The role of climate and islands in species diversification and reproductive-mode evolution of Old World tree frogs

Large diversifications of species are known to occur unevenly across space and evolutionary lineages, but the relative importance of their driving mechanisms, such as climate, ecological opportunity and key evolutionary innovations (KEI), remains poorly understood. Here, we explore the remarkable diversification of rhacophorid frogs, which represent six percent of global amphibian diversity, utilize four distinct reproductive modes, and span a climatically variable area across mainland Asia, associated continental islands, and Africa. Using a complete species-level phylogeny, we find near-constant diversification rates but a highly uneven distribution of species richness. Montane regions on islands and some mainland regions have higher phylogenetic diversity and unique assemblages of taxa; we identify these as cool-wet refugia. Starting from a centre of origin, rhacophorids reached these distant refugia by adapting to new climatic conditions (‘niche evolution’-dominant), especially following the origin of KEIs such as terrestrial reproduction (in the Late Eocene) or by dispersal during periods of favourable climate (‘niche conservatism’-dominant).

By examining climate, geographical and phylogenetic data, the diversification and evolution of rhacophorid frogs is explored

Evolution of Dispersal, Habit, and Pollination in Africa Pushed Apocynaceae Diversification After the Eocene-Oligocene Climate Transition

Apocynaceae (the dogbane and milkweed family) is one of the ten largest flowering plant families, with approximately 5,350 species and diverse morphology and ecology, ranging from large trees and lianas that are emblematic of tropical rainforests, to herbs in temperate grasslands, to succulents in dry, open landscapes, and to vines in a wide variety of habitats. Despite a specialized and conservative basic floral architecture, Apocynaceae are hyperdiverse in flower size, corolla shape, and especially derived floral morphological features. These are mainly associated with the development of corolline and/or staminal coronas and a spectrum of integration of floral structures culminating with the formation of a gynostegium and pollinaria—specialized pollen dispersal units. To date, no detailed analysis has been conducted to estimate the origin and diversification of this lineage in space and time. Here, we use the most comprehensive time-calibrated phylogeny of Apocynaceae, which includes approximately 20% of the species covering all major lineages, and information on species number and distributions obtained from the most up-to-date monograph of the family to investigate the biogeographical history of the lineage and its diversification dynamics. South America, Africa, and Southeast Asia (potentially including Oceania), were recovered as the most likely ancestral area of extant Apocynaceae diversity; this tropical climatic belt in the equatorial region retained the oldest extant lineages and these three tropical regions likely represent museums of the family. Africa was confirmed as the cradle of pollinia-bearing lineages and the main source of Apocynaceae intercontinental dispersals. We detected 12 shifts toward accelerated species diversification, of which 11 were in the APSA clade (apocynoids, Periplocoideae, Secamonoideae, and Asclepiadoideae), eight of these in the pollinia-bearing lineages and six within Asclepiadoideae. Wind-dispersed comose seeds, climbing growth form, and pollinia appeared sequentially within the APSA clade and probably work synergistically in the occupation of drier and cooler habitats. Overall, we hypothesize that temporal patterns in diversification of Apocynaceae was mainly shaped by a sequence of morphological innovations that conferred higher capacity to disperse and establish in seasonal, unstable, and open habitats, which have expanded since the Eocene-Oligocene climate transition.

Spatial distribution and associated flora of Alcantarea nahoumii, a vulnerable endemic species to rocky outcrops of the Serra da Jibóia, Bahia, Brazil

Abstract The objective of this study was to characterize the spatial distribution pattern at different altitude gradientes as well as to investigate the flora associated with A. nahoumii, considered to be endemic and vulnerable. The study was carried out in Serra da Jibóia, Santa Teresinha, Bahia, Brazil. An inventory was conducted of Young and adult A. nahoumii specimens along with taxonomic identification and quantification of the associated species. The cover percentage of A. nahoumii, rock slope, organic matter percentage and exposed rock percentage were calculated, as well as the following phytosociological parameters: absolute density, relative density, absolute frequency, relative frequency, and dominance of A. nahoumii. For the spatial distribution, three indices were tested (Morisita, McGuinnes and Payandech). Canonical correspondence analysis was also applied to test the association of the environmental variables with the species in the community. A total of 1,660 individuals were encountered and classified according to taxonomy in 17 families, 25 genera and 28 species. The spatial distribution pattern of the A. nahoumii population is aggregate. The results demonstrate that the population structure of A. nahoumii is stable, but events such as fires and extractive exploitation make the species vulnerable, along with the other species that inhabit the area.

Plant Biodiversity Drivers in Brazilian Campos Rupestres: Insights from Phylogenetic Structure

Old, climate-buffered infertile landscapes (Ocbils) have attracted increasing levels of interest in recent years because of their exceptionally diverse plant communities. Brazil's campos rupestres (rupestrian grasslands) are home to almost 15% of Brazil's native flora in less than 0.8% of Brazil's territory: an ideal study system for exploring variation in floristic diversity and phylogenetic structure in sites differing in geology and phytophysiognomy. We found significant differences in floristic diversity and phylogenetic structure across a range of study sites encompassing open vegetation and forest on quartzite (FQ) and on ironstone substrates, commonly termed canga. Substrate and physiognomy were key in structuring floristic diversity in the Espinhaço and physiognomy was more important than substrate in structuring phylogenetic diversity, with neither substrate nor its interaction with physiognomy accounting for significant variation in phylogenetic structure. Phylogenetic clustering was significant in open vegetation on both canga and quartzite, reflecting the potential role of environmental filtering in these exposed montane communities adapted to multiple environmental stressors. In forest communities, phylogenetic clustering was significant only at relatively deep nodes of the phylogeny in FQ while no significant phylogenetic clustering was detected across forest on canga (FC), which may be attributable to proximity to the megadiverse Atlantic forest biome and/or comparatively benign environmental conditions in FC with relatively deep, nutrient-rich soils and access to edaphic water reliable in comparison to those for open vegetation on canga and open or forest communities on quartzite. Clades representing relatively old lineages are significantly over-represented in campos rupestres on quartzite, consistent with the Gondwanan Heritage Hypothesis of Ocbil theory. In contrast, forested sites on canga are recognized as Yodfels. To be effective, conservation measures must take account of the distinct communities which are encompassed within the broad term campos rupestres, and the differing vulnerabilities of Ocbils and Yodfels.

Flora of Brazil Online: Can Brazil's botanists achieve their 2020 vision?

Abstract This paper seeks to provide an assessment of the prospects of delivering an online Flora of Brazil by 2020. Our approach is to evaluate the nature and extent of documentation of the Brazilian flora over the past 15 years before exploring whether existing botanical documentation and capacity is sufficient to support the production of a complete Flora over a five-year period. We address the following 'headline' questions: Has a high proportion of Brazilian species been described? Are collection densities sufficient to underpin a national Flora? Is there sufficient botanical expertise available to execute such a big project over a five-year period? Are there current taxonomic treatments that support the development of a national Flora? The results obtained show that the proportion of the flora estimated to have been described is high enough to be confident that those preparing Flora treatments will not be overwhelmed by the numbers of species new to science requiring description; the national average of 1.08 specimens per km2 is significant; relevant taxonomic treatments with a variety of different scopes and geographic scales are available; and, finally the botanical expertise available is demonstrated by the results presented in the List of Species of the Flora of Brasil.