The effects of conifer forest design and management on abundance and diversity of rove beetles (Coleoptera: Staphylinidae): implications for conservation

Biological Conservation 1993, 64, 67-76

THE EFFECTS OF CONIFER FOREST DESIGN A N D MANAGEMENT ON A B U N D A N C E A N D DIVERSITY OF ROVE BEETLES (COLEOPTERA: STAPHYLINIDAE): IMPLICATIONS FOR CONSERVATION A. Buse & J. E. G. Good Institute of Terrestrial Ecology, Bangor Research Unit, University College of North Wales, Deiniol Road, Bangor, Gwynedd, UK, LL57 2UP (Received 21 January 1992; revised version received 21 April 1992; accepted 22 May 1992) Abstract The effects of coniferous afforestation, on rove beetles (Coleoptera, Staphylinidae) was investigated in Kielder Forest in 1988 by pitfall and turf sampling in plantations of various age and in unplanted sites. Tree planting decreased habitat availability for most beetles, but provided new habitat for forest species. The greatest abundance, speciesrichness and diversity occurred in non-afforested sites. Site ordination demonstrated an upland group on acid soils and a lowland group on mineral soils, with wet and dry components; species ordination was similar. A central forest group was due to both forest species and original species being maintained. Similarly, classification separated closed-canopy forest sites with little ground vegetation from the remainder. Afforestation had increased habitat diversity by adding trees, rides and roads to the original habitats, but diversity per unit area had decreased. Forest managers should aim to increase staphylinid diversity 'by design', particularly by varying tree species and age class so as to develop greater biological and structural diversity. Habitat diversity could further beenhanced by conserving representative areas of former land use, such as farm fields, river banks and open moorland; active management might be necessary to sustain these. Staphylinid species are favoured by forest edge habitats, so would gain from the integration of small habitat units within plantations, resulting in a beneficial 'knockon' effect by being food for birds and small mammals.

example, was on limestone habitat islands in peat (Bauer, 1989a, b). The lack of studies might be due to difficulties in species identification in such a large group. This study of staphylinid communities in a conifer forest was part of a wide-ranging investigation on the effects of forest design, structure and management on wildlife conservation (Good et al., 1990). Forests in Northern Ireland have been examined for differences in carabid species and number between sitka spruce Picea sitchensis sites of differing ages, from blanket peat, through open canopy to clearfelled (Day & Carthy, 1988). In The Netherlands, deciduous and coniferous forest sites were characterised by their carabid species (Heijerman & Turin, 1989). Staphylinid species, however, have not been used in this way, although they were included in comparisons of oak Quercus and pine Pinus woods (van Der Drift, 1959) and forest and cleaffelled sites (Helle & Muona, 1985). This study examines the numbers and diversity of staphylinid beetles in the vegetation types associated with various planted and unplanted habitats within the forest, including tree crops, felled and restocked areas, roadsides, riversides, rides and unplanted areas. The species' associations at each site are examined, as are the consequent relationships between the sampling sites. The implications of the results for forest management, aimed at improving nature conservation value, are discussed.

Key words: Conifer forest, Staphylinidae, nature conservation, habitat~diversity.

METHODS Study area and related surveys The study area, Kielder Forest in north-east England (Grid ref. NY6690), was about 50 000 ha in extent, of which about 78% was forested (66% plantation; 12% unplanted linear features, mainly rides, roads, rivers and streams). The remainder of the area was unplanted ground. The complete survey, in 1987 and 1988, involved a study of the soils, vegetation, bryophytes, reptiles, amphibians, and invertebrates. The plant communities present in the forest were related to those of the National Vegetation Classification (Rodwell, 1991) (Wallace et al., 1992).

INTRODUCTION

The diversity of rove beetles (Coleoptera: Staphylinidae) and habitats suggests that they would be useful environmental indicators. Kloet and Hincks (1977) list almost 1000 British species and Tottenham 0954) describes their habitats as 'anywhere' and their feeding habits to include carnivorous, fungivorous and phyto-phagous species. In spite of their potential usefulness, there have been few studies of staphylinid communities. One, for Biological Conservation 0006-3207/93/$06.00 © 1993 Elsevier Science Publishers Ltd, England. Printed in Great Britain 67

68

A. Buse, J. E. G. Good Table 1. Characteristics of the sites where beetles were collected by pitfall traps and heat extraction of turf samples

Sample c o d e

Management type

RIDI (NY6782) RID1F (As RID1) RID2 (NY6792) RID2F (as RID2) RID3 (NY6779) RID3F (As RID3) RIVI (NY7499) RIV1F (as RIV1) RIV2 (NY6695)

Ride

Soil

Blanket bog Calluna vulgaris-Eriophorum vaginatum None

Deep peat, pH 3.5

Peaty gley, pH 3.7

1st rotation sitka spruce

Wet heath, Scirpus cespitosus-Erica tetralix and Vaccinium myrtillus None

Peaty gley, pH 3.7

Ride

Rush pasture, Juncus effusus-Galium palustre

Non-peaty gley, pH 5.2

1st rotation sitka spruce

None

Non-peaty gley, pH 4.8

Riverside

Mire, Molinia caerulea-Potentilla erecta

Sandy soil, pH 4.3

Ist rotation sitka spruce Scots pine Riverside

Mire, M. caerulea-P, erecta

Peaty gley, pH 3.8

Mesotrophic grassland, Holcus lanatusDeschampsia cespitosa. Nearby heath, C. vulgaris-V, myrtillus; acid grassland, D. flexuosa Mesotrophic grassland, H. lanatusD. cespitosa; mire, M. caerulea-P, erecta Mire, M. caerulea--P, erecta

Brown earth, pH 5.8

1st rotation sitka spruce Ride

ROAI (NY7881) ROA1F (As ROA1) ROA2 (NY7184)

