A report on the macrofungi observed in an aggregated retention coupe at the Warra LTER

Macrofungal biodiversity in an aggregated retention coupe at the Warra LTER

Genevieve M. Gates¹ and David A. Ratkowsky^1,2

¹School of Plant Science, University of Tasmania, Private Bag 55, Hobart 7001

²School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart 7001

Abstract

The macrofungi of an aggregated retention coupe (WR001E) at the Warra long-term ecological research site (LTER) were documented at approximately fortnightly intervals over a period of 16 months between February 2005 and June 2006. An unharvested mature coupe of the same forest type (WR008J) was used for comparison. In the islands of WR001E, 169 macrofungal species were recorded compared to 125 species in the harvested areas of the same coupe and 288 species in the mature forest. Although 130 species were shared between coupes WR001E and WR008J, there were 158 species unique to WR008J and 99 species unique to 1E. Seasonal effects were clearly observed in all sampling units, with many more species appearing in the autumn and winter months than in spring and summer. Most of the species known or believed to be mycorrhizal were unique to the mature or unharvested forest. The regenerating units were a source of many saprotrophic fungi and also contained many species that are either known from the Northern Hemisphere but not observed in mature Tasmanian forests, or are characteristically opportunistic, appearing after disturbance but not generally seen in forests that have progressed beyond the earliest stage of regeneration. In addition, an escaped regeneration burn in forest at the junction of Bennetts and Arve Roads provided a sampling unit in which to observe the earliest succession of macrofungi after wildfire. This gave a time line of zero to 3.2 years with which to document the succession of macrofungi of the lowland wet eucalypt forest in southern Tasmania after disturbance and fire. Substantial differences were observed between the mycota in the earliest stage of regeneration and in the subsequent stages of regeneration. The results suggest that the retained islands of aggregated retention are a good source of macrofungal biodiversity, but the size of these islands may need to be increased to counteract the drying effect resulting from their proximity to the harvested areas.

Introduction

For background material and references that document the role of fungi in the forest ecosystem, the reader is referred to our earlier publication (Gates et al. 2005). Mycorrhizal fungi are especially important. The earlier study provided an inventory of macrofungal species for lowland wet eucalypt forest at the Warra long-term ecological research site (LTER) and also identified differences between the mycota of two adjacent coupes that were subjected to different silvicultural treatments. In that study, a clearfelled, burnt and sown (CBS) coupe (WR008H) was compared to an unharvested mature wet eucalypt forest (WR008J), the study commencing 26 months after sowing and continuing for 12 months. The mature forest is a stage in the succession towards rainforest. Differences in the mycota between those two coupes were found for species richness, assemblage composition, and substrate associations (Gates et al. 2005). At the end of the field work for that study (29 June 2004), three years and two months had elapsed after burning and sowing, which was insufficient time for the majority of the symbiotic fungal species to begin fruiting. Only 11 ectomycorrhizal species were recorded in the CBS coupe, compared with 65 in the unharvested coupe.

The aim of the present study was to extend the survey of the macrofungi to another silvicultural treatment, one to which the “aggregated retention” treatment had been applied. Aggregated retention is an experimental silvicultural treatment seen as a potential replacement for CBS in lowland wet eucalypt forest. For a discussion of the pros and cons of aggregated retention compared with the more traditional CBS silviculture, see Hickey et al. (2001). Of the two coupes at Warra having this silvicultural regime, the coupe known as WR001E was deemed to be the more suitable for assessing mycota, because of the state of its site preparation. The coupe consisted of unlogged islands separated by harvested and burnt areas that were not resown (see Figure 1). Burning was applied as a low intensity fire, rather than as a hot fire as used in CBS. Because a low intensity burn misses some of the area intended to be burnt, a mosaic resulted in which part of the harvested area was unburnt, while the remainder was burnt to varying degrees. The interior of the retained islands used in the survey escaped burning, but some parts of the periphery were singed or scorched. The mycota of the retained islands and of the harvested areas may be compared collectively or separately to the mycota of an unharvested control. The mature coupe WR008J was used for the control, as in Gates et al. 2005. Similarly, the harvested areas of the aggregated retention can be compared to the regenerating CBS plot of the earlier study, although one needs to be mindful of the difference in the time since burning when making such comparisons.

Methods

Sites

The two coupes used were located juxtaposed at the Warra LTER site, having an approximate latitude of 43º06´S and longitude of 146º42´E. Coupe WR008J (hereafter generally referred to as “mature forest” or abbreviated as “8J”) had no previous history of logging. Coupe WR001E (hereafter generally referred to as “aggregated retention” or abbreviated as “1E”) had ca. 70% of its area harvested, with the remaining 30% retained in eight islands, the size of each of which differed and ranged between 0.4-0.73 ha. Generally, in aggregated retention as practiced in North America, 15-40% of the trees in the coupe are retained in unharvested islands whose size falls in the range 0.1-1.0 ha (Franklin et al., 2001). Harvesting of this coupe began on 26 March 2003, was completed on 5 August 2003 and a low intensity regeneration burn was conducted on 20 April 2004. No sowing of seed followed. The fire history of the lowland wet eucalypt forest at Warra was given by Hickey et al. (1999) and the vegetation of the silvicultural systems trial area was described by Neyland (2001). The latter paper did not describe the floristics of individual coupes, but 8J can be classified as a wet sclerophyll forest with Eucalyptus obliqua L’Hérit. as the dominant eucalypt. The understorey is of the “G” type, containing large amounts of Bauera rubioides Andrews, Gahnia grandis (Labill.) S.T. Blake and Melaleuca squarrosa Donn ex Smith, but lacking Nothofagus cunninghamii (Hook.) Oerst. and other rainforest elements.

