Niche dynamics of Memecylon in Sri Lanka: distribution patterns, climate change effects, and conservation priorities

Aim: Recent climate projections have shown that the distribution of
organisms in island biotas is highly affected by climate change. Here, we
present the results of the analysis of niche dynamics of a plant group,
Memecylon on Sri Lanka, an island, using species occurrences and climate
data. We aim to determine which climate variables explain current
distribution, model how climate change impacts the availability of
suitable habitat for Memecylon, and determine conservation priority areas
for Sri Lankan Memecylon. Location: Sri Lanka Methods: We used
georeferenced occurrence data of Sri Lankan Memecylon to develop
ecological niche models and assess both current and future potential
distributions under six climate change scenarios in 2041-2060 and
2061-2080. We also overlaid land-cover, and protected area maps and
performed a gap analysis to understand the impacts of land-cover changes
on Memecylon distributions and propose new areas for conservation.
Results: Differences among suitable habitats of Memecylon were found to be
related to patterns of endemism. Under varying future climate scenarios,
endemic groups were predicted to experience habitat shifts, gains, or
losses. The narrow endemic Memecylon restricted to the montane zone were
predicted to be the most impacted by climate change. Projections also
indicated that changes in species’ habitats can be expected as early as
2041-2060. Gap analysis showed that while narrow endemic categories are
considerably protected as demonstrated by their overlap with protected
areas, more conservation efforts in Sri Lankan forests containing wide
endemic and non-endemic Memecylon are needed. Main conclusions: This
research helped clarify general patterns of responses of Sri Lankan
Memecylon to global climate change. Data from this study are useful for
designing measures aimed at filling the gaps in forest conservation on
this island.