Roadside

CLF1 (NY7084) CLF2 (NY6786) CLF3 (NY6597) CLP4 (NY6691) UNP1 (NY6396) UNP2 (NY6791) UNP3 (NY6590) ALDER (NY6691)

Restock sitka spruce

NS (t) (NY6392)

Vegetation type(s)

1st rotation Japanese larch Roadside

Restock sitka spruce

Mire, M. caerulea--P, erecta; wet heath, S. cespitosus--E, tetralix; acid grassland, D. flexuosa with V. myrtillus and F. ovinaA. capillaris None

Deep peat, pH 3.5

Peaty skeletal, pH 6.4 Peaty skeletal, pH 4.8 Non-peaty gley, pH 4.1

Stagnopodzol, pH 4.0

Clearfell

Mire, S. cespitosus-E, tetralix with V. myrtillus Mesotrophic grassland, H. lanatusD. cespitosa None

Stagnopodzol, pH 4.1

Unplanted, open moorland

Dry heath, C. vulgaris-V, myrtillus

Deep peat, pH 3.5

Unplanted, rock outcrop

Dry heath, C. vulgaris-V, myrtillus

Peaty skeletal, pH 3-5

Unplanted, meadow

Mesotrophic grassland, H. lanatusD. cespitosa; mire, J. effusus-G, palustre Woodland, Alnus glutinosa, with Quercus robur-Pteridium aquiliniumRubus fruticosus None

Brown podzolic, pH 5.1

Restock Japanese l a r c h

Woodland Thinned Norway spruce

Peaty gley, pH 3.7 Stagnopodzol, pH 4-1

Sandy soil, pH 5.1 Brown podzolic, pH 4-6

RID, ride; RIV, riverside; ROA, roadside; CLF, clearfelledarea with or without restocking; UNP, unplanted areas. Sample codes ending with F refer to paired forest plantation; samples located 15 m into the crop. (), Grid Reference. Study sites The 21 sites were chosen to represent a wide range of forest habitats and associated vegetation types and soils (Table 1) and to provide a range of paired forest and non-forest samples; forest and ride, forest and riverside, forest and roadside, as well as restocks (dearfelled) and various unplanted sites, including moorland, lowland meadow and woodland. Sampling methods

At each of the 21 sites, five pitfall traps, measuring 75 mm diameter at the mouth by 110 mm deep and containing l0 ml of 2% aqueous formalin solution, were set at 2-m intervals along a linear transect to

collect continuously from April to November 1988. This allowed for seasonal differences in the activity of adults (Kasule, 1968). The transects were, as far as possible, placed away from the edge of sites to prevent edge effects of beetles moving from adjacent sites. The traps were emptied at fortnightly intervals, and refilled with formalin solution. This paper examines the staphylinid beetles identified from nine of these collections: 8 and 29 April; 13 May; 1, 15 and 28 June; 26 July; 31 August; and 2 November. The results for the different sampling dates were pooled for each site to provide sufficient numbers for statistical analysis and to remove seasonal differences between the sites. The disadvantages of pitfall trapping, particularly

Abundance and diversity of rove beetles the effects of interspecific differences in behaviour and activity and of differing vegetation or physical conditions on behaviour, are well-known (Buse, 1988). However, pitfall traps do provide a continuous sample throughout the season. To provide a quantitative estimate of the beetle population, albeit of less active and smaller species, five turf samples, measuring 300 x 300 x 100 mm deep, were collected from each site in April and September 1988. The staphylinid beetles were extracted by heat, using Berlese funnels, and all individuals identified. Again, the results were pooled for each site. The species in the April collections were determined by a staphylinid expert (R. C. Welch): other collections were identified by one of the authors (A.B.) and the species confirmed by reference to the named species. Data analysis Differences in the catch size and species richness of staphylinid beetles in the various sites were examined using pooled data from the five pitfalls or five turf samples from the site. The diversity o f species collected at the sites was compared, for the pitfall trapping data, both by comparing the number of species found and using Williams' a index of diversity (Southwood, 1978; Rushton, 1988). Statistical relationships between various aspects of the distribution of the species in the 21 sites were investigated. Correlations between site pH, catch size, species richness and diversity indices were investigated for both

69

pitfall and turf collections. The Mann-Whitney test (Siegl, 1956) was used to examine the relationship between afforestation and catch size, species richness and diversity index. This test, unlike the t-test, does not assume a normal distribution, an appropriate precaution because data collected by pitfall trapping may not be normally distributed. It was also used to compare catches in pairs of sites. The relationships between the species, their groupings in the field, and their relationships with the sampling sites, were examined using VESPAN (Malloch, 1988), a version of D E C O R A N A (Hill, 1979a) and T W l N S P A N (Hill, 1979b). Species of which less than 10 individuals were recorded were excluded from these analyses; thus, 48 species collected by pitfall trapping were included. The presence or absence of these species at each site was used for the analysis. RESULTS Catch size A total of 4003 staphylinid beetles was collected in the pitfall traps and 573 in the turf samples. The distribution between sites of individuals collected from pitfall traps (Table 2) shows the greatest proportion, 15.0% in the roadside ROA1, followed by the unplanted sites UNP3 (13-6%) and UNP2 (10.2%). A similar pattern is shown for individuals extracted from turves (Table 2)--the unplanted site UNP2 (13.8%), the clearfelled site CLF3 (10.7%) and the roadside site ROA2

Table 2. The number of individuals and species of staphylinid beetles collected at each site by pitfall and turf sampling

Site

Individual beetles Pitfall collection No. collected in site

P-.ID1 RID1F RID2 RID2F RID3 RID3F RIV1 RIV1F RIV2 ROA1 ROA1F ROA2 CLF 1 CLF2 CLF3 CLF4 UNP1 UNP2 UNP3 ALDER NS(t) Total

108 90 94 215 113 94 79 101 142 601 260 178 175 57 223 147 116 407 545 106 152 4003

No. of beetle species Turf collection

% of total collection in all sites

No. collected in site

% of total collection in all sites

2.7 2-2 2-3 5.4 2-8 2.3 2.0 2.5 3.5 15.0 6.5 4.4 4.4 1.4 5'6 3.7 2.9 10'2 13.6 2'6 3.8

46 9 33 18 20 11 20 16 8 32 22 59 18 7 61 5 39 79 33 15 22 573

8.0 1.6 5-8 3-1 3-5 1.9 3.5 2'8 1.4 5-6 3-8 10"3 3' 1 1.2 10.7 0.9 6.8 13'8 5.8 2'6 3.8

The interpretation of the site abbreviations is in Table 1.

