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Management of wet grassland habitat to reduce the impact of predation on breeding waders: Phase 1 - BD1324

Description
Populations of waders breeding in lowland wet grassland in England and Wales declined rapidly in the late 20th century and the loss of once widespread species such as lapwing, redshank and snipe from many areas has been of particular conservation concern. Careful management of key sites, most of them nature reserves, has shown that breeding population declines can be halted or even reversed. However, over the same period of time, there has been very little improvement in populations of breeding waders on large areas of wet grasslands managed in line with existing agri-environment agreement prescriptions.

The recovery of wader populations on lowland wet grassland depends to a large extent on the number of young successfully reared to fledging and subsequently recruited into the adult population. One of the main factors that can affect wader breeding success is nest predation. It is possible, therefore, that increases in avian and mammalian predators have hindered the recovery of wader populations in many areas.

Several experimental studies over the last few decades have explored the efficacy of direct predator control in improving the breeding success of various types of birds. Some studies have indicated significant beneficial effects of predator control. Accordingly, predator control can form part of reserve management where the maintenance of healthy breeding bird populations is an objective. Although such practices may be effective at a local scale, they may be impractical at the larger scale and in the longer term of managing land in agri-environment holdings across the whole country. Furthermore, widespread predator control, even if the most effective means of reducing their effect on breeding waders, would be highly controversial. Thus, there is considerable merit in investigating other means by which predation on the nests and chicks of breeding waders might be reduced.

The aim of the present project is to investigate whether habitat modification might be an alternative means by which the impact of predation on breeding waders can be reduced. The rationale of the study is that the way in which predators interact with their prey will be influenced by the way in which both interact with their environment. If it is possible to understand the factors that influence the probability that eggs and chicks will be predated it might be possible to manipulate the environment to reduce predation risk.

We propose to conduct this project in two phases, with Phase 1 being covered in this proposal. In this phase we intend to conduct a thorough literature review and collate and analyse existing data to identify the environmental factors which have the most influence on predator foraging behaviour and wader predation risk. We also propose to use an existing behaviour-based model to construct a framework that will enable us to model the predator-breeding wader system.

In Phase 2 of this project (not covered here), field experiments will be conducted to test hypotheses derived from Phase 1 concerning the efficacy of various forms of habitat manipulation on predation rates. In addition, data from Phase 1 will be used to parameterise the behaviour-based model of predator-breeding wader interactions. This model will be used to predict i) the effects of the experimental habitat manipulations conducted in the field (to test the model) and ii) a range of other habitat manipulations that cannot be carried out in reality within the timespan of this project.

The overall aim of the project is to further our understanding of the efficacy of habitat manipulation as a tool with which to minimise the effects of predation on wader breeding success. This will lead to recommendations that may be utilised by Defra in drawing up future agri-environment management agreements.
Objective
1. Review literature on foraging behaviour and habitat use of avian and mammalian predators of wader nests on lowland wet grassland.
2. Extract and analyse existing data from RSPB databases on wader breeding habitat characteristics, breeding behaviour and levels of nest predation.
3. Design a behaviour-based model which can be used to simulate interactions between predators and breeding waders.
4. Draw up testable hypotheses concerning the role of various environmental factors in influencing predation on wader eggs and chicks and identify data requirements for the predator-breeding wader model.
5. Recommend further research to be undertaken in Phase 2.
6. Prepare a report to Defra describing work undertaken to meet each of Objectives 1-5.
Project Documents
• Final Report : Management of wet grassland habitat to reduce the impact of predation on breeding waders: Phase 1   (290k)
• Final Report - Annex : Management of wet grassland habitat to reduce the impact of predation on breeding waders: Phase 1   (1555k)
Time-Scale and Cost
From: 2005

To: 2006

Cost: £57,528
Contractor / Funded Organisations
Centre for Ecology and Hydrology
Keywords
Agricultural Land              
Environmental Protection              
Grasslands              
Land              
Fields of Study
Environmental Stewardship