Malham's Vascular Plants - Rarity, Vulnerability and Candidates for Long Term Monitoring

Monitoring of rare species is a common feature of nature reserves. It can help identify quantitatively the effects of habitat management (such as grazing regime), local changes (eg. scrub development) or broader changes (eg climatic effects). A notable success of British conservation has been the Butterfly Monitoring Scheme which has enabled local and national influences on a species to be understood (Brereton et al, 2006). By contrast to butterflies long term monitoring of plant species is difficult to standardise. This is due to the various factors that can be recorded (eg. no. of individuals, degree of cover etc.), these in turn being a product of the various growth forms and reproductive patterns of vascular plants. In an attempt to bring some order to plant monitoring Menges and Gordon (1996) identified three basic levels of monitoring; Level 1 identifies species occurrence and the area of occurrence; Level 2 identifies a measure of abundance based and Level 3 involves demographic monitoring of particular individuals such as that employed by Hutchings (1987) on Ophyris sphegodes. With its combination of relative isolation, climate, geology, soils and relatively long history of protection Malham has many vascular plant species of conservation significance, although the dynamics of these species is poorly understood. Hence initiation of Long Term Monitoring (LTM) on at least some of these species is worthy of consideration. Following the mapping of British plant species by Perring and Walters (1962) the degree of rarity of each member of the British flora has been categorised using distribution. Rare plants are present in 15 or less hectads nationally and scarce plants are present in 16-100 hectads nationally. These rare plants have been described by Perring and Farrell (1977, 1983) and Wiggington (1999), while scarce plants have been described by Stewart et al (1999). These lists have been recently reviewed by Cheffings (2004). A different approach has been taken by Cheffings and Farrell (2005), who produced a Red List for the British flora based upon the rate of decline and international distribution. This allocated members of the British flora to IUCN categories of conservation importance. Malham has a number of plant species which are designated scarce or rare or fall into IUCN categories. These species may be appropriate for LTM. The aim of this paper is to confirm which rare and scarce plants are at Malham; to identify which plants with significant IUCN categories are at Malham and from these lists to identify which species could be suitable for LTM based upon the criteria of access, safety, life history and abundance.