Waders for Real seeks to reverse the decline of breeding waders in the Avon Valley, a river floodplain of high biodiversity interest, part of which is designated as a Special Protection Area (SPA). In 1982 the Avon Valley constituted one of the top eight lowland wet grassland sites in England for breeding waders. Since then four surveys at 6-7 year intervals have shown a dramatic decline in numbers of breeding waders, mirroring trends seen across Europe. Numbers of northern lapwing (Vanellus vanellus) pairs have fallen from 208 in 1990 to 71 in 2010. Pairs of redshank (Tringa totanus) have dropped from 117 to 22, and common snipe (Gallinago gallinago) from 29 to one.
Monitoring of lapwing breeding success in the Avon Valley for the last eight years has shown that productivity is currently too low for maintenance of a stable breeding population, owing to high nest predation. To halt the decline of lapwing and redshank, we urgently need to intervene to improve breeding success, which should lead to increases in breeding density.
Wader declines: a pan-European issue
Along with many other farmland birds, breeding waders have been declining across Europe for at least the last 30 years. This is primarily due to agricultural improvement of their favoured wet grassland habitats, involving drainage, fertilisation of grass swards and increases in livestock densities. Agri-environment schemes in several countries have attempted to address these problems by compensating farmers for maintaining higher field water levels and practicing lower intensity farming. However, there is an increasing body of evidence from scientific studies conducted on breeding waders across Europe that high levels of predation by widespread, generalist predators is likely to be limiting wader population recovery in many situations.
There is good evidence from several countries for increases in the numbers of generalist predators such as foxes and corvids over the last 30 years, leading to the situation where, in many cases, habitat restoration alone may not be sufficient to recover wader populations. Analysis of lapwing adult survival rate indicated no appreciable change during 1960-1990 and suggests that insufficient productivity is the main driver of lapwing declines.
There is currently debate at national and international levels on the best way forward to reduce predation on breeding wader clutches and broods and hence ensure that money spent on habitat restoration and management is not wasted. In England, the RSPB, GWCT and Natural England are in agreement that solutions to the low productivity of lapwings and redshank caused by predation are urgently required.
Methods of reducing predator impacts are being developed and trialled by some landowners and other organisations, but these are in large, open landscapes, typically nature reserves. They have focused mainly on predator exclusion fencing. However, this is unlikely to be feasible in all situations, especially river valleys and areas with regular livestock movements, and is only likely to be effective against mammalian predators, not against avian ones.
The Avon Valley is typical of river valley situations where other biodiversity considerations are also important and the feasibility of effectively reducing predator impacts is more constrained by the landscape and multiple land ownership. Our project will inform the national debate by addressing the feasibility of implementing a range of nonlethal anti-predator measures. It will contribute valuable information on the most appropriate techniques, problems encountered and the effort and costs involved.
The decline of waders in the Avon Valley
The Avon Valley has historically supported nationally important populations of breeding northern lapwing (Vanellus vanellus), redshank (Tringa totanus) and common snipe (Gallinago gallinago). In common with other lowland wet grassland sites throughout Britain, the numbers of breeding waders in the Avon Valley have declined dramatically since the early 1980s, with declines of 64% in lapwing, 75% in redshank and 97% in snipe during 1982-2002.
The Avon Valley was designated as an Environmentally Sensitive Area (ESA) in 1993. Since 2003 farmers have been encouraged to join the Higher Level Stewardship (HLS) scheme, and uptake by farmers within the valley has been high. In total, this amounts to a considerable investment in habitat restoration over the last 20 years, but to date there has been no reversal of the trend in wader numbers.
The GWCT has been involved in monitoring breeding waders in the Avon Valley for over 20 years. We hold quantitative data on field conditions and wader numbers and distribution on sites with breeding waders in the Avon Valley in four years: 1990, 1996, 2003 and 2010. Since 2007, we have collected data on lapwing breeding success on 15 farms. Our data for 2007-2014 show clearly that poor breeding success is driving the decline in lapwings and that low nest survival resulting from high levels of predation is the key issue.
Lapwing productivity in the Avon Valley has averaged 0.41 fledged young per pair, reaching a maximum of 0.92 in just one year: this is considerably below the threshold average of 0.7 fledged young per pair per annum needed to maintain a stable population. This is similar to the situation documented in other parts of the UK, e.g. the Norfolk Broads, and in the Netherlands, where mammalian predation on lapwing nests has been recorded at levels where it is limiting population growth.