Ecology and Evolution of Plant-Enemy Interactions during Early Colonization: Messages from a Land-Rising Archipelago

Plant-enemy interactions on islands are shaped by ecological and evolutionary processes during the history of the islands. It is, however, rare to be able to observe the foundational phases on islands, but opportunities exist in areas with land-rising coastlines, such as in parts of the Baltic Sea. Using several plant-enemy systems, a pattern appears where low-defended plants are typically dominating on young islands and on shores of older islands. One reason for this pattern is that the main seed sources are plants from sites with low enemy attack rates and with high reproductive output. Later on in succession, once herbivore populations become established and attack rates increase, selection acts to increase plant resistance traits. Even though the number of studied plant species is still low, it is apparent that processes during foundational phases may be complex and simplified explanations for current patterns may be hard to find.