scholarly journals Edge function in patchy mussel bed habitats: variation across nearby rocky shore sites

2021 ◽  
Author(s):  
Sabrina Andrea Soria ◽  
Jorge Luis Gutiérrez ◽  
Juliana Andrea Gonzalez ◽  
Sofía Luz Callá ◽  
María Gabriela Palomo
Keyword(s):  
Habitat Structure ◽  
Rocky Shore ◽  
Heat Waves ◽  
Three Dimensional ◽  
Rocky Shores ◽  
Extreme Temperatures ◽  
Mussel Bed ◽  
Invertebrate Composition ◽  
Edge Function ◽  
Habitat Properties

Abstract Mussels form dense three-dimensional beds that serve as habitat to other species. In rocky shores, these beds are often interspersed by gaps due to patchy dislodgement/mortality caused by the action of waves, predators, and/or extreme temperatures. Although mussel patches and gaps are known to support distinctive invertebrate communities, variations in invertebrate habitat function between the interior and edges of mussel patches and gaps were not yet examined. Here, we evaluated variations in habitat properties and invertebrate composition between the edge and interior of mussel (Brachidontes rodriguezii) patches and gaps at three rocky shore sites in the Southwestern Atlantic. Our results indicate that the interior and edge of mussel patches differ in terms of mussel size and density (i.e., a surrogate of habitat structure) and the amount of sediments they accumulate. However, this does not directly translate into consistent differences on temperature, desiccation, and invertebrate composition across sites. As it concerns to gaps, we generally observed increased limpet (Siphonaria lesonii) densities at their edges, which suggests that they encounter favourable conditions by the perimeter of mussel patches. The lack of consistent edge effects on the invertebrates of mussel patches suggests that their species composition would remain largely unaffected by expected increases in gap and edge habitat formation due to ongoing increases in the frequency and magnitude of storms and heat waves. Yet, if increased availability of edge habitats leads to increased overall density of limpets in these rocky shores, then changes could be expected in algal production, composition, and dynamics.

Intensity of Human Predation on Rocky Shores at Las Cruces in Central Chile

1987 ◽  
Vol 14 (2) ◽  
pp. 143-149 ◽  
Author(s):  
L. René Durán ◽  
Juan Carlos Castilla ◽  
Doris Oliva
Keyword(s):  
Activity Pattern ◽  
Rocky Shore ◽  
Rocky Shores ◽  
Central Chile ◽  
Temporal Grouping ◽  
Human Predation

The rocky shore of central Chile is heavily harvested by mariscadores de orilla and skin-divers, but their catches are not considered in the fishery statistics. The aim of the present paper is to estimate the intensity of human predation and annual catch of each of the species taken at Las Cruces, Central Chile. The activity pattern of both categories of collectors demonstrate a temporal grouping. The observation of mariscadores de orilla and skin-divers in 3 sectors of fringe totalling 1,500 m of rocky shore during 12 months allowed us to estimate the annual catch per species caught (kg per year).

scholarly journals Discovery of a new species of genus Typhlodromus Scheuten (Acari: Phytoseiidae: Typhlodrominae) on rocky shore habitat from Lanyu Island

2017 ◽  
Vol 22 (10) ◽  
pp. 1639
Author(s):  
Jhih-Rong Liao ◽  
Chyi-Chen Ho ◽  
Chiun-Cheng Ko
Keyword(s):  
New Species ◽  
Rocky Shore ◽  
Biological Control Agent ◽  
Control Agent ◽  
Morphological Description ◽  
Rocky Shores ◽  
Mountain Areas ◽  
Phytoseiid Mites ◽  
First Time ◽  
A New Species

Phytoseiid mites have been intensively surveyed in Taiwan during the past decades because of their potential as biological control agent. Despite the fact, many regions of Taiwan remain under-explored especially in mountain areas and neighboring islands. Typhlodromus (Anthoseius) crossostephium sp. nov. was collected from Crossostephium chinense (L.) Makino (Asteraceae) on rocky shore habitat during a survey on Lanyu Island. In this paper, presence of a phytoseiid mite on rocky shores is reported for the first time. A detailed morphological description of the new species and a key to the Taiwanese species of subgenus Anthoseius are provided.

