Woody species distribution across a savanna-dry forest soil gradient in the Brazilian Cerrado

Although richness and distribution of woody species in the Cerrado physiognomies have been extensively studied, the shifts of woody species from savanna physiognomies to dry forests have not yet been addressed. Here, we investigate the effect of soil physical-chemical traits on the woody species turnover between adjacent cerrado stricto sensu and dry forest physiognomies. Woody species were surveyed, and soil and topographic variables measured, in 30 10×40 m plots systematically distributed, with 15 plots in each physiognomy. We found a spatially structured distribution of woody species, and differences of soil traits between cerrado stricto sensu and dry forest areas, mainly related to the aluminum saturation, base saturation, and available phosphorus. Aluminum saturation increased toward the savanna area, while base saturation increased toward the dry forest. Most woody species predominated in one physiognomy, such as Callisthene major in the cerrado stricto sensu and Anadenanthera colubrina in the dry forest. Only 20% of the species were widely distributed across both physiognomies or, not often, restricted to the intermediary values of the soil gradient. General results indicate that contrasting soil traits between cerrado stricto sensu and dry forest produce a strongly spatially organized and sharp transition in terms of species distribution between these physiognomies.

The effect of mainland dynamics on data and parameter estimates in island biogeography

Understanding macroevolution on islands requires knowledge of the closest relatives of island species on the mainland. The evolutionary relationships between island and mainland species can be reconstructed using phylogenies, to which models can be fitted to understand the dynamical processes of colonisation and diversification. But how much information on the mainland is needed to gain insight into macroevolution on islands? Here we first test whether species turnover on the mainland and incomplete mainland sampling leave recognisable signatures in community phylogenetic data. We find predictable phylogenetic patterns: colonisation times become older and the perceived proportion of endemic species increases as mainland turnover and incomplete knowledge increase. We then analyse the influence of these factors on the inference performance of the island biogeography model DAISIE, a whole-island community phylogenetic model that assumes that mainland species do not diversify, and that the mainland is fully sampled in the phylogeny. We find that colonisation and diversification rate are estimated with little bias in the presence of mainland extinction and incomplete sampling. By contrast, the rate of anagenesis is overestimated under high levels of mainland extinction and incomplete sampling, because these increase the perceived level of island endemism. We conclude that community-wide phylogenetic and endemism datasets of island species carry a signature of mainland extinction and sampling. The robustness of parameter estimates suggests that island diversification and colonisation can be studied even with limited knowledge of mainland dynamics.

Unrecognized Ant Megadiversity in Monsoonal Australia: Diversity and Its Distribution in the Hyperdiverse Monomorium nigrius Forel Group

We document diversity and its distribution within the hyperdiverse Monomorium nigrius Forel group of the Australian monsoonal tropics, an unrecognized global centre of ant diversity. The group includes a single described species, but several distinct morphotypes each with multiple clearly recognizable taxa are known. Our analysis is based on 401 CO1-sequenced specimens collected from throughout the Australian mainland but primarily in the monsoonal north and particularly from four bioregions: the Top End (northern third) of the Northern Territory (NT), the Sturt Plateau region of central NT, the Kimberley region of far northern Western Australia, and far North Queensland. Clade structure in the CO1 tree is highly congruent with the general morphotypes, although most morphotypes occur in multiple clades and are therefore shown as polyphyletic. We recognize 97 species among our sequenced specimens, and this is generally consistent (if not somewhat conservative) with PTP analyses of CO1 clustering. Species turnover is extremely high both within and among bioregions in monsoonal Australia, and the monsoonal fauna is highly distinct from that in southern Australia. We estimate that the M. nigrius group contains well over 200 species in monsoonal Australia, and 300 species overall. Our study provides further evidence that monsoonal Australia should be recognized as a global centre of ant diversity.

