Identifying Valuable Sites

The first attempts to identify important areas for the conservation of saproxylic fungi in Europe were launched in boreal Scandinavia in the early 1990s (H0iland and Bendiksen, 1991; Karstrom, 1992). The approach was based on lists of indicator species, including fungi, assumed to indicate not only valuable habitats for the organisms themselves, but forest with high local continuity and conservation value in general. The concept has since been widely applied in Scandinavia (Kotiranta and Niemela, 1996; Bredesen et al., 1997; Nitare, 2000), and more recently in several countries across Europe (Parmasto and Parmasto, 1997; Heilmann-Clausen and Christensen, 2000; Nordstedt et al., 2001; Holec, 2003; Luszczyiñski, 2003; Ainsworth, 2004; Walleyn and Veerkamp, 2005).

In Scandinavia the use of saproxylic fungi as indicators of ecological continuity has been heavily criticised (Rolstad et al., 2002; Norden and Appelqvist, 2001), due to lack of statistical support from field studies and the obvious potential of fungi for long distance dispersal. Norden and Appelquist (2001) thus noted that saproxylic fungi in general are likely to depend on a rich supply of dead-wood habitats, rather than the presence of long local forest continuity. Following this argument, and backed by actual results from field studies, several authors (e.g. Simila et al., 2004; S^tersdal et al., 2004, 2005) have argued that structural indicators (e.g. amount and quality of dead wood) rather than indicator species are relevant in identification of valuable sites for conservation of saproxylic organisms, including fungi.

Other studies, mainly over larger geographical scales (tens to hundreds of kilometres), have however shown that the frequency of threatened saproxylic fungi cannot be predicted solely based on easily monitored dead-wood parameters, but that factors related to forest history at the landscape scale have a marked effect on species composition (Sverdrup-Thygeson and Lindenmayer, 2003; Stokland and Kauserud, 2004; Heilmann-Clausen and Christensen, 2005; (Odor et al., 2006; Pentilla et al., 2006). Christensen et al. (2005) suggested sap-roxylic fungi to be particularly suited as indicators of dead wood and veteran tree continuity at the landscape scale (25-10,000 ha), and Strange et al. (2004) used indicator species to model the efficacy of fungal conservation in reserve networks in time and space. Both applications may prove very useful in a conservation context: the first, because dead wood continuity in space and time is difficult or even impossible to investigate at the appropriate scale; the second, because localised conservation efforts are likely to prove unsuccessful for species showing population dynamics at the landscape scale. Scientific testing of indicator schemes based on saproxylic fungi is much needed to determine how relevant they are for monitoring and management of threatened saproxylic fungi and other groups of organisms associated with old growth forest habitats. In Figure 3, an example of practical application of saproxylic fungi as indicators of valuable habitats in Denmark is illustrated.

3.3 Recommendations for the Future

Conservation mycology is still in its infancy, and has not yet received the same attention as animal and plant conservation. Above we have discussed different challenges and approaches relevant for fungal conservation and reviewed the current situation for saprotrophic basidiomycetes in grassland and on dead wood. We believe that indicator species and red-lists are useful means to put fungi on the overall conservation agenda and, in practice, to identify valuable sites for conservation. However, focussed initiatives to increase both the scientific and more broad understanding of conservation mycology are required. Relevant issues include:

(1) Lobbying to stimulate public and political awareness of fungi as organisms worthy of protection. Positive examples, such as successful

Number of indicator species >25 (International importance) O 20-24 (National importance) O 15-19 (Regional to national importance) O 10-14 (Local to regional importance) o 5-9 (Potential importance)

Figure 3 Map showing localities with five or more indicator species of valuable beech forest habitats (Heilmann-Clausen and Christensen, 2000) in Denmark. Encircled areas contain one to several larger forest reserve, > 50 ha, containing protected, old grown beech stands. The map shows that valuable sites occur clumped at the landscape scale and that one important region containing several valuable localities (arrowed) currently is insufficiently protected (adapted from Heilmann-Clausen, 2005).

Figure 3 Map showing localities with five or more indicator species of valuable beech forest habitats (Heilmann-Clausen and Christensen, 2000) in Denmark. Encircled areas contain one to several larger forest reserve, > 50 ha, containing protected, old grown beech stands. The map shows that valuable sites occur clumped at the landscape scale and that one important region containing several valuable localities (arrowed) currently is insufficiently protected (adapted from Heilmann-Clausen, 2005).

protection schemes for fungi (e.g. Naturvardsverket, 2006) and protection of important fungus localities, deserve promotion to a broader public as demonstration projects. Inclusion of fungi in international conventions, e.g. in the EU Natura 2000 program, must be a goal.

(2) Elucidation of the extent to which existing conservation schemes such as nature reserves, National Parks and the Natura 2000 program protect threatened fungi.

(3) Increased focus on identifying fungi threatened at the international scale is much needed. Work is underway to create a European red-list, coordinated by ECCF (2006).

(4) Many research issues are relevant but the following are among the most urgent questions: (i) How should valuable sites be identified for inclusion in reserve networks—are indicators (species or structures) useful, or is it more effective to focus directly on selected priority species (e.g. internationally threatened species)? (ii) As pointed out by Jonsson et al. (2005), wood-inhabiting fungi are structured as metapopulations. This implies that local population sizes are unstable and variable over time even

though the total population size is stable. How does this affect populations of threatened species in fragmented landscapes, where dead-wood habitats are highly agglomerated spatially in protected forest reserves, and what are the consequences for design of reserve networks? (iii) To what degree do fungi associated with more stable habitats (e.g. grassland fungi) function as metapopulations and what is the level of genetic exchange among sites in a fragmented landscape? Do we risk a widespread local extinction of threatened species in small, isolated protected sites, even if local habitat qualities are protected? (iv) How important are resting non-sporulating mycelia for the resilience of local populations of threatened fungi, and how long is the typical lifespan of mycelia of various species?

0 0

Post a comment