TY - JOUR

T1 - Changes in tree growth resulting from simulated browsing have limited effects on soil biological properties.

AU - Carline, Kathryn A.

AU - Bardgett, Richard D.

PY - 2005/12

Y1 - 2005/12

N2 - Herbivores can indirectly affect ecosystem productivity by modifying feedbacks that occur between dominant plants and below-ground properties, especially through altering nutrient availability in soil. The aim of this study was to examine, under controlled conditions, the effect of simulated browsing by large herbivores on the growth characteristics of downy birch (Betula pubescens), a dominant tree species of native regenerating forests in northern Britain, and to determine how effects of browsing on tree growth cascaded through to soil microbial communities, thereby affecting nutrient availability in soil. Downy birch seedlings were grown in mesocosms for 2 years and subjected to simulated browsing in the form of defoliation and clipping treatments. Upon destructive harvest, a number of measures of both tree growth characteristics and soil biological and nutrient properties were made. Clipping of birch trees significantly reduced total root biomass (27%), fine root biomass (29%), coarse root biomass (27%) and above-ground biomass (18%), whereas defoliated trees were significantly shorter than non-defoliated trees. Despite these significant and negative effects of browsing on tree growth, soil biological properties remained largely unaffected, other than rates of N mineralisation, which were greater under defoliated trees. We conclude that other factors, such as herbivore effects on litter quantity and quality which feedback to soil biological properties in the longer-term are more important in determining ecosystem responses to browsing.

AB - Herbivores can indirectly affect ecosystem productivity by modifying feedbacks that occur between dominant plants and below-ground properties, especially through altering nutrient availability in soil. The aim of this study was to examine, under controlled conditions, the effect of simulated browsing by large herbivores on the growth characteristics of downy birch (Betula pubescens), a dominant tree species of native regenerating forests in northern Britain, and to determine how effects of browsing on tree growth cascaded through to soil microbial communities, thereby affecting nutrient availability in soil. Downy birch seedlings were grown in mesocosms for 2 years and subjected to simulated browsing in the form of defoliation and clipping treatments. Upon destructive harvest, a number of measures of both tree growth characteristics and soil biological and nutrient properties were made. Clipping of birch trees significantly reduced total root biomass (27%), fine root biomass (29%), coarse root biomass (27%) and above-ground biomass (18%), whereas defoliated trees were significantly shorter than non-defoliated trees. Despite these significant and negative effects of browsing on tree growth, soil biological properties remained largely unaffected, other than rates of N mineralisation, which were greater under defoliated trees. We conclude that other factors, such as herbivore effects on litter quantity and quality which feedback to soil biological properties in the longer-term are more important in determining ecosystem responses to browsing.

KW - Browsing

KW - Birch

KW - Nutrient cycling

KW - Root biomass

KW - Herbivory

U2 - 10.1016/j.soilbio.2005.04.008

DO - 10.1016/j.soilbio.2005.04.008

M3 - Journal article

VL - 37

SP - 2306

EP - 2314

JO - Soil Biology and Biochemistry

JF - Soil Biology and Biochemistry

SN - 0038-0717

IS - 12

ER -