Island biogeography: an avenue for research in bryology

In the present review, we provide an updated account on the level of knowledge in island bryophyte biogeography. In the framework of the 50 most fundamental questions for present and future island biology research highlighted by Patiño et al. (2017), we summarize current knowledge in bryophyte island biogeography and outline main research avenues for the future in the field. We found that only about 50% of the key current questions in island biogeography have been addressed to some extent, at least once, in bryophytes. Even fundamental questions that have caught the attention of ecologists since more than one century, such as the species-area relationship, have only rarely been dealt with in bryophytes. The application of the Island Biogeography Theory therefore opens an avenue for research in bryology, and we discuss the most salient features, including species and community phylogenetics, biotic interactions, and invasion biology.

Islands as Evolutionary Laboratories

Islands have inspired biologists for hundreds of years as locations that foster unique biotic assemblages and provide insights into ecological and evolutionary processes dictating life globally. Although by classic definition islands are subcontinental land masses surrounded by water, from a biological perspective, islands can be defined broadly as any isolated piece of habitat that is surrounded by distinct environmental conditions. Therefore the study of island biology applies to any area that is habitable for a given set of organisms and is separated from a source by an inhospitable matrix. Biological islands can include lakes surrounded by land and mountaintops, caves, and land fragments surrounded by habitat in which an organism of interest cannot survive or reproduce. Given sufficient isolation, these attributes can result in a distinctive biota.

Island biology: looking towards the future

Oceanic islands are renowned for the profound scientific insights that their fascinating biotas have provided to biologists during the past two centuries. Research presented at Island Biology 2014—an international conference, held in Honolulu, Hawaii (7–11 July 2014), which attracted 253 presenters and 430 participants from at least 35 countries 1 —demonstrated that islands are reclaiming a leading role in ecology and evolution, especially for synthetic studies at the intersections of macroecology, evolution, community ecology and applied ecology. New dynamics in island biology are stimulated by four major developments. We are experiencing the emergence of a truly global and comprehensive island research community incorporating previously neglected islands and taxa. Macroecology and big-data analyses yield a wealth of global-scale synthetic studies and detailed multi-island comparisons, while other modern research approaches such as genomics, phylogenetic and functional ecology, and palaeoecology, are also dispersing to islands. And, increasingly tight collaborations between basic research and conservation management make islands places where new conservation solutions for the twenty-first century are being tested. Islands are home to a disproportionate share of the world's rare (and extinct) species, and there is an urgent need to develop increasingly collaborative and innovative research to address their conservation requirements.