Filarial infections in California sea lions vary spatially within the Gulf of California, Mexico.

At least two species of filarial worms, Dirofilaria immitis and Acanthocheilonema (Dipetalonema) odendhali, infect otariid pinnipeds, including the California sea lion (Zalophus californianus). To date, evidence of infection in sea lions has come from dead or captive animals, and little is known about filariasis in free-living populations. We sampled 45 California sea lion adults and 197 pups captured at 12 rookeries from different ecological regions within the Gulf of California and detected and quantified D. immitis and A. odendhali microfilariae in blood smears. We investigated differences in prevalence and parasite load (intensity of infection) among ecological regions. Microfilariae were detected in the blood of 35 of the 45 (77.78%) adult females and in 1 of the 197 (0.51%) pups examined. The average burden of A. odendhali per microlitre of blood was nearly twice that of D. immitis. Prevalence and intensity of infection differed significantly among regions, being highest for colonies within the northern and northcentral regions and lowest in the southern region. Dirofilaria immitis and A. odendhali infections displayed a similar spatial pattern of prevalence. Colony density inversely predicted the prevalence of microfilariae. Based on the clinical parameters typically associated with filarial infections in carnivores and physical examinations, none of the sea lions appeared to have evidence of disease. This is a first approximation to investigate the prevalence of microfilaria infections in free-ranging California sea lions and to explore their relevance to population health.

A molecular phylogenetic approach to the systematics of Cylindropuntieae (Opuntioideae, Cactaceae).

Previous taxonomic schemes for the Cylindropuntieae were re-evaluated in the light of a molecular phylogeny derived from a Bayesian, maximum-likelihood and parsimony reconstructions with three plastid regions (atpB-rbcL, psbA-trnH and trnK/matK data sets). The reconstruction revealed that Corynopuntia and Grusonia as currently defined were polyphyletic. Quiabentia, Micropuntia, Pereskiopsis and Cylindropuntia were the only genera recovered as monophyletic. Grusonia s.s. (only including G. bradtiana) is nested in a polytomy with the rest of the species of Corynopuntia. Grusonia s.l. (G. bradtiana plus Corynopuntia) and Corynopuntia as currently defined are polyphyletic because G. pulchella is sister to Pereskiopsis. Some previous taxonomic proposals for Cylindropuntia and Grusonia recognized polyphyletic series and subgenera that do not conform to the strongly supported monophyletic groups here recovered. This study proposes redefining the polyphyletic Grusonia excluding G. pulchella in order to recognize a strongly supported monophyletic genus and the acceptance of a monotypic Micropuntia (G. pulchella) avoiding a new combination into Pereskiopsis. The infrageneric classification for Grusonia is discussed and the recognition of only four monophyletic strongly supported series (Bigelovianae, Imbricatae, Leptocaules and Ramosissimae) for Cylindropuntia is presented.

High proportion of cactus species threatened with extinction.

A high proportion of plant species is predicted to be threatened with extinction in the near future. However, the threat status of only a small number has been evaluated compared with key animal groups, rendering the magnitude and nature of the risks plants face unclear. Here we report the results of a global species assessment for the largest plant taxon evaluated to date under the International Union for Conservation of Nature (IUCN) Red List Categories and Criteria, the iconic Cactaceae (cacti). We show that cacti are among the most threatened taxonomic groups assessed to date, with 31% of the 1,478 evaluated species threatened, demonstrating the high anthropogenic pressures on biodiversity in arid lands. The distribution of threatened species and the predominant threatening processes and drivers are different to those described for other taxa. The most significant threat processes comprise land conversion to agriculture and aquaculture, collection as biological resources, and residential and commercial development. The dominant drivers of extinction risk are the unscrupulous collection of live plants and seeds for horticultural trade and private ornamental collections, smallholder livestock ranching and smallholder annual agriculture. Our findings demonstrate that global species assessments are readily achievable for major groups of plants with relatively moderate resources, and highlight different conservation priorities and actions to those derived from species assessments of key animal groups.

DNA barcodes for Mexican Cactaceae, plants under pressure from wild collecting.

DNA barcodes could be a useful tool for plant conservation. Of particular importance is the ability to identify unknown plant material, such as from customs seizures of illegally collected specimens. Mexican cacti are an example of a threatened group, under pressure because of wild collection for the xeriscaping trade and private collectors. Mexican cacti also provide a taxonomically and geographically coherent group with which to test DNA barcodes. Here, we sample the matK barcode for 528 species of Cactaceae including approximately 75% of Mexican species and test the utility of the matK region for species-level identification. We find that the matK DNA barcode can be used to identify uniquely 77% of species sampled, and 79-87% of species of particular conservation importance. However, this is far below the desired rate of 95% and there are significant issues for PCR amplification because of the variability of primer sites. Additionally, we test the nuclear ITS regions for the cactus subfamily Opuntioideae and for the genus Ariocarpus (subfamily Cactoideae). We observed higher rates of variation for ITS (86% unique for Opuntioideae sampled) but a much lower PCR success, encountering significant intra-individual polymorphism in Ariocarpus precluding the use of this marker in this taxon. We conclude that the matK region should provide useful information as a DNA barcode for Cactaceae if the problems with primers can be addressed, but matK alone is not sufficiently variable to achieve species-level identification. Additional complementary regions should be investigated as ITS is shown to be unsuitable.

