Nasrullah Khan

Vegetation-environment relationships in the forests of Chitral district Hindukush range of Pakistan

We investigated the composition of plant communities to quantify their relationships with environmental parameters in the Chitral Hindukush range of Pakistan. We sampled tree vegetation using the Point Centered Quarter (PCQ) method while understory vegetation was sampled in 1.5-m circular quadrats. Cedrus deodara is the national symbol of Pakistan and was dominant in the sampled communities. Because environmental variables determine vegetation types, we analyzed and evaluated edaphic and topographic factors. DCA-Ordination showed the major gradient as an amalgam of elevation (p<0.05) and slope (p<0.01) as the topographic factors correlated with species distribution. Soil variables were the factors of environmental significance along DCA axes. However, among these factors, Mg2+, K+ and N2+ contributed not more than 0.054% 0.20% and 0.073%, respectively, to variation along the first ordination axis. We conclude that the principal reason for weak or no correlation with many edaphic variables was the anthropogenic disturbance of vegetation. The understory vegetation was composed of perennial herbs in most communities and was most dense under the tree canopy. The understory vegetation strongly regulates tree seedling growth and regeneration patterns. We recommend further study of the understory vegetation using permanent plots to aid development of forest regeneration strategies.

Future of Abies pindrow in Swat district, northern Pakistan

Swat district is a biodiversity hub of Pakistan. The plant species, especially trees, in the Swat District are exposed to extinction threat from global climate change. Maximum entropy (MaxEnt) modelling of species distribution, using HADCM3 A2a global climate change scenario, predicted a considerable change in the future distribution of Abies pindrow (Royle ex D.Don) Royle. AUC (area under the curve) values of 0.972 and 0.983 were significant for the present and future distribution models of the species, respectively. It is clear that bioclimatic variables such as the mean temperature of the warmest quarter (bio_10) and the annual temperature range (bio_7) contribute significantly to the model and thus affect the predicted distribution and density of the species. The future model predicts that by the year 2080 population density will have decreased significantly. The highest density of the species is recorded in the eastern and western borders of the Valley in the areas of Sulatanr and Mankial. The changes in density and distribution of the species can have considerable impact, not only on the tree species itself, but on the associated subflora as well.

Phytosociology, structure and dynamics of Pinus roxburghii associations from Northern Pakistan

We investigated the phytosociology, structure and dynamics of Pinus roxburghii in 40 stands in northern areas of Pakistan by using cluster analysis (Ward’s agglomerative clustering) and ordination (Nonmetric Multidimensional Scaling). Cluster analysis revealed three major groups associated with specific environmental characteristics: (1) P. roxburghii (2) Pinus-Quercus baloot and (3) Pinus-Olea ferruginea community types. NMS-ordination showed the major gradient as an amalgam of elevation (r2 = 0.441, p <0.01) and slope (r2 = 0.391, p <0.05) as the two topographic factors correlated with species distribution. The first ordination axis also showed positive correlation with soil variables like pH and electrical conductivity, suggesting that soil chemistry was related to topographic characteristics and probably acted as a secondary gradient. We also examined size class distributions, age structures and growth rates of the three communities in order to describe community development and dynamics. Total tree density was 14700 plants/ha, with P. roxburghii having a relative density of 82% to 100%. Density of juvenile and total density and basal area of the subordinate tree species were low. The low density of trees in the smallest diameter size-class suggested that the recruitment of small P. roxburghii plants into the adult population may be lower than the required replacement rate for the stands. Pooled size-class distributions for the species showed a multimodal pattern with some regeneration gaps. Browsing, heavy logging and other anthropogenic activities were the overriding factors responsible for the poor recruitment of P. roxburghii. We concluded from the age structure that the forests were characterized by the dominance of young trees. Growth rate analysis revealed that P. roxburghii was the fastest growing species among the conifers species in Pakistan. In view of its relatively fast growth and longevity, P. roxburghii seems to be a suitable choice for short-term cultural practices in order to enhance wood production in lesser Himalaya and Hindukush ranges of Pakistan.

Climatic signal in tree-ring chronologies of Cedrus deodara from Chitral Hindukush Range of Pakistan

Tree-rings are an important tool for the investigation of paleoclimatic records for regions or periods of time with no instrumental climatic data. However, the responses of different species and sites to various climatic parameters are unusual. In the present study, we developed tree-ring-width chronologies of Cedrus deodara from three different sites of Chitral Hindukush range of Pakistan. The study was conducted to understand tree-growth climate relationship and its applicability in proxy climate investigations. The chronologies covered the past 469 to 595 years, with a mean segment length (MSL) ranging from 148 to 223 years. Climatic data obtained from the three weather stations showed strong correlation and was found useful for tree-ring climate relationships.Correlation Function (CF) and Response Function (RF) analysis showed that spring precipitation (March–May) is a critical limiting factor for tree-ring growth, and temperature prior to November may also play a major role in affecting tree ring-growth. The results exposed that the three sites have continuous relationship indicated that only single species from different locations are affected by the same environmental variables and hence can be used in climate reconstruction in combination. The Cedrus deodara chronologies developed at different locations had several corresponding narrow and wide marker rings indicating a large macroclimatic response to regional climatic conditions. The current study suggests that the tree-rings of Cedrus deodara from the Chitral Hindukush range could be used to develop chronologies for the reconstruction of seasonal climatic variables.