scholarly journals The Effect of Habitat Structure Boulder Spacing on Near-Bed Shear Stress and Turbulent Events in a Gravel Bed Channel

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1423
Author(s):  
Amir Golpira ◽  
Fengbin Huang ◽  
Abul B.M. Baki
Keyword(s):  
Shear Stress ◽  
Habitat Structure ◽  
Open Channel ◽  
Reynolds Shear Stress ◽  
Three Dimensional ◽  
Quadrant Analysis ◽  
Bed Shear Stress ◽  
Gravel Bed ◽  
Restoration Practices ◽  
Ejections And Sweeps

This study experimentally investigated the effect of boulder spacing and boulder submergence ratio on the near-bed shear stress in a single array of boulders in a gravel bed open channel flume. An acoustic Doppler velocimeter (ADV) was used to measure the instantaneous three-dimensional velocity components. Four methods of estimating near-bed shear stress were compared. The results suggested a significant effect of boulder spacing and boulder submergence ratio on the near-bed shear stress estimations and their spatial distributions. It was found that at unsubmerged condition, the turbulent kinetic energy (TKE) and modified TKE methods can be used interchangeably to estimate the near-bed shear stress. At both submerged and unsubmerged conditions, the Reynolds method performed differently from the other point-methods. Moreover, a quadrant analysis was performed to examine the turbulent events and their contribution to the near-bed Reynolds shear stress with the effect of boulder spacing. Generally, the burst events (ejections and sweeps) were reduced in the presence of boulders. This study may improve the understanding of the effect of the boulder spacing and boulder submergence ratio on the near-bed shear stress estimations of stream restoration practices.

scholarly journals Population dynamics modify urban residents’ exposure to extreme temperatures across the United States

2019 ◽  
Vol 5 (12) ◽  
pp. eaay3452 ◽  
Author(s):  
Jiachuan Yang ◽  
Leiqiu Hu ◽  
Chenghao Wang
Keyword(s):  
Population Dynamics ◽  
Climate Adaptation ◽  
Heat Waves ◽  
Global Climate ◽  
The United States ◽  
Urban Residents ◽  
Extreme Temperatures ◽  
Mortality And Morbidity ◽  
Spatiotemporal Population Dynamics

Exposure to extreme temperatures is one primary cause of weather-related human mortality and morbidity. Global climate change raises the concern of public health under future extreme events, yet spatiotemporal population dynamics have been long overlooked in health risk assessments. Here, we show that the diurnal intra-urban movement alters residents’ exposure to extreme temperatures during cold and heat waves. To do so, we incorporate weather simulations with commute-adjusted population profiles over 16 major U.S. metropolitan areas. Urban residents’ exposure to heat waves is intensified by 1.9° ± 0.7°C (mean ± SD among cities), and their exposure to cold waves is attenuated by 0.6° ± 0.8°C. The higher than expected exposure to heat waves significantly correlates with the spatial temperature variability and requires serious attention. The essential role of population dynamics should be emphasized in temperature-related climate adaptation strategies for effective and successful interventions.

scholarly journals Associations between Benthic Cover and Habitat Complexity Metrics Obtained from 3D Reconstruction of Coral Reefs at Different Resolutions

2020 ◽  
Vol 12 (6) ◽  
pp. 1011 ◽  
Author(s):  
Atsuko Fukunaga ◽  
John H. R. Burns ◽  
Kailey H. Pascoe ◽  
Randall K. Kosaki
Keyword(s):  
Fractal Dimension ◽  
Coral Reefs ◽  
Habitat Structure ◽  
Coral Cover ◽  
Three Dimensional ◽  
Structural Complexity ◽  
Coralline Algae ◽  
Crustose Coralline Algae ◽  
Surface Areas ◽  
Abundance And Diversity

