Pedro Acevedo-Rodríguez

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.

Plant Conservation in the Caribbean Island Biodiversity Hotspot

While the Caribbean is a recognized “biodiversity hotspot”, plant conservation has not received adequate attention; particularly, given the high levels of endemism in many plant groups. Besides establishing protected areas, there needs to be a sustained effort to study the taxonomy, systematics and ecology of the flora. Recent phylogenetic studies have shown high levels of endemism and conservation studies indicate a large propotion of the flora is threatened with extinction. Eight recommendations are given for plant conservation in the region.

Floristic Richness and Affinities in the West Indies

Comparison of the common floristic elements between the West Indies and the surrounding continents shows a mosaic of affinities that are stronger to Central America and South America as a whole than with either one of them separately or with North America. However, since only 28% of the total West Indian seed plant flora is shared with other geographic regions of the world, the referred exercise is of limited value. Numerous tables are provided to show the distribution of genera throughout the archipelago. The application of phylogenetic studies into the service of biogeography is herein regarded as the next necessary step in elucidating the origins and affinities of the West Indian flora.ResumenEl estudio comparativo de los elementos florísticos que existen en común entre las Indias Occidentales y los continentes circundantes muestran un mosaico de afinidades más cercanas a Centro América y Sur América en su totalidad, que con cualquiera de ellos por separado o con Norte América. Sin embargo, este estudio es de valor limitado ya que solo el 28% del total de la flora de plantas con semillas en las Indias Occidentales es compartido con otras regiones del mundo. En este estudio, se muestran numerosas tablas resumiendo los valores de endemismos, la distribución de los géneros dentro y fuera del archipiélago, así como los géneros más especiosos. La utilización de estudios filogenéticos al servicio de la biogeografía en las Indias Occidentales es considerado como el próximo paso esencial para la elucidación del origen y de las afinidades de la flora Antillana.

Seed Plant Genera Endemic to the Caribbean Island Biodiversity Hotspot: A Review and a Molecular Phylogenetic Perspective

The Caribbean Island Biodiversity Hotspot is composed primarily of the Bahamas and Greater and Lesser Antilles. A total of 180 genera (727 spp., ca. 9% of the species endemic to the Antilles) are restricted to this hotspot. Most of these genera are unispecific (51%), a pattern that is also found on other islands of the world. The majority of the endemic genera belong to the “Core Eudicot” clade, and they were published in two time periods (1854–1878 and 1904–1928). There are molecular phylogenies available for 63 of the endemic genera. However, phylogenetic reconstructions of only 21 genera are based on more than one independent DNA region and have well-supported clades and good taxonomic sampling. Six of the endemic genera form part of early-branching groups. We could not infer biogeographical conclusions from the molecular phylogenies of most of the endemic genera (43: 68%). There is an urgent need for (1) additional field studies to learn the conservation status of these genera, (2) effective protection of the habitats where the most endangered genera occur, and (3) additional biological and systematic studies of the least understood genera.

An integrated assessment of the vascular plant species of the Americas

The vascular plants of the Americas Botanical exploration in the Americas has a history that stretches back for half a millennium, with knowledge assembled in diverse regional floras and lists. Ulloa Ulloa et al. present a comprehensive and integrated compilation of all known native New World vascular plant species (see the Perspective by Givnish). This compilation, in a publicly available, searchable database, includes 124,993 species—about one-third of the worldwide total. They further present details of the distribution of species across families and genera, the geographical foci of diversity, and the floristic relationships between regions. The rate of plant species discovery in the Americas averages almost 750 annually, so this valuable resource will continue to grow. Science, this issue p. 1614; see also p. 1535 A database of all known New World vascular plants holds almost 125,000 species, with the highest concentration in Ecuador. The cataloging of the vascular plants of the Americas has a centuries-long history, but it is only in recent decades that an overview of the entire flora has become possible. We present an integrated assessment of all known native species of vascular plants in the Americas. Twelve regional and national checklists, prepared over the past 25 years and including two large ongoing flora projects, were merged into a single list. Our publicly searchable checklist includes 124,993 species, 6227 genera, and 355 families, which correspond to 33% of the 383,671 vascular plant species known worldwide. In the past 25 years, the rate at which new species descriptions are added has averaged 744 annually for the Americas, and we can expect the total to reach about 150,000.

