Djordjević Vladan, Lakušić Dmitar, Novković Ivan, Stevanović Vladimir, Tsiftsis Spyros
Institute of Botany and Botanical Garden, Faculty of Biology, University of Belgrade, Takovska 43, 11000 Belgrade, Serbia.
Faculty of Geography, University of Belgrade, Studentski trg 3, 11000 Belgrade, Serbia.
Plants (Basel). 2025 Feb 3;14(3):443. doi: 10.3390/plants14030443.
The Balkan Peninsula is considered one of the most important centres of orchid diversity in Europe. However, the patterns of orchid species richness in the Central Balkans have not been sufficiently studied so far. The aim of this study was, therefore, to identify the centres of orchid diversity and the factors that influence the spatial variation in orchid species richness in the Central Balkans. For the analyses, the area of the Central Balkans was divided into 10 × 10 km grid cells. The environmental variables determined for each grid cell and used in the analyses were altitude, bioclimatic variables, geological substrates and habitat types. A random forest (RF) analysis was used to identify the environmental predictors most strongly associated with species richness. In addition to the total number of taxa, orchids with three belowground organ types were analysed separately: (a) rhizomatous orchids, (b) orchids with palmately lobed and fusiform tubers ("palmate tuberous orchids") and (c) orchids with spherical or ovoid tubers ("ovoid tuberous orchids"). In the Central Balkans, 54 orchid species and subspecies have been recorded, and the most important centres of diversity are the Tara, Zvijezda, Jadovnik and Zlatar Mountains and the Ovčar-Kablar Gorge. In general, two groups of grid cells with the largest number of orchid taxa, i.e., hotspots, stood out: (1) grid cells with a large altitudinal range and (2) grid cells occupied by gorges and ravines. The most important gradients influencing orchid species richness are specific habitat types and altitudinal ranges, while climatic factors and geological substrates are less important. The most important factors affecting the richness of total and rhizomatous orchids are altitudinal range and habitat types (, and forests), highlighting the important role of habitat heterogeneity. The maximum altitude, percentage of and forests and the minimum value of the mean temperature of the driest quarter are the most important factors for determining the richness of palmate tuberous orchids, whereas the percentage of xero-thermophilous habitat types (, and ) has the greatest influence on the richness of ovoid tuberous orchids. These results confirm the hypothesis concerning the origin and development of underground organs in orchids, emphasising that palmate tuberous orchids are best adapted to cold and humid habitat conditions, whereas ovoid tuberous orchids have the ability to grow in habitats with very warm and dry conditions. This study provides a good basis for better orchid conservation planning and underlines the importance of belowground strategies as a feature of orchid life history that should be considered when studying patterns of orchid diversity.
巴尔干半岛被认为是欧洲最重要的兰花多样性中心之一。然而，到目前为止，巴尔干半岛中部兰花物种丰富度的格局尚未得到充分研究。因此，本研究的目的是确定巴尔干半岛中部兰花多样性的中心以及影响兰花物种丰富度空间变化的因素。为了进行分析，将巴尔干半岛中部地区划分为10×10公里的网格单元。为每个网格单元确定并用于分析的环境变量包括海拔、生物气候变量、地质基质和栖息地类型。使用随机森林（RF）分析来确定与物种丰富度最密切相关的环境预测因子。除了分类单元总数外，还分别分析了具有三种地下器官类型的兰花：（a）根状茎兰花，（b）具有掌状叶和纺锤形块茎的兰花（“掌状块茎兰花”），以及（c）具有球形或卵形块茎的兰花（“卵形块茎兰花”）。在巴尔干半岛中部，已记录到54种兰花物种和亚种，最重要的多样性中心是塔拉山、兹维耶兹达山、亚多夫尼克山和兹拉塔尔山以及奥夫恰尔 - 卡布拉尔峡谷。总体而言，两组兰花分类单元数量最多的网格单元，即热点地区，脱颖而出：（1）海拔范围大的网格单元和（2）被峡谷和沟壑占据的网格单元。影响兰花物种丰富度的最重要梯度是特定的栖息地类型和海拔范围，而气候因素和地质基质的重要性较低。影响总兰花和根状茎兰花丰富度的最重要因素是海拔范围和栖息地类型（落叶林和混交林），突出了栖息地异质性的重要作用。最高海拔、落叶林和混交林的百分比以及最干燥季度平均温度最小值是决定掌状块茎兰花丰富度的最重要因素，而旱生栖息地类型（草原、灌丛和石南灌丛）的百分比对卵形块茎兰花的丰富度影响最大。这些结果证实了关于兰花地下器官起源和发育的假设，强调掌状块茎兰花最适应寒冷潮湿的栖息地条件，而卵形块茎兰花有能力在非常温暖干燥的栖息地生长。本研究为更好地进行兰花保护规划提供了良好基础，并强调了地下策略作为兰花生活史特征的重要性，在研究兰花多样性模式时应予以考虑。
