Icelandic Inland Wetlands: Characteristics and Extent of Draining

Iceland has inland wetland areas with soils exhibiting both Andosol and Histosol properties which are uncommon elsewhere on Earth. They are generally fertile, with higher bird-nest densities than in similar wetlands in the neighboring countries, with nutrients released by rapid weathering of aeolian materials of basaltic nature. Icelandic inland wetlands cover about 9000 km2 constituting 19.4 % of the vegetated surfaces of the island. The wetland soils are often 1–3 m thick and store 33 to >100 kg C m−2. They have been subjected to broad-scale subsidy-driven draining for agricultural purposes. About 47 % of Icelandic inland wetlands are impacted by drainage. The ditch network extends about 30,000 km, mainly in lowland areas, where about 70 % of the wetland areas are impacted. There are >1 million wetland patches, most of them <1 ha. Much of the wetlands impacted from drainage are not used for intensive agriculture such as haymaking, however some are used for grazing. There is a need to prioritize the protection of undrained wetlands and their restoration based on a broad range of factors.Peer Reviewe

Interacting effects of agriculture and landscape on breeding wader populations

The capacity of different landscapes to sustain viable populations depends on the spatial and temporal availability of key population-specific resources. Heterogeneous landscapes provide a wider range of resources and often sustain higher levels of biodiversity than homogeneous ones. Across the globe, agricultural expansion has resulted in large-scale homogenisation of landscapes with associated declines in many taxa. However, during the early stages of agricultural development, in terms of area and intensity, increased landscape heterogeneity and changes in local productivity through fertilizer inputs can potentially increase resource availability for some species. Agriculture in Iceland is currently neither highly intensive nor extensive, and primarily occurs as hayfields (>90% of agricultural land) embedded within a mosaic of semi-natural wetlands and heaths. These landscapes support internationally important breeding populations of several wader species but the role of agricultural land in promoting or constraining breeding wader densities is currently unknown. Understanding the relationship between cultivation and wader populations is important as the area of cultivated land is predicted to expand in Iceland in near future, largely through conversion of the remaining semi-natural wetlands. Here we (a) quantify relationships between breeding wader densities in lowland Iceland and the amount of cultivated land and wetland in the surrounding landscape using density estimates from 200 transects in common semi-natural habitats, (b) assess the extent to which cultivated land affects wader densities in these landscapes, and the potential effects of future agricultural expansion at the expense of wetlands on wader populations. Wader densities in semi-natural habitats were consistently greater when surrounding landscapes had more wetland at scales ranging from 500 m to 2500 m, indicating the importance of wetland availability. However, the effects of cultivated land in the surrounding landscape varied with altitude (ranging from 0 to 200 m); in low-lying coastal areas, wader numbers decline with increasing amounts of cultivated land (and the lowest densities (100 m a.s.l., where lowest densities occur in areas without cultivated land). This suggests that additional resources provided by cultivated land may be more important in the less fertile uplands. Further agricultural conversion of wetlands in low-lying areas of Iceland is likely to be detrimental for breeding waders, but such effects may be less apparent at higher altitudes

Samþætting á ræktun orkuplantna og landgræðslu: greining með landfræðilegum upplýsingakerfum

Þessi lokaritgerð er skrifuð til BS. prófs við Landbúnaðarháskóla Íslands árið 2009. Gerð var LUK (landupplýsingakerfi) greining sem náði yfir allt landið í þeim tilgangi að afmarka þau svæði sem hentað gætu til ræktunar orkuplantna með landgræðlusjónarmið að leiðarljósi. Tilgangurinn með því er svo framleiðsla á metan sem orkugjafa. Takmarkaðist greiningin við hálfgróin og líttggróin svæði úr yfirborðsflokkun Nytjalands. Þau svæði þekja um 43% af heildarflatarmáli landsins. Fjölmargir þættir takmarka ræktun af þessu tagi og studdist greiningin alfarið við fyrirliggjandi landupplýsingagögn; hæð yfir sjávarmál, strandlínu, veghelgunarsvæði, skóglendi og kjarr, halla lands, hraun, friðuð svæði og manngerð svæði. Niðurstaðan er sú að um 2000km2 eða 2% af flatarmáli landsins megi nýta til samþættingar á ræktun orkuplantna og landgræðslu

