Genetic and reproductive evidence for two species of ornate wobbegong shark Orectolobus spp. on the Australian east coast

This study reports on evidence for reproductive isolation among Orectolobus ornatus and Orectolobus halei, two previously cryptic and recently redescribed species of wobbegong shark (Orectolobiformes: Orectolobidae) from the east coast of Australia. The evidence is based on disparity in size at sexual maturity, diagnostic nuclear and mitochondrial DNA variants, and marked phylogenetic divergence. Plots of total length (L_T) and maturity for the two species were non‐overlapping and illustrative of statistically significant size dimorphism. Genetic analyses and phylogenetic reconstruction did not provide indication of hybridization between O. ornatus and O. halei. In fact, sequence divergence between them was higher than in comparisons with another congeneric and largely co‐distributed wobbegong species (Orectolobus maculatus). The assumption of a molecular clock revealed that the two species have evolved in isolation for c. 3·9 million years. These results challenge a paradigm often mentioned in the biodiversity literature that most cryptic species are the product of recent speciation events and will contribute to the development of effective management strategies for wobbegong sharks.     

Northern Goshawk Habitat: an Intersection of Science,Management, and Conservation

Abstract: We responded to the claim by Greenwald et al. (2005) that the management recommendations for the northern goshawk in the Southwestern United States (MRNG; Reynolds et al. 1992), a food web-based conservation plan that incorporated both northern goshawk (Accipiter gentilis) and multiple prey habitats, may be inadequate to protect goshawks. Greenwald et al. (2005) based this claim on their review of 12 telemetry studies of goshawk habitat selection and 5 nontelemetry studies of the effects of vegetation structure at the home range scale on goshawk nest occupancy and reproduction that appeared after the 1992 publication of the MRNG. Greenwald et al. (2005) summarized their review as showing that 1) goshawks were habitat specialists limited to forests with mature and old-growth structures including large trees, high canopy cover, multiple canopy layering, and abundant woody debris; 2) habitats were not selected on the basis of prey abundance and, therefore, managing for prey habitats diluted goshawk habitats; and 3) selection for openings, edges, and habitat diversity was inconclusive. Our review found that when the studies' respective authors pooled their radiotagged goshawks there were weak to strong selections for old forest structures. However, the studies also documented extensive variation in use of vegetation types and structures by individual goshawks; some avoided openings, edges, young forests, and old forests, whereas others selected for these characteristics. Additionally, by virtue of their wide geographic distribution, the studies showed that the focal populations themselves occurred in a variety of forest types, some with large structural differences. We found no evidence in Greenwald's et al. (2005) review that the MRNG are inadequate to protect goshawks. Rather, the studies reviewed by Greenwald et al. (2005), as well as many studies they missed, supported the MRNG. The suggestion of inadequacy by Greenwald et al. (2005) appeared rooted in misunderstandings of goshawk habitats described in the MRNG, a discounting of the extent of variation in vegetation structural and seral stages used by goshawks, a limited understanding of the extent to which prey limits goshawks, a failure to recognize the dynamic nature of forests, and an incomplete review of the literature. We believe the MRNG are adequate because they maximize the sustainable amount of mature and old forests in goshawk home ranges and specify the kinds and intermixtures of prey habitats within home ranges. Implementation of MRNG should reduce the likelihood that the availability of vegetation structures suited to goshawk nesting and foraging, as well as abundance and availability of prey, will limit goshawk nest occupancy and reproduction.     

Differential Effects of an Intense Wildfire on Survival of Sympatric Snakes

Abstract: We analyzed 16 years of mark-recapture data to investigate whether a wildfire influenced survival of an arboreal ambush-forager (broad-headed snake [Hoplocephalus bungaroides]) and a terrestrial active forager (small-eyed snake Cryptophis nigrescens). We predicted that wildfire would cause direct mortality and reduce subsequent survival of both snake species. Contrary to this prediction, wildfire did not affect abundance of broad-headed snakes, but abundance of small-eyed snakes decreased by 48% after the wildfire. Estimated annual survival of small-eyed snakes was 37% lower after fire (s=0.47, SE=0.07) than before fire (s=0.74, SE=0.05). Prescribed burning may be a suitable tool for creating open habitat mosaics for the endangered broad-headed snake.     

Species concepts and floras: what are species for?

In 1992, in a special paper in the American Journal of Botany, Ernst Mayr attempted to ‘prove’ the biological species concept (BSC) worked as well in plants as it did in animals by analyzing the flora of the Concord region of northern Massachusetts. He concluded that there were minimal difficulties when applying the BSC for the plants of this particular area, and concluded that botanists were misguided in not accepting the BSC. He suggested that what he called ‘typological’ thinking was prevalent in the taxonomic community, and that this was a factor in botanical resistance to the BSC. Typology, as defined by Mayr in his 1992 foray into botany, is to a certain extent a straw‐man and, by the late 20th Century, no longer a way of thinking in widespread use in the taxonomic community in any organismal group. Here, I examine his analysis in the light of current interest in plant diversity. Species can be characterized as hypotheses about the distribution of variation in nature, subject to test with new data of many kinds. Species concepts like the BSC, although of interest philosophically and to researchers looking at mechanisms of speciation, may actually get in the way of achieving a baseline understanding of the diversity of life on Earth. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 17–25.     

