Percentage Of Vegetation Research Articles

Assessing the potential of Sentinel-2 MSI sensor in detecting and mapping the spatial distribution of gullies in a communal grazing landscape

In this study, we evaluate the potential of the recently launched Sentinel-2 MSI multispectral sensor in mapping the spatial distribution of gullies in Okhombe valley, KwaZulu-Natal, South Africa. The study further investigates possible environmental factors that contribute towards gully initiation and development. Analysis was done using a robust machine learning algorithm: Support Vector Machine (SVM). Additionally, possible environmental factors (i.e. slope steepness, percent vegetation cover, and Topographic Wetness Index, Stream Power Index, and hillslope profile and planform curvature) that could have an influence on the extent of the gullies were also derived. An overall land cover classification accuracy of 94% was achieved, while the overall classification accuracy for gullies was 77%. It was observed that bands located in the visible regions of the EM, red edge and SWIR could optimally discriminate gullies from other land cover types. Additionally, the findings of the study indicate no significant difference between the environmental variables across the different estimated gully volumes and indicate a weak correlation between the variables of R = 0.190526. Overall, the findings of the study demonstrate the importance of using the free and readily available multispectral Sentinel-2 MSI data in conjunction with robust non-parametric Support Vector Machine classifier in mapping the spatial distribution of gullies.

Using orthoimages generated from oblique terrestrial photography to estimate and monitor vegetation cover

Percent vegetation cover is important variable used in understanding ecosystem processes, vegetation health and productivity. Downward looking images captured using a handheld camera have been demonstrated as a viable option for rapidly capturing in situ information to assess vegetation cover. This technique, however, is prone to perspective distortions biasing cover estimates towards taller vegetation elements. In this paper we present a new approach to generate imagery for use in vegetation cover estimation utilising multiple overlapping photographs and structure from motion algorithms to produce a 3D point cloud representation of the target plot. This point cloud is then converted into an orthoimage consisting of four bands—red, green, blue and vegetation height—which is free from perspective distortions. The approach is trialled in two Eucalypt forests in South Eastern Australia to produce an estimate of change in cover of all vegetation elements following a prescribed burn. Orthoimages are generated with 2.5 mm resolution and classified using object-based image analysis and random forests into broad vegetation and fuel classes. Utilising this approach an overall classification accuracy of 81% is achieved with the resulting estimates of cover agreeing with visual point based interpretation to within 6% across all classes.

Habitat and landscape factors influence pollinators in a tropical megacity, Bangkok, Thailand.

BackgroundPollinators are well known for the ecosystem services they provide, and while urban areas are generally perceived as low-quality habitat for most wildlife, these cities often support a surprising degree of pollinator diversity. The current rapid growth of urban areas and concern over global pollinator declines have spurred numerous studies examining pollinator communities in temperate cities, but knowledge about tropical urban pollinators remains scarce.MethodsThis study investigated the effects of habitat and landscape factors on pollinator richness and abundance in a highly-populated, tropical city: Bangkok, Thailand. We conducted pollinator observations in 52 green areas throughout the city and collected data on patch size, floral abundance, plant richness, location type, and percent vegetation at five spatial scales.ResultsOf the 18,793 pollinators observed, over 98% were bees. Both patch size and floral abundance generally had positive effects on pollinators, although there was a significant interaction between the two factors; these findings were generally consistent across all focal taxa (Tetragonula stingless bees, Apis honey bees, Xylocopa carpenter bees, and butterflies).DiscussionOur results demonstrate the importance of maintaining large green areas in cities, since small green areas supported few pollinators, even when floral resources were abundant. Moreover, most pollinator taxa utilized a variety of location types (e.g., public parks, school campuses, temple grounds), with the exception of butterflies, which preferred parks. Our findings are generally consistent with those of temperate urban studies, but additional studies in the tropics are needed before global patterns can be assessed.