Addressing target two of the Global Strategy for Plant Conservation by rapidly identifying plants at risk

Target two of the 2002 Global Strategy for Plant Conservation (GSPC), “A preliminary assessment of the conservation status of all known plant species, at national, regional, and international levels” was not accomplished by its original 2010 target date and has therefore been included as a revised 2020 target, “An assessment of the conservation status of all known plant species, as far as possible, to guide conservation action.” The most widely used system to estimate risk of extinction, the International Union for the Conservation of Nature Red List, provides conservation assessments for fewer than 15,000 plant species. Progress achieving Target two has been hampered by the large number of plant species and the difficulty assembling the data needed for Red List assessments. Two streamlined methods for identifying those plant species considered At Risk under the GSPC Target two are compared and contrasted. Both methods use readily available locality data from herbarium specimens to efficiently identify At Risk species and approximate the list of species that would be identified as threatened by Red List analyses. A comprehensive analysis of the native plant species of Puerto Rico using both streamlined methods identifies 570 of the 2,025 species at some risk of extinction. More efficient systems for assessing threat allow a more timely response to Target two, allow conservation efforts to be directed to the species that need attention, and the list of threatened plants can be used to identify priority areas for plant conservation.

Distributional patterns in Brazilian Serjania (Sapindaceae)

The present paper analyzes the distribution of Serjania in Brazil, by comparing and contrasting the species occuring in three major phytogeographic regions: the Atlantic coast, the planalto, and the Amazon basin. The Atlantic coast region has the highest percent (70%) of species endemic to the area, and shares many species with the planalto region. The planalto region shares most of its species with the Atlantic coast and the neighboring countries, but still has a 33% of endemic species to the area. The Amazon basin has only a 4% of species endemic to the area, with most of the reminder species widely distributed through-out the area.

Naturalization and invasion of alien plants in Puerto Rico and the Virgin Islands

Abstract A fundamental goal in invasion ecology is to identify and understand the factors explaining why some alien species become invasive when others fail. In this study we gathered data on taxonomy, invasive status, invasion history, geographic distribution, and biological and ecological traits of 1,032 alien plant species occurring on different habitats in Puerto Rico and the Virgin Islands. These data were used to evaluate the relative importance of habitat and species attributes in influencing the likelihood of alien plants to become naturalized and subsequently invasive on these islands. Our results showed that alien species were more likely to become naturalized if they grow in semi-natural habitats, have large native distribution ranges, long residence time, were introduced for horticulture and have mixed breeding systems. On the other hand, naturalized species were more likely to become invasive if they were introduced for horticulture, behave as weeds, have tolerance to different climatic life-zones, thrive in ruderal habitats, have mixed breeding systems with hermaphroditic flowers, reproduce vegetatively and produce small seeds. Whereas some of these parameters were important for both transitions, others were important for either naturalization or invasion. Overall, our results emphasize the importance of studying different stages of the invasion process in order to understand the mechanisms explaining successful invasions rather than baseline approaches of simply comparing invasive with natives or noninvasive alien species. Understanding the process by which alien species become naturalized or invasive could provide a more objective and accurate approach for managing and predicting biological invasions.

Toward Target 2 of the Global Strategy for Plant Conservation: An Expert Analysis of the Puerto Rican Flora to Validate New Streamlined Methods for Assessing Conservation Status1

Abstract Target 2 of the 2020 Global Strategy for Plant Conservation (GSPC) calls for a comprehensive list of the worlds threatened plant species. The lack of such a list is one of the greatest impediments to protecting the full complement of the worlds plant species, and work to achieve this has been slow. An efficient system for identifying those species that are at risk of extinction could help to achieve this goal in a timeframe sensitive to todays conservation needs. Two systems that efficiently use available data to assess conservation status were tested against a provisional International Union for Conservation of Nature and Natural Resources (IUCN) Red List analysis to evaluate the native seed plant species of Puerto Rico. It was demonstrated that both systems efficiently identify species at risk, which is a step toward both the GSPC Target 2 and a more comprehensive IUCN Red List for plants. Both systems were effective at identifying plant species at risk, with the New York analysis identifying 98% and the Smithsonian analysis 85% of the plant species considered Threatened in the IUCN Red List. Both analyses to some extent overestimated those plants at risk, but the species identified are all range restricted and, thus, of some conservation interest.

Abundance, distribution and conservation significance of regionally endemic plant species on Anegada, British Virgin Islands

The conservation significance of the Caribbean island of Anegada in the British Virgin Islands is highlighted in this study of the distribution of plant species in two major habitats, sand dunes and limestone pavement. In 104 plots along 27 transects located around the western salt ponds of the Anegada Ramsar site, 133 plant species were recorded, including five regional endemics. The limestone pavement supported large populations of Acacia anegadensis, endemic to Anegada, and Cordia rupicola, known only from Anegada and Puerto Rico (although the Puerto Rican population is thought to be extirpated). The sand dunes supported a large population of Metastelma anegadense, also endemic to Anegada. Two other regional endemics were recorded within the limestone cays, Leptocereus quadricostatus, previously known from only one locality in Puerto Rico and Malpighia woodburyana, restricted to a few small populations on islands on the Puerto Rican Bank. For both of these species Anegada supports the largest known individual population. © 2004 FFI.