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opencc-zeroNov 2022View details →

Lianas rapidly colonize early stages of tropical forests, presumably through leaf trait diversification

Questions: Ecological succession is the process during which ecosystems recover after disturbances. Studies investigating community re-assembly during tropical forest succession have rarely compared lianas to trees. We addressed two questions: (1) How do changes in stem density, total basal area, and species richness of lianas and trees compare throughout a secondary succession, and to what extent does the relative basal area of lianas change along a secondary succession? (2) How do the successional trajectories of functional community trait values of lianas and trees compare? Location: Yoko forest reserve, central Congo basin. Methods: Using univariate Bayesian modeling techniques, we analyzed differences in successional pathways between lianas and trees in terms of community structure, and functional assembly in a replicated chronosequence spanning from young to old-growth forests. Results: We found divergent structural trajectories between lianas and trees along the forest chronosequence. The stem density of lianas peaked at the intermediate stage, while that of trees almost linearly decreased from the early to late stages of succession. The basal area of lianas increased at a higher rate than that of trees, which translated into a marginal increase of liana relative basal area over succession. On the contrary, we observed a lower rate of increase in species richness for lianas than trees over succession. We found a progressive convergence in the responses of lianas and trees to changes with succession in terms of specific leaf area and leaf nitrogen content, but a diverging response in terms of leaf phosphorus content. These functional composition patterns most probably resulted from environmental filtering, induced by a change from nitrogen to phosphorus limitation as the succession progressed to mature forest. Conclusions: These findings underscore the rapid colonization of tropical forests by lianas after agricultural abandonment, presumably by deploying a more diverse leaf economic spectrum early in succession.

opencc-by-4.0Dec 2022View details →

Data for: Sub-tropical aerosols enhance tropical cloudiness – a remote aerosol-cloud lifetime effect

This data-set contains the data requires for the paper "Sub-tropical aerosols enhance tropical cloudiness – a remote aerosol-cloud lifetime effect" by Guy Dagan The variables containing *mean* in their name present time-average over the last 4-days of the simulations.

Data from: Season and herbivore defence trait mediate tri-trophic interactions in tropical rainforest

Bottom-up effects from host plants and top-down effects from predators on herbivore abundance and distribution vary with physical environment, plant chemistry, predator and herbivore trait and diversity. Tri-trophic interactions in tropical ecosystems may follow different patterns from temperate ecosystems due to differences in above abiotic and biotic conditions. We sampled leaf-chewing larvae of Lepidoptera (caterpillars) from a dominant host tree species in a seasonal rainforest in Southwest China. We reared out parasitoids and grouped herbivores based on their diet preferences, feeding habits, and defence mechanisms. We compared caterpillar abundance with leaf numbers ('bottom-up' effects) and parasitoid abundance ('top-down' effects) between different seasons and herbivore traits. We found bottom-up effects were stronger than top-down effects. Both bottom-up and top-down effects were stronger in the dry season than in the wet season, which were driven by polyphagous rare species and host plant phenology. Contrary to our predictions, herbivore traits did not influence differences in the bottom-up or top-down effects except for stronger top-down effects for shelter-builders. Our study shows season is the main predictor of the bottom-up and top-down effects in the tropics and highlights the complexity of these interactions.

opencc-by-4.0Sep 2022View details →

Assessing a megadiverse but poorly known community of fishes in a tropical mangrove estuary through environmental DNA (eDNA) metabarcoding

Biodiversity surveys are crucial for monitoring the status of threatened aquatic ecosystems, such as tropical estuaries and mangroves. Conventional monitoring methods are intrusive, time-consuming, substantially expensive, and often provide only rough estimates in complex habitats. An advanced monitoring approach, environmental DNA (eDNA) metabarcoding, is promising, although only few applications in tropical mangrove estuaries have been reported. In this study, we explore the advantages and limitations of an eDNA metabarcoding survey on the fish community of the Merbok Estuary (Peninsular Malaysia). COI and 12S eDNA metabarcoding assays collectively detected 178 species from 127 genera, 68 families, and 25 orders. Using this approach, significantly more species have been detected in the Merbok Estuary over the past decade (2010–2019) than in conventional surveys, including several species of conservation importance. However, we highlight three limitations: (1) in the absence of a comprehensive reference database the identities of several species are unresolved; (2) some of the previously documented specimen-based diversity was not captured by the current method, perhaps as a consequence of PCR primer specificity, and (3) the detection of non-resident species—stenohaline freshwater taxa (e.g., cyprinids, channids, osphronemids) and marine coral reef taxa (e.g., holocentrids, some syngnathids and sharks), not known to frequent estuaries, leading to the supposition that their DNA have drifted into the estuary through water movements. The community analysis revealed that fish diversity along the Merbok Estuary is not homogenous, with the upstream more diverse than further downstream. This could be due to the different landscapes or degree of anthropogenic influences along the estuary. In summary, we demonstrated the practicality of eDNA metabarcoding in assessing fish community and structure within a complex and rich tropical environment within a short sampling period. However, some limitations need to be considered and addressed to fully exploit the efficacy of this approach.

