A comparison of statistical approaches to analyzing community convergence between natural and constructed oyster reefs

Evaluating the success of habitat creation or restoration depends primarily on the selection of appropriate goals, relevant metrics and robust analytic approaches. For intertidal oyster reefs, the goal of restoring ecological function often is as important as the production of harvestable oysters, especially since oysters are the habitat. Assessing differences in resident faunal composition between created and natural reefs is one possible metric for evaluating ecological success. Yearly changes in the resident faunal composition on constructed and natural intertidal oyster reefs at one South Carolina restoration site were analyzed with a variety of statistical approaches to determine the most effective method(s) for documenting possible convergence in the similarity of reef assemblages over time. Two datasets were defined by the level of taxonomic identification, all taxa or a subset of common taxa, and the level of taxa reduction; all taxa, taxa > 1% of total abundance, and taxa significantly contributing to variation. Data were analyzed using “classic” multivariate analysis of variance (MANOVA), null model analysis of co-occurrence (ECOSIM), nonparametric analysis of similarity (ANOSIM), and permutation tests for multivariate analysis of similarity (PERMANOVA). Taxa abundance was used to weight MANOVA and ECOSIM analyses, while the Bray-Curtis dissimilarity index was used to weight ANOSIM and PERMANOVA analyses. Initial constraints on the analytic design and data manipulations resulted in only one test where convergence of the constructed and natural reef assemblages was indicated. Prescribed reductions in the suite of taxa considered did not alter appreciably the results. The analytic approaches varied in suitability and effectiveness at discriminating among changes in compositional similarity, even when initial constraints were relaxed. MANOVA results indicated either no difference or a significant difference in resident faunal composition between reefs, but were compromised by the inability to transform the data sufficiently to test for multivariate homogeneity violations even in analyses with reduced taxa numbers. Interpretation of ECOSIM results suggested fewer taxa in common even on natural reefs and were affected by a lack of design alternatives and the possible inflation of Type I error that weighting by abundance may cause. ANOSIM results identified no significant reef treatment effects and also suffered from design constraints and an inability to generate enough permutations to test for significant differences in datasets with relatively small sample sizes. All test results from PERMANOVA analyses except one indicated unambiguously that resident faunal assemblages on constructed reefs generally were not yet similar to natural reefs even after 7 years. Convergence of constructed and natural reef resident assemblages was suggested by PERMANOVA tests only for the dataset with the fewest taxa. The negligible limitations of PERMANOVA, flexible design options, and ability to generate significance tests for small sample sizes make the approach powerful. The ongoing development of effective statistical approaches for testing the significance of taxonomic compositional changes among habitats makes the determination of whether restoration projects are successful less dependent on the choice of analytic technique. More critical, biological questions including whether convergence of taxa abundance and composition is a valid indicator of similar ecological function remain to be answered.     

The use of coarser taxonomic resolution in studies of predation on marine sedimentary fauna

Given the logistical difficulties, cost, and time involved in species-level identifications, several authors have proposed the use of coarser taxonomic resolution (e.g. family, order) in studies of pollution. The use of surrogates instead of species relies on their sufficiency to detect community responses to the pollution gradient without appreciable loss of information. No studies, however, have applied this approach to experimental studies such as community responses to predation disturbance and evaluated the performance of surrogates at the spatial scales typical of experiments. We addressed both problems by analyzing the results of three predation experiments carried out in Bonne Bay, Newfoundland. We pooled species data into coarser taxonomic categories (family to class) and determined whether effects of predation that were evident at the species level were also evident with the use of each coarser surrogate and increasing data transformation. Our results indicate that non-transformed data at the family level represent a reasonable surrogate of species; however, the ability to discriminate between ambient and (predator) manipulated sediments is gradually lost with data transformation and with the pooling of species into coarser taxonomic categories. Successive data transformation indicates that in this system predation plays a strong role on dominant but not necessarily rare species. Moreover, our results suggest that varying reliability of surrogates precludes the identification of a single general level of taxonomic sufficiency to be used in experimental studies. The use of surrogates, therefore, is suggested only after scrutiny and evaluation, and should be limited to preliminary studies where biodiversity has been well described.     