Long‐term impacts of shrub plantations in a desert–oasis ecotone: Accumulation of soil nutrients, salinity, and development of herbaceour layer

AbstractThis study used a 40‐year chronosequence of Haloxylon ammodendron plantations to evaluate its impacts on soil and vegetation conditions in a desert–oasis ecotone with extremely low annual precipitation (≈100 mm). We found that the fraction of silt and clay contents significantly increased from 6.4% and 5.1% in Year 0 to 22–23.3% and 15.8–18% in the 40‐year‐old plantation in the soil depths of 0–10 and 10–20 cm, respectively. Soil nutrients (i.e., soil organic matter, total nitrogen, and total phosphorus) were significantly improved after H. ammodendron plantations. However, there was a significant increase in soil salinity, which may negatively affect sustainability of ecosystem restorations in future (drier and warmer) climate. Planted H. ammodendron established and thrived in the first 25 years, but the percent vegetation cover started to decrease afterwards because of reduction in deep soil moisture and less access to groundwater. By comparison, herbaceous plants gradually developed after H. ammodendron plantations and finally dominated the ecosystems with high density (300–400 herbs·m−1), cover (25–30%), and biomass (50–60 × 10−3 kg·m−2) after 30–40 years. These results suggest that although introduced shrubs can act as nurse plants to improve vegetation and soil conditions, their dominance could be a transient state. Thus, evaluation of ecosystem restoration through plantations should use long‐term data, and the stable plant restorations for years or even decades could be a transient state and does not necessarily suggest a successful revegetation effort in the long run. Further, its environmental consequences (i.e., soil salinity) of shrub plantations need to be evaluated in ecosystem restorations especially in a changing and harsh environment.

Gross primary productivity of a large metropolitan region in midsummer using high spatial resolution satellite imagery

Although gross primary productivity (GPP) is estimated with remote sensing over large regions of Earth, urban areas are usually excluded due to the lack of light use efficiency (LUE) parameters for urban vegetation and the spatial heterogeneity of urban land cover. Here, we estimated midsummer GPP, both within and among vegetation and land-use types, across the Minneapolis-Saint Paul, Minnesota metropolitan region. We derived LUE parameters for urban vegetation types using estimates of GPP from tree sap flow and eddy covariance CO2 flux observations, and from fraction of absorbed photosynthetically active radiation based on 2 m resolution WorldView-2 satellite imagery. Mean GPP per unit land area (including vegetation, impervious surfaces, and soil) was 2.64 g C m−2 d−1, and was 4.45 g C m−2 d−1 per unit vegetated area. Mapped GPP estimates were within 11.4% of estimates from independent tall tower eddy covariance measurements. Turf grass GPP had a larger coefficient of variation (0.18) than other vegetation classes (~0.10). Vegetation composition was largely consistent across the study area. Excluding golf courses, mean land-use GPP for the total study area varied more by percent vegetation cover (R2 = 0.98, p < 0.001) than by variability within vegetation classes (R2 = 0.21, p = 0.19). Urban GPP in general was less than half that of natural forests and grasslands in the same climate zone.

Remote sensing of Arctic percent vegetation cover and fAPAR on Baffin Island, Nunavut, Canada

Percent vegetation cover (PVC) and the fraction of absorbed photosynthetically active radiation (fAPAR) are important functional variables for assessing Arctic vegetation density and vigor. In this study, field measures of PVC, fAPAR and normalized difference vegetation index (NDVI) were collected from July 5 to August 8, 2015 (i.e., summer season) along a moisture gradient in the Apex River Watershed (ARW) (63°45′N, 68°30′W), Baffin Island, Nunavut, Canada. Two field methods for estimating PVC (i.e., the point-frame and image classification methods) were examined and it was determined that the image classification approach provided a suitable alternative to the point-frame method, especially for detecting changes in Arctic PVC. Meanwhile, fAPAR was measured based on the method presented by Tagesson et al. (2012): fAPAR=(1−PARReflectedPARIncoming)×PVC. The spatial and temporal patterns of PVC and fAPAR in the context of NDVI derived from remote sensing data were examined. For this site, vegetation types exhibited contrasting patterns of PVC as a result of differing moisture regimes: (1) vegetation types with saturated soils (e.g., sedge dominated) exhibited a continuous increase in PVC throughout the growing season; (2) mesic vegetation types with moderate soil moisture (e.g., mosses dominated with a mixture of sedges and shrubs) exhibited an increase in PVC from July to early August followed by a decline in mid-August; and (3) semi-desert vegetation types that tended to dry early in the growing season (e.g., dominated by prostrate dwarf shrubs, herb tundra and large areas of bare soil and rock) exhibited little variation in PVC. Field measures of PVC and fAPAR demonstrated strong relationships to field NDVI data and the vegetation indices (VIs) derived from 2 m-resolution WorldView-2 data, thereby providing further evidence that VIs are well-suited for modelling PVC and fAPAR of Arctic vegetation.

