Varise lagunemine ja selgrootud lagundajad erineva vanusega salumetsades
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Kuupäev
2022
Kättesaadavus
07.09.2022
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Varise lagunemine on maismaaökosüsteemides võtmeprotsess, mis kontrollib toitainete
ringet ja selle kaudu primaarproduktsiooni. Metsakõdus ja ülemises mullakihis elavate
organismide arvukus ja taksonoomiline kuuluvus mõjutavad varise lagunemise kiirust ja
toitainete vabanemist, kuid see elustik on oluliselt mõjutatud puistute omadustest ning
keskkonnatingimustest. Lagundamisel on oluline roll mikroorganismidel ja selgrootutel.
Käesoleva töö eesmärgiks oli uurida, milline on selgrootute lagundajate koosluse koosseis
ja mikroobse lagunemise intensiivsus lageraiejärgsetes puistutes ning võrrelda neid
näitajaid vanade metsade vastavate näitajatega. Eestis on selgrootute lagundajate osa
metsavarise lagunemisprotsessis uuritud vähe. Uuringuks valitud kümme naadi
kasvukohatüüpi haaviku prooviala võimalikult sarnastes keskkonnatingimustes paiknesid
Tartumaal, Selgisel. 29.05.21-04.11.21 koguti proovialadelt varisest ja kõdust koosnevad
proovid, kust ekstraheeriti välja kõik selles leiduvad selgrootud, loendati ja määrati nende
taksonoomiline kuuluvus. Mikroobikoosluse aktiivsus ja biomass määrati oktoobrikuu
proovidest. Viidi läbi teekotikeste lagunemiseksperiment mille käigus hinnati taimse
materjali lagunemiskiirust kõdus.
Töö hüpotees, et lagunemise intensiivsus ja lagundajakoosluste taksonoomiline koosseis
on seotud puistu vanusega ning elupaiga tingimustega, leidis kinnitust, Selgus, et
erinevatel lagundajatel on erinevad eelistused puistu vanuse suhtes. Näiteks vanemates
puistutes oli kõrgem nii kõdukihi mikroobikoosluse biomass kui ka mikroobide
hingamisaktiivsus. Nende lagundajate arvukus, kes eelistasid rohttaimede varist, oli
suurem nooremates metsades ning vanemaid metsasid asustasid liigid, kes vajasid
elukeskkonnaks väljakujunenud kõdukihti. Töö tulemused võimaldavad edasisi
lagunemisdünaamika uuringuid ning lahendada metsade mulla seisundiga seotud
probleeme.
Decomposition of litter is a key process in terrestrial ecosystems that controls nutrient cycling and, through it, primary production. The abundance and taxonomic composition of decomposer communities in litter, forest floor and in the upper soil layer affect the rate of decomposition and nutrient mineralization, while biota is significantly affected by stand characteristics and environmental conditions. Microorganisms and invertebrates play an important role in decomposition. The aim of study was to investigate the composition of the invertebrate decomposers’ communities and the intensity of microbial decomposition of litter in stands after clearcutting and to compare these indicators with the corresponding indicators of older forests. There are almost no publications on the role of invertebrates in the decomposition process in Estonian forests. Ten sample areas were located in Tartu County, Selgise, in Aegopodium site type, in the similar environmental conditions. Samples of litter and forest floor were collected in 29.05.21-04.11.21, the invertebrates were extracted, counted and their taxonomic status was identified. Microbial community activity and biomass were analysed from samples collected in October. A decomposition experiment was performed by tea bag method. The hypothesis was confirmed: the rate of decomposition and the taxonomic composition of decomposer communities are related to stand age and habitat conditions. The decomposers have different preferences for stand age. For example, the biomass of the microbial community of the litter and forest floor layer and the respiration activity of the microorganisms were higher in older stands. In the younger forests the number of decomposers who preferred herbaceous plants was higher. In older forests the litter layer was inhabited by species that spend their entire lives in the litter and forest floor. The results of the current study allow further research to help assess the decomposition rate in young stands after clearcutting and to solve the problems related to the condition of the forest soils.
Decomposition of litter is a key process in terrestrial ecosystems that controls nutrient cycling and, through it, primary production. The abundance and taxonomic composition of decomposer communities in litter, forest floor and in the upper soil layer affect the rate of decomposition and nutrient mineralization, while biota is significantly affected by stand characteristics and environmental conditions. Microorganisms and invertebrates play an important role in decomposition. The aim of study was to investigate the composition of the invertebrate decomposers’ communities and the intensity of microbial decomposition of litter in stands after clearcutting and to compare these indicators with the corresponding indicators of older forests. There are almost no publications on the role of invertebrates in the decomposition process in Estonian forests. Ten sample areas were located in Tartu County, Selgise, in Aegopodium site type, in the similar environmental conditions. Samples of litter and forest floor were collected in 29.05.21-04.11.21, the invertebrates were extracted, counted and their taxonomic status was identified. Microbial community activity and biomass were analysed from samples collected in October. A decomposition experiment was performed by tea bag method. The hypothesis was confirmed: the rate of decomposition and the taxonomic composition of decomposer communities are related to stand age and habitat conditions. The decomposers have different preferences for stand age. For example, the biomass of the microbial community of the litter and forest floor layer and the respiration activity of the microorganisms were higher in older stands. In the younger forests the number of decomposers who preferred herbaceous plants was higher. In older forests the litter layer was inhabited by species that spend their entire lives in the litter and forest floor. The results of the current study allow further research to help assess the decomposition rate in young stands after clearcutting and to solve the problems related to the condition of the forest soils.
Kirjeldus
Bakalaureusetöö
Metsanduse õppekaval
Märksõnad
bakalaureusetööd, salumetsad, varise lagunemine, lagundajad, mikroobne lagunemine