The lack of the fire-sensitive rainforest elements and the multi-aged nature of the eucalypts imply that the last wildfire was not stand-replacing and was about 70 years ago. Before aggregated retention was applied, coupe 1E, the western boundary of which adjoins the mature forest, was the same type of wet sclerophyll forest and also had a “G” type understorey. Both coupes were on a gentle to moderate south-facing slope, the rock type being Quaternary dolerite talus overlying Permian sediments, with water drainage from north to south.

Survey methods

Three of the seven islands, labelled W (West), C (Centre) and E (East) in Figure 1, were chosen for use in the survey, as some tracks had already been cut for use in other research projects in these islands. Additional tracks were subsequently cut within these islands to give a total transect length of ca. 400m. This corresponds approximately to the transect distance in the harvested areas, when the individual distances are added together. In the mature forest coupe, the same track was used as that of the previous study (see Gates et al. 2005), but instead of using the full 1300m transect length, only the first 400m of the track was used for comparability to the sampling effort within the islands of 1E and to the sampling effort in the harvested areas of that coupe.

Both coupes were surveyed on the same day at approximately fortnightly intervals during 35 visits between 8 February 2005 and 16 June 2006. Species of macrofungi seen from the track were recorded, but no diversions were made from the track. In the aggregated retention, there were seven distinct sampling areas, in each of which a separate list of fungi was made. The three unharvested islands comprised the “islands” sampling unit and the four cleared areas separating the islands from each other and from the car park comprised the “harvested areas” sampling unit. All species of macrofungi found in the seven areas were recorded as formal names or as “tag” names (see next section), along with the substrate on which they appeared. Numbers of fruiting bodies were not counted, only presence/absence noted. In the harvested areas of 1E, in addition to recording the substrate, a note was made for each species of whether the substrate had been burned or escaped burning in the low intensity burn applied to this coupe. Therefore, the following categories resulted: wood burnt, wood unburnt, soil burnt, soil unburnt, litter burnt, litter unburnt, and dung. It was originally planned to have two categories of burn intensity for soil, one reflecting the hot, calcining burn that was sporadically present in portions of the regeneration area, and the other for the areas that did not receive this hotter burn. However, no fungi were seen in the barren, calcined areas, so this category never came into use.

All collections were supported with descriptions, drawings and photographs of macroscopic and microscopic features. Material was collected wherever possible to be deposited in the Tasmanian Herbarium (HO) as voucher material for this study.

Species names

As the taxonomy of the Australian mycota remains poorly known, with the majority of species still to be validly named, we used a mixture of validly described species and readily recognised entities to which we have given “tag” names. Species new to the authors were macroscopically and microscopically described. Names of species of the Basidiomycota that have been validly described were taken from May and Wood (1997), May et al. (2003) or from the interactive, updated list of fungi on the Royal Botanic Gardens Melbourne website (www.rbg.vic.gov.au). As no Australian catalogue of Ascomycota exists at the present time, the names used in this paper for those species are based on those in current use by Australian authors or can be searched on websites such as the Index Fungorum (www.indexfungorum.org/Names/Names.asp) or Landcare Research, New Zealand (nzfungi.landcareresearch.co.nz/html/mycology.asp).

Statistical methods

As both coupes were sampled at each visit, paired-sample statistical tests such as the t-test and its nonparametric equivalent, the Wilcoxon signed-rank test, were employed to test null hypotheses of no differences in species richness between the two coupes, or between parts of those coupes, such as (i) islands of 1E vs. mature forest (8J), or (ii) harvested areas of 1E vs. islands of 1E, etc. Contingency table analysis was used to test for between-coupe differences, or differences between parts of those coupes, such as harvested areas vs. islands, in the proportion of species associated with particular substrates.

An estimate of the potentially detectable species richness in each coupe, or sampling units of a coupe, was made by fitting a parametric model containing an asymptote to mean values of randomised species accumulation data generated by the package EstimateS (Colwell, 2005), using the default value of 50 randomisations of sample order. The choice of model was the extended Langmuir model (see Sibbesen 1981):

R = A/(1+B S^-C) (Equation 1)

where S = number of samples, R = species richness, and A, B and C are three parameters to be estimated. This model was successfully employed in our previous study (Gates et al. 2005), and was fitted using nonlinear regression (PROC NLIN of SAS, SAS Institute, Version 8.2).

Non-metric multidimensional scaling (nMDS) was used to display multivariate patterns among samples visually, employing the program PRIMER 5 (2001). To eliminate the diluting effect of low numbers of observations, only 225 species (of the total of 387 species in the full data set) that were observed more than once were used. In addition, to reduce the effect of distortion attributable to low numbers, only those visits to the three sampling units (viz. 8J, the harvested areas of 1E, and the islands of 1E) in which at least two species were recorded were used. The similarity matrices among the visits, based upon the presence or absence of the species recorded at each visit, were defined using the Bray-Curtis measure without data transformation. The resulting ordination diagrams in two dimensions were labelled to display differences due to seasons as well as to silvicultural treatments.

Results

Species identification

Of the 387 species recorded during the survey, 178 species (46%) are formally described, with the remainder bearing tag names only. All species found are listed in alphabetical order in Appendix 1, without regard to their taxonomic position, the latter being in a constant state of flux. The coupe, the habitat, the substrate, the life mode and the preferred seasons in which they were recorded are indicated.

Species richness and frequency distributions

As 35 visits were made to each of the two coupes, the maximum number of unduplicated records that is possible for any species is 35 for each coupe for a total of 70 “occasions”. However, in the aggregated retention coupe, separate listings were made for each of the component parts of the two sampling units, being the three islands and the four harvested regions between the islands and/or the carpark and the islands. For comparing species richness, tabulations of unduplicated records were used, i.e. species appearing in more than one component part of a sampling unit were counted only once. Only two species were recorded on more than half of these 70 occasions, 9 species were found during more than one-third of the occasions, and 24 species were found during more than one-quarter of the occasions (Table 1 and Figure 2). Of the 387 species recorded, 302 (78%) were observed on 10% of occasions or fewer, with 162 (41.9%) recorded once only. In the mature forest (8J), 5 species were found on more than half of the 35 visits, with 23 species counted in 10 or more visits.

