Cross-taxon congruence in benthic communities: Searching for surrogates in marine sediments

Cross-taxon congruence has been suggested as an efficient tool in conservation planning and biodiversity monitoring. It corresponds to the degree to which patterns in assemblage structure in a set of sites are similar among different taxonomic groups. If different groups ordinate the sampling sites similarly, they are concordant and this information is frequently used as an indicative that one group could be used as a surrogate for the other. Using spatiotemporal benthic data from a biodiverse coastal ecosystem (the Araçá Bay in southeast Brazil), we first assessed if macro- and meiofaunal assemblages inhabiting marine soft-sediments show concordant patterns. Then, we used multi- and univariate analysis to examine the relationship of both groups with the environment. Macro- and meiofaunal assemblages exhibited strong congruent patterns in all periods analyzed. Moreover, both groups responded to similar environmental features and their ordination patterns matched those generated by the environmental data. These results show that the patterns of concordance are probably mediated by similar responses to environmental gradients. Overall, our results suggest the potential for use of the surrogacy approach in conservation planning and monitoring purposes of marine benthic biodiversity, and that macro- and meiofauna can be used as a surrogate for each other.     

A simplified sampling procedure for field estimation of food consumption of Arctic charr Salvelinus alpinus using gillnets

A study carried out with Arctic charr demonstrated that gastric evacuation terminates when fish are caught in gillnets. This allows the sampling procedure for field estimation of food consumption to be simplified.     

A Vegetation, Climate and Environment Reconstruction Based on Palynological Analyses of High Arctic Tundra Peat Cores (5000–6000 years BP) from Svalbard

As a reference for ongoing studies reconstructing past vegetation, climate and environment, pollen spectra in tundra peat profiles from Svalbard, were investigated. The base of tundra peat cores collected from Ny Ålesund, Stuphallet, Blomstrand and Isdammen has been ¹⁴C dated to 350–490 BP, 5710 BP, 4670 BP and 700–900 BP, respectively. The Stuphallet and Blomstrand (Brøggerhalvøya) peat profiles were composed of a peat developed in a nutrient enriched and wet tundra environment of steep birdcliffs. Pollen concentrations were low, Brassicaceae pollen dominated the whole profile. In contrast, the Ny Ålesund and Isdammen profiles contained high pollen concentrations and suggest a nutrient-poor, dry tundra environment. Pollen of the polar willow, Salix polaris, occurred commonly throughout all four peat profiles. In the relatively high resolution (10 years per peat core sample) analysis of the Ny Ålesund core, starting before or at the beginning of the Little Ice Age (LIA, 16th-mid 19th century), dominance of Saxifraga oppositifolia indicates a cold and dry climate, followed by a decline of Saxifraga oppositifolia and gradual increase of Salix polaris after the LIA, which indicates a moist and milder climate.     

Identifying a reliable blubber measurement site to assess body condition in a marine mammal with topographically variable blubber,the Pacific walrus

Pacific walruses may be unable to meet caloric requirements in the changing Arctic ecosystem, which could affect body condition and have population‐level consequences. Body condition has historically been monitored by measuring blubber thickness over the xiphoid process (sternum). This may be an unreliable condition index because blubber at other sites along the body may be preferentially targeted to balance energetic demands. Animals in aquaria provided an opportunity for controlled study of how blubber topography is altered by caloric intake. Morphology, body mass, blubber thickness (21 sites), and caloric intake of five mature, nonpregnant, nonlactating female walruses were measured monthly (12 month minimum). Body condition (mass × standard length^?1) was described by a model that included caloric intake and a seasonal effect, and scaled positively with estimates of total blubber mass. Blubber thicknesses (1.91–10.69 cm) varied topographically and were similar to values reported for free‐ranging female walruses. Body condition was most closely related to blubber thickness measured dorsomedially in the region of the anterior insertion of the pectoral flippers (shoulders); sternum blubber thickness was a relatively poor indicator of condition. This study demonstrates the importance of validating condition metrics before using them to monitor free‐ranging populations.     

