Long-Term Effects of Grazing and Global Warming on the Composition and Carrying Capacity of Graminoid Marshes for Moulting Geese in East Greenland
Long-Term Effects of Grazing and Global Warming on the Composition and Carrying Capacity of Graminoid Marshes for Moulting Geese in East Greenland
复制标题
放牧和全球变暖对格陵兰岛东部蜕皮鹅禾本科沼泽的组成和承载能力的长期影响
作者：
J. Madsen;C. Jaspers;M. Tamstorf;C. Mortensen;F. Rigét
由于气候变暖，北极的绿化可能为食草动物提供更丰富的食物供应，导致食草动物密度增加。反过来，这可能会导致植被组成和生态系统功能的变化。1982-1984年，我们在低北极东格陵兰的詹姆森地研究了非繁殖换羽鹅的生态。到那时，鹅消耗了可用苔藓沼泽中的大部分禾本科植物，似乎鹅已经填满了可用的栖息地。2008年，我们重新访问了该地区，发现换羽鹅的数量和6月至7月的温度总和增加了两倍，而未被鹅放牧的苔藓沼泽的地上生物量增加了一倍多。在鹅放牧沼泽，整体植物组成不变，但禾本科植物的频率下降，死亡植被和开放点的面积增加。我们认为气候变暖导致了生产力的提高，允许更多的换羽鹅。然而，放牧造成的植被覆盖减少可能会对栖息地所能维持的鹅数量产生长期的负面影响。
Greening of the Arctic due to climate warming may provide herbivores with richer food supplies, resulting in higher herbivore densities. In turn, this may cause changes in vegetation composition and ecosystem function. In 1982–1984, we studied the ecology of non-breeding moulting geese in Jameson Land, low Arctic East Greenland. By then, geese consumed most of the graminoid production in available moss fens, and it appeared that the geese had filled up the available habitat. In 2008, we revisited the area and found that the number of moulting geese and the temperature sum for June–July had tripled, while the above-ground biomass in a moss fen ungrazed by geese had more than doubled. In a goose-grazed fen, the overall plant composition was unchanged, but the frequency of graminoids had decreased and the area with dead vegetation and open spots had increased. We suggest that climate warming has lead to increased productivity, allowing for higher numbers of moulting geese. However, the reduction of vegetation cover by grazing may have longer term negative consequences for the number of geese the habitat can sustain.