Change of herb layer in the dry mesic pine forests after surface forest fire: the first year

Pētījumi par skrejuguns ietekmi uz mezofīto priežu mežu zemsedzes sugu sastāvu veikti 2015. gadā zinātniskās izpētes mežos Rucavā. Pirmajā gadā pēc meždegām priežu audzē no jauna ir konstatētas divas kserofītu augteņu sugas – Calluna vulgaris un Vicia cassubica, kā arī vairākas no jauna ieviesušās ruderālas dzīves stratēģijas sugas – Taraxacum officinale, Senecio sylvaticus un Chamaenerion angustifolium. Uguns skartajā mežaudzes daļā ievērojami ir samazinājies valdošo sīkkrūmu sugu – Vaccinium myrtillus un Vaccinium vitis-idaea daudzums un augstums, tāpat nozīmīgi ir samazinājusies boreālo mežu sūnu – Pleurozium schreberi, Hylocomium splendens un Ptilium cristacastrensis sastopamība. Kopumā pēc meždegām zemsedzes lakstaugu stāvs ir kļuvis augstāks, raksturīgo aspektu vasaras otrajā pusē lakstaugu stāvā nosaka dominējošā Deschampsia flexuosa. The article summarizes the data from the effect of surface forest fire to species quantitative and qualitative composition in dry mesic pine forest herb layer. In total, two square-shaped plots of size 30 × 30 m were established, from which one was located in forest stand affected by fire one year ago and the other one in the forest stand untouched by fire. The distance between the margins of the plots was 5 m. Both plots were located in the same forest stand. Each plot was divided into sub-plots of size 3 × 3 m. The quantity of vascular plants and bryophytes was determined in each sub-plot. The species projective cover and quantity of individuals were counted using the three point system, respectively, 1 – the quantity of species individuals was less than 1 %, 2 – the quantity of species was rom 1–25 %, 3 – the quantity of species was more than 25 %. Additionally, the point square method was used in each plot to determine the stratified cover of herbaceous and dwarf shrub species. The plots 0.50 × 0.50 m were established. The first year results showed that two xerophyte species– Calluna vulgaris and Vicia cassubica were recorded in the sample plot recently affected by fire. During the last years, none of these species have not been noted in species composition of the studied forest stand. Additionally, several species with ruderal life strategy were listed for the first time – Taraxacum officinale, Senecio sylvaticus and Chamaenerion angustifolium. The quantity and height of dominant dwarf shrub species Vaccinium myrtillis decreased in fire-affected sample plot. In the sample plot affected by fire, also the occurrence