The ghost fruits of Madagascar

Study analyses seed dispersal in Madagascar's endemic flora to identify plants whose dispersal partners may be extinct

GBIF-mediated data resources used : 487,759 species occurrences
Propithecus verreauxi
Propithecus verreauxi observed in southern Madagascar by figschool (CC BY 4.0)

With extreme levels of endemism, Madagascar is home to plants and vertebrates, of which more than 80 per cent exist nowhere else on the planet. Some plants have evolved in mutualistic relationships with
frugivore lemurs as seed dispersers, almost all of which are severely threatened.

In this study, authors explore seed dispersal on the island, analysing more than 3,000 flowering plants, identifying disperser animal groups, animal co-occurrences based on GBIF-mediated data, and comparing seed and gape (mouth) size to predict anachronistic species where no apparent extant disperser is available.

Their results find only 179 plant species with direct evidence of dispersal by extant frugivores in Madagascar. Based on seed size and disperser groups, two species, Erythrina hazomboay and Borassus madagascariensis appear to have completely lost their main dispersers to extinction.

With more than 100 species, lemurs are the main mammal disperser in Madagascar. Sixteen per cent of the analysed plant species, however, lacked co-occurring lemur species with an appropriate gape size, suggesting that local extinctions are leading to dysfunctional dispersal.

Albert-Daviaud A, Buerki S, Onjalalaina GE, Perillo S, Rabarijaona R, Razafindratsima OH, Sato H, Valenta K, Wright PC and Stuppy W (2020) The ghost fruits of Madagascar: Identifying dysfunctional seed dispersal in Madagascar’s endemic flora. Biological Conservation. Elsevier BV 242: 108438. Available at: https://doi.org/10.1016/j.biocon.2020.108438