Local- and regional-scale effects of wave exposure, thermal stress, and absolute versus effective shore level on patterns of intertidal zonation

2003 ◽  
Vol 48 (4) ◽  
pp. 1498-1508 ◽  
Author(s):  
Christopher D. G. Harley ◽  
Brian S. T. Helmuth
Keyword(s):  
Thermal Stress ◽  
Scale Effects ◽  
Regional Scale ◽  
Wave Exposure ◽  
Shore Level ◽  
Intertidal Zonation

Impacts of road access on lake trout (Salvelinus namaycush) populations: regional scale effects of overexploitation and the introduction of smallmouth bass (Micropterus dolomieu)

2009 ◽  
Vol 66 (2) ◽  
pp. 212-223 ◽  
Author(s):  
Scott D. Kaufman ◽  
Ed Snucins ◽  
John M. Gunn ◽  
Wayne Selinger
Keyword(s):  
Lake Trout ◽  
Scale Effects ◽  
Regional Scale ◽  
Winter Season ◽  
Salvelinus Namaycush ◽  
Smallmouth Bass ◽  
Micropterus Dolomieu ◽  
Excessive Pressure ◽  
Fishing Activity ◽  
Remote Lakes

In lake trout ( Salvelinus namaycush ) lakes of northeastern Ontario, Canada, aerial surveys of fishing activity on individual lakes (N = 589) and quantitative gillnet surveys (N = 65) were used to assess the effects of road access on angling effort and the presence of introduced smallmouth bass ( Micropterus dolomieu ). Angling effort, particularly during the open-water season, was highest and often exceeded estimated sustainable levels on lakes with good road access. Approximately 25% of the remote lakes also received excessive pressure during the winter season. Angler numerical responses to lake trout abundance were detected in remote lakes, but not in road-accessible lakes. Smallmouth bass were more prevalent in lakes with road access and human settlement (either cottages or lodges), supporting the theory that they were introduced into these lakes. Lake trout populations were depleted throughout much of the study range. Even without road access or smallmouth bass, lake trout abundance was still 47% lower than in unexploited reference lakes. When bass and (or) road access were present, lake trout abundance decreased by 77%. Remote lake trout populations in this area are clearly vulnerable to the negative impacts of improved access, a vector for both overexploitation and species introductions.

Patch-, Landscape-, and Regional-Scale Effects on Biota

2002 ◽  
pp. 58-83 ◽  
Author(s):  
Kathryn Freemark ◽  
Daniel Bert ◽  
Marc-André Villard
Keyword(s):  
Scale Effects ◽  
Regional Scale

Small spatial scale effects of wave action exposure on morphological traits of the limpet Lottia subrugosa

2019 ◽  
Vol 99 (06) ◽  
pp. 1309-1315
Author(s):  
Edson A. Vieira ◽  
Marília Bueno
Keyword(s):  
Spatial Scale ◽  
Scale Effects ◽  
Spatial Scales ◽  
Wave Exposure ◽  
Wave Action ◽  
Shell Shape ◽  
Small Scale ◽  
Small Spatial Scale ◽  
Large Spatial Scale ◽  
Exposed Shore

AbstractMany studies have already assessed how wave action may affect morphology of intertidal species among sites that vary in wave exposure, but few attempted to look to this issue in smaller scales. Using the most common limpet of the Brazilian coast, Lottia subrugosa, and assuming position on rocky boulders as a proxy for wave action at small scale, we tested the hypothesis that waves may also influence limpet morphology at a smaller spatial scale by investigating how individual size, foot area and shell shape vary between sheltered and exposed boulder sides on three shores in the coast of Ubatuba, Brazil. Limpets consistently showed a proportionally larger foot on exposed boulder sides for all shores, indicating that stronger attachment is an important mechanism to deal with wave action dislodgement at a smaller scale. Shell shape also varied in the scale investigated here, with more conical (dissipative) shells occurring in exposed boulder sides in one exposed shore across time and in the other exposed shore in one year. Shell shape did not vary regarding boulder sides across time in the most sheltered shore. Although we did not assess large spatial scale effects of wave action in this study, variations of the effect of waves at small spatial scale observed for shell shape suggest that it may be modulated by the local wave exposure regime. Our work highlights the importance of wave action at small spatial scales, and may help to understand the ecological variability of limpets inhabiting rocky shores.

scholarly journals Large-amplitude internal waves benefit corals during thermal stress

2015 ◽  
Vol 282 (1799) ◽  
pp. 20140650 ◽  
Author(s):  
M. Wall ◽  
L. Putchim ◽  
G. M. Schmidt ◽  
C. Jantzen ◽  
S. Khokiattiwong ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Internal Waves ◽  
Coral Bleaching ◽  
Large Amplitude ◽  
Regional Scale ◽  
Total Mortality ◽  
Andaman Sea ◽  
Coral Host ◽  
Conservation Areas ◽  
Sst Anomaly

