Ecological and Geoinformatics Evaluation of Vegetation Dynamics in the Murree Forests; a step towards Biodiversity Conservation

Abstract

It is imperative to understand floristic composition, structure and spatial distributions and its underlying mechanisms at species, community and ecosystem levels. The current research work was conducted during 2016-2020 to evaluate the plant resources and vegetation dynamics of the Murree Forest Division (MFD), ecologically. The main aim of the current study was to evaluate and confirm that climate change has considerable impacts on the vegetation cover and dynamics triggered by urbanization in the hilly areas of MFD over the past few decades. Overall findings of the current dissertation are broadly presented in three steps i.e., species and community level dynamics, digital elevation modelling, biotic interactions (climbers as indicators), vegetation cover dynamics over the last four decades and syntheses. Phytosociological characteristics of the individual plant species were measured using the quadrats (498 in total) along the elevation transects (166 in total) via stratified random sampling design. Soil samples were taken and analyzed for their physiochemical properties. All the quantitative ecological data of plant species were analyzed for density, cover and Importance Value Index and then arranged according to the requirements of PCORD & CANOCO softwares. Multivariate statistical analyses were used to find the relationships between vegetation diversity, soil factors, topography and biotic factors. Preliminary findings confirmed 454 plant species distributed among 98 families and 176 genera recorded in the 494 quadrats. Taxonomically, Poaceae was the most abundant family followed by Asteraceae, Papilionaceae, Lamiaceae and Rosaceae. The dominant life forms were the Therophytes and Nanophanerophytes. Therophytes is one of the life forms that is having the ability to cope with adverse environmental circumstances via producing seeds for the harsher period of its life cycle. Nanophyll and Microphylls were the dominant leaf forms in the MFD. Various environmental variables that is the elevation, slope, soil texture, pH, organic matter, canopy, nitrogen and grazing pressure significantly affect the species distribution, composition and community classification (P-value ≤ 0.05). The application of classification and ordination techniques (multivariate analyses) broadly divided the Murree forest vegetation into five major plant communities/associations viz., 1) Picea smithiana, Spiraea canescens, Trifolium spp, 2) Quercus robur, Rubus fruticosus, Cyperus rotundus, 3) xxi Salix babylonica, Buddleja crispa, Potentilla reptans, 4) Pyrus bourgaeana, Reinwardtia indica, Gentiana olivieri and 5) Lannea coromandelica, Buxus papillosa, Phyla nodiflora community. Knowledge about climber species in the forests is relatively inadequate and the current study provides the first report on the climber species of MFD Pakistan. Climbers were focused specifically, in relation to their host as a baseline reference for possible future dynamics. Overall 3400 individuals of climbers belong to 23 species, 19 genera and 13 families were identified. Climber species are classified into four classes based on their habit. The dominant class was represented by twining climbing mode followed by woody and hook mode. The abundance and distribution of climber plants were affected by parameters like biotic factors (grazing pressure and number of hosts) and abiotic factors (topographic and edaphic). Canonical Corresponding Analysis indicated that grazing and collection pressures along with elevation were the most important factors influencing the distribution and abundances of climbers. Mapping of vegetation via ArcGIS was done to know the overall vegetation dynamics in the MFD over the last 4 decades. The whole MFD was then divided into five elevation classes namely, uppermost class (1901–2258 m), upper class (1601– 1900 m), medium elevation class (1301m–1600m), lower class (1001–1300 m) lowest class ranges (519–1000 m) and showed via the Digital Elevation Models (DEM) maps. The effect of climate change (designated in terms of rainfall and temperature) on vegetation (designated in terms of Normalized Difference Vegetation Index; NDVI) and forest cover in the MFD were also assessed. Rainfall and Temperature data of nearest weather stations; vegetation and forest cover (consequent using 1988, 1998, 2008, 2018 years‟ data from Landsat imageries series i.e. 5 TM, 7 ETM, 8 OLI by using ArcGIS and ERDAS Imagine) were used in the investigation for both the pre-monsoon and post-monsoon seasons. The simple regression method was used to assess the relationship of climate change factors with NDVI and forest cover in this study. During the pre- monsoon season, forest cover and temperature analysis indicated high regression coefficient rate and vegetation (NDVI) and temperature analysis showed regression coefficient moderate rate. Furthermore in the post monsoon season investigation forest cover and rainfall showed regression coefficient rate of 0.4959 and vegetation index (NDVI) and temperature displayed regression coefficient rate of 0.7338. The study revealed that temperature was significantly xxii correlated with forest cover and vegetation in pre-monsoon season however In post monsoon season rainfall demonstrated positive response to forest cover, and temperature showed negative response to vegetation index in the Murree forests. The results demonstrated that vegetation is reducing in the MFD, Pakistan. In summary the current study apart from answering numbers of ecological questions provides a baseline for future studies of vegetation dynamics and climate change studies. It provides a record for monitoring forest cover changes over space and time and evaluation of the climate changes and anthropogenic pressures for long term management at species, habitats, and ecosystem levels in at the western Himalayas.