Assessing Near Surface Hydrologic Processes and Plant Response over a 1600 m Mountain Valley Gradient in the Great Basin, NV, U.S.A.

This study investigated near surface hydrologic processes and plant response over a 1600 m mountain-valley gradient located in the Great Basin of North America (Nevada, U.S.A.) as part of a long-term climate assessment study. The goal was to assess shifts in precipitation, soil water status and associated drainage with elevation and how this influenced evapotranspiration and plant cover/health estimated by a satellite-derived Normalized Difference Vegetation Index (NDVI), all to better understand how water is partitioned in a mountain valley system. Data were acquired during a three-year period from meteorological stations located in five plant communities ranging in elevation from 1756 m (salt desert shrubland zone) to 3355 m (subalpine zone). The analysis also included groundwater depths measured at the Salt Desert Shrub West site, mine water flow near the Pinyon-Juniper West site and drainage estimates using drainage flux meters at the four higher elevation sites. Annual precipitation increased with elevation in a linear fashion (R2 = 0.93, p &lt; 0.001) with an average increase of 2.9 cm for every 100 m in elevation. Reference evapotranspiration (ETref) declined in a highly linear fashion with elevation (R2 = 0.95, p &lt; 0.001) with an average 4.0 cm decline for every 100 m rise in elevation. Drainage occurred only at the Montane West and Subalpine West sites and not at the lower elevations. No drainage occurred after Julian day 160. Growing degree days were found to be negatively associated with the time of peak drainage (R2 = 0.97, p &lt; 0.001), the date drainage first occurred (R2 = 0.90, p &lt; 0.001), drainage duration (R2 = 0.79, p &lt; 0.001) and total drainage volume (R2 = 0.59, p &lt; 0.001). It was estimated that 27% of precipitation at the Montane West site (years 1, 2 and 3) and 66 % at the Subalpine West site (40% without year 1) contributed to drainage at the local site level, indicating possible strong recharge contribution from the higher elevation plant communities. Percent vegetation cover and ETref accounted for 94% of the variation in NDVI and 90% of the variation in ET totals when data from all sites were combined. Such data will be extremely valuable to collect and compare over time to assess shifts associated with potential climate warming and/or basin water diversion.

Comunidades de arañas ribereñas como indicadores de la condición de los ecosistemas fluviales en la cuenca del Río Piedras de Puerto Rico.

Human degradation of stream ecosystems has led to the creation of a number of methods to assess the severity of such anthropogenic impacts. Biomonitoring protocols that utilize aquatic organisms, in particular macroinvertebrates, are used worldwide as a way to evaluate stream ecosystems. Despite the various benefits these methods provide, they only take into account the stream channel, ignoring altogether the condition of the riparian zone. Other methods look at physical characteristics of both the riparian area and the stream, but ignore biota. Riparian consumers such as spiders have been proposed as potential bioindicators because they could provide a more holistic alternative for assessing stream impairment. Our aim was to determine whether changes in riparian spider communities could be used as indicators to separate sites with different levels of impact along an urban gradient. We conducted correlation analyses of riparian spider community metrics (abundance and species richness) and the percent of vegetation cover in subwatersheds with varying levels of urbanization, along with three other popular stream monitoring protocols. We found a clear difference in spider community composition among subwatersheds, with an overall trend for lower richness and abundances in more impacted sites. Spider abundance correlated significantly with percent vegetation coverage and spider family richness correlated significantly with two widely employed stream monitoring protocols. These findings support the utility of riparian spider communities as indicators for disturbances of stream ecosystems in Puerto Rico and should be incorporated into future biomonitoring protocols to ensure a more holistic view of the condition of stream ecosystems.