Pitfall collection

Turf collection

Total

25 13 25 19 13 18 31 24 31 62 28 29 24 17 30 38 11 34 44 23 27

10 5 8 7 8 5 10 8 3 12 7 10 6 5 16 2 9 18 15 6 7

28 15 29 21 20 20 35 27 32 63 31 32 27 18 35 38 15 43 49 26 29

70

A. Buse, J. E. G. Good

Table 3. Comparisons between catch size, species richness and diversity indices and closed-canopy forest and unplanted, closedcanopy forest and rides and closed-canopy and clearfelled sites, resulting from the Mann-Whituey test

Comparisons

Catch size Pitfall Turves Species richness Pitfall Turves Overall Diversity index Pitfall Turves

Closed-canopy forest v. unplanted

Closed-canopy forest v. rides

Closed-canopy forest v. clear-felled

W(5,10)

W(3,3)

W(5,4)

86.598.0*

11.515.0+

25.026.5-

93.599.0* 95.0+

12.515.0+ 13.5-

20.527.020.5-

93.083.5-

12-010.0-

19-026.0-

*, significant at p < 0-05; +, significant at p < 0.10; - , not significant. (10.3%) had the greatest numbers. The generally low abundance in the afforested sites was particularly apparent in the turf samples, for example RID1F with 1'60,6. In spite of these patterns, the comparison of ten unplanted sites with five afforested sites (Table 3) showed that, while the abundance of beetles in the turf samples from unplanted sites was significantly greater (p < 0.05), there was no significant difference in the case of the pitfall samples. There was no significant difference (p < 0.05) in turf or pitfall samples in the comparison between closed-canopy forest sites and their paired rides, or between closed-canopy forest sites and clear-felled areas. These differences are, however, significant a t p < 0.10. Species richness A total of 119 species of staphylinid beetle was recorded from the sampling sites (Appendix 1). The roadside site ROA1 and the unplanted site UNP3--with the greatest number of individuals collected in the pitfall traps--also had the greatest number of species in the pitfall collections (Table 2), i.e. 62 and 44 respectively. Similarly, the turf samples from the unplanted sites UNP2 and UNP3, and the clearfelled site, CLF3, had the greatest number of species as well as the greatest number of individuals (Table 2). The combined number of species for both pitfall and turf samples shows the roadside site ROA1 to have 63 species, the greatest number, followed by two of the unplanted sites, UNP3 with 49 and UNP2 with 43 (Table 2). The unplanted, linear habitat in paired samples yielded more species than the adjacent forest plantation in every case except one (RID3, RID3F), which had equal numbers. The most marked divergence was between a roadside site (ROA1, 63 species) and its adjacent plantation (ROA1F, 31 species). The species richness in the turf samples was significantly greater (p < 0.05) in the unplanted than the afforested sites (Table 3) as was the overall richness (p < 0.10). The greater species richness in the rides than

in their paired forest sites was significant at p < 0-10, but not at p < 0.05. Species diversity The Williams' a diversity index, based on the number of both beetle species and individuals in the pitfall collections (Table 4), showed the riverside site RIV1 to have the greatest diversity, of 18-8. It had a low number of individuals (79) compared with the number of species (31) collected (Table 2). The roadside site ROA1 followed with an index of 17.4: this site had the greatest number of both individuals and species in the pitfall collections. The clearfelled site CLF4 was next, with an index of 16.6. The indices calculated for the turf samples showed the unplanted site UNP3 to be the most diverse, followed by the riverside site RIV1. The former was amongst the Table 4. The Williams a diversity index values for the collections of staphylinid beetles by pitfall trapping and from turves

Site RIDI RIDIF RID2 RID2F RID3 RID3F RIVI RIV1F RIV2 ROAI ROAIF ROA2 CLFI CLF2 CLF3 CLF4 UNP1 UNP2 UNP3 ALDER NS(t)

Diversity index for pitfall trapping data

Diversity index for turf extraction data

10.2 4-2 11.1 5.0 3-8 6-6 18.8 10-0 12.2 17.4 8.0 9.8 7-5 8.2 9.3 16-6 3.0 8.8 11.3 9.0 9-5

3-9 4.7 3.4 4.3 5.0 3-5 8-0 6-4 1-7 7.0 3.6 3.5 3-2 5.0 7.1 1.2 3.7 7.3 10-6 3.7 2.0

See Table 1 for interpretation of site abbreviations.

Abundance and diversity of rove beetles

71

Table 5. The correlation matrix of catch size, species richness and diversity indices for pitfall and turf collections and for site pH Catch size

Catch size Pitfall Turf Species richness Pitfall Turf All Diversity index Pitfall Turf

pH

Pitfall

0.458* -0.247

0.406

0-553** -0.054 0.520"

0.801"** 0.628** 0-842"**

0-366 0-075

0-299 0-569**

Species richness Turf

Pitfall

Turf

0.237 0.860*** 0.359

0-400 0-984***

0-533

0-785*** 0-368

0-095 0.768***

-0-022 0-374

Diversity index All

0-738*** 0-463*

Pitfall

0.191

*, significant at p < 0-05; **, significant at p < 0.01; ***, significant at p < 0-001. sites with the greatest n u m b e r of both species and individuals extracted from the turves. As mentioned above, RIV1 had a high proportion o f different species in comparison with the n u m b e r of individuals collected. This site was followed closely by UNP2, CLF3 and ROA1. In spite o f these differences, the Mann-Whitney test on the diversity indices in closed-canopy forest versus unplanted and closed-canopy versus ride comparisons showed no statistical differences (Table 3).

