Nicolai Volker
Fachbereich Biologie/Zoologie, Philipps-Universität, D-3550, Marburg/Lahn, Federal Republic of Germany.
Oecologia. 1989 Aug;80(3):421-430. doi: 10.1007/BF00379046.
The thermal properties of 26 African tree species in two different ecosystems were studied using thermocouples. In a subtropical moist forest were three bark types of trees: species with thin and smooth bark types with low values of insulation across the bark; species with a more structured bark type and medium insulation values; and species with deep-fissured or scaly bark types and high insulation values. Only these latter trees are able to survive openings in the subtropical forest and stand alone on edges of forest gaps. In the savanna all tree species showed adaptations in the structure of their bark in different forms: many tree species shade their trunks. Some have low bark insulation and these are known to be sensitive to fires. Some tree species show high bark insulation and do not shade their trunks. Tree species with white bark avoid overheating of their surface by reflection of the radiation. The arthropod community living exclusively on the bark was investigated for the first time on South African trees, on ten tree species. In the two different ecosystems this habitat is occupied by different arthropod groups. In the subtropical forest Acari, Araneae, Opiliones, Isopoda, Myriopoda, Blattodea, Psocoptera, Heteroptera, Coleoptera, Formicidae, and Nematocera (Diptera) are the main arthropod groups living exclusively on the bark of trees. In the savanna Pseudoscorpiones, Araneae, Collembola, Blattodea, Psocoptera, Coleoptera, Neuroptera, Termites, Formicidae, Hymenoptera and Brachycera (Diptera) are the main arthropod groups living exclusively on the bark of trees. Within one ecosystem on one bark type the dominant species are similar; richly structured bark types have a richer fauna. In the forest, bark arthropod diversity is related to the bark structure of the constituent trees, and the arthropod communities on the bark would reflect changes in the structure of the forest. Forests comprising tree species with different bark types would have a richer total bark arthropod fauna. Specialists on richly structured bark types would die out if tree species composition were altered by man to give stands consisting only of tree species with smooth bark types. Bark arthropods in a subtropical moist forest have different proportions of herbivorous and fungivorous compared to carnivorous species than those on the bark of trees in a savanna.
利用热电偶对两个不同生态系统中的26种非洲树种的热特性进行了研究。在亚热带湿润森林中有三种树皮类型的树木：树皮薄且光滑、树皮隔热值低的树种；树皮结构更复杂、隔热值中等的树种；以及树皮有深裂缝或鳞片、隔热值高的树种。只有后一种树木能够在亚热带森林的林中空地存活，并独自生长在林窗边缘。在稀树草原，所有树种都以不同形式在树皮结构上表现出适应性：许多树种会遮蔽树干。一些树种的树皮隔热性低，已知它们对火灾敏感。一些树种的树皮隔热性高，且不会遮蔽树干。树皮为白色的树种通过反射辐射避免其表面过热。首次在南非的10种树的树皮上对仅生活在树皮上的节肢动物群落进行了调查。在这两个不同的生态系统中，这个栖息地被不同的节肢动物类群占据。在亚热带森林中，蜱螨目、蜘蛛纲、盲蛛目、等足目、多足纲、蜚蠊目、啮目、异翅亚目、鞘翅目、蚁科和长角亚目（双翅目）是仅生活在树皮上的主要节肢动物类群。在稀树草原，伪蝎目、蜘蛛纲、弹尾纲、蜚蠊目、啮目、鞘翅目、脉翅目、白蚁科、蚁科、膜翅目和短角亚目（双翅目）是仅生活在树皮上的主要节肢动物类群。在一个生态系统中，一种树皮类型上的优势物种相似；结构丰富的树皮类型有更丰富的动物群落。在森林中，树皮节肢动物的多样性与构成树木的树皮结构有关，树皮上的节肢动物群落会反映森林结构的变化。由具有不同树皮类型的树种组成的森林会有更丰富的树皮节肢动物总群落。如果人类改变树种组成，使林分仅由树皮光滑的树种组成，那么依赖结构丰富的树皮类型的物种将会灭绝。与稀树草原树木的树皮相比，亚热带湿润森林中树皮上的食草性和食真菌性节肢动物与食肉性节肢动物的比例不同。
