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Copyright of Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background Tribe Fabeae comprises about 380 legume species, including some of the most ancient and important crops like lentil, pea, and broad bean. Breeding efforts in legume crops rely on a detailed knowledge of closest wild relatives and geographic origin. Relationships within the tribe, however, are incompletely known and previous molecular results conflicted with the traditional morphology-based classification. Here we analyse the systematics, biogeography, and character evolution in the tribe based on plastid and nuclear DNA sequences. Results Phylogenetic analyses including c. 70% of the species in the tribe show that the genera Vicia and Lathyrus in their current circumscription are not monophyletic: Pisum and Vavilovia are nested in Lathyrus, the genus Lens is nested in Vicia. A small, well-supported clade including Vicia hirsuta, V. sylvatica, and some Mediterranean endemics, is the sister group to all remaining species in the tribe. Fabeae originated in the East Mediterranean region in the Miocene (23–16 million years ago (Ma)) and spread at least 39 times into Eurasia, seven times to the Americas, twice to tropical Africa and four times to Macaronesia. Broad bean (V. faba) and its sister V. paucijuga originated in Asia and might be sister to V. oroboides. Lentil (Lens culinaris ssp. culinaris) is of Mediterranean origin and together with eight very close relatives forms a clade that is nested in the core Vicia, where it evolved c. 14 Ma. The Pisum clade is nested in Lathyrus in a grade with the Mediterranean L. gloeosperma, L. neurolobus, and L. nissolia. The extinct Azorean endemic V. dennesiana belongs in section Cracca and is nested among Mediterranean species. According to our ancestral character state reconstruction results, ancestors of Fabeae had a basic chromosome number of 2n=14, an annual life form, and evenly hairy, dorsiventrally compressed styles. Conclusions Fabeae evolved in the Eastern Mediterranean in the middle Miocene and spread from there across Eurasia, into Tropical Africa, and at least seven times to the Americas. The middle-Atlantic islands were colonized four times but apparently did not serve as stepping-stones for Atlantic crossings. Long-distance dispersal events are relatively common in Fabeae (seven per ten million years). Current generic and infrageneric circumscriptions in Fabeae do not reflect monophyletic groups and should be revised. Suggestions for generic level delimitation are offered.

Societal Impact Statement: Understanding of tropical forests has been revolutionized by monitoring in permanent plots. Data from global plot networks have transformed our knowledge of forests' diversity, function, contribution to global biogeochemical cycles, and sensitivity to climate change. Monitoring has thus far been concentrated in rain forests. Despite increasing appreciation of their threatened status, biodiversity, and importance to the global carbon cycle, monitoring in tropical dry forests is still in its infancy. We provide a protocol for permanent monitoring plots in tropical dry forests. Expanding monitoring into dry biomes is critical for overcoming the linked challenges of climate change, land use change, and the biodiversity crisis. [ABSTRACT FROM AUTHOR]

Aim: In savannas, a grass‐dominated ground layer is key to ecosystem function via grass–fire feedbacks that maintain open ecosystems. With woody encroachment, tree density increases, thereby decreasing light in the ground layer and potentially altering ecosystem function. We investigated how light availability can filter individual grass species distributions and whether different functional traits are associated with response to a shade gradient in a landscape experiencing woody encroachment. Location: Savanna–forest mosaic in the Cerrado domain, southeastern Brazil. Methods: Along an encroachment gradient of increasing tree leaf area index (LAI) and shade, we determined how changing light availability alters grass diversity and ground layer structure relative to grass cover and grass functional traits (photosynthetic pathway, underground storage organs, bud protection and traits related to grass shape, size and leaf dimensions). Results: Increasing shade led to a decrease in grass cover and grass species richness, and also compositional and functional changes. We found that where tree LAI reached 1, grass cover was reduced by 50% and species richness by 30%. While C4 grass species abundances decreased with increasing shade, the opposite pattern was true for C3 grasses. There were only small differences in light preferences among C4 subtypes, with phosphoenolpyruvate carboxykinase (PCK) species tolerating slightly more shaded conditions. Persistence of some C4 species under more shaded conditions was possible, likely due to an ability to store starch reserves via underground storage organs. Conclusions: Woody encroachment changes diversity and structure of the grassy layer that is critical to the functioning of savanna ecosystems, highlighting the dependence of the diverse grass layer on open and sunny conditions. Our results suggest a threshold of tree cover close to LAI ≈ 1 as being critical to cerrado grassy layer conservation. [ABSTRACT FROM AUTHOR]

