The relationship of bryophyte regeneration to heather canopy height following moorland burning on the North York Moors

Abstract

When managing heather (Calluna vulgaris) moorland by burning, the interval between burning must be long enough for successful bryophyte development, but not so long that excessive dry plant matter accumulates, as this can result in hot burns that damage the peat surface and cause peat erosion. Age and stage of heather development may not be the most informative and consistent indicators of recovery, as they vary considerably with different environmental conditions. A simple and reliable indicator as to when burning should occur was sought by measuring the abundance of bryophyte species on moorland plots with different phases of heather redevelopment after burning. Four dry heath (NVC community H12a) and three wet heath (NVC community M16d) sites with varying ages of heather between 1 and >25 years were selected on Spaunton Moor, North Yorkshire, UK. Overall vegetation height and the number of bryophyte growing tips were recorded. Thirty-nine bryophyte species were recorded; 23 in dry heath and 30 in wet heath. Vascular plant canopy height was negatively correlated with the number of stems of Campylopus introflexus and Sphagnum species, and positively correlated with Hypnum jutlandicum. On dry heath, the abundance of Campylopus introflexus was greatest at a canopy height under 30 cm; Hypnum jutlandicum increased in abundance at this canopy height, and declined when the canopy reached approximately 55 cm. On wet heath, the abundance of Sphagnum species and Campylopus introflexus was greatest at a canopy height under 30 cm; Hypnum jutlandicum increased in abundance at a canopy height of 20 cm, with maximum abundance at a canopy height of 50 cm. Based on the recovery of the bryophyte species, burning is indicated when the canopy height reaches approximately 41 to 54 cm on dry heath, and 25 to 30 cm on wet heath. These canopy heights span a range of ages and stages of heather development making it difficult to translate these into a burning rotation based on these variables. As a result, canopy height was a more reliable indicator of bryophyte recovery than the age or stage of development of heather on Spaunton Moor. Further research is required to investigate the consistency of height as an indicator for burning on moorlands with different environmental conditions.

Keywords:

• BRYOPHYTE RECOVERY
• BURNING CYCLES
• CALLUNA VULGARIS
• HEATHLAND
• MOORLAND MANAGEMENT
• NORTH YORK MOORS