The aggregated retention coupe consists of two habitats, the retained islands and the partially burnt harvested areas. This division must be borne in mind when comparisons between coupes are being made. From Table 1, it can be seen that seven species were found on more than half of the 35 visits to 1E overall, with 29 species counted in at least 10 visits. However, the columns of Table 1 pertaining to the islands of 1E and the harvested areas of 1E separately show that no species were observed in the islands on more than half of the visits, whereas six species were observed in the harvested areas on at least half the visits. In at least 10 visits, eight species were observed in the islands and 17 species recorded in the harvested areas.

Table 1: The 65 most frequently observed species in the present survey.

Species binomial	Number of records	8J Total	1E Total	1E Islands	1E Harvested areas
Polyporus melanopus	38	22	16	12	7
Stereum hirsutum	38	20	18	15	13
Collybia eucalyptorum	33	21	12	12	4
Mycena cystidiosa	27	15	12	12	6
Boletellus obscurecoccineus	25	12	13	13	0
Calocera guepinioides	25	14	11	6	7
Discinella terrestris	25	18	7	6	2
Laccaria spp.	25	10	15	13	12
Lactarius clarkeae	24	16	8	8	0
Loreleia marchantiae	23	0	23	0	23
Melanotus hepatochrous	23	0	23	4	23
Ascocoryne sarcoides	22	18	4	3	3
Gymnopilus allantopus	22	10	12	8	9
Psilocybe formosa	21	9	12	5	8
Pycnoporus coccineus	21	0	21	0	21
Rhodocollybia butyracea	21	5	16	13	6
Galerina nana	20	0	20	0	20
Scutellinia scutellata	20	1	19	2	18
Tremella fuciformis	20	6	14	9	8
Mycena toyerlaricola	19	11	8	8	0
Panellus stipticus	19	13	6	1	6
Galerina sp. ‘with sphaeropedunculate cheilocystidia’	18	11	7	7	0
Pholiota highlandensis	18	0	18	0	18
Scutellinia margaritacea	18	1	17	13	8
Mycena kurramulla	17	11	6	5	5
Stereum illudens	17	2	15	9	14
Marasmiellus affixus	16	11	5	5	0
Stereum ostrea	16	16	0	0	0
Mycena mulawaestris	15	8	7	4	3
Phellodon niger	15	14	1	1	0
Trametes versicolor	15	1	14	0	14
Cortinarius sp. ‘C62, varnished, golden brown with…’	14	9	5	5	0
Gymnopilus tyallus	14	5	9	7	7
Gymnopus sp. ‘brown frilly’	14	5	9	7	6
Heterotextus peziziformis	14	4	10	6	6
Hypholoma brunneum	14	7	7	2	7
Lyophyllum sp. ‘small, brown’	14	0	14	0	14
Mycena epipterygia	14	8	6	6	2
Mycena interrupta	14	9	5	5	0
Cantharellus concinnus	13	13	0	0	0
Lactarius eucalypti	13	12	1	1	0
Mycena sanguinolenta	13	3	10	5	9
Mycena viscidocruenta	13	8	5	4	1
Podoserpula pusio	13	13	0	0	0
Ryvardenia campyla	13	11	2	2	0
Cortinarius sp. ‘C48, lilac and brown, Phlegmacium’	12	5	7	7	0
Mycena sp. ‘brown striate, becoming sulcate’	12	0	12	0	12
Mycena albidofusca	12	7	5	5	1
Byssomerulius corium	11	0	11	0	11
Coprinus angulatus	11	0	11	0	11
Gymnopus sp. ‘hygrophanous reddish brown’	11	0	11	3	10
Mycena carmeliana	11	6	5	3	2
Pholiota squarrosipes	11	11	0	0	0
Postia pelliculosa	11	5	6	1	5
Aleuria aurantia	10	0	10	0	10
Bisporella sp. ‘green-yellow’	10	7	3	1	2
Clitocybula sp. ‘Notley yellow’	10	7	3	2	1
Crepidotus variabilis	10	4	6	4	2
Entoloma austroprunicolor	10	6	4	4	0
Mycena albidocapillaris	10	6	4	4	1
Pluteus sp. ‘brown velvet cap, pink stipe and gills’	10	1	9	0	9
Pluteus atromarginatus	10	4	6	1	6
Pulveroboletus ravenelii	10	6	4	4	0
Schizophyllum commune	10	0	10	0	10
Tephrocybe sp. ‘grey-brown’	10	7	3	2	1

Species richness was much higher in the mature forest (288 species in 8J from a total of 942 records and 169 species in the islands of 1E from 496 records) than in the regeneration (125 species in the harvested areas from 548 records). The mean number of species observed per visit in the mature forest was 26.8, compared to 15.7 in the harvested areas of 1E (Table 3). Tests of significance between coupe 8J and all or parts of coupe 1E produce the following results: 8J vs. 1E (total), t=0.04, df=34, P=0.968, not significant; 8J vs. 1E (islands) t=7.19, df=34, P<0.0001, highly significant; 8J vs. 1E (harvested) t=6.34, df=34, P<0.0001, highly significant. A test of the mean number of species in the harvested areas of 1E vs. that in the islands of 1E gives t=1.52, df=34, P=0.138, not significant. In all cases, the residuals were close to being normally distributed, obviating the need for use of the Wilcoxon signed-rank test.

