat is abundant, implying that habitat fragmentation may compound habitat loss through changes in patch size and configuration. Alternatively, the ‘flexibility hypothesis’ predicts that individuals may respond to increased habitat disturbance by altering their selection patterns and thereby reducing sensitivity to habitat loss and fragmentation. While the range of Canada lynx (Lynx canadensis) has contracted during recent decades, the relative importance of habitat loss and habitat fragmentation on this phenomenon is poorly understood. We used a habitat suitability model for lynx to identify suitable land cover in Ontario, and contrasted occupancy patterns across landscapes differing in cover, to test the ‘threshold hypothesis’ and ‘flexibility hypothesis’. When suitable land cover was widely available, lynx avoided areas with less than 30% habitat and were unaffected by habitat fragmentation. However, on landscapes with minimal suitable land cover, lynx occurrence was not related to either habitat loss or habitat fragmentation, indicating support for the ‘flexibility hypothesis’. We conclude that lynx are broadly affected by habitat loss, and not specifically by habitat fragmentation, although occurrence patterns are flexible and dependent on landscape condition. We suggest that lynx may alter their habitat selection patterns depending on local conditions, thereby reducing their sensitivity to anthropogenically-driven habitat alteration.     

Biogeography of Dwarf Lemurs: Genetic Evidence for Unexpected Patterns in Southeastern Madagascar

Seven species of dwarf lemurs (Cheirogaleus spp.) are currently recognized after a recent revision of the genus. During a field study in southeastern Madagascar, we observed 3 distinct morphotypes of Cheirogaleus resembling Cheirogaleus medius, C. major and C. crossleyi. In particular, for Cheirogaleus crossleyi southeastern Madagascar was far away from the known distribution range of the species when referring to the recent revision of the genus. In order to clarify the taxonomic status of the 3 morphotypes, we compared field samples from southeastern Madagascar to museum specimens from several locations in Madagascar and to field samples from Kirindy/CFPF, western Madagascar by genetic analyses using the mitochondrial cytochrome b gene. Genetic data yield strong support for 2 of the 3 morphotypes to represent Cheirogaleus medius and C. major. The third morphotype is genetically closely related to Cheirogaleus crossleyi, albeit more distantly than the other 2 morphotypes to the respective reference samples. The genetic distance is related to a considerable geographic distance between the location of our field study and the origin of the respective reference specimen, because Cheirogaleus crossleyi had been reported only from northern Madagascar. Our field observations indicate an isolated population in southeastern Madagascar. We propose to identify them as Cheirogaleus crossleyi and discuss the population genetic and biogeographic considerations supporting this conclusion.     

喀斯特生境中猕猴的活动节律和时间分配

2006年9月至2007年8月,在广西弄岗国家级自然保护区选择一群猕猴(Macaca mulatta)作为观察对象,采用瞬时扫描取样法收集相关的行为数据,以日活动节律和活动时间分配为切人点,探讨猕猴对喀斯特石山生境的行为适应策略.结果表明,猕猴的日活动节律表现为上午和下午的觅食高峰,中午进入长时间的休息期.这可能与白天...     

Patterns of Leaf Biochemical and Structural Properties of Cerrado Life Forms: Implications for Remote Sensing

AimThe general goal of this study is to investigate and analyze patterns of ecophysiological leaf traits and spectral response among life forms (trees, shrubs and lianas) in the Cerrado ecosystem. In this study, we first tested whether life forms are discriminated through leaf level functional traits. We then explored the correlation between leaf-level plant functional traits and spectral reflectance.LocationSerra do Cipo National Park, Minas Gerais, Brazil.MethodsSix ecophysiological leaf traits were selected to best characterize differences between life forms in the woody plant community of the Cerrado. Results were compared to spectral vegetation indices to determine if plant groups provide means to separate leaf spectral responses.ResultsValues obtained from leaf traits were similar to results reported from other tropical dry sites. Trees and shrubs significantly differed from lianas in terms of the percentage of leaf water content and Specific Leaf Area. Spectral indices were insufficient to capture the differences of these key traits between groups, though indices were still adequately correlated to overall trait variation.ConclusionThe importance of life forms as biochemical and structurally distinctive groups is a significant finding for future remote sensing studies of vegetation, especially in arid and semi-arid environments. The traits we found as indicative of these groups (SLA and water content) are good candidates for spectral characterization. Future studies need to use the full wavelength (400 nm–2500 nm) in order to capture the potential response of these traits. The ecological linkage to water balance and life strategies encourages these traits as starting points for modeling plant communities using hyperspectral remote sensing.     

