High proportion of cactus species threatened with extinction (original) (raw)
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Global change impacts on cacti (Cactaceae): current threats, challenges and conservation solutions
Annals of Botany
BackgroundThe plant family Cactaceae provides some of the most striking examples of adaptive evolution, expressing undeniably the most spectacular New World radiation of succulent plants distributed across arid and semi-arid regions of the Americas. Cacti are widely regarded for their cultural, economic and ecological value, yet they are also recognized as one of the most threatened and endangered taxonomic groups on the planet.ScopeThis paper reviews current threats to species of cacti that have distributions in arid to semi-arid subtropical regions. Our review focuses primarily on four global change forces: (1) increases in atmospheric CO2 concentrations; (2) increases in mean annual temperatures and heat waves; (3) increases in the duration, frequency and intensity of droughts; and (4) and increases in competition and wildfire frequency from invasion by non-native species. We provide a broad range of potential priorities and solutions for stemming the extinction risk of cacti spe...
Diversity and conservation in the cactus family
Desert Plants, 2010
Cacti are conspicuous elements of the Western hemisphere. They have long attracted attention due to their peculiar biology, and have maintained close relationships with local settlers. Cacti are used as food, fodder, medicinal and ornamental plants, and as a source of wood. The greatest diversity of this family is recorded in Mexico, with 586 species, followed by Brazil, Argentina, Bolivia and Peru. These countries are also the richest in endemic species. The underlying factors affecting diversity patterns are varied and include temperature, rainfall and geological history. Cacti are threatened by loss and degradation of habitat, and illegal collection. Though it is commonly stated that many species are endangered, most have not yet been evaluated. Due to the growing impact of human activities on biodiversity it is necessary to increase conservation actions to preserve this interesting group of plants, especially in South American countries where knowledge and conservation of cacti are still incipient.
Biodiversity and Biogeography of Cacti
The Cactaceae with c. 1,435 species are the most important plant family of the arid regions of the Americas. Recent revisions and molecular studies resulted in an improved knowledge of the phylogeny and taxonomy of this group. Due to their high value as ornamental plants, countless publications with data on ecological preferences and geographic occurrence of the species are available. In this volume, the distribution areas of all cactus species are mapped. On this basis, we identified and characterized seven geographical centers of cactus diversity. Overall diversity patterns of the family, as well as, diversity patterns of all taxonomic subgroups, growth forms, and pollination syndromes are presented and mapped on the phylogeny of the Cactaceae. More than 50% of the species have extremely small distribution ranges, resulting in potential threat and insufficient coverage by existing protected areas. This volume presents the most comprehensive biogeographical analysis of one of the larger plant families, illustrated by 333 colored maps and c. 60 color figures on c. 200 pages.
Haseltonia, 2022
Abstract: The Chihuahuan Desert Region (CDR) is the largest desert area in North America, and the southeastern portions contain the richest areas in Cactaceae in the continent. This research was advocated to understand the diversity of cacti in northern Zacatecas and southern Coahuila, as well as to explore species rarity, environmental relations and conservation alternatives. A geographical square measuring a quarter degree was intensively surveyed through 50, 3-km long transects, distributed in 25, 6-minute sub-squares. The geographical square was selected because of its altitudinal and environmental heterogeneity. Cacti were identified and local rareness observed, 764 specimens were deposited at the National Herbarium of Mexico (MEXU). Specimen and locality information were captured in the Database for Cacti of Central and North America. A general evaluation of the cactus diversity (species richness), levels of endemism and rarity were performed. A total of 45 species were found, just below El Huizache, Tolimán and Mier y Noriega, with 7 new records for Zacatecas, 2 for Coahuila and 3 for both Mexican states. We found 26 endemic species from the CDR, five endemic to the Main and Meridional subregions and 21 endemic to the Main subregion, sensu Hernández. Two species are endemic to the state of Zacatecas and three species are endemic to both states. A new index for rarity (Average rarity, Ar) is presented, obtained as the mean of five variables: level of endemism, species relative frequencies, local rareness, and climatic and edaphic (soil) specialization. Rabinowitz rarity (1981) was calculated for all species and transformed into numerical values to compare it with the obtained Ar values. There are 26 rare species following Rabinowitz and 16 rare species following Ar (≥0.5). Ar values resulted smooth and with a higher explanation power (r2). Just five species resulted with a Rabinowitz rarity of 7 (transformed R of 1) and Ar (≥0.82). A general complementarity analysis was used to address conservation in the studied area, which was enhanced with other four complementarity analyses, including our Ar. Nine sub-squares were found relevant for cacti protection. Soil types and a complete climatic analysis from original data were used to search for environmental relations through Principal Component Analyses. The main preferences for climatic variables and anomalies are highlighted. The Ar index is an adequate tool for measuring species rarity and presents it in a balanced and smooth way, not just fixed Rabinowitz categories, allowing the understanding that some species might be rare in different ways in different areas and environmental conditions, something that seems to occur in cacti. Further research is encouraged on Ar for comparisons and even mapping, as well as for Natural Protected Areas (NPA) design.