Silvopastoral and conventional management of extensive livestock and the diversity of bats in fragments of tropical dry forest in Córdoba, Colombia

The establishment of extensive livestock systems in the Colombian Caribbean Region has historically generated a strong loss of the tropical dry forest (TDF) with negative effects on biodiversity. Currently, the implementation of silvopastoral systems (SPS) has been proposed with strategy to curb the loss of biodiversity caused by the conventional management system (CS). The objective was to evaluate the effect of SPS and CS of extensive livestock on the assemblage of bats associated with fragments of TDF. During a continuous year and a sampling effort of 30,240 h-net/night, the structure and composition of bat assemblage between SPS and CS were compared. 2788 bats belonging to six families, 23 genera, and 39 species were captured. The Phyllostomidae family presented the highest species richness (S = 30), with the greatest abundance in the Stenodermatinae subfamily (n = 1543). Bat assemblage in the SPS fragments was more equitable; and the relative abundance per species, per genera, and per foraging guilds was also significantly higher. The capture success showed significant variations between the climatic seasons (dry and rainy). The rate of species turnover was higher in the CS fragments. The species Artibeus planirostris, Artibeus lituratus, Carollia perspicillata, Carollia castanea, Phyllostomus discolor, Dermanura phaeotis, Uroderma convexum, Glossophaga soricina, C. brevicauda, and Sturnira lilium accounted for 92% of the captures. In conclusion, frugivorous bats were more abundant in the SPS, type of extensive livestock management that can generate greater temporal stability of bat assemblage. This research provides the first scientific evidence of the positive effect of silvopastoral management on the diversity of bats in tropical dry forest areas of the Colombian Caribbean region.

Turnover of Lecanoroid Mycobionts and Their Trebouxia Photobionts Along an Elevation Gradient in Bolivia Highlights the Role of Environment in Structuring the Lichen Symbiosis

Shifts in climate along elevation gradients structure mycobiont–photobiont associations in lichens. We obtained mycobiont (lecanoroid Lecanoraceae) and photobiont (Trebouxia alga) DNA sequences from 89 lichen thalli collected in Bolivia from a ca. 4,700 m elevation gradient encompassing diverse natural communities and environmental conditions. The molecular dataset included six mycobiont loci (ITS, nrLSU, mtSSU, RPB1, RPB2, and MCM7) and two photobiont loci (ITS, rbcL); we designed new primers to amplify Lecanoraceae RPB1 and RPB2 with a nested PCR approach. Mycobionts belonged to Lecanora s.lat., Bryonora, Myriolecis, Protoparmeliopsis, the “Lecanora” polytropa group, and the “L.” saligna group. All of these clades except for Lecanora s.lat. occurred only at high elevation. No single species of Lecanoraceae was present along the entire elevation gradient, and individual clades were restricted to a subset of the gradient. Most Lecanoraceae samples represent species which have not previously been sequenced. Trebouxia clade C, which has not previously been recorded in association with species of Lecanoraceae, predominates at low- to mid-elevation sites. Photobionts from Trebouxia clade I occur at the upper extent of mid-elevation forest and at some open, high-elevation sites, while Trebouxia clades A and S dominate open habitats at high elevation. We did not find Trebouxia clade D. Several putative new species were found in Trebouxia clades A, C, and I. These included one putative species in clade A associated with Myriolecis species growing on limestone at high elevation and a novel lineage sister to the rest of clade C associated with Lecanora on bark in low-elevation grassland. Three different kinds of photobiont switching were observed, with certain mycobiont species associating with Trebouxia from different major clades, species within a major clade, or haplotypes within a species. Lecanoraceae mycobionts and Trebouxia photobionts exhibit species turnover along the elevation gradient, but with each partner having a different elevation threshold at which the community shifts completely. A phylogenetically defined sampling of a single diverse family of lichen-forming fungi may be sufficient to document regional patterns of Trebouxia diversity and distribution.

