The subtropical broadleaved humid forest of Meghalaya, northeast India are characterised by small remnant patches. The major threats to the existing patches are anthropogenic activities such as encroachment of forest area, mining, extraction of forest resources, grazing and forest fire. The present study was carried out at Jarain and adjoining areas of Jaintia Hills in Meghalaya, northeast India to identify the current human disturbances and assess the floristic composition and structure of subtropical broad leaved forest along a fragment size gradient. Floristic sampling was carried out by laying 24 plots (20mx100m) across 10 forest fragments covering a sampled area of 4.8 ha. A total of 160 woody species (≥5cm dbh) belonging to 105 genera and 54 families were enumerated from all the studied fragments. The species richness was 69 in Small, 75 in Medium, 76 in Very Large (VL) and 77 in Large (L) fragment classes. In this study, Pearson's correlation analysis was performed to analyse the relationship between area, disturbance and phytosociological attributes. The results showed that the stand density increased (r = 0.71, p=0.01), while basal area decreased with disturbance (r = -0.74, p= 0.01). The density was high in 5-15cm dbh class that gradually declined with the increase in diameter. The basal area was high in >66cm dbh class in Very Large fragments whereas in small patches, the values were higher in 16-25cm dbh classes. The forests fragments under study also have a number of rare, endemic and threatened species. Therefore, it is suggested that the entire landscape be brought under the protected area network due to high species diversity.
<p><em>Magnolia lanuginosa</em> (Wall.) Figlar & Noot. [= <em>Michelia</em><strong> </strong><em>lanuginosa</em> Wall.], a rare tree species of Meghalaya, is restricted to the West Khasi Hills District, Meghalaya. The species was considered to have become extinct from the state. The present paper reports a recent re-collection of the species from four locations in the West Khasi Hills after a lapse of almost 100 years. In addition, the population structure, regeneration status and the threat to the species are also discussed so as to develop effective strategies for its conservation. </p><div> </div>
Aim of the study: The aim of the study was to assess the seasonal dynamics of microbial biomass and its contribution to soil system along a fragment size gradient in subtropical humid forest of Meghalaya. Area of study: The study was conducted in forest fragments located at Jarain and adjoining areas in Jaintia Hills of Meghalaya, northeast India.Material and Methods: Forest fragments of sizes ranging from 3.8 to 105 ha were selected for the study and grouped into Small (< 5 ha), Medium (> 5 and < 15 ha), Large (>15 and < 50 ha) and Very Large (105 ha) classes. Three experimental plots each of 20 x 20 m were established at the forest edge and at 50 m distance assigned as ‘interior’ microsite in each of the fragments for sampling of soil. Soil samples (0-10 cm depth) from each of the experimental plots were collected in replicates on seasonal interval and microbial biomass was estimated by the fumigation extraction method.Important findings: Microbial biomass- C, -N and -P varied significantly (p< 0.05) between the fragment sizes, microsites and seasons. The microbial biomass was higher in the interior as compared to the edge. It was also high during the winter season. Overall, soil microbial biomass -C, -N and -P ranged from 260 to 969; 25 to 95 and 8 to 67 µg g-1 respectively. The contribution of microbial biomass -C, -N and -P to soil organic carbon, total Kjeldahl nitrogen and phosphorus ranged from 1.48 to 1.81 %, 2.54 to 4.54 % and 3.41 to 5.22 % respectively. Fragmentation alters the microenvironmental conditions and soil properties that in turn affect the microbial biomass. Highlights: This interaction of plant, soil and microbial community would gradually degrade in the fragments due to change in vegetation composition and structure, microclimatic conditions and soil physical and chemical properties. Our results suggests that microbial mediated ecosystem processes such as nutrient cycling are more susceptible to variation at the edge which may become unstable and unpredictable in forest fragments exposed to various human disturbances.Keywords: fragment size, microbial biomass, microenvironment, subtropical forest.
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