LINEAMIENTO PARA EVALUAR LA PROPUESTA

6.1

New species – research efforts

This research shows, despite earlier beliefs that the Finnish Auchenorrhyncha fauna would be quite well known because of the country's earlier prominent researchers, that it has been quite poorly investiga- ted. Today 389 species are known from Finland, i.e. 56 (17%) more than when the conservation status of the Finnish species last, in year 2000, was evaluated. Of the newly discovered species 13 (Anacerata-

gallia lithuanica, Aphrodes bicincta, A.diminuta, Balclutha arhenana, Cicadula ciliata, Edwardsiana lanternae, E.plurispinosa, Linnavuoriana intercedens, Oncopsis avellanae, Paralimnus zachvatkini, Metalimnus obtusus, Ribautodelphax vinealis and Scleroracus orichalceus) have been found as a result of more thorough taxonomic studies, 15 (Adarrus multinotatus, Balclutha boica, Cosmotettix evanescens, Delphacodes capnodes, Edwardsiana

tersa, Laburrus impictifrons, Macropsidius sahlbergi, Macrosteles oshanini, Mongolojassus bicuspidatus, Perotet- tix orientalis, P.pictus, Pinumius areatus, Psammotettix lapponicus, P. slovacus and Scleroracus identicus) are regarded as old species, which populations have been found with more focussed field inventories, 25 (Acanthodelphax spinosa, Acericerus heydenii, Alebra albostriella, A.neglecta, A.wahlbergi, Anakelisia perspicillata,

Calamotettix taeniatus, Cicadula nigricornis, Edwardsiana gratiosa, E.lethierryi, Eupterycyba jucunda, Eupteryx stachydearum, Eurybregma porcus, Fagocyba carri, Kelisia confusa, K.praecox, Kybos volgensis, Macropsis scutel- lata, Metalimnus steini, Parapotes reticulata, Stenocranus fuscovittatus, Typhlocyba quercus, Igutettix oculatus, Xanthodelphax xantha and Zygina angusta) are regarded as expansive species that have established native populations in the 21st century and  species (Circulifer haematoceps, Tremulicerus distinguendus, Edward-

siana ampliata and Ommatidiotus inconspicuus) are considered possible long-range migrants.

The increase of species in the 21st century is thus partly explained by more intensified research and inventory, partly by suitable climate conditions enabling species to expand their range to Finland from nearby core areas.

Despite present research efforts, there are still many species to be expected to occur in Finland, because they are quite abundant in neighbouring regions. Thus, more than 20 species not found in Finland occur in Estonia south of the Finnish Gulf. The true number of Finnish species may be close to 00.

6.2

Faunistic results

Diversifying the methods of inventory has considerably improved the knowledge of the distribution of species. The methodological results show that more than 60% of our species may be captured with light-traps, 0% by yellow-traps, circa 60 % by Malaise-traps and 20-25% by pitfall traps. During the research more than 1,000 new provincial records were made, largely supported by the new collecting techniques.

6.3

Biological results

The occurrence of species is only partly explained by the vegetation/plants of the sites. The edaphic conditions (substrate affinities) often play a major role in the choice of breeding sites.

The distribution of Finnish species with regards to priority habitats (= habitats for breeding) is shown in table 2. The arboricol portion of the fauna is ca 1/3 and the non-arboricol portion 2/3. This is due to the high number of monocot host-plants of the fauna. Notable high species numbers is recorded for esker forests, hemiboreal broad-leaved forests, dry grasslands, lacustrine shore meadows and ruderal areas, all which are sensitive to change (see subchapter 7.2). Species poor habitats are subarctic habitats, croplands and dry coniferous forests. Also the subtype "old boreal forest" has a low number of species. The future development of this habitat type, important for saproxylic species in Finland, is therefore not very decisive for the Finnish Auchenorrhyncha fauna.

Table 1.

Substrate affinities of the Finnish species

Affinity Definition S % of all

Arboricol Requires trees and brushwood for development 106 27.3

Psammobiont All sites on exposed sandy soil 4 1.0

Psammophilic Prefers (> 80% of sites) exposed sandy soil 26 6.7

Xerophilic Prefers dry mineral soil and dry ombrotrophic bogs 67 17.3

Mesophilic Prefers humid fine-grained soil 73 18.8

Hygrophilic Prefers wet organic sites 89 22.9

Tyrphobiont All occurrences on peaty soil 20 5.2

Halobiont All occurrences on saline soil 3 0.8

Table 2.

