Do non‐native species invasions lead to biotic homogenization at small scales? The similarity and functional diversity of habitats compared for alien and native components of Mediterranean floras

Although a number of recent studies have demonstrated biotic homogenization, these have mainly focused on larger spatial scales. Homogenizing effects are equally important at finer resolutions, e.g. through increasing similarity between habitats, which may result in a simplification of ecosystem structure and function. One major cause of homogenization is the expanding ranges of alien species, although it is not clear whether they are inherently homogenizing at smaller scales. We therefore assessed whether the alien flora is less complex across habitats than the resident native flora of Mediterranean Islands. From a regional data base, we examined floristic lists for between‐habitat taxonomic and functional similarity, and within‐habitat functional diversity, using resampled data sets to control for sample size biases. Aliens and natives showed equivalent complexity in most respects. At the taxonomic level, between‐island and between‐habitat similarities were almost identical, and when ecosystem function was measured by a functional group classification system, this was also true of between‐habitat similarities and within‐habitat diversities. When ecosystem function was measured using Grime's CSR classification, aliens were found to be more functionally homogenous between‐habitats and less functionally diverse within habitats. However, since the CSR profiles of aliens and natives differed, simplification is not inevitable due to ecological segregation of the two floras (aliens tend to be recruited to disturbed habitats rather than displacing natives). One deficiency is a lack of large scale species abundance data. A simple simulation exercise indicated that this is likely to lead to substantial overestimation of true levels of similarity, although would only influence the comparison between aliens and natives if they have different abundance distribution curves. The results indicate that alien floras are not intrinsically more simple than natives, but a higher proportion of competitive strategists among aliens may still cause small‐scale homogenization as these include many strong competitors that are likely to dominate communities.     

Assessment of genetic diversity and relationship among a collection of US sweet sorghum germplasm by SSR markers

Sweet sorghum (Sorghum bicolor L.) is a type of cultivated sorghums and has been recognized widely as potential alternative source of bio-fuel because of its high fermentable sugar content in the stalk. A substantial variation of sugar content and related traits is known to exist in US sweet sorghum. The objectives of the study were to assess the genetic diversity and relationship among the US sweet sorghum cultivars and lines using SSR markers and to examine the genetic variability within sweet sorghum accessions for sugar content. Sixty-eight sweet sorghum and four grain sorghum cultivars and lines were genotyped with 41 SSR markers that generated 132 alleles with an average of 3.22 alleles per locus. Polymorphism information content (PIC) value, a measure of gene diversity, was 0.40 with a range of 0.03–0.87. The genetic similarity co-efficient was estimated based on the segregation of the 132 SSR alleles. Clustering analysis based on the genetic similarity (GS) grouped the 72 sorghum accessions into 10 distinct clusters. Grouping based on clustering analysis was in good agreement with available pedigree and genetic background information. The study has revealed the genetic relationship of cultivars with unknown parentage to those with known parentage. A number of diverse pairs of sweet sorghum accessions were identified which were polymorphic at many SSR loci and significantly different for sugar content as well. Information generated from this study can be used to select parents for hybrid development to maximize the sugar content and total biomass, and development of segregating populations to map genes controlling sugar content in sweet sorghum.     

Deconstructing the long-standing a priori assumption that serial homology generally involves ancestral similarity followed by anatomical divergence

It has long been assumed that serial homologues are ancestrally similar—polysomerism resulting from a “duplication” or “repetition” of forms—and then often diverge—anisomerism, for example, as they become adapted to perform different tasks as is the case with the forelimb and hind limbs of humans. However, such an assumption, with crucial implications for comparative, evolutionary, and developmental biology, and for evolutionary developmental biology, has in general not really been tested by a broad analysis of the available empirical data. Perhaps not surprisingly, more recent anatomical comparisons, as well as molecular knowledge of how, for example, serial appendicular structures are patterned along with different anteroposterior regions of the body axis of bilateral animals, and how “homologous” patterning domains do not necessarily mark “homologous” morphological domains, are putting in question this paradigm. In fact, apart from showing that many so-called “serial homologues” might not be similar at all, recent works have shown that in at least some cases some “serial” structures are indeed more similar to each other in derived taxa than in phylogenetically more ancestral ones, as pointed out by authors such as Owen. In this article, we are taking a step back to question whether such assumptions are actually correct at all, in the first place. In particular, we review other cases of so-called “serial homologues” such as insect wings, arthropod walking appendages, Dipteran thoracic bristles, and the vertebrae, ribs, teeth, myomeres, feathers, and hairs of chordate animals. We show that: (a) there are almost never cases of true ancestral similarity; (b) in evolution, such structures—for example, vertebra—and/or their subparts—for example, “transverse processes”—many times display trends toward less similarity while in many others display trends toward more similarity, that is, one cannot say that there is a clear, overall trend to anisomerism.     

