Alpi ristiku (Trifolium alpestre L.) populatsioonid Eestis: stressirikas elu levikupiiril
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Kuupäev
2017
Kättesaadav alates
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Käesolevas töös uuritakse Eestis haruldase, oma areaali põhjapiiril elava liigi - alpi ristiku
(Trifolium alpestre L.) populatsioone ning neid mõjutavaid ökoloogilisi tingimusi.
Töö eesmärgiks on välja selgitada, millised ökoloogilised tegurid piiravad alpi ristiku
levikut tema leviala põhjapiiril ja tekitavad Eestis leiduvatel populatsioonidel kõige enam
stressi.
Andmete kogumiseks uuriti kuut populatsiooni, mis asuvad Lääne-Saaremaal, Viidumäe
looduskaitsealal ning selle lähistel. Populatsioonides mõõdeti taimede kõrgus, üldkatvus,
liigirohkus ja kasvukoha valgustingimused. Igast populatsioonist võeti kakskümmend alpi
ristiku võsu, mis herbariseeriti ning mõõdeti morfoloogilised tunnused – lehtede koguarv,
õisikute arv, võsu kõrgus, leherootsude pikkus, lehelaba ning õisikute pikkus ja laius, lehe
eripind. Andmestiku koostamisel ja andmete analüüsimisel kasutati programme MS Excel
2013 ja Statistica 8 (StatSoft 2007). Seoste uurimiseks rakendati lineaarset
regressioonanalüüsi.
Töö tulemustest selgub, et kehvad valgustingimused on peamine ökoloogiline tegur, mis
piirab alpi ristiku levikut tema põhjapiiril ning tekitab kõige enam stressi. Ümbritsev
taimestik töös uuritud populatsioone oluliselt ei mõjutanud. Selgub, et kehvades
valgustingimustes on taimedel õhukesed lehed ja suur eripind. Võib väita, et valguse
puudumine pärsib ka taimede paljunemist, kuna kehvades tingimustes suunab taim oma
energia pigem valgusele eksponeerimisele kui sugulisele paljunemisele.
In this bachelor thesis the populations of rare and protected species in Estonia – purple globe clover (Trifolium alpestre L.) is studied. This species grows in Estonia on the northern edge of its distribution area, and therefore it is both scientifically interesting and from the conservational point of view important to study its ecology. The aim of this thesis is to understand which ecological factors cause the most stress to the Estonian purple globe clover’s populations on the edge of northern distribution range. What are the main limiting factors affecting the viability of its populations here. To collect the data, six populations located in Western-Saaremaa in Viidumäe Nature Reserve and around it were studied. In all the populations plant height, coverage, species abundance and light conditions of the habitat were measured. Out of every population, twenty individuals of purple globe clover were collected and herborized. Functional traits – total number of leaves and flowerheads, plant height, width of the patriole, width and length of the leaf and flowerhead and specific leaf area were measured later in the laboratory. For studying the relationships between continuous variables between different environmental factors and functional traits, linear regression analysis was used. Results show that the main limiting ecological factor, causing the most stress for purple globe clover, is insufficient light. Studied individuals weren’t significantly affected by surrounding vegetation, but by poor light conditions (indicated by thin leaves and large specific leaf area), that probably inhibits the species´ reproduction process.
In this bachelor thesis the populations of rare and protected species in Estonia – purple globe clover (Trifolium alpestre L.) is studied. This species grows in Estonia on the northern edge of its distribution area, and therefore it is both scientifically interesting and from the conservational point of view important to study its ecology. The aim of this thesis is to understand which ecological factors cause the most stress to the Estonian purple globe clover’s populations on the edge of northern distribution range. What are the main limiting factors affecting the viability of its populations here. To collect the data, six populations located in Western-Saaremaa in Viidumäe Nature Reserve and around it were studied. In all the populations plant height, coverage, species abundance and light conditions of the habitat were measured. Out of every population, twenty individuals of purple globe clover were collected and herborized. Functional traits – total number of leaves and flowerheads, plant height, width of the patriole, width and length of the leaf and flowerhead and specific leaf area were measured later in the laboratory. For studying the relationships between continuous variables between different environmental factors and functional traits, linear regression analysis was used. Results show that the main limiting ecological factor, causing the most stress for purple globe clover, is insufficient light. Studied individuals weren’t significantly affected by surrounding vegetation, but by poor light conditions (indicated by thin leaves and large specific leaf area), that probably inhibits the species´ reproduction process.
Kirjeldus
Bakalaureusetöö
Loodusvarade kasutamise ja kaitse õppekaval
Märksõnad
bakalaureusetööd, alpi ristik, levikupiirid, ökoloogilised tegurid, valgustingimused