Carabid beetle assemblages on urban derelict sites in Birmingham, UK

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Journal of Insect Conservation 6: 233–246, 2003. © 2003 Kluwer Academic Publishers. Printed in the Netherlands.

Carabid beetle assemblages on urban derelict sites in Birmingham, UK Emma C. Small 1,*, Jon P. Sadler 1 and Mark G. Telfer 2 1

School of Geography and Environmental Sciences, University of Birmingham, Edgbaston, B15 2TT, Birmingham, UK; 2Centre of Ecology and Hydrology, Monks Wood, Abbots Ripton, Peterborough, UK; *Author for correspondence Received 11 June 2002; accepted in revised form 24 January 2003

Key words: Brownfield, Carabidae, Derelict, Succession, Urban ecology Abstract Brownfield sites are thought to support a minimum of 12–15% of Britain’s nationally scarce and rare invertebrates. The amount of derelict land in Britain is set to decrease dramatically under current home-building and regeneration policies. There is therefore a pressing need for research into the potential importance of brownfield sites for invertebrates. In this study we sampled the carabid fauna of 26 sites, with ages varying between 2–20 years since their formation, to assess whether vegetation succession was an important determinant of invertebrate diversity the West Midlands of England. The work was carried out over the course of one growing season (in 1999), with concurrent surveys of the soil characteristics, vegetation type and land-use history. 63 carabid species were found including 2 nationally scarce species. The most species rich assemblages are found on early successional sites, which persist for 6 years on graded sites and up to 20 years on compacted substrates. Introduction Brownfield sites, also referred to as ⬙derelict⬙, ⬙postindustrial⬙, ⬙wasteland⬙ or ⬙ruderal⬙, are habitats, which are fundamentally altered by humans (Gibson 1998). In urban areas, the origin of these sites is principally demolished buildings (eg. houses and factories), although the definition also includes landfills, sand or gravel pits, industrial dumps, former colliery and railway land. According to UK Government statistics, the area of brownfield land in Britain stands at 58,000 hectares (equivalent to the size of the UK West Midlands conurbation) (DETR (Department of Environment, Transport and Regions) 2001). Current policy is to build 60% of the 3.8 million new houses needed in the UK by 2008 on existing brownfield sites in cities. This may well be a cause for concern as brownfields not only provide habitats for eurytopic species in the surrounding urban landscape, but they are important for conserving locally rare species (Kegel 1990; Gruttke 1990), and in some case, national rarities and stenotopic species, which are colonists from semi-natural habitats such as open and dry grasslands (Eversham et al. 1996). In a few studies,

species originating from heathland (Gruttke and Weigman 1990; Andersen 2000) or coastal habitats (Lazenby 1983; Andersen 2000) have been recorded, illustrating the importance of brownfields as analoques for natural habitats. It has been estimated that over 50% of British rare aculeate Hymenoptera and over 35% of British rare and scarce carabid species have been recorded from anthropogenic habitats (Lazenby 1988; Eversham et al. 1996; Gibson 1998). Empirical studies such as the ones undertaken by Lazenby (1983, 1988) who examined the carabid fauna of 65 derelict sites in Sheffield UK, and Schwerk et al. (2000) in the Ruhr Valley in Germany have identified four major types of derelict carabid assemblages, which have clear similarities to the botanical work of Gilbert (1989), who provides a successional model of 4 stages vegetation communities on derelict sites. It is probable that successional processes are important in sustaining and maintaining populations of carabids on brownfields, although the eventual vegetation community is a product of a variety of factors, including the previous land use, substrate and nature of the seed bank. Lott and Daws (1995) and Austin (2002) have shown also that sub-

234 strate influences the speed with which vegetation undergoes succession as well as the identity of the eventual colonists. As such these two components of carabid habitat are therefore closely correlated and we may expect to identify patterns in species distribution according to either or a combination of both. Gilbert (1989) categories are examined using new botanical data from brownfield sites in the West Midlands (Austin 2002), and they are used here to provide a framework for testing the relationship between vegetative components of derelict land sites and the carabid fauna. The aim of this study was to identify the carabid assemblages found on derelict land in the West Midlands in England and determine the extent to which these assemblages can be predicted by the nature of the overlying vegetation and the characteristics of a site, which are favourable to supporting populations of carabid species of conservation significance. The research thus addresses three questions: 1. Are derelict sites characterised by a suite of rare carabids species at local and regional scales? 2. Is vegetation succession an important driving mechanism for carabid assemblage structure? 3. Which site characteristics contribute to the maintenance of populations of rare carabids on derelict land?

