Validating Landsat-based landscape metrics with fine-grained land cover data

ContextModerate-grained data may not always represent landscape structure in adequate detail which could cause misleading results. Certain metrics have been shown to be predictable with changes in scale; however, no studies have verified such predictions using independent fine-grained data.ObjectivesOur objective was to use independently derived land cover datasets to assess relationships between metrics based on fine- and moderate-grained data for a range of analysis extents. We focus on metrics that previous literature has shown to have predictable relationships across scales.MethodsThe study area was located in eastern Connecticut. We compared a 1 m land cover dataset to a 30 m resampled dataset, derived from the 1 m data, as well as two Landsat-based datasets. We examined 11 metrics which included cover areas and patch metrics. Metrics were analyzed using analysis extents ranging from 100 to 1400 m in radius.ResultsThe resampled data had very strong linear relationships to the 1 m data, from which it was derived, for all metrics regardless of the analysis extent size. Landsat-based data had strong correlations for most cover area metrics but had little or no correlation for patch metrics. Increasing analysis areas improved correlations.ConclusionsRelationships between coarse- and fine-grained data tend to be much weaker when comparing independent land cover datasets. Thus, trends across scales that are found by resampling land cover are likely to be unsuitable for predicting the effects of finer-scale elements in the landscape. Nevertheless, coarser data shows promise in predicting fine-grained for cover area metrics provided the analysis area used is sufficiently large.     

Resolving the Conflicts Between Biodiversity Conservation and Socioeconomic Development in China: Fuzzy Clustering Approach

Resolving the conflicts between biodiversity conservation and socioeconomic development is a global pursuit for the long-run prospects of the human species. Based on Wenchuan County, a typical county in southwestern China, a group of 20 indicators quantifying regional biodiversity and socioeconomic development was established to classify and evaluate the county area spatially. A fuzzy c-means clustering (FCM) algorithm was used as the classification method. Three indices including BD, DL and DR characterizing the value of biodiversity, the level and rate of socioeconomic development of the delineated regions were formulated. The results indicated that Wenchuan County was optimally classified into 4 types of regions (region I to IV). The area percentages of the regions vary widely from 4.3 to 65.7%. The sequences of the regions on biodiversity, socioeconomic development level, and socioeconomic development rate were, respectively, IV > II > III > I, I > III > II > IV and III >I >II >IV. The spatial strategy on coordinating biodiversity conservation and regional development is to develop mainly from the east(I, II, III) and to conserve mainly in the west(IV). Eco-industry, such as eco-tourism and eco-agriculture, need to be emphasized in the process of regional development. The quantitative methods used here may have a wide applicability.     

Ants resort to majority concession to reach democratic consensus in the presence of a persistent minority

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Correction of a bootstrap approach to testing for evolution along lines of least resistance

Testing for an association between the leading vectors of multivariate trait (co)variation within populations (the ‘line of least resistance’) and among populations is an important tool for exploring variational bias in evolution. In a recent study of stickleback fish populations, a bootstrap‐based test was introduced that takes into account estimation error in both vectors and hence improves the previously available bootstrap method. Because this test was implemented incorrectly, however, I here describe the correct test protocol and provide a reanalysis of the original data set. The application of this new test protocol should improve future investigations of evolution along lines of least resistance and other vector comparisons.     

Metazoan parasites of Engraulis ringens as tools for stock discrimination along the Chilean coast

The value of the metazoan parasites of the anchoveta Engraulis ringens as biological tags for stock discrimination is assessed. Three hundred and fifty-nine specimens, obtained from six landing ports in northern and central Chile (Arica, Antofagasta, Caldera, Coquimbo, Valparaiso and Talcahuano) covering a latitudinal gradient of c . 18°, were analysed. Six metazoan parasite species (three ectoparasites and three endoparasites) were obtained. A correspondence analysis suggested that anchoveta from northern and central Chile are comprised of two stocks. Identification of stocks was largely based on qualitative differences (absence in southern localities of the monogenean Pseudanthocotyloides heterocotyle , a parasite proper of engraulids, and the copepod Caligus sp.) and quantitative differences in the prevalence of infection for the remaining species. Inertia and mass value for the correspondence analysis supported the hypothesis of two stocks.     

