Monitoring Broadscale Vegetational Diversity and Change across North American Landscapes Using Land Surface Phenology

We describe a polar coordinate transformation of vegetation index profiles which permits a broad-scale comparison of location-specific phenological variability influenced by climate, topography, land use, and other factors. We apply statistical data reduction techniques to identify fundamental dimensions of phenological variability and to classify phenological types with intuitive ecological interpretation. Remote sensing-based land surface phenology can reveal ecologically meaningful vegetational diversity and dynamics across broad landscapes. Land surface phenology is inherently complex at regional to continental scales, varying with latitude, elevation, and multiple biophysical factors. Quantifying phenological change across ecological gradients at these scales is a potentially powerful way to monitor ecological development, disturbance, and diversity. Polar coordinate transformation was applied to Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) time series spanning 2000-2018 across North America. In a first step, 46 NDVI values per year were reduced to 11 intuitive annual metrics, such as the midpoint of the growing season and degree of seasonality, measured relative to location-specific annual phenological cycles. Second, factor analysis further reduced these metrics to fundamental phenology dimensions corresponding to annual timing, productivity, and seasonality. The factor analysis explained over 95% of the variability in the metrics and represented a more than ten-fold reduction in data volume from the original time series. In a final step, phenological classes (‘phenoclasses’) based on the statistical clustering of the factor data, were computed to describe the phenological state of each pixel during each year, which facilitated the tracking of year-to-year dynamics. Collectively the phenology metrics, factors, and phenoclasses provide a system for characterizing land surface phenology and for monitoring phenological change that is indicative of ecological gradients, development, disturbance, and other aspects of landscape-scale diversity and dynamics.

Report on winter crop plant-aphid- aphidophagous Chrysopidae (Neuroptera: Insecta) association from Murshidabad district, West Bengal, India

The enhancement of natural predators through habitat manipulation and increasing vegetational diversity can improve herbivore control. Aphids drew attention as they are serious phytosaccivorous pests and a threat against crop plants. Members of Family Chrysopidae (Neuroptera: Insecta) are proven biological control agents against aphids. Natural predators can bring down pesticide use against pest in a proper IPM (Integrated Pest Management) strategy. For this, identification of the existing pest, their natural predators and the pest host plant are necessary. This study deals with the field survey for aphids, aphid host plant and Chrysopidae species associated with aphids. This investigation may provide some essential basic information of occurrence aphids, their crop plant association and aphidophagous Chrysopidae. This may help to formulate an integrated pest management (IPM) strategy against aphid pest of crop plants in near future.

Vegetational Diversity Analysis across Different Habitats in Garhwal Himalaya

Four forest sites varying in vegetation types were studied along an altitudinal range between 2200 and 2500 m. Maximum tree, shrub, and herb species were recorded on stream bank site (22, 25, and 54, resp.). Pteridophytes and bryophytes species richness was maximum on moist site (4 and 5, resp.). The number of climbers was greater in moist and dry habitats (7 species each). Parasitic species were restricted only on dry and stream bank habitats. Restricted tree and shrub species were greater on stream bank site and dry site, respectively. The herb and climber species were greater on moist site. The distribution and species richness pattern in this elevational range largely depend on the altitude and climatic variables. Along the entire range of Garhwal Himalaya, the overlapping among species regimes is broad; therefore, transitional communities having mixture of many species and zones are present. The present study indicates that the opening canopies increase the richness of tree, shrub, herb, and climbers.

Mastodon herbivory in mid-latitude late-Pleistocene boreal forests of eastern North America

Skeletal remains of the extinct American mastodon have often been found with deposits of short, decorticated twigs intermixed with plant fragments presumed to be gastrointestinal or fecal material. If such deposits are digesta, paleobotanical evidence may be used to analyze mastodon foraging strategy, with implications for assessing habitat selection, ecological roles, and response to environmental change. To identify components of mastodon diet in mid-latitude late-Pleistocene boreall forests of eastern North America, plant macrofossils and pollen from a molar socket (Hyde Park site, New York) were compared with dispersed deposits associated with skeletal remains (Hiscock and Chemung sites, New York). Similar macrofossil condition and twig morphology among samples, but difference from a modern boreal fen analog, confirmed the deposits were digesta. Comparison of twigs with material from other paleontological sites and modern elephants suggested dimensions generally indicative of digesta. Picea formed the bulk of each sample but Pinus may have been locally important. Wintertime browsing of Salix and Populus, and springtime consumption of Alnus, were indicated. Evidence for Cyperaceae, Gramineae, and Compositae was ambiguous. If conifers, broadleaf trees, shrubs, and herbs were necessary to fulfill dietary requirements, mastodons would have been nutritionally stressed by rapid late-Pleistocene decrease in vegetational diversity.

Interpreting pollen diagrams from wetlands: pollen representation in surface samples from Oil Well Bog, southern Ontario

Pollen and spore analysis of surface sediment samples from 45 points within Oil Well Bog, a coniferous swamp near Cambridge, Ontario, was used to determine the possibility of identifying different wetland vegetation communities from their palynological record, and to assess the effects of variable wetland vegetation on the pollen representation of surrounding upland communities. The data obtained were mapped for individual taxa to allow direct comparison of the spatial patterns of vegetation abundance and the associated palynological assemblages, and cluster analysis was used to identify palynologically similar assemblages. Some wetland communities, such as swamp dominated by black spruce, do have distinctive pollen signatures, but not all the vegetational diversity observed is reflected in the palynological data, with similar pollen assemblages deriving from some communities which are vegetationally very different (e.g., shrub swamps dominated by Chamaedaphne calyculata and Ilex verticillata). The wetland pollen assemblages do reflect much of the floristic diversity of the surrounding uplands, although the different communities receive varying proportions of their pollen influx from upland sources (varying from less than 5% to over 90%), and wide variations in the percentage of a given upland pollen morphotype can be found within quite a short distance, depending on the nature of local wetland communities.Key words: palynology, swamp, surface samples, wetland.