Patterns of ferns community assemblages in some Malaysian and Nigerian tropical forests

Research on fern ecology has gained attention in the last decade, yet there is a paucity of information on the comparison of ferns communities across continents. This study focused on comparing the ferns community assemblages in some tropical forests of Malaysia and Nigeria, thereby assessing the patterns of species richness (SR) and phylogenetic diversity(PD) in relation to the bioclimatic drivers across the continents. The diversity and taxonomic compositions of ferns were assessed using 180 plots of 10 m x 10 m in each country. The species richness and other diversity indices were determined using the combined forests data for each country and for the individual forests. Also, the phylogenetic diversity of the ferns was assessed using the genus-based molecular sequences downloaded from the GeneBank. The patterns of the ferns SR and PD in the two countries as driven by some bioclimatic factors were evaluated using the regression analysis. The observed and rarefied–extrapolated fern species richness is significantly higher in Malaysian forests than in Nigerian forests. Also, the other diversity indices are significantly higher in Malaysian forests except for the Shannon index which showed no significant difference between the two biogeographic regions. There is a very low similarity (7.41%) in the taxonomic composition of ferns between the two biogeographic areas, although the similarity in composition increased with increasing taxonomic levels (species: 7.41%, genus: 12.77%, family: 70.96%). Terrestrial and epiphytic ferns are more dominant than the other life forms in the two countries. The precipitation variables drive the phylogenetic structure of ferns in Nigeria whereas both precipitation and temperature variables drive the phylogenetic structure of ferns in Malaysia. This indicates that ferns assemblages in Nigeria and Malaysia are driven by both climatic variables. Besides, we also hypothesize that these observed differences could be due to other historical and evolutionary processes.

Biophysic and socioeconomic drivers of burned area and carbon emissions from fires in the Pantropical tropical dry forests

The global burned area declined by nearly one-quarter between 1998 and 2015. Drylands contain a large proportion of these global fires but there are important differences within the drylands, e.g., savannas and tropical dry forests (TDF). Savannas, a biome fire-prone and fire-adapted, have reduced the burned area, while the fire in the TDF is one of the most critical factors impacting biodiversity and carbon emissions. Moreover, under climate change scenarios TDF is expected to increase its current extent and raise the risk of fires. Despite regional and global scale effects, and the influence of this ecosystem on the global carbon cycle, little effort has been dedicated to studying the influence of climate (seasonality and extreme events) and socioeconomic conditions of fire regimen in TDF. Here we use the Global Fire Emissions Database and, climate and socioeconomic metrics to better understand long-term factors explaining the variation in burned area and biomass in TDF at the Pantropical scale. On average, fires affected 1.4% of the total TDF' area (60,208 km2) and burned 24.4% (259.6 Tg) of the global burned biomass annually at Pantropical scales. Climate modulators largely influence local and regional fire regimes. Inter-annual variation in fire regime is shaped by El Niño and La Niña. During El Niño and the forthcoming year of La Niña, there is an increment in extension (35.2 and 10.3%) and carbon emissions (42.9 and 10.6%). Socioeconomic indicators such as land management and population were modulators of the size of both, burned area and carbon emissions. Moreover, fires may reduce the capability to reach the target of "half protected species" in the globe, i.e., high-severity fires are recorded in ecoregions classified as nature could reach half protected. These observations may contribute to improving fire management.

opencc-by-4.0Dec 2022View details →

Effects of the environmental conditions and seasonality on a population survey of the Andean Condor Vultur gryphus in the tropical Andes