Nytjaland

Nytjalandsverkefnið miðar að því að gera gagnagrunn með upplýsingum um bújarðir landsins, m.a. m.t.t. landkosta. Viðamestu verkþættirnir voru að afla upplýsinga um gróðurfar og landamerki bújarða. Upplýsingaöflun um gróðurfar miðaði að flokka svæði á grundvelli þess hversu gróskumikil þau væru sem jafnframt gæfi upplýsingar um um ástand lands og beitargildi þess. Upplýsingaöflunin náði til alls landsins, en hún var að mestu gerð með greiningum og flokkun á gervitunglamyndum með fjarkönnunaraðferðum (Remote Sensing). Til stóð að birta gögnin í stafrænni Jarðabók þar sem unnt væri að gera fyrirspurn varðandi bújarðir og fá þar upplýsingar um flest það sem viðkemur jarðareignum. Verkefninu var ekki lokið eins og fyrirhugað var, en rétt þótti að taka saman upplýsingar um það sem gert var. Í þessu riti er gerð grein fyrir aðferðafræðinni við yfirborðsflokkunina og helstu niðurstöðum. Gerð er grein fyrir bakgrunni verkefnisins, hvaða gögn liggja að baki, hvaða aðferðum var beitt og afrakstrinum. Yfirborðsflokkunin var unnin með tveimur kortlagningarlyklum sem hafa verið samþættir og mynda þannig heildarþekju yfirborðsflokkunar fyrir landið allt. Gögnin hafa verið leiðrétt m.t.t. vatnsyfirborðs eins og það er dregið upp í kortagrunni Landmælinga Íslands og einnig hefur upplýsingum um ræktað land og skóglendi verið bætt í flokkunina. Gerð er grein fyrir því hversu rétt yfirborðsflokkunnin er. Sé aðeins horft til eins af þeim stuðlum sem notaðir eru til að meta hversu vel hefur tekist til með flokkun þá sýnir gæða mat á einstökum myndum sem greindar voru í 12 yfirborðsflokka, að nákvæmni flokkunarinnar var að meðaltali 70%. Þegar öll flokkuðu gögnin höfðu verið samræmd og ýmsum aðfengnum gögnum verið bætt inn, reyndist Nytjalandsmynd með 12 flokkum vera 68% rétt en Nytjalands mynd með 8 flokkum 76% rétt. Gæðaúttektin sýndi að það sem dregur stuðla þessa niður er fyrst og fremst skörun milli flokka sem eru vistfræðilega líkir og hafa ekki skýr mörk í náttúrunni og er árangur sæmilega ásættanlegur miðað við notkun gagnanna til að fá yfirlit um grósku landsins. Gróskumestu yfirborðsflokkarnir, ræktað land, graslendi, ríkt mólendi, hálfdeigja, votlendi og skóglendi þekja samtals 16 596 km2 lands samkvæmt Nytjalandi. Rýrt mólendi og mosavaxið land er samtals 28 210 km2. Rýrt mólendi og mosavaxið land er ekki uppskerumikið og gróðurþekjan allvíða rofin, en gróður þekur þó í öllum tilvikum meira en helming yfirborðsins. Samtals er gróið land með meira en 50% gróðurþekju í Nytjalandsgögnunum 45 691 km2 eða tæplega 45% landsins.The Agricultural University of Iceland has produced a GIS database with vegetation classification map with relatively good resolution, the so-called Nytjaland database (AUI Icelandic Farmland Database). It is aimed to reflect the productivity and land use properties (i.e. for grazing) of the Icelandic vegetation. The AUI Farmland Database land cover (Nytjaland) was created based on supervised classification of satellite images. The project was initated around 2000 but was mostly halted around 2008 due to finance constraints. It uses 10 classes for vegetation in addition to glaciers/snow and open water The classification used available multispectral satellite coverage, including Landsat 7 and SPOT 4 and 5. The report describes the classification methods in some detail, but an English version if this text will be published later. It also describes the main problems with this classification, including the high diversity within classes, boundary problems (between vegetation classes and on the ground). Water information was obtained from the National Land Survey of Iceland, and forest information from the Icelandic Forest Service. Some information about agricultural land has been digitized into the database. The classification is based on 12 100 control points on the ground and it was verified by 6550 verification points. Accuracy (Error Matrix) was about 70%, but much of the mismatch was due to unclear differences between ecologically similar classes, making this level of accuracy acceptable for the purposes of the system. These similar classes include grasslands and agricultural land (hay-fields), poor heathland and half vegetated land, the heathland classes and so on. Only 70% of Iceland was covered with this classification (termed Nytjaland N12), but the remaining part of the Iceland (mostly highlands) were classified into fewer categories (Nytjaland N6) and an upgraded version (N8) has subsequently been developed with 76% accuracy. The Nytjaland project shows that 45 691 km2 of Iceland is vegetated land with >50% cover, with poor heathland being the most abundant vegetation class