Lichen, bryophyte and vascular plant species diversity in forests
Data about the richness of flora and fauna of Latvian forests is very
heterogeneous, and the level of research of different organism groups
greatly differ both in Latvia as a whole and in forest habitats.
Studies of species diversity in Latvian forests are not published up to
now. Only fragmentary data is available and concerns separate plant and
animal groups. Quite large information is available on vascular plant flora.
Analysis of parcial flora (ecologically uniform areas - ecotope) was carried
out in many protected nature areas (Gavrilova, Laiviņs, 1992; Bambe, 2001
etc.), occurrence of vascular plant species in the forest types was studied
by K. Buss (1964). There are several studies about bryophyte occurrence in
different habitat types (Āboliņa, 2001; Bambe, Lārmanis, 2001; A. Āboliņa,
(not published.) etc.).
Lichens
In Latvian forests, over 304 lichen species occur that is about 60.3 % of
the total lichen flora of Latvia. Among them, 160 species belong to crustose
lichens, 55 to leaf lichens and 89 species to fruticose lichens. The largest
lichen species number concentrates in 10 families. These must be considered
as more polymorphic - dominating lichen species in Latvian forest flora.
These families include 223 species that comprises 73.4 % of the total lichen
species number found in the forests. Only 81 species belong to the other
families that is 26.6 % of the total species number.
In Latvian forests, 47 lichen species occur that are included in the List
of Protected Plant Species according to the Regulations of the Cabinet of
Ministers. It is an important part of all protected lichen species (84.0 %).
Among them, 25 species are included in the Red Data Book of Latvia.
Bryophytes
In Latvian forest habitats, 298 bryophyte species occur (58% of the total
species number of Latvian bryophyte flora) and include species from 120
genus and 52 families.
In the list of the EU Directives and 6th Resolution of Bern Convention 3
bryophyte species occurring in Latvian forests are included:
| Buxbaumia viridis (Moug. ex Lam. et DC) Brid.ex
Moug. et Nestl. |
|
| Dicranum viride (Sull. et Lesq.) Lindb. |
|
| Plagiomnium drummondii (B. et S.) T.Kop. |
|
In Appendix V of the EU Directives (plant and animal species that are of
community interest and whose picking and exploitation in nature can be
allowed) one species that grows in Latvian forests is included:
Leucobryum glaucum (Hedw.) Ångstr.
Vascular plants
Latvian forests provide a habitat for 656 vascular plant species from 79
families and 305 genus. It comprises 40% of the total vascular plant number
in Latvian flora. It must be mentioned that from the total number of species
growing in forests foreign species (adventive species and garden escapers)
comprise only 5 %, but in Latvian flora their density is much higher - about
30%. Concerning the local (autohtone) species, forest significance is even
higher - it is the habitat for 51% of autohtone species.
In forests, the richest is Rosaceae family that in the whole
Latvian flora is only on the third place. The species richest family of
Latvian flora - Poaceae family and Compositae family in the
forest flora is on the third and fourth positions. Several families, like
Aspidiaceae syn. Dryopteridaceae, Pyrolaceae occur only in forests,
but for 80% species of Violaceae, Ericaceae, Campanulaceae,
Lycopodiaceae, Orchidaceae, Caprifoliaceae forests are the most suitable
habitat.
Forests are very important for the protection of Latvian rare and
protected plant species. In forests, 111 especially protected plant species
(51% of all protected species) and 143 Latvian Red Data Book species occur.
Only about a half (46%) of all protected species can be maintained outside
forests, but the other species can grow only forests, and in rare cases in
habitats that are associated with forests.
From species that are included in international documents, 11 species
occur in forests (in total in Latvia there are 21 such species). Both in EU
Directive 92/43/EEC on the Conservation of Natural Habitats and of Wild
Fauna and Flora and Bern Convention, such species as Cypripedium calceolus,
Pulsatilla patens, Thesium ebracteatum un Neottianthe cucullata are
included. In the EU Directive and also 6th Resolution of the Bern Convention
also Cinna latifolia, Agrimonia pilosa, Sorbus teodorii and
Dianthus arenarius subsp. arenarius are included, but in Bern
Convention - Botrychium matricariifolium, B.multifidum and
Dracocephalum ruyschiana.