Script, datasets, and other supplementary material in Márquez-Alvis et al. 2023 PeerJ. Background: Among the New World vultures, the Andean Condor is considered one of the most culturally and ecologically important species. However, their populations are declining over their entire distributional range. In response, conservation strategies have been implemented in many countries to reverse the increasing extinction risk of this species. The initiatives rely on extensive population surveys to gather basic information necessary to implement policies and to intervene efficiently. Still, there is a need to standardize the surveys based on seasonality and suitable environmental conditions throughout the species distribution.  Here, we provide the first assessment of how daily temperature, rainfall, and seasonality influence surveys of Andean Condors on a communal roost in the central Peruvian Andes. Methods: Using an autoregressive generalized linear model, we associated environmental variables with visual surveys of adult and young condors at three different times of the day and three times a week between June 2014 and March 2015. Results: We found that both adults and young Andean Condors showed a threefold reduction in the use of the communal roost after the beginning of the rainy season. Colder and drier days (dry season) are preferable for surveying, as we expect the total number of condors using communal roosts to reduce under rainy (rainfall = -0.53 ± 0.16) and warmer days (temperature= - 0.04 ± 0.02) days. Therefore, the significant variation in the use of roosts across seasons and hours should be carefully accounted for in national surveys, at the risk of undermining the full potential of the communal roost surveys. Moreover, we also found a strong bias towards immatures (about 76%) in the adult:immature ratio and a remarkable absence of Andean Condors during the wet season. These results suggest that the species might be using other unknown communal roosts hierarchically. Such results provide key information for selecting priority areas for conservation and selecting the best time to survey this species in the tropical Andes. Finally, it may open a fruitful avenue for further research on the protection of the Andean Condor.

Genetic population dynamics of the critically endangered scalloped hammerhead shark (Sphyrna lewini) in the Eastern Tropical Pacific

The scalloped hammerhead shark, Sphyrna lewini, is a Critically Endangered, migratory species known for its tendency to form iconic and visually spectacular large aggregations. Herein, we investigated the population genetic dynamics of the scalloped hammerhead across much of its distribution in the Eastern Tropical Pacific (ETP), ranging from Costa Rica to Ecuador, focusing on young‐of‐the‐year animals from putative coastal nursery areas and adult females from seasonal aggregations that form in the northern Galápagos Islands. Nuclear microsatellites and partial mitochondrial control region sequences showed little evidence of population structure, suggesting that scalloped hammerheads in this ETP region comprise a single genetic stock. Galápagos aggregations of adults were not comprised of related individuals, suggesting that kinship does not play a role in the formation of the repeated, annual gatherings at these remote offshore locations. Despite high levels of fisheries exploitation of this species in the ETP, the adult scalloped hammerheads here showed greater genetic diversity compared with adult conspecifics from other parts of the species' global distribution. A phylogeographic analysis of available, globally sourced, mitochondrial control region sequence data (n = 1,818 sequences) revealed that scalloped hammerheads comprise three distinct matrilines corresponding to the three major world ocean basins, highlighting the need for conservation of these evolutionarily unique lineages. This study provides the first view of the genetic properties of a scalloped hammerhead aggregation, and the largest sample size‐based investigation of population structure and phylogeography of this species in the ETP to date.

Airborne eDNA documents a diverse and ecologically complex tropical bat and other mammal community

Environmental (e)DNA has rapidly become a powerful biomonitoring tool, particularly in aquatic ecosystems. This approach has not been as widely adopted in terrestrial communities where the methods of vertebrate eDNA collection have varied from the use of secondary collectors such as blood-feeding parasites and spider webs to washing surfaces of leaves and soil sampling. Recent studies have demonstrated the potential of direct collection of eDNA from air sampling, but none have tested how effective airborne eDNA sampling might be in a biodiverse environment. We used three prototype samplers to actively sample a mixed neotropical bat community in a partially controlled environment. We assess whether airborne eDNA can accurately characterize a high-diversity community with skewed abundances and to determine if filter design impacts DNA collection and taxonomic recovery. Our study provides evidence for the accuracy of airborne eDNA as a detection tool and highlights its potential for monitoring high-density, diverse assemblages such as bat roosts. Analysis of air samples recovered >91% of the species present and some limited relationship between species abundance and read count. Our data suggest this method can accurately depict a diverse mixed mammal community, particularly when the location is contained (e.g., a roost, den or burrow) but also highlights the potential for secondary transfer of eDNA material on clothing and equipment. Our results also demonstrate that simple, inexpensive, battery-operated homemade air samplers can collect an abundance of eDNA from the air, opening the opportunity for sampling in remote environments.