A monophyletic pantropical group of papilionoid legumes, here referred to as the 'dalbergioid' legumes, is circumscribed to include all genera previously referred to the tribes Aeschynomeneae and Adesmieae, the subtribe Bryinae of the Desmodieae, and tribe Dalbergieae except Andira, Hymenolobium, Vatairea, and Vataireopsis. This previously undetected group was discovered with phylogenetic analysis of DNA sequences from the chloroplast trnK (including matK) and trnL introns, and the nuclear ribosomal 5.8S and flanking internal transcribed spacers 1 and 2. All dalbergioids belong to one of three well-supported subclades, the Adesmia, Dalbergia, and Pterocarpus clades. The dalbergioid clade and its three main subclades are cryptic in the sense that they are genetically distinct but poorly, if at all, distinguished by nonmolecular data. Traditionally important taxonomic characters, such as arborescent habit, free stamens, and lomented pods, do not provide support for the major clades identified by the molecular analysis. Short shoots, glandular-based trichomes, bilabiate calyces, and aeschynomenoid root nodules, in contrast, are better indicators of relationship at this hierarchical level. The discovery of the dalbergioid clade prompted a re-analysis of root nodule structure and the subsequent finding that the aeschynomenoid root nodule is synapomorphic for the dalbergioids. Key words: aeschynomenoid nodule; dalbergioid legumes; Fabaceae; papilionoid legumes; root nodule.

Background and Aims Geoxyles, a distinctive feature of Afrotropical savannas and grasslands, survive recurrent disturbances by resprouting subshrub branches from large below-ground woody structures. Underground trees are a type of geoxyle that independently evolved within woody genera of at least 40 plant families in Africa. The environmental limits and determinants of underground tree biogeography are poorly understood, with the relative influence of frost and fire debated in particular. We aim to quantify variability in the niche of underground tree species relative to their taller, woody tree/shrub congeners. Methods Using occurrence records of four Afrotropical genera, Parinari (Chrysobalanaceae), Ozoroa (Anacardiaceae), Syzygium (Myrtaceae) and Lannea (Anacardiaceae), and environmental data of nine climate and disturbance variables, the biogeography and niche of underground trees are compared with their open and closed ecosystem congeners. Key Results Along multiple environmental gradients and in a multidimensional environmental space, underground trees inhabit significantly distinct and extreme environments relative to open and closed ecosystem congeners. Niche overlap is low among underground trees and their congeners, and also among underground trees of the four genera. Of the study taxa, Parinari underground trees inhabit hotter, drier and more seasonal environments where herbivory pressure is greatest. Ozoroa underground trees occupy relatively more fire-prone environments, while Syzygium underground trees sustain the highest frost frequency and occur in relatively wetter conditions with seasonal waterlogging. Lannea underground trees are associated with the lowest temperatures, highest precipitation, and varying exposure to disturbance. Conclusions While underground trees exhibit repeated convergent evolution, varied environments shape the ecology and biogeography of this iconic plant functional group. The multiplicity of extreme environments related to fire, frost, herbivory and waterlogging that different underground tree taxa occupy, and the distinctiveness of these environments, should be recognized in the management of African grassy ecosystems. [ABSTRACT FROM AUTHOR]

Ecology, geography, morphology, and a combined phylogenetic analysis of DNA sequence variation support the recognition of the new species Luetzelburgia jacana (Leguminosae, Papilionoideae, vataireoid clade). This species is found in the inter-Andean Rio Cauca Valley in Colombia. Phylogenetic analyses of nine plastid and nuclear DNA sequences from 44 accessions representing all known Luetzelburgia species show that L. jacana is sister to the rest of the genus and has a mean estimated stem age of ca. 4 Ma, much older than other Luetzelburgia species. Luetzelburgia jacana is distinguished by a combination of mostly 7-9-foliolate, glabrous leaves with leaflets obtuse to shortly acute at the apex, flowers up to 9.6 mm long, and samaras bearing two small lateral wings on the seed chamber. Luetzelburgia jacana, along with two other earliestbranching species in the genus, L. guaissara and L. trialata, are geographical outliers in the genus, with L. jacana having the northernmost distribution and L. guaissara and L. trialata having the southernmost distributions. These three earliest-branching species are also ecological outliers within Luetzelburgia by occurring in wetter and less seasonal settings than other species. The discovery of L. jacana resolves these three earliest-branching species in Luetzelburgia as ecologically transitional between most species of the vataireoid clade that inhabit wet forests and most species of Luetzelburgia that inhabit highly seasonal dry forests and woodlands. [ABSTRACT FROM AUTHOR]