The relationship between water availability and anatomical characters in Carex hirta

The effects of edaphic moisture in anatomical characters were evaluated in two different populations of Carex hirta L. with three watering treatment for 6 months to evaluate stability, and determined taxonomic value. Water availability increased (p < 0.001) leaf thickness from 239 to 289 μm, metaxylem vessel diameter from 17 to 23 μm, air cavity size from 10 to 24% and adaxial epidermal cell height from 18 to 34 μm, and abaxial from 11 to 16 μm, adaxial epidermal cell length from 54 to 105 μm, and abaxial from 35 to 86 μm, and adaxial epidermal cell width from 20 to 33 μm, and abaxial from 15 to 23 μm. Stomatal index and the number of cells in the girder of sclerenchyma did not vary with water availability, hence these traits have taxonomic value. Other characters (the length and amplitude of wall undulations in the epidermal cells, the number of bulliform cells) have a doubtful relation with water availability, because they are variable even in constant homogeneous conditions.     

Snake fauna (Reptilia: Serpentes) from the Early/Middle Miocene of Sandelzhausen and Rothenstein 13 (Germany)

The Early/Middle Miocene (European Land Mammal Zone MN5) localities of Sandelzhausen and Rothenstein 13 in southern Germany have yielded remains of about 13 ophidian taxa: Eoanilius sp. (Aniliidae), Bavarioboa ultima (Boidae), “Coluber” sp., ?Telescopus sp., Natrix sp., cf. Natrix sp., cf. “Neonatrix” sp., unidentified “colubrines” and “natricines” (Colubridae), Naja sp., an unidentified elapid (Elapidae), Vipera sp. (“Oriental viper”), Vipera sp. (“aspis complex”) (Viperidae). Both faunas document a transitional phase from those reported from several late Early and Middle Miocene sites of Central and Western Europe. The climates of Sandelzhausen and Rothenstein 13, as indicated by ophidian fossils, were warm, although not tropical or subtropical.     

Co-occurrence of Pseudocercospora species and rhytismatalean ascomycetes on maple and camellia in Taiwan

A new species of Pseudocercospora on leaves of Acer albopurpurascens, a maple endemic to Taiwan, is described. The fungus sporulated on leaf spots caused by Vladracula annuliformis (Rhytismatales). Pseudocercospora camelliicola and Coccomyces sinensis on leaves of Camellia cultivars are recorded for the first time for Taiwan and described and illustrated in detail. In contrast to the situation on maple, both fungal species on camellia caused conspicuous breakage of the epidermis during sporulation, which is discussed in connection with fungal succession during leaf litter decomposition.     

Taxonomic size structure consistency of the English Channel phytoplankton

Here we report the worldwide first results on long-term variability of marine phytoplankton taxonomic size structure based on traditional taxonomic size spectra (TTSS). The Plymouth Marine Laboratory monitoring database for station L4 was used to build annual TTSS patterns (1992-2005) and estimate their similarity with the help of hierarchical cluster analysis. Almost identical TTSS patterns were observed each year. While the height of the main peaks was slightly variable, their horizontal positions were unchanged. Whereas the above patterns resembled the phytoplankton TTSS established for the subtropical Lake Kinneret, the L4 spectrum size range was much broader and the distance between the main peaks approximately two times greater. The similarity level (Pearson r = 0.872-0.992) in TTSS pairs for station L4 was comparable to the estimates established at several lakes, while being much higher than in the inter-ecosystem (L4 and Kinneret) pairs (r = 0.317-0.578). Thus, the phenomenon of long-term consistency of phytoplankton taxonomic size structure, found previously at freshwater ecosystems, for the first time is confirmed for marine phytoplankton, which speaks in favor of much higher generality of this important structural property of aquatic communities. The TTSS multi-annual consistency can be helpful for long-term monitoring, environment protection and forecasting. The evident and permanent difference in the peak positions between ecosystems opens a way for additional analyses which can be helpful for the development of theoretical models. A set of plausible mechanisms, capable to produce and support the empirically obtained distribution patterns, is discussed.     

