Makundi Rhodes H, Massawe Apia W, Mulungu Loth S
Pest Management Center, Sokoine University of Agriculture, Morogoro, Tanzania.
Integr Zool. 2007 Dec;2(4):233-8. doi: 10.1111/j.1749-4877.2007.00063.x.
The multimammate rat, Mastomys natalensis Smith 1834, is a dominant species in agro-ecosystems in Sub-Saharan Africa, but adapts quickly to changes in non-agricultural landscape, particularly woodlands and forests. In this study we report on reproduction and population dynamics of M. natalensis in deforested high elevation localities in the Usambara Mountains, north-east Tanzania. We conducted Capture-Mark-Recapture studies in 2002-2004, and established that reproduction of M. natalensis takes place in the extended wet season between February and June, and the population density peaks in June-August. Reproduction cease in July to January and population density drops from July onwards. Reproduction and population density fluctuations are linked to the duration and amount of rainfall. In years when rainfall was below average and the wet season was short, the population density was significantly lower (below 10 animals/ha and 60 animals/ha in 2003 and 2004 respectively, compared to >100 animals/ha in 2002 when rainfall was above the seasonal average) (F(df 2,13)= 9.092, p < 0.01 for in between years variations and F(df 12,15)= 5.389, p < 0.01 for effect of cumulative annual rainfall on population density). These densities were much lower than in the lowland savannah habitats in central and southwest Tanzania. A comparison between the farmland/fallow mosaic fields and agro-forestry areas showed higher population densities in the former, which have similarities to the preferred habitats in the lowland savannahs. The increasing abundance of M. natalensis in the Usambara could have some consequences: M. natalensis is major pest and is involved in the plague cycle in the western Usambara Mountains. Mastomys natalensis is also a strong competitor and the impact on endemic rodent species, e.g. Lophuromys flavopunctatus and Praomys delectorum is unknown.
多乳鼠（Mastomys natalensis Smith，1834年）是撒哈拉以南非洲农业生态系统中的优势物种，但能迅速适应非农业景观的变化，尤其是林地和森林。在本研究中，我们报告了坦桑尼亚东北部乌桑巴拉山脉森林砍伐后的高海拔地区多乳鼠的繁殖和种群动态。我们在2002 - 2004年进行了标记重捕研究，确定多乳鼠的繁殖发生在2月至6月的延长雨季，种群密度在6月至8月达到峰值。繁殖在7月至1月停止，种群密度从7月开始下降。繁殖和种群密度波动与降雨的持续时间和降雨量有关。在降雨量低于平均水平且雨季较短的年份，种群密度显著较低（2003年和2004年分别低于10只/公顷和60只/公顷，而2002年降雨量高于季节平均水平时大于100只/公顷）（年份间变化的F(df 2,13)= 9.092，p < 0.01；累积年降雨量对种群密度影响的F(df 12,15)= 5.389，p < 0.01）。这些密度远低于坦桑尼亚中部和西南部的低地草原栖息地。农田/休耕镶嵌田和农林复合区的比较表明，前者的种群密度较高，这与低地草原的首选栖息地相似。乌桑巴拉地区多乳鼠数量的增加可能会产生一些后果：多乳鼠是主要害虫，参与了西乌桑巴拉山脉的鼠疫循环。多乳鼠也是一个强大的竞争者，其对当地啮齿动物物种，如黄斑毛鼠（Lophuromys flavopunctatus）和德氏柔毛鼠（Praomys delectorum）的影响尚不清楚。