Priority habitats of the Finnish species

Forests total (M) 106

Boreal forests unspecified (Mk) 6

Dry coniferous forests (Mkk) 4

Esker forests (Mkh) 19

Small-leaved boreal forests (Mkt) 41

Lush boreal forests and groves (Mkl) 10

Hemiboreal forests and groves (Ml) 26

Anthropogenic habitats (I) 139

Woody pastures (Ih) 7

Ruderal areas (Ij) 31

Dry grasslands (In) 53

Fresh grasslands (It) 24

Wet grasslands (Ik) 9

Parks and gardens (Ip) 13

Crop fields (Iv) 2

Boreal rocky surfaces (K) 1

Subarctic heaths (Tk) 3

Subarctic meadows (Tn) 1

Water bodies (V) 1

Shores total (R) 80

Sandy Baltic shores (Rih) 7

Rocky Baltic shores (Rit) 1

Baltic shore meadows (Rin) 20

Lacustrine shores unspecified (Rj) 4

Gravelly lacustrine shores (Rjt) 2

Lacustrine shore meadows (Rjn) 47

Mires total 57

Mires unspecified (S) 2

Wet paludified forests (Sk) 10

Ombrotrophic bogs (Sr) 11

Oligotrophic fens (Sn) 30

Minerotrophic fens (Sl) 3

Table 3.

Comparison (in percent) of host specialization of Auchenorrhyncha nymphs between Germany and Finland.

Degree Germany Finland Definition of host specialization

1st _{degree monophagous 38,6 41,1 Restricted to 1(-2) plant species}

2nd _{degree monophagous 20,6 17,8 Restricted to 1 plant genus}

1st _{degree oligophagous 17,7 27,4 Restricted to 1 plant family}

2nd _{degree oligophagous 6,4 11,1 Restricted to 2 related plant families}

polyphagous 14,3 2,7 Feeds on > 2 plant families

unknown 2,3 0,0

Host specialization of nymphs is high in Finnish Auchenorrhynca. If using the classification developed by Nickel (2003) a comparison between Germany and Finland is possible (table 3).

The table indicates that Finland has relatively more 1st _{degree monophages and oligophages and much}

less polyphages, which may be explained by the restricted food supply, i.e. plant species, in the northern part of the range of many species.

The spectrum of plant genera that host monophages in Finland does not markedly differ from the spectrum in Central Europe (see Nickel 2003). Altogether 35 plant genera have monophages in Finland. The ten most important plant genera for plant- and leafhoppers are (number of monophages in bracken):

Carex (37), Salix (17), Calamagrostis (13), Festuca (12), Phragmites (10), Populus (10), Alnus (9), Betula (8), Ag-

rostis (8), Eriophorum (7). Fescue and alder have more prominent roles in Finland than in Central Europe, because they stand as alternative hosts in Finland for species that have specialized on other host plants (e.g. Corynephorus and Quercus) further south.

The high specialization degree and affinity of the species increase the rarity of many Finnish hoppers and also the threat to extinction of local populations. Thus, planthoppers and leafhoppers must be regar- ded as good indicators for ecological research and studies on effects of land use management.

The success in reproduction and distribution of species are furthermore determined by stages of hibernation and growth speed. Of the Finnish species 71.5 % hibernate in the egg stage, 18.1 % in the nymphal stage and 9.8 % as adults.

Kontkanen (195) reported only two species as having more than one generation in Finland. It is now evident, based on records of nymphs and adults, that the number of species regularly producing two generations per year is more than tenfolds higher. In addition, some normally monovoltine species may in favourable years with long warm autumns produce a partial second generation in southern Finland. The data on mono- vs. bivoltine species is still incomplete and much more detailed phenological records of nymphs are required to clerify the true picture in different parts of the country. For example, some mo- novoltine species hibernating as nymphs may do this in different nymphal stages (e.g. Macustus grisescens and Speudotettix subfusculus) and thus adults may be encountered throughout the growing season. This has much confused the interpretation of number of generations based on adult records of such species.