The Saurida undosquamis group (Aulopiformes: Synodontidae), with description of a new species from southern Japan

Four lizardfishes of Saurida (family Synodontidae), S. undosquamis, S. umeyoshii sp. nov., S. macrolepis, and S. longimanus, are described. All are recognized here as the Saurida undosquamis group, characterized by having dark dots on the upper margin of the caudal fin, pectoral fin exceeding origin to pelvic fin, anterior rays of dorsal fin neither elongate nor filamentous, predorsal length greater than distance between dorsal-fin and adipose-fin origins, 46–55 pored lateral-line scales, and vomer with 0–8 teeth. Saurida undosquamis, from northern West India and West Pacific, excluding East Asia, differs from others in having lateral-line scales ridged on the caudal peduncle, conspicuously concave posterior margin of the pectoral fin, 51–55 pored lateral-line scales, and 50–53 vertebrae. Saurida umeyoshii sp. nov., from southern Japan and the East China Sea, is defined by three rows of indistinct dark blotches on, above, and below the lateral line, distribution of scale pockets with melanophores on their posterior part extending over the entire abdominal region from the lateral line in specimens over ca. 130 mm SL, lateral-line scales not ridged on caudal peduncle, 49–52 pored lateral-line scales, and 48–50 vertebrae. Saurida macrolepis, from the Indo-West Pacific, is characterized by 46–49 pored lateral-line scales and 45–48 vertebrae. Saurida longimanus, from northern West India, northwest Australia, and southern Indonesia, differs from the others in having a long pectoral fin extending past the origin of the dorsal fin. Some geographic variations are found in S. macrolepis. Saurida grandisquamis is confirmed as a junior synonym of S. undosquamis, based on examination of the type specimens. A key to species in the S. undosquamis group is included.     

Polychaetes as surrogates for marine biodiversity: lower taxonomic resolution and indicator groups

Due to conservation needs, reliable rapid-assessment methods for mapping of biodiversity are needed. One approach is to use surrogates, i.e. quantities that correlate strongly with the number of species, but are easier to obtain. The purpose of this paper is to test two polychaete surrogates, one for higher taxa and one for indicator groups, that will facilitate prediction of species richness in marine soft-bottom communities. Soft sediment is an important habitat which covers most of the ocean bottom. Data on polychaetes from the North Atlantic were used since polychaetes are often numerically dominant in the benthic assemblages, both with regard to the number of species and their abundance. In the polychaete assemblages along the Norwegian coast, richness at the genus, family and order level were significantly, linearly correlated to total species richness (r 0.92). Polychaetes in the order Terebellida were found to be a good indicator of polychaete species richness and to a lesser extent also of whole benthic assemblages. The group Terebellida is potentially well suited as an indicator group, since it contains long-lived, large species that are easy to sort from the sediment and it is well defined taxonomically. Although promising as proxies for species richness in marine biodiversity studies, the use of lower taxonomic resolution and indicator groups requires further investigations in more local areas where there are conservation issues.     

小叶栒子的分类学研究

据有关模式和产地标本的研究，结合野外调查、叶表皮微形态观察结果，对小叶栒子（Cotoneaster microphyllus Wall.ex Lindl.)进行了分类学修订，将分属 ３系（Series Procumbens Klotz; Series Alpigeni和Series Marginati Klotz）的１５个名称归并作小叶栒子的同物异名。     

中国特有属─—东俄芹属的花粉形态及其分类学意义

利用光学显微镜和扫描电镜观察了伞形科东俄芹属（ＴｏｎｇｏｌｏａＨ．Ｗｏｌｆｆ）７个种的花粉形态,结果表明：除宜昌东俄芹Ｔ．ｄｕｎｎｉｉ（Ｂｏｉｓｓｉｅｕ）Ｈ．Ｗｏｌｆｆ和城口东俄芹Ｔ．ｓｉｌａｉｆｏｌｉａ（Ｂｏｉｓｓｉｅｕ）Ｈ．ｗｏｌｆｆ的花粉为矩形类型外,其它几种的为菱形类型,然而并非都是原始的或典型的菱形,而是处于分化过程中的菱形类型,如纤细东俄芹Ｔ．ｇｒａｃｉｌｉｓＨ．Ｗｏｌｆｆ,大东俄芹Ｔ．ｅｌａｔａＨ．Ｗｏｌｆｆ的花粉形态,表现出近菱形、近椭圆形和近矩形的特征,在我们近期的工作中曾涉及滇芎属ＰｈｙｓｏｓｐｅｒｍｏｐｓｉｓＨ．Ｗｏｌｆｆ类似的花粉形态及分化情况,从花粉资料启示,东俄芹属可能与滇芎属近缘。