strates were mixtures of graded and compacted rubble to rubble dressed with topsoil and nutrient enriched topsoil. Former land-uses on the sites ranged from buildings of some kind (e.g., Factories, housing) to railway land (Table 1). As the activities of the council and locals may affect derelicts sites, resetting the successional processes, we also established when the sites were last disturbed (Age since disturbance) and the nature of that disturbance. Carabid sampling The carabids were sampled by pitfall trapping during four-week trapping periods between mid-April and mid-October 1999. Nine pitfall traps (7 cm diameter plastic cups), part-filled with propylene glycol, were installed at each site. As far as possible, traps were placed in the centre of the site in homogenous stands of vegetation at each site. As the aim was to produce as full a species complement as possible for each site, pitfall trapping was supplemented by 30-minute daytime hand-searches (Andersen 1969), conducted in late May, late June and in late August. Carabids were identified to species using Lindroth (1974). Calathus melanocephalus and C. cinctus were grouped together C. melanocephalus agg. Nebria brevicollis and N. salina as Nebria agg. Habitat variables

Methods Study sites The survey was conducted between mid-April and mid-October 1999. Potential sites were identified using the Joint Development Team (JDT) 1998 register of derelict land in the West Midlands conurbation, but also through reconnaissance surveys of a hundred or more of the JDT sites, and of many more not on the register. Twenty-six derelict sites in the West Midlands conurbation were selected for study (Figure 1), and these were a subset of 52 sites used for a detailed botanical study of plant dynamics on derelict ground (Austin 2002). The study sites, which were between 2–20 years old were characterised by four vegetation communities (Table 1), and represented a vegetation succession gradient, and from early succession (c. 2 years old) to later successional sites with mature species rich grassland and some scrub woodland. Site size varied between 30 ha and the sub-

Site size, in hectares, was obtained from Ordinance Survey maps of the region. Much of the information on the age and previous land-use of the sites was gathered from a questionnaire sent to 30 households around each of the sites, and from aerial photos (City View 1995), the Urban Wildlife Trust and dated Ordinance Survey maps. Fifteen soil samples at 5–10 cm depth were taken from each site in early October 1999. These samples were used to establish mean soil moisture (% weight loss on drying at room temperature) and mean organic matter content (% weight loss on combustion). A mean of 30 readings of the following habitat variables were recorded at each site: soil impenetrability (measured in kgf/cm 2); percentage of bare ground and litter depth (measured in cm). In addition, the plant communities of each of these 26 sites were surveyed in the summer of 1999 and 2000 as part of a partner-project (Austin 2002). The vegetation of three 1 × 1 m quadrats in the trap area was surveyed using a Braun-Blanquet scale. Each quadrat was then matched in Tablefit (Hill 1996) to NVC

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Figure 1. Map of the twenty-six derelict survey sites.

communities and used to provide a vegetation classification for the sites (categories 1–4 in Table 1). Data analysis Information on the habitat preferences, flight ability, breeding season, trophic group and mean body length of each carabid species was derived from Lindroth (1974, 1985, 1986), supplemented by Luff (1998) and Turin (2000). Each species was categorised as preferring (a) dry, open habitats; (b) woodland habitats; (c) damp habitats or (d) being able to exist in a wide variety of habitats (’generalist’), and as being primarily a phytophage; carnivore-small prey (e.g., mites and insect eggs); carnivore-large prey (e.g., slugs and earthworms); or omnivore. Data on the British distribution of each carabid species was derived from Luff (1998). Species trait information and distribution data were also gathered for the 196 species in the ⬙regional species pool⬙, i.e., the species that have been recorded from a 70 × 70 km square centred on the 10-km square SK08 in central Birmingham. As an index of rarity at the national scale, the published conservation

statuses of species (Hyman and Parsons 1992) were used, as well as a count of the number of 10 km squares for each species in the GBRS database (Table 2). The species data were transformed to percentages prior to analysis. The environmental variables were checked for normality using the KolmogorovSmirnov test in SPSS for Windows. Any variables not normally distributed were log-transformed prior to analysis (published 2000). The importance of plant succession on carabid assemblages from our sites was examined in the following manner. The plant communities of 3 1 × 1 m quadrats surveyed in the trap were examined together with the percentage of bare ground recorded, and each site was placed into one of the four groups in line with Gilbert’s (1989) successional model: Bare vegetation (roughly equivalent in structure but not always species composition to Gilbert’s Oxford Ragwort stage); Tall herb; Transitional grassland, and Grassland. The carabid data were ordinated using DECORANA (Hill 1979) and the vegetational data superimposed on this ordination to visually establish

