Transcript
The Shore Thing – survey procedure and protocol The protocols below are based on those in MCS Marine Field Course Guide ROCKY SHORES, and on discussions with Nova Mieszkowska of MarClim. They have also been field tested by MarLIN.
In order to make accurate and comparative observations The Shore Thing surveys must be done in accordance with the following protocols. Equipment List
Ranging Poles GPS (if available) Compass Digital Camera (if available) Quadrats 0.5 m x 0.5 m Hand Lens Digital Camera
Clipboards Survey Forms Pens and pencils Seashore Guide Waterproof notebook I metre ruler
i) Arrival at shore The area to be surveyed should be photographed from a vantage point whose position is noted to allow the same scene to be captured on subsequent surveys. Find your position on an Ordnance Survey map and enter a six figure grid reference in the first section of the survey form or a GPS reading if available. Brief the group on shore work Health & Safety issues. Run through the survey protocol and ensure groups have survey equipment and recording pro-formas. ii) Transect (see figure 2) The variable under investigation is height above low water mark. The aim is to quantify the assemblage of plants and animals. The most suitable sites for transects are seaward-sloping bedrock – although this will not always be available. The methodology is applicable on wave-cut platforms. Choose an area where transect lines cut across suitable areas of bedrock. Rockpools, fissures, overhangs, areas of boulders and so forth should be avoided because they represent microhabitats that introduce variability in the assemblage of plants and animals which will affect the results. Split the group into teams (ideally of 3) and assign each group to one of three transects (see below). There should be a minimum of three groups. For each transect 12 samples are required (see below) so divide the work up accordingly. All groups should get the chance to sample the lower station. Establish three transects. For each transect the shore should be sampled at three stations; upper, middle and lower shore. Four quadrats should be placed at each station. Ensure that sampling does not overlap from one transect to the next (see figure 2). If there is a severe lack of space, one transect can be run with 10 quadrats at each station. (For statistical usefulness, at least 30 quadrats are required). Lasted updated 03/06/2008
Each group should work for at least 1.5 hours on the transect. It does not matter if the transect line is not straight so long as the stations are similar in terms of wave exposure and not further than a few metres away from the straight line between upper and lower stations. Depending on the timing of high and low tide, students can start at the top of the shore and follow the ebbing tide, or start from low water level at the time of low water. Levelling the shore If working on an ebbing tide, establish the position of the middle station by starting from the upper station and finding the mid-point between high and low tide. For example, if the tidal range from chart datum is 5.4 m, a vertical drop of 2.7 m (5.4 m / 2) from the upper station will locate the middle station. The person at the upper station looks along their pole to the person with the second pole who should be walking towards the sea and then to the horizon. For Figure 1 a vertical drop of 2.7 m, if the person at the upper station looks along the pole at a height of 0.3 m then the horizon needs to be level with the 3.0 m mark on the pole (see figure 1) At the highest station (high water mark roughly indicated by upper limit of barnacles, previous high tide strand line and / or lower limit of lichen) record 3 compass bearings to distant landmarks. This will enable subsequent groups to replicate the same transect. Sampling At least thirty quadrats are required. The upper station should take less time to sample than the middle and lower stations. At each station: a) randomly place a quadrat (0.5m x 0.5m) four times. See figure 2 for a diagrammatic representation. Quadrat placement can be offset from the transect station but ensure that the height above low water is the same, and that there is no overlap with adjacent transect. b) if a digital camera is available, at each station photograph along the shore (normal to the transect line). c) Under each quadrat record: i) Percentage of cover of larger plants (the ‘canopy’ of algae (seaweed) > 15 cm in height). ii) Percentage of rock covered by animals that are attached or encrusting (barnacles, sponges, mussels etc.). iii) Percentage of rock covered by smaller plants (move large algae aside and look at the ‘understorey’ of algae <15 cm in height, including encrusting algae, lichens). iv) Abundance of solitary animals such as limpets, top shells, periwinkles etc. (count Lasted updated 03/06/2008
number of individuals per area). v) All other species where positive identification is possible. See table 1 below for a summary of quantifying species. Table 1. Quantifying abundance of species A. Count individuals Non-colonial animals such as top shells, dogwhelks and limpets Volcano barnacle (Balanus perforatus)
B. Estimate % coverage Barnacle (exception is volcano barnacle, tubeworms Colonial animals such as sponges ansd sea squirts ‘Understorey’ cover by algae <15 cm in height and encrusting algae ‘Canopy’ cover by larger seaweeds > 15 cm in height Lichens
Notes: • Percentages should be estimated down to 10%. Below 10% record P for present • The upper station should be completed quickly as there are fewer species at the top of the shore. Figure 2 - Diagram to illustrate placement of quadrats at three transects with three stations on the shore (Not to scale).
iii) Timed species search This part of the fieldwork is based on a list of ‘target’ species that have been selected because they are easy to identify and are either non-native or indicators of climate change. The species Lasted updated 03/06/2008
in this list have been grouped as likely to occur in different habitats. The search will be carried out in different habitats for an appropriate group of target species. The number each individual searches for will be dependant on the size of the group. No one person should search for more than 3 species. The aim is to provide comparative results by standardizing the time spent searching. Each search is for four different target species on: 1 Open Rock. Search open rock from low to high tide mark 2 Crevice/boulders/overhangs. Search under weed and in nooks and crannies. 3 Rockpools. Search in and around shallow water (wellies essential). Each group of three students will do a search in one of the three habitats. Students should time themselves to spend 20 minutes, recording the abundance of their species at the end of the search. The search should take place as close as possible to low tide. Using the flash cards provided, students should record on their survey form (page 4) abundance as: A (Abundant), F (Frequent), R (Rare) or N (Not found) for each species (see Table 2). These categories correspond with the ACFOR scale used by MarClim 1 . Students should look closely and carefully and investigate under seaweed and overhangs and try not to get distracted by interesting finds – they can go back and look closely after the timed search. Table 2. Abundance of species in the species search Abundant Definitely found at certain level on the shore.
Frequent Definitely found after a little searching.
Rare Intensive search to find 1 or 2 individuals
Not found Not found after searching.
Correct identification of species and of the location in which they were seen (i.e. height on the shore, rock pool, exposed rock and so forth) is very important, so students should check with a teacher / specialist when unsure. It is recommended that students write their reasons for identification in the notes section at the back of the recording form to encourage systematic identification. Photographs should be taken if in doubt. Students should make a note of where and why the photograph was taken. It is vital that all species are searched for. If some are omitted then we cannot conclusively say that they were not found. iv) Results The results of the survey day should be collected and kept safe. Students will be expected to upload them to the MarLIN Web site www.marlin.ac.uk/shore_thing. Once the data has been uploaded the survey forms should be returned to MarLIN to help with validation.
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The ‘Common’ and ‘Occasional’ categories are omitted from the Shore Thing data
Lasted updated 03/06/2008