Tropical scleractinian corals are particularly vulnerable to global warming as elevated sea surface temperatures (SSTs) disrupt the delicate balance between the coral host and their algal endosymbionts, leading to symbiont expulsion, mass bleaching and mortality. While satellite sensing of SST has proved a reliable predictor of coral bleaching at the regional scale, there are large deviations in bleaching severity and mortality on the local scale that are poorly understood. Here, we show that internal waves play a major role in explaining local coral bleaching and mortality patterns in the Andaman Sea. Despite a severe region-wide SST anomaly in May 2010, frequent upslope intrusions of cold sub-pycnocline waters due to breaking large-amplitude internal waves (LAIW) mitigated coral bleaching and mortality in shallow waters. In LAIW-sheltered waters, by contrast, bleaching-susceptible species suffered severe bleaching and total mortality. These findings suggest that LAIW benefit coral reefs during thermal stress and provide local refugia for bleaching-susceptible corals. LAIW are ubiquitous in tropical stratified waters and their swash zones may thus be important conservation areas for the maintenance of coral diversity in a warming climate. Taking LAIW into account can significantly improve coral bleaching predictions and provide a valuable tool for coral reef conservation and management.

scholarly journals Evaluation of effective shore level as a method of characterizing intertidal wave exposure regimes

2006 ◽  
Vol 4 (11) ◽  
pp. 448-457 ◽  
Author(s):  
Sarah E. Gilman ◽  
Christopher D.G. Harley ◽  
Denise C. Strickland ◽  
Olivier Vanderstraeten ◽  
Michael J. O'Donnell ◽  
...  
Keyword(s):  
Wave Exposure ◽  
Shore Level

scholarly journals Coral community bleaching response on a highly urbanised reef

2014 ◽  
Author(s):  
James R Guest ◽  
Jeffrey Low ◽  
Karenne Tun ◽  
Jani I Tanzil ◽  
Peter A Todd ◽  
...  
Keyword(s):  
Community Structure ◽  
Thermal Stress ◽  
Anthropogenic Impacts ◽  
Coral Cover ◽  
Regional Scale ◽  
Coral Community ◽  
Bleaching Response ◽  
Sea Surface Temperature Anomalies ◽  
Relative Cover ◽  
June July

Projected increases in the magnitude and frequency of sea surface temperature anomalies present a significant threat to the persistence of tropical coral reefs, however, detailed studies of community level responses to thermal stress are needed if its effect on reef resilience are to be understood. While many studies report on broad, regional scale responses to thermal stress (e.g., proportion of corals bleached), far fewer examine variation in susceptibility among taxa and change in coral community structure, before, during and after bleaching on individual reefs. Furthermore, relatively few studies of bleaching response come from highly urbanised reefs that experience chronic disturbances such as elevated sedimentation and turbidity. Here we report in detail on the bleaching response of corals at a highly urbanised reef site south of mainland Singapore during (June, July) and immediately after (October) a major thermal coral bleaching event in 2010. To estimate the capacity for resistance and resilience to thermal stress, we report on a) the overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event and c) the response of the reef in terms of taxonomic community structure before (2009) and after (2012) bleaching. Despite severe bleaching in 2010 (66% of colonies bleached), post-bleaching recovery appeared to be relatively rapid and coral taxa that are usually highly susceptible (e.g., Acropora and Pocillopora) were relatively unaffected, i.e., either they did not bleach or they bleached and recovered. Although there was no significant change in coral taxonomic community structure among years, taxa that bleached most severely tended to have the greatest reductions in relative cover. Several factors may have contributed to the overall high resistance of this site to bleaching including turbidity, symbiont affiliation and heterotrophy. A parsimonious explanation for the reversed pattern of bleaching susceptibility among taxa is that these coral populations have adapted and/or acclimatised to thermal stress. Despite ongoing chronic anthropogenic impacts, we suggest that this site has potential for rapid recovery of coral cover due to the dominant coral taxa and growth forms being capable of rapid regrowth from remnant colonies.

