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View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by UC Research Repository Beetle diversity in forest and pastoral areas, Whangamata, Coromandel Peninsula John A. McLean1 and Diane C. Jones2 1Department of Forest Sciences, Faculty of Forestry, The University of British Columbia, 3034-2424 Main Mall, Vancouver, B.C., Canada 2Entomologist – Diagnostics, Forest Biosecurity and Protection, Ensis – the joint forces of CSIRO and Scion, PB 3020, Rotorua, New Zealand Corresponding author’s email: [email protected] (Received 1 January 2007, revised and accepted 18 January 2007) Abstract Malaise traps were set out for four weeks in December 1997 to compare the beetle populations in kanuka bush, fern bush, a 25 year old mature radiata pine stand, a 6 year old radiata pine plantation, nearby hayfi elds, grassed foreshore areas and on coastal sand dunes. Greater numbers of beetle species were collected at the forested sites than at the pastoral, urban and sand dune sites. Th e greatest number of beetle species was collected in the mature radiata pine stand, which had a well developed understorey of shade tolerant native shrub species. Th e beetle faunas at forested locations had higher degrees of endemism. Habitats maintained by constant human activity had more adventive species. Th e most common species in the grassland habitats were the lucerne weevil Sitona discoideus and the click beetle Conoderus exsul, both adventive species. Th e more numerous species in the forested habitats included the bark mould beetle Salpingus bilunatus, the elaterid Panspoeus guttatus and the fungus weevil Liromus pardalis, all native species. Keywords: beetle diversity - malaise trapping - native bush - sand dunes - grasslands - pine plantations. Introduction Recent studies of the perceptions of local perception of naturalness represent residents and visitors to the Whangamata the biological realities of the plant and area, Coromandel Peninsula, of the animal species that currently inhabit this naturalness of local landscapes showed anthropogenically modifi ed landscape? that areas of native forest and beach areas Early settler records from the 18th (without houses) were deemed more century record that a tall native tree natural than modifi ed landscapes such forest once extended to the coastline in as fi elds, plantations, residential areas this part of the Coromandel Peninsula. and urban shopping areas (Fairweather Kauri (Agathis australis) dominated the & Swaffield 1999). How does this hills, whereas coastal swampy areas were New Zealand Natural Sciences (2006) 31: 25-42 26 New Zealand Natural Sciences 31 (2006) dominated by kahikatea (Dacrycarpus well represented across all trophic levels. dacrydioides). After waves of colonisation In New Zealand there are at least 5235 by Polynesians around 600 years BP and native species of beetles in 82 families as Europeans 200 years BP, the land showed assessed by Klimaszewski (1997), plus an the eff ects of major resource extraction, additional 354 introduced species. especially of timber and kauri gum. Adams (1883) reported that the area was Methods the most ruined and disfi gured part of New Zealand at that time. Against this Pairs of standard Malaise traps (Townes background, European settlers set about 1972), with 70% isopropyl alcohol establishing an agricultural economy in the collecting jars, were set out for based on cattle and sheep farming at the one month on 5 December 1997 at beginning of the 20th century. Th e trials each of eight collecting sites in the and tribulations of this period are well Whangamata area (Figure 1). Traps reported by Williamson (1988). Forests were oriented with the collecting jars of exotic pine species were planted and towards the north. Trapping for four the mosaic seen today is a refl ection of weeks in December was recommended by those species that established satisfactorily Hutcheson & Kimberley (1999) after an to form present day plantations. Th e earlier intensive season-long assessment of area around Whangamata consists of Malaise trapping for beetles (Hutcheson protected shorelines with extensive 1990) showed that collections during sand dunes behind beaches exposed to this period gave the best discrimination the Pacifi c Ocean and an urban centre among habitats. that serves a small resident population To defi ne the composition of vegetation of 5,000 that swells to 40,000 during around each trapping location, 500 m2 summer. Farmers maintain pastoral plots were set up in collaboration with activities on the coastal plains and in C. E. Ecroyd (Curator, National Forestry the major valleys. Radiata pine (Pinus Herbarium, Scion, PB 3020, Rotorua, radiata) plantations have been established New Zealand) following the procedures on the inland hills and recolonising native of Allen and McLennan (1983) as bush has been retained on private land modifi ed with respect to cover scores by and in places such as the Wentworth