Mitochondrial phylogeography and population history of finless porpoises in Sino‐Japanese waters

Phylogeographical patterns of intraspecific variation can provide insights into the population‐level processes responsible for speciation and yield information useful for conservation purposes. In the present study, three hundred and forty‐five base pairs of the mitochondrial DNA control region were sequenced to analyse the genetic diversity, population structure and history, and phylogeography of finless porpoises (Neophocaena phocaenoides) in Chinese and Japanese waters of the North Pacific. Nucleotide and haplotype diversities were 0.44% and 0.79 ± 0.01 for Chinese and Japanese waters, respectively, but varied significantly among populations. Analysis of molecular variance showed a high level of genetic structure between populations (Φ_ST = 0.61, P < 0.001; F_ST = 0.52, P < 0.001). Eleven of 18 haplotypes were restricted to a single population, common haplotypes were found in two to four populations, but no haplotype was found throughout Sino‐Japanese waters, suggesting multiple colonization events followed by limited gene flow. The inferred age of demographic expansion was from the end stage of the last ice age to the Holocene. No obvious phylogeographical pattern was revealed, including between saline and fresh water populations. A low level of genetic diversity for each population and high among‐population differentiation in haplotype frequency were revealed, which suggest a role for random genetic drift, recent demographic bottlenecks, and reduced or limited gene flow in these populations. Some conservation considerations, with special reference to the unique Yangtze population, are discussed. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 193–204.     

Examining the extinction risk of specialized folivores: a comparative study of Colobine monkeys

Species extinctions are nonrandom with some taxa appearing to possess traits that increase their extinction risk. In this study, eight predictors of extinction risk were used as independent variables to predict the IUCN category of a subfamily of specialized folivorous primates, the Colobinae. All data were transformed into phylogenetically independent contrasts and were analyzed using bivariate regressions, multiple regression, and a maximum likelihood approach using Akaike's Information Criterion to assess model performance. Once an outlier was removed from the data set, species that devote a smaller proportion of their diet to mature leaf consumption appear to be at a greater risk of extinction. Also, as female body mass increases, so does extinction risk. In contrast, as maximum latitude and the number of habitat types increase, extinction risk appears to decrease. These findings emphasize the importance of examining detailed dietary variation for predicting extinction risk at a relatively fine taxonomic scale and, consequently, may help improve conservation management.     

Effects of habitat fragmentation, population size and demographic history on genetic diversity: the Cross River gorilla in a comparative context

In small and fragmented populations, genetic diversity may be reduced owing to increased levels of drift and inbreeding. This reduced diversity is often associated with decreased fitness and a higher threat of extinction. However, it is difficult to determine when a population has low diversity except in a comparative context. We assessed genetic variability in the critically endangered Cross River gorilla (Gorilla gorilla diehli), a small and fragmented population, using 11 autosomal microsatellite loci. We show that levels of diversity in the Cross River population are not evenly distributed across the three genetically identified subpopulations, and that one centrally located subpopulation has higher levels of variability than the others. All measures of genetic variability in the Cross River population were comparable to those of the similarly small mountain gorilla (G. beringei beringei) populations (Bwindi and Virunga). However, for some measures both the Cross River and mountain gorilla populations show lower levels of diversity than a sample from a large, continuous western gorilla population (Mondika, G. gorilla gorilla). Finally, we tested for the genetic signature of a bottleneck in each of the four populations. Only Cross River showed strong evidence of a reduction in population size, suggesting that the reduction in size of this population was more recent or abrupt than in the two mountain gorilla populations. These results emphasize the need for maintaining connectivity in fragmented populations and highlight the importance of allowing small populations to expand.     

中药麝香胶囊抑瘤作用的实验研究

目的探讨中药麝香胶囊对小鼠实验性肿瘤的疗效。方法昆明小鼠分别接种艾氏腹水癌、S-180、肝癌细胞株（hepatocellular carcinoma,HCC）三种癌细胞株,接种24h后开始给予中药麝香胶囊,每日1次,共10d。分高、中、低三个剂量给药（4、2、1g／kg以主药麝香药量计）。阳性对照以天仙丸胶囊（1g／kg）一次性灌服。阴性对照组以同体积生理盐水灌服。接种实体瘤动物于第10天处死,称瘤重,计算抑瘤率;接种腹水瘤动物,观察存活时间,计算生命延长率。结果中药麝香胶囊对实体癌有一定的抑瘤作用,但未达到药典规定的抑瘤率30％的要求;对腹水癌也有一定的抑瘤作用,但也未达到药典规定生命延长率50％的要求;统计学分析（P〉0．05）差异没有显著性。结论中药麝香胶囊抑瘤作用不明显,其配方及剂型有待进一步研究与改进。