SignificanceIdentifying and explaining regional differences in tropical forest dynamics, structure, diversity, and composition are critical for anticipating region-specific responses to global environmental change. Floristic classifications are of fundamental importance for these efforts. Here we provide a global tropical forest classification that is explicitly based on community evolutionary similarity, resulting in identification of five major tropical forest regions and their relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. African and American forests are grouped, reflecting their former western Gondwanan connection, while Indo-Pacific forests range from eastern Africa and Madagascar to Australia and the Pacific. The connection between northern-hemisphere Asian and American forests is confirmed, while Dry forests are identified as a single tropical biome.

ABSTRACT(Altitudinal heterogeneity in northern Atlantic Forest: a case study in southeastern Bahia, Brazil) Th e Atlantic Forest has a heterogeneity that is still largely unappreciated, especially that associated with altitudinal factors; this has rarely been examined in the northern extension of this biome. Th e study investigated the occurrence of variation in fl oristic composition, diversity, and vegetation structure at two altitudes in a remnant area of forest in southern Bahia state. A total of 0.5 ha of vegetation was sampled in fi ve separate plots established in a wet forest in the RPPN Serra Bonita, Bahia, Brazil. A total of 354 species belonging to 68 families were found, with Myrtaceae, Fabaceae, Rubiaceae and Lauraceae being the richest taxa. Th e two altitudinal sites showed signifi cant diff erences in density, basal area and structure. Th ere were notable changes in forest structure with increasing altitude, refl ected in higher densities of the understory and a reduction in species richness. Serra Bonita had high species diversity that was similar to other areas in Bahia, but higher than found in the Atlantic Forests of southeastern Brazil. Th e forest sections sampled were well preserved, as indicated by the abundance of woody vines, elevated basal area, and lack of evidence of signifi cant logging activities. Th e variation detected between the areas suggests the existence of abrupt structural modifi cations infl uenced not by edaphic factors but by rainfall diff erences, temperature variations, and by local barriers determined by the steep topography.

Ecological niche models (ENM) use the environmental variables associated with the currently known distribution of a species to model its ecological niche and project it into the geographic space. Widely used and misused, ENM has become a common tool for ecologists and decision-makers.Many ENM platforms have been developed over the years, first as standalone programs, later as packages within script-based programming languages and environments. The democratization of these programming tools and the advent of Open Science brought a growing concern regarding the reproducibility, transparency, robustness, portability, and interoperability in ENM workflows.ENM workflows have some core components that are replicated between projects. However, they have a large internal variation due to the variety of research questions and applications. Any ecological niche modeling platform should take into account this trade-off between stability and reproducibility on one hand, and flexibility and decision-making on the other.Here, we present modleR, a four-step workflow that wraps some of the common phases executed during an ecological niche model procedure. We have divided the process into (1) data setup, (2) model fitting and projection, (3) partition joining and (4) ensemble modeling (consensus between algorithms).modleR is highly adaptable and replicable depending on the user's needs and is open to deeper internal parametrization. It can be used as a testing platform due to its consistent folder structure and its capacity to control some sources of variation while changing others. It can be run in interactive local sessions and in high-performance or high-throughput computational (HPC/HTC) platforms and parallelized by species or algorithms. It can also communicate with other tools in the field, allowing the user to enter and exit the workflow at any phase, and execute complementary routines outside the package. Finally, it records metadata and session information at each step, ensuring reproducibility beyond the use of script-based applications.

21The increasing worldwide interest on the conservation of tropical forests 22 reflects the conversion of over 50% of their area into agricultural lands and other uses. 23Understanding the distribution of remaining biodiversity across agricultural landscapes 24 is an essential task to guide future conservation strategies. To understand the long-25 term effects of fragmentation on biodiversity, we investigated whether forest fragments 26 in southeastern Brazil are under a taxonomic homogenization or heterogenization 27 process. We estimated pre-deforestation species richness and composition based on 28 a Species Distribution Modelling approach, and compared them to the observed 29 patterns of α-and β-diversity. In particular, we asked (i) if changes in β-diversity reveal 30 convergence or divergence on species composition; (ii) if these changes are similar 31 between forest fragments in Strictly Protected Areas (SPAs) (n=20) and within private 32 lands (n=367) and in different regions of the state (West, Center, and Southeast). We 33 detected steep reductions in observed local species richness in relation to our modeled 34 predictions, and this was particularly true among forest fragments in non-protected 35 private lands. The higher observed β diversity indicated an overall biotic 36 heterogenization process, consistent with the idea that the originally diverse 37vegetation is now reduced to small and isolated patches, with unique disturbance 38 histories and impoverished communities derived from a large regional species pool. 39Since conservation of biodiversity extends beyond the boundaries of strictly Protected 40 Areas, we advocate forest fragments are valuable for conservation in agricultural 41 landscapes, with particular relevance for private lands, which represent the most 42 exposed and neglected share of what is left. 43 44

No abstract

No abstract

No abstract

No abstract