疏林草原

草原生態系統
(重定向自稀树草原

疏林草原(英文: savannasavannah),又譯稀樹草原(Taíno阿拉瓦克语:sabana),是一种疏林与草原交错分布的生物群系,较森林草原更为干旱。疏林草原分为热带或亚热带的疏林莽原(常见)、温带的沙地疏林草原(较罕见)以及安第斯高山疏林草原乃至喜马拉雅的(干)热性灌草丛(极罕见)。

熱帶莽原主要分佈於非洲巴西澳大利亞的部分地區。是一種混合林地與草地的生態系統,其特徵是樹木的間距大,樹冠層不至密閉,因此有足夠的光線到達地面,可以供應完整草本植物層。[1][2][3]

澳大利亞北部的典型熱帶疏林莽原,可見樹木的高密度與規則分布等特徵。

儘管樹木密度很高,疏林莽原的樹冠層仍是開放的。[4]就字面上看來,或許會以為樹木分佈廣泛,分散,但在許多熱帶稀樹草原,與森林相比,樹木密度更高,但樹木的間距比較規則。[5][6][7][8]南美稀樹草原( cerrado sensu stricto 和 cerrado dense)的樹木密度為每公頃 800-3300 棵樹(樹/公頃),此密度與南美熱帶森林相仿或甚或更高(800- 2000 棵樹/公頃)。[5][7][8] 幾內亞稀樹草原的樹木密度為 129 棵樹/公頃,而河岸森林為 103 棵樹/公頃。[6] 澳大利亞東部稀樹草原的樹木密度,與同地區硬葉林的平均樹木密度相當(約為100 棵樹/公頃)。[9]

疏林莽原的另一個特點是水源供應的季節性:大部分降雨僅限於一個季節,經常位於森林與沙漠或草原之間的過渡地帶。不同類型的生物能適應高溫而有長乾季的環境:植物均有耐旱特性,食物資源豐富,草食性動物繁盛,有垂直分層覓食特性。長頸鹿大象食用較高層樹葉黑犀牛大羚羊食用較低矮樹和灌木,小羚羊吃最低層的樹葉,斑馬吃草類頂部,而瞪羚則啃食嫩草及草根。疏林莽原約佔地球陸地面積的 20%。[10]

分类及生态区编辑

  • 热带及亚热带稀树莽原
  • 温带稀树莽原
  • 地中海式稀树莽原
  • Flooded savannas
  • Montane savannas (高地稀樹莽原)

参考编辑

  1. ^ Anderson, Roger A., Fralish, James S. and Baskin, Jerry M. editors.1999. Savannas, Barrens, and Rock Outcrop Plant Communities of North America. Cambridge University Press.
  2. ^ McPherson, G. R. (1997). Ecology and management of North American Savannas. Tucson, AZ: University of Arizona Press.
  3. ^ Werner, Patricia A.; B. H. Walker; P. A Stott. Introduction. Patricia A. Werner (编). Savanna Ecology and Management: Australian Perspectives and Intercontinental Comparisons. Oxford: Blackwell Publishing. 1991 [2021-12-30]. ISBN 978-0-632-03199-3. (原始内容存档于2021-12-30). 
  4. ^ Alexandro Solórzano, Jeanine Maria Felfili 2008”Comparative analysis of the international terminaoolgy for cerrado” IX Symposio Nacional Cerrado 13 a 17 de outubro de 2008 Parlamundi Barsilia, DF
  5. ^ 5.0 5.1 Manoel Cláudio da Silva Jánior, Christopher William Fagg, Maria Cristina Felfili, Paulo Ernane Nogueira, Alba Valéria Rezende, and Jeanine Maria Felfili 2006 “Chapter 4. Phytogeography of Cerrado Sensu Stricto and Land System Zoning in Central Brazil” in “Neotropical Savannas and Seasonally Dry Forests: Plant Diversity, Biogeography, and Conservation” R. Toby Pennington, James A. Ratter (eds) 2006 CRC Press
  6. ^ 6.0 6.1 Abdullahi Jibrin 2013 “A Study of Variation in Physiognomic Characteristics of Guinea Savanna Vegetation” Environment and Natural Resources Research 3:2
  7. ^ 7.0 7.1 Erika L. Geiger, Sybil G. Gotsch, Gabriel Damasco, M. Haridasan, Augusto C. Franco & William A. Hoffmann 2011 “Distinct roles of savanna and forest tree species in regeneration under fire suppression in a Brazilian savanna” Journal of Vegetation Science 22
  8. ^ 8.0 8.1 Scholz, Fabian G.; Bucci, Sandra J.; Goldstein, Guillermo; Meinzer, Frederick C.; Franco, Augusto C.; Salazar, Ana. 2008 “Plant- and stand-level variation in biophysical and physiological traits along tree density gradients in the Cerrado”, Brazilian Journal of Plant Physiology
  9. ^ Tait, L 2010, Structure and dynamics of grazed woodlands in North-eastern Australia, Master of Applied Science Thesis, Central Queensland University, Faculty of Science, Engineering and Health, Rockhampton.
  10. ^ Sankaran, Mahesh; Hanan, Niall P.; Scholes, Robert J.; Ratnam, Jayashree; Augustine, David J.; Cade, Brian S.; Gignoux, Jacques; Higgins, Steven I.; Le Roux, Xavier. Determinants of woody cover in African savannas. Nature. December 2005, 438 (7069): 846–849. Bibcode:2005Natur.438..846S. ISSN 0028-0836. PMID 16341012. S2CID 4344778. doi:10.1038/nature04070 (英语). 

参见编辑