A brute‐force approach to vegetation classification

Aim: Introduction of a novel approach to the classification of vegetation data (species by plot matrices). This approach copes with a large amount of noise, groups irregularly shaped in attribute space and species turnover within groups. Method: The proposed algorithm (Isopam) is based on the classification of ordination scores from isometric feature mapping. Ordination and classification are repeated in a search for either high overall fidelity of species to groups of sites, or high quantity and quality of indicator species for groups of sites. The classification is performed either as a hierarchical, divisive method or as non‐hierarchical partitioning. In divisive clustering, resulting groups are subdivided until a stopping criterion is met. Isopam was tested on 20 real‐world data sets. The resulting classifications were compared with solutions from eight widely used clustering algorithms. Results: When looking at the significance of species fidelities to groups of sites, and at quantity and quality of indicator species, Isopam often achieved high ranks as compared with other algorithms.     

Beech forest communities in the Nordic countries – a multivariate analysis

In this study we present the first comprehensive multivariate analysis of beech (Fagus sylvatica) forest communities in the Nordic countries. The history of beech and beech forests in Scandinavia are described. In the north, the species is climatically restrained and, at present, restricted to Denmark and the southern parts of Sweden and Norway.More than 2000 sample plots were compiled, partly from literature, partly from new and unpublished data. The material included more than 20 studies of beech forests, often recorded by different non-standardised sampling designs. Therefore, prior to data analysis, a large number of plots had to be excluded to reduce the heterogeneity of the data. Only such sample plots were considered that showed a predominance of Fagus sylvatica in the canopy, that had a size within the interval of 16–100 m2, and that could be located by geographical coordinates. All species abundance values were transformed into simple species presences, and data from different vegetation layers were merged into one.A TWINSPAN cluster analysis resulted in 15 types. Three main communities with several sub-communities and varieties can be distinguished: (1) the Fagus sylvatica-Fraxinus excelsior-Stachys sylvatica community on the most basic and fertile soils, (2) the Fagus sylvatica-Corylus avellana-Galium odoratum community on moderately fertile and acid soils, and (3) the Fagus sylvatica-Sorbus aucuparia-Deschampsia flexuosa community on very acid and oligotrophic soils. Synonyms in the recent literature on Nordic beech forests to these communities are given. An ordination with the program DECORANA confirmed the primary significance of soil acidity and nutrient status for community differentiation.p>     

DNA approach to solve clustering problem based on a mutual order

Clustering is regarded as a consortium of concepts and algorithms that are aimed at revealing a structure in highly dimensional data and arriving at a collection of meaningful relationships in data and information granules. The objective of this paper is to propose a DNA computing to support the development of clustering techniques. This approach is of particular interest when dealing with huge data sets, unknown number of clusters and encountering a heterogeneous character of available data. We present a detailed algorithm and show how the essential components of the clustering technique are realized through the corresponding mechanisms of DNA computing. Numerical examples offer a detailed insight into the performance of the DNA-based clustering.     

氨基酸数量化分类的研究初探

本文以20种α──氨基酸元素组成和主要物理、化学性状指标作为分类的依据,采用系统聚类分析方法,提出一种新的氨基酸分类方法．研究表明,取聚类阈值d＝0.50,可以将20种α──氨基酸分成五类．     

Habitat preferences of Hericium erinaceus in Slovakia

Distribution patterns, ecology and habitats of Hericium erinaceus in Slovakia are presented, together with an indication of its population size and dynamics as driven by the type of substratum the fungus feeds on. Basidiomata have been recorded both on living and dead trees, predominantly on oaks (Quercus spp.) but also on European beech (Fagus sylvatica), and at altitudes ranging from 103 to 753 m, which in Slovakia corresponds to warm hilly and upland beech-oak forests. Standing trunks were a more common substratum than fallen trunks. Although the fungus tends to occur in old-growth forests, nearly half of the observations were from managed forests. Given the observed distribution, we conclude that H. erinaceus is not a strict indicator of intact old-growth forests in Slovakia.     

Recommendations for Assessing the Effectiveness of Surrogate Species Approaches

Surrogate species approaches, including flagship, focal, keystone, indicator, and umbrella, are considered an effective means of conservation planning. For conservation biologists to apply surrogates with confidence, they must have some idea of the effectiveness of surrogates for the circumstances in which they will be applied. We reviewed tests of the effectiveness of surrogate species planning to see if research supports the development of generalized rules for (1) determining when and where surrogate species are an effective conservation tool and (2) how surrogate species should be selected such that the resulting conservation plan will effectively protect biodiversity or achieve other conservation goals. The context and methods of published studies were so diverse that we could not draw general conclusions about the spatial or temporal scales, or ecosystems or taxonomic groups for which surrogate species approaches will succeed. The science of surrogate species can progress by (1) establishing methods to compare diverse measures of effectiveness; (2) taking advantage of data-rich regions to examine the potential effectiveness of surrogate approaches; (3) incorporating spatial scale as an explanatory variable; (4) evaluating surrogate species approaches at broader temporal scales; (5) seeking patterns that will lead to hypothesis driven research; and (6) monitoring surrogate species and their target species.     