Spatial Models of Northern Bobwhite Populations for Conservation Planning

Abstract: Since 1980, northern bobwhite (Colinus virginianus) range-wide populations declined 3.9% annually. Within the West Gulf Coastal Plain Bird Conservation Region in the south-central United States, populations of this quail species have declined 6.8% annually. These declines sparked calls for land use change and prompted implementation of various conservation practices. However, to effectively reverse these declines and restore northern bobwhite to their former population levels, habitat conservation and management efforts must target establishment and maintenance of sustainable populations. To provide guidance for conservation and restoration of habitat capable of supporting sustainable northern bobwhite populations in the West Gulf Coastal Plain, we modeled their spatial distribution using landscape characteristics derived from 1992 National Land Cover Data and bird detections, from 1990 to 1994, along 10-stop Breeding Bird Survey route segments. Four landscape metrics influenced detections of northern bobwhite: detections were greater in areas with more grassland and increased aggregation of agricultural lands, but detections were reduced in areas with increased density of land cover edge and grassland edge. Using these landscape metrics, we projected the abundance and spatial distribution of northern bobwhite populations across the entire West Gulf Coastal Plain. Predicted populations closely approximated abundance estimates from a different cadre of concurrently collected data but model predictions did not accurately reflect bobwhite detections along species-specific call-count routes in Arkansas and Louisiana. Using similar methods, we also projected northern bobwhite population distribution circa 1980 based on Land Use Land Cover data and bird survey data from 1976 to 1984. We compared our 1980 spatial projections with our spatial estimate of 1992 populations to identify areas of population change. Additionally, we used our projection of the spatial distribution and abundance of bobwhite to predict areas of population sustainability. Our projections of population change and sustainability provide guidance for targeting habitat conservation and rehabilitation efforts for restoration of northern bobwhite populations in the West Gulf Coastal Plain.     

Functional diversity and community structure of micro-organisms in three arctic soils as determined by sole-carbon-source-utilization

Functional diversities of micro-organisms in arctic soils at three incubation temperatures were assessed using sole-carbon-source-utilization (SCSU). Soil samples were collected from an area of anthropogenic fertilization (mixed Dorset/Thule/Historic site), an area of animal enrichment (bird rock perches), and unaltered tundra (raised beach; control soil site). The micro-organisms were extracted from the soil samples and inoculated into Gram-negative (GN) Biolog plates incubated at 30°C, 10°C, and 4°C. Calculations of the Shannon index, substrate utilization richness, Shannon evenness, and the Jaccard coefficient of similarity were based upon substrate utilization on the Biolog plates. Principal component analysis distinguished microbial communities in enriched soils from unenriched soils. At 10°C and 4°C, Shannon indices of enriched soil microbial communities (10°C: soils influenced by wild animals=4.28, soils influenced by human activities=4.20; 4°C: soils influenced by wild animals=4.15, soils influenced by human activities=4.03) were significantly higher than unenriched soil microbial communities (10°C: 3.66; 4°C: 3.38). Substrate utilization richness and evenness displayed similar trends. Although Jaccard coefficients showed uniformity across the different soil samples, cluster analysis supported patterns demonstrated by PCA. Lower temperatures (4°C and 10°C) yielded greater resolution between soil microbial communities than 30°C based on Biolog colour development patterns.     

Tolerance of parr of Arctic charr, Salvelinus alpinus, to reduced dissolved oxygen concentrations

One year old pan Item Windermere (north west England) tolerated lower incipient lethal levels of oxygen [18 20 mg 1 ¹: 15 17% air saturation value (ASV)] at lower (5, 10°C) than at higher (15, 20°C) an elimation temperatures (2·2 2·4 mg 1 ¹ 22 25% ASV). Values were not significantly different for two races of charr in the lake and are amongst the lowest recorded for salmenid species.     

Whale Sanctuaries: An Evolving Concept within the International Whaling Commission

This article analyzes the practice of the International Whaling Commission (IWC) up to 2003 in establishing and regulating international whale sanctuaries, in order to ascertain whether an evolution has taken place in the conservation approach involved. An examination will be made of the IWC's decisions, resolutions, and reports of the Annual Meeting, and of recent proposals presented to the IWC. The results will lead to the identification of a corpus of legal documents supporting the conclusion that an evolution from the mere prohibition of commercial catches to a more comprehensive protection through international whale sanctuary has taken place, even if it has been in a slow and reactive manner.­     

Characterizing the role benthos plays in large coastal seas and estuaries: A modular approach

Ecologists studying coastal and estuarine benthic communities have long taken a macroecological view, by relating benthic community patterns to environmental factors across several spatial scales. Although many general ecological patterns have been established, often a significant amount of the spatial and temporal variation in soft-sediment communities within and among systems remains unexplained. Here we propose a framework that may aid in unraveling the complex influence of environmental factors associated with the different components of coastal systems (i.e. the terrestrial and benthic landscapes, and the hydrological seascape) on benthic communities, and use this information to assess the role played by benthos in coastal ecosystems. A primary component of the approach is the recognition of system modules (e.g. marshes, dendritic systems, tidal rivers, enclosed basins, open bays, lagoons). The modules may differentially interact with key forcing functions (e.g. temperature, salinity, currents) that influence system processes and in turn benthic responses and functions. Modules may also constrain benthic characteristics and related processes within certain ecological boundaries and help explain their overall spatio-temporal variation. We present an example of how benthic community characteristics are related to the modular structure of 14 coastal seas and estuaries, and show that benthic functional group composition is significantly related to the modular structure of these systems. We also propose a framework for exploring the role of benthic communities in coastal systems using this modular approach and offer predictions of how benthic communities may vary depending on the modular composition and characteristics of a coastal system.