Coppock D L, Detling J K, Ellis J E, Dyer M I
Natural Resource Ecology Laboratory, Colorado State University, 80523, Fort Collins, CO, USA.
Environmental Resources Section, Environmental Science Division, Oak Ridge National Laboratories, 37830, Oak Ridge, TN, USA.
Oecologia. 1983 Jan;56(1):1-9. doi: 10.1007/BF00378210.
Research was conducted to determine the effects of a native, sedentary rodent of North American grasslands, the black-tailed prairie dog (Cynomys ludovicianus), on seasonal aboveground plant biomass and nutrient dynamics and plant species diversity. The study was done on a northern mixed-grass prairie site at wind Cave National Park, South Dakota.Peak live plant biomass was greatest (190 g/m) on the uncolonized part of the study area and least (95 g/m) on a part of the prairie dog town colonized for 3 to 8 y. Peak live plant biomass (170 g/m) of the oldest portion of the prairie dog town (colonized >26 y) was not significantly different from that of uncolonized prairie. However, where-as graminoids composed >85% of the total biomass of the latter area, forbs and dwarf shrubs (Artemisia frigida) were >95% of the total of the former. Both standing-dead plant biomass and litter declined markedly as time since colonization increased. Total plant species diversity (H) was greatest in the young prairie dog town (colonized for 3 to 8 y).Nitrogen concentration of plant shoots varied significantly as a function of time since colonization. Shoot-nitrogen was lowest in plants from the uncolonized site and greatest in plants collected from the longest-colonized areas of the prairie dog town. Shoot-nitrogen declined significantly over the growing season and tended to be higher in C graminoids than in C graminoids. In vitro digestible dry matter showed similar trends; the differences between C and C digestibilities were greatest during the last half of the growing season.We suggest that prairie dog-induced changes in plant biomass, plant species diversity, plant nutrient content, and forage digestibility may lead to further alterations of nutrient cycling and trophic dynamics in this mixed-grass prairie ecosystem.
开展了一项研究，以确定北美草原土生土长的穴居啮齿动物——黑尾土拨鼠（Cynomys ludovicianus）对季节性地上植物生物量、养分动态和植物物种多样性的影响。该研究在南达科他州风洞国家公园的北部混合草草原地点进行。研究区域未被占据部分的活植物生物量峰值最大（190克/平方米），而在被土拨鼠占据3至8年的区域，该值最小（95克/平方米）。土拨鼠城镇最古老部分（被占据超过26年）的活植物生物量峰值（170克/平方米）与未被占据的草原无显著差异。然而，在后者区域，禾本科植物占总生物量的85%以上，而在前者区域，杂类草和矮灌木（冷蒿）占总量的95%以上。随着自被占据以来时间的增加，立枯植物生物量和凋落物均显著下降。植物物种总多样性（H）在年轻的土拨鼠城镇（被占据3至8年）最大。植物地上部分的氮浓度随自被占据以来的时间显著变化。未被占据地点的植物地上部分氮含量最低，而从土拨鼠城镇被占据时间最长区域采集的植物地上部分氮含量最高。地上部分氮在生长季节显著下降，并且C4禾本科植物中的含量往往高于C3禾本科植物。体外可消化干物质呈现类似趋势；C4和C3消化率之间的差异在生长季节后半段最大。我们认为，土拨鼠引起的植物生物量、植物物种多样性、植物养分含量和饲料消化率的变化可能会导致该混合草草原生态系统中养分循环和营养动态的进一步改变。