Randomised species accumulation data are shown in Figure 3, the points on the graph having been determined as the mean of 50 random samples (with replacement) made from the 35 visits to each coupe (or part thereof) using EstimateS (Colwell 2005). The solid curves are the fitted extended Langmuir model (Equation 1), and it is clear that, in each coupe or part of the coupe, this model provides an excellent fit to the data. Predicted values of the asymptote, the parameter defining the estimated total species richness, are given in Table 4. Although the standard errors appear to be small, reflecting the excellent fit of the model to the smoothed species accumulation data, it is clear that 35 visits are far too few for any of these species richness curves to closely approach its asymptote and thereby provide an adequate prediction of the potential species richness in each coupe or portion thereof. The range of the ratio of observed to estimated species richness was 46-58%.

Table 3: Fungal species numbers observed at each visit to coupe 8J and 1E, with the species numbers in the aggregated retention expressed as the total observed in the coupe and in the harvested areas and islands separately.

Date	8J	1E (Islands)	1E (Harvested areas)	1E (Total)
8-Feb-05	18	1	7	8
22-Feb-05	30	1	6	7
8-Mar-05	20	4	4	7
21-Mar-05	25	7	8	15
31-Mar-05	14	4	6	10
13-Apr-05	42	2	18	20
26-Apr-05	52	26	24	46
10-May-05	47	14	13	26
24-May-05	30	17	16	31
7-Jun-05	48	28	36	56
21-Jun-05	47	46	42	73
12-Jul-05	38	19	31	45
28-Jul-05	18	25	21	39
9-Aug-05	13	10	8	18
23-Aug-05	6	16	24	36
6-Sep-05	22	9	12	20
20-Sep-05	21	6	8	13
4-Oct-05	12	7	19	22
18-Oct-05	14	5	13	18
1-Nov-05	8	4	3	6
15-Nov-05	13	14	8	20
29-Nov-05	10	4	4	7
13-Dec-05	18	9	15	22
27-Dec-05	21	17	8	23
12-Jan-06	11	7	0	7
3-Feb-06	15	3	1	4
21-Feb-06	9	0	4	4
7-Mar-06	19	3	6	9
21-Mar-06	17	3	6	9
6-Apr-06	26	14	10	21
20-Apr-06	38	27	28	50
2-May-06	52	32	29	57
20-May-06	59	43	48	75
3-Jun-06	67	40	32	61
16-Jun-06	42	29	30	54
Totals	942	496	548	939
Means	26.9	14.2	15.7	26.8

t-test, 8J vs. 1E (Total): t=0.04, df=34, P=0.968^ns

t-test, 8J vs. 1E (Islands): t=7.19, df=34, P<0.0001

t-test, 8J vs. 1E (Harvested areas): t=6.34, df=34, P<0.0001

t-test, 1E (Harvested areas) vs. 1E (Islands): t=1.52, df=34, P=0.138^ns

Figure 3. Species accumulation curves for different parts of the survey. Data points form the randomised species accumulation curves, and were obtained from 50 random permutations of the 35 visits. Solid curves are from the extended Langmuir model fitted to each subset of data separately.

In the macrofungi, there is a strong correlation between their main life mode, i.e. whether a species is mycorrhizal, saprotrophic or parasitic, and the substrate on which it is found. Mycorrhizal species are predominantly found on soil, whereas saprotrophic and parasitic species are mostly on dead, dying and decaying wood or litter, rarely on soil. When classified with respect to two factors, life mode and by coupe (Table 8), using all of the 387 species of this study, the 2 x 3 contingency table formed from the subtotals, excluding the two species of uncertain life mode, is highly significant (χ² = 12.5, 2 df, P=0.0019). However, a more enlightening way to view and interpret the results is to classify them by life mode and by treatment, i.e. whether the species was exclusive to the regenerating areas of the aggregated retention coupe, or exclusive to the uncut forest (8J or islands of 1E), or was found jointly in both. This classification is shown in Table 9, in which the proportions of mycorrhizal and decomposer species in the various sampling units are highly significantly different (χ² = 61.5, 2 df, P<0.0001). The difference in proportions reflects the dominance of the unique mycorrhizal species in the uncut forest (124 species, 93.2%), with only six mycorrhizal species unique to the regeneration and three species jointly found in both treatments. In contrast, a smaller proportion (54.0%) of the saprotrophic or parasitic species were unique to the uncut forest (Table 9).

Table 8. Numbers (and percentages of row totals) of species of macrofungi observed in the present study classified by their life mode and by coupe.

Life mode:	No. of species exclusive to the aggregated retention coupe 1E	No. of species exclusive to the mature forest 8J	No. of species found in both coupes	Total number of species
Mycorrhizal species:	26 (19.6%)	70 (52.6)	37 (27.8)	133
Decomposer species:	73 (29.0)	86 (34.1)	93 (36.9)	252
Species of uncertain life mode	0	2	0	2
Total no. of species	99	158	130	387

Table 9. Numbers (and percentages of row totals) of species classified according to treatment.

Life mode:	In harvested areas of 1E only	In uncut forest only (8J or islands of 1E)	In both harvested and uncut areas	Total number of species
Mycorrhizal species:	6 (4.5%)	124 (93.2)	3 (2.3)	133
Decomposer species:	56 (22.2)	136 (54.0)	60 (23.8)	252
Species of uncertain life mode	0	2	0	2
Total no. of species	62	262	63	387

Discussion

Species identification

A high proportion of the species identified in this survey (209 out of 387, or 54%) is undescribed. This is typical of macrofungal studies, as only a small fraction of the Australian mycota has been named to species level. We noted in our earlier study (Gates et al. 2005) that the prevalence of so many undescribed species in this type of study was common, even in countries where the mycota is relatively well known (e.g., see Straatsma et al. 2001). We also noted there that high proportions of undescribed species were reported in Tasmanian studies of beetles, and that rarity of species was typical in forest studies of lichens. The large number of rarely observed, undescribed species suggests the need for further studies of these taxa in forest ecosystems. Progress in naming species is inevitably slow, with little effort and funding being directed into the taxonomy of fungi, a situation lamented recently by Korf (2005). The present authors have made some progress in identifying a few species previously reported (Gates et al. 2005) as tag names, but for which it now appears that there are published names. These include: Jelly fungus sp. ‘grey tapioca’ = Sirobasidium brefeldianum; Stereum sp. ‘drab’ = Stereum ochraceoflavum (Schwein.) Sacc. (syn. Stereum vellereum Berk.); Stereum sp. ‘lilac’ = Chondrostereum purpureum (Pers.) Pouzar; Tricholomataceae ‘all-grey, streaky, anastomosing’ = Trogia straminea Corner.