Morphometric analysis of interspecific and microgeographic variation of crayfish from a Mexican cave

Two undescribed species of Procambarus crayfish (Crustacea, Decapoda) inhabit the subterranean stream running in the recently explored Cueva de Los Camarones, Chiapas, Mexico. Individuals ranging from dark, robust, large-eyed forms with an epigean mien to pale, comparatively slender, microphthalmic ones resembling related troglobites were found, but only the extremes could be distinguished visually. Evolutionary relationships among individuals were investigated morphometrically by means of multivariate analysis'on 14 body dimensions. These analyses revealed a significant discontinuity between the two species, mainly determined by the shape of the rostrum, chelae and telson. The occurrence of a few aberrant phenotypes may indicate the existence of some gene flow between the two species.
Microgeographic variation was demonstrated within the less cavernicolous species. The characters involved were the same as those that discriminate between the two species. These results are compared with allozymic data presented in a parallel paper and the role of genie introgression and environmental induction are discussed.     

Effects of emergence phenology, taxa tolerances and taxonomic resolution on the use of the Chironomid Pupal Exuvial Technique in river biomonitoring

1. We studied chironomid communities of four rivers in south‐eastern Finland, differing in their water quality, during summer 2004 using the Chironomid Pupal Exuvial Technique, CPET. The aims of the study were to (i) test the adequacy of the generic‐level identification in the CPET method, (ii) define the emergence patterns of chironomid taxa classified as intolerant to organic pollution, (iii) assess the tolerance levels of intolerant chironomids and (iv) identify taxa most indicative of good water quality. 2. Procrustean rotation analysis indicated very strong concordance between the ordinations using either species or genus‐level data, suggesting that generic‐level identification of chironomids is adequate for biomonitoring based on CPET. However, when only a few taxa occur in great numbers, it may be advisable to identify these to the species level, especially if these taxa are important indicators of the impact in question. 3. The detection of a particular species may require accurate timing of sampling, whereas a species‐rich genus might be detected throughout a season. Given that the emergence of chironomid species may vary from year‐to‐year and between sampling sites, community differences detected at the species level may be related to between‐site variation in species’ emergence patterns rather than true differences in species composition. 4. Indicator species analysis (IndVal) showed that the distribution and abundance of intolerant chironomid taxa differed strongly among the studied rivers. Some of the intolerant taxa were restricted to unimpacted conditions, whereas others occurred mainly in impacted rivers. Thus, the indicator status of some genera (e.g. Eukiefferiella, Parametriocnemus, Stempellinella and Tvetenia) needs reassessment.     

Coexistence of natural enemies in a multitrophic host–parasitoid system

Abstract.  1. This study explored the temporal and spatial aspects of coexistence over many generations in a multispecies host–parasitoid assemblage.
2. The long-term interaction between the cabbage root fly, Delia radicum (Diptera: Anthomyiidae), and two of its natural enemies, Trybliographa rapae (Hymenoptera: Fitigidae) and Aleochara bilineata (Coleoptera: Staphylinidae), in a cultivated field at Silwood Park over 19 years was explored.
3. Although time series showed that the populations were regulated, the impact of the natural enemies was highly variable. Within-year determinants showed that the spatial response of the specialist parasitoid, T. rapae , was predominantly independent of host density while A. bilineata acted simply as a randomly foraging generalist parasitoid.
4. These findings are compared and contrasted with an earlier investigation of the same system when only the first 9 years of the time series were available. This study demonstrated the potential of long-term field studies for exploring hypotheses on population regulation, persistence, and coexistence.     

Patterns of sexual dimorphism and of variability in the dentition ofOtolemur crassicaudatus

Normative odontometric data are presented on a sample of 66 adult thick-tailed bushbabies Otolemur crassicaudatus(34 male, 32 female). This species is characterized by low levels of sexual dimorphism, with univariate differences centered on the canines and the maxillary third molar. Multivariate canonical analysis isolates a third discriminator, the maxillary second molar. Stepwise discriminant analyses, performed after jackknifing, indicate high percentages of correct classification (males, 79.8–81.8%;females, 81–85.2%). When variability profiles consisting of arrays of CVs are compared, males and females are found to share similar patterns. Data for maxillary teeth offer support for Gingerich’s occlusal complexity model, while morphogenetic clusterings within regressions of variability on tooth size conform to those previously reported in other species. These relationships are lost in the mandibular dentition, suggesting an independence of upper from lower toothsize determination.