Effects of physical disturbance and canopy cover on attached diatom community structure in an Idaho stream

Hydrobiologia ◽  
1987 ◽  
Vol 154 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Christopher T. Robinson ◽  
Samuel R. Rushforth
Keyword(s):  
Community Structure ◽  
Canopy Cover ◽  
Diatom Community ◽  
Physical Disturbance

VARIATION IN DIATOM COMMUNITY STRUCTURE AMONG HABITATS IN SANDY STREAMS1

1989 ◽  
Vol 25 (4) ◽  
pp. 678-686 ◽  
Author(s):  
R. Jan Stevenson ◽  
Shaharum Hashim
Keyword(s):  
Community Structure ◽  
Diatom Community

scholarly journals Climate change and physical disturbance cause similar community shifts in biological soil crusts

2015 ◽  
Vol 112 (39) ◽  
pp. 12116-12121 ◽  
Author(s):  
Scott Ferrenberg ◽  
Sasha C. Reed ◽  
Jayne Belnap
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Summer Rainfall ◽  
Community Change ◽  
Biological Soil Crusts ◽  
Physical Disturbance ◽  
Precipitation Frequency ◽  
Soil Crusts ◽  
Altered Precipitation

Biological soil crusts (biocrusts)—communities of mosses, lichens, cyanobacteria, and heterotrophs living at the soil surface—are fundamental components of drylands worldwide, and destruction of biocrusts dramatically alters biogeochemical processes, hydrology, surface energy balance, and vegetation cover. Although there has been long-standing concern over impacts of physical disturbances on biocrusts (e.g., trampling by livestock, damage from vehicles), there is increasing concern over the potential for climate change to alter biocrust community structure. Using long-term data from the Colorado Plateau, we examined the effects of 10 y of experimental warming and altered precipitation (in full-factorial design) on biocrust communities and compared the effects of altered climate with those of long-term physical disturbance (>10 y of replicated human trampling). Surprisingly, altered climate and physical disturbance treatments had similar effects on biocrust community structure. Warming, altered precipitation frequency [an increase of small (1.2 mm) summer rainfall events], and physical disturbance from trampling all promoted early successional community states marked by dramatic declines in moss cover and increases in cyanobacteria cover, with more variable effects on lichens. Although the pace of community change varied significantly among treatments, our results suggest that multiple aspects of climate change will affect biocrusts to the same degree as physical disturbance. This is particularly disconcerting in the context of warming, as temperatures for drylands are projected to increase beyond those imposed as treatments in our study.

Feeding ecology of Haloniscus earlei chilton, and Oniscoid Isopod living in Athalassic Saline Waters

1989 ◽  
Vol 40 (3) ◽  
pp. 295 ◽  
Author(s):  
DW Blinn ◽  
SL Blinn ◽  
IAE Bayly
Keyword(s):  
Community Structure ◽  
Feeding Ecology ◽  
The Other ◽  
Diatom Community ◽  
Saline Waters ◽  
Consumption Index ◽  
Periphyton Biomass ◽  
Athalassic Saline Waters

Densities of the oniscoid isopod, Haloniscus searlei Chilton, were orders of magnitude higher on solid substrata than on sediment in the athalassic saline waters of Lake Keilambete and Lake Corangamite, Victoria, Australia. The feeding ecology of H. searlei was examined in the laboratory. Three different grazing densities were employed; one was similar to the estimated density of Haloniscus in the field (c. 212 individuals per m² siderite substratum), and the other two were 3 and 5.5 times higher than field densities, respectively. It was concluded that H. searlei was a very effective grazer. After 2 weeks, treatments with the highest grazing density had 2.5 times less periphyton biomass than treatments at the lowest grazing density and over 3-fold less periphyton than ungrazed controls. Estimated consumption-index values for periphyton were 0.206, 0.124, and 0.096 for treatments ranging from low to high grazing densities. Diatom community structure remained the same in all grazing treatments after 2 weeks. The ability of Haloniscus to use Tanytarsus larvae for food was examined. Cannibalism was also noted.

scholarly journals Recent Changes in the Diatom Community Structure of Lakes in the Beartooth Mountain Range, U.S.A.