Species richness

The t-test (Table 3, bottom) of the difference between the mean numbers of species in the mature forest 8J and the whole of the aggregated retention coupe 1E was non-significant (P=0.968), suggesting that the two coupes are equally rich in their total macromycota. Nevertheless, when 1E was divided into its two sampling units and further t-tests were carried out with 8J, highly significant differences in species richness were obtained (Table 3, bottom). The test of harvested areas against islands found no significant difference, so that the two sampling units of 1E are about equally rich in species numbers. However, as Tables 1 and 2 demonstrate, they differ greatly in their species composition. Similar to the findings of our previous study (Gates et al. 2005), regeneration was found to support less species numbers than the mature forest (125 in the harvested areas compared to 288 in 8J and 169 in the islands). Those species that were unique to the regeneration include some that were observed frequently in the regenerating coupe of the CBS silvicultural treatment studied previously (Gates et al. 2005), such as Pycnoporus coccineus, Galerina nana, Trametes versicolor, Mycena ‘brown striate …’, Byssomerulius corium, Aleuria aurantia and Schizophyllum commune, but other species were observed in the present study that did not occur in the earlier study, e.g. Loreleia marchantiae, Pholiota highlandensis, Lyophyllum ‘small, brown’, and Coprinus angulatus. The reason for this is to be found in the different time after burning, to be discussed later in this paper.

The much smaller number of species observed in the islands of 1E compared to that in the mature forest 8J (169 vs. 288) is probably a consequence of the drying effect experienced by islands of the size 0.5-0.73 h, especially when contrasted with a closed-canopy coupe of contiguous forest. Although nominally of the same forest type as the mature forest 8J, there were discernible differences among the three islands of 1E that were studied. The greatest number of species was observed in Island “W” (99 spp.), followed by “C” (86 spp.), then by “E” (68 spp.). “W” appeared to be consistently wetter than the other islands, having a thick understorey of Bauera rubioides, with “E” being the driest, the latter also having had more encroachment from the regeneration burn than either of the other two islands, resulting in patches of Gahnia grandis being present. “C” was intermediate in dryness between “W” and “E”, with some Gahnia also present.

Differences in species richness were also observed in the four individual areas that make up the harvested portion of 1E. The species numbers were as follows: Car park to “W”, 62 spp. from 194 records; “W” to “C”, 74 spp. from 126 records; “C” to “E”, 72 spp. from 247 records; “E” to car park, 74 spp. from 257 records. Thus, although the total number of records varies greatly amongst the four units, differing by a factor slightly exceeding two, the number of species shows scant variation. This is despite the fact that the distances between the units differ considerably, with the distance between “E” and the car park being three times as long as the distance between the car park and “W” or the distance between “W” and “C”. This seems to suggest that surveys for species richness can capture a high proportion of the richness of an area by using a relatively short transect, of the order of 50-100m. The smallest observed number of species from a area in this study was 62, which is nevertheless 50% of the total of 125 species observed overall in the harvested areas.

Assemblage composition

From Table 1, it may be seen that there are major differences between the species composition of the harvested areas and the islands of the aggregated retention coupe 1E, and that there are also, perhaps more surprisingly, some differences between the species make-up in the islands and that in the mature forest 8J. Table 2 lists the most frequently occurring species faithful to the uncut forest and those faithful to the harvested, regenerating areas of 1E. The 10 species listed there as exclusive to the harvested areas are species that tend to be associated either with burnt environments, or are typical of disturbed or drier conditions. This fact was noted in our previous study (Gates et al. 2005), where some of these same species were observed, and reference was also made to similar findings from other studies.

Species that were frequently observed either in the mature forest or in the islands of 1E, or in both the mature forest and the islands, but not encountered in the harvested areas, are amongst the lists of species given in Tables 1 and 2. Boletellus obscurecoccineus, Lactarius clarkeae, Mycena toyerlaricola, Galerina ‘with sphaeropendunculate cheilocystidia’, Marasmiellus affixus, and Cortinarius ‘C62, varnished, golden brown …’ are prominent amongst the species found both in the mature forest and in the islands, but Stereum ostrea, Cantharellus concinnus, Podoserpula pusio and Pholiota squarrosipes were abundant in the mature forest but never recorded in the islands of 1E. Among the commonly observed species in this survey that were absent from the harvested areas, no species was found in the islands but not recorded in the mature forest. These findings suggest that, although the habitat of the islands is similar to that of the mature forest, the drying effect due to its proximity to the harvested areas impedes the full development of the macromycota.

Seasonality

The production of macrofungi is strongly correlated with season, with autumn and early winter generally being the most productive months for fruit bodies in Tasmania’s wet forests. Spring and summer can be wholly unproductive, unless there are rainfall events during those seasons that can stimulate the growth of mycelia and the initiation of fruit body production. There were no substantial rainfall episodes during the summer of 2004/2005, so fungal species numbers in the two treatments of the aggregated retention coupe remained low until rainfall increased, and drying effects due to long daylight hours decreased, with the onset of autumn. Species numbers were not as low during the spring and summer months in the mature forest, whose closed canopy provides resistance to the drying effects of longer, warmer days. During the spring and summer of 2005/2006, higher species numbers were obtained in both the islands and harvested areas of 1E in mid-October, mid-November, and mid- to late December (see Figure 5, which also includes the cumulative rainfall total during the seven days preceding sampling, obtained from the Bureau of Meteorology’s Warra weather station). Although the peaks of fungal fruit body production appear to be largely independent of rainfall events, reflecting season as the major influencing factor, on a finer scale some peaks, troughs, or deviations from the general trend can be seen to coincide with rainfall events of the previous week. This is most apparent in the higher species numbers obtained during the visits of 15 November 2005, 27 December 2005 and conversely, in the lower species numbers in the two visits in February 2006.

