Abundance, spatial distribution and habitat relationships of echinoderms in the Cabo Verde Archipelago (eastern Atlantic)

2008 ◽  
Vol 59 (6) ◽  
pp. 477 ◽  
Author(s):  
Laura Entrambasaguas ◽  
Ángel Pérez-Ruzafa ◽  
Jose A. García-Charton ◽  
Ben Stobart ◽  
Juan José Bacallado
Keyword(s):  
Spatial Variability ◽  
Habitat Structure ◽  
Sea Urchins ◽  
Spatial Scales ◽  
Benthic Communities ◽  
Fine Scale ◽  
Cabo Verde ◽  
Heterogeneous Habitats ◽  
Species Abundances ◽  
Species Specific

The analysis of spatial variability in distribution and abundance of echinoderms may help in identifying the range of processes that can explain the observed patterns of this important component of benthic communities. The distribution and abundance of the echinoderm assemblage inhabiting the shallow rocky reefs at the Cabo Verde archipelago (where few studies other than descriptive ones have been performed until now) was quantified at three spatial scales (among islands, between locations within islands, and among replicates), at two depth strata, and related to fine-scale variation of habitat structure. Total echinoderm abundance and the abundance of the sea urchins Diadema antillarum and Eucidaris tribuloides, and the holothurian Euapta lappa were heterogeneous at the largest considered scale. Most species and habitat descriptors exhibited spatial variability at finer scales. There were significant relationships between habitat architecture and depth and both assemblage parameters and species abundances. Although the effects of habitat structure were species-specific, the probability of occurrence of Asteroidea, Ophiuroidea and Holothuroidea species was higher in heterogeneous habitats. Meanwhile Echinoidea and Holothuroidea species showed higher correlations to complex habitats. The observed spatial patterns are inferred to reflect behavioural responses to fine-scale microhabitat complexity, as well as broad-scale oceanic variables and recruitment dynamics.

Assessment of the spatial variability of intertidal benthic communities by axial tomodensitometry: importance of fine-scale heterogeneity

2003 ◽  
Vol 287 (2) ◽  
pp. 193-208 ◽  
Author(s):  
Florian Mermillod-Blondin ◽  
Sabrina Marie ◽  
Gaston Desrosiers ◽  
Bernard Long ◽  
Laure de Montety ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Benthic Communities ◽  
Fine Scale ◽  
Scale Heterogeneity

scholarly journals Fine-Scale Mapping of Mega-Epibenthic Communities and Their Patch Characteristics on Two New Zealand Seamounts

2021 ◽  
Vol 8 ◽  
Author(s):  
Savannah L. Goode ◽  
Ashley A. Rowden ◽  
David A. Bowden ◽  
Malcolm R. Clark ◽  
Fabrice Stephenson
Keyword(s):  
Community Structure ◽  
New Zealand ◽  
Environmental Variables ◽  
Community Dynamics ◽  
Spatial Scales ◽  
Benthic Communities ◽  
Environmental Drivers ◽  
Fine Scale ◽  
Patch Characteristics ◽  
Epibenthic Communities

Seamounts are common features of the deep seafloor that are often associated with aggregations of mega-epibenthic fauna, including deep-sea corals and sponges. Globally, many seamounts also host abundant fish stocks, supporting commercial bottom trawl fisheries that impact non-target benthic species through damage and/or removal of these non-target species. However, the effects of bottom trawling on seamount benthic communities, as well as their recovery potential, will vary over the total seamount area because of differences in within seamount habitat and community structure. It is therefore important to understand fine-scale community dynamics, community patch characteristics, and the environmental drivers contributing to these patterns to improve habitat mapping efforts on seamounts and to determine the potential for benthic communities on seamounts to recover from fishing disturbances. Here we analysed the structure and distribution of mega-epibenthic communities on two New Zealand seamounts with different physical environments to determine which environmental variables best correlated with variation in community structure within each seamount. We used the identified environmental variables to predict the distribution of communities beyond the sampled areas, then described the spatial patterns and patch characteristics of the predicted community distributions. We found the environmental variables that best explained variations in community structure differed between the seamounts and at different spatial scales. These differences were reflected in the distribution models: communities on one seamount were predicted to form bands with depth, while on the other seamount communities varied mostly with broadscale aspect and the presence of small pinnacles. The number and size of community patches, inter-patch distances, and patch connectedness were found to differ both within and between seamounts. These types of analyses and results can be used to inform the spatial management of seamount ecosystems.

scholarly journals Diversity and Structure of Parrotfish Assemblages across the Northern Great Barrier Reef