Molecular systematics of the Cactaceae.

Bayesian, maximum-likelihood, and maximum-parsimony phylogenies, constructed using nucleotide sequences from the plastid gene region trnK-matK, are employed to investigate relationships within the Cactaceae. These phylogenies sample 666 plants representing 532 of the 1438 species recognized in the family. All four subfamilies, all nine tribes, and 69% of currently recognized genera of Cactaceae are sampled. We found strong support for three of the four currently recognized subfamilies, although relationships between subfamilies were not well defined. Major clades recovered within the largest subfamilies, Opuntioideae and Cactoideae, are reviewed; only three of the nine currently accepted tribes delimited within these subfamilies, the Cacteae, Rhipsalideae, and Opuntieae, are monophyletic, although the Opuntieae were recovered in only the Bayesian and maximum-likelihood analyses, not in the maximum-parsimony analysis, and more data are needed to reveal the status of the Cylindropuntieae, which may yet be monophyletic. Of the 42 genera with more than one exemplar in our study, only 17 were monophyletic; 14 of these genera were from subfamily Cactoideae and three from subfamily Opuntioideae. We present a synopsis of the status of the currently recognized genera. © The Willi Hennig Society 2011.

Endangered Cacti in the Chihuahuan Desert: I. Distribution Patterns.

We mapped the geographical distributions of 93 endangered species of cacti from the Chihuahuan Desert Region. We divided the region into grids of 30 minutes latitude by 30 minutes longitude and calculated species frequencies for each grid. The grids with the highest species richness values are aggregated in areas of moderate elevation, particularly towards the southeastern and to a lesser extent, the eastern margins of the Chihuahuan Desert Region, in northern San Luis Potosi and the southern portions of Coahuila, Nuevo Leén, and Tamaulipas. This vast area constitutes the most important nucleus of cactus species concentration in the continent. Species richness decreases toward the western segment of the Chihuahuan Desert Region and from the Cuatro Ciénegas region to the north and northwest. Another important area is the Queretaroan-Hidalgoan Arid Zone, where several grids containing an important assemblage of endangered species occur. Climatic factors, such as minimum temperatures and mean annual precipitation, explain the current distribution patterns of these plants, and the recent Pleistocene climatic episodes appear to have played a determinant role in the existence of areas of high species concentration and in the proliferation of narrow endemics. Special actions are urgently needed to conserve the endangered Cactaceae of this region. We propose that a carefully selected network of small areas would be an appropriate approach for the conservation of these plants. But species richness cannot be taken as the sole criterion in the determination of protected areas. Additional criteria, such as degree of endemicity, degree of threat to species and areas, habitat diversity, and biogeographic congruence with other plant and animal groups, should be analyzed before these areas are selected. Propagation in botanical gardens using scientific criteria and commercial propagation would be additional methods of conservation. Cactáceas Amenazadas en el Desierto Chihuahuense: I. Patrones de Distribución.

Resumen: Se integraron las distribuciones geográficas de 93 especies de cactáceas amenzadas de la Región del Desierto Chihuahuense. Esta región se subdividió en cuadros de 30 minutos de latitud por 30 minutos de longitud y se calcularon las frecuencias de especies para cada uno de los cuadros. Los cuadros con los mayores valores de riqueza de especies están agregados en áreas de altitud moderada, ubicados particularmente hacia los márgenes sureste, y en menor medida, este de la Región del Desierto Chihuahuense, en el norte de San Luis Potosí, y en el sur de Coahuila, Nuevo León y Tamaulipas. Esta vasta área constituye el núcleo de concentración de especies de cactáceas amenazadas más importante del continente. A partir de esta área, la riqueza de especies decrece hacia el segmento oeste de la Región del Desierto Chihuahuense y de la región de Cuatro Ciénegas hacia el norte y noroeste. Además, en la Zona Arida Queretano-Hidalguense, la cual es considerada como una disyunción del Desierto Chihuahuense, se localizan varios cuadros con un importante contingente de especies amenazadas. Algunos factores climáticos, tales como temperaturas mínimas y precipitación promedio anual, explican los patrones de distribución actuales de estas plantas, y los eventos climáticos del Pleistoceno parecen haber jugado un papel determinante en la existencia de áreas de alta concentración de especies y en la proliferación de endemismos restringidos. Se requieren acciones especiales para protegar a las cactáceas amenazadas de la Región del Desierto Chihuahuense. Se propone que un enfoque apropiado para la conservación de estas plantas podria ser la selección cuidadosa de una red de pequeñas áreas. Sin embargo, la riqueza de especies no es el único criterio en la determinación de áreas protegidas. Existen criterios adicionales tales como la frecuencia de endemismos, el grado de amenaza de áreas y especies en particular, la diviersidad de hábitats y la congruencia biogeográfica con otros grupos de plantas y antimales, los que deberán ser analizados antes de que estas áreas sean seleccionadas. La propagación en jardines botánicos con criterios científicos, así como la propagación comercial, podrían ser métodos adicionales de conservación.