Influence of a large urban park on the local urban thermal environment

Green areas in the city can greatly improve the outdoor thermal environment, as well as mitigate the urban heat island effect by reducing summer air temperature. In a context of climate change, with the expected increase in temperature and intensity of heat waves, cooling by green areas is set to become increasingly important. In this study, field observations were carried out to investigate the thermal performance of a large urban vegetated park and its influence on thermal environment of the surrounding urban areas in Beijing, China. Measurements were conducted along a selected path during three summer days with clear skies and light winds by mobile traverses. The results showed that the park was cooler than the surrounding urban areas both during the daytime and at night. The mean air temperature differences between the park and the surrounding areas were in the range of 0.6–2.8°C at different times, with a maximum of 4.8°C observed at midnight. The results also found that as the distance from the park border increased, the ambient air temperature exhibited a gradually increasing trend. This indicated the park has a cooling effect on the urban environments adjacent to the park, and this cooling effect extended approximately 1.4km from the park boundary. The air temperature variations also depended strongly on the land cover characterizing the immediate environment of the measurement sites. Increasing the percent vegetation cover could significantly decrease air temperature, while the increase of percent impervious surface area would significantly increase it.

Investigation of pore water residence times and drainage velocities in salt marshes using short-lived radium isotopes

Abstract Pore water residence times and drainage velocities were investigated in Jamaica Bay (NY, USA), a highly urbanized estuary in New York City where salt marsh degradation and loss has accelerated in recent years. Five different marshes were sampled for shallow (25 cm) and deep (≥ 50 cm) dissolved 224 Ra over a several year period. Pore water residence times were estimated using a one-dimensional advective transport model, assuming that the pore water 224 Ra grows into an equilibrium 224 Ra activity, and that flow is vertical. Equilibrium between dissolved 224 Ra and the marsh sediment was assessed with respect to solid-phase 228 Th, 228 Ra, reactive solid-phase Fe and Mn, all of which except Mn scaled as a function of grain size. Pore water 224 Ra and estimated residence times did not display any seasonality between the marshes. The shortest residence times were estimated for the highest elevation, fine-grained-sand marsh (1.4 ± 0.9 d at 25 cm), which has the highest percent vegetation cover. We hypothesize that the faster drainage velocity (25.9 ± 17.8 cm d − 1 at 25 cm) of this marsh, combined with a higher mean elevation above sea-level, together limit exposure of the marsh plants to the build-up of H 2 S, a phytotoxin, in the pore fluid from the spring through summer. In contrast, shallow pore water residence times were greater for marshes with a lower elevation above sea-level, from (3.9 ± 1.8) d to (9.2 ± 3.6) d, where sediments were finer-grained, and throughput fluxes of Fe and H 2 S were higher throughout spring and summer seasons. This work demonstrates the utility of 224 Ra as a tracer of salt marsh flow dynamics, and highlights the importance of sediment heterogeneity and marsh platform elevation on the dynamic geochemistry of salt marshes.

