Ectomycorrhizal fungal diversity and community structure on three co-occurring leguminous canopy tree species in a Neotropical rainforest

? The ectomycorrhizal (ECM) symbiosis was historically considered restricted to the temperate zones, but recent studies have shown the importance of this symbiosis across the tropics. We examined ECM fungal diversity, host plant phylogeny and ECM host preferences in a rainforest dominated by the leguminous host plants Dicymbe corymbosa, Dicymbe altsonii and Aldina insignis. ? Ectomycorrhizal fungi were identified by internal transcribed spacer rDNA sequencing and host species were verified with chloroplast trnL sequencing. To test whether Dicymbe and Aldina represent independent gains of the ECM symbiosis, we constructed a Fabaceae phylogeny using MatK and trnL. We identified four independent ECM lineages within the Fabaceae. ? We detected a diverse community of 118 ECM species dominated by the /clavulina, /russula-lactarius, /boletus, and /tomentella-thelephora lineages. Ectomycorrhizal species in Agaricales, Atheliales and Polyporales may represent previously unrecognized tropical-endemic ECM lineages. Previous studies suggested that ECM fungi did not diversify in the tropics, but the /clavulina lineage appears to have a center of diversity in tropical South America. ? Dicymbe and Aldina represent independent gains of the ECM symbiosis in Fabaceae but their fungal symbionts showed no host preferences. Spatial factors are more important than hosts in structuring the ECM fungal community in this ecosystem.     

Neotropical bats: estimating species diversity with DNA barcodes

DNA barcoding using the cytochrome c oxidase subunit 1 gene (COI) is frequently employed as an efficient method of species identification in animal life and may also be used to estimate species richness, particularly in understudied faunas. Despite numerous past demonstrations of the efficiency of this technique, few studies have attempted to employ DNA barcoding methodologies on a large geographic scale, particularly within tropical regions. In this study we survey current and potential species diversity using DNA barcodes with a collection of more than 9000 individuals from 163 species of Neotropical bats (order Chiroptera). This represents one of the largest surveys to employ this strategy on any animal group and is certainly the largest to date for land vertebrates. Our analysis documents the utility of this tool over great geographic distances and across extraordinarily diverse habitats. Among the 163 included species 98.8% possessed distinct sets of COI haplotypes making them easily recognizable at this locus. We detected only a single case of shared haplotypes. Intraspecific diversity in the region was high among currently recognized species (mean of 1.38%, range 0-11.79%) with respect to birds, though comparable to other bat assemblages. In 44 of 163 cases, well-supported, distinct intraspecific lineages were identified which may suggest the presence of cryptic species though mean and maximum intraspecific divergence were not good predictors of their presence. In all cases, intraspecific lineages require additional investigation using complementary molecular techniques and additional characters such as morphology and acoustic data. Our analysis provides strong support for the continued assembly of DNA barcoding libraries and ongoing taxonomic investigation of bats.     

Species diversity of bats (Mammalia: Chiroptera) in Iwokrama Forest, Guyana, and the Guianan subregion: implications for conservation

Fourteen species of bats are reported for the first time from Guyana (Saccopteryx gymnura, Micronycteris brachyotis, M. homezi, Lichonycteris obscura, Anoura latidens, Vampyressa pusilla, Vampyrodes caraccioli, Eptesicus chiriquinus, Cynomops paranus, Molossops neglectus, Molossus sp., Molossus coibensis, Molossus sinaloae, and Promops centralis) bringing the known bat diversity for the country to 121 species. Information including measurements, reproductive data, distribution, and taxonomy are provided for these species. Seven of these new records were collected in the Iwokrama International Rain Forest Programme site in central Guyana. Eighty-six bat species are now documented from Iwokrama Forest which is the highest species diversity for bats reported from any protected area in the world. There are, however, few tropical sites that have relatively complete inventories. A summary for bat species diversity in southern Venezuela, Guyana, Suriname, and French Guiana indicates that at least 146 species of bats are known from the Guianan subregion. Intense inventory surveys, especially in the often neglected subcanopy, suggest that species richness is probably underestimated in most Neotropical areas. Likewise, species-level diversity in the Guianan subregion is higher than previously suggested. Surveying and monitoring biodiversity are critical to developing a National Protected Areas System in Guyana.     

