Sustainable management systems for unimproved neutral grassland (SUSGRAZ II)
		Duncan Westbury and Stephanie Harris Project overview SUSGRAZ II is a five year Defra funded project (BD1460) investigating the use of sustainable management systems of grazing and hay cutting regimes in extensively managed lowland neutral grassland systems. The project was initiated in April 2007. The research partner and primary grant holder for SUSGRAZ II is the Institute for Grassland and Environmental Research (IGER). This project represents an extension of a previous Defra funded project (Defra BD1440). Objectives SUSGRAZ II aims to identify management systems that will maintain or enhance the abundance of positive indicator plant species of high nature conservation value and control pernicious weed abundance on agriculturally unimproved species-rich lowland grassland. The interactions of these management systems with a suite of sward active invertebrates (spiders and beetles) and insect pollinators is also investigated. Our specific objectives are to: Identify the consequences of applying moderate to lenient continuous grazing pressure over more than 5 successive years for the cover of positive and negative plant indicator species, invertebrate assemblages and cattle performance Identify whether a prolonged period of hay cutting restores botanical diversity, increases positive and controls negative plant indicator species abundance and impacts on invertebrate diversity Identify whether periodic hay cutting of a pasture can provide a practical method for maintaining/restoring botanical diversity, abundance of positive indicator species and control of negative indicator species Examine effects of prolonged or periodic hay cutting on invertebrate assemblages Examine effects of green hay addition and scarification on botanical composition on invertebrate assemblages. Provide sustainable management system(s) for lowland neutral pastures for use in Environmental Stewardship agreements. Overview of experimental methodology These objectives will be tested at the scale of individual fields using a replicated block design. Three principal management practices will be tested. Static grazing management - continuous grazing control: Graze April/May – October to maintain an average sward surface height of 8-10 cm Static hay cut management - cut for hay in July and then graze aftermath with cattle to average sward surface height of – 8-10 cm each year Dynamic management - periodic hay cutting: rotation involving 2 years of hay cutting with aftermath grazing followed by 3 years of grazing only (as in treatment 1) to maintain an average sward height of 8-10 cm throughout the summer (April/May – October). Invertebrate surveys In addition to the botanical and agronomic surveys undertaken by IGER, the Centre for Agri-Environmental Research will undertake detailed surveys. Invertebrate surveys will be undertaken in years 1, 2, 3, and 5 and will be carried out three times yearly to track the phenological development of the sward in response to management and season. Three main groups of invertebrates will be investigated: Phytophagous beetles: Suction samplers will be used to collect leaf beetles (Chrysomelidae) and weevils (Chrysomelidae & Apionidae) which will subsequently be identified to species. Although these taxa show a wide range of host specificities and life history characteristics they are ideal for assessing invertebrate responses to changes in botanical composition in response to the management practices. Spiders: Spiders will be collected at the same time as the phytophagous beetles using the same suction sampler apparatus. However, in contrast to the phytophagous beetles, the spiders are exclusively predatory feeding on small sward active invertebrates. This taxonomic group provides an ideal indicator of the impacts of grazing and hay cutting management on sward structure. Insect pollinators: Butterflies and bumblebees will be surveyed using standard transect methods from the three main treatments to assess visitation preferences and resource utilisation. This group represents providers of key pollination services critical for agricultural production and in many cases their population sizes are in decline nationally. Research PartnerSponsor