Maintenance of agricultural drains alters physical habitat, but not macroinvertebrate assemblages exploited by fishes

The effects of drain maintenance on fish habitat and benthic macroinvertebrate assemblages (fish prey) were investigated for eight agricultural drains in southwestern Ontario, Canada. Our investigation employed a replicated Before-After-Control-Impact (BACI) design where each maintained section of a drain was paired with an unmaintained section downstream and an unmaintained section on a nearby reference drain of similar size and position in the watershed. Seven variables characterizing physical habitat features important to fishes and three variables characterizing the taxonomic abundance, densities, and relative densities of benthic macroinvertebrates were measured before drain maintenance and 10–12 times over 2 years following maintenance. Pulse responses were detected for three habitat variables quantifying vegetative cover: percent vegetation on the bank, percent in-stream vegetation, and percent cover. All three variables returned to pre-maintenance levels within two years of maintenance. No consistent changes were observed in the remaining habitat features or in the richness and densities of benthic invertebrate assemblages following drain maintenance. Our findings suggest that key features of fish habitat, structural properties and food availability, are resistant to drain maintenance.

Airborne LiDAR and Aerial Imagery to Assess Potential Burrow Locations for the Desert Tortoise (Gopherus agassizii)

The Southwestern United States desert serves as the host for several threatened and endangered species, one of which is the desert tortoise (Gopherus agassizii). The goal of this study was to develop a fine-scale, remote-sensing-based approach that indicates favorable burrow locations for G. agassizii in the Boulder City (Nevada) Conservation Easement area (35,500 ha). This was done by analyzing airborne LiDAR data (5–7 points/m2) and color imagery (four bands, 0.15-m resolution) and determining the percent vegetation cover; shrub height and area; Normalized Difference Vegetation Index (NDVI); and several geomorphic characteristics including slope, azimuth, and roughness. Other field data used herein include estimates of canopy area and species richness using 1271 line transects, and shrub height and canopy area using plant-specific measurements of ~200 plants. Larrea tridentata and Ambrosia dumosa shrubs were identified using an algorithm that obtained an optimum combination of NDVI and average reflectance of the four bands (IR, R, G, and B) from pixels in each image. The results, which identified more than 65 million shrubs across the study area, indicate that percent vegetation cover from aerial imagery across the site (13.92%) compared favorably (14.52%) to the estimate obtained from line transects, though the LiDAR method yielded shrub heights approximately 60% those of measured shrub heights. Landscape and plant properties were combined with known locations of tortoise burrows, as visually observed in 2014. Masks were created using roughness coefficient, slope percent, azimuth of burrow openings, elevation, and percent vegetation cover to isolate areas more likely to host burrows. Combined, the masks isolated 55% of the total survey area, which will help target future field surveys. Overall, the approach provides areas where tortoise burrows are more likely to be found, though additional ecological data would help refine the overall method.

Examining spectral reflectance features related to Arctic percent vegetation cover: Implications for hyperspectral remote sensing of Arctic tundra

In this study, we investigated the utility of hyperspectral remote sensing data for estimating green percent vegetation cover (PVC) for a study site in the Canadian High Arctic. A field experiment was conducted on Sabine Peninsula (76°27′ N, 108°33′ W), Melville Island, Nunavut, Canada to collect field spectra and PVC for five vegetation types, i.e., polar semi-desert (PD), dry mesic tundra (DMT), mesic tundra (MT), wet mesic tundra (WMT) and wet sedge/moss (WSM). Based on field spectra, two types of 2-band hyperspectral (i.e., Hyperion) and multispectral (i.e., WorldView-3) vegetation indices (VIs) were derived using all possible band combinations. Optimal spectral bands were identified based on their correlations with green PVC. In addition, VIs designed for other landscapes were examined for their ability to estimate green PVC in an Arctic environment. The results indicate that PVC and spectral features for Arctic vegetation types were related to moisture content: (1) vegetation types with dry to intermediate soil moisture (e.g., PD, DMT and MT) possessed large amounts of bare soil and exhibited spectral properties similar to bare soil; and (2) vegetation types with high moisture content (e.g., WMT and WSM) exhibited spectra similar to senescent vegetation given the substantial proportion of senescent vegetation in these vegetation types. The optimal Hyperion spectral bands for estimating green PVC were located at the absorption features observed in Arctic vegetation spectra, including 681.20nm (leaf pigment absorption); 721.90nm and 732.07nm (along the red-edge slope); 1174.77nm and 1184.87nm (leaf water absorption); and 1447.14nm, 1457.23nm, 2072.65nm and 2102.94nm (leaf cellulose and lignin absorption). Narrowband VIs exhibited a stronger correlation with green PVC than broadband VIs due to the finer spectral features sampled by hyperspectral data. Further, VIs designed to estimate leaf pigment and dry matter content (e.g., lignin and cellulose) showed strong correlations with green PVC.

