The Macrofungal Community and Fire in a Mountain Ash Forest in Southern Australia
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Fungal Diversity The macrofungal community and fire in a Mountain Ash forest in southern Australia Sapphire J.M. McMullan-Fisherl,z*, Tom W. May3 and Phil J. Keanel 'School of Botany, La Trobe University, Bundoora, Victoria 3084, Australia 2Current address: University of Tasmania, GPO Box 252-78, Hobart, Tasmania 7001, Australia 3Royal Botanic Gardens Melbourne, Birdwood Ave, South Yarra, Victoria 3141, Australia McMullan-Fisher, S.J.M., May, T.W. and Keane, P.J. (2002). The macrofungal community and fire in a Mountain Ash forest in southern Australia. In: Fungal Succession (eds. K.D. Hyde and E.B.G. Jones). Fungal Diversity 10: 57-76. Changes in the occurrence of macrofungi with time following forestry activities and fire were studied at 14 sites in Mountain Ash (Eucalyptus regnans) dominated forests, in the Eastern Central Highlands, Victoria, Australia. Forests of 0-57 years after fire were used to compare macrofungal communities. Pattern analysis through classification and ordination showed that there was a distinct change in the macrofungal community over time since disturbance. Three phases were apparent in the process of recolonisation after fire: (1) immediate post-fire (0• year), (2) an intermediate phase (2- and 4-year-old), and (3) a mature phase (7-year-old and older). The macrofungi evident in the Mountain Ash forest during the first year after fire were the most distinctive. The change in the suite of macrofungi closely reflected the changes in macro fungal substrates in the forests of different ages. Macrofungi found to be specific to certain stages of regeneration after fire will provide a subset of indicator taxa suitable for use in further surveys. Key words: classification, Eucalyptus regnans, forestry, indicator taxa, macrofungi, ordination, recolonisation, Victoria. Introduction Macrofungi, such as agarics, coral fungi, polypores and cup- and disc• fungi, play important roles in the ecology of Eucalyptus forest communities, particularly as saprotrophs and through mycorrhizal partnerships (May and Simpson, 1997). Fire is one of the driving forces shaping the Australian landscape, particularly eucalypt forests. It is well-known that some macrofungi are stimulated to produce fruit bodies after fire (Petersen, 1970; Cribb and Cribb, 1971; Carpenter and Trappe, 1985; Carpenter et al., 1987; Watling, 1988; Duchesne and Weber, 1993), and some studies have been carried out in Northern Hemisphere forests to investigate the effect of fire on the macrofungal community (Watling 1988; Visser 1995; Visser and Parkinson, * Corresponding author: Sapphire J.M. McMullan-Fisher; email: [email protected] 57 1999). There has however, been little research on the effect of fire on the macrofungal community in Australian forests. Gill and Ashton (1971) listed macrofungi as part of a study of eucalypt forests on different soils; fire was part of the site history but its direct effects were not considered. Warcup (1990) demonstrated a succession of epigeal and hypogeallarger ascomycetes in the first three years after fire in plantations of Eucalyptus maculata in South Australia. The effect of fire on the production of fruit bodies of hypogeal fungi, which provide food for mycophagous Australian mammals, has been investigated by a number of authors (Taylor, 1991; Claridge, 1992; Johnson, 1997). The analysis of macrofungal communities in different continents has mainly been carried out using visual examination of tables of species of fungi from different sites (Winterhoff, 1992). Multivariate analyses are often used for plant community data (Whittaker, 1978), but Arnolds (1992) highlights the lack of application of such techniques to the study of macrofungal communities. Villeneuve et al. (1991a,b) used pattern analysis to successfully elucidate fungal communities within Canadian forests. For Tasmanian wet forests, multivariate analysis of replicated plot-based data was used by Packham et al. (2002) in their study of the macrofungi of old growth forests in comparison to silvicultural regrowth. For saprotrophic fungi on logs of Mountain Beech (Nothofagus solandri var. cliffortioides) in a New Zealand temperate forest, AlIen et al. (2000) used multivariate analysis to compare the community of fungi on logs differing in decay stage and other characteristics. The present study uses multivariate analysis of plot-based samples to investigate the effects of disturbance by fire on the macrofungi in forest dominated by Mountain Ash (Eucalyptus regnans) in the Eastern Central Highlands, Victoria. The study focuses on the relationships between the diversity of macrofungi, plants and substrates in forests of different age since fire. Materials and methods Study area The 14 study sites were located in the Eastern Central Highlands, Victoria, Australia. All sites were within 30 km of each other and were located in the Loch Valley, Latrobe River and Powelltown areas. Sites were all on well-drained granitic soils as part of the Kirchube1 land system. The forests were subject to management and logging operations under the control of the Victorian Department of Natural Resources and Environment. Sites were located in E. regnans forest of different ages since disturbance (Table 1). 