Historical legacies in the geographical diversity patterns of New World palm (Arecaceae) subfamilies

The extent to which species richness patterns of the major palm subfamilies in the Americas are controlled by lineage history was studied. Based on the fossil record, we suggest that the subfamily Coryphoideae has followed a boreotropical dispersal route into Central and South America, whereas Calamoideae (tribe Lepidocaryeae), Ceroxyloideae and Arecoideae have Gondwana/South America-biased histories. However, Arecoideae has been present and diverse in both South and Central America at least since the early Tertiary. We used regression analyses to evaluate the relative importance of environmental factors and spatial variables (as substitutes for historical or other non-environmental factors) as determinants of geographical variation in species richness for each subfamily. Given the different lineage histories, we hypothesized that: (1) coryphoid richness should be least strongly controlled by the modern environment and exhibit a strong non-environmental bias towards Central and North America, reflecting its boreotropical invasion route, (2) calamoid species richness should exhibit a non-environmental bias towards South America, reflecting its long African–South American history, and (3) arecoid species richness should be most strongly environmentally determined, reflecting the long arecoid residency in both Central and South America. The regression analyses confirmed the hypothesized effects of lineage history on the geographical patterns in species richness. Hence, modern species richness patterns in the New World palm subfamilies strongly reflect their divergent biogeographical histories.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 113–125.     

A trait-based approach to assess climate change sensitivity of freshwater invertebrates across Swedish ecoregions

Freshwater habitats and organisms are among the most threatened on Earth, and freshwater ecosystems have been subject to large biodiversity losses. We developed a Climate Change Sensitivity （CCS） indicator based on trait information for a selection of stream- and lake-dwelling Ephemeroptera, Plecoptera and Trichoptera taxa. We calculated the CCS scores based on ten species traits identified as sensitive to global climate change. We then assessed climate change sensitivity between the six main ecoregions of Sweden as well as the three Swedish regions based on lilies. This was done using biological data from 1,382 stream and lake sites where we compared large-scale （ecoregional） patterns in climate change sensitivity with potential future exposure of these ecosystems to increased temperatures using ensemble-modelled future changes in air temperature. Current （1961-1990） measured temperature and ensemble-modelled future （2100） temperature showed an increase from the northernmost towards the southern ecoregions, whereas the predicted temperature change increased from south to north. The CCS indicator scores were highest in the two northernmost boreal ecoregions where we also can expect the largest global climate change-induced increase in temperature, indicating an unfortunate congruence of exposure and sensitivity to climate change. These results are of vital importance when planning and implementing management and conservation strategies in freshwater ecosystems, e.g., to mitigate increased temperatures using riparian buffer strips. We conclude that traits information on taxa specialization, e.g., in terms of feeding specialism or taxa having a preference for high altitudes as well as sensitivity to changes in temperature are important when assessing the risk from future global climate change to freshwater ecosystems [Current Zoology 60 （2）： 221-232, 2014].