Six Centuries of Upper Indus Basin Streamflow Variability and Its Climatic Drivers

Our understanding of the full range of natural variability in streamflow, including how modern flow compares to the past, is poorly understood for the Upper Indus Basin (UIB) because of short instrumental gauge records. To help address this challenge, we use Hierarchical Bayesian Regression (HBR) with partial pooling to develop six centuries long (1394-2008 C.E.) streamflow reconstructions at three UIB gauges (Doyian, Gilgit, and Kachora), concurrently demonstrating that HBR can be used to reconstruct short records with interspersed missing data. At one gauge (Partab Bridge), with a longer instrumental record (47 years), we develop reconstructions using both Bayesian Regression (BR) and the more conventionally used Principal Components Regression (PCR). The reconstructions produced by PCR and BR at Partab Bridge are nearly identical and yield comparable reconstruction skill statistics, highlighting that the resulting tree-ring reconstruction of streamflow is not dependent on the choice of statistical method. Reconstructions at all four reconstructions indicate flow levels in the 1990s were higher than mean flow for the past six centuries. While streamflow appears most sensitive to accumulated winter (January-March) precipitation and summer (MJJAS) temperature, with warm summers contributing to high flow through increased melt of snow and glaciers, shifts in winter precipitation and summer temperatures cannot explain the anomalously high flow during the 1990s. Regardless, the sensitivity of streamflow to summer temperatures suggests that projected warming may increase streamflow in coming decades, though long-term water risk will additionally depend on changes in snowfall and glacial mass balance.

The ethnobotanical domain of the Swat Valley, Pakistan

BackgroundThis study contributes to the current ethnomedicinal knowledge of the Swat Valley, Pakistan. District Swat possesses remarkable biodiversity owing to its varied topographical and climatic conditions, prompting a distinct human-plant association. Our hypothesis is that the presence of such a great biodiversity has shaped into a formal ethnobotanical culture in the area transmitted through generations. We suspect that the versatility of some plant species has greater influence on the culture. Therefore, the prime objective of the study is to understand this unique human-plant relationship in the valley and to create scientific roots for the selection and practice of herbs in the ethnobotanical domain of the district.MethodsPrimary data were collected using questionnaires and face-to-face interviews with the locals. The data collected were used for calculating some important indices, i.e. relative frequency of citation (RFC), participant agreement ratio (PAR), frequency of citation (FC), Smith’s Salience Index (SI), Relative Importance Index (RII), Cultural Value Index (CVI) and a newly proposed, Ali’s Conservation Priority Index (CPI). Index scores were used as key identifier of the ethnobotanically important plants of the area.ResultsResidents of the Swat Valley have listed plant uses in 15 use categories. Around 9% of the respondents have a common consensus on the selection and use of plants for the treatment of evil eye with similar results for body cuts (8.2%) followed by psychological/neural ailments (8.0%). Respondents agree that Berberis lyceum Royle. dominates in all five indices. Skimmia laureola Franch. also constitutes one of the central plants of the ethnobotanical domain, ranking second in the SI, fifth in the RII, seventh in CVI, and third in the Cultural Importance Index. It holds the thirty-fifth position in the CPI. Over 80% of the population treat different diseases with herbal remedies. In the common ethnobotanical domain of the area, plants like Mentha longifolia L., Berberis lyceum, and Skimmia laureola are very important and have high salience and importance values, thus suggesting these plants are versatile for their uses in the study area.ConclusionIn conclusion, only some plant species are prioritised for their use in the ethnobotanical domain of the community. Medicinal and aromatic plant (MAP) usage is widespread in the Swat Valley. The ethnobotanical knowledge could be used as a tool to understand the adaptability of a specific taxon in the area and the possible conservation risk to their existence.

The influence of environmental variables on Punica granatum L.assemblages in subtropical dry temperate woodland in the districtof Lower Dir, Khyber Pakhtunkhwa, Pakistan

Punica granatum L. (Wild) is an important fruit-yielding species of the world and a source of income for people, particularly in the Hindukush-Himalayas of Pakistan. Considering its ecological and commercial importance, an attempt was made to provide a primary assessment of its compositional pattern with relation to environmental variables for ecologically unexplored Punica granatum forests located in a subtropical dry temperate zone using multivariate techniques. The vegetation data were collected from 40 Punica granatum forest stands along with the associated environmental data (12 variables) at different locations. Classification of the stands was carried out using Ward?s agglomerative cluster analysis. In total, 20 tree species belonging to 13 families of 19 genera with 78 understories were surveyed. Finally, nonmetric multidimensional scaling ordination with associated Monte Carlo permutation tests was performed to explore the patterns of variation in vegetation distribution explained by the environmental variables. Four community types were identified in different altitudinal and microclimatic thickets that significantly varied in species composition. The soil physical properties, i.e. sand and clay, forming an amalgam with chemical properties, i.e. N+1 and K+1 concentrations, were the most influential variables responsible for distribution of Punica granatum and associated species and compositional variation in the subtropical dry temperate areas of Pakistan. The present study will help in the understanding of conservation and management of this ecologically and commercially important species and will provide baseline information for other forests species growing in the area.