Winterton Dunes NNR

Wonderful Winterton

Winterton is a National Nature Reserve on Norfolk's east coast, comprising acidic sand dune and dune heath ecosystems. The dunes demonstrate ecological succession, with a largely bare sand and shingle beach, gradually becoming colonised by grasses in the sand dunes and developing into heathland with scattered, shrubby areas, and wetter dune slacks. The dunes are home to many migrant and nesting birds, natterjack toads, and insects such as sand wasps, butterflies, and odonata species.


A view of Winterton sand dunes

During our field trip here, we spent the morning exploring various patterns attributed to this succession, by walking a transect from the sea inland through the dunes. We threw quadrats randomly at regular intervals, and recorded the percentage vegetation cover, the number of plant species, and the maximum vegetation height. As expected, we saw an overall increase in vegetation cover and species richness through the dunes, although there was no clear trend in vegetation height.

Lovely Lichen

Some of the prominent species living on the dunes at Winterton are lichens. We designed and carried out a survey to explore the lichen distribution on the dunes, specifically looking into the affect of paths on their population. We decided to sample along three transects from the coast inland, and along each transect we stopped to survey the lichen at each of the first 10 paths we came across. This was intended to ensure a large sample size and better reliability of data. At each path, we placed the quadrat in the middle of the path at three different locations along it, and measured and calculated the average percentage coverage of lichen in the quadrat. We then repeated this for two quadrats adjacent to the path on either side. This again increased the sample size and gave better coverage of the location surveyed, as well as crucially allowing us to compare the lichen distributions on and off the path.

Here is Issy with some lichen on her head!

Here are the results we recorded:


Our results show that there is a weak trend of lichen coverage increasing through the dunes in each case, although this typically decreases towards the end of each of the three transects, and that the coverage can fluctuate significantly. The graphs also show a significant difference between the lichen coverage on and off the paths, with the paths themselves having little to no lichen in almost all the cases with the exception of a few anomalies on the second transect. We can therefore conclude that paths have a significant, detrimental impact on lichen distribution on the sand dunes at Winterton.

This has important repercussions for the management of the sand dunes at Winterton. Our results suggest that reducing the number of paths, i.e. keeping people off the dunes as much as possible would help to conserve and protect the lichen population. However, significantly more research is needed before this conservation action can be recommended. Even for the lichens, the reduction of human disturbance could be detrimental in the long-term, allowing ecological succession to continue to such an extent that the dunes could become so dominated by heather and scrub that it out-competes the smaller lichen species. Furthermore, the lack of human disturbance could negatively affect a wide range of other species, especially those which thrive in early successional stages or who require patches of bare sand, which human footfall is especially good at creating. Not to mention the importance of access to wild spaces for human wellbeing, and to raise awareness and appreciation for the natural world and conservation issues in this way. Therefore, while human disturbance must be kept within reasonable limits, it seems likely that attempting to reduce access and decrease the number of paths through the dunes could in fact negatively impact the sand dune ecosystem.

Cladonia arbuscula

One of the lichen species we encountered at Winterton was Cladonia arbuscula:


Cladonia arbuscula close-up

This species could be identified by its branches pointing in a uniform direction, separating it from the similar Cladonia portentosa. Interestingly it can also be separated by the lack of a UV fluorescence found in C. portentosa! C. arbuscula is widespread on acidic dunes, such as the dune heath at Winterton, as well as montane and lowland heathland environments. It's adapted to well-lit conditions so doesn't survive well on areas of the dunes with larger, taller plant species out-competing it for light. Sadly the species is decreasing due to issues including habitat loss, eutrophication, and as potentially at Winterton, over-protective management causing vegetation overgrowth. This again underscores the need for further research before assuming that paths and human disturbance are a negative force acting at Winterton.

https://britishlichensociety.org.uk/sites/default/files/Cladonia%20arbuscula.pdf


All in all it was a good but very tiring day!



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