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Mycologia. 103(6),2011, pp. 1175-1183. DOl: 10.3852/10-388 r[" 2011 by The Mycological Society of America, Lawrence, KS 66044-8897 95% of basidiospores fall within 1 m of the cap: a field- and modeling-based study Tera E. Galante) means that environmental factors, not dispersal Department of Forest and Wildlife Ecology, University of limitations, influence the observed range of EMF Wisconsin at Madison, 120 Russell Labs, 1630 Linden species (Finlay 2002). However studies have shown Drive, Madison, Wisconsin 53706-1520 that this is not always the case (Dickie and Reich 2005, 2007, 2009, 2010) Thomas R. Horton Peay et al. Nunez et al. Peay et al. 2010 Department of Environmental Forest Biology, SUNY (see Dickie et al. for details) and colonization of ESE', 350 Rlick Hall, 1 Forestry Drive, Syracuse, New host tree species by basidiospore inoculum is difficult York 13210 to achieve. For EMF species to be successful in basidiospore-based reproduction they need to effec Dennis P. Swaney Department of Ecology and Evolutionary Biology, E309b tively disperse their basidiospores. Two dominant Corson Hall, Cornell University, Ithaca, New York vectors of EMF basidiospore dispersal are animals 14853 (Maser and Maser 1988, Cazares and Trappe 1994, Johnson 1996, Lilleskov and Bruns 2005, Ashkannej- had and Horton 2006) and wind (Allen 1987). This Abstract: Plant establishment patterns suggest that study focuses on the importance of wind dispersal for ectomycorrhizal fungal (EMF) inoculant is not found EMF basidiospores. ubiquitously. The role of animal vectors dispersing Most EMF basidiospores are under 10 �m long, and viable EMF spores is well documented. Here we sporocarp production is in the range of 1 X 109 investigate the role of wind in basidiospore dispersal basidiospores per sporocarp (Buller 1909). Their size for six EMF species, Inocybe lacera, Laccaria laccata, and abundance should allow for long distance Lactarius rufus, Suillus brevipes, Suillus tomentosus dispersal by wind to other habitats (:Suller 1909, and Thelephora americana. Basidiospores adhered to Lacey 1996). But EMF species differ in their ability to microscope slides placed on three 60 cm transects produce and disperse basidiospores. In an island radiating from sporocarps. Morphological character biogeography study it was shown that species that istics of species as well as average basidiospore volume invest heavily in dispersal are more likely to colonize were recorded. Number of basidiospores was quanti small and distant tree islands, but as the tree islands fied at specific distances to produce actual dispersal begin to grow and develop other, presumably more gradients. We found a negative exponential decay competitive species, are able to establish and replace 2007). model using characteristics for each species fit the the initial colonizers (Peay et al. These results field data well. The 95% modeled downwind dispersal are driven initially by differences in dispersal ability of (1990) distance of basidiospores was calculated for each the fungi. Borchers and Perry and Dickie and (2005) species. The 95% modeled downwind dispersal Reich corroborate this idea by reporting that distance increased with increasing cap height and increasing distance from the forest edge reduced the decreasing basidiospore volume for the species amount of EMF inoculum available. sampled, with 95% of basidiospores predicted to fall Much of the work done on basidiospore dispersal within 58 cm of the cap. Differences in anatomical thus far either has been inferred through genet studies 1994, 2004, characteristics of EMF species influence how far (Dahlberg and Stenlid Kretzer et al. 2006) basidiospores are dispersed by wind. We discuss the Dunham et al. on pathogenic species (Fitt and 1986) role of wind dispersal leading to patterns of EMF McCartney or on arbuscular mycorrhizal fungi 1987, 1989). establishment during primary succession. (Warner et al. Allen et al. A significant Key wards: dispersal model, ectomycorrhizal es amount of work has been done on saprotrophic fungal 1961, tablishment, primary succession, wind dispersal basidiospore dispersal (Gregory et al. Haard and Kramer 1970, McCracken 1972, Rockett and Kramer 1974, Kay and Vilgalys 1992, Norden and Larsson INTRODUCTION 2000). While saprotrophs are probably the most similar A common misconception regarding EMF basidia to EMF in dispersal patterns, there are differences in spores is that "everything is everywhere, but the dispersal height and growth habit (on standing or environment selects" (Baas-Becking 1934). This prone trees) as well as length of the dispersal period, with many conks producing basidiospores over an Submitted 30 Nov 2010; accepted for publication 19 Apr 201l. entire season. Because of these differences there is a 1 Corresponding author. E-mail: [email protected] need for more study of EMF basidiospore dispersal. 