Figure 5. Species numbers in each of the three sampling units, viz. coupe 8J, islands of 1E, harvested areas of 1E, and cumulative rainfall during the preceding seven days (mm), plotted against date of visit.

Substrate

As was the case with our previous study (Gates et al. 2005), the present study has found that most fungi in these forests are found on soil or wood, with only 5.4% being non-specific to a substrate. The large number of species recorded on wood further demonstrates the important role of this substrate for the preservation of forest biodiversity. Amongst species exclusive to one or other of the two coupes, no difference in the proportions found on the various substrates was detected (Table 6), but within 1E, 69% of the species unique to islands were found on soil (Table 7). This result contrasts with species found only in the harvested areas, which are predominantly wood inhabitors. These findings broadly agree with the results reported by Gates et al. (2005, Table 1), where the species exclusive to the mature forest were found mainly on soil, but species found jointly in both coupes were mainly on wood. However, in that study, amongst the 59 species exclusive to the regenerating CBS plot, 56% were found on soil and 34% were found on wood, compared to 15% and 69%, respectively, in the present study. One explanation is that the harvested areas of the aggregated retention coupe of the present study are at an earlier stage of regeneration than that of the CBS plot of the previous study.

Main life mode

Mycorrhizal fungi play a very important role in Australian eucalypt forests, with an involvement in a wide variety of associations (Ashton 1976). In our earlier study of a CBS plot compared to an unlogged control (Gates et al. 2005), 70 mycorrhizal species were recorded, of which 84% were exclusive to the mature forest, with 7% of the mycorrhizal species being exclusive to the regeneration. In the present study, if mature forest is augmented by including the islands of 1E, then the corresponding percentages are 93 and 5%, respectively (Table 9). The paucity of the large ectomycorrhizal species, such as those of the Cortinariaceae and the Tricholomataceae in the regeneration, is a striking and important difference between the mycota of regenerating and mature forest. Work carried out in regenerating eucalypt forest in Victoria suggested that it may take seven years before large numbers of fruiting bodies of ectomycorrhizal species appear in the regeneration (McMullan-Fisher et al. 2002).

Although decomposer species greatly outnumbered the mycorrhizal species in the regeneration (Table 9), there were no Entoloma species found there, and only one Hygrocybe species (H. roseoflavida, two records) was seen. This parallels the results of our earlier survey (Gates et al. 2005), where only four of 14 Entoloma species identified in the survey were found in the regeneration and only one Hygrocybe species was seen. These results reflect the lack of litter in the regeneration, both in the previous and the present study.

Some additional observations

The aggregated retention coupe 1E of the present study was quite different from the CBS coupe studied previously (Gates et al. 2005) with respect to the degree and extent of burning that followed the harvesting operation. The harvested areas of 1E were not aerially sown after clearfell and burning but were meant to be seeded naturally either by a seed bank present in the soil or by seed dispersal from the retained islands in the coupe. The resulting regeneration was not as successful as that on 8H, which at age 26 months (commencement date of our earlier survey) was a coupe of flourishing Eucalyptus obliqua, Pomaderris apetala and Acacia verticillata seedlings forming dense thickets. In comparison, the regeneration in IE, which was 26 months old when our survey finished, had a few individual eucalypts of height 2-3 metres but nothing approaching the thick regrowth on 8H. This could also have been the result of excessive mammal browsing. The increased canopy of 8H meant the establishment of a new litter layer, thereby providing species of saprophytic fungal genera such as Entoloma, Hygrocybe and Mycena with a substrate to colonise. No corresponding litter layer was forming on 1E.

Several records of the early stage mycorrhizal fungus genus Hebeloma were made on 8H, suggesting that new mycorrhizal associations were being established from inoculum present in the soil. Laccaria spp., another group of early stage mycorrhizal fungi, were prolific in 8H. In the harvested areas of 1E, Laccaria spp. were also found but only on the snig track around East island and where the burn had encroached upon the periphery. Another species, Tricholoma sp. “red cap, very white gills”, was also found several times close to the periphery of the island although technically in the harvested area. Members of the genus Tricholoma are considered to be late-stage successional ectomycorrhizae fungi. This could suggest that the fruit bodies were still in association with a host tree on the island, the roots of which were still alive and were extending into the harvested area. Similarly, the Laccaria species, because of the proximity of the fruiting bodies to the island, may have still been in association with the living hosts on the island rather than the start of a new mycorrhizal association with a new host from inoculum in the soil. To distinguish between these two scenaria would involve a study of soil samples and roots from host plants from both coupes over many months (at least 36) starting from zero on a scale of time since fire.

An area of forest at the junction of Bennetts Road and Arve Road was accidentally burnt on 1 April 2005 by an out-of-control forestry regeneration fire, providing us with a site to monitor the fungal succession at fortnightly intervals for 12 months from the initial date of burning. Although this fire was a wildfire rather than a controlled regeneration burn, we regard it as being a useful adjunct to our present and previous work, being of a similar forest type and only 13 km from the Warra LTER silvicultural sites. Figure 6 shows the “time line” for the visits to Bennetts Road, to the aggregated retention coupe 1E of the present study, and to the CBS coupe 8H of the earlier study (Gates et al. 2005). The “zero” time in each case represents either the time after sowing (8H), or the end of site preparation (1E), or the date of the wildfire (Bennetts Road). The fungal survey at Bennetts Road commenced on 13 April 2005, and visits were made to the site 29 additional times on the same days that visits were made to 1E, giving an overlap of ca. 4 months between those two time lines. Since the study at 1E terminated at a point in time corresponding to ca. 26 months after the regeneration burn was applied to that coupe, coinciding with the time after burning at which we commenced our study of the CBS coupe 8H, the three studies taken together gave an unbroken period of 38 months for monitoring the succession of macromycota after fire in the lowland southern wet eucalypt forests.

