Baselines and Monitoring Methods for Detecting Impacts of Hydrodynamic Energy Extraction on Intertidal Communities of Rocky Shores

This paper introduces a method for temporal studies of steep rocky intertidal communities. It combines the use of digital image technology with field methodology, so that a wide area of the community can be sampled in a short time. Two current nondestructive percent cover estimation methods (visual estimation and point intersection) were compared in terms of cost, operational advantages and data quality, with a proposed method for a sucessional study . The proposed method used sequential photos to sample multiple fixed vertical transects over time. Reproduction of the mid-intertidal transect over time was possible by overlaying temporal transects in an image editing program. This method was similar to the point intersection quadrat method used to estimate percent cover. Benefits included reduced time on field work, economic advantages and other advantages of using digital photography, such as recording. Temporal photography of transects provided measurements of recruitment, mortality and population growth, and made it possible to manufacture an animation of sucessional stages. We suggest that this is the best method for providing information and understanding on the process of succession and for monitoring benthic invertebrate intertidal communities on steep rocky shores.

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11. Paradigms, Explanations, and Generalizations in Models for the Structure of Intertidal Communities on Rocky Shores

Ecological Communities ◽

10.1515/9781400857081.151 ◽

1984 ◽

pp. 151-180 ◽

Cited By ~ 181

Keyword(s):

Rocky Shores ◽

Intertidal Communities

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Parasitism, community structure and biodiversity in intertidal ecosystems

Parasitology ◽

10.1017/s0031182002001476 ◽

2002 ◽

Vol 124 (7) ◽

pp. 101-117 ◽

Cited By ~ 200

Author(s):

K. N. MOURITSEN ◽

R. POULIN

Keyword(s):

Community Structure ◽

Field Experiments ◽

Population Level ◽

Community Level ◽

Rocky Shores ◽

Intertidal Communities ◽

Metazoan Parasites ◽

Published Evidence ◽

The Impact ◽

Intertidal Ecosystems

There is mounting evidence that parasites can influence the composition and structure of natural animal communities. In spite of this, it is difficult to assess just how important parasitism is for community structure because very few studies have been designed specifically to address the role of parasites at the community level, no doubt because it is difficult to manipulate the abundance of parasites in field experiments. Here, we bring together a large amount of published information on parasitism in intertidal communities to highlight the potential influence of parasites on the structure and biodiversity of these communities. We first review the impact of metazoan parasites on the survival, reproduction, growth and behaviour of intertidal invertebrates, from both rocky shores and soft-sediment flats. Published evidence suggests that the impact of parasites on individuals is often severe, though their effects at the population level are dependent on prevalence and intensity of infection. We then put this information together in a discussion of the impact of parasitism at the community level. We emphasize two ways in which parasites can modify the structure of intertidal communities. First, the direct impact of parasites on the abundance of key host species can decrease the importance of these hosts in competition or predator-prey interactions with other species. Second, the indirect effects of parasites on the behaviour of their hosts, e.g. burrowing ability or spatial distribution within the intertidal zone, can cause changes to various features of the habitat for other intertidal species, leading to their greater settlement success or to their local disappearance. Our synthesis allows specific predictions to be made regarding the potential impact of parasites in certain intertidal systems, and suggests that parasites must be included in future community studies and food web models of intertidal ecosystems.

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X.—Intertidal Communities of the Northern and Western Coasts of Scotland

Transactions of the Royal Society of Edinburgh ◽

10.1017/s0080456800003070 ◽

1956 ◽

Vol 63 (1) ◽

pp. 185-220 ◽

Cited By ~ 19

Author(s):

John R. Lewis

Keyword(s):

Rocky Shores ◽

Intertidal Communities ◽

Low Level ◽

Wide Range

SynopsisAn account is given of the distribution and zonation of the moie important plants and animals found on rocky shores. Particular attention is directed to the variation which occurs in the dominant midlittoral communities of exposed shores, and to the wide range of low-level populations found in the sheltered sea-lochs.

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Persistence of giants: population dynamics of the limpet Scutellastra laticostata on rocky shores in Western Australia

Marine Ecology Progress Series ◽

10.3354/meps13364 ◽

2020 ◽

Vol 646 ◽

pp. 79-92

Author(s):

RE Scheibling ◽

R Black

Keyword(s):

Population Dynamics ◽

Western Australia ◽

Size Structure ◽

Survival Rates ◽

Maximum Size ◽

High Rate ◽

Adult Survival ◽

Rocky Shores ◽

Adult Size ◽

Decadal Time Scale

Population dynamics and life history traits of the ‘giant’ limpet Scutellastra laticostata on intertidal limestone platforms at Rottnest Island, Western Australia, were recorded by interannual (January/February) monitoring of limpet density and size structure, and relocation of marked individuals, at 3 locations over periods of 13-16 yr between 1993 and 2020. Limpet densities ranged from 4 to 9 ind. m-2 on wave-swept seaward margins of platforms at 2 locations and on a rocky notch at the landward margin of the platform at a third. Juvenile recruits (25-55 mm shell length) were present each year, usually at low densities (<1 m-2), but localized pulses of recruitment occurred in some years. Annual survival rates of marked limpets varied among sites and cohorts, ranging from 0.42 yr-1 at the notch to 0.79 and 0.87 yr-1 on the platforms. A mass mortality of limpets on the platforms occurred in 2003, likely mediated by thermal stress during daytime low tides, coincident with high air temperatures and calm seas. Juveniles grew rapidly to adult size within 2 yr. Asymptotic size (L∞, von Bertalanffy growth model) ranged from 89 to 97 mm, and maximum size from 100 to 113 mm, on platforms. Growth rate and maximum size were lower on the notch. Our empirical observations and simulation models suggest that these populations are relatively stable on a decadal time scale. The frequency and magnitude of recruitment pulses and high rate of adult survival provide considerable inertia, enabling persistence of these populations in the face of sporadic climatic extremes.

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