58 III Fungal Diversity Table 1. Site and disturbance details. Year of fire Years since fire Site Geographic coordinates Type of disturbance* 1996 0 AD96 37°52'45"S,145°53'23"E RB CC96 37°53'09"S, l45°57'55"E RB L096 37°47'37"S, 146°00'53"E RB 1994 2 AD94 37°52'46"S,145°52'03"E RB L094 37°46'42"S,145°56'40"E RB 1992 4 L092 37°47'47"S,145°58'OO"E RB B092 37°45'47"S,145°56'29"E RB 1989 7 CC89 37°53'50"S,145°57'45"E RB 1983 13 L083 37°45'31"S,145°59'09"E RB PT83 37°52'57"S, 145°48'OTE WS BU83 37°52'45"S,145°48'16"E WS 1939 57 AD39 37°52'45"S,145°53'09"E W CC39 37°53'25"S,145°57'41"E W PT39 37°53'47"S,145°58'4TE W * RB = regeneration burnt after logging; W = burnt by wildfire; WS = burnt by wildfire and salvage logged. Macrofungal identification Macrofungi were those species with readily visible fruit bodies (generally larger than 1 mm). Where possible macrofungi were identified to species, either to named species, or sometimes using informal names for distinct but undescribed species as applied at the National Herbarium of Victoria (MEL). Most identification was carried out in the field, but in some cases specimens were examined microscopically to confirm identification, using standard methods (Singer, 1986). Fungal names follow the Catalogue and Bibliography of Australian Macrofungi (May and Wood, 1997; May et al., 2002). Macrofungi that were unable to be identified to species were grouped into "field taxa", which were macroscopically similar fungi that would mostly have belonged to a single genus. Some field taxa, which varied very little in morphology, may represent a single undescribed species. Other field taxa, however, had variable morphology within a single genus and so probably represent a group of species. If material suitable for a herbarium specimen was present, a voucher was collected and lodged at MEL. Some field taxa observed were not collected due to time and processing constraints and a lack of suitable speCImens. Macrofungalsurvey At each site, ten 10 m2 (1 x 10 m) strip plots were established at random positions and orientation within a 2 ha area. A priori decisions were made not to place plots on tracks or log landings (which are often compacted) or along 59 Table 2. Substrate groups. Substrate group Description Burnt soil Burnt soil red and black coloured depending on the temperature of the fire, black burnt soil contained charcoal pieces. Burnt wood Wood, including stumps which has been partially burnt or entirely charred. Bare soil Soil, which has not obviously been burnt, and is not covered by moss or litter. Litter Wood that is smaller than 1 cm in diam. and dead leaves covering the ground. Bark Eucalyptus regnans bark which has fallen off the trees. Small wood Dead trees and branches from 1-5 cm in diam. Large wood Dead wood, including stumps and moss-covered wood, which was greater than 5 cm in diam. Wire grass Dead and living Tetrarrhena juncea. Live regnans Live Eucalyptus regnans buttresses, surveyed to a height of 2 m. Moss The total covering of moss on plants, wood and the ground. Dung Herbivore dung. creek lines (where different vegetation may be present). Strip plots were used to prevent disturbance due to the surveying (e.g. trampling) and to ensure that fruit bodies were not overlooked in the dense undergrowth. Every visible surface in the strip plots to a height of 2 m was surveyed for the presence of fruit bodies. Vegetation and fallen timber was disturbed as little as possible during each survey. Presence of each macrofungal taxon on each strip plot was recorded, along with the range of its substrates. Because of the irregular distribution of fruit bodies, the macro fungi found outside the plots but within the 2 ha area (within the same habitat) were also recorded, along with their substrates. Surveys of the strip-plots and the 2 ha sites were undertaken in April, June, July and October 1996 and in January 1997. In addition, short (15 minute) surveys at all sites were carried out monthly from April 1996 to January 1997 inclusive, by walking around the same 2 ha sites in which the plots were located (excluding the plots themselves) searching for macrofungi. The 2- and 4- year-old sites were surveyed from July 1996 onwards. Plant and substrate surveys In January 1997, at each site, each of the ten strip plots used for the macrofungal survey were extended to 300 m2 (3 x 10 m) and the cover of vascular plants, bryophytes and substrates was recorded.