Diversity ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 14 ◽  
Author(s):  
Garrett Johnson ◽  
Brett Taylor ◽  
William Robbins ◽  
Erik Franklin ◽  
Rob Toonen ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Spatial Scales ◽  
Nutritional Ecology ◽  
Assemblage Structure ◽  
Barrier Reef ◽  
Complex Environments ◽  
Related Factors ◽  
Species Abundances ◽  
Recent Developments ◽  
Species Specific

The structure and dynamics of coral reef environments vary across a range of spatial scales, with patterns of associated faunal assemblages often reflecting this variability. However, delineating drivers of biological variability in such complex environments has proved challenging. Here, we investigated the assemblage structure and diversity of parrotfishes—a common and ecologically important group—across 6° of latitude on the Northern Great Barrier Reef (GBR), Australia. Parrotfish abundance and biomass were determined from stereo-video surveys across 82 sites spanning 31 reefs and assessed against geographic, biophysical, and management-related factors in a multivariate framework to determine major drivers and associated scales of assemblage structure. Large cross-shelf variation in parrotfish assemblages pervaded along the entire Northern GBR, with distinct assemblages associated with sheltered and exposed reefs. Species abundances and diversity generally decreased with decreasing latitude. The gradient of explicit predator biomass associated with management zoning had no effect on parrotfish assemblage structure, but was positively correlated with parrotfish diversity. Our results highlight the ubiquitous presence of cross-shelf variation, where the greatest differences in parrotfish community composition existed between sheltered (inner and mid shelf) and exposed (outer shelf) reef systems. Prior attempts to explain linkages between parrotfishes and fine-scale biophysical factors have demonstrated parrotfishes as habitat generalists, but recent developments in nutritional ecology suggest that their cross-shelf variation on the GBR is likely reflective of benthic resource distribution and species-specific feeding modes.

Variability in forest floor at different spatial scales in a natural forest in the Carpathians: effect of windthrows and mesorelief

2008 ◽  
Vol 38 (10) ◽  
pp. 2596-2606 ◽  
Author(s):  
P. Šamonil ◽  
K. Král ◽  
J. Douda ◽  
B. Šebková
Keyword(s):  
Spatial Variability ◽  
Spatial Dependence ◽  
Forest Floor ◽  
Spatial Scales ◽  
Beech Forest ◽  
High Variability ◽  
Organic Horizon ◽  
Fine Scale ◽  
Coarse Scale ◽  
Organic Horizons

Spatial variability of humus properties in a natural fir–beech forest was studied along with the influence of windthrows and mesorelief on this variability. In 1720 windthrows the thickness and form of the organic horizons were studied in three positions — mound, pit, and undisturbed control. On undisturbed sites, substantial variability of thickness and forms of the organic horizons was found on a fine scale (0–10 m). Close spatial dependence of some humus characteristics was found on a coarser scale (20–120 m). The mesorelief was found to be one of the key autocorrelation factors. The level of spatial dependence was not uniform; it differed between the fermented and humification horizons and among their forms. The presence of windthrows increased the variability of humus thickness on both fine (0–10 m) and coarse (level of entire locality, i.e., 11 ha) scales. However, windthrows did not increase the variability of organic horizon forms (OHFs) on a fine scale. High variability of OHFs is probably a property of fully developed mature humus in a natural fir–beech forest. On a coarse scale, the presence of pits increased the frequency of fermented zoogenous and humification residual horizons on the study area.

scholarly journals Repeated surveying over 6 years reveals that fine-scale habitat variables are key to tropical mountain ant assemblage composition and functional diversity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mulalo M. Muluvhahothe ◽  
Grant S. Joseph ◽  
Colleen L. Seymour ◽  
Thinandavha C. Munyai ◽  
Stefan H. Foord
Keyword(s):  
Climate Change ◽  
Species Composition ◽  
High Altitude ◽  
Functional Diversity ◽  
Large Scale ◽  
Climate Models ◽  
Spatial Scales ◽  
Abiotic Factors ◽  
Composition Analysis ◽  
Fine Scale

