Climatic and flowering phenological relationships of western Himalayan flora of Muzaffarabad district, Azad Jammu and Kashmir, Pakistan.
Anthropogenic climate change is influencing many aspects of biodiversity hotspot of the western Himalaya. Muzaffarabad district as part of western Himalayan is a strongly seasonal area, thus studies on interrelationship of timing of phenological periodic events and climatic seasonality is of obvious significance. A first ever detailed eco-taxonomical field survey of the whole district was conducted to explore floral diversity, plant habit associated with microhabitats. Timing of flowering response of species within the different months was also recorded during two consecutive years (2014-16) and flowering phonological data was stored as binary data matrix. The influence of studied climatic variables on the flowering phenological response was tested through canonical correspondence analysis (CCA). A total of 748 vascular plants (740 species, 3 sub-species, 5 varieties) belonged to 490 genera and 120 plant families were recorded including 77 species as new to the study area. The leading plant family was Compositae (69 spp., 9.22%), followed by Poaceae (57 spp., 7.62%), Leguminosae (54 spp., 7.22%), Lamiaceae (42 spp., 5.61%) and Rosaceae (29 spp., 3.88%); while the leading genus was Euphorbia (10 spp.), followed by Cyperus, Ficus, Geranium and Prunus (7spp. each). With respect to life forms, perennial herbs were the most dominant (297 spp., 39.71%), followed by annual herbs (188 spp., 25.13%). With reference to diversity of microhabitats, coniferous forest was leading in terms of floristic diversity having 243 species (32.10% of total flora), followed by drier slopes, home gardens (158 spp., 20.87% each), arable land (143 spp., 18.89%) and waste places (122 spp., 16.12%). The majority of plant species found in flowering stage during July and August months (473 spp., 62.48% and 458 spp., 60.5% respectively), while the least ones during January (51 spp., 6.73%) and December (55 spp., 7.26%). Results of CCA showed that total variations in the response data were 1.742 and 71.8% were explained by the explanatory variables. Based on conditional (net) term effects, mean monthly minimum temperature was detected as the most important and significant [pseudo-F 4.3; p(adj) 0.005] towards explaining the variations in the flowering response data. It was followed by wind speed [pseudo-F 2.9; p(adj) 0.0225] and relative humidity [pseudo-F 2; p(adj) 0.04625] variable. Interestingly, July and August months not only receive maximum rainfall but also majority of species flowered in these months, but CCA results confirmed that rainfall is not important predictor with respect to species flowering response event in the area. It was concluded that the flora of the study area was more influenced by the climatic factors like temperature, wind speed and relative humidity. This Himalayan region is fragile and rapid temperature rise could lead to catastrophies like wiping out of endemic and endangered species, earlier snowmelts and resultant earlier blooming causing invasive species spread, upwards timber-line shift and rapid changes in vegetation composition. This baseline study information could be used to deal these issues and need to have effective regional collaboration of scientific community and policy makers is recommended.