Site

Tyseley Wharf Minworth

Erdington 1

Erdington2

Reservoir Rd Ashted Circus

Soho Loop Heath Street Florence Rd Cape Hill Woodlands1 Woodlands2 Institute Rd Vincent Drivel

Vincent Drive2 Foxyards Rd Landfill Tunnel Street

Hall Green Rd Mounts Rd Old Park Rd

Bentley Mill 1 Bentley Mill 2 M6 Walsall

Brownhills

Site id

D01 D02

D03

D04

D05 D06

D07 D08 D09 D10 D11 D12 D13 D14

D15 D16 D17 D18

D19 D20 D21

D22 D23 D24 D25

D26

Railway line

Sports ground Sports ground Empty Factory/yard

Landfill site Blocks of flats School

Factories Empty Landfill site House/garden

Railway siding Housing Housing Housing Temporary housing Temporary housing Swimming baths Factories

Housing Factory/yard

Garden

House

Factories Sewage works

Previous use

Compacted ballast

Raw brick Graded brick rubble Graded rubble Compacted rubble

Top-soil dumped on rubble Graded brick rubble Compacted rubble

Raw brick Graded rubble Top-soil dumped on rubble Compacted rubble

Compacted ballast Graded brick rubble Graded brick rubble Graded brick rubble Compacted rubble Graded brick rubble Graded brick rubble Compacted rubble

Graded brick rubble Compacted rubble

Graded brick rubble

Graded brick rubble

Top-soil damped on rubble Nutrient rich soil/clay

Substrate

Trampling

Flytipping, fire & garden waste Flytipping, fire & garden waste Mound created during works Flytipping

Trampling, tipping & oil Garden waste & flytipping Flytipping, fire & garden waste

Little Disturbed during roadworks, tipping Compaction by trucks, tipping Compaction by vehicles, tipping

Compaction by vehicles Disturbed during nearby demolition Flytipping, fire & garden waste Flytipping & garden waste Flytipping, fire & trampling Flytipping, fire & trampling Trampling, flytipping, garden waste Trampling

Flytipping, fire & garden waste Compaction by vehicles, tipping

Disturbed during demolition

Flytipping, fire & garden waste

Little Soil dumping and turning

Disturbance since “birth”

Table 1. The twenty-six derelict sites surveyed, their previous use, age, substrate and vegetation.

20

14 14 6 10

10 2 10

15 20 14 10

12 20 8 8 4 4 12 15

15 7

20

4

5 20

20

4 14 6 10

10 2 10

15 5 4 10

12 4 8 8 4 4 12 15

15 7

4

4

5 3

1. Bare/short herb 1. Bare/pioneer grass 1. Bare/weedy grass 1. Bare/pioneer grass 4. Grassland 1. Bare/pioneer grass 3. Transient grass 2. Tall herb 3. Transient grass 4. Grassland 1. Bare/short herb 2. Tall herb 3. Transient grass 1. Bare/weedy grass 2. Tall herb 2. Tall herb 3. Transient grass 1. Bare/weedy grass 4. Grassland 2. Tall herb 1. Bare/weedy grass 1. Bare/tall herb 4. Grassland 2. Tall herb 1. Bare/weedy grass 1. Bare/grass

Age Age since Vegetation classifi(Years) disturbance cation (1–4)

> 30

29.4 29.4 10.5 3.5

38.9 8.5 3.4

10.1 0.7 14.8 1.8

10.3 0.5 5.7 11.4 19.9 19.9 2.0 10.1

1.5 4.2

2.6

5.7

8.7 1.4

Size (HA)

236

26 25 23 22 22 21 21 20 19 19 18 18 18 17 16 15 14 14 14 13 13 13 12 11 11 10 10 10 7 6 6 6

Pterostichus madidus (Fabricius 1775) Harpalus affınis (Schrank) Amara eurynota (Panzer) Nebria brevicollis (Fabricius 1792) Amara lunicollis Schiodte Bembidion lampros (Herbst 1784) Amara communis (Panzer) Trechus quadristriatus (Schrank 1781) Notiophilus biguttatus (Fabricius 1779) Notiophilus substriatus Waterhouse l833 Harpalus rufipes (Degeer) Calathus fuscipes (Goeze 1977) Calathus melanocephalus (L. 1758) Bradycellus verbasci Duft Trechus obtusus Erichson 1837 Amara aulica (Panzer) Amara ovata (Fabricius) Loricera pilicornis (Fabricius 1775) Amara aenea (Degeer) Amara bifrons (Gyll.) Harpalus rubripes (Duftschmid) Dromius linearis (Olivier) Carabus violaceus Linnaeus 1758 Amara familiaris (Duft) Badister bipustulatus Sturm. Amara similata (Gyll.) Bradycellus harpalinus (Serv) Platyderus ruficollis (Marsham 1802) Amara tibialis (Paykull) Bembidion obtusum Serville 1821 Leistus ferrugineus (Linnaeus 1758) Harpalus rufibarbis (Fab.)