Leathwick (1987). A full species list of Valley Reserve. plants for each area is available from the Th e objectives of the present study authors on request. were to evaluate diversity and degree of Trapping sites endemism of beetles (Coleoptera) in a range of habitats on the sand dunes of Site 1: The Wharekawa Harbour sand Wharekawa and the Otahu River estuary dunes (Figure 1), the grass walkways between beachfront properties at Whangamata, The dunes have been planted with pastures, a young radiata pine plantation, radiata pine and maritime pine (Pinus a mature radiata pine stand, a fern- pinaster). The two Malaise traps were dominated bush area and a kanuka- set up 50 m apart in leeward hollows dominated bush reserve. Th e Coleoptera of the front dunes, and were partially is the largest of the insect orders and is protected from on-shore winds by the J.A. MCLEAN & D.C. JONES: Beetle diversity in the Whangamata area 27 pines. The major ground cover was arundinacea), knotty clubrush, Indian harestail (Lagurus ovata). Other species doad (Cynodon dactylon) and kikuyu grass present were pohuhue (Muehlenbeckia (Pennisteum clandestinum). Trap 2B was complexa), spinifex (Spinifex sericeus), set out in an area that was dominated by knotty clubrush (Isolepis nodosa) and the spinifex, catsear (Hypocheris radicata), sand dune moss (Thuidium furfurosum). knotty clubrush and lupin (Lupinus arboreus). Sand coprosma (Coproma Site 2: The Otahu River sand dunes acerosa), pohuhue and shore bindweed Several species have been planted (Calystegia soldanella) trailed through the throughout this heavily used area in an areas around both traps. effort to stabilize the sand dunes. The Site 3: The grassed walkways that provide dunes provide access to the ocean beach public access to the main Whangamata as well as protected waters at the mouth of beach from Pohutukawa Drive the Otahu River. Trap 2A was set out in a well grassed area with a small pohutukawa These sites were very dry in the middle of (Metrosideros excelsa) to the south. The summer. Traps 3A and 3B were anchored major grasses present were cocksfoot on the southern side of two walkways. (Dactylis glomerata), tall fescue (Festuca Kikuyu grass was the dominant species Figure 1. Locations of the eight collecting sites in the Whangamata area where pairs of Malaise traps were set out in December 1997. Note the disjunction between 41” and 50” parallels. The town of Whangamata is located at 37° 13’ 40” S, 175° 52’ 50” E. 28 New Zealand Natural Sciences 31 (2006) at each site and each trap had a coast through to the forest floor to enable Banksia tree (Banksia integrifolia) close by. shade tolerant native species to survive. Bare ground made up 30% and 20% of We tabulated 21 native species around the area at Traps 3A and 3B, respectively. trap 6A and 28 species around trap Some paspalum (Paspalum dilatatum) 6B. Among these were mapou (Myrsine grew close to the fences, but did not australis), karamu (Coprosma robusta), spread over the walkways. mamaku (Cyathea medullaris), rangiora (Brachyglottis repanda), silver fern, fi ve Site 4: Pastures in the Wentworth Valley fi nger (Pseudopanax arboreus), dwarf ti locked up for hay production (Cordyline banksii) and bracken. Trap 4A was set out in a paddock on the Site 7: Fern Bush south side of Wentworth Valley Road, whereas Trap 4B was in a paddock on the Beyond the kanuka (Kunzea ericoides) north side of the road. The Wentworth and mamaku edge of this fern-rich site River ran through the north paddock. was an emergent vegetation of rewarewa The main grasses around Trap 4A were (Knightia excelsa) and towai (Weinmannia sweet vernal (Anthoxanthum odoratum) silvicola). Silver fern was the dominant and brown top (Agrostis capillaris). Sweet pteridophyte. Rangiora, kawakawa vernal was also the major pasture grass (Macropiper excelsum), fi ve fi nger and around Trap 4B with Yorkshire fog (Holcus mahoe (Melicytis ramifl orus), were present lanatus), lotus (Lotus pedunculatus), red in height tier 4 (2-5 m). We tabulated 18 clover (Trifolium pretense), and paspalum and 29 plant species around traps 7A and species also present. 7B, respectively. Several epiphytes were also recorded. Traps were located at least Site 5: A 6 year old second growth radiata 10 m within this bush remnant. pine plantation on an east facing slope 25 m below the Pa Road Lookout Site 8: The kanuka-dominated native bush near the start of the Wentworth Purple pampus grass (Cortaderia jubata) Valley Reserve walking track was clearly visible at the edge of the plantation and also scattered through- Trap 8A was set out in an area rich in out the stand along with tutu (Coriaria silver fern, mapou and nikau (Rhopalostylis arborea). Bare soil made up 40% and sapida). Wheki (Dicksonia squarossa) bracken (Pteridium esculentum), was was also common in the understorey. widely distributed at low density. Silver We recorded 30 species at this location fern (Cyathea dealbata), was moderately including four epiphytes.