Soil phosphorus dynamics along a short-term ecological restoration trajectory of a coastal sandplain forest in New Zealand

Abstract

We aim to understand the impact of ecological restoration on soil biogeochemistry, and the interrelationship between vegetation and soil phosphorus. In a study of two different-aged soils in coastal New Zealand, soils are described along a transition from abandoned agricultural pasture, through 6-year old restoration plots, towards forest fragments that have been largely undisturbed for 75 and 166 years. Soil biogeochemistry varied spatially along this restoration trajectory; there were profound changes in surface soil, but little impact on deeper soil horizons. In the early stages, soil organic matter accumulation and decomposition, and increasing demand of N from fast-growing plants corresponded with rapid nutrient mineralization. Loss of soil total P, an increase of occluded P, and the increasing importance of soil organic P as soils weathered and aged, supported conceptual models of longer-term soil pedogenesis. There was no evidence that the success of the establishment of plants varied across the site, but this is a first report of vegetation establishment during ecological restoration markedly impacting soil P dynamics and biogeochemistry.