scholarly journals Small Scale Factors Modify Impacts of Temperature, Ice Scour and Waves and Drive Rocky Intertidal Community Structure in a Greenland Fjord

2021 ◽  
Vol 7 ◽  
Author(s):  
Mikael K. Sejr ◽  
Kim N. Mouritsen ◽  
Dorte Krause-Jensen ◽  
Birgit Olesen ◽  
Martin Emil Blicher ◽  
...  
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Physical Stress ◽  
Wave Exposure ◽  
Rocky Intertidal ◽  
Small Scale ◽  
Negative Effects ◽  
Tidal Level ◽  
Intertidal Community ◽  
Invertebrate Species

Understanding the influence of physical drivers and their scale-dependent interactions on ecosystem structure and function is becoming increasingly relevant as ecologists are challenged to quantify and predict the biological implications of anthropogenic activities and climate changes. Here, we aim to quantify the impact of multiple physical drivers (ice scour, wave exposure, and air temperature) and their interactions with small scale modifying factors (tidal level, substrate rugosity, and canopy forming macroalgae) on rocky intertidal community structure. We did this by quantifying intertidal biomass, cover and species richness at three tidal levels (high, mid, and low) at four sites in a sub-arctic Greenland fjord. We found a well-developed intertidal community, with a total of 16 macroalgae and 20 invertebrate species. At one locality, the total biomass was dominated by canopy forming algae exceeding 16 kg wet weight per m–2. Physical stress from ice scour, waves, and air exposure had negative effects on all three community metrics but important interactions and modifying processes were identified. The effect of tidal level differed between sites ranging from an absence of organisms at both high- and mid-intertidal level at the most ice- and wave exposed site to extensive cover across all three tidal levels at the wave and ice sheltered site. Canopy forming macroalgae and substrate rugosity both modified the impacts of physical stress. In the absence of ice scour, canopy forming algae formed extensive cover that modified extreme air temperatures, and the abundance of dominant invertebrate species were all positively related to the biomass of macroalgae. Rugosity provided refuge from ice scour, facilitating increased species richness and cover at exposed sites. Moreover, we detected no negative effects of fast ice, and ice scour impacts were primarily found where presence of glacial ice was combined with wave exposure. Our results provide an example of how large-scale physical factors pass through a filter of several modifying smaller scale processes before their impact on plot scale community structure is manifested.

scholarly journals Disturbance alters ecosystem engineering by a canopy-forming alga

2017 ◽  
Vol 98 (4) ◽  
pp. 687-698 ◽  
Author(s):  
Jacqueline B. Pocklington ◽  
Stuart R. Jenkins ◽  
Alecia Bellgrove ◽  
Michael J. Keough ◽  
Tim D. O'Hara ◽  
...  
Keyword(s):  
Species Richness ◽  
Environmental Conditions ◽  
Ascophyllum Nodosum ◽  
Ecosystem Engineering ◽  
Rocky Intertidal ◽  
Coralline Algae ◽  
Littorina Obtusata ◽  
Invertebrate Species ◽  
Light Levels ◽  
Pulse Disturbance

Canopy-forming fucoid algae have an important role as ecosystem engineers on rocky intertidal shores, where they increase the abundance of species otherwise limited by exposure during low tide. The facilitative relationship between Ascophyllum nodosum and associated organisms was explored using a frond breakage experiment (100%, 50%, 25%, 0% intact-frond treatments) in southern England, to assess the consequences of disturbance. Understorey substratum temperature was on average 3°C higher in 0% and 25% intact-frond treatments than in plots with 50% and 100% intact fronds. Light (as PAR during low tide) doubled in 0% intact-frond treatments in comparison to other treatments (which had similar light levels). Mobile invertebrate species richness declined by on average 1 species per m2 in the treatments with only 25% and 0% intact fronds, and the abundance of Littorina obtusata declined by 2.4–4.2 individuals per m2 in the treatments with 25 and 0% intact fronds. Sessile taxa, including Osmundea pinnatifida and encrusting coralline algae, declined by half on average in the 0% intact-frond treatment. These results suggest that the ability of Ascophyllum to mediate environmental conditions to the understorey is the mechanism responsible for species distributed in the understorey (autogenic ecosystem engineering). The results of this study imply that a pulse disturbance resulting in a 50% breakage of Ascophyllum fronds significantly increases temperature and decreases the abundance of mobile invertebrates usually associated with Ascophyllum. Sessile taxa associated with Ascophyllum can, however, withstand disturbances down to 25% intact Ascophyllum fronds.