Data for: Plant roots fuel tropical soil animal communities

Belowground life relies on plant litter, while its linkage to living roots had long been understudied, and remains unknown in the tropics. Here, we analysed the response of 30 soil animal groups to root trenching and litter removal in rainforest and plantations in Sumatra, and found that roots are similarly important to soil fauna as litter. Trenching effects were stronger in soil than in litter, with an overall decrease in animal abundance in rainforest by 42% and in plantations by 30%. Litter removal little affected animals in soil layers, but decreased the total abundance by 60% in rainforest and rubber plantations but not in oil palm plantations. Litter and root effects on animal group abundances were explained by body size or vertical distribution. Our study quantifies principle carbon pathways in soil food webs under tropical land use, providing the basis for mechanistic modelling and ecosystem-friendly management of tropical soils.

opencc-by-4.0Dec 2014View details →

Fig. 110 in Comb-footed spiders (Araneae: Theridiidae) in the tropical rainforest of Xishuangbanna, Southwest China

Fig. 110. Locality of Xishuangbanna, from which the species of theridiid were collected.

Tropicalization shifts herbivore pressure from seagrass to rocky reef communities

Climate-driven species redistributions are reshuffling the composition of marine ecosystems. How these changes alter ecosystem functions, however, remains poorly understood. Here we examine how the impacts of herbivory change across a gradient of tropicalization in the Mediterranean Sea, which includes a steep climatic gradient and marked changes in plant nutritional quality and fish herbivore composition. We quantified individual feeding rates and behaviour of 755 fishes of the native Sarpa salpa, and non-native Siganus rivulatus and Siganus luridus. We measured herbivore and benthic assemblage composition across 20 sites along the gradient, spanning 30º of longitude and 8º of latitude. We coupled patterns in behaviour and composition with temperature measurements and nutrient concentrations to assess changes in herbivory under tropicalization. We found a transition in ecological impacts by fish herbivory across the Mediterranean from a predominance of seagrass herbivory in the west to a dominance of macroalgal herbivory in the east. Underlying this shift were changes in both individual feeding behaviour (i.e., food choice) and fish assemblage composition. The shift in feeding selectivity was consistent among temperate and warm-affiliated herbivores. Our findings suggest herbivory can contribute to the increased vulnerability of seaweed communities and reduced vulnerability of seagrass meadows in tropicalized ecosystems.

opencc-by-4.0Jan 2023View details →

Source Data for: Temperature, species identity and morphological traits predict carbonate excretion and mineralogy in tropical reef fishes

Source Data underlying figures of the paper "Temperature, species identity and morphological traits predict carbonate excretion and mineralogy in tropical reef fishes" by Mattia Ghilardi, Michael A. Salter, Valeriano Parravicini, Sebastian C. A. Ferse, Tim Rixen, Christian Wild, Matthias Birkicht, Chris T. Perry, Alex Berry, Rod W. Wilson, David Mouillot, Sonia Bejarano

Climate and microhabitat shape the prevalence of endozoochory in the seed rain of tropical montane forests

Endozoochory, the dispersal of seeds by animal ingestion, is the most dominant mode of seed dispersal in tropical forests and is a key process shaping current and future forest dynamics. However, it remains largely unknown how endozoochory is associated with environmental conditions at regional and local scales. Here, we investigated the effects of elevation, climate and microhabitat conditions on the proportion of endozoochorous plant species in the seed rain of the tropical Andes of southern Ecuador. Over one year, we measured seed rain in 162 seed traps on nine 1-ha forest plots located at 1000 m, 2000 m, and 3000 m a.s.l. We recorded climatic conditions (mean annual temperature and rainfall) in each plot and microhabitat conditions (leaf area index and soil moisture) adjacent to each seed trap. In total, we recorded 331,838 seeds belonging to 323 morphospecies. Overall, the proportion of endozoochorous species in the seed rain decreased with elevation. Relative biomass of endozoochorous species decreased with increasing rainfall, whereas the relative seed richness of endozoochorous species increased with increasing temperature and leaf area index. These findings suggest an interplay between climate factors and microhabitat conditions in shaping the importance of endozoochorous plant species in the seed rain of tropical montane forests. We conclude that changing climatic and microhabitat conditions are likely to cause changes in the dominant dispersal modes of plant communities which may trigger changes in current and future dynamics of tropical forests.

opencc-by-4.0Jan 2023View details →

Leaf decomposition, flammability and functional trait data for tropical swamp forest tree species