Relationships between catch size, species richness, diversity and site pH The correlation matrix for catch size, species richness, diversity and site p H (Table 5) showed positive correlation between both catch size and species richness in pitfall samples with pH. There was also correlation

between total species richness and pH. Similarly, catch size and species richness in pitfall traps, and in turves, were highly correlated.

Relationship between individual species and the sites Table 6 shows the results of the comparison of the catch size of individual species between a pair of contrasting groups of sites. These comparisons are for the c o m m o n e r staphylinid species, i.e. those with >9 individuals collected in total. This resulted in 48 species being tested from the pitfall collections and 27 from those extracted by heat. Only those results which are statistically significant at p < 0.10 or better are shown. In all, ten comparisons were significant at p < 0.05, with another 11 significant at p < 0.10. In both the 'all other sites' versus closed-canopy forest

Table 6. Comparisons of the catch size of individual species between unplanted and closed-canopy forest, wet and dry, all other sites and closed-canopy, and lower pH (0-4.0) and higher pH (4.1-6-4), resulting from the Maun-Whitney test Comparison

Source

(Species no.)

Unplanted v. closed-canopy forest

Pitfall Pitfall Turf Turf Pitfall Pitfall Turf Pitfall Pitfall Turf

(9) (40) (35) (T) (5) (14) (15) (9) (40) (T)

Pitfall Pitfall Pitfall Pitfall Pitfall Pitfall Pitfall Turf Turf Turf Turf

(9) (10) (23) (37) (42) (44) (46) (4) (16) (17) (36)

W(10,5) Wet v. dry

W(8,13) All other sites v. closedcanopy forest W06,5) Lower pH v. higher pH

W(9,12)

Species

W

P

Significance

Omalium rugatum Atheta hypnorum Aloconota gregaria Myllaena brevicornis Acidota crenata Lathrobium brunnipes Lathrobium fulvipenne Omalium rugatum A theta hypnorum Othius myrmecophilus

64.5 63.0 95.0 95.5 64-5 111.0 118.5 151.5 152.0 158-5

0.0602 0.0429 0-0643 0-0521 0.0874 0-05 0-0203 0.0420 0-0519 0.0777

+ * + + + * * * + +

Omalium rugatum Syntomium aeneum Quediusfuliginosus Liogluta nitidiuscula Atheta triangulum Ocalea picata Oxypoda annularis Arpedium brachypterum Othius angustus Othius punctulatus Sipalia cireellaris

69-0 46.5 76.0 73-5 75.0 72-5 68-5 125.5 131.5 50.5 45.0

0-0603 0-0175 0.0562 0.0732 0-0465 0-0592 0-0228 0.0398 0.0092 0.0679 0-0101

+ * + + * + * * * + *

Comparisons are only shown where the result was significant. *, significant at p < 0-05; ÷, significant at p < 0.10. The species no. ( ) is as used in Fig. 3 and Appendix 1. (T) indicates that the species was found only in turf samples and therefore has no number in Appendix 1.

A. Buse, J. E. G. Good

72

and the unplanted versus closed-canopy comparisons (Table 6), Omalium rugatum and Atheta hypnorum were significantly more abundant, a t p < 0-10 or better, in the catches from the afforested sites. In the turf samples, Aloconota gregaria and Myllaena brevicornis were significantly more abundant (p < 0.I0) in the unplanted sites, whereas Othius myrmecophilus was more abundant in the forest samples. In the wet versus dry comparison, both Lathrobium brunnipes and Lathrobium fulvipenne were found to be statistically more abundant in the samples from wetter areas, whereas Acidota crenata was more abundant in dry areas (at p < 0-1). There will, of course, be variation within such sites in wetness and dryness. The comparison of lower (<4.1) or higher (>4.0) pH showed only Arpedium brachypterum to be more abundant (p < 0.05) at low pH, that is, in the more upland and acid areas (Table 6). Five species were shown to be more abundant (p < 0.05) in the higher pH sites: another five species were significant at p < 0.10.

Relationships between sites and between species

Site relationships The D E C O R A N A plot of the 21 sites, based on the relationships between the species, tended to divide into two main groups (Fig. 1). The larger group A, with some exceptions such as RID3, seemed to be associated with lower pH. Included in group A were the upland and more acid dry heath, upland bog, acid grassland and afforested sites, with deep peat or peatygley soils. The second group, B, consisted of sites with relatively herb-rich vegetation on more base-rich, predominantly mineral soils, with a higher pH. These included mesotrophic grasslands, lowland mires and woodland. Thus, axis 1 tended to separate into sites of lower pH in the uplands and higher pH at lower altitudes. The distribution of sites on axis 2 appeared to be related to afforestation. The afforested sites, such as ROA1F, RID1F and RIV1F, had low scores on this axis, whereas the unplanted sites UNP1 and UNP2 and the restocked site CLF3, had higher scores. Within

group A, all the first rotational closed-canopy forest sites (RID1F, RID2F, RID3F, RIV1F) were grouped together.