Abandonment of cultural landscapes: butterfly communities track the advance of forest over grasslands

Rural landscapes in Europe have suffered considerable land-use change in the last 50 years, with agricultural intensification in western regions and land abandonment in eastern and southern regions. The negative impacts of agricultural intensification on butterflies and other insects in western Europe have been well studied. However, less is known about the impacts of abandonment on mountain and humid areas of eastern and southern Europe, where landscapes have remained more natural. We sampled butterfly communities in the Picos de Europa National Park (Spain), a region which is undergoing a process of rural abandonment. 19 hay meadows with different periods of abandonment were studied (long-term 18 years or mid-term abandoned, 3–7 years) and compared to meadows continuously managed in a traditional way. We examined how local meadow characteristics and landscape variables affected butterfly community response to abandonment. Butterfly communities were affected by abandonment, with an overall increase in the density of individuals in the long term. Community composition appears to undergo major change over time, with a species turnover of around 50% in the first few years of abandonment, rising to around 70% after 18 years of abandonment. There was a tendency for species with higher preference for closed habitats to increase their densities as time since abandonment proceeded. Landscape variables had a major impact on butterfly communities, stronger than the effect of meadow management. Community preference for closed habitats was associated with higher forest cover in the surroundings of the meadows, but heterogeneous landscapes (in their composition or configuration) mitigated this effect. Implications for insect conservation Our findings suggest that we should ensure that communities have time to react to the diverse stressors imposed by global change. Facilitating survival to all kinds of functional and taxonomic groups implies promoting landscape heterogeneity and connectivity.

Variation of Small and Large Wild Bee Communities Under Honeybee Pressure in Highly Diverse Natural Habitats

During the study, the honeybee effects on wild bees were tested and hypothesized that smaller distances from beehives will increase competitions between honeybees and wild bees, while greater distances will have a deleterious effect on competition. The impact on species richness and diversity was tested with distances from beehives, considering that this may differ when large and small wild bee species are considered separately. Altogether 158 species and 13,164 individuals were collected, from which 72% (9,542 individuals) were Apis mellifera. High variation in abundances was detected from one year to another, and the species turnover by sites was 67% in site A, 66% in site V, and 63% in site F. This last one was the site with the previous contact with honeybees. Considering distances from beehives, significant decreases in small bee species diversity were detected from one year to another at each distance except site F, 250 m from hives. The changes in species diversity and community structure of small bee species are detected from one year to another.

Taxonomic Dependency of Beta Diversity for Bacteria, Archaea and Fungi in a Semi-Arid Lake

Microbial beta diversity has been recently studied along the water depth in aquatic ecosystems, however its turnover and nestedness components remain elusive especially for multiple taxonomic groups. Based on the beta diversity partitioning developed by Baselga and Local Contributions to Beta Diversity (LCBD) partitioning by Legendre, we examined the water-depth variations in beta diversity components of bacteria, archaea and fungi in surface sediments of Hulun Lake, a semi-arid lake in northern China, and further explored the relative importance of environmental drivers underlying their patterns. We found that the relative abundances of Proteobacteria, Chloroflexi, Euryarchaeota and Rozellomycota increased towards deep water, while Acidobacteria, Parvarchaeota and Chytridiomycota decreased. For bacteria and archaea, there were significant (P < 0.05) decreasing water-depth patterns for LCBD and LCBDRepl (i.e., species replacement), while increasing patterns for total beta diversity and turnover, implying that total beta diversity and LCBD were dominated by species turnover or LCBDRepl. Further, bacteria showed a strong correlation with archaea regarding LCBD, total beta diversity and turnover. Such parallel patterns among bacteria and archaea were underpinned by similar ecological processes like environmental selection. Total beta diversity and turnover were largely affected by sediment total nitrogen, while LCBD and LCBDRepl were mainly constrained by water NO2−-N and NO3−-N. For fungal community variation, no significant patterns were observed, which may be due to different drivers like water nitrogen or phosphorus. Taken together, our findings provide compelling evidences for disentangling the underlying mechanisms of community variation in multiple aquatic microbial taxonomic groups.