TY - JOUR

T1 - Molinia caerulea responses to N and P fertilisation in a dry heathland ecosystem (NW-Germany)

AU - Falk, Kerstin

AU - Friedrich, Uta

AU - Oheimb, Goddert

AU - Mischke, Kerstin

AU - Merkle, Konrad

AU - Meyer, Hartmut

AU - Härdtle, Werner

PY - 2010/7

Y1 - 2010/7

N2 - In the present study we analysed whether airborne N pollution may constitute one important driver for the encroachment of Molinia caerulea in dry heathland ecosystems. Based on full-factorial field experiments (in 2006 and 2008) and complementary greenhouse experiments (in 2008), we quantified growth responses of Molinia caerulea to N and P fertilisation (50 kg N ha(-1) year(-1), 20 kg P ha(-1) year(-1)). Aboveground biomass production of Molinia caerulea was limited by P in 2006, but by N in both experiments in 2008. In the greenhouse experiment, N addition caused a sixfold increase of the biomass of vegetative tillers, and in all experiments the biomass and numbers of flowering tillers showed a significant increase due to fertilisation. Our experiments indicated that growth of Molinia caerulea was primarily limited by N, but in dry heaths the kind of nutrient limitation may be mediated by other factors such as water availability during the vegetative period. Shifts in biomass allocation patterns resulting from N fertilisation showed that Molinia caerulea encroachment in dry heaths is not only attributable to increased leaf biomass, but also due to higher investments in reproductive tissue that allow for increased seed production and thus accelerated encroachment of seedlings in places where the dwarf shrub canopy has been opened after disturbance.

AB - In the present study we analysed whether airborne N pollution may constitute one important driver for the encroachment of Molinia caerulea in dry heathland ecosystems. Based on full-factorial field experiments (in 2006 and 2008) and complementary greenhouse experiments (in 2008), we quantified growth responses of Molinia caerulea to N and P fertilisation (50 kg N ha(-1) year(-1), 20 kg P ha(-1) year(-1)). Aboveground biomass production of Molinia caerulea was limited by P in 2006, but by N in both experiments in 2008. In the greenhouse experiment, N addition caused a sixfold increase of the biomass of vegetative tillers, and in all experiments the biomass and numbers of flowering tillers showed a significant increase due to fertilisation. Our experiments indicated that growth of Molinia caerulea was primarily limited by N, but in dry heaths the kind of nutrient limitation may be mediated by other factors such as water availability during the vegetative period. Shifts in biomass allocation patterns resulting from N fertilisation showed that Molinia caerulea encroachment in dry heaths is not only attributable to increased leaf biomass, but also due to higher investments in reproductive tissue that allow for increased seed production and thus accelerated encroachment of seedlings in places where the dwarf shrub canopy has been opened after disturbance.

KW - Ecosystems Research

KW - Biology

KW - Biomass allocation

KW - N:P ratio

KW - Nutrient limitation

KW - Phosphorous supply

KW - Productivity

U2 - 10.1007/s11258-010-9720-2

DO - 10.1007/s11258-010-9720-2

M3 - Journal articles

VL - 209

SP - 47

EP - 56

JO - Plant Ecology

JF - Plant Ecology

SN - 1385-0237

IS - 1

ER -