Quantifying the three-dimensional (3D) habitat structure of coral reefs is an important aspect of coral reef monitoring, as habitat architecture affects the abundance and diversity of reef organisms. Here, we used photogrammetric techniques to generate 3D reconstructions of coral reefs and examined relationships between benthic cover and various habitat metrics obtained at six different resolutions of raster cells, ranging from 1 to 32 cm. For metrics of 3D structural complexity, fractal dimension, which utilizes information on 3D surface areas obtained at different resolutions, and vector ruggedness measure (VRM) obtained at 1-, 2- or 4-cm resolution correlated well with benthic cover, with a relatively large amount of variability in these metrics being explained by the proportions of corals and crustose coralline algae. Curvature measures were, on the other hand, correlated with branching and mounding coral cover when obtained at 1-cm resolution, but the amount of variability explained by benthic cover was generally very low when obtained at all other resolutions. These results show that either fractal dimension or VRM obtained at 1-, 2- or 4-cm resolution, along with curvature obtained at 1-cm resolution, can effectively capture the 3D habitat structure provided by specific benthic organisms.

scholarly journals Rapid response of habitat structure and above-ground carbon storage to altered fire regimes in tropical savanna

2019 ◽  
Vol 16 (7) ◽  
pp. 1493-1503 ◽  
Author(s):  
Shaun R. Levick ◽  
Anna E. Richards ◽  
Garry D. Cook ◽  
Jon Schatz ◽  
Marcus Guderle ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Vegetation Structure ◽  
Habitat Structure ◽  
Canopy Structure ◽  
Three Dimensional ◽  
Canopy Cover ◽  
Fire Regimes ◽  
Dry Season ◽  
Airborne Lidar ◽  
Climate Conditions

Abstract. Fire regimes across the globe have been altered through changes in land use, land management, and climate conditions. Understanding how these modified fire regimes impact vegetation structure and dynamics is essential for informed biodiversity conservation and carbon management in savanna ecosystems. We used a fire experiment at the Territory Wildlife Park (TWP), northern Australia, to investigate the consequences of altered fire regimes for vertical habitat structure and above-ground carbon storage. We mapped vegetation three-dimensional (3-D) structure in high spatial resolution with airborne lidar across 18 replicated 1 ha plots of varying fire frequency and season treatments. We used lidar-derived canopy height and cover metrics to extrapolate field-based measures of woody biomass to the full extent of the experimental site (R2=0.82, RMSE = 7.35 t C ha−1) and analysed differences in above-ground carbon storage and canopy structure among treatments. Woody canopy cover and biomass were highest in the absence of fire (76 % and 39.8 t C ha−1) and lowest in plots burnt late in the dry season on a biennial basis (42 % and 18.2 t C ha−1). Woody canopy vertical profiles differed among all six fire treatments, with the greatest divergence in height classes <5 m. The magnitude of fire effects on vegetation structure varied along the environmental gradient underpinning the experiment, with less reduction in biomass in plots with deeper soils. Our results highlight the large extent to which fire management can shape woody structural patterns in savanna landscapes, even over time frames as short as a decade. The structural profile changes shown here, and the quantification of carbon reduction under late dry season burning, have important implications for habitat conservation, carbon sequestration, and emission reduction initiatives in the region.

Rocky shores and development of the Pliocene-Pleistocene Arroyo Blanco Basin on Isla Carmen in the Gulf of California, Mexico

2006 ◽  
Vol 43 (8) ◽  
pp. 1149-1164 ◽  
Author(s):  
James M Eros ◽  
Markes E Johnson ◽  
David H Backus
Keyword(s):  
Sea Level ◽  
Gulf Of California ◽  
Rocky Shore ◽  
Normal Faults ◽  
Rocky Shores ◽  
Last Interglacial ◽  
Marine Terraces ◽  
Shell Beds ◽  
History Of ◽  
Cap Rock

