Regeneration patterns in a Calluna vulgaris heathland in the Cantabrian mountains (NW Spain): effects of burning, cutting and ploughing

Abstract

Regeneration after experimental disturbances (burning, cutting and ploughing) was studied in a heathland dominated by Calluna vulgaris (L.) Hull located in NW Spain. Regeneration of C. vulgaris was better after burning and ploughing than after cutting. When cut, this species was replaced by another resprouting ericaceous species, Erica tetralix L. Calluna seedlings suffered high mortality in the third and fourth years after all treatments. Herbaceous species, which dominated during the first year of the secondary succession, were gradually replaced by woody species characteristic of that area from the sixth and seventh years after cutting and burning, and during the tenth year after ploughing. Multivariate analysis showed a clear separation between the different treatments, reflecting different responses in the community to different disturbances and partly reflecting the vegetation status before disturbance.

Recovery after Experimental Cutting and Burning in Three Shrub Communities with Different Dominant Species

“…A good initial response was observed in this species after the fire, because heat stimulates its germination (GonzalezRabanal and Casal 1995;Webb 1998;. However, there was seedling mortality in the fourth year, probably due to the long period during which this species was under snow (Calvo et al 2002b). Vegetation dynamics in heathlands seem to depend on the interaction between species attributes and the climatic conditions in the area (Clement and Touffet 1981).…”

“…However, seeders can spread and colonize new microsites, whereas resprouters are restricted to the micro-sites previously occupied. On the other hand, Calluna vulgaris, which is an obligate seeder in these areas (Vera and Obeso 1995;Calvo et al 2002b), is the slowest to recover. A good initial response was observed in this species after the fire, because heat stimulates its germination (GonzalezRabanal and Casal 1995;Webb 1998;.…”

“…The speed of the dominant species recover, in the studied plots, conditions the dynamics of the plant community to a great extent. The slower recovery of Calluna vulgaris allows other woody species, like Vaccinium myrtillus and Erica tetralix, dominant throughout the study period in the burned and cut plots, respectively, to spread (Calvo et al 2002b). It also allows greater perennial herb cover.…”

“…It also allows greater perennial herb cover. Annual species cover is low, except in the burned plot in some years, and in these cases is due to a single species: Aira caryophyllea (Calvo et al 2002b). In contrast, the rapid recovery of Cistus ladanifer, especially after burning, restricts the proliferation of other species, so herbs have low abundance.…”

“…Climatic features are different in each area, but all of them had the common characteristic of being very homogeneous before disturbance, with only one shrub species clearly dominant, although a different one in each area (Calluna vulgaris, Erica australis and Cistus ladanifer). These communities have composed by three different shrub species with different recovery response: Erica australis is a facultative resprouter and recovers mainly by vegetative resprouting (Calvo et al 1998(Calvo et al , 2002a; while, Cistus ladanifer is an obligate seeder (LuisCalabuig et al 2000;Ta´rrega et al 2001) as is Calluna vulgaris in these areas (Calvo et al 2002b). Knowledge of the recovery dynamics of each community in relation to the type of disturbance is essential for suitable landscape management.…”