Biogeographic Distribution Patterns and Their Correlates in the Diverse Frog Fauna of the Atlantic Forest Hotspot

Anurans are a highly diverse group in the Atlantic Forest hotspot (AF), yet distribution patterns and species richness gradients are not randomly distributed throughout the biome. Thus, we explore how anuran species are distributed in this complex and biodiverse hotspot, and hypothesize that this group can be distinguished by different cohesive regions. We used range maps of 497 species to obtain a presence/absence data grid, resolved to 50×50 km grain size, which was submitted to k-means clustering with v-fold cross-validation to determine the biogeographic regions. We also explored the extent to which current environmental variables, topography, and floristic structure of the AF are expected to identify the cluster patterns recognized by the k-means clustering. The biogeographic patterns found for amphibians are broadly congruent with ecoregions identified in the AF, but their edges, and sometimes the whole extent of some clusters, present much less resolved pattern compared to previous classification. We also identified that climate, topography, and vegetation structure of the AF explained a high percentage of variance of the cluster patterns identified, but the magnitude of the regression coefficients shifted regarding their importance in explaining the variance for each cluster. Specifically, we propose that the anuran fauna of the AF can be split into four biogeographic regions: a) less diverse and widely-ranged species that predominantly occur in the inland semideciduous forests; b) northern small-ranged species that presumably evolved within the Pleistocene forest refugia; c) highly diverse and small-ranged species from the southeastern Brazilian mountain chain and its adjacent semideciduous forest; and d) southern species from the Araucaria forest. Finally, the high congruence among the cluster patterns and previous eco-regions identified for the AF suggests that preserving the underlying habitat structure helps to preserve the historical and ecological signals that underlie the geographic distribution of AF anurans.     

Patterns of Endemism and Habitat Selection in Coalbed Microbial Communities

Microbially produced methane, a versatile, cleaner-burning alternative energy resource to fossil fuels, is sourced from a variety of natural and engineered ecosystems, including marine sediments, anaerobic digesters, shales, and coalbeds. There is a prevailing interest in developing environmental biotechnologies to enhance methane production. Here, we use small-subunit rRNA gene sequencing and metagenomics to better describe the interplay between coalbed methane (CBM) well conditions and microbial communities in the Alberta Basin. Our results show that CBM microbial community structures display patterns of endemism and habitat selection across the Alberta Basin, consistent with observations from other geographical locations. While some phylum-level taxonomic patterns were observed, relative abundances of specific taxonomic groups were localized to discrete wells, likely shaped by local environmental conditions, such as coal rank and depth-dependent physicochemical conditions. To better resolve functional potential within the CBM milieu, a metagenome from a deep volatile-bituminous coal sample was generated. This sample was dominated by Rhodobacteraceae genotypes, resolving a near-complete population genome bin related to Celeribacter sp. that encoded metabolic pathways for the degradation of a wide range of aromatic compounds and the production of methanogenic substrates via acidogenic fermentation. Genomic comparisons between the Celeribacter sp. population genome and related organisms isolated from different environments reflected habitat-specific selection pressures that included nitrogen availability and the ability to utilize diverse carbon substrates. Taken together, our observations reveal that both endemism and metabolic specialization should be considered in the development of biostimulation strategies for nonproductive wells or for those with declining productivity.