Ecole Doctorale Ecosystèmes Naturels (EDEN), University of Mahajanga, Mahajanga, Madagascar.
Institute of Zoology, University of Veterinary Medicine Hannover, Buenteweg 17, 30559, Hannover, Germany.
BMC Ecol. 2020 Dec 17;20(1):69. doi: 10.1186/s12898-020-00337-z.
Edge effects can influence species composition and community structure as a result of changes in microenvironment and edaphic variables. We investigated effects of habitat edges on vegetation structure, abundance and body mass of one vulnerable Microcebus species in northwestern Madagascar. We trapped mouse lemurs along four 1000-m transects (total of 2424 trap nights) that ran perpendicular to the forest edge. We installed 16 pairs of 20 m vegetation plots along each transect and measured nine vegetation parameters. To determine the responses of the vegetation and animals to an increasing distance to the edge, we tested the fit of four alternative mathematical functions (linear, power, logistic and unimodal) to the data and derived the depth of edge influence (DEI) for all parameters.
Logistic and unimodal functions best explained edge responses of vegetation parameters, and the logistic function performed best for abundance and body mass of M. ravelobensis. The DEI varied between 50 m (no. of seedlings, no. of liana, dbh of large trees [dbh ≥ 10 cm]) and 460 m (tree height of large trees) for the vegetation parameters, whereas it was 340 m for M. ravelobensis abundance and 390 m for body mass, corresponding best to the DEI of small tree [dbh < 10 cm] density (360 m). Small trees were significantly taller and the density of seedlings was higher in the interior than in the edge habitat. However, there was no significant difference in M. ravelobensis abundance and body mass between interior and edge habitats, suggesting that M. ravelobensis did not show a strong edge response in the study region. Finally, regression analyses revealed three negative (species abundance and three vegetation parameters) and two positive relationships (body mass and two vegetation parameters), suggesting an impact of vegetation structure on M. ravelobensis which may be partly independent of edge effects.
A comparison of our results with previous findings reveals that edge effects are variable in space in a small nocturnal primate from Madagascar. Such an ecological plasticity could be extremely relevant for mitigating species responses to habitat loss and anthropogenic disturbances.
由于微环境和土壤变量的变化，边缘效应对物种组成和群落结构有影响。我们调查了栖息地边缘对马达加斯加西北部一种脆弱的小狐猴物种的植被结构、丰度和体重的影响。我们沿着四条垂直于森林边缘的 1000 米长的样带（共 2424 个陷阱夜）捕捉了鼠狐猴。我们在每个样带上安装了 16 对 20 米的植被样方，并测量了九个植被参数。为了确定植被和动物对距离边缘增加的反应，我们测试了四个替代数学函数（线性、幂、逻辑和单峰）对数据的拟合程度，并为所有参数推导了边缘影响深度（DEI）。
逻辑和单峰函数最好地解释了植被参数的边缘响应，逻辑函数对 M.ravelobensis 的丰度和体重表现最好。DEI 变化范围为 50 米（幼苗数量、藤本植物数量、大树胸径[胸径≥10 厘米]）到 460 米（大树树高），而 M.ravelobensis 的丰度为 340 米，体重为 390 米，与小树[胸径<10 厘米]密度的 DEI 最为接近（360 米）。与边缘栖息地相比，内部栖息地的小树明显更高，幼苗密度更高。然而，内部和边缘栖息地之间的 M.ravelobensis 丰度和体重没有显著差异，这表明 M.ravelobensis 在研究区域没有表现出强烈的边缘反应。最后，回归分析显示有三个负相关（物种丰度和三个植被参数）和两个正相关（体重和两个植被参数），这表明植被结构对 M.ravelobensis 有影响，这种影响可能部分独立于边缘效应。
将我们的结果与以前的研究结果进行比较表明，在马达加斯加的一种小型夜间灵长类动物中，边缘效应在空间上是可变的。这种生态弹性对于减轻物种对栖息地丧失和人为干扰的反应可能是极其重要的。