Does Dust from Arctic Mines Affect Caribou Forage?

This study explores how dust from the Ekati Diamond Mine potentially affects the availability and quality of forage on the seasonal range of the Bathurst caribou herd. Understanding the effects of dust as a source of disturbance is important because the Bathurst caribou population has declined by 93% since the middle 1980s and there are reports that caribou in general may avoid mining projects. There are several challenges for quantifying dust impacts: 1) Natural variations (e.g., topography, natural disturbance, and soil pH) may also impact forage availability and quality for caribou. To minimize their masking effect, we stratified survey sites into seven land cover classes and selected the most populous class (i.e., the dwarf shrub) for assessing the impact. 2) Within class variation (e.g., the proportion of area covered by rocks where vascular plants and lichen do not grow) can further skew the analysis. We eliminated this problem by examining only the area not covered by rocks. 3) Coarse and fine suspended particulates have different spatial coverages, chemical compositions, and pH values. Consequently, their impacts on caribou forage can be different. To distinguish their impacts, we sampled two areas: transects from the Misery Haul Road that has been in active use vs. those from a rarely used spur road outside the Misery Camp. We sampled percent vegetation cover, soil pH, and dust on leaves along these transects during the summers of 2015 and 2016. Our results indicated that the amount of dust on leaves in a zone of ~1000 m from the Misery Haul Road was 3 - 9 times than that of background sites. The zone of reduced lichen percent cover was also about 1000 m. In contrast, these road dust-induced changes in caribou forage were not observed for the dust-free transect from the spur road.

Assessing the performance of remotely sensed landscape function indices in semi-arid rangelands of Iran

Appropriate rangeland management requires rangeland function analysis at broad scales. This study aimed to examine the potential of remotely sensed function indices extracted from Landsat data to evaluate the function of semi-arid rangelands in central Iran at the sub-basin scale. Three replicate 30-m transects were randomly placed in the dominant slope direction of 14 selected sub-basins. Various structural properties of vegetation (e.g. number and size of vegetation patches and interpatch lengths) and soil surface were scored based on the landscape function analysis (LFA) procedure. The obtained structural and function indices of the LFA, as well as field percent vegetation cover, were compared with the perpendicular distance vegetation index and remotely sensed function indices including proximity, lacunarity, leakiness index, and weighted mean patch size (WMPS). Remotely sensed function indices were found to be capable of discriminating rangeland landscapes with different conditions. Results showed that the structural properties of vegetation considered in the LFA could also be obtained through WMPS and proximity indices (R &gt;0.76; P &lt; 0.01). All indices, except for lacunarity, had significant correlations with percent vegetation cover and the strongest correlation was observed between WMPS and proximity. Our findings highlight the usefulness and efficiency of function indices derived from satellite data in the estimation of structural and functional properties of rangeland landscapes at the sub-basin scale.

Modelling high arctic percent vegetation cover using field digital images and high resolution satellite data