AbstractHigh-altitude-adapted ectotherms can escape competition from dominant species by tolerating low temperatures at cooler elevations, but climate change is eroding such advantages. Studies evaluating broad-scale impacts of global change for high-altitude organisms often overlook the mitigating role of biotic factors. Yet, at fine spatial-scales, vegetation-associated microclimates provide refuges from climatic extremes. Using one of the largest standardised data sets collected to date, we tested how ant species composition and functional diversity (i.e., the range and value of species traits found within assemblages) respond to large-scale abiotic factors (altitude, aspect), and fine-scale factors (vegetation, soil structure) along an elevational gradient in tropical Africa. Altitude emerged as the principal factor explaining species composition. Analysis of nestedness and turnover components of beta diversity indicated that ant assemblages are specific to each elevation, so species are not filtered out but replaced with new species as elevation increases. Similarity of assemblages over time (assessed using beta decay) did not change significantly at low and mid elevations but declined at the highest elevations. Assemblages also differed between northern and southern mountain aspects, although at highest elevations, composition was restricted to a set of species found on both aspects. Functional diversity was not explained by large scale variables like elevation, but by factors associated with elevation that operate at fine scales (i.e., temperature and habitat structure). Our findings highlight the significance of fine-scale variables in predicting organisms’ responses to changing temperature, offering management possibilities that might dilute climate change impacts, and caution when predicting assemblage responses using climate models, alone.

scholarly journals Imaging spectroscopy links aspen genotype with below-ground processes at landscape scales

2014 ◽  
Vol 369 (1643) ◽  
pp. 20130194 ◽  
Author(s):  
Michael D. Madritch ◽  
Clayton C. Kingdon ◽  
Aditya Singh ◽  
Karen E. Mock ◽  
Richard L. Lindroth ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Populus Tremuloides ◽  
Spatial Scales ◽  
Imaging Spectroscopy ◽  
Spectral Signature ◽  
Spectral Variation ◽  
Fine Scale ◽  
Below Ground ◽  
Landscape Scales ◽  
Spectrometer Data

Fine-scale biodiversity is increasingly recognized as important to ecosystem-level processes. Remote sensing technologies have great potential to estimate both biodiversity and ecosystem function over large spatial scales. Here, we demonstrate the capacity of imaging spectroscopy to discriminate among genotypes of Populus tremuloides (trembling aspen), one of the most genetically diverse and widespread forest species in North America. We combine imaging spectroscopy (AVIRIS) data with genetic, phytochemical, microbial and biogeochemical data to determine how intraspecific plant genetic variation influences below-ground processes at landscape scales. We demonstrate that both canopy chemistry and below-ground processes vary over large spatial scales (continental) according to aspen genotype. Imaging spectrometer data distinguish aspen genotypes through variation in canopy spectral signature. In addition, foliar spectral variation correlates well with variation in canopy chemistry, especially condensed tannins. Variation in aspen canopy chemistry, in turn, is correlated with variation in below-ground processes. Variation in spectra also correlates well with variation in soil traits. These findings indicate that forest tree species can create spatial mosaics of ecosystem functioning across large spatial scales and that these patterns can be quantified via remote sensing techniques. Moreover, they demonstrate the utility of using optical properties as proxies for fine-scale measurements of biodiversity over large spatial scales.

Bird research in the ACWERN lab at the Faculty of Forestry and Environmental Management, University of New Brunswick

2008 ◽  
Vol 84 (4) ◽  
pp. 548-552 ◽  
Author(s):  
Antony W Diamond
Keyword(s):  
New Brunswick ◽  
Forest Cover ◽  
Spatial Scales ◽  
Breeding Habitat ◽  
Research Network ◽  
Spatial Effects ◽  
Winter Habitat ◽  
Forested Landscapes ◽  
Carry Over ◽  
Species Specific

Research on forest bird ecology in the ACWERN (Atlantic Cooperative Wildlife Ecology Research Network) lab at the University of New Brunswick, Fredericton, since 1995 has focused on assessing the relative contributions of habitat quality at large (“landscape”) and small (“local” or “stand”) spatial scales. To do so we had to develop methods for assessing key demographic components of fitness (productivity and survival) at large spatial scales. The large extent of forest cover in the Maritimes contrasts with regions where such work has traditionally been carried out, in which forest is clearly fragmented by agriculture or residential development. Our main findings are that spatial effects in highly forested landscapes can often be detected only by using species-specific habitat models, rather than broader categories such as “mature” or “softwood”, that Blackburnian Warblers (Dendroica fusca) are effective indicators of mixedwood forest but define it differently than forest managers do, and that cavity nesters (e.g., woodpeckers) may require different habitat components for nesting and feeding and so cannot be managed for solely on the basis of providing snags for nesting. Our focus has shifted recently to intensive studies on a species at risk, Bicknell's Thrush (Catharus bicknelli), which in New Brunswick breeds in man-made regenerating softwood forest stands, and assessing its response both to precommercial thinning of the breeding habitat and to effects carrying over from the winter habitat in the Caribbean. Key words: landscape effects, thresholds, survival, productivity, fitness, carry-over, habitat, fragmentation

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