Abstracts Category : Other

Chronosequence studies of ecosystem development of Leymus arenarius dunes in Iceland

by Stefnsdttir 1959 Gurn

Sandhlasvi, sem hr landi eru einkum melhlar ea mellnd, eru kvik vistkerfi me stugu foki sands. Sambrileg vistkerfi er a finna um allan heim, fr hslttum meginlandanna, raurum til fjrusanda. au eru umfangsmikil slandi en hr er a finna yfir 22.000 km2 af sandaunum, allt fr fjru til mihlendisins, aan sem eldfjallaaska berst me vindi og jkulm. Melgresi (Leymus arenarius) er ein af mikilvgustu tegundunum sem rfast sandaunum hr landi. Far rannsknir eru til um framvindu mellndum slandi, srstaklega er lti um rannsknir uppsfnun lfrns efnis kringum melgresi og virkni ess neanjarar.g rannsakai framvindu, uppsfnun kolefnis og kfnunarefnis mellndum, tveimur svum:1) Surtsey, ar sem var 40 ra aldursr af melhlum sem mynduust af sjlfsum melplntum.2) Leirdal, sandslttu milli Brfells og Heklu, ar sem skufall r Heklugosum hefur endurteki eytt grri. Landgrsla rkisins hefur s melgresi ar til a hefta sku kjlfar eldgosa. ar voru valdar misgamlar sningar til a f aldursr er spannai einnig um 40 r.Uppsfnun kolefnis, bi rtarkolefnis (ROC) og jarvegskolefnis (SOC) var meiri Leirdal, en ar var rta-sprota hlutfall (R/S) og ROC/SOC samt lgra efstu 30 cm jarvegsins elstu melhlnum en Surtsey. bum rannsknarsvunum var mesta aukningin kolefnisfora vistkerfisins fyrir nean 30 cm snatkudpt. etta sndi a hin stalaa snatkudpt sem notu er landsttektum til a mla kolefnisbindingu vistkerfum hentar ekki fyrir slk melgresissvi.Mun meira kfnunarefni safnaist rlega upp melhlunum Surtsey en fellur me komu. Sennilegasta skringin er s a hinar lngu rtur melgresisins sem einnig er a finna grnum svum umhverfis hlinn hafi flutt kfnunarefni inn hlana. annig a melgresishlar Surtsey eru flug frumframvindu kerfi sem mynda bletti vistkerfinu sem gtu san ori lykilsvi (e. hot spots) fyrir frekari jarvegsmyndun og framvindu.; Sand-dunes are dynamic ecosystems with continuous disturbance that are found all over the world. In Iceland there are 22,000 km2 of sandy deserts. The Leymus arenarius is a plant species adapted to colonize and survive in areas with moving sand. It frequently forms sand-dunes where it facilitates the build-up of organic matter and soil formation. Few studies exist on the development of revegetated Leymus areas in Iceland, especially the belowground processes. To examine these, I studied two 37 and 40 yearlong chronosequences dominated by Leymus: 1) on Surtsey island, which was created in an oceanic eruption between 1963-1967, and 2) in Leirdalur, an area affected by tephra deposits from numerous eruptions in Mt. Hekla, containing areas revegetated with Leymus seeds at different times.When comparing the two study sites, where Leymus colonized naturally (Surtsey) and where it was sown (Leirdalur), it was noteworthy that the build-up of carbon stock in the soil as root organic carbon (ROC) and soil organic carbon (SOC) was much greater