LiDARi andmete kasutamine hindamaks kuivendamise mõjusid Soosaare raba taimkatte kõrgusele
Laen...
Kuupäev
2020
Kättesaadavus
25.08.2020
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Eestis alustati turbalade kuivendamist kaua aega tagasi ning tehakse seda ka siiani, kuid
tegelikult on rabad tähtsad ökosüsteemid mida tuleks hoida ning taastada. Tänapäeval
on loodud juba mitmeid projekte ja võetut erinevaid kohti kaitse alla, et neid rohkem
enam muuta ei saaks. Soosaare soo uuele turbakaevandustele on tehtud ka
keskkonnamõju hindamine, kuid hindamisel selgus, et kuivenduskraavid ei avalda
olulist mõju Natura võrgustikule. Käesoleva bakalaureusetöö eesmärgiks on teada saada
kui kaugele ulatub kuivenduskraavi mõju raba taimkatte kõrgusele uuritaval alal 1 ning
uuritaval alal 2 teada saada, kuidas kraavituse suuna ja turbakaevandamise tehnoloogia
(freesturbaväli, pätsturbaväli) mõjub taimkatte kasvu kiirusele. Töös kasutati Maa-ameti
LiDAR andmete põhjal loodud neljast erinevast aastast pärit taimkatte kõrgusmudeleid.
Uurimisalal 1 võrreldi omavahel nelja erinevat aastat (2008-2011; 2014; 2017; 2019)
ning analüüsiti keskmise kõrgust ja standarthälvet. Uurimisalal 2 tehti kolm plokki: 1.
plokis on kraavitatusse suund piki rabarinnakut, 2. ja 3. plokis ristirabarinnakut ja 1.
plokk on rabarinnakust kaugemal. Mõlemad alad kuuluvad ka Natura 2000 võrgustikku.
Tulemustes selgus, et kuivenduskraavi (uurimisala 1) tugev mõju kestab umbes 0-30 m
ning taimkate kasvab kiiresti. Kraavi mõju kestab 60-70 meetrini ning mõju hakkab
kaduma umbes 170 m juures. Teises uurimisalas selgus, et kraavituse suuna mõju ei saa
uurida, kuna ajaline periood on lühike ning pätsturbaväljal kasvab taimkate paremini,
kuna turvast kaevandatakse aukudena ja turbavõtu aukude vahele tervikud, kus puud
saavad paremini kasvada (veetase on madalam ja mineraliseerumine kiirem ja selle
käigus vabanevad toitained).
In Estonia, drainage of peatlands started a long time ago and is still done, but in reality bogs are important ecosystems that should be preserved and restored. Today, a number of projects have already been set up and various sites taken under protection so that they can no longer be changed. An environmental impact assessment has also been carried out for the new peat mines in the Soosaare bog, but the assessment revealed that the drainage ditches do not have a significant impact on the Natura network. The aim of this bachelor's thesis is to find out how far the effect of drainage ditch on bog vegetation height in study area 1 and study area 2 is to find out how ditch direction and peat extraction technology (milling peat field, peat peat field) affect vegetation growth rate. The work used vegetation height models from four different years created on the basis of the Land Board's LiDAR data. In Study Area 1, four different years were compared (2008-2011; 2014; 2017; 2019) and the mean height and standard deviation were analyzed. Three blocks were made in the study area 2: in block 1 the direction of trenching is along the bog fortress, in blocks 2 and 3 there is a crosshair fortress and in the 1st block is farther from the bog fortress. Both sites are also part of the Natura 2000 network. The results showed that the strong effect of the drainage ditch (research area 1) lasts about 0-30 m and the vegetation grows rapidly. The effect of the ditch lasts for 60-70 m and the effect begins to disappear at about 170 m. The second study revealed that the effect of ditch direction cannot be studied because the time period is short and vegetation grows better in the peat field, because peat is mined as holes and between peat extraction holes where trees can grow better (water level is lower and mineralization is faster and nutrients are released).
In Estonia, drainage of peatlands started a long time ago and is still done, but in reality bogs are important ecosystems that should be preserved and restored. Today, a number of projects have already been set up and various sites taken under protection so that they can no longer be changed. An environmental impact assessment has also been carried out for the new peat mines in the Soosaare bog, but the assessment revealed that the drainage ditches do not have a significant impact on the Natura network. The aim of this bachelor's thesis is to find out how far the effect of drainage ditch on bog vegetation height in study area 1 and study area 2 is to find out how ditch direction and peat extraction technology (milling peat field, peat peat field) affect vegetation growth rate. The work used vegetation height models from four different years created on the basis of the Land Board's LiDAR data. In Study Area 1, four different years were compared (2008-2011; 2014; 2017; 2019) and the mean height and standard deviation were analyzed. Three blocks were made in the study area 2: in block 1 the direction of trenching is along the bog fortress, in blocks 2 and 3 there is a crosshair fortress and in the 1st block is farther from the bog fortress. Both sites are also part of the Natura 2000 network. The results showed that the strong effect of the drainage ditch (research area 1) lasts about 0-30 m and the vegetation grows rapidly. The effect of the ditch lasts for 60-70 m and the effect begins to disappear at about 170 m. The second study revealed that the effect of ditch direction cannot be studied because the time period is short and vegetation grows better in the peat field, because peat is mined as holes and between peat extraction holes where trees can grow better (water level is lower and mineralization is faster and nutrients are released).
Kirjeldus
Bakalaureusetöö
Keskkonnakaitse õppekaval
Märksõnad
bakalaureusetööd, LiDAR, kuivendamine, rabad, Soosaare raba, taimkatte kõrgus