scholarly journals Coral communities condition in varying wave exposure: the gulf of Cazones, Cuba

2016 ◽  
Vol 64 (1) ◽  
pp. 79 ◽  
Author(s):  
Hansel Caballero Aragon ◽  
Pedro M Alcolado ◽  
Néstor Rey-Villiers ◽  
Susana Perera Valderrama ◽  
Juliett González Méndez
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Marine Protected Area ◽  
Coral Cover ◽  
Coral Community ◽  
Wave Exposure ◽  
Maximum Diameter ◽  
Live Coral ◽  
Coral Mortality ◽  
Coral Communities

Wave exposure can influence community structure and distribution of shallow coral reefs, by affecting organisms both directly and indirectly. To assess the current stony coral community condition under different degrees of wave exposure at a marine protected area of the Gulf of Cazones (SW Cuba), two expeditions were carried out in May 2010 and June 2012. Four sampling sites were sampled at reef crests (1.5 m deep), and twelve at fore-reefs, at 10, 15 and 20 m deep in four geographic locations. Live coral cover, species richness and composition, colony density, and maximum diameter were assessed using the AGRRA 2001 methodology. Multivariate and non-parametric statistics were applied to compare sites. The coral community structure within reef crests was not homogenous. The observed variability of indicators apparently was determined by great coral mortality events resulting from natural disturbances that occurred in the past (hurricanes, bleaching and diseases). Fore-reef coral communities displayed better condition and lower coral mortality than reef crests. Species richness and coral composition varied, while multivariate and statistical methods did not reveal site grouping with regard to wave exposure. The remaining biological condition indicators were similar among sites, except in the most exposed one, where coral cover and coral size were slightly lower. Wave exposure in the gulf of Cazones seemed not to have a significant influence on differences in condition and structure of the assessed coral communities.

scholarly journals Changes in Rocky Intertidal Community Structure During a Marine Heatwave in the Northern Gulf of Alaska

2021 ◽  
Vol 8 ◽  
Author(s):  
Benjamin Weitzman ◽  
Brenda Konar ◽  
Katrin Iken ◽  
Heather Coletti ◽  
Daniel Monson ◽  
...  
Keyword(s):  
Community Structure ◽  
National Park ◽  
Large Scale ◽  
Monitoring Program ◽  
Gulf Of Alaska ◽  
Marine Ecosystems ◽  
Tourism Industry ◽  
Rocky Intertidal ◽  
Intertidal Communities ◽  
Intertidal Community

Marine heatwaves are global phenomena that can have major impacts on the structure and function of coastal ecosystems. By mid-2014, the Pacific Marine Heatwave (PMH) was evident in intertidal waters of the northern Gulf of Alaska and persisted for multiple years. While offshore marine ecosystems are known to respond to these warmer waters, the response of rocky intertidal ecosystems to this warming is unclear. Intertidal communities link terrestrial and marine ecosystems and their resources are important to marine and terrestrial predators and to human communities for food and recreation, while simultaneously supporting a growing coastal tourism industry. Given that current climate change projections suggest increased frequency and duration of marine heatwaves, monitoring and understanding the impacts of heatwaves on intertidal habitats is important. As part of the Gulf Watch Alaska Long-Term Monitoring program, we examined rocky intertidal community structure at 21 sites across four regions spanning 1,200 km of coastline: Western Prince William Sound, Kenai Fjords National Park, Kachemak Bay, and Katmai National Park and Preserve. Sites were monitored annually from 2012 to 2019 at mid and low tidal strata. Before-PMH (2012–2014), community structure differed among regions. We found macroalgal foundation species declined during this period mirroring patterns observed elsewhere for subtidal habitat formers during heatwave events. The region-wide shift from an autotroph-macroalgal dominated rocky intertidal to a heterotroph-filter-feeder dominated state concurrent with the changing environmental conditions associated with a marine heatwave event suggests the PMH had Gulf-wide impacts to the structure of rocky intertidal communities. During/after-PMH (2015–2019), similarities in community structure increased across regions, leading to a greater homogenization of these communities, due to declines in macroalgal cover, driven mostly by a decline in the rockweed, Fucus distichus, and other fleshy red algae in 2015, followed by an increase in barnacle cover in 2016, and an increase in mussel cover in 2017. Strong, large-scale oceanographic events, like the PMH, may override local drivers to similarly influence patterns of intertidal community structure.