Decomposition and fire are major carbon pathways in many ecosystems, yet the contribution of species identity to these processes can be difficult to predict. Plant decomposability and flammability have usually been studied separately but could be linked through shared predictive traits. We explored how decomposability and flammability were related to each other and to key plant functional traits in a tropical swamp forest in Singapore. Full methodological details in situ decomposition experiment in Nee Soon freshwater swamp forest, Singapore, laboratory flammability experiment, and leaf functional trait measurements can be found in the published article and supporting information stated below. Nur E. B. Rahman, Stuart W. Smith, Weng Ngai Lam, Kwek Yan Chong, Matthias S. E. Chua, Pei Yun Teo, Daniel W. J. Lee, Shi Yu Phua, Cheryl Y. Aw, Janice S. H. Lee, David A. Wardle. Leaf decomposition and flammability are largely decoupled across species in a tropical swamp forest despite sharing some predictive leaf functional traits. New Phytologist In this data repository, we have uploaded the following decomposition, flammability and trait data as well as secondary data used in our statistical analyses to generate the findings presented in the paper. Specific datasets include the following: <ul> <li>litter_mass_loss.csv : raw data of leaf litterbag dry masses before and after 1 year in situ decomposition experiment in Nee Soon Swamp Forest</li> <li>flammability_leaf_temperature.csv : raw data of temperature recorded during flammability experiments of leaf litter and fresh leaves</li> <li>flammability_timings.csv : raw data of timings of flammability events, namely smouldering and pyrolysis recorded from video footage of flammability experiments</li> <li>senesced_leaf_dryweights_area.csv : senesced leaf raw data for calculating physical traits</li> <li>senesced_leaf_dryweights.csv: senesced leaf dry weights raw data</li> <li>freshtraits_measurements.csv: fresh leaf raw data for calculating physical traits</li> <li>decomposition_constants.csv: derived decomposition constants (k) for each species from the analysis of decomposition experiments.</li> <li>functional_traits_z_standardized.csv : all traits required for the analysis, consolidated following z-standardized transformation</li> <li>functional_traits_untransformed_decomposition_flammability.csv : all traits required for the analysis, untransformed (for back transforming axis labels) and species decomposition and flammability variables</li> </ul> Raw leaf litter mass loss and leaf flammability data are associated meta-data file explaining the column headers and variables. For all other datasets please refer to the paper and supporting information.

Successional and phenological effects on plant-floral visitor interaction networks of a tropical dry forest

1. Plant-pollinator interactions are fundamental to ecosystem functioning; however, the role that succession and phenology have on these interactions is poorly understood, particularly in endangered tropical ecosystems. In highly diverse ecosystems such as tropical dry forests (TDF), variation in water and food availability determines the life cycles of animal pollinators. Therefore, understanding patterns of flowering phenology and plant-pollinator interactions across seasons in successional environments is key to maintaining and restoring TDF. 2. We analysed the functional dynamics of plant-floral visitor interactions at the community level across a successional gradient in a Mexican TDF. We evaluated changes in the diversity of blooming plant species and floral visitors, phenological patterns, interaction network metrics, and beta diversity among early, intermediate, and late successional stages, between dry and rainy seasons. 3. We found a higher diversity of blooming plant species and a higher richness of animal species in the intermediate and late successional stages. Peak abundance of floral visitors overlapped with flowering peaks in the late successional stages, but this was not consistently the case in the early and intermediate stages. Plant-floral visitors networks differed in structure according to successional stage and season, but specialisation metrics were higher in late successional stages. Interaction networks were more dissimilar between dry and rainy seasons within successional stages than within seasons between successional stages, suggesting connectivity across successional sites during each season. In addition, closely related plant species do not share the same pollination systems in any successional stage. 4. Synthesis. Our results showed that plant-floral visitor interactions are dynamic and vary with flowering phenology and with successional changes in plant and animal diversity. Plant-floral visitor interactions were more diverse and specialised in the late successional stages. In the rainy season, differences in network structure among successional stages are due to interaction rewiring, while in the dry season, it is caused by species turnover. Our results demonstrate that seasonality plays a key role in community diversity and network structure and highlight the importance of conserving mature forests to ensure the maintenance of critical pollination interactions across all successional stages.