Arroyo Blanco Basin on Isla Carmen preserves a 157 m thick, nearly complete record of Pliocene–Pleistocene history in the Gulf of California. Examples of rocky-shore geomorphology occur on all margins of this trapezoidal-shaped, 3.3 km2 basin. A shoreline is developed in low relief on Miocene andesite from the Comondú Group at the rear of the basin parallel to the long axis of the island. Two end walls trace normal faults that stayed active during the life of the basin and maintained steep rocky shores. The basin is 64% filled by calcarudite and calcarenite derived from crushed rhodolith debris. Other facies include shell beds and stringers of andesite conglomerate that define a 4°–6° ramp. The ramp expanded onshore through Pliocene time, based on a succession of overlapping range zones for 22 macrofossils typical of Lower through Upper Pliocene strata in the Gulf of California. The unconformity exposed 1 km inland at the rear of the basin is between Miocene volcanics and Pleistocene cap rock at an elevation of 170 m above sea level. Whole rhodoliths encrusted on andesite pebbles occur above this unconformity. Presumably, the older Miocene-Pliocene unconformity is buried beneath the ramp. Four marine terraces with sea cliffs notched in Pliocene limestone occur at elevations of 68, 58, 37, and 12 m. The 12 m terrace is associated regionally with the last interglacial epoch between 120 000 and 135 000 years ago. Juxtaposition of ramp and terrace features in the same exhumed basin supports a long history of gradual Pliocene subsidence followed by episodic Pleistocene uplift.

Recurrence of extreme temperatures in Switzerland from 1965 to 2018

2020 ◽  
Author(s):  
Stefanie Gubler ◽  
Sophie Fukutome ◽  
Christoph Frei
Keyword(s):  
Heat Waves ◽  
Extreme Temperature ◽  
Well Being ◽  
Environmental Research ◽  
Standard Normal Distribution ◽  
Model Parameters ◽  
Strong Impact ◽  
Extreme Temperatures ◽  
The Past ◽  
T Distribution

&lt;p&gt;Extreme high temperatures have a strong impact on human well-being. In Switzerland, for instance, mortality has been shown to increase during strong heat waves (e.g., Ragettli et al., 2017) such as those that occurred in 2003, 2015, or 2018. Knowledge on the recurrence of such heat waves is therefore important, but conventional analysis of observational series is challenged by their rare occurrence (limited sampling), long-term trends, and strong seasonality (non-stationarity). This work presents a methodology, to derive reliable recurrence estimates of extreme maximum and minimum temperature events, taking account of gradual trends and seasonality in the data.&lt;/p&gt;&lt;p&gt;Temperature in Switzerland undergoes pronounced seasonal fluctuations, both in mean value and variance. In addition, a significant warming occurred over the last decades. To derive robust estimates on the rarity of a given extreme temperature event, it is important that these non-stationarities are formally modelled. Our modelling assumes that observed daily temperatures at stations are a superposition of a gradual, non-linear trend and residuals from a skewed T-distribution. The parameters of that distribution are assumed to vary over the year as second order harmonic functions. The model parameters are estimated using maximum likelihood. Thanks to this modelling, the existing daily temperature data can be transformed into a standard normal distribution, and the probability of an event can thus be assessed with respect to the climate at the time of measurement (year, calendar day).&lt;/p&gt;&lt;p&gt;With this methodology in hand, we analyze heat waves of the past, focusing on extreme temperatures at the beginning of summer when mortality risks are higher (Ragettli et al, 2017). We show how the risk of extreme heat has changed in the past, and how very rare events have become much more frequent in the present climate.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Ragettli, M., Vicedo-Cabrero, A. M., Schindler, C., and M. R&amp;#246;&amp;#246;sli (2017): Exploring the association between heat and mortality in Switzerland between 1995 and 2013, Environmental Research, 158, 703-709, https://doi.org/10.1016/j.envres.2017.07.021.&lt;/p&gt;

A Lower Pennsylvanian encrusting tabulate coral from a rocky shore environment developed on the Mississippian—Pennsylvanian unconformity surface in northwestern Arkansas

