Effects of Kangaroo Rat Mounds on Seed Banks of Grass and Shrublands at the Sevilleta National Wildlife Refuge, New Mexico (2001)

Disturbance is a major factor in determining the spatial structure and temporal dynamics of ecological systems. Many studies have been conducted concerning the plant assemblages around Dipodmys spectabilis mounds compared to the off mound area. These studies have shown that annual plant cover is higher on the kangaroo rat mound compared to off the mound. However, no studies have addressed the effects of these rodents disturbance on the soil seed bank. Soil seed banks are an important component of the plant community particularly in arid environments. Annual plants have been known to create viable seeds that remain dormant in the soil for many years making their seed bank a persistent one. A persistent seed bank allows for future recruitment of plants given favorable conditions that could have a dramatic impact on the overall species diversity of the community. We studied the seed bank of eight forb taxa to ask the following questions: 1) Are there more seeds in the seed bank around kangaroo rat mounds compared to other microhabitats? 2) Does the seed composition differ among the different microhabitats? 3) If the seed composition does differ, do specific physical components of microhabitats predict seed populations?干扰是调控生态系统空间结构与时间动态的关键因子。过往已有诸多研究对比了壮丽更格卢鼠（Dipodmys spectabilis）土丘周边与丘间区域的植物群落组成，结果显示相较于丘间生境，更格卢鼠土丘上的一年生植物盖度更高。然而目前尚无研究探讨此类啮齿动物的干扰对土壤种子库的影响。土壤种子库是植物群落的重要组成部分，在干旱生境中尤为关键。已知一年生植物可产生可存活的种子，这些种子会在土壤中休眠多年，进而形成持久性种子库；当环境条件适宜时，持久性种子库可支持植物后续的自然更新，这对群落整体物种多样性具有显著影响。本研究针对8种非禾本科草本类群的种子库展开调查，旨在解答以下三个问题：1. 更格卢鼠土丘周边的种子库种子数量是否多于其他微生境？2. 不同微生境的种子组成是否存在差异？3. 若种子组成确实存在差异，微生境的特定物理特征能否预测种子种群的分布？