Parallel ecological filtering of ultramafic soils in three distant island floras

Abstract

Aim Alexander von Humboldt observed that plant communities on different continents but under similar climatic conditions shared few common species but often contained representatives of the same genera or higher taxonomic groups. To test if this observation can be extended to substrate type, we explored whether a phylogenetic signature could be seen among floras growing on ultramafic substrates that present challenging edaphic conditions for plant growth and are well‐known for their distinctive vegetation. Location Cuba, Madagascar, New Caledonia. Taxon Angiosperms. Methods We compared the floras of Cuba, Madagascar and New Caledonia to test whether the same plant families were under‐ or over‐represented on the ultramafic substrates of the three islands. Results Pairwise comparisons showed that plant orders and families tended to have the same behaviour on the three islands, i.e. ultramafic substrates filtered (in favour of or against) the same plant groups in the three biogeographical distinct areas. The COM clade (comprising Celastrales, Oxalidales and Malpighiales) appears to be over‐represented on ultramafic substrates in all three islands and contains over half of the world's known nickel hyperaccumulators. Main conclusions Our analyses provide support for Humboldt's observation by showing that ecological sorting can favour the same plant lineages in similar environments in different biogeographical regions.

Hierarchical phylogenetic community assembly of soil protists in a temperate agricultural field

“…We observed a turnover of relatively closely related taxa (from sequence variants to genus-level clades) across soil depths but a turnover of relatively distantly related taxa (above the genus level up to order level) across soil habitats. This presents similarity with Humboldt's observations on worldwide floras (Humboldt and Bonpland 1814) as recently confirmed for ultramafic island's flora (Pillon et al, 2019) but also for AM fungi in agricultural fields (Roy et al, 2019;Roy et al, 2021), mammal gut bacteria (Groussin et al, 2017;Martiny et al, 2015) and birds and mammals at global scales (Mazel et al, 2017). This suggests that soil Cercozoa community assembly at the field scale is driven by niche-based processes shaped by evolutionary legacy of adaptation to conditions primarily related to soil compartment, followed by soil layer.…”

“…Community structure (occurrence and abundance of taxa within a community) and its change across time or space (e.g., betadiversity) are traditionally studied at species level. However, the relative importance of the processes shaping these patterns depends on the phylogenetic scale of taxon delimitation (Cavender‐Bares et al, 2006; Chalmandrier et al, 2019; Groussin et al, 2017; Martiny et al, 2015; Mazel et al, 2017; Pillon et al, 2019; Roy et al, 2019). For example, if dispersal limitation has been important at different periods in the past, it would today manifest in extent taxa geographic distribution at different phylogenetic levels (e.g., disjunct distribution of higher clades if dispersal limitation was important in the deep past).…”

The X-ray fluorescence screening of multiple elements in herbarium specimens from the Neotropical region reveals new records of metal accumulation in plants

“…The Cuban and New Caledonian metallophyte flora have interesting similarities, but also differences associated with their distinct biogeographical situation. 69 On both islands, Ni hyperaccumulation is observed in species of the Celastraceae and Euphorbiaceae families, and Mn hyperaccumulation in Myrtaceae. In addition, Ni hyperaccumulation has been reported in endemic species of the genera Casearia (Salicaceae), Phyllanthus (Phyllanthaceae), and Psychotria (Rubiaceae), that is likely the outcome of convergence.…”

Floristics of forests across low nutrient soils in Sulawesi, Indonesia

“…Park. An initial comparison suggests that the Celestrales, Oxalidales, Malphigiales (COM) clade that often dominate ultramafic floras (Pillon et al, 2019) account for 17% of stems at our sites, whereas, in Lore Lindu (albeit at higher elevations than our sites), COM species account for < 10% of stems (Brambach et al, 2017). Unpacking how the stressful soils of Sulawesi differentially affect clades should be possible with a larger dataset (Fernandez-Going et al, 2013).…”

“…One of the only places where the flora has been examined thoroughly is the Lore Lindu National Park (Brambach, Leuschner, Tjoa, & Culmsee, 2017, 2020; Culmsee & Leuschner, 2013; Culmsee, Leuschner, Moser, & Pitopang, 2010; Culmsee, Pitopang, Mangopo, & Sabir, 2011), a site that covers only a few of the soil types found in Sulawesi (Cannon, Summers, Harting, & Kessler, 2007). The island has many soil types including limestone and ultramafic soils that possess a chemistry that many plants are ill‐equipped to tolerate (Galey, van der Ent, Iqbal, & Rajakaruna, 2017; Kong et al, 2017; Nie et al, 2011; Pillon et al, 2019). Limestone soils have high pH and high magnesium and calcium concentrations (Nie et al, 2011), whilst ultramafic soils are rich in many often toxic metals and low in phosphorus (Proctor, 2003).…”