Phytogeographical affinities at the crossroads of two continents: Distribution patterns of Lamiaceae in Chios Island (East Aegean Islands, Greece) and Çeşme–Karaburun Peninsula (West Anatolia, Turkey)

The East Aegean (East Aegean Islands, Greece and West Anatolia, Turkey) is a biogeographically transitional region, where biodiversity elements from Europe and Asia join. However, affinities in the region were until recently scarcely explored. We assess biogeographical affinities in the East Aegean focusing on distribution patterns of Lamiaceae plants in Chios Island and its adjacent Çeşme–Karaburun Peninsula. Detailed <i>in-situ</i> record was acquired for 48 native species. These were grouped based on their habitat and geological substrate preference, their distribution was mapped in grid cells and distribution patterns were analysed in relation to species groupings. In both Chios and Çeşme–Karaburun, species follow five distribution patterns: widespread, locally widespread, locally restricted, sporadic and rare. Fifty to 62% of the species exhibit similar distribution patterns, trends in habitat and geological substrate preference in Chios and Çeşme–Karaburun, results complying with previous evidence of close biogeographical affinities of the East Aegean Islands and neighbouring Anatolia. Differences observed between the two regions may be attributed to insularity effects, human impact and the melange, an old rock matrix known for its key role in elucidating regional geodynamic evolution. Distributions of widespread and locally widespread species in Chios give evidence of density compensation and niche shifts responses, however, the actual occurrence of these phenomena in island plant populations is still to be elucidated. Overall, the species distribution patterns, particularly those of rare ones, reflect the complex geological history, palaeogeography and human influence in the Aegean region.

东爱琴海区域（希腊东爱琴海群岛、土耳其安纳托利亚西部）属于生物地理过渡地带，汇聚了源自欧洲与亚洲的生物多样性类群。然而直至近期，该区域的生物地理亲缘关系仍鲜有研究。本研究聚焦希俄斯岛及其邻近的切什梅-卡拉布伦半岛的唇形科（Lamiaceae）植物分布格局，对东爱琴海区域的生物地理亲缘关系展开评估。研究团队针对48种本土物种获取了详细的原位（in-situ）调查记录，根据其生境与地质基质偏好进行分组，通过网格单元绘制分布范围，并结合物种分组对分布格局开展分析。希俄斯岛与切什梅-卡拉布伦半岛的物种均呈现五种分布格局：广布、局地广布、局地受限、零星分布与稀有分布。希俄斯岛与切什梅-卡拉布伦半岛有50%至62%的物种呈现相似的分布格局以及生境、地质基质偏好趋势，该结果契合此前关于东爱琴海群岛与邻近安纳托利亚地区存在紧密生物地理亲缘关系的研究证据。两个区域间观测到的差异可归因于岛屿效应、人类活动影响，以及混杂岩（melange）——一种以阐明区域地球动力学演化关键作用而闻名的古老岩石基质。希俄斯岛广布物种与局地广布物种的分布格局为密度补偿与生态位偏移响应提供了佐证，但这类现象在岛屿植物种群中的实际发生情况仍有待阐明。总体而言，物种分布格局——尤其是稀有物种的分布格局——反映了爱琴海区域复杂的地质历史、古地理学（palaeogeography）与人类活动影响。