Message - 7th IAL Symposium

1A-O
Lichen: from genome to ecosystem in a changing world
(1A – O10) Submission ID: IAL0019-00001
OLD, ARTIFICIALLY DRAINED SWAMP FORESTS PROVIDE VALUABLE HABITATS
FOR LICHENS: A COMPARATIVE CASE STUDY FROM ESTONIA
Lõhmus P. 1
1 Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia
In the boreal region, forested wetlands have been frequently drained in order to increase timber yields,
while the accompanying impacts on biodiversity have received relatively little attention. At present, drained
peatland forests cover 14% of the Estonian forest land, including large areas in reserves. Particularly in the
nutrient-rich swamp site type, the biodiversity value of those forests is important to assess because old natural
swamp forests have only survived as small remnants. I studied whether old, structurally rich drained forests can
support threatened lichen species, which primary habitat swamp forests. For that, I used a fixed-area fixed-effort
method to describe species richness and composition of lichens* in 20 undrained and 24 drained stands, each
2 ha in size. They represented, in a block design, 4 treatments (old-growth and mature stands; retention-cut and
clear-cut plots) in 5–6 replications. The total species richness of natural and drained swamp stands was similar:
209 vs. 211 species in forests, and 176 vs. 177 in cut plots, respectively. Based on MRPP tests, the species composition
of natural old-growth forests differed significantly from the other three forest stand combinations (those
formed a relatively homogeneous group). However, the number of nationally protected, threatened and/or rare
species** was similar or even higher in artificially drained forests compared to natural swamp forests (in total,
29 vs 27 in old-growth and 19 vs 10 in mature stands, respectively). For example, Cetrelia olivetorum, Lobaria
pulmonaria and Parmeliella triptophylla were always found from old-growth stands, irrespective of the incidence
of drainage. The availability of old deciduous trees, large snags, and logs and root plates of tree falls seems to
be more crucial for most lichens than the microclimatic changes putatively attributed to drainage. Possibly, the
thick carpet of mosses developing after ditching is important for holding a favorable moist microclimate. Hence,
despite being developed under human impact, old artificially drained swamp forests can be considered valuable
habitats for lichens in nature conservation planning.
* includes also lichenicolous and saprobic fungi traditionally treated by lichenologists
** lichenicolous fungi not included
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