In the 30 visits to the Bennetts road site, 273 records of 76 species were obtained. The list of species is given in Appendix 2, and may be compared to the corresponding list of species from the present study in Appendix 1. Of these 76 species, 41 of them (54%) were not observed in the regeneration of 1E, including Pyronema omphalodes, Neolentinus dactyloides, Peziza echinospora, Peziza tenacella,

Interpretation of the results in Figure 7 is straightforward, as there is a clear separation between the points representing the visits to Bennetts Road and the points representing the visits to 8H, with the points depicting the visits to the harvested areas of 1E falling between the two extremes. This is a consequence of the big difference between the species composition in the earliest stages of regeneration occurring in the first six months after the wildfire compared with the mycota present 26-38 months after a hot, regeneration burn was applied. The intermediate nature of the macrofungal species composition in the regeneration in 1E reflects both the earlier time since regeneration and the lower intensity of the burn, which left a fair amount of unburnt wood and logging residue in the coupe.

The site at Bennetts Road, being affected by a wildfire, still retained the host trees. This is one of the differences between a wildfire and a fire after clearfelling (Lindenmayer et al., 1990). Although the litter, understorey species and leaf canopy of the trees at Bennetts Road were completely burnt, the trees were coppicing 6 months after the fire. Many early stage successional fungi were found at this site in accordance with other studies on succession of fungi after wildfire (May and Fuhrer 1989; Petersen 1970; Warcup 1990). A survey by the authors (unpublished data) of a portion of a wet sclerophyll forest on the Tasman Peninsula, which had been burnt in the summer and surveyed during the fungal season of the following late autumn and early winter, found early successional fungi such as Peziza tenacella, Peziza echinospora, Pyronema omphalodes, and stone-maker fungi such as Laccocephalum tumulosum and Laccocephalum sclerotinium coming up alongside the late successional fungi such as species of Boletus, Russula and Amanita. This is because the host trees were not completely destroyed by the wildfire. As a result, biodiversity was maintained, the health of the forest trees enhanced as they recovered from the fire, and restoration of the ecosystem equilibrium was in process. It would be of interest to survey the Bennetts Road site in Autumn-Winter 2007 to see if this will also be the case after the wildfire of 1 April 2005.

Conclusions

This study is the second to document the rich mycota of contrasting coupes in the Tasmanian lowland wet eucalypt forests at Warra, following on from an earlier published study (Gates et al. 2005). Many new species are added to the list of 307 species recorded in that earlier study, bringing the concatenated list of species from 8H, 8J and 1E to 527 species. The extended Langmuir model given by Equation 1 has been shown to be an excellent empirical model to fit randomised species accumulation curves, and the results in Figure 3 and Table 4 suggest that many more species would be recorded if further survey effort is carried out.

The central importance for macrofungi of the substrates soil and wood, on which almost 90% of the mycota were found in the earlier study (Gates et al. 2005), has been confirmed by the present study, with at least 86% of the fungi being found on one or other of those two substrates. Forest management needs to be cognisant of results such as these if the preservation of biodiversity is to be an important consideration. In addition, consideration needs to be given to the use of larger islands in aggregated retention to reduce drying effects from the neighbouring harvested areas.

The earlier study (Gates et al. 2005) began 26 months after the regeneration burn, resulting in the earliest colonisers not being observed. The present study has added many more early colonising species, both from 1E, which began ca. 10 months after regeneration, and from the wildfire at Bennetts Road, which had a true “zero” commencement time. The latter area yielded 76 species, of which 41 were different from the species listed from 1E. It would be expected that further surveying effort would add to the 228 species observed in the regenerating areas.

Acknowledgement

The authors gratefully acknowledge the financial support in the form of a Warra small projects grant from Forestry Tasmania (Project F61857 FT). We thank Leigh Edwards of Forestry Tasmania for track preparation.

References

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Appendix 1. Fungal species found in coupes 8J and 1E (listed in alphabetical order).

