Darién E. Prado

Plant diversity patterns in neotropical dry forests and their conservation implications

Seasonally dry tropical forests are distributed across Latin America and the Caribbean and are highly threatened, with less than 10% of their original extent remaining in many countries. Using 835 inventories covering 4660 species of woody plants, we show marked floristic turnover among inventories and regions, which may be higher than in other neotropical biomes, such as savanna. Such high floristic turnover indicates that numerous conservation areas across many countries will be needed to protect the full diversity of tropical dry forests. Our results provide a scientific framework within which national decision-makers can contextualize the floristic significance of their dry forest at a regional and continental scale.

Forgotten forests - issues and prospects in biome mapping using Seasonally Dry Tropical Forests as a case study

BackgroundSouth America is one of the most species diverse continents in the world. Within South America diversity is not distributed evenly at both local and continental scales and this has led to the recognition of various areas with unique species assemblages. Several schemes currently exist which divide the continental-level diversity into large species assemblages referred to as biomes. Here we review five currently available biome maps for South America, including the WWF Ecoregions, the Americas basemap, the Land Cover Map of South America, Morrones Biogeographic regions of Latin America, and the Ecological Systems Map. The comparison is performed through a case study on the Seasonally Dry Tropical Forest (SDTF) biome using herbarium data of habitat specialist species.ResultsCurrent biome maps of South America perform poorly in depicting SDTF distribution. The poor performance of the maps can be attributed to two main factors: (1) poor spatial resolution, and (2) poor biome delimitation. Poor spatial resolution strongly limits the use of some of the maps in GIS applications, especially for areas with heterogeneous landscape such as the Andes. Whilst the Land Cover Map did not suffer from poor spatial resolution, it showed poor delimitation of biomes. The results highlight that delimiting structurally heterogeneous vegetation is difficult based on remote sensed data alone. A new refined working map of South American SDTF biome is proposed, derived using the Biome Distribution Modelling (BDM) approach where georeferenced herbarium data is used in conjunction with bioclimatic data.ConclusionsGeoreferenced specimen data play potentially an important role in biome mapping. Our study shows that herbarium data could be used as a way of ground-truthing biome maps in silico. The results also illustrate that herbarium data can be used to model vegetation maps through predictive modelling. The BDM approach is a promising new method in biome mapping, and could be particularly useful for mapping poorly known, fragmented, or degraded vegetation. We wish to highlight that biome delimitation is not an exact science, and that transparency is needed on how biomes are used as study units in macroevolutionary and ecological research.

Global legume diversity assessment : concepts, key indicators, and strategies

While many plant species are considered threatened under anthropogenic pressure, it remains uncertain how rapidly we are losing plant species diversity. To fill this gap, we propose a Global Legume Diversity Assessment (GLDA) as the first step of a global plant diversity assessment. Here we describe the concept of GLDA and its feasibility by reviewing relevant approaches and data availability. We conclude that Fabaceae is a good proxy for overall angiosperm diversity in many habitats and that much relevant data for GLDA are available. As indicators of states, we propose comparison of species richness with phylogenetic and functional diversity to obtain an integrated picture of diversity. As indicators of trends, species loss rate and extinction risks should be assessed. Specimen records and plot data provide key resources for assessing legume diversity at a global scale, and distribution modeling based on these records provide key methods for assessing states and trends of legume diversity. GLDA has started in Asia, and we call for a truly global legume diversity assessment by wider geographic collabora- tions among various scientists.

Studies on the breeding systems of understorey species of a Chaco woodland in NE Argentina

Summary The breeding systems of seven understorey species in a Chaco woodland in NE Argentina were studied by means of hand pollinations and fluorescence microscopy observations of post-pollination events. Six species showed self-incompatibility (SI), with heteromorphic SI in Erythroxylum microphyllum , and probable homomorphic gametophytic SI (stylar inhibition of selfpollen tubes) in Aechmea distichantha, Bromelia serra, Cleistocactus baumannii, Dyckia ferox and Grabowskia duplicata. Opuntia retrorsa was self-compatible. A notable feature of inter-morph cross-compatibility in E. microphyllum was differential fruiting success using pollen from different stamen whorls of the long-style morpho The high incidence of self-incompatibility in the understorey component of this Chaco woodland is similar to that found in some South American montane forests, and is in contrast to the widespread self-compatibility reported for this stratum in some neotropical forests. It is proposed that these breeding system differences are probably linked to the different taxonomic families represented in the understorey strata of these communities and are not a consequence of adaptations to pollination biology or other ecological factors.

Forest conservation: Remember Gran Chaco—Response

WE AGREE WITH Kuemmerle et al. that the forests in the Gran Chaco region are under massive threat, underprotected, and deserving of greater attention from scientists and conservationists. We could have included the Chaco woodlands in our analyses, and their distinctive flora would have reinforced

Forest conservation: Humans' handprints—Response

WE AGREE WITH Levis et al. that humans have influenced dry forests since their first arrival in the neotropics. This long interaction has had major effects, not least in leading to widespread destruction of this now highly threatened vegetation ([ 1 ][1]). It is also possible, as pointed out by