Tree structure and cavity microclimate: implications for bats and birds

It is widely assumed that tree cavity structure and microclimate affect cavity selection and use in cavity-dwelling bats and birds. Despite the interest in tree structure and microclimate, the relationship between the two has rarely been quantified. Currently available data often comes from artificial structures that may not accurately represent conditions in natural cavities. We collected data on tree cavity structure and microclimate from 45 trees in five cypress-gum swamps in the Coastal Plain of Georgia in the United States in 2008. We used hierarchical linear models to predict cavity microclimate from tree structure and ambient temperature and humidity, and used Aikaike’s information criterion to select the most parsimonious models. We found large differences in microclimate among trees, but tree structure variables explained <28 % of the variation, while ambient conditions explained >80 % of variation common to all trees. We argue that the determinants of microclimate are complex and multidimensional, and therefore cavity microclimate cannot be deduced easily from simple tree structures. Furthermore, we found that daily fluctuations in ambient conditions strongly affect microclimate, indicating that greater weather fluctuations will cause greater differences among tree cavities.     

Prokaryotic diversity and its limits: microbial community structure in nature and implications for microbial ecology

Recent advances in the estimation of prokaryotic diversity have brought us insight into two questions: what is the extent of prokaryotic diversity, and perhaps more importantly, why bother finding out. In this review, we highlight the insights about the extent of diversity that may be gained by considering patterns that occur, or are likely to occur, in the relative abundance of prokaryotic taxa. We posit that global reservoirs of diversity are an important driving force behind patterns in localised diversity seen in leaves, intestines and wastewater treatment reactors. Thus, where the reservoir community is very large and relatively even, chance alone will prevent physically identical communities from having the same, or sometimes even stable, communities. By contrast, communities that tend to be similar (even when not physically identical) and stable are observed where the source diversity is low. Thus the relationship between structure and function in a community can only be understood, predicted and engineered through an understanding of the source of diversity from which the community is drawn.     

Genetic diversity and the genetic structure of natural populations of Chamaecyparis obtusa: implications for management and conservation

We investigated 25 natural populations of Chamaecyparis obtusa using 51 cleaved amplified polymorphic sequence (CAPS) markers, which were developed using information on sequence-tagged sites (STS) in Cryptomeria japonica. Most CAPS markers have codominant expression patterns, and are suitable for population studies because of their robustness and convenience. We estimated various genetic diversity parameters, including average heterozygosity (H(e)) and allelic richness and found that the more peripheral populations tended to have lower genetic diversity than central populations, in agreement with a previous theoretical study. The overall genetic differentiation between populations was low, but statistically significant (G(ST)=0.039), and similar to the level reported in a previous allozyme study. We attempted to detect non-neutral loci associated with local adaptation to clarify the relationship between the fixation index (F(ST)) and H(e) values for each locus and found seven candidates non-neutral loci. Phylogenetic tree analysis of the populations and Bayesian clustering analysis revealed a pattern of gradually increasing isolation of populations with increasing geographical distance. Three populations had a high degree of linkage disequilibrium, which we attribute to severe bottlenecks due to human disturbance or competition with other species during their migration from refugia after the most recent glaciation. We concluded that the small populations in western Japan and in Kanto district are more important, from a conservation perspective, than the populations in central Japan, due to their genetic divergence, relatively small sizes and restricted areas.     

