阿根廷淡水大米草沼泽中野生豚鼠的种群统计和微生境的利用

本文研究了秋冬季节淡水大米草(Spartina densiflora)沼泽中野生豚鼠(Cavia a perea)的丰度、繁殖和微生境利用，以及其对当地植被和棉鼠类(Sigmodontine)啮齿动物的影响。野生豚鼠喜好S.densiflora覆盖度高的生境。繁殖个体(成体)主要利用矮草为主的斑块，幼体则主要利用禾本科植物为主的斑块。结果说明，野生豚鼠微生境的利用受捕食风险和食物种类的影响。在淡水沼泽中，野生豚鼠的丰度、繁殖、体重和微生境利用没有季节性变化，它们对植物的取食和活动跑道的建造对植被结构和同域的啮齿类动物没有负面影响。通过对具有中度季节性变化的淡水生境中的豚鼠种群和具有高度季节变化的草地和路边中的豚鼠种群进行比较，表明野生豚鼠的种群动态以及豚鼠种群对植被和与其共生的啮齿动物群落的影响都受到冬季植被盖度的限制。

Demography and microhabitat use of the wild guinea pig(Cavia aperea) in freshwater Spartina densiflora marshes in Argentina

We studied abundance, reproduction and microhabitat use of the wild guinea pig (WGP), Cavia aperea, and its influence on vegetation and sigmodontine rodents during the fall-winter period in freshwater Spartina densiflora marshes. WGP preferred microhabitats with high S. densiflora cover. Reproductive individuals (=adults) mainly used patches dominated by short grasses, while juveniles used patches with forbs. These results suggest that microhabitat use in the WPG is influenced by predation risk (availability of safe foraging sites and refuges) and type of food. In freshwater marshes, WGP abundance, reproduction, body weight and microhabitat use exhibited no seasonal variations, and their herbivory and runway construction activities had no negative effect on vegetation structure and sigmodontine rodents. Results from a comparison between WGP populations living in freshwater habitats (moderate seasonality) vs grasslands and roadsides (strong seasonality), suggest that the population dynamics of the WGP, as well as the impact of the WGP population on vegetation and on coexisting rodent communities, are influenced by the availability of plant cover during winterActa Zoologica Sinica 49(1):20-31,2003].