CLOUD DROP SPECTRA IN MARITIME AND INLAND REGIONS

Measurements o f clo ud drop ..ire spectra on non-preci pitating cumulus clouds, 1·2 km thick,were made at differe nt levels o ver the Arabian Sea (maritime) and over r une (inland) regio n during the end ofthe summer monsoo n seasons of 1973, 1974 and 1979.The macimurn size of clo ud drops for the. Arabian Sea generally increased with height. while that for run eJiJ not show a systematic change with height. At bot h the local ions. the total concentration o f drops decreasedwith height. The maritime dist ributions were bimodal at all levels while those o..-er Punc were usually unimodal.The average values of liquid water content. mean vo lume diameter. dispersion and conccnt rarion of drops withdiameter > 50 «m were a lin le greater and total concentration a little smaller over the maritime region as ' om'pared to those over inland. The co ncentrations of drops with diameter < 14 ,...m and those > 78 I'm and thema ximum ~ i 7e were greater over Pune than o..er the sea. The ..'a riarions in cloud drop spectra and the clo udphysical parameters over beth the locations are discussed.Kc) words - Cloud drop size spectra, Drop co ncentration,

FLORISTIC COMPOSITION AND BIOLOGICAL SPECTRUM OF BARA GALI, ABBOTTABAD

Floristic composition and Phytosociological studies on the flora of Bara Gali District Abbottabad, Pakistan was conducted. The altitudinal range of the Bara Gali is from 2100-2370 meter. From the study area 50 species belong to 33 families were recorded. Herbaceous flora was dominant with 35 species, shrubs with 10 species and tree with 5 species. Asteraceae was dominant having 6 species. Microphyll dominant leaf size spectra and hemicryptophytes were dominant life form in the study area. This study provide information about the floristic composition of Bara Gali.

Classification and Characterization of the Manoor Valley’s (Lesser Himalaya) Vegetation from the Subtropical-Temperate Ecotonal Forests to the Alpine Pastures along Ecological Variables

Plant species are distributed in different types of habitats, forming different communities driven by different sets of environmental variables. Here, we assessed potential plant communities along an altitudinal gradient and their associations with different environmental drivers in the unexplored Manoor Valley (Lesser Himalaya), Pakistan. We have implemented various ecological techniques and evaluated phytosociological attributes in three randomly selected 50 m-transects within each stand (a total of 133) during different seasons for four years (2015–2018). This phytosociological exploration reported 354 plant species representing 93 different families. The results revealed that the Therophytic life form class dominated the flora, whereas Nanophyll dominated the leaf size spectra. There were a total of twelve plant communities identified, ranging from the lowest elevations to the alpine meadows and cold deserts. The maximum number of species were found in Cedrus–Pinus–Parrotiopsis community (197 species), in the middle altitudinal ranges (2292–3168 m). Our results showed that at high altitudes, species richness was reduced, whereas an increase in soil nutrients was linked to progression in vegetation indicators. We also found different clusters of species with similar habitats. Our study clearly shows how altitudinal variables can cluster different plant communities according to different microclimates. Studies such as ours are paramount to better understanding how environmental factors influence ecological and evolutionary aspects.

Spatiotemporal variability of abundance size-spectra in streams across North America

Accepted version of this manuscript can be found here: https://doi.org/10.1111/gcb.15862 The distribution of abundance and biomass within ecological communities is related to trophic transfer efficiency from prey to predators. While it is considered to be one of the few consistent patterns in ecology, spatiotemporal variation of this relationship across continental-scale environmental gradients is unknown. Using a database of stream communities collected across North America (18-68° N latitude, -4 to 25°C mean annual temperature) over 3 years, we constructed 162 mass-abundance relationships (i.e. size spectra). Size-spectra slopes declined (became steeper) with increasing temperature. However, the magnitude of change was relatively small, with median slopes changing from -1.2 to -1.3 across a 29°C range in mean annual temperature. In contrast, total community biomass increased 3-fold over the temperature gradient. Our study suggests strong conservation of abundance size-spectra in streams across broad natural environmental gradients. This supports the emerging use of size-spectra deviations as indicators of ecosystem health.

Response of Zooplankton Size Structure to Multiple Stressors in Urban Lakes

Urban lakes are important environmental assets that contribute significant ecosystem services in urbanised areas around the world. Consequently, urban lakes are more exposed to anthropogenic pressures. Zooplankton communities play a central role in lake processes and, as such, are very sensitive to the impacts of human activities both through in-lake and catchment processes. Understanding their ecological function in urban lakes and how they respond to urbanisation is essential for environmental sustainability. In this study, we investigated the reliability of zooplankton size structure as indicators of anthropogenic stressors in urban lakes. We examined the relationship between environmental variables and zooplankton community size spectra derived as mean body size, density, and biomass. Our study showed that the overall mean body size was within the small size group ranged from 416 to 735 µm equivalent spherical diameter (ESD). Despite no significant difference in total zooplankton density between lakes, there was variability in the total density of the five different size classes. Total biomass was characterised by a significant proportion of size >750 µm. As the specific parameter of normalised biomass size spectra (NBSS), the slopes of the NBSS varied from moderate (−0.83 to −1.04) for a community with higher biomass of the larger size zooplankton to steeper slopes (from −1.15 to −1.49) for a community with higher biomass of smaller size. The environmental variables, represented by total phosphorus (TP) and chlorophyll a (chl-a), had a strong effect on zooplankton biomass and NBSS, where TP and chl-a were significantly correlated with the increase of total biomass and corresponded well with a less negative slope. Our results indicated that the community metric was sensitive to nutrient input and that size-based metrics have the potential to serve as key indicators for the management of urban lakes.