Estimating the genetic diversity and spatial structure of Bulgarian Castanea sativa populations by SSRs: implications for conservation

Sweet chestnut (Castanea sativa Mill.) is a multipurpose species of great ecological and economic importance in southwest Bulgaria. Bulgarian chestnut forests are severely degraded, however, due to the intensive exploitation and bad management that have occurred over the last 2000 years. Given the urgent need to define conservation strategies to preserve the biodiversity of Bulgarian chestnut, we estimated its genetic variability. A set of eight microsatellite primers were used to analyze the genetic diversity and structure of six C. sativa populations distributed throughout the range of species in Bulgaria. Results showed a generally high level of genetic diversity but little divergence among populations. A significant, positive, within-population inbreeding coefficient (Fis) was observed in four populations. A STRUCTURE analysis revealed three genetic clusters. Using a landscape approach, significant genetic barriers among populations were found by integrating genetics with geographical distance. We hypothesize that one population is a relict from a glacial refugium; the structure of the remaining populations is probably the result of a combination of natural events and human impacts. For the purposes of conservation planning, we have identified populations that are particularly rich in diversity and private alleles that are good candidates for preservation.     

Relationships, origin, and diversity of Galapagos tomatoes: implications for the conservation of natural populations

Endemic Galápagos tomatoes (Lycopersicon cheesmanii) are of great value for cultivated tomato (L. esculentum) breeding, and therefore their conservation is of significance. Although within L. cheesmanii there is heterogeneity for many traits and formal infraspecific classification is not justified, here we distinguish three forms, without taxonomic significance, of L. cheesmanii that are of interest to breeders because of their distinctive morphology and habitat preferences: L. cheesmanii 'short' (one- to two-pinnate leaves, short internodes, and coastal habitats), L. cheesmanii 'long' (one- to two-pinnate leaves, long internodes, and inland habitats), and L. cheesmanii forma minor (three- to four-pinnate leaves, short internodes, and coastal habitats). In a recent survey of tomato populations in the Galápagos Islands, we found that several populations of L. cheesmanii reported 30-50 years earlier had disappeared, mostly as a consequence of human activity. In addition, a previously unreported invasive wild red-fruited form, which we named L. esculentum 'Gal cer,' was found on the island of Santa Cruz. The total diversity (estimated with amplified fragment length polymorphisms [AFLPs]) within L. cheesmanii (H(T) = 0.051) is almost as high as that for the mainland wild species L. pimpinellifolium (H(T) = 0.072). Lycopersicon esculentum 'Gal cer,' on the other hand, has a much lower diversity (H(T) = 0.014). Comparison of AFLP fragments shared by L. esculentum 'Gal cer' with other species showed that it is closely related to weedy tomato L. esculentum var. cerasiforme and, therefore, likely of recent origin. Genetic differentiation among the three native L. cheesmanii forms is low (G(ST) = 0.235), indicating that they share a common genetic background. Nonetheless, L. cheesmanii 'short' is about twice as diverse as L. cheesmanii 'long' or L. cheesmanii f. minor. UPGMA cluster and principal components analysis distinguish four groups within Eulycopersicon: L. pimpinellifolium, cultivated L. esculentum, L. esculentum var. cerasiforme including L. esculentum 'Gal cer,' and L. cheesmanii. The geographic distance and genetic distance in the wild forms of Galápagos tomatoes were not correlated. Apart from the pressure of humans, some native L. cheesmanii populations, especially L. cheesmanii 'long,' might be displaced by invasive L. esculentum 'Gal cer' because they share a similar habitat. We did not find evidence of intercrossing of L. cheesmanii with introduced L. esculentum, but occasional hybridization that contributes to loss of genetic integrity of L. cheesmanii cannot be ruled out. Establishment of reserves of L. cheesmanii to protect this species from introduced herbivorous animals and from hybridization with L. esculentum 'Gal cer' would help to conserve L. cheesmanii. Furthermore, accessions collected by C. M. Rick and others in the 1950s-1970s and now stored in germplasm banks could be used to reinstate some extinct populations.     