In this study, digital images collected at a study site in the Canadian High Arctic were processed and classified to examine the spatial-temporal patterns of percent vegetation cover (PVC). To obtain the PVC of different plant functional groups (i.e., forbs, graminoids/sedges and mosses), field near infrared-green-blue (NGB) digital images were classified using an object-based image analysis (OBIA) approach. The PVC analyses comparing different vegetation types confirmed: (i) the polar semi-desert exhibited the lowest PVC with a large proportion of bare soil/rock cover; (ii) the mesic tundra cover consisted of approximately 60% mosses; and (iii) the wet sedge consisted almost exclusively of graminoids and sedges. As expected, the PVC and green normalized difference vegetation index (GNDVI; (RNIR−RGreen)/(RNIR+RGreen)), derived from field NGB digital images, increased during the summer growing season for each vegetation type: i.e., ∼5% (0.01) for polar semi-desert; ∼10% (0.04) for mesic tundra; and ∼12% (0.03) for wet sedge respectively. PVC derived from field images was found to be strongly correlated with WorldView-2 derived normalized difference spectral indices (NDSI; (Rx−Ry)/(Rx+Ry)), where Rx is the reflectance of the red edge (724.1nm) or near infrared (832.9nm and 949.3nm) bands; Ry is the reflectance of the yellow (607.7nm) or red (658.8nm) bands with R2’s ranging from 0.74 to 0.81. NDSIs that incorporated the yellow band (607.7nm) performed slightly better than the NDSIs without, indicating that this band may be more useful for investigating Arctic vegetation that often includes large proportions of senescent vegetation throughout the growing season.

Effects of plant roots on the soil erosion rate under simulated rainfall with high kinetic energy

ABSTRACTThis study examined the effects of herbaceous plant roots on interrill erosion using two herbaceous species: clover (Trifolium repens) and oats (Avena sativa). We developed a simple rainfall simulator with relatively high normalized kinetic energy (KE; 23.2 J m−2 mm−1). Under simulated rainfall, we measured eroded soil for 42 boxes with various amounts of aboveground and belowground biomass. Aboveground vegetation had a significant effect on the soil erosion rate (SER). We found a clear negative relationship between the percent vegetation cover (c) and the SER. In contrast, plant roots showed no effects on the SER. The SER was not significantly different between the boxes with and without plant roots under similar c conditions. Thus, plant roots could have less of an effect on the SER under higher KE conditions.Editor M.C. Acreman Associate editor N. Verhoest

Biogeomorphic disturbance: A case study on associations and methods after fire within the alpine treeline ecotone

Biogeomorphology is an increasingly popular field of study, but the approaches to biogeomorphic research and methods are not yet well developed. This research evaluated ecologic and geomorphic interactions after fire within the alpine treeline ecotone of Glacier National Park, Montana. Associations between soil conditions and vegetation, the effect of vegetation edges on soil characteristics, and the influence of quadrat size on select vegetation and soil variables were evaluated with the use of fieldwork and statistics. Of the 11 ecologic/soil variables compared, three were significantly correlated – soil compaction and krummholz density, soil loss and percent vegetation, and soil loss and burn severity. The ecologic edge between burned and unburned krummholz had significant influence on soil compaction, clast size, and effective soil depth patterns. Quadrat size did not have much influence on average results for either soil or vegetation variables. These findings highlight both the potential biogeomorphic interactions as well as interesting results that were not significant, and will contribute to the advancement of biogeomorphology. The results also provide novel information on alpine treeline ecotone response after fire.

Fish Assemblage Associations with Floodplain Connectivity Following Restoration to Benefit an Endangered Catostomid

AbstractThe dynamics of stream and floodplain connectivity are a growing consideration for restoration projects. Restoration of a tributary stream to Utah Lake was undertaken in 2008 with the intent of increasing available spawning and nursery habitat for the endangered June Sucker Chasmistes liorus. Restoration efforts provided an opportunity to evaluate relationships between fish assemblages and variables related to the physiochemical environment, vegetation, and habitat connectivity at floodplain ponds. Fish were collected with beach seines and habitat variables were measured each month at 12 floodplain ponds during March 2010 to March 2011. Total catch was predominated by nonnative species: Green Sunfish Lepomis cyanellus, Western Mosquitofish Gambusia affinis, Black Bullhead Ameiurus melas, Fathead Minnow Pimephales promelas, and Bluegill Lepomis macrochirus. Both indirect and direct gradient analyses indicated a significant correlation between fish assemblages and site connectivity. The percentage and type of macrophyte cover (e.g., emergent, submergent) also played a significant role in structuring fish assemblages. Species richness was generally higher at sites with intermediate to high connectivity than at sites with lower connectivity. Sