Commercial forest rotations are usually shorter than natural disturbance return intervals, which could affect the distribution of ectomycorrhizal fungal (EMF) species dependent on late-seral stands. We examined this potential reduction in species richness by comparing ectomycorrhizal mushroom communities across four age-classes (pole stage, young, mature, and old growth) of western hemlock (Tsuga heterophylla (Raf.) Sarg.) – lodgepole pine (Pinus contorta Dougl. ex Loud.) stands on submesic sites in northwestern British Columbia. Almost 130 species of ectomycorrhizal mushrooms were identified over the 12 sites during the 3-year study period. EMF richness was lowest in pole stands and almost twice as high in the older age-classes. Species composition and abundance were related to stand age, with relatively large differences in communities between the ages of 20 and 120 and relatively smaller differences between 120 and 225 years. Twelve species, including the economically important pine mushroom (Tricholoma magnivelare (Peck) Redhead), were late-seral stand dependent, fruiting in forests that are at least older than 85 years. This distribution of ectomycorrhizal mushrooms across stand ages suggests EMF succession is primarily an accumulation of species and is likely affected by differences in dispersal by ectomycorrhizal fungi, soil properties (increased soil acidity and reduced nitrogen availability), and the rate of stand development. The evidence for EMF species limited to late-seral stands supports the maintenance of some mature forests within these landscapes to conserve EMF richness.

The objective of this study was to examine the effects of stand age and tree species composition on the abundance, diversity, and community composition of epigeous fruit bodies formed by ectomycorrhizal (ECM) fungi in the Interior Cedar Hemlock zone of British Columbia. Fruit bodies were collected and identified in May, June, August, September, and October of 1996, 1997, 1998, and 1999 from transects located in new (5 year old) plantations and mature (75–125 year old) wild forests composed of relatively pure Betula papyrifera Marsh. (paper birch), relatively pure Pseudotsuga menziesii var. glauca (Beissn.) Franco (interior Douglas-fir), and mixtures of the two tree species. A total of 187 fungal taxa were collected during the study, of which 185 occurred in mature forests and only 17 occurred in the plantations. Thirty-four taxa were unique to mature predominantly birch forests, 35 were unique to mature predominantly Douglas-fir forests, 17 were unique to mixed mature forests, and 68 taxa were found in all three mature forest types. The abundance of fruit bodies in mature forests varied widely among sampling years and generally increased with annual precipitation. ECM species richness differed between stand ages but not among forest compositions in both plantations and mature forests. Lactarius glyciosmus , Hygrophorus eburneus var. eburneus , and Cortinarius armillatus were more abundant in mature birch than mature Douglas-fir forests. Lactarius torminosus , Leccinum scabrum var. scabrum , and Rozites caperatus were also found predominantly in mature birch and mixed forests, whereas Gomphidius subroseus was more abundant in Douglas-fir forests than in birch and mixed mature forests. Russula brevipes was also found predominantly in mature Douglas-fir and mixed forests. Our results indicate that clearcutting has a profound effect on abundance and composition of ECM fruit bodies, and that changes in forest tree species composition may lead to shifts in ECM fungal community composition.

Soil fertility and associated nitrogen (N) status was a key ecosystem attribute, and surveys of ectomycorrhizal fungal (EMF) communities via epigeous fruiting bodies could provide an effective biotic indicator of forest soil productivity. We explored the utility of aboveground EMF communities in this regard by surveying sporocarps over a 3-year period from contrasting plant associations of southern old-growth boreal forests of British Columbia (Canada). Cumulative richness ranged from 39 to 89 EMF species per plot (0.15 ha) and followed a skewed parabolic correlation with foliar N concentrations and soil N availability. EMF species composition was consistently distinct in ordinations and strongly correlated to the increasing rates of N mineralization aligned with soil productivity. Approximately 40 EMF species were specialists, as they collectively indicated oligotrophic, mesotrophic, and eutrophic nutrient regimes, while the remaining species were categorized as broadly tolerant (distributed over 100% of the N gradient), partially intolerant (approximately 70%), or satellites (rare). The functional organization of EMF communities reflected by distribution classes could help define the ecological integrity of forests, which was characterized in this boreal landscape by an average allotment of 20 broadly tolerant, 25 partially intolerant, 15 specialist, and ten satellite species per plot. Epigeous fruiting bodies provided a disparate yet complementary view to the belowground assessment of EMF communities that was valuable in identifying indicators for ecosystem monitoring.

During the summer of 1986, plants were collected from University of British Columbia Research Farm at Oyster River, Vancouver Island, and their mycorrhizal status was determined. Of the 60 plant species examined, 44 were always vesicular–arbuscular mycorrhizal, 13 were always nonmycorrhizal, and three varied. Nonmycorrhizal plants were found in species belonging to the following families: Araceae, Caryophyllaceae, Compositae, Cruciferae, Gramineae, Onagraceae, Polygonaceae, and Portulacaceae. The mycorrhizal status of 15 plant species is reported here for the first time. Of these, the nonmycorrhizal species included Lysichitum americanum (Araceae), Stellaria simcoei, Stellaria calycantha (Caryophyllaceae), and Epilobium minutum (Onagraceae), and the mycorrhizal species included Adenocaulon bicolor, Eriophyllum lanatum var. achillaeoides, Grindelia squarrosa var. serrulata (Compositae), Poa gracillima (Gramineae), Brodiaea coronaria, Disporum hookerii (Lilaceae), Polypodium glycyrrhiza (Polypodiaceae), Ranunculus uncinatus (Ranunculaceae), Rosa nutkana var. nutkana (Rosaceae), Collinsia parviflora (Scrophulariaceae), and Viola glabella (Violaceae).

Highlights from the Northwest Territories BioBlitzes

Ectomycorrhizae are fungus-root associations that comprise the feeder roots of most commercially important conifers in British Columbia. A large body of research has been conducted on ectomycorrhizae as they relate to forestry in the province; however, much of this information is scattered and is generally of a highly technical nature.This extension note summarizes the latest research on ectomycorrhizae, including information on the role that ectomycorrhizal fungi play in forest ecosystems. The authors discuss several helpful forest management practices that can maintain a diverse community of ectomycorrhizal fungi across the landscape. These include: retaining refuge plants, mature trees, and old-growth forests; retaining the forest floor during harvest and mechanical site preparation; avoiding high-intensity broadcast burns; minimizing the effects of species shifts, particularly following grass seeding; maintaining the edge-to-area ratio of harvested areas within certain limits; planting a mixture of tree species soon after harvest; retaining coarse woody debris; and managing for the fruiting bodies formed by ectomycorrhizal fungi, including edible mushrooms and truffles, fungi species used by wildlife, and rare and endemic species.

No abstract