1993 ◽  
Vol 67 (6) ◽  
pp. 1064-1068 ◽  
Author(s):  
Gregory E. Webb
Keyword(s):  
Rocky Shore ◽  
Wave Attenuation ◽  
High Energy ◽  
Limiting Factors ◽  
Rocky Shores ◽  
Highly Sensitive ◽  
Substrate Stability ◽  
Abundance And Diversity ◽  
High Wave Energy ◽  
Unconformity Surface

Paleozoic corals are very rare in rocky shore settings. The only Paleozoic encrusting coral so far reported from this environment is Favosites sp. from Ordovician rocky shore deposits in Manitoba, Canada (Johnson and Baarli, 1987). Reading and Poole (1961) reported corals and brachiopods that occur between, and “coating,” boulders from a Silurian rocky shore in England, but it appears that the corals and brachiopods only occur in the sediment enveloping the boulders, not as encrusters on the surfaces of the boulders. One reason for the sparse record of Paleozoic corals in rocky shore settings is the scarcity of described Paleozoic rocky shore deposits themselves. Johnson (1988) found only 20 examples of Paleozoic rocky shores in a compilation of references on ancient rocky shores from the literature. The paucity of described ancient rocky shores has been attributed to the prevalence in the past of epicontinental seas with little relief upon which to develop rocky shores and with higher wave attenuation farther from shore (Boucot, 1981; Harland and Pickerill, 1984). Johnson (1988) concluded that the major reason for the rarity of ancient rocky shores in the literature is the difficulty with which they are recognized and studied, owing to the relatively poor exposure of most unconformity surfaces. The rocky shore environment was also probably hostile to many Paleozoic coral genera. Recent scleractinian corals may serve as analogues because they are also not very abundant in rocky shore settings despite their great abundance in similar shallow-water, high-wave-energy reefal environments. Turbidity and relative substrate stability may be important limiting factors for corals in rocky shore environments. Many corals are known to be highly sensitive to sediment in the water column. Substrate stability (Wilson, 1987) and the scouring effects of sand in high-energy environments (Palmer and Palmer, 1977) also have been shown to affect the abundance and diversity of organisms encrusting cobbles and boulders.

scholarly journals Effects of human trampling on a rocky shore fauna on the Sao Paulo coast, southeastern Brazil

2009 ◽  
Vol 69 (4) ◽  
pp. 993-999 ◽  
Author(s):  
MN. Ferreira ◽  
S. Rosso
Keyword(s):  
Rocky Shore ◽  
Management Strategies ◽  
Experimental Studies ◽  
Southeastern Brazil ◽  
Rocky Shores ◽  
Density And Biomass ◽  
Turn Over ◽  
Rocky Shore Communities ◽  
Vacation Period ◽  
Chthamalus Bisinuatus

Increased tourist activity in coastal regions demands management strategies to reduce impacts on rocky shores. The highly populated coastal areas in southeastern Brazil are an example of degradation caused by development of industry and tourism. Among different shore impacts, trampling has been intensively studied, and may represent a significant source of stress for intertidal fauna. A randomised blocks design was applied to experimentally study the effects of two different trampling intensities on richness, diversity, density and biomass of the rocky shore fauna of Obuseiro beach, Guarujá, southeastern Brazil. Blocks were distributed in two portions of the intertidal zone, dominated respectively by Chthamalus bisinuatus (Cirripedia) and Isognomon bicolor (Bivalvia). Blocks were trampled over three months, simulating the vacation period in Brazil and were monitored for the following nine months. Results indicate that Chthamalus bisinuatus is vulnerable to trampling impacts. Richness, diversity and turn-over index tended to be higher in trampled plots four months after trampling ceased. In general, results agree with previous trampling studies, suggesting that even low intensities of trampling may cause some impact on intertidal communities. Management strategies should include isolation of sensitive areas, construction of boardwalks, visitor education and monitoring programmes. In Brazil, additional data obtained from experimental studies are necessary in order to achieve a better understanding of trampling impacts on rocky shore communities.

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