Generalist Open Open Generalist Generalist Open Generalist Generalist Generalist Open Open Generalist Open Open Generalist Open Generalist Generalist Open Open Open Open Generalist Open Open Generalist Open Open Open Open Generalist Open

Habitat

**

1 1

*

** **

*

*

*

*

***

Rarity

***Nb ** *

21 13

6

1

26 8 14

11

34

27 2 7 24 2 7 4

10 18 25 6

Sheff Notiophilus aquaticus (Linnaeus 1758) Pterostichus niger (Schaller 1783) Pterostichus strenuus (Panzer 1796) Amara praetermissa (Sahlberg) Amara apricaria (Paykull) Harpalus tardus (Panzer) Asaphidion flavipes (Linnaeus 1761) Metabletus foveatus (Fourcroy) Olisthopus rotundatus (Paykull 1790) Pterostichus melanarius (Illiger 1798) Calathus piceus (Marsham 1802) Bembidion quadrimaculatum (L. 1761) Synuchus nivalis (Panzer 1797) Carabus nemoralis Müller O.F. 1764 Acupalpus meridianus (Linnaeus) Agonum muelleri (Herbst 1784) Anisodactylus binotatus (Fabricius) Amara plejeba (Gyll.) Bembidion guttula (Fabricius 1792) Amara anthobia Villa & Villa Pterostichus cupreus (Linnaeus 1758) Notiophilus palustris (Duftschmid 1812) Bembidion properans Stephens 1828 Agonum dorsale (Pontoppidan 1763) Amara convexior Stephens Bembidion tetracolum Say 1823 Clivina fossor (Linnaeus 1758) Dromius melanocephalus Dejean Pterostichus diligens (Sturm 1824) Pterostichus vernalis (Panzer 1795) Pterostichus versicolor (Sturm 1824) Amara convexiuscula (Marsham)

Species 5 5 5 5 4 4 4 4 4 4 3 3 3 3 3 3 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1

51 30 28 9 24 22 13 12 9 6 18 8 8 6 5 4 6 3 2 30 6 4 3 1 1 1 1 1 1 1 1 1

Open Wood Generalist Open Open Open Open Open Open Generalist Wood Open Generalist Generalist Open Generalist Generalist Generalist Generalist Open Open Generalist Open Open Open Generalist Generalist Open Wet Wet Generalist Coast

Sites Total Habitat

Total number of species: 63. Total number of individuals captured: 12116. Mean individuals per site: 466 (± 596). Mean species per site: 2 1.9 (± 4.1).

6002 605 464 581 523 686 145 218 198 140 507 231 142 92 95 51 284 177 75 93 56 17 87 41 24 78 44 41 36 44 15 9

Sites Total

Species

4

1

2

8

3

2

2

11

Sheff

* ***

***

**

**** *

***

***

**

*

****Nb * **

Rarity

Table 2. Carabid species captured by pitfall and handsearch at the 26 derelict survey sites; their habitat preference (derived from Lindroth (1974) and Luff (1998)) and their national rarity (**** recorded in < 100 GB 10 km squares, *** < 200 squares, ** < 300 squares, * < 400 squares). ⬙Nb⬙ denotes Notable B status from Hyman and Parsons (1992). Species ranked by number of sites where recorded. Open habitat and generalist species (not damp habitat species) captured in Sheffield survey (Lazenby 1983, 1988) also indicated (’Sheff’).

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238 the degree of fit between the two. DCA is a robust technique that provides ordinations that are easily interpretable, and has been used consistently in invertebrate studies in both the UK (Greenwood et al. 1995; Luff et al. 1989; Rushton and Eyre 1992) and elsewhere (Sadler and Dugmore 1995). A Spearman rank correlation was performed to test the relationship between the vegetation groups and the carabid ordination axes and Kruskal-Wallis tests were used to assess the significance of differences in site age, species traits and species compositions between the groups of sites. Site occupancy and rarity was examined by Spearman rank correlations and Kruskal-Wallis tests on substrate and the other habitat variables against the carabids with