Vegetation dynamics

We record vegetation dynamics both by manual and digital photography surveys of 1 m2 quadrats. We also measure growth increments of ling heather (Calluna vulgaris). The major vegetation types observed at the sites are: heather (Calluna) dominated shrub vegetation, sedge (Eriophorum spp.), some rush near stream areas, Sphagnum and other moss cover, the latter with a large component of Hypnum jutlandicum and Campylopus spp. In 2012, before mowing or burning, sites were characterised by similarly tall heather stands (~35 cm) with notably low plant diversity (ca. 8 or 14 species per 1 x 1 m plot areas and across the entire 5 x 5 m monitoring plots, respectively). The dense Calluna cover (~60%) further contained mostly about 10% fractions of sedges (Eriophorum sp.), Sphagnum moss and other moss. All very typical for heather-dominated grouse moor. All sites are classed as NVC M19a (based on the % plant species cover per uncut plots).

Calluna patch

Sedge patch

Sphagnum patch

Nidderdale vegetation survey at treatment sub-catchment:

shown are the 1 x 1 m survey plots and 5 x 5 m plots.

Mossdale vegetation survey at treatment sub-catchment:

shown are the 1 x 1 m survey plots and 5 x 5 m plots.

Whitendale vegetation survey at treatment sub-catchment:

shown are the 1 x 1 m survey plots and 5 x 5 m plots.

We did the first vegetation survey in 2012 with the help of Clare Rickerby (Edinburgh, now St Andrews: Clare the Botanist) and together with our PhD student, Phoebe Morton (York). In the latter years we also had help from Julie Smith (Caledonian Conservation). All sites showed on average >50% heather (Calluna) coverage with an average maximum height of around 35 cm. However, plant diversity is generally low and decreases in the order of: Mossdale > Whitendale > Nidderdale. Furthermore, at Whitendale there seems to have been some frost damage during the winters of 2011, 2012, particularly at the treatment site (see picture above; the larger fence posts indicate the 5 x 5 m grazing exclusion plots). Treatments (mowing etc.) started early in 2013 and we have since remeasured annually.

We repeated the vegetation surveys annual (2013-2019), again with the help of either Clare or Julie (A Heinemeyer was always present), after the plots had either been mown, burnt or left uncut as a no-treatment "do nothing" control. We took 1 x 1 m pictures as previously and also 5 x 5 m plot pictures using a wide angle GoPro camera on a telescope pole.

5 x 5 m pictures with a GoPro Field of view of a 5 x 5 m plot (uncut) 1 x 1 m detailed quadrat work Longest selfie picture (3.5 m!)

Mown plot with brash removed Mown plot with brash left in place Burnt plot with visible moss damage Uncut plot with intact vegetation

We used the MAVIS software (CEH: Modular Analysis of Vegetation Information System (Malvis)) to derive NVC categories in order to relate our study sites and any vegetation composition change over time to other studies. We also specifically assessed heather height and regrowth over time in relation to total vegetation cover. A notable difference was the slow heather regrowth after burning (germination) compared to that on mown plots (re-sprouting from stems). However, heather beetle damage caused reduced heather heights and cover, particularly in 2014/15 and 2017/18, at the two wetter sites (Mossdale and Whitendale, respectively):

Heather height over time
Main vegetation cover 2019

Total vegetation cover was assessed either as exposed (i.e. top layer view; 100%) or as total (all layers; >=100%) cover. There were clear differences in the exposed and total cover, relating to management exposing surface moss cover and regrowing taller vegetation covering those layers over subsequent years:

Exposed vegetation cover
Total cover