On islands, evolutionary but not functional originality is rare

Abstract

Functionally and evolutionary original species are those whose traits or evolutionary history are shared by few others in a given set. These original species promote ecosystem multifunctionality, the ability to cope with an uncertain future, future benefits to society and therefore have a high conservation value. A potential signal of their extinction risks is their rarity (stating for geographic range-restriction in this study). On islands, life in isolation conducted to the rise of a multitude of original forms and functions as well as to high rates of endemism. Not only patterns and processes of insular originality are unexplained but the relationship between originality and rarity is still unknown. The aim of this study is to assess how original insular species are, to explore whether original species are rare or not and to investigate the factors that may explain the rarity of original species. We first compared the functional and evolutionary originality of monocotyledon species and whether continental or insular species were more original. We found that species restricted to islands were more original than continental species and, although functionally and evolutionary original species were dissimilar, many occurred on similar territories so that regional conservation strategies may allow to conserve these distinct forms. Yet, evolutionary original species were significantly more range-restricted than those which were distinct in their traits. Reflecting their rarity, evolutionary original species had low dispersal abilities and were found on islands where settlement may have been facilitated. On the opposite, functionally original species could reach a wider set of islands by being transported on long-distances. While some mechanisms may both explain rarity and originality such as extinctions, others may be specific to each of these biodiversity facets, in particular diversification, niche shift and expansion, and dispersal power. Implications for conservation are huge: original species are range-restricted and mostly found in the most threatened systems of the world, i.e. islands, endangering the reservoir of features against an uncertain future.

Online photovoice to engage indigenous Cook Islands youth in the exploration of social and ecological wellbeing amidst a global disruption

“…Environmentalists and conservationists appropriated the island imagery of primitive societies in need of modernization and economic development by adding a new layer of perceived environmental vulnerabilities to meet their sustainable development agenda (Scheyvens and Momsen, 2008). Indeed, there is a great wealth of research that recognizes the role of physical characteristics and climatic processes in determining the vulnerability of Pacific Islands societies to exogenous disruptions (Veron et al, 2019;Filho, 2020;De Scally and Doberstein, 2022). In the Pacific region, some of the large-scale impacts of climate change include increased variability in rainfall events (McGree et al, 2014), stronger and more frequent tropical cyclones (McMichael et al, 2019), rising sea-level (Kulp and Strauss, 2019), increase in air and sea surface temperatures (De Scally and Doberstein, 2022), and changes in regional climatic systems, particularly the South Pacific Convergence Zone (SPCZ) and El Nino Southern Oscillation (ENSO) (Cai and Marks, 2021).…”

The effectiveness of a large protected area to conserve a global endemism hotspot may vanish in the face of climate and land-use changes

“…Unfortunately, the biophysical features of islands and mountains also make these endemic hotspots highly vulnerable to climate change. Because of spatial isolation and limited surface area of islands and mountain tops, species specialized on these habitat types are constrained in their migration to track their climate envelope, and are confined to smaller and often higher elevation (Dirnböck et al, 2011;Kidane et al, 2019;Veron et al, 2019;. These endemic species therefore face high extinction risks in the face of climate change (Malcolm et al, 2006;Manes et al, 2021).…”