Is hyperaccumulation of nickel worthwhile in non-serpentine soils?

Ni-hyperaccumulating species produce high-Ni litters and potentially influence important ecosystem processes such as decomposition. According to the elemental allelopathy hypothesis of hyperaccumulation, the restriction of the majority of metal hyperaccumulators in metaliferous soils may be dependent on litter decomposition.

Litter mass remaining (LMR) in the mixed-species litterbags relative to the expected values calculated from the corresponding single-species litterbags. Values are plotted against the days of field exposure. Points for which the 95 % CIs cross y = 0 represent significant additive interactions; points with positive values for which the 95 % CIs do not cross y = 0 represent significant non-additive antagonistic interactions; and points with negative values for which the 95 % CIs do not cross y = 0 represent significant non-additive synergistic interactions. Full details in Adamidis *et al.* (2016).

Adamidis et al. using for the first time mixed-species litters containing hyperaccumulated Ni:

indicate the presence of Ni-resistant decomposers on serpentine soil,
demonstrate the selective decomposition of low-Ni parts of litters on non-serpentine soils and
give support to the elemental allelopathy hypothesis, presenting the potential selective advantages acquired by metal
hyperaccumulators through litter decomposition on serpentine soils.