Species binomial	Number of records		Habitat¹	Substrate²	Life mode³	Preferred season(s)⁴
	8J	1E
Aleuria aurantia (Fr.) Fuckel	0	10	H	SB & SUB	D	A,W
Amanita ‘A122, grey brown scab, white annulus, small spores’	1	0	J	Soil	M	Su
Amanita ‘A123, grey brown, glabrous’	2	1	U	Soil	M	Su,A
Amanita ‘A126, brown, applanate, lubricous, no annulus’	1	2	U	Soil	M	A
Amanita ‘A139, dry, white with some ochraceous tinges’	1	0	J	Soil	M	Su
Amanita ‘dark brown with grey universal veil remnants’	1	0	J	Soil	M	A
Amanita ‘grey with white scales & stipe, no volva’	1	1	U	Soil	M	A
Amanita ‘grey-brown, no annulus’	0	1	H	SUB	M	A
Amanita ananiceps (Berk.) Sacc.	1	0	J	Soil	M	A
Amanita effusa (Kalchbr.) D.A. Reid	1	0	J	Soil	M	A
Amanita ochrophylla (Cooke & Massee) Cleland	1	0	J	Soil	M	Su
Amanita ochrophylloides D.A. Reid	2	0	J	Soil	M	Su
Amanita pagetodes D.A. Reid	1	0	J	Soil	M	A
Amanita peltigera D. A. Reid	1	4	U	Soil	M	Su,A
Amanita punctata (Cleland & Cheel) D.A. Reid	0	1	U	Soil	M	Sp
Arcangeliella sp.	2	1	U	Soil	M	A
Armillaria hinnulea Kile & Watling	1	1	U	Wood	D	A
Armillaria novaezelandiae (G. Stev.) Herink	6	2	H & U	WUB	D	A
Ascocoryne sarcoides (Jacq.) J.W. Groves & D.E. Wilson	18	4	H & U	WB & WUB	D	A,W,Sp
Ascomycete ‘brown buttons, gelatinous disc’	0	1	H	LUB	D	W
Ascomycete ‘small buff gelatinous disc on cut wood face’	1	0	J	Wood	D	A
Ascomycete ‘white disc bruising orange’	5	0	J	Wood	D	A,W
Auriscalpium ‘warrensis’	5	3	U	Soil	D	W,Sp
Australoporus tasmanicus (Berk.) P.K. Buchanan & Ryvarden	1	0	J	Wood	D	Su
Bisporella ‘green-yellow’	7	3	H & U	WUB	D	A,W
Bisporella citrina (Batsch ex Fr.) Korf & S.E. Carp.	7	0	J	Wood	D	A,W,Sp
Bisporella sulfurina (Quél.) S.E. Carp.	2	0	J	Wood	D	W,Sp
Bolete ‘B174, pink cap and stipe, yellow tubes’	3	0	J	Soil	M	Sp,Su
Bolete ‘green-pink, with bright yellow tubes and pores’	1	0	J	Soil	M	Su
Boletellus obscurecoccineus (Höhn.) Singer	12	13	U	Soil	M	Su,A
Boletus ‘rosy brown’	4	0	J	Soil	M	Su,A
Boletus ‘Stephens’	0	1	U	Soil	M	Su
Boletus ‘wedgensis’	2	1	U	Soil	M	Su,A
Boletus ‘yellow and pink, blueing’	1	0	J	Soil	M	A
Bovista brunnea Berk.	1	2	H & U	SB	D	W,Sp,Su
Byssomerulius corium (Pers. : Fr.) Parmasto	0	11	H	WUB	D	A,W
Callistosporium ‘maroon on wood’	1	0	J	Wood	D	A,W
Calocera ‘spathulate’	3	2	H & U	WUB	D	Su,A
Calocera guepinioides Berk.	14	11	H & U	WB & WUB	D	All year
Campanella olivaceonigra (E. Horak) T.W. May & A.E. Wood	1	0	J	Wood	D	W
Cantharellus concinnus Berk.	13	0	J	Soil	D	Su,A
Ceriporiopsis subvermispora (Pilát) Gilb. & Ryvarden	1	0	J	Wood	D	A
Cheilymenia coprinaria (Cooke) Boud.	0	2	H & U	Dung	D	W
Cheimonophyllum candidissimum (Berk. & M.A. Curtis) Singer	1	0	J	Wood	D	A
Chlorociboria aeruginascens (Nyl.) Kanouse	2	0	J	Wood	D	Su,A
Chondrostereum purpureum (Pers.) Pouzar	4	0	J	Wood	D	A,W
Clavaria amoena Zoll. & Moritzi	2	0	J	Soil	D	A,W
Clavaria zollingeri Lév.

	Mature forest 8J	Unharvested islands of 1E	Harvested areas of 1E	Both coupes combined
Observed species richness ± 95% C.I.	288 ± 23.4	169 ± 15.8	125 ± 12.5	387 ± 23.4
Proportion of all species observed (%)	74.4	43.7	32.3	100
Estimated total species richness (extended Langmuir model) ± s.e.	607.4 ± 28.4	289.7 ± 5.4	249.1 ± 8.3	837.4 ± 25.6
Proportion of estimated species richness actually observed	47.4	58.3	50.1	46.2

Season: Survey unit:	Spring (S, O, N)	Summer (D, J, F)	Autumn (M, A, M)	Winter (J, J, A)	Probability (P-value)
8J	14.3b	17.4b	33.9a	34.9a	0.0075
1E (Islands)	7.0b	5.4b	15.1b	26.6a	0.0016
1E (Harvested areas)	9.6bc	5.9c	16.6b	28.0a	0.0007
1E (Total)	15.1bc	10.7c	28.9b	47.7a	0.0005
Diff: 1E(Harv.)-1E(Isl.)	2.6a	0.4a	1.5a	1.4a	0.9292
Diff: 8J-1E(Total)	-0.9a	6.7a	5.0a	-12.9b	0.0020
Diff: 8J-1E(Islands)	7.3b	12.0ab	18.8a	8.2b	0.0421
Diff: 8J-1E(Harvested)	4.7b	11.6ab	17.3a	6.9b	0.0296

Predominant substrate:	No. of species exclusive to the aggregated retention coupe1E	No. of species exclusive to the mature forest 8J	No. of species found in both coupes	Total number of species
Soil (S)	55 (55.6%)	94 (59.5)	56(43.1)	205
Wood (W)	32 (32.3)	54 (34.2)	42 (32.3)	128
Litter (L)	6 (6.1)	8 (5.1)	12 (9.2)	26
Other (Dung, Moss)	1 (1.0)	2(1.3)	4 (3.1)	7
Non-specific	5 (5.1)	0 (0)	16 (12.3)	21
Total no. of species	99	158	130	387

Predominant substrate:	In harvested areas only	In islands only	In both harvested areas and islands	Total number of species
Soil (S)	2 (15.4%)	45 (69.2)	9 (17.3)	56
Wood (W)	9 (69.2)	10 (15.4)	23 (44.2)	42
Litter (L)	1 (7.7)	6 (9.2)	5 (9.6)	12
Other and Non-specific	1 (7.7)	4 (6.2)	15 (28.9)	20
Total no. of species	13	65	52	130

Table 7. Numbers (and percentages of column totals) of species present in both coupes 1E and 8J, classified according to the sampling units of 1E in which they were found.

Table 9. Numbers (and percentages of row totals) of species classified according to treatment.