Abstract: The Cerrado Domain of central Brazil houses the largest extent of savanna in the Neotropics, but despite its simple characterization as a giant savanna, it contains considerable vegetation heterogeneity that is poorly understood. We aimed to determine how vegetation types in the Cerrado diverge in their tree species composition and what role ecological factors play in driving compositional patterns. We used a dataset of 1,165 tree species inventories spread across the Cerrado Domain, which come from six vegetation types that have a substantial arboreal component: woody savannas, dystrophic cerradão, mesotrophic cerradão, seasonally dry tropical forests, semideciduous forests and evergreen forests. We found three extremes in terms of tree species composition, with clear underlying ecological drivers, which leads us to propose a ternary model, the Cerrado Vegetation Triangle, to characterize woody vegetation in the Cerrado. At one extreme, we found that semideciduous and evergreen forests are indistinguishable floristically and are found in areas with high water availability. At another extreme lie seasonally dry tropical forests which are found on more fertile soils. At the third extreme, we found that all types of savanna, and dystrophic cerradão, are highly similar in tree species composition and are commonly found in areas of poor soils and high flammability. Mesotrophic cerradão is transitional in tree species composition between savannas and seasonally dry tropical forest. The lack of variation in tree species composition attributed to climatic variables indicates that within homogeneous macroclimatic zones, many types of forest and savanna co‐exist due to complex mosaics of local substrate heterogeneity and fire history. Synthesis. Our findings highlight the complexity of forest–savanna transitions in the Cerrado Domain, with relevance for understanding the future of Cerrado vegetation under environmental change. If nitrogen deposition is extensive, some savannas may be more likely to transition to mesotrophic cerradão or even seasonally dry tropical forest, whereas if water availability increases these same savannas may transition to semideciduous or evergreen forest. Our “Cerrado Vegetation Triangle” model offers a simple conceptual tool to frame discussions of conservation and management. [ABSTRACT FROM AUTHOR]

Abstract Coursetia caribaea is geographically and morphologically the most variable species in the genus Coursetia and in the tribe Robinieae (Leguminosae, Papilionoideae). Because of potentially undetected species, we assessed the phylogenetic relationships among the eight taxonomic varieties of C. caribaea. Sampling included nuclear ribosomal internal transcribed spacer sequences from 489 Robinieae accessions representing all varieties of C. caribaea and 38 of the 40 species of Coursetia, in addition to chloroplast trnD-trnT sequences from 186 accessions. Separate and combined phylogenetic analyses resolved a clade of conspecific accessions of the Bolivian C. caribaea var. astragalina as sister to the central Andean Coursetia grandiflora clade. Also distantly related to Coursetia caribaea var. caribaea accessions were those of the coastal Oaxacan C. caribaea var. pacifica, which formed the sister clade to accessions of the central Andean C. caribaea var. ochroleuca. The estimated mean ages of the stem clades for these three lineages, 11, 7.7, and 7.7 Ma, respectively, contrasted to the estimated mean ages of the corresponding crown clades of 0, 0, and 1.5 Ma. The contrasting stem and crown ages suggest that these taxa, appropriately ranked as species, Coursetia astragalina, Coursetia diversifolia, and Coursetia ochroleuca, each have persisted over evolutionary time frames as distinct geographically localized populations in seasonally dry tropical forests and woodlands. [ABSTRACT FROM AUTHOR]

Summary: The need for species identification and taxonomic discovery has led to the development of innovative technologies for large‐scale plant identification. DNA barcoding has been useful, but fails to distinguish among many species in species‐rich plant genera, particularly in tropical regions. Here, we show that chemical fingerprinting, or ‘chemocoding’, has great potential for plant identification in challenging tropical biomes. Using untargeted metabolomics in combination with multivariate analysis, we constructed species‐level fingerprints, which we define as chemocoding. We evaluated the utility of chemocoding with species that were defined morphologically and subject to next‐generation DNA sequencing in the diverse and recently radiated neotropical genus Inga (Leguminosae), both at single study sites and across broad geographic scales. Our results show that chemocoding is a robust method for distinguishing morphologically similar species at a single site and for identifying widespread species across continental‐scale ranges. Given that species are the fundamental unit of analysis for conservation and biodiversity research, the development of accurate identification methods is essential. We suggest that chemocoding will be a valuable additional source of data for a quick identification of plants, especially for groups where other methods fall short. [ABSTRACT FROM AUTHOR]

We investigate whether the Amotape-Huancabamba zone in the Andes acts as a barrier or corridor for plant species migration. We test this hypothesis based on data on trees, shrubs, and herbs collected in dry inter-Andean valleys (DIAVs) of Ecuador. We found that 72% of the species cross the Amotape-Huancabamba zone in a north-south direction and 13% of the species cross the Andes in an east-west direction. Southern DIAVs concentrate the highest numbers of endemic species. At the regional level we found that 43% of the species are exclusively Andean, while the remaining 57% are found in the Pacific lowlands, the Caribbean, and Mesoamerica. These results showing many species crossing the Amotape-Huancabamba zone in a north-south direction and also frequently found in neighboring lowland and highland ecosystems suggest that the Amotape-Huancabamba zone acts as a corridor for species migration of dry inter-Andean flora. [ABSTRACT FROM AUTHOR]