Species relationships The D E C O R A N A plot of the species (numbered in Appendix 1) showed a continuous distribution, with little evidence of discrete groups (Fig. 2). The location of the species can be interpreted by their preferred habitats (based, where noted, on the present study, or otherwise on Joy (1932), Tottenham (1954) or R. C. Welch (pers. comm.)). The species with high scores on axis 1 tended to be lowland species of open habitats and woodland. Open habitats included rotting vegetation (Anotylus rugosus (11); Tachinus subterraneus (32)); grass roots (Quedius fuliginosus (23), Q. picipes (25)), and carrion or fungi (Tachinus laticollis (30), T. signatus (31)), and woodland habitats moss (Philo•thus decorus (18)) and leaf litter (P. laminatus (19)) (Fig. 2). Those species with the lowest scores on axis 1 are characteristic of more upland and acid situations, associated with Sphagnum (Arpedium brachypterum (4); Olophrum fuscum (2), and ants of the genus Myrmica (Drusilla canaliculata (43)). In this study, Arpedium brachypterum (4) is shown to be associated with low pH. The staphylinid species with low and medium scores on axis 2 of Fig. 2 were associated with trees, especially conifers. This group included Omalium rugatum (9) and Atheta hypnorum (40), both found to be statistically more abundant in forest sites in the present study. The species here included Leptusa fumida (33) and L. ruficollis (34), both found under bark, Syntomium aeneum (10) found in moss in woods, and Omalium excavatum (8), Anthobium unicolor (1), and Atheta sodalis (41), all found in dead leaves. Similarly, Mycetoporus clavicornis (27) and M. rufescens (28) are both associated with dead leaves and mycelia. This group of 4001-

6

1o. t 2001-

/

I_43 2 1 -

47+

;

7 036

• • 27 280 46+ 34 ~=18 0 /~ o 13 2 3 - - + ~ 1 1 20 330 3 5 \ ~,~ . i 2 ~ n

A ~LF3

200

45 °

..Alder UNP1 ~ CLF4 IUNP3 ~,r~-~ •UNP2 RIV2 .CLF1 / R I D 2 ~ lOO ~' "'" R&A2 • R I D 1 ; ' \ •~RIV1 B RID2F~ .~,I--/C L F2 RID3F ~ " X~/ • M(:tT~ ~.• /'~ • . . . . . , RID1F R.vlF,,/., ROA1 o I I 0 10o ROA1F 300 Higher pH Lower pH Axis 1

1611~14 48:~2"9+

OQ

Fig. 1. The relationships between the sampling sites resulting from the DECORANA ordination analysis of the pitfalltrapped staphylinid beetle species collected at each. The key to the site abbreviations is in Table 1.

~-20

I 0 Upland

[

[ 20O Axis 1

I

I 400 Lowland

Fig. 2. The relationship between the pitfall-trapped staphylinid beetle species resulting from the DECORANA ordination analysis of the species found at each sampling site. The names of the 48 species numbered are in the Appendix. The symbols indicate (mainly from the literature; see text) the normal habitat of each species: O, moss and Sphagnum, mainly in wet places; O, moss and dead leaves, often in woodland; II, in tufts of grass; r-q, under stones or in the open; and +, in rotting vegetation, vegetable refuse, carrion or fungi.

Abundance and diversity of rove beetles species corresponds with the forest site group observed within the more upland group A (Fig. 1). Species with high scores on axis 2 (Lesteva heeri (6) and L. longoelytrata (7) in moss in wet places and Syntomium aeneum (10) in damp places in woods) were associated with wetter habitats than those with low scores (Lathrobium brunnipes (14), Lathrobium fulvipenne (15), Liogluta nitidiuscula (37), Othius angustus i16)). Both Lathrobium species were significantly more abundant in the drier sites in the present study ITable 6).

,Site classification The TWlNSPAN classification of the sites, by the pitfall-caught staphylinids, separated RIV2, a herbrich, close-grazed riverside site, from all others at the first division (Fig. 3). The indicator species is Philonthus laminatus, usually found in moss under deciduous trees. Its restriction to this site might be due to a relationship with dung: this was the only heavily grazed site. The next division resulted in groups of six and 14 sites. The former contains forest sites, mostly without ground flora. These are grouped closely within group A in Fig. 1. This division is indicated by Omalium rugatum and Atheta hypnorum, both associated with dead leaves and statistically more abundant in forest than unplanted sites (Table 6). In the next division, r.wo closely related sites, ROA1 and ROA1F with pH 6-4 and 4.8, form one group, indicated by Liogluta nitidiuscula, a species associated with moss, and four sites, mainly with little ground vegetation, formed the other group. The indicator species for the remaining 14 sites were Olophrum fuscum, associated with moss, and Anthobium unicolor, associated with moss and dead leaves. These 21

X~lonthus

laminatus

20.~ 1 RIV2 Omalium rugatum/ ~...Olophrum fuscum Othius angustus/ ~..Anthobium unicolor Atheta hypnorurn/ 6

/

,Liogluta \nitidiuscula

Olophrum/ piceum[

\ 4 RID1F RID3F CLF2 NS(T)

14

/ ,DrusiIl~ ] culata

2 ROA1 ROA1F

11 RID2 RID2F RIV1 RIV1F CLF1

3 RID1 RID3 ROA2

CLF 3

CLF4 UNP1 UNP2 UNP3 Alder Fig. 3. The classification of the sampling sites by the TWINSPAN analysis of the pitfall-trapped staphylinid beetle species collected at each. The key to the site abbreviations is in Table 1. (Pseudospecies cut levels 0.00 2.00 4.00 7.00).