Predation, resource availability, and community structure in Neotropical water-filled tree holes

Predation and resource availability influence community structure in many aquatic ecosystems. Predators (odonates) and resources (leaf litter) were manipulated to determine their independent effects on macroorganism species richness, abundance, and composition in water-filled tree holes of Barro Colorado Island, Panama. Interactive effects of these factors were also investigated in artificial tree holes. Large odonates reduced species richness in natural tree holes, but did not significantly reduce macroorganism abundance. The presence of larvae of the mosquito Culex urichii and the ceratopogonid midge Bezzia snowi were negatively associated with the presence of large odonate larvae. In natural tree holes, leaf litter addition and removal respectively increased and decreased richness by c. 1 species relative to controls, and macroorganism abundance was greater in litter addition holes than in litter removal holes. Independent effects of predation showed similar patterns in artificial holes, but there was no predator2resource interaction, partly due to the short duration of the experiment. Predators grew faster when litter was abundant, and indirectly reduced litter degradation rates when resources were scarce in artificial holes. Both resource availability and predation influence species richness in water-filled tree holes, but act at different time scales; richness follows productivity (litter quantity) over a period of weeks, whereas effects of predation may span several months.     

Bird diversity in northern Myanmar and conservation implications

We conducted four bird biodiversity surveys in the Putao area of northern Myanmar from 2015 to 2017.Combined with anecdotal information collected between 2012 and 2015,we recorded 319 bird species,including two species (Arborophila mandellii and Lanius sphenocercus) previously unrecorded in Myanmar.Bulbuls (Pycnonotidae),babblers (Timaliidae),pigeons and doves (Columbidae),and pheasants and partridges (Phasianidae) were the most abundant groups of birds recorded.Species richness below 1 500 m a.s.l.was higher than species richness at higher elevations.Our results suggest that the current protected areas in this region should be expanded to lower elevations to cover critical conservation gaps.     

Trophic niche partitioning of cryptic species of long-eared bats in Switzerland: implications for conservation

Dietary niche partitioning is postulated to play a major role for the stable coexistence of species within a community, particularly among cryptic species. Molecular markers have recently revealed the existence of a new cryptic species of long-eared bat, Plecotus macrobullaris, in the European Alps. We studied trophic niches as well as seasonal and regional variations of diet in eight colonies of the three Plecotus species occurring in Switzerland. Faeces were collected monthly from individuals returning to roost after foraging. Twenty-one arthropod categories were recognized from the faeces. All three species fed predominantly on Lepidoptera, which made up 41%, 87% and 88% (means across colonies) of the diet composition of P. auritus, P. macrobullaris and P. austriacus, respectively. The occurrence of numerous fragments of both diurnal and flightless insects in the diet of P. auritus (but rarely in the diet of the other two species) indicates that this species mostly gleans prey from substrates. P. austriacus and P. macrobullaris are more typical aerial feeders. The latter two species have narrow trophic niches, whilst P. auritus has a much broader diet. Comparison of intraspecific and interspecific niche overlaps in P. auritus and P. macrobullaris in sympatry suggests dietary niche partitioning between these two species. In contrast, the high similarity of the trophic niches of P. austriacus and P. macrobullaris, associated with a typical parapatric distribution, indicates competitive exclusion. The best conservation measures are preservation and restoration of habitats offering a high abundance of moths, the major prey of the three Plecotus species.     

Differential diameter-size effects of forest management on tree species richness and community structure: implications for conservation

In this paper we tested the hypothesis that logging effects in the adult tree community reverberate upon the regeneration contingent. We examined the differences on the tree community between forest reserves and 10 year-old logged areas in the Yucatan Peninsula. We used a paired design in three independent sites to estimate the effects of logging on tree species richness, diversity, composition and structure. Analyses were conducted differentiating individuals of four diameter-size classes: 1–5, 5–10, 10–25, and >25 cm DBH. We found out that there were differential effects by size. Species richness in the smaller and larger diameter-size classes was significantly lower in logged areas. Floristic composition was also different between logged and unlogged areas, with a trend towards more secondary forest associated species and less primary forest associated species in logged areas, and a higher density of species represented by a single individual in unlogged reserves. In terms of structure, trees DBH <10 cm, lianas, and re-sprouting stumps were more abundant in logged areas. Our findings suggest that 10 years after logging, harvested areas show alterations in structure, and potentially a reduction in species richness. We suggest that to make timber extraction and forest conservation compatible at this site, it is necessary to gain a better understanding of the ecology and regeneration requirements of the less abundant species, and to assess whether current logging practices might hinder their permanence in the study area.     

