Field Trip - Winterton-On-Sea - Trampling and Biodiversity

Last Friday, we visited Winterton-on-Sea, and completed a transect from the beach to approximately 300m inland. We used a quadrat to record a variety of aspects measuring the biodiversity, including the number of species in each quadrat at each site.

When we moved forward to the sample point, Jemima (my partner in the investigation) would just throw the quadrat randomly to avoid biased placing of the quadrat. We then counted the number of species in the quadrat – this was rushed as we had very limited time so was not very accurate and we had to try and count them and then make an educated guess. This is not the most accurate way of measuring but it allowed us to gather enough data to make suggestions about the diversity of the habitat.

The graph shows a rapid initial increase, then a fairly random distribution of data. The initial increase was possibly due to there being more nutrients in the soil as we moved inland, and the conditions became less harsh as it was more sheltered from the shoreline conditions. It is sheltered by the concrete wall that is built along the coast – this is now covered in land so is not visible, rather, it just looks like a small hill. The soil on top of the concrete wall would have a different salinity level and so this may have affected the number of species present and may explain the decrease between sample points 13 and 17. If we had more time, we could have possibly recorded height of sample point above sea level, which is very difficult to measure accurately, and impossibly with the time constraints we had. We could have also measured the pH of the soil and looked at the effect this had, as the pH does decrease further inland. If these constraints weren’t in place I would also identify all the species that are present as then the number of species recorded is a more accurate measurement, rather than just make an estimate. 

Also, to gather a bigger sample size, I would do several transects, possibly three about 15 m apart to get a better idea of the diversity of the whole area. Although we did several transects amongst us as a group and this allowed us to discuss the findings, due to differences in sampling strategies there was great differences in the data. Also, there is the question of which measure of diversity is the best, as it may not be possible to record all in a proper investigation. It is questionable if number of species is the best measurement of species diversity, some may argue that percentage of bare land is a better measure.

We then collected a small amount of data which shows how the number of lichens changes with distance from footpath, to investigate the effect of humans trampling in the dune system. There were many factors to consider when doing this, such as:

• How far away from the path should we measure?
• Should we measure the same distance from the path each time, or do we alter the distance in comparison to width of path? Does this assume people walk off the path more if the path is wider?
• How do you class where the path ends? If using the level of trampling, is a trampling index needed? Do you need to measure the height of the vegetation each time to classify the level of trampling?
• How many paths do you need to measure to get a good sample size?
• Do you need to measure the percentage coverage in each square in the quadrat, to get an idea of how the lichen cover changes over an area or is just using the whole quadrat good enough? But then does this miss out all this information of how the lichen cover gradually changes?

Clearly, it is very difficult to take all these factors into consideration, especially with no prior planning. Although we did not get very much data on lichen coverage due to the fact that we were thinking about all these factors for so long, we did see a difference in the lichen being present off path, whereas on the paths there was none. To conserve this, you could have fewer defined paths, with small barriers either side of the path, or even just pieces of wood to indicate where the paths are, to put people off going off the paths and disturbing the vegetation away from the paths. As lichens are very easily disturbed, this would help increase lichen coverage. You could also have fences to prevent people going on certain areas completely, particularly areas that have been trampled on excessively, and allow them to recover as succession occurs. Information boards could also be placed on these pathways to educate people about why the dune systems need to be conserved, and to highlight the importance of limiting the effect that recreation activities have on the area.