73

sites are widespread in Fig. 1. One end group, indicated by Drusilla canaliculata and Olophrum fuscum (both at the upland end of axis 1 in Fig. 2), consisted of three sites: a bog, a wet heath and a rush pasture. The second end group of eleven sites was indicated by the ubiquitous Olophrum piceum. It occurred in 20 of the 21 sites (Appendix l) and is a species of damp heathlands, damp woodland edges, and marsh (Hammond, 1970). Suitable habitat is common throughout this area of high rainfall, resulting in a diverse group of forest, woodland and other sites. This group contrasts with the three wetter sites and the six forest sites with little ground flora. DISCUSSION Effect of habitat Staphylinid beetles feed on decaying matter, living animals, fungi, algae, and plants (Tottenham, 1954; Linssen, 1959). They are considered to be more habitat generalists than other beetle groups: a characteristic confirmed in upland habitats in Wales (Buse, 1988). It is possible that, in Kielder, they might be unaffected by the afforestation of their upland habitats and by the associated management practices (tree-planting, exclusion of domestic grazing animals, ploughing, draining). However, in this study, many staphylinid species were habitat-specific. Unplanted, afforested, wet, dry, low pH and high pH sites each had significantly associated species. There was also a positive correlation between the high pH of lowland and basic sites and the abundance and species richness of their beetles. Relationships with the unplanted sites The relationship between specific species and their habitats was evident at the extreme of the species ordination plot (Fig. 2). The lowland species were associated with basic soils at one end of one axis and the upland species with acidic soils at the other. Similarly, species were associated with the wetter or drier extremes of the second axis. Thus, the unplanted sites, with these habitats, were at the extremes of their plot (Fig. 1). Our groups resembled the invertebrate 'communities' recognised on peat and upland grasslands in northern England by Coulson and Butterfield (1985). Although no forest sites were included in their study, and many of the present sites, being unplanted areas within forest, are smaller, their groups V (upland grassland) and I (lowland mire) correspond with our group B, and their groups III (dry northern heath), II (blanket bog) and IV (edge peat) can be differentiated within our group A. The sites in the unplanted areas of the forest, such as roadsides, rides, and riversides, generally resulted in a greater catch of beetles and of species than the afforested areas. Relationships with afforestation The group of tree-planted sites was in the drier part of the plot of the site ordination (Fig. 1). This central

74

A. Buse, J. E. G. Good

position demonstrates that, despite afforestation blurring site differences (Wallace et al., 1992), they still have similarities with their original communities, and thus with the unplanted sites. Other studies of the community structure of managed forests have similarly shown that tree-planting influences the relationships between sites (Swindel et al., 1990). Some beetles in this central group were associated directly with trees, and were statistically more abundant in the afforested sites. Others were related to the original habitats. The majority, however, were habitat-generalist species which, by implication, would not have specific habitat requirements. Thus, the central position of the afforested sites is due both to the survival of some original species and the addition of new species related to the new management type. This may be enhanced by trees sometimes having no effect on floristic composition during the first ten years after planting (Sykes et al., 1989).

Changes brought about by afforestation Fencing, ploughing, draining and treeplanting directly affect the original habitats. The trees also exert an indirect effect by drying out the soil. This is due mainly to sitka spruce intercepting up to 50% of precipitation (Pyatt & Craven, 1979; Anderson & Pyatt, 1986). This explains the presence of staphylinids of drier habitats and, thus, the position of the forest sites in the ordination. Another indirect effect is the suppression of ground flora by shading and dead leaf accumulation. In some places at Kielder there were major changes in the composition of the ground flora, even though the trees were struggling to survive (Wallace et al., 1992). The reduction in catch size and species in afforested areas could be due to this loss of variety of microhabitats. Heliovaara and Vaisanen (1984) considered that the effects of silvicultural practices on forest invertebrates are transient because insect communities are capable of returning to their original composition. The presence, in our study, of staphylinid species specifically associated with the new habitats introduced by afforestation casts doubt on this view.

Conservation implications Although the new linear habitats of rides and roadsides occupy only about 5% of Kielder forest, they are of disproportionate importance for conservation because they are dispersed throughout the forest. These habitats, together with retained unplanted areas such as riversides, moorland and old fields, have meant that the diversity of habitats, and hence of staphylinid species, has increased since planting. Because the staphylinid fauna of forest is less abundant and species-rich, the overall diversity per unit area has decreased. The habitat and associated faunal diversity of conifer plantations has arisen largely by chance as a result of managers adopting good commercial forest practices in new and second-rotation forests. Much greater diversity can be achieved by design. The differing composition of

the staphylinid communities of the sites studied shows that faunal abundance and species diversity are proportional to the range of habitats available. Planned restructuring involving greater structural diversity, particularly by varying tree species and age class, and with more intimate juxtaposition of different habitats, would favour the dispersion of staphylinids throughout the forest. Leaving areas of different vegetation types unplanted will help conserve assemblages of species which might otherwise be lost. High-altitude mire communities are likely to benefit especially since t h e y are particularly influenced by the drying effect of afforestation. Since many of their species are flightless, recolonisation might be difficult. Such protected areas need to be large enough to hold sustainable populations of beetles, although the minimum size is not known, and should be of various habitat types. Conserving representative areas of former land use, such as farm fields, river banks and open moorland, would further increase habitat diversity. Active management (grazing, cutting or burning) might be necessary to sustain these, and the staphylinid fauna, in their original form. Our study shows that increased habitat diversity in forest plantations would result in increased diversity of beetle species. Similar suggestions have been made for bird species, by dispersing broadleaf trees throughout forests (Bibby et al., 1989), and for lizards, by dispersing wide road verges (Dent & Spellerberg, 1988). Staphylinid diversity at Kielder would similarly be increased if unplanted habitats were widespread in small, but sustainable, units rather than in separate large blocks. Invertebrate studies by Helle and Muona (1985) support the assumption that high breeding bird densities at forest edges may depend on the high invertebrate densities found there. Of the 12 500 ha (20%) of unplanted ground in Kielder forest, 8000 ha are managed wholly or partly for conservation purposes. Of this, 1032 ha consists of 40 mires (Ogilvie, 1990). Most of the conservation areas are, however, large and outside the forest. Smaller units integrated with the plantations would provide more invertebrate-rich 'edges' within the forest, with an accompanying 'knock-on' effect of increased bird and small mammal densities. Land along watercourses is likely to be particularly rich for beetles and should receive high priority for positive management to maintain habitat diversity. ACKNOWLEDGEMENTS We wish to thank Mr Mike Sanderson of the Forestry Commission for collecting the pitfall samples; Dr J. C. Coulson and Dr J. Butterfield of the University of Durham for arranging the extraction of staphylinids from pitfall samples and from turves; and Dr R. C. Welch of the Institute of Terrestrial Ecology's Monks Wood Experimental Station for preparing a reference collection of staphylinid species from the initial Kidder collections, and comments on beetles' habitats and the

