Rising sea levels, stormier weather, coastal development and more people are putting increasing pressures upon shorebirds that nest on beaches. A paper about the breeding waders of Norfolk & Suffolk (UK) coasts illustrates the importance of understanding human behaviour when trying to maintain (or create) space for breeding plovers. This paper will be of particular interest to conservationists trying to support breeding populations of species such as Ringed Plover, Kentish Plover, Piping Plover and Snowy Plover.
The problems of disturbance
Around the globe, nesting plovers are being threatened by human disturbance. Local initiatives to reduce these impacts include the installation of electric fences, recruiting volunteer wardens and changing local bylaws. You can learn more about which interventions work from Conservation Evidence – there’s more about this at the end of this blog.
Panning out, to look at the bigger picture, is it possible to determine where conflicts between breeding birds and tourists are likely to occur, so that one can try to resolve the problems before they start? Can this information help to inform planning decisions?
Ringed Plovers and Oystercatchers
The coastline of Norfolk and Suffolk should be an ever-changing environment, dominated by sand and shingle beaches. Coastal defences artificially maintain the barrier between sea and land but sea-level rise is predicted to over-top and destroy sea walls during storm events. How will East Anglia’s beach-nesting waders cope with squeezed beaches at the same time as East Anglia is seeing increasing tourist numbers? In a 2020 paper in Global Ecology & Conservation, Jamie Tratalos and colleagues from the University of East Anglia investigated the distributions of nesting Ringed Plovers and Oystercatchers around the beaches of Norfolk and Suffolk, relating settlement patterns to visitor numbers.
Ringed Plovers and Oystercatchers breed on sand and shingle beaches that are also attractive to people. They are prone to disturbance, especially by dogs that are allowed to run free, as discussed by Gómez-Serrano (2021). Nests can be trampled, incubation can be interrupted and chicks can be killed. Liley and Sutherland (2006) showed that, over a 9 km stretch of Norfolk coastline, Ringed Plovers bred less successfully when exposed to disturbance by beach visitors, and population declines in this species have been linked to human disturbance (Birds in England by Brown & Grice, 2005). Human recreation has also been shown to be associated with reduced breeding success in Eurasian and other oystercatcher species (Tjørve & Tjørve, 2010), and Ens and Underhill (2014) suggest that increased human use of the coastal zone, combined with increased risk of nest flooding and loss of wetlands, may threaten the conservation of oystercatchers around the world.
UK breeding populations of Ringed Plover have declined in recent decades, from a conservative estimate of approximately 8400 pairs in 1984 to 4070 in 2007 (Conway et al., 2019) and the species is now red-listed (see the WaderTales blog: Nine red-listed UK waders). Oystercatchers have undergone considerable Europe-wide decline in recent decades and the species has been classified as ‘Near Threatened’ globally (IUCN, 2020).
Counting birds and people
In 2003, when the study at the heart of the Tratalos paper was carried out, East Anglia’s beaches between the Wash and the River Stour held about 3% of the UK’s breeding Ringed Plovers, as well as relatively small numbers of breeding Oystercatchers. As part of a bigger climate change research programme, Tratalos et al were keen to understand what drove the distribution of Ringed Plovers and Oystercatchers, in order to be able to include conservation actions in plans to manage the changing coastline of Norfolk and Suffolk, especially associated the abandonment of outer sea defences. Their research was written up in a 2020 paper in Global Ecology & Conservation.
In the study, the authors examined a 212 km stretch of coastline, mapping all breeding pairs of Ringed Plover and Oystercatcher, as well as the environmental characteristics of beaches. Data on the location of bird territories, and the habitats in which they were found, were collected by Dave Showler in the period between early April and mid-June in 2003. Details of survey methods can be found in the paper.
Visitor numbers to different beaches were assessed by filming from a light aircraft, flying at an altitude of 150 metres. 38,634 human visitors were mapped from three flights during sunny weekends in April, June and August, when the tide was at approximately mid phase. There were pronounced peaks in visitor numbers along the coastline, with 19 of the 1003 beach sections experiencing over 10 times the average number of visitors and 231 sections hosting none.
The key findings from surveys and analyses were:
- Of just over one thousand 200m sections of beach surveyed, 183 beach sections contained Ringed Plover territories (266 breeding pairs) and 117 contained Oystercatcher territories (223 pairs).
- There were more occupied territories in less-visited areas, for both species. See table relating the visitor index to occupation of sectors. An index of 0.13 means that visitor numbers were 13% of the mean across all sectors.