2003 ◽  
Vol 35 (1) ◽  
pp. 18-23 ◽  
Author(s):  
Jasmine E. Saros ◽  
Sebastian J. Interlandi ◽  
Alexander P. Wolfe ◽  
Daniel R. Engstrom
Keyword(s):  
Community Structure ◽  
Mountain Range ◽  
Diatom Community

scholarly journals Sandsage prairie: floristics, structure, and dynamics of a Great Plains plant community

2019 ◽  
Vol 13 (1) ◽  
pp. 253-278
Author(s):  
James H. Locklear
Keyword(s):  
Community Structure ◽  
Great Plains ◽  
Fire History ◽  
Management Practices ◽  
Climatic Variability ◽  
Canopy Cover ◽  
Natural Disturbance ◽  
Perennial Grasses ◽  
Artemisia Filifolia ◽  
Shrub Steppe

Sandsage prairie is a shrub-steppe ecological association unique to the Great Plains of North America in which sand sagebrush, Artemisia filifolia, is the dominant and diagnostic element. This paper presents the first comprehensive account of the floristics, community structure, and vegetation dynamics of sandsage prairie throughout its distribution. Sandsage prairie occurs in discontinuous tracts throughout western parts of the central and southern Great Plains in association with dune fields and other areas of sand habitat. The most conspicuous element of the vegetation is shrub-steppe dominated by Artemisia filifolia with a moderate to dense herbaceous layer dominated by perennial grasses. The relative density of Artemisia filifolia canopy cover in the landscape can range from 10% to 50% and is influenced by topographic gradient, climatic variability, fire history, grazing history, and past range management practices. Occurring in mosaic with the shrub-steppe component of sandsage prairie are intergrading but distinct assemblages of herbaceous species tied to varying degrees of disturbance and stabilization within the dune field. A total of 119 plant taxa in 33 families are characteristic of sandsage prairie in the Great Plains, with Poaceae, Asteraceae, Fabaceae, Euphorbiaceae, and Onagraceae the largest families (in descending order). There is a pronounced northsouth gradient to the associated flora, with 34 species (29% of the total) being restricted to or most prevalent in either northern or southern stands of sandsage prairie. Sandsage prairie occurs in highly dynamic habitat subject to a host of natural disturbance factors and as a consequence exhibits a high level of heterogeneity in community structure with frequent shifts in species composition and dominance.

The Effect of Anthropization on Sarcophagidae (Diptera: Calyptratae) Community Structure: An Assessment on Different Types of Habitats in the Humid Chaco Ecoregion of Argentina

2020 ◽  
Vol 57 (5) ◽  
pp. 1468-1479 ◽  
Author(s):  
Matias I Dufek ◽  
Dario D Larrea ◽  
Miryam P Damborsky ◽  
Pablo R Mulieri
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Habitat Type ◽  
Canopy Cover ◽  
Natural Habitats ◽  
Cattle Farm ◽  
Species Richness And Diversity ◽  
Environmental Impact Assessments ◽  
Spatial Turnover ◽  
Main Driver

Abstract Sarcophagidae (Diptera) are of great interest from a veterinary, medical, and forensic viewpoint, and are potential bioindicators for environmental impact assessments. In this study, we evaluated changes in abundance, species richness, and diversity of flesh flies in different habitat types in the Humid Chaco ecoregion of South America: 1) anthropized habitats: urban, cattle farm, and alfalfa crop, and 2) natural habitats: savanna and forest. We hypothesized that sarcophagid fly community parameters are affected by the anthropization and that spatial turnover will contribute more to the overall beta diversity than nestedness between habitats. In each habitat, samplings were conducted monthly from March 2015 to February 2016 in 25 sites, 5 per habitat, totaling 300 independent samples at the end of the study. We collected 5,790 Sarcophagidae (55 species). Community parameters of Sarcophagidae were evaluated and compared. The ecological effects of anthropization and habitat type were observed in the present study. As expected, our results showed the highest abundance, species richness, and diversity in the savanna and forest habitats (natural), whereas the lowest values were registered in the urban and alfalfa crop habitats, supporting the hypotheses of anthropization as the main driver of diversity loss. In addition, sarcophagid assemblages differed between all habitats and the overall dissimilarity was structured by spatial turnover. The main conclusion of this research is that flesh fly community structure is greatly affected by anthropization and habitat type, and this would be related to canopy cover and microclimate conditions of each environment.

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