Abundance and diversity of rove beetles text. Thanks are also due to Mr T. Sparks, also of ITE, for statistical assistance and advice. We are grateful to Mr G. Patterson of the Forestry Commission and D r K. Kirby of the Nature Conservancy Council (now English Nature) for their helpful comments on the manuscript. The work was undertaken as part of a contract with the Forestry Commission and English Nature.

REFERENCES Anderson, A. R. & Pyatt, D. G. (1986). Interception of precipitation by pole-stage sitka spruce and lodgepole pine and mature sitka spruce at Kielder forest, Northumberland. Forestry, 59, 29-38. Bauer, L. J. (1989a). Moorland beetle communities on limestone 'habitat islands', I. Isolation, invasion and local species diversity in carabids and staphylinids. J. Anita. EcoL, 58, 1077-98. Bauer, L. J. (1989b). Moorland beetle communities on limestone 'habitat islands', II. Flight activity, and its influence on local staphylinid diversity. J. Anim. Ecol., 58, 1099-113. Bibby, C. J., Aston, N. & Bellamy, P. E. (1989). Effects of broadleaved trees on birds of upland conifer plantations in North Wales. Biol. Conserv., 49, 17-29. Buse, A. (1988). Habitat selection and grouping of beetles. Holarct. Ecol., 11,241-7. Coulson, J. C. & Butterfield, J. E. L. (1985). The invertebrate communities of peat and upland grasslands in the north of England and some conservation implications. Biol. Conserv., 34, 197-225. Day, K. R. & Carthy, J. (1988). Changes in carabid beetle communities accompanying a rotation of sitka spruce. Agriculture, Ecosystems & Environment, 24, 407-15. Dent, S. & Spellerberg, I. F. (1988). Use of forest ride verges in southern England for the conservation of the sand lizard Lacerta agilis L. Biol. Conserv., 45, 267-77. Good, J. E. G., Williams, T. G., Wallace, H. L., Buse, A. & Norris, D. A. (1990). Nature Conservation in Upland Conifer Forests. A Report to the Forestry Commission and the Nature Conservancy Council. Institute of Terrestrial Ecology, Bangor. Hammond, P. M. (1970). Notes on British Staphylinidae, 1. The status of Olophrum nicholsoni Donisthorpe with notes on the other British species of Olophrum (Col., Staphylinidae). Entomologist's Monthly Mag., 106, 165-70. Heijerman, T. & Turin, H. (1989). Carabid fauna of some types of forest in the Netherlands (Coleoptera: Carabidae). Tijdschr. Entomol., 132, 241-50. Heliovaara, K & Vaisanen, R. (1984). Effects of modern forestry on northwestern European forest invertebrates: a synthesis. Acta For. Fennica, 189, 1-29. Helle, P. & Muona, J. (1985). Invertebrate numbers in edges between clear-fellings and mature forests in northern Finland. Silva Fennica, 19, 281-94. Hill, M. O. (1979a). DECORANA. A FORTRAN Program for Detrended Correspondence Analysis and Reciprocal Averaging. Cornell University, Ithaca, New York. Hill, M. O. (1979b). TWINSPAN. A FORTRAN Program for Arranging Multivariate Data in an Ordered Two-way Table by Classification of the Individuals and Attributes. Cornell University, Ithaca, New York. Joy, N. H. (1932). A Practical Handbook of British Beetles. Witherby, London. Kloet, G. S. & Hincks, W. D. (1977). A check list of British insects. Coleoptera and Strepsiptera. Hdbk Ident. Brit. Insects, 11(3). Kasule, F. K. (1968). Field studies on the life-histories of some British Staphylinidae (Coleoptera). Trans. Soc. Brit. Entomol., 18, 49-80.

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Linssen, E. F. (1959). Beetles of the British Isles. Warne, London. Malloch, A. J. C. (1988). VESPAN II. A Computer Package to Handle and Analyse Multivariate Species Data and Handle and Display Species Distribution Data. University of Lancaster, Lancaster. Ogilvie, J. F. (1990). Forestry and wetland--conservation of the Border mires. Scott. For., 44, 10-18. Pyatt, D. G. & Craven, M. W. (1979). Soil changes under even-aged plantation. In The Ecology of Even-aged Plantations, ed. E. D. Ford, D. C. Malcolm & J. Atterson. Institute of Terrestrial Ecology, Cambridge, pp. 369-86. RodweU, J. S. (ed.) (1991). British Plant Communities, Vol. 1. Woodlands and Scrub. Cambridge University Press, Cambridge. Rushton, S. P. (1988). The effects of scrub management regimes on the spider fauna of chalk grassland, Castor Hanglands National Nature Reserve, Cambridgeshire, U.K. Biol. Conserv., 46, 169-82. Siegl, S. (1956). Nonparametric Statistics for the Behaviourial Sciences. McGraw-Hill, Tokyo. Southwood, T. R. E. (1978). Ecological Methods with Particular Reference to the Study of Insect Populations, 2nd edn. Chapman and Hall, London. Swindel, B. F., Abt, R. C. & Smith, J. E. (1990). Principal components of variation in community structure of managed forests. J. Environ. Manage., 31, 361~5. Sykes, J. M., Lowe, V. P W. & Brigg, D. R. (1989). Some effects of afforestation on the flora and fauna of an upland sheepwalk during 12 years after planting. J. appl. Ecol., 26, 299-320. Tottenham C. E. (1954). Coleoptera. Staphylinidae. Section (a) Piestinae to Euasthetinae. Hdbk ldent. Brit. Insects, IV(8a). van Der Drift, J. (1959). Field studies on the surface fauna of forests. Meded. Inst. Toegepast Biol. Onderz. Nat., 41, 79-103. Wallace, H. L., Good, J. E. G. & Williams, T. G. (1992). The effects of afforestation on upland plant communities: an application of the British National Vegetation Classification. J. appZ EcoL, 29, 180-94.

