Assessing Hotspots of Evolutionary History with Data from Multiple Phylogenies: An Analysis of Endemic Clades from New Caledonia

Abstract

The great bulk of the present knowledge of the Tree of Life comes from many phylogenies, each with relatively few tips, but with lots of diversity concerning taxa and characters sampled and methods of analysis used. For several biodiversity hotspots this is the kind of data available and ready to be used to have a better understanding on the evolutionary patterns and to identify areas with remarkable evolutionary history. But relying on data coming from independent studies raises some methodological challenges of standardization, comparability and assessments of bias to make the best use of the currently available information. To bring light to this subject here we analyzed the distribution of phylogenetic diversity in New Caledonia, a biodiversity hotspot characterized by strong rates of regional and internal endemicity. We used a dataset with 18 phylogenies distributed in 16 study sites, and based our analysis on the measure Ws sum. Our study comprises the analysis of (1) the role of the number of phylogenies on site' scores and a strategy of standardization of the dataset by the number of phylogenies; (2) the infl uence of species richness on site scores and the design of the measure Ws ranks to focus on the most divergent species of each phylogeny; (3) an assessment of the infl uence of individual phylogenies; (4) a resampling strategy using multiple phylogenies to verify the results' stability.

Outstanding micro-endemism in New Caledonia: More than one out of ten animal species have a very restricted distribution range

“…Although micro-endemicity has frequently been reported in researches for different groups of the New Caledonian fauna [ 10 , 14 , 16 , 23 , 26 – 27 , 31 ], the present study is the first to be specifically designed to quantify its distribution range, estimate its frequency, and determine the extent to which these findings are common to several taxonomic groups. It is also the first time that the distribution range of this fauna is analyzed taking sampling effort into account.…”

“…Our results provide estimates of the distribution range in a wide range of species, which will facilitate the re-assessment of the status of species from at least 12 different orders ( S1 Table and S2 Table ). Considering the ongoing environmental pressure and destruction of several habitats in New Caledonia [ 10 , 19 – 23 ], the fact that all species with a distribution range <10 km 2 occur in a single locality, and that population sizes are frequently very small, and that very few of these species occur in areas legally protected, a great number of these micro-endemic species are very likely to be Critically Endangered.…”

“…New Caledonia is the oldest oceanic island [ 17 , 18 ]. It is considered a biodiversity hotspot due to its magnificent flora and fauna, which is characterized by a high number of locally endemic species that are under threat due to nickel mining, repeated fires, and invasive species [ 10 , 19 – 23 ]. Mentions of micro-endemicity permeate the literature on the New Caledonian fauna and flora.…”

Ten false ideas about New Caledonia biogeography

“…() showed that the distribution area of microendemic species increased considerably with time, placing the oldest endemics in secondary sympatry. In this context, some Quaternary forest climatic refuges could be centres of endemism for some groups at the least, but they do not necessarily equate to centres of diversity or even centres of origin where a significant amount of deep time evolution is conserved (Pellens et al., ). As an example, the most emblematical relict in New Caledonia, Amborella trichopoda , considered by many as the sister‐group of flowering plants, has a quite wide distribution on the island and is not restricted to particular areas of long‐term stability (Poncet et al., ; Pouteau et al., ).…”

The informative value of museum collections for ecology and conservation: A comparison with target sampling in the Brazilian Atlantic forest

“…They are collected by direct search on their specific habitats, or, indirectly, by collectors searching for xylophagous insects. Adult males can be captured with light traps, although it rarely occurs [ 31 , 32 , 39 ].…”