EffectsofinitialsitemanagementontheColeopteraassemblages colonising newly established chalk grassland on ex-arable land SimonR.Mortimer a, *,RogerG.Booth b ,StephanieJ.Harris a ,ValerieK.Brown a a CentreforAgri-EnvironmentalResearch(CAER),DepartmentofAgriculture,UniversityofReading,EarleyGate,POBox236,ReadingRG66AT,UK b CABI Bioscience, Silwood Park, Ascot, Berks SL5 7TA, UK Abstract Largeareasofchalkgrasslandinnorth-westernEuropehavebeenlostasaresultofchangesinlanduse,andtheremainingareas havebecomeincreasinglyfragmented.Consequently,oneofthemajorconstraintsonchalkgrasslandrestorationistheavailability of sources of potential colonists in the landscape. This paper describes a study of the impact of different restoration management techniques on the colonization of new chalk grasslands by Coleoptera. Plots sown with seed mixtures of different diversity were compared with plots undergoing natural plant colonization. A second treatment involved the use of small-scale turf and soil translocation as a means of overcoming dispersal limitation. Significant differences in the Coleoptera assemblages were found in responsetotheexperimentaltreatments.However,thesesignificantdifferencesweretheresultofdifferencesintheabundanceofa small number of common eurytopic grassland species. Four years after the initiation of the restoration management, the experi- mental plots supported very different assemblages in comparison with those found on two established chalk grassland sites in the immediate vicinity of the experimental site. # 2002ElsevierScienceLtd.Allrightsreserved. Keywords: Calcareous grassland; Coleoptera; Colonization; Diversity; England; Festuco-Brometea; Habitat creation; Restoration management 1. Introduction Ecological theory suggests a strong correlation between the diversity of plants and the diversity of higher trophic levels (Hutchinson, 1959; Southwood, 1978). Diversity in the range of food available to con- sumers provides opportunities for niche differentiation amongst primary consumers and other trophic levels. The relationship between plant and insect diversity has been the subject of many studies. Observational and experimental studies have identified linkages between plant diversity and insect diversity (Murdoch et al., 1972;Southwoodetal.,1979;Siemann,1998),andthese have been supported by the results of modelling approaches (Tilman, 1986; Rosenzweig, 1995). How- ever, the relationship between plant and insect diversity may be weak if the apparency of host plant species to their associated insects is limited, especially when the plant species occurs in diverse mixtures (Siemann et al., 1998), or if the host plant patch is small or isolated (Davis and Jones, 1986). The latter is to be expected in early successional situations, such as those associated withhabitatcreationonex-arableland. The chalk grasslands of north-western Europe sup- port a diverse insect fauna (McLean, 1990). The insect assemblages present in chalk grassland are determined not only by the plant species composition, but also by the vertical canopy and horizontal spatial structure of the vegetation (Brown et al., 1990; Mortimer et al., 1998). Some high profile conservation species occur in such grasslands, such as the large blue butterfly (Macu- linea arion; Thomas, 1991), and the wart-biter cricket (Decticus verrucivorus; Cherrill and Brown, 1990). However, in spite of this, there is a paucity of work on the factors controlling the diversity of insects within chalkgrasslands,notableexceptionsbeingthestudiesof Morris and his co-workers (e.g. Morris and Rispin, 1987, 1988). Coleoptera contribute significantly to the diversity of the chalk grassland fauna as a result of the high species number and wide range of ecological types withintheorder(MorrisandRispin,1988). Large areas of chalk grassland have been lost in recent years, primarily as a result of agricultural inten- sification(KeymerandLeach,1990).Inmostareas,the remainingchalkgrasslandfragmentsoccurasislandsin a sea of intensively farmed land. Dispersal of species 0006-3207/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved. PII:S0006-3207(01)00195-1 Biological Conservation 104 (2002) 301–313 www.elsevier.com/locate/biocon * Corresponding author. Tel.: +44-118-931-8475; fax: +44-118- 935-2421. E-mail address: s.r.mortimer@reading.ac.uk (S.R. Mortimer).