Regeneration capacity of oceanic-montane liverworts: implications for community distribution and conservation

Abstract

Scotland’s mountains are home to a rare and unique liverwort community, ‘the oceanic-montane liverwort-rich heath’, but its component species are absent from regions where they could potentially thrive. Many biological characteristics of these species are unknown, making it impossible to explain the reasons for their rarity; however, they have not been observed to produce sporophytes within Britain. We use ex situ cultivation of whole liverworts and fragments, and in situ cultivation of fragments, to assess the growth rate and the potential for vegetative reproduction of several species. Most of the species grew from both fragments and as whole plants, indicating that the rarity of the liverwort heath is not due to poor powers of regeneration. We propose that growth rate and the potential to regenerate from fragments are important factors structuring the liverwort heath community, at least locally. Furthermore, this study demonstrates that there is potential for ex situ conservation of rare liverwort species, in situ enhancement of existing populations, and creation of new ones.     

Measurement and mapping of avian diversity in southern Africa: implications for conservation planning

The potential and problems of using species diversity information, derived from the Southern African Bird Atlas Project (SABAP), are examined. Atlas data were analysed and the problem of uneven sampling effort was ameliorated through an application of an index of diversity. Maps of diversity for various suites of species are considered in relation to their implications for conservation planning. An approach to the identification of high-priority areas for conservation, based on an index of diversity, is described and called the Compatible Sets Approach. Birds in the grassland biome are used to illustrate the principles of the approach.     

Relationships between plant diversity,vegetation cover,and site conditions: implications for grassland conservation in the Greater Caucasus

Overgrazing, land use abandonment and increasing recreational activities have altered the vegetation of high-montane and subalpine grassland of the Caucasus. The failure of previous restoration efforts with unsuitable and exotic plant species indicates the need for information on the present vegetation and in which way it might change. Within the Greater Caucasus, we have described and quantified the mountain grassland which develops under characteristic overgrazed and eroded site conditions. Further, we have proposed potential native plant species for revegetation to restore and conserve valuable mountain grassland habitats. We used non-metric dimensional scaling ordination and cluster comparison of functional plant groups to describe a gradient of grassland vegetation cover. For our study region, we identified four major vegetation types with increasing occurrence of ruderal pasture weeds and tall herb vegetation on abandoned hay meadows within the subalpine zone. Within high-montane grassland a decline of plant diversity can be observed on sites of reduced vegetation cover. Due to a low potential of the grassland ecosystem to balance further vegetation cover damage, the long-term loss of diverse habitats can be expected. We conclude with management recommendations to prevent erosion and habitat loss of precious mountain grasslands.     

Moth species richness,abundance and diversity in fragmented urban woodlands: implications for conservation and management strategies

Urban expansion threatens global biodiversity through the destruction of natural and semi-natural habitats and increased levels of disturbance. Whilst woodlands in urban areas may reduce the impact of urbanisation on biodiversity, they are often subject to under or over-management and consist of small, fragmented patches which may be isolated. Effective management strategies for urban woodland require an understanding of the ecology and habitat requirements of all relevant taxa. Yet, little is known of how invertebrate, and in particular moth, assemblages utilise urban woodland despite being commonly found within the urban landscape. Here we show that the abundance, species richness, and species diversity of moth assemblages found within urban woodlands are determined by woodland vegetation character, patch configuration and the surrounding landscape. In general, mature broadleaved woodlands supported the highest abundance and diversity of moths. Large compact woodlands with proportionally less edge exposed to the surrounding matrix were associated with higher moth abundance than small complex woodlands. Woodland vegetation characteristics were more important than the surrounding landscape, suggesting that management at a local scale to ensure provision of good quality habitat may be relatively more important for moth populations than improving habitat connectivity across the urban matrix. Our results show that the planting of broadleaved woodlands, retaining mature trees and minimising woodland fragmentation will be beneficial for moth assemblages.     

