Differences between the floras of the North and South Moluccas (Indonesia)

Abstract

The north and south Moluccas (Indonesia) have very different geotectonic origins and, due to that, a difference in flora is to be expected. The north Moluccas moved westwards along the north coast of New Guinea to their present position, the south Moluccas moved north from Australia. On the other hand, a comparable climate in both areas and (partial) submergence during tectonic movement may have equalized both floras. Collection data from Naturalis Biodiversity Center on 1559 species in 121 families treated in Flora Malesiana were collected for the Moluccas, Sulawesi, and Western New Guinea (latitudes 9.2°S and 5.6°N and longitudes 118.8°E and 141°E) and georeferenced. Species Distribution Models (SDMs) were made, based on least correlated climate and edaphic variables, using only those species that were present in 5 or more grid cells of 5‐arc minutes and models were tested for deviation from random. Both areas differ significantly and share only 50%–65% of their species. The 348 significant SDMs differ much less, though still significantly, sharing 91% of the species. Despite strong climatic and edaphic similarities between the North and South Moluccas, they differ greatly in species composition, which is in support of geotectonic reconstructions. The differences between the North and South Moluccas suggest that the continuous dispersal barriers and tectonic backgrounds have influenced their current flora.

Biogeographic Patterns in the Pacific and Australasian Regions

“…Zhao et al () and Rutgrink et al () focus on taxa in Malesia. In their biogeographic analysis of Prunus subgenus Laurocerasus section Mesopygeum , Zhao et al () found that the Wallace Line is an important line of demarcation for the two major clades within the section.…”

“…This special issue includes works presented at this symposium, but also contains studies from the Australasian region, which neighbors the Pacific region and in many cases serves as the source area for Pacific oceanic island colonization. This issue comprises works that aim to reconstruct patterns throughout the entire Pacific (Appelhans et al, ) or that focus on islands groups in the Pacific (Paetzold et al, ; Price & Wagner, ) or parts of Australasia (Miller et al, ; Rutgrink et al, ; Zhao et al, ).…”

“…Rutgrink et al () look beyond the broad subdivision of Malesia into two (West and East of Wallace's Line) and three regions (Sunda shelf, Wallacea, Sahul shelf) respectively. They examined the composition of the floras of the north and south Moluccas, which are part of the Sahul shelf.…”

A Latest Discovery of Austronesian Rock Art in the North Peninsula of Buano Island, Maluku

“…General evidence of archaeological findings in North Maluku are older than the archaeological findings in the Southern Maluku Islands. Based on estimates of the oldest archaeological remains, geographically, the cultural time character of the Southern Maluku Islands were also generally separated from the Aru Islands area (Rutgrink, Visser, & van Welzen, 2018). Aru Islands is integrated into the Sahul Shelf, especially during the Last Glacial Maximum and also separated from the Southwest Maluku Region, which includes Wetar Island, Timor Island, Kisar Island, Leti Islands, to Babar Islands (O'Connell & Allen, 2007;Ray & Adams, 2001;Roberts et al, 2020;Sathiamurthy & Voris, 2006).…”

Weda, a new genus with two new species of Euphorbiaceae‐Crotonoideae from Halmahera (North Maluku, Indonesia) and phylogenetic relationships of the Australasian tribe Ricinocarpeae

“…A review of the checklists of the Malesian Euphorbiaceae (Airy Shaw, 1982; van Welzen, 2017) shows that 8 of the 81 recorded Moluccan species (in 26 genera) are endemic. The Moluccas are often treated as a monolithic biogeographic unit (i.e., same climate), but recently it was shown that the very different tectonic origins of North and South Moluccas warrant the recognition of two biogeographic provinces (Rutgrink et al, 2018).…”