Sensitivity of Cerambycid Biodiversity Indicators to Definition of High Diversity

The cutoff used to determine sites of high biological diversity has the potential to influence which species are identified as relevant biological indicators. I␣used data on longhorned beetles and the IndVal program to conduct a sensitivity analysis by varying the definition of high diversity sites from the upper 50% of sites to the upper 5% of sites. The analysis was carried out at all levels of a site typology based on the tree species present at the forested sites. Three species emerged as strong indicators of high diversity sites. Although the indicator values for these species were almost always statistically significant within the upper level of the site typology (all forested sites) the definition of high diversity had a large impact on these values. All three species showed an increase in their indicator values with higher cutoffs for high diversity sites suggesting a relatively nested set of species.     

Temperature thresholds of opportunistic annelids used as benthic indicators of aquaculture impact in Newfoundland (Canada)

In Newfoundland, Canada, aquaculture sites set up over deep, hard bottom substrates dictate the use of visual indicators to monitor aquaculture footprints on the seafloor. Opportunistic annelids (referred to as opportunistic polychaete complexes, or OPC) are among these indicators. The effect of temperature on the distribution and survival of Ophryotrocha cyclops, the species constituting OPC in Newfoundland aquaculture sites is not known. To address this knowledge gap, this study assesses O. cyclops survival at different temperatures in the laboratory, and describes relationships between O. cyclops presence and seafloor temperatures measured in the field. Results show that worms died within two days at temperatures > 12 °C in the laboratory, and appear restricted to temperatures below 7.9 °C at aquaculture sites, tending to be more frequent at temperatures below 5 °C. We recommend that seafloor temperature be recorded and considered in the assessment of benthic aquaculture impact based on OPC presence.     

A preliminary study of the Odonata of S’Albufera Natural Park, Mallorca: status, conservation priorities and bio-indicator potential

This study obtained baseline information for adult Odonata and assessed their conservation priorities and suitability as biological indicators in S’Albufera Natural Park in Mallorca, Spain. At this site, human activities in and around the wetland have raised concerns about their impact on the ecosystem. Investigations on adult diversity produced records of 14 species (four Zygoptera and 10 Anisoptera) and included the first record of Erythromma viridulum for the park. Detrended Correspondence Analysis (DCA) ordination categorised study sites according to their geographical locations in the park and showed clustering of the sites around particular species based on these locations. This pattern might reflect the differences in brackishness in water supplied by different water sources. Canonical Correspondence Analysis (CCA) indicated that some environmental factors were related to particular species. Water flow, vegetation, and depth and size of a water body could discriminate stenotopic species from eurytopic species. Only a few species appeared to be tolerant to the sites with high salinity and low oxygen concentration. The ordination results can be useful for establishing conservation priorities with information of species diversity, abundance, distribution and flight period. Although, with the current limited basic information, the use of Odonata species as biological indicators seems to be difficult, some clear relationships between environmental factors and particular species indicate the great potential of using adult Odonata as biological indicators in the park.     

植原体的最新分类研究动态

简要介绍了植原体分类研究历史与现状,综述了最新的植原体分类方法和植原体候选种的描述规则,指出了我国在植原体分类鉴定方面与当今世界先进水平的差距及今后发展方向.     

植原体的最新分类研究动态

简要介绍了植原体分类研究历史与现状, 综述了最新的植原体分类方法和植原体候选种的描述规则, 指出了我国在植原体分类鉴定方面与当今世界先进水平的差距及今后发展方向。     

Growth rate and its variability in erect Antarctic bryozoans

Climate is altering rapidly in parts of the Arctic and Antarctic but we know little about how marine organisms are responding to, or might respond to such changes. Knowledge of within-taxon variability is the vital context (currently missing) to interpretation of environmental signals. We investigated growth in six species and three genera of erect Antarctic bryozoans, an ideal model taxon to investigate such response. Cellarinella margueritae, C. nodulata, C. rogickae, C. watersi, Melicerita obliqua and Stomhypselosaria watersi, extended 3.4, 5.2, 4.6, 4.1, 4.9 and 4.5 mm year⁻¹ and synthesised 24, 55, 45, 176, 34 and 46 mg CaCO³ year⁻¹, respectively. The maximum ages of these species ranged from 11 to 15 years except M. obliqua, which reached 32 years. This is the first investigation of growth rates of closely related Antarctic invertebrate species and reports the slowest growth rates of bryozoans known from anywhere to date. Our data coupled with that from literature shows that Antarctic bryozoan growth varies <<10¹ between species, 10¹ between genera, 10² between morphologies and is ∼10¹ slower than in tropical or temperate regions. However, within encrusting types the slowest growing species grow at similar rates from poles to tropics. Age was a strong confounding factor across our Antarctic study species but age-standardised data showed a possible decline in annual growth from 1992 to 2003. We identify several factors increasing this environmental signal strength, including (1) the importance of generic (though not necessarily species) identification and (2) use of dry-mass or ash-free dry-mass as the measures of growth.