Floristic and ecological diversity of Ranunculus aquatic habitats in the sub-Atlantic range: implications for conservation

Ranunculus communities have been identified by the European Community Directive on Conservation of Natural and Semi-Natural Habitats as a key habitat in need of protection. The ecological requirements and floristic composition of three Ranunculus communities were investigated in North-Eastern France. We also aimed to determine the relationships between environmental parameters, Ranunculus abundance and species richness. R. fluitans communities clearly differed from the other communities by a higher evenness and species richness and by the occurrence of specific species. In contrast, R. penicillatus and R. peltatus communities displayed similar floristic content. Three different sub-associations were however identified within these communities. If alkalinity was determinant in isolating R. fluitans communities from the other stretches, the ecological ranges of the three communities strongly overlapped while considering parameters linked with other resources or with physical constraints. Further, no significant correlations were highlighted between environmental parameters, Ranunculus abundance and species richness. With respect to conservation, these observations may indicate the particular difficulty in defining each Ranunculus habitat on a European scale, and identify several key points which need to be taken into account when evaluating their status.     

Effects of topography on rainforest tree community structure and diversity in American Samoa, and implications for frugivore and nectarivore populations

Aim We investigated the spatial variation of rainforest tree community structure and composition to determine if forest structure and diversity varied as a function of topography; and in turn if this could influence patterns of habitat use by native forest birds and pteropodid bats. Location The study was undertaken on the island of Tutuila, American Samoa, located in the South Pacific Ocean. Methods All trees ≥10 cm diameter were censused in sixty 200 m² plots in ridge, slope and valley forest across the island of Tutuila. Results Forest structure varied significantly across topographical space. Ridge forest was shortest and had the highest stem densities, and valley forest was tallest with the fewest stems per unit area. Species richness was highest on ridges, and slope and valley forest were more similar in composition with each other than they were with ridge forest. Of the fifty-two tree species encountered in the plots, nine showed a statistical affiliation to one of the three topographical positions. Main conclusions We explain patterns of forest structure and diversity in the context of chronic and catastrophic disturbances. Higher stem densities in ridge forest suggested a higher degree of disturbance on ridges, and this was supported by the fact that the height/diameter ratio of the forest was lowest on ridges, which indicated wind-cropping. We hypothesize the potential effects of topographical variation and known phenological patterns on wildlife abundances. We predict that flowering episodes of ridge-affiliated, bird-visited species (particularly Syzygium inophylloides (A. Gray) C. Muell.; Myrtaceae) will concentrate honeyeater densities on ridges, and that fruiting of the tree Canarium vitiense A. Gray (Burseraceae) could localize populations of the Pacific pigeon (Ducula pacifica). Overall (i.e. net) bat foraging patterns are unlikely to be affected by either flowering or fruiting events. Most of the tree species on Tutuila are generalist in their demographic patterns, and the island is depauperate in wildlife fauna; the evolutionary and conservation implications are discussed. We conclude with the argument that conservation of vertebrate species is essential to maintain the current generalist demographic patterns of Samoan trees.     

Obligate groundwater fauna of France: diversity patterns and conservation implications

We examined taxonomic and geographic patterns of the obligate groundwater fauna (i.e. stygobiotic fauna) by assembling in a distributional data base all species occurrences reported from France since 1805. A simulated annealing algorithm was used to identify conservation targets. Until the 60s, biological surveys were restricted to caves but the proportion of sampling sites in unconsolidated sediments increased from 1 to 16% over the last 40 years. A total of 380 species and subspecies in 40 families were collected, 70% of which being restricted to France. As observed in other temperate regions, the stygobiotic fauna was dominated by crustaceans (65% of species) and molluscs (22%). The cumulative number of species did not level off over time, clearly showing that biodiversity was underestimated. Temporal trends in the cumulative number of obligate groundwater and surface water species suggested that groundwater comprised more crustaceans than surface freshwater. Endemism was high although the geographic range size of species increased as distributional data accumulated. Of 380 species, 156 were known from a single 400-km² cell, among which 73% were located in the southern third of France. The distribution map of species richness changed dramatically over time, indicating that the location of richness hotspots was sensitive to sampling effort. Less than 2% of the French landscape was needed to capture 60% of known species. Thus, a large proportion of species could be protected by focusing habitat conservation efforts on a few complementary species-rich aquifers located in distinct regions.