1175 1176 MYCOLOGIA Currently in the literature these types of studies are Siuslaw National Forest, Oregon, USA. Mild temperatures limited. Allen (1987) reported that in the primary and abundant precipitation characterize the climate of the successional tephra zone deposited after the 1980 area with little or no seasonal moisture deficiency (Wiede mann et al. 1999). Weather reports generated 1971-2000 Mount St Helens eruption only one ectomycorrhizal show an average yearly high of 15.5 C, an average low of Thelephora basidiospore was captured from the air 24 6.9 C, and an average yearly precipitation of 162.8 cm stream per trap h. While this is important in (45.472°N, 124.267°W) (©2010, PRISM Climate Group, showing that EMF basidiospores are present in the Oregon State University). Wind speeds recorded at the airstream and available for establishment, it is un Newport, Oregon, marine buoy (Station 46050), roughly known how far these basidiospores traveled and why 80 km north of the study site indicated that velocity is Thelephorawas the only EMF species with basidiospores highest in Nov-Feb and lowest in Jun-Aug (National found in the airstream. Another study by Li (2005) Oceanic and Atmospheric Administration, www.wrh.noaa. found that less than 5% of basidiospores released from gov). The summer winds generally originate from N-NW, the winter winds from S-SW, and the fall and spring winds the ectomycorrhizal species Amanita muscanavar. alba are transitional between the two (Wiedemann et al. 1999). dispersed as far as 5.2 m from the sporocarp. Li (2005) The study ecosystem is composed of four zones: a does a good job in quantifying basidiospore amounts at foredune that parallels the ocean, the deflation plain forest, distances from a sporocarp but addresses only one the dune system and the original stable forest to the east cluster of fruiting bodies from one species and does (see Ashkannejhad and Horton 2006 for details). This work not measure dispersal immediately adjacent to the was done on the edge of the deflation plain forest adjacent caps. These studies, especially those on saprotrophic to the open dune system. The dominant ectomycorrhizal and EMF species, have been seminal in improving our (EM) tree species is Pinus contorta var. contorta. Other EM understanding of basidiospore dispersal. The purpose host trees include Picea sitchensis Bong. Carr., Pseudotsuga of the present study was to investigate EMF basidio menziesii Mirb. Franco and Tsuga heterophylla Raf. Sarg. 1 spore deposition within m of the sporocarps of six Sporocarp selection.-Six EMF species were chosen for species in five genera. sampling: Suillus brevipes, Suillus tomentosus, Inocybe lacera, We investigated wind dispersal on the Oregon Laccaria laccata, Thelephora americanaand Lactarius rufus. coastal sand dunes in the Oregon Dunes National These species were chosen based on their abundant fruiting Recreation Area in the Suislaw National Forest, in the area and potential for establishment in early Oregon, USA. Research by Ashkannejhad and Horton successional settings. Five healthy individuals with expand (2006) showed that the dominant fungi on seedlings ed pilei from each species were selected opportunistically over 5 d, and all other sporocarps within a 5 m radius were in isolated areas of the sand dunes without existing removed to reduce background spore noise. EMF networks were suilloid fungi (Suillus and Rhizopogon spp.). These were also the dominant Data collection.-Dispersal sampling occurred from 22-27 EMF inoculant found in deer feces in the area, Oct 2008 (TABLE I). For each individual three transects were leading to the conclusion that deer are one of the set up, running 0-60 cm from the sporocarp and oriented main long distance dispersal agents of primary radially around the sporocarp at 0°, 120°, 240°, with 0° successional epigeous and hypogeous basidiomycetes oriented in the prevailing downwind direction (toward the southeast during summer months). Each transect had five on the sand dunes. The role of wind in the dispersal microscope slides on it at 1-5, 10-15, 25-30, 40-45, and 55- of the epigeous basidiomycetes was not addressed. 60 cm from the sporocarp for a total of 15 slides/sporocarp The objective of the present study was to investigate (FIG. 1a). Slides were dipped into a hot solution of 90% EMF basidiospore dispersal by wind. These six species petroleum jelly, 10% paraffin wax and allowed to cool to a of EMF were selected based on their putative role in thin, even surface that would trap impacting basidiospores. early successional habitats, variation in basidiospore Petroleum jelly was used