scholarly journals Influence of a breakwater on nearby rocky intertidal community structure

2009 ◽  
Vol 67 (4-5) ◽  
pp. 237-245 ◽  
Author(s):  
Gustavo M. Martins ◽  
André F. Amaral ◽  
Francisco M. Wallenstein ◽  
Ana I. Neto
Keyword(s):  
Community Structure ◽  
Rocky Intertidal ◽  
Intertidal Community

Influence of Static Habitat Attributes on Local and Regional Rocky Intertidal Community Structure

2016 ◽  
Vol 39 (6) ◽  
pp. 1735-1745 ◽  
Author(s):  
B. Konar ◽  
K. Iken ◽  
H. Coletti ◽  
D. Monson ◽  
B. Weitzman
Keyword(s):  
Community Structure ◽  
Rocky Intertidal ◽  
Intertidal Community

Is the species composition of rocky intertidal invertebrates across a biogeographic barrier in south-eastern Australia related to their potential for dispersal?

2007 ◽  
Vol 58 (9) ◽  
pp. 835 ◽  
Author(s):  
Eszter Z. Hidas ◽  
Trudy L. Costa ◽  
David J. Ayre ◽  
Todd E. Minchinton
Keyword(s):  
Species Richness ◽  
Life Histories ◽  
Rocky Intertidal ◽  
Eastern Coast ◽  
Invertebrate Species ◽  
South Eastern ◽  
Constituent Species ◽  
Eastern Australia ◽  
Biogeographic Barrier ◽  
Intertidal Invertebrates

This paper presents the results of surveys quantifying species richness of rocky intertidal invertebrates across a potential biogeographic barrier on the south-eastern coast of Australia, as well as at Red Bluff, which is an isolated rock platform within the otherwise soft-sediment barrier. It was predicted that the number and composition of invertebrate species would differ on either side of the barrier and at Red Bluff and that these differences would be related to the potential for dispersal of the constituent species. Time-per-area searches at two sites within each of five rock platforms on either side of the barrier and at Red Bluff revealed that species richness and composition differed significantly on either side of the barrier, and that Red Bluff supported many species on both sides of the barrier, indicating its potential as a stepping-stone. The distribution of species was not related to their potential for dispersal, because potentially ‘good’ dispersers with planktonic larvae were sometimes restricted to one side of the barrier and potentially ‘poor’ dispersers with direct developing juveniles were present on both sides of the barrier. These results support increasing evidence that the geographic distribution of intertidal invertebrates cannot be inferred by simple reference to their life histories.

Avian community response to small-scale habitat disturbance in Maine

1989 ◽  
Vol 67 (2) ◽  
pp. 385-390 ◽  
Author(s):  
Eric L. Derleth ◽  
Daniel G. McAuley ◽  
Thomas J. Dwyer
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Bird Species ◽  
Forest Edge ◽  
Community Response ◽  
Small Scale ◽  
Avian Community ◽  
Point Counts ◽  
Clear Cut ◽  
Avian Community Structure

The effects of small clearcuts (1–8 ha) on avian communities in the forest of eastern Maine were studied using point counts during spring 1978 – 1981. Surveys were conducted in uncut (control) and clear-cut (treatment) plots in three stand types: conifer, hardwood, and mixed growth. We used a mark –recapture model and its associated jackknife species richness estimator [Formula: see text], as an indicator of avian community structure. Increases in estimated richness [Formula: see text] and Shannon–Weaver diversity (H′) were noted in the treated hardwood and mixed growth, but not in the conifer stands. Seventeen avian species increased in relative abundance, whereas two species declined. Stand treatment was associated with important changes in bird species composition. Increased habitat patchiness and the creation of forest edge are hypothesized as causes for the greater estimates of richness and diversity.

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