An improved approach to evaluate car sharing options

We develop an improved approach to evaluate car sharing options under uncertain environments with the combination of Fuzzy Analytic Hierarchy Process (F-AHP) and Fuzzy Technique for Order Preference by Similarity to Ideal Solution (F-TOPSIS), which consists of three steps. In the first step, we propose a SCUMN (Specific, Comprehensive, Understandable, Measurable, and Neutral) methodology to identify appropriate indicators and obtain a final list of 24 indicators according to their relevance to car sharing options. In the second step, we determine the weight of each indicator with F-AHP and conduct consistency check of the comparison matrix of selected indicators. In the third step, comparison of different options is performed with selected indicators and F-TOPSIS. A case study is provided to validate the proposed approach. Twenty-four indicators are identified to evaluate five different car sharing options and rank them according to their closeness coefficients in decreasing order. And thirty-one sensitivity analysis experiments are conducted to figure out the influence of indicators on decision making. The experimental results show that the proposed approach is capable of evaluating car sharing options with uncertainty and vagueness. F-AHP is able to determine the weight for each selected indicator and F-TOPSIS demonstrates its advantage in comparing potential options.     

贵州泥堡卡林型金矿区与非金矿区苔藓植物比较研究

首次报道了贵州普安县泥堡村韭菜烂滩的卡林型金矿区和非金矿区的苔藓。记录了泥堡韭菜烂滩卡林型金矿生苔藓3科8属15种,非金矿生苔藓9科15属20种。通过比较我们得到韭菜烂滩卡林型金矿区和泥堡非金矿区苔藓的相似性系数为11.4%。这表明这两个生境下的苔藓组成差异极大。在这个地区有13种苔藓植物(包括异芽丝瓜藓Pohlia leucostoma、卵蒴丝瓜藓P.proligera、长蒴藓Trematodon longicollis等)只生长在卡林型金矿上,这表明有一些苔藓植物适应卡林型金矿这种基质。也许,在泥堡地区某些苔藓植物的分布与卡林型金矿存在一定的关系。     

Land surface phenology as an indicator of biodiversity patterns

With the rapid decline in biodiversity worldwide it is imperative to develop procedures for assessing changes in biodiversity across space. The synoptic view provided by imaging remote sensors constitutes a suitable approach for analyzing biodiversity from local to regional scales. A procedure based on the close relationship between floristic similarity and the similarity in land surface phenology was recently developed and successfully applied to assess diversity patterns using time series imagery acquired by the Moderate Resolution Imaging Spectro-radiometer (MODIS). However, as it depends on high temporal resolution remotely sensed data (e.g., MODIS), the procedure is constrained by the coarse spatial resolution characterizing these high temporal resolution data. Using an optimized technique for image fusion, we combined high temporal resolution data acquired by the MODIS sensor system with moderate spatial resolution data acquired by the Landsat TM/ETM+ sensor systems. Our results show that the MODIS/Landsat data fusion allows the characterization of land surface phenology at higher spatial resolutions, which better corresponded with information acquired within vegetation survey plots established in temperate montane forests located in Wolong Nature Reserve, Sichuan Province, China. As such, the procedure is useful for capturing changes in biodiversity induced by disturbances operating at large spatial scales and constitutes a suitable tool for monitoring and managing biodiversity.     

Atlas versus range maps: robustness of chorological relationships to distribution data types in European mammals

Aim Chorological relationships describe the patterns of distributional overlap among species. In addition to revealing biogeographical structure, the resulting clusters of species with similar geographical distributions can serve as natural units in conservation planning. Here, we assess the extent to which temporal, methodological and taxonomical differences in the source of species’ distribution data can affect the relationships that are found. Location Western Europe. Methods We used two data sets – the Atlas of European mammals and polygon range maps from the IUCN Global Mammal Assessment – both as presence–absence data for UTM 50 km × 50 km squares. We performed pairwise comparisons among 156 species for each data set to build matrices of the similarity in distribution across species, using both Jaccard’s and Baroni‐Urbani & Buser’s indices. We then compared these similarity matrices (chorological relationships), as well as the species richness and occurrence patterns from the two data sets. Results As expected, range maps increased both the mean prevalence per species and mean species richness per grid cell in comparison to atlas data, reflecting the general view that these data types respectively over‐ and underestimate species occurrence. However, species richness and occurrence patterns in atlas and range map data were positively associated and, most importantly, the chorological relationships underlying the two data sets were highly similar. Main conclusions Despite many methodological, temporal and taxonomical differences between atlas data and range maps, the chorological relationships encountered between species were similar for both data sets. Chorological analyses can thus be robust to the data source used and provide a solid basis for analytical biogeographical studies, even over broad spatial scales.