APPENDIX 1 The staphylinid species recorded in Kielder forest Micropeplinae Micropeplus fulvus Proteininae Metopsia retusa Megarthrus sinuatocollis Proteinus brachypterus Omaliinae Anthobium atrocephalurn (1) Anthobium unicolor (2) Olophrum fuscum (3) Olophrum piceum Deliphrum tectum (4) Arpedium brachypterum (5) Acidota crenata (6) Lesteva heeri (7) Lesteva longoelytrata Lesteva monticola Lesteva punctata Anthophagus caraboides (8) Omaliurn excavatum Omalium rivulare

NI 536 NI 224 N1 285

Ns 19 Ns 17 N s 20

N I 19 NI 52 Nl 96 NI 26

Ns Ns Ns Ns

Nl 27

Ns 5

5 14 14 7

A. Buse, J. E. G. Good

76 (9) Omalium rugatum

N I 273

N s 14

Nt 19

Nl 11 N I 29

Ns 9 Ns 5 Ns 7

N I 36

Ns 7

Coryphium angusticolle Oxytelinae (10) S yntomium aeneum (11) Anotylus rugosus (12) Anotylus sculpturatus

(29)

Oxytelus laqueatus Steninae (13) Stenus aceris

Stenus bimaculatus Stenus clavicornis Stenus incanus Stenus juno Stenus nigritulus Stenus nitidiusculus Stenus pallitarsis Stenus picipes Stenus rogeri Paederinae (14) Lathrobium brunnipes (15 Lathrobiurn fulvipenne

(30)

(31) (32)

(18) (19)

(20) (21)

(22) (23)

(24) (25) (26)

Atrecus affinis Xantholinus linearis Philonthus decorus Philonthus fimetarius Philonthus laminatus Philonthus marginatus Philonthus nigrita Philonthus varius Staphylinus aeneocephalus Staphylinus erythropterus Staphylinus pedator Quedius boops Quedius curtipennis Quedius fuliginosus Quedius fumatus Quedius nigriceps Quedius nitipennis Quedius maurorufus Quedius molochinus Quedius picipes Quedius picipennis Quedius umbrinus

Tachyporinae (27) Mycetoporus clavicornis

Myceptoporus lepidus Mycetoporus punctus (28) Mycetoporus rufescens Mycetoporus splendens Mycetoporus splendidus Lordithon thoracicus

Ns 8

NI 44

Ns 4

Nl 252 N~ 22

Ns 7 Ns 4

Nt 21

Ns 10

Myllaena brevicornis (33) Leptusafumida Ni 11 NI 51

Ns 7 Ns 15

(34) (35)

N1 103

Ns 15

Othius myrmecophilus (17) Othius punctulatus

Nl 14

Aleocharinae

Lathrobium geminum Staphylininae (16) Othius angustus

Lordithon trinotatus Bolitobius cingulatus Bolitobius inclinans Sepedophilus littoreus Tachyporus chrysomelinus Tachyporus hypnorum Tachyporus nitidulus Tachyporus pusillus Tachinus bipustulatus Tachinus elongatus Tachinus laticollis Tachinus pallipes Tachinus proximus Tachinus rufipennis Tachinus signatus Tachinus subterraneus

N I 54

(36) (37)

N s 12 (38)

N t 29

Ns 6

(39)

NI 21

Ns I

(40)

N I 37 NI 11

Ns 1 Ns 5

(41) (42) (43)

NI 18 N1 34

Ns 5 Ns 7

(44) (45) (46)

N 1 29 NI 10

Ns 13 Ns 2

(47) (48)

N I 10

Ns 2

NI 22

Ns 13

N I 19

Ns 11

Leptusa pulchella Leptusa ruficollis Callicerus rigidicornis Aloconota gregaria Amischa cavifrons Sipalia circellaris Liogluta nitidiuscula Atheta arctica Atheta brunneipennis Atheta crassicornis Atheta elongatula A theta fungi Atheta hypnorum Atheta indubia Atheta pilicornis Atheta sodalis Atheta triangulum Atheta trinotata Drusilla canaliculata llyobates nigricollis Ocaleapicata Mniusa incrassata Oxypoda annularis Oxypoda elongatula Oxypoda opaca Oxypoda soror Oxypoda spectabilis Oxypoda tirolensis Oxypoda umbrata Oxypoda vittata Crataraea suturalis Aleochara brevipennis

NI

15

Ns 4

N I

74

N s 15

N I

NI 17 202

Ns 5 N s 20

N1 10

Ns 3

NI 21

Ns 5

Nl 538

Ns 21

N l 30 Nx 49

Ns 9 Ns 7

N I 138

Ns 6

Nt 195 NI 13 N l 28

Ns 14 Ns 11 Ns 11

N i 13

Ns 4

NI 40

Ns 7

Total species = 119 Species used for ordination analysis = 48 Nomenclature as Kloet and Hincks (1977). (1) to (48), species of which 10 or more individuals were collected, used in the ordination analysis; NI, no. of individuals collected; Ns, no. of sites recorded in for the species (1) to (48).