Regeneration strategy and plant diversity status in degraded sal forests

Abstract

The degraded sal forests of north-eastern Uttar Pradesh were observed for the regeneration strategy of co nstituent woody perennials and the status of r esultant plant diversity. The species showing poor sprouting were much greater in number at low disturbance. Conversely, the species showing rich sprouting and ramet formation were much more at high disturbance. The diversity index ) (H was always greater when a genet complex was treated as a single individual than in case when each ramet, distinct at soil su rface, was treated as a separate individual. The value of , H however, was lower at low disturbance. It is a moot point whether the diversity index should be based on the number of genets (biotypes) or superficially di stinct shoots (including ramets) irrespective of their genetic status. The species like Clerodendron infortunatum, Croton oblongifolius, Mallotus philippensis and Flacourtia indica increased their ramet production with increase in disturbance level, but recurrent di sturbance of high intensity affected ramet proliferation quite adversely. Bridelia retusa, Casearia tomentosa and Holarrhena antidysenterica produced comparatively much lesser number of ramets per genet. The inter-ramet distances or spacers on root -stock as well as the number of ramets per genet showed significant differences with respect to the level of disturbance. The age structure and spatial pattern of ramet population were also correlated with the level of disturbance. In a forest environment which is too harsh to allow regeneration through seed, a non -seed regeneration of a group of woody perennials may help maintain the minimal vegetation cover and considerable plant diversity. The non-seed regeneration strategy of pr olific ramet producers, therefore, shows a promise to the quick recovery of forest ecosystems ravaged by anthropogenic perturbations. SEED germination and vegetative propagation are the two major modes of regeneration in pe rennial plants. The morphological units in the form of vegetative offshoots, initially physically a ttached to the parent plant but cap able of ind ependent existence are called ramets, while a genet is a plant of seed origin irrespective of the nu mber of sprouts and/or ramets originating from it 1 . All parts of the genet share exactly the same genes. As in many perennial herbs, a number of woody plants also show cont inuity of root-stocks in the form of inter -ramet connections which make the genet a physiologically integrated sy stem. The phenomenon is well documented in several perennial herbs