Ecology of an Invasive Lupine

• Other Authors: Luscuskie, Lauren P. (authoraut), Department of Biological Science
• Format: Text
• Language: English
• Subjects: Biology; Iceland
• Online Access: http://purl.flvc.org/fsu/fd/FSU_migr_uhm-0481; http://fsu.digital.flvc.org/islandora/object/fsu%3A271000/datastream/TN/view/Ecology%20of%20an%20Invasive%20Lupine.jpg

Since humans began settling in Iceland, the native vegetation has been slowly degrading. Today, Iceland is one of the most heavily environmentally damaged countries due to human impacts. When Iceland was settled, approximately 60% of the land area was vegetated (Arnalds, 2001). Even as recently as two centuries ago, the plant cover of Iceland was far more extensive than it is at the present. Today, vegetation cover is estimated at 25% of the land area, with trees occupying only 1% (Arnalds, Aradóttir and Thorsteinsson, 1987; Arnalds, 2004). There are many factors that combine to affect the degradation of Iceland’s vegetated areas. The soils are derived from volcanic activity, are mostly classified as andisols, and are very inclined to erosion (Arnalds, 2004; Ólafsdóttir, Schlyter and Haraldsson, 2001). The cold, windy conditions accelerate soil erosion when plant cover is initially removed by human activity, decreasing the likelihood that vegetative cover can be re-established. The cold, wet soils experience regular frosts that further inhibit the ability of plants to colonize and re-establish themselves. Lupinus nootkatensis, the Nootka Lupine, is native to Western North America. This species of lupine has been shown to ameliorate soil characteristics in other locations due to its ability to fix nitrogen and grow in dense monocultures, subsequently influencing successional dynamics. A legume, the Nootka Lupine fixes nitrogen by a symbiosis with a rhizobium bacteria. This facilitates lupine growth in nitrogen-deficient and highly disturbed soils, such as those of volcanic origin present in Iceland (Riege and Sigurgeirsson, 2009; Myrold and Huss-Danell, 2003). In fixing nitrogen, lupine also supplements the surrounding soil with excess nitrogen. Dense monocultures of lupine, as tall as 120cm, increase litter production and decomposition as well as the trapping of detritus, increasing soil organic matter content (Myrold and Huss-Danell, 2003). Both of these methods allow lupine to improve soil characteristics in unvegetated areas, over time increasing nitrogen and organic matter content in the soils to allow for growth of native successional plant species.--Introduction. Lupinus nootkatensis, lupine, Nootka Lupine, Invasive Lupine, Iceland A Thesis submitted to the Department of Biological Science in partial fulfillment of the requirements for graduation with Honors in the Major.