Winners and losers in the predicted impact of climate change on cacti species in Baja California
Plant Ecology, 2020
The Cactaceae is considered one of the most threatened taxa in the world. However, the extent to which climate change could compromise the conservation status of this group has rarely been investigated. The present study advances this issue under three specific aims: (1) to assess the impact of climate change on the distribution of endemic cacti species in the Baja California Peninsula (n = 40), (2) to study how the impact of climate change is distributed in this group according to the species' conservation status, and (3) to analyze how these impacts are organized from a biogeographical and functional perspective. We addressed these objectives under three socioeconomic emission pathways (RCP 2.6, 4.5, and 8.5), and using two extreme migration scenarios: full climate change tracking and no migration. Altogether, all socioeconomic emission pathways under the two extreme migration scenarios show consistency regarding the identity of the species most vulnerable to climate change, and depict a discrepant future scenario that has, on one hand, species with large potential habitat gains/stability (winners); and on the other, species with large habitat reductions (losers). Our work indicates that winner species have a tropical affinity, globose growth, and includes most of the currently threatened species, whereas loser ones are in arid and Mediterranean systems and are mostly non-threatened. Thus, current and future threat factors do not overlap in the biogeographic and taxonomic space. That reveals a worrisome horizon at supraspecific levels in the study area, since the total number of threatened species in the future might largely increase. Keywords Species traits Á Endangered cacti Á Growth form Á Sonoran Desert Á Mexico Communicated by Hsiao-Hsuan Wang.
Biological Conservation
Mapping biodiversity patterns across taxa and environments is crucial to address the evolutionary and ecological dimensions of species distribution, suggesting areas of particular importance for conservation purposes. Within Cactaceae, spatial diversity patterns are poorly explored, as well as the abiotic factors that may predict these patterns. We gathered geographic and genetic data from 922 cactus species, which are tightly associated with drylands, to evaluate diversity patterns, such as phylogenetic diversity and endemism, paleo-, neo-, and superendemism, and the environmental predictor variables of such patterns in a global analysis. Hotspot areas of cacti diversity are scattered along the Neotropical and Nearctic regions, mainly in the desertic portion of Mesoamerica, Caribbean Island, and the dry diagonal of South America. The geomorphological features of these regions may create a complexity of areas that work as locally buffered zones over time, which triggers local events of diversification and speciation. Desert and dryland/dry forest areas comprise paleo-and superendemism and may act as both museums and cradles of species, displaying great importance for conservation. Past climates, topography, soil features, and solar irradiance seem to be the main predictors of distinct endemism types. The hotspot areas that encompass a major part of the endemism cells are outside or poorly covered by formal protection units. The current legally protected areas are not able to conserve cactus evolutionary history. Given the rapid anthropogenic disturbance, efforts must be reinforced to monitor biodiversity and the environment and to define/plan current and new protected areas.
Biogeography and Biodiversity of Cacti
2015
The Cactaceae with c. 1,435 species are the most important plant family of the arid regions of the Americas. Recent revisions and molecular studies resulted in an improved knowledge of their phylogeny and taxonomy. Due to their high value as ornamental plants, countless publications with data on ecological preferences and geographic occurrence of the species are available. In this volume, the distribution areas of all cactus species are mapped. On this basis, we identified and characterized seven geographical diversity centers. Overall diversity patterns of the family, as well as, diversity patterns of all taxonomic subgroups, growth forms, and pollination syndromes are presented and mapped on the phylogeny of the Cactaceae. More than 50% of the species have extremely small distribution ranges, resulting in potential threat and insufficient coverage by existing protected areas. This volume presents the most comprehensive biogeographical analysis of one of the larger plant families, illustrated by 333 colored maps and 55 color figures on c. 200 pages.
Endangered Cacti in the Chihuahuan Desert: II. Biogeography and Conservation
Conservation Biology, 1996
The distributions of the majority of the endangered cacti in the Chihuahuan Desert Region are concentrated in the southeastern and eastern segments of the area, where the predominance of narrow endemism is a remarkable phytogeographic phenomenon. We used three criteria--species richness, conservation value, and complementarity--to evaluate 37 cactus-rich area units in the Chihuahuan Desert. The evaluation of these three quantitative parameters together allowed us to determine that seven of these areas (Huizache, Tolim~n, Ciudad Victoria, Metztitldn, Cuatro Ci~negas, Jaumave, and Xicht~) should be considered conservation priorities because they hold the most significant assemblage of endangered species, in terms of their numbers and their rarity. Conservation actions in these seven areas would protect 52 (55.9%) of the 93 endangered species studied here, most of which have extremely narrow distributions. Geographically, these critical areas are located in the Queretaroan-Hidalgoan arid zone (in the States of Quer~taro, Hidalgo, and Guanajuato)