- No Oystercatchers were found breeding in sectors where the visitor index was higher than 2.8. No Ringed Plovers were found in sectors where the index was above 5.5.
- Ringed Plovers territories were more common in sections that had dunes at the back of the beach and where the beaches were broader at low tide.
- Oystercatchers appeared to need space above the high-water mark, as well as a broad intertidal area.
The associations between territories and habitat enabled the team to predict the number of pairs of waders that might have been present in areas which were highly impacted by visitors. If visitor numbers were reduced to zero across the whole study area, breeding potential could be hugely increased.
- The authors predict that there would have been an additional 90 beach sections where Ringed Plovers could potentially establish territories, suggesting that tourism and the local use of beaches has already removed 33% of Ringed Plover breeding habitat.
- There were 96 sections where breeding Oystercatchers might have been expected to be found, so they have already lost 45% of potential habitat.
These results suggest that human activity on beaches influence the location of breeding territories of Ringed Plovers and Oystercatchers, with both species using territories where the number of human visitors was relatively low, when considered both at the scale of the whole Norfolk and Suffolk coast, and locally within areas of this coastline.
In the absence of people, there appear to be clear features of the areas that determine if sectors are used by both wader species for breeding. This makes it possible to predict places where increased access could cause problems so that, ideally, tourism might be encouraged in areas that are less likely to be used by breeding waders. Unfortunately, the beaches that are great for red-listed Ringed Plover – with a back-drop of sand dunes, a sandy beach to walk along at high tide and a gently-shelving intertidal area – are also ones that attract people. This makes it harder to create discrete ‘people zones’ and ‘wader zones’ than might otherwise be the case.
Access points create issues for breeding wader but the effects of most visitors are localised. Unless birdwatching or exercising a dog, the typical tourist will not stray more than 300 metres from a carpark, as indicated in the graphic above. In less-disturbed beach sections, where Oystercatchers set up territories, chicks can hide in upper-beach vegetation until parents indicate that it is safe to come out to be fed.
When Emma Coombes (Global Environmental Change, 2009) asked visitors to Norfolk’s beaches what they were looking for, there was a remarkable consistency in the responses from dog-walkers, sun-bathers and birdwatchers. They all wanted to be on remote flat, sandy beaches, with sand dunes. They would appreciate a car park and toilets too. As soon as such facilities are provided, of course, visitor numbers increase, the remoteness is lost and so are breeding waders, unless fences and wardens are introduced.
Planners have few tools available to them, when it comes to protecting stretches of coastline. All that they can control is development (e.g. new roads, housing and tourist accommodation) and facilities such as car parks and toilets. This paper clearly shows the need to understand the local features that are needed by nesting waders and the importance of documenting current distributions, so that local and national planning authorities have the information they need when planning for the future.
Paper in Global Ecology & Conservation
Regional models of the influence of human disturbance and habitat quality on the distribution of breeding territories of common ringed plover Charadrius hiaticula and Eurasian oystercatcher Haematopus ostralegus. Jamie A. Tratalos, Andy P. Jones, David A. Showler, Jennifer A. Gill, Ian J. Bateman, Robert Sugden, Andrew R. Watkinson & William J. Sutherland.
Before trying a new conservation technique on a local patch, it is worth checking out what has been tried elsewhere. A quick visit to the Conservation Evidence website and a search on ‘beaches’ and ‘bird conservation’ produced a list of 26 actions that have been written up in papers or grey literature. Although many of these interventions are more appropriate to tern conservation than shorebird conservation, a few seem to be particularly relevant to people who are considering how to help breeding Charadrius plovers. Five potential actions are assessed as ‘likely to be beneficial’
- Use signs and access restrictions to reduce disturbance at nest sites
- Physically protect nests with individual exclosures/barriers or provide shelters for chicks of waders
- Protect bird nests using electric fencing
- Physically protect nests from predators using non-electric fencing
- Physically protect nests with individual exclosures/barriers or provide shelters for chicks of ground nesting seabirds
The Conservation Evidence website aims to make scientific research available to conservation practitioners. Anyone considering any of the interventions listed above can see a quick synopsis of what worked (and what didn’t work) in which circumstances. Anyone who has discovered another successful management technique is urged to write up their study – so that it can be added to the database.
WaderTales blogs are written by Graham Appleton (@GrahamFAppleton) to celebrate waders and wader research. Many of the articles are based on published papers, with the aim of making shorebird science available to a broader audience.