Tropical bat ectoparasitism in continuous versus fragmented forests: A gap analysis and preliminary meta-analysis

Tropical regions are experiencing rapid rates of forest fragmentation, which can have several effects on wildlife, including altered parasite dynamics. Bats are a useful host group to consider these effects of fragmentation because they are abundant in the tropics, serve important ecological roles, and harbour many parasites. Nevertheless, research on the effects of fragmentation on bat ectoparasites is still limited. To help guide ongoing and future research efforts, this study had two objectives: (1) conduct a gap analysis to characterize the state of currently available research on fragmentation effects on bat ectoparasites, and (2) conduct a preliminary meta-analysis to identify current trends. We systematically highlighted several research gaps: studies comparing the effects of fragmented versus continuous forests on ectoparasites are limited and have primarily been conducted in the Neotropics, with a focus on bats in the superfamily Noctilionidea (especially frugivorous phyllostomids). Our preliminary meta-analysis suggested that ectoparasite prevalence (but not the mean or variance in intensity) was higher in fragments than in continuous forests. Moreover, prevalence increased with increasing roost duration, and mean intensity was higher for bats with higher wing aspect ratios. Intensity variance was affected by an interaction between forest type and wing aspect ratio, such that variance increased for bats with high wing aspect ratios in continuous forests but decreased in fragments. These results suggest that fragmentation can shape aspects of bat ectoparasitism and could have implications for the ecology, health, and conservation of bats in fragmented landscapes. However, existing research gaps could bias our current understanding of habitat change and bat health, and future research should thus investigate these effects in the Paleotropics and with other bat families.

Datasets from: Local- and landscape-scale drivers of terrestrial herbaceous plant diversity along a tropical rainfall gradient in Western Ghats, India

This data set contains information on local- and landscape-level terrestrial herbaceous plant diversity and critical abiotic factors along a 36-km East-West transect in Mudumalai Tiger Reserve, Tamil Nadu India. Understory angiosperms with no above-ground wood (secondary cambial growth) were considered as herbaceous plants.

Global expansion of a solitary-social tropical spitting spider shaped by multiple long-distance dispersals

The spitting spider Scytodes fusca is well known species complex for its unusual hunting technique which involves spitting a venomous sticky silken substance over its prey. Previous studies supposed that S. fusca was native to Central and Southern America but had been expanded to the tropics of almost every continent. We aimed to test the hypothesis of a Neotropical origin for this spider followed by a secondary dispersal to other regions, and to discuss how population expansion occurred in the tropics was driven. We investigated the population structure and spatiotemporal biogeography of the species complex through a culmination of a 22-year comprehensive global sampling using the mitochondrial and nuclear loci (COI, 16S, 18S, 28S, H3 and ITS2). The S. fusca species complex is divided into two clades. One clade comprises the haplotypes from Australasian regions and a haplotype from Baja Peninsula, Mexico. The other is composed of the haplotypes from all analyzed regions including Asia, Australia, the Americas and Madagascar. The Americas and Madagascar populations exhibit a lower genetic diversity compared with the Australasian population, and both have different population demographic histories. The initial divergence within the species complex started during the early Miocene. Diversifications of both clades occurred during the late Miocene. One haplotype was recently and widely dispersed into Southeast Asia, South Asia, Australia, the Americas and Madagascar. Our results elucidate the global spread history of the S. fusca species complex, suggesting a Malay Archipelago origin, two expansion routes, and its multiple dispersals into the Americas that stem from a common native source population, as well as from Australia, Fiji, French Polynesia, or Turks and Caicos bridgeheads. Our data support that the expansion of the S. fusca species complex from Australasia to America and Madagascar was facilitated by long-distance jump dispersal events.

A new, disjunct species of Bahiana (Euphorbiaceae-Acalyphoideae): Phytogeographic connections between the seasonally dry tropical forests of Peru and Brazil, and a review of spinescence in the family

Bahiana is expanded from 1 to 2 species with the description of B. occidentalis K. Wurdack, sp. nov. as a new endemic of the seasonally dry tropical forests (SDTFs) of Peru. The disjunct distribution of Bahiana with populations of B. occidentalis on opposite sides of the Andes in northwestern Peru (Tumbes, San Martín) and B. pyriformis in eastern Brazil (Bahia) adds to the phytogeographic links among the widely scattered New World SDTFs. Although B. occidentalis remains imperfectly known due to lack of flowering collections, molecular phylogenetic results from four loci (plastid matK, rbcL, and trnL-F; and nuclear ITS) unite the two species as does gross vegetative morphology, notably their spinose stipules, and androecial structure. Spinescence in Euphorbiaceae was surveyed and found on vegetative organs in 25 genera, which mostly have modified sharp branch tips. Among New World taxa, spines that originate from stipule modifications only occur in Bahiana and Acidocroton, while the intrastipular spines of Philyra are of uncertain homologies.