Sub-grid scale representation of halogen chemistry in volcanic plumes based on 1D MOCAGE model simulations

2021 ◽  
Author(s):  
Virginie Marécal ◽  
Ronan Voisin-Pessis ◽  
Tjarda Roberts ◽  
Paul Hamer ◽  
Alessandro Aiuppa ◽  
...  
Keyword(s):  
Transport Model ◽  
Scale Effects ◽  
Regional Scale ◽  
Global Scale ◽  
Horizontal Resolution ◽  
Mt Etna ◽  
Modelling Studies ◽  
1D Model ◽  
High Concentrations ◽  
The Impact

<p>Halogen halides emitted by volcanoes are known to rapidly convert within plumes into BrO while depleting ozone, as clearly shown by observations and models over the past 2 decades (e.g. review by Gutmann et al., 2018). So far, most of the modelling studies have focused on the plume processes occurring in the first few hours after the emission. The only study at the regional scale is that of Jourdain et al. (2016). They assessed the impact of volcanic halogens for a period of strong degassing of the Ambrym volcano, showing in particular its effect on the atmospheric oxidizing capacity and methane lifetime.</p><p>A step further would be to quantify the impact of volcanic halogens at the global scale using global chemistry models. This type of model uses a horizontal resolution (greater than 50 km) that is much coarser than the plume size. This raises the issue of, whether at this resolution, it is possible to represent the chemistry occurring under high concentrations within the plume. To assess this, a sub-grid scale parameterization is proposed. It has been tested in the 1D version of MOCAGE global and regional chemistry transport model for a short eruption of Mt Etna on the 10<sup>th</sup> of May 2008. The results show that while using the subgrid-scale plume parameterization or not does change the timing of when the maximum BrO occurs but does not affect the predicted maximum concentration. The same finding is made when using a range of different settings in the parameterization regarding dilution of the plume with its environment. The 1D model results show a sensitivity of BrO formation to parameters other than the sub-grid scale effects: composition of the plume at the vent, injection height of the emissions, and time of the day when the eruption takes place.</p>

8. The Effect of Bythotrephes Longimanus on the Size Structure of Zooplankton Communities in the Muskoka Region, Ontario

2017 ◽  
Author(s):  
Johanna Pokorny
Keyword(s):  
Large Scale ◽  
Size Structure ◽  
Scale Effects ◽  
Regional Scale ◽  
Zooplankton Community ◽  
Zooplankton Abundance ◽  
Bythotrephes Longimanus ◽  
Zooplankton Species ◽  
Community Size ◽  
Zooplankton Communities

Invasive species are considered the greatest threat to aquatic ecosystem biodiversity. Bythotrephes longimanus, an exotic zooplankton species introduced to North America in the 1980s, is threatening the structure of indigenous aquatic ecosystems as it continues to invade inland Ontario lakes. As a predacious zooplankton species, B. longimanus has been shown to decrease zooplankton abundance, species richness and shift zooplankton community size structure in invaded lakes. However, much of the previous research concerning the predatory effects of B. longimanus has been on surveys of a small number of lakes or has been in controlled mesocosm or lab-based experiments. This study examines the effects of B. longimanus on the zooplankton community using size-structure characterizations (grouping individuals from the community based on size) as community measures for 311 lakes in the Muskoka Region, a highly invaded watershed in Southern Ontario. More specifically, the study explores the size-spectra of invaded versus uninvaded lakes, with reference to an array of environmental lake characteristics (water chemistry, lake morphometry,etc.), and the relevance of B. longimanus activity on the regional scale. By using such a large-scale survey we will be able to appreciate regional-scale effects, as well as encompass the multiple and more indirect trophic interactions that B. longimanus is likely having with the entire aquatic community. (Funding: NSERC & CAISN.)

Detecting landscape changes in the interior of British Columbia from 1975 to 1992 using satellite imagery

1998 ◽  
Vol 28 (1) ◽  
pp. 23-36 ◽  
Author(s):  
Donald L Sachs ◽  
Phillip Sollins ◽  
Warren B Cohen
Keyword(s):  
British Columbia ◽  
Landscape Pattern ◽  
Forest Cover ◽  
Scale Effects ◽  
Regional Scale ◽  
Mixed Forest ◽  
Lower Percentage ◽  
Ecological Zones ◽  
Area And Perimeter ◽  
Shape Complexity

To consider the regional scale effects of forest management requires complete and consistent data over large areas. We used Landsat Thematic Mapper and Multispectral Scanner (TM and MSS) imagery to map forest cover and detect major disturbances between 1975 and 1992 for a 4.2 x 106 ha area of interior British Columbia. Forested pixels were mapped into closed conifer, semiopen conifer, deciduous, and mixed forest classes, with further subdivision of the closed conifer type into three age-classes. The image-based estimate of harvested area was similar to an independent estimate from forest inventory data. Changes in landscape pattern from 1975 to 1992 were examined by calculating indices that describe overall landscape pattern and that of conifer and harvested patches in each biogeoclimatic zone. Harvesting affected 8.4% of the forest area outside provincial parks during the 17-year period. Harvested areas were consistently much smaller than conifer patches in all biogeoclimatic zones and had a lower percentage of interior area and perimeter/area ratio. Conifer patch-shape complexity varied between zones; harvested patches had simpler shapes and were similar in all zones. Results indicate that this landscape is only in the early stages of fragmentation, but a similar harvest pattern has been imposed on differing ecological zones.

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