Fungal targets and tools for forest conservation
Date
2016-06-20
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Abstract
Mets on seentele oluline elupaik – ning seened täidavad metsaökosüsteemis olulisi funktsioone. Valdav osa metsi on tänapäeval inimmõju tõttu vaesunud, näiteks on neis mitmekordselt vähenenud kõdupuidu ja põlispuude hulk. Niisuguseid «jäänukstruktuure» asustavad aga mitmed metsaseened; neid seeni minu doktoritöö käsitleski. Põhifookus oli metsas lagundajatena olulistel torikseentel, kuid uurisin ka puukoorel ja paljandunud puidul elavaid lihheniseerunud seeni. Peale selle, et mitmed neist seentest on ohustatud ja kaitse all, kasutatakse neid looduskaitses ka indikaatoritena teiste metsaväärtuste tuvastamisel. Töö põhieesmärgiks oli hinnata erinevate kasutatavate metsakaitse ja –majandusmeetodite olulisust seeneliikide kaitsel. Torikseente uurimisel olid põhimeetodiks viljakehadel põhinevad liigi-inventuurid. Leidsin, et puistu mastaabis on see adekvaatne meetod, sest ehkki puiduproovidest määratud DNA põhjal võivad konkreetses puutüves mütseelina elavad seened viljakehana tuvastamata jääda, on suur tõenäolisus leida sama liigi viljakeha mõnelt teiselt puutüvelt läheduses. Võrreldes torikseente levikumustreid põlismetsades, küpsetes majandusmetsades ja raiesmikel leidsin, et erinevalt Fennoskandiast, kus majandusmetsad on ulatuslikult vaesunud, ei olene Eestis enamik liike otseselt põlismetsadest. Seega lähtuvad liigi elupaigaseosed ja indikaatorväärtus piirkonna metsamaastiku üldseisundist. Üksikute liikide koondumine põlismetsa oli põhiliselt tingitud spetsiifilisest substraadivajadusest (nt suured lamakuused). Selgus ka, et liigi elupaigaseoste mõistmist võivad segada «krüptilised liigid»: sarnase välimuse taha peituvad erineva ökoloogiaga liigid, mida tuleks seente puhul tuvastada molekulaarselt. Rohkete indikaatorliikide asemel tuleks seetõttu lähtuda pigem vähestest hästi uuritud suunisliikidest. Doktoritöö näitas, et enamik kõdupuitu ja põlispuid asustavaid seeni (sh mitmed põlismetsaseoseliseks peetud liigid) saavad elada ka majandusmetsades, kui need on piisavalt vanad, seal leidub erinevaid puuliike ning piisavalt erinevaid jäänukstruktuure, sh nii erinevate puuliikide tüügas- ja lamapuid kui põlispuid. Seetõttu leidub metsamajanduse ning seente elurikkuse edukaks kombineerimiseks mitmeid võimalusi.
Forests provide habitat for a huge variety of fungi that, in turn, play key roles in several forest ecosystem processes. The fungal biota is increasingly affected by human-caused transformation of forests, i.a., significant declines in the amount of coarse dead wood and large old trees. My thesis concentrates on fungi inhabiting such structures. My main focus is on polypores that belong to the dominant dead-wood composers in the forests, but I also explore lichenised fungi. Many polypores and lichens are nowadays found mainly in the remaining old-forest patches, and the occurrence of several species is thought to indicate ecological value of a forest. My general aim was to assess the forest conservation and management practices from the perspective of the fungi inhabiting dead wood and old living trees. The main method in polypore studies was fruit-body based species-inventory. In the stand scale, I found this method efficient: while all polypore species inhabiting a tree-trunk (as revealed by their DNA in the wood samples) may not produce fruit-body on the same tree, conspecific fruit-bodies can be usually found on other trunks in close vicinity. Differently from the intensively managed Fennoscandia, the old-forest associations of polypores were relatively weak in Estonia, as revealed by a comparison of old-growth, mature managed and harvested forests. Thus, fungal habitat associations and indicator value depend on regional landscape context. For the few species that were confined to old -growths, specific substrate requirements (notably large spruce trunks) were the reason. I also show that interpreting species habitat associations may me confused by “cryptic species” that have similar morphology, but differ by genetics and ecology. Thus, conservation practices might benefit from fewer, but better supported, fungal indicators. I demonstrate that fungi inhabiting dead wood and old living trees (including putative old-forest specialists) may form species-rich assemblages also in managed forests. This is possible if these forests are diverse in terms of tree species, dead-wood structures, and successional stages, including old stands. My general conclusion is that there are many possibilities for adjusting forest management to better address the fungal diversity that depends on dead wood and old living trees.
Forests provide habitat for a huge variety of fungi that, in turn, play key roles in several forest ecosystem processes. The fungal biota is increasingly affected by human-caused transformation of forests, i.a., significant declines in the amount of coarse dead wood and large old trees. My thesis concentrates on fungi inhabiting such structures. My main focus is on polypores that belong to the dominant dead-wood composers in the forests, but I also explore lichenised fungi. Many polypores and lichens are nowadays found mainly in the remaining old-forest patches, and the occurrence of several species is thought to indicate ecological value of a forest. My general aim was to assess the forest conservation and management practices from the perspective of the fungi inhabiting dead wood and old living trees. The main method in polypore studies was fruit-body based species-inventory. In the stand scale, I found this method efficient: while all polypore species inhabiting a tree-trunk (as revealed by their DNA in the wood samples) may not produce fruit-body on the same tree, conspecific fruit-bodies can be usually found on other trunks in close vicinity. Differently from the intensively managed Fennoscandia, the old-forest associations of polypores were relatively weak in Estonia, as revealed by a comparison of old-growth, mature managed and harvested forests. Thus, fungal habitat associations and indicator value depend on regional landscape context. For the few species that were confined to old -growths, specific substrate requirements (notably large spruce trunks) were the reason. I also show that interpreting species habitat associations may me confused by “cryptic species” that have similar morphology, but differ by genetics and ecology. Thus, conservation practices might benefit from fewer, but better supported, fungal indicators. I demonstrate that fungi inhabiting dead wood and old living trees (including putative old-forest specialists) may form species-rich assemblages also in managed forests. This is possible if these forests are diverse in terms of tree species, dead-wood structures, and successional stages, including old stands. My general conclusion is that there are many possibilities for adjusting forest management to better address the fungal diversity that depends on dead wood and old living trees.
Description
Väitekirja elektrooniline versioon ei sisalda publikatsioone.
Keywords
seened, bioloogiline mitmekesisus, metsad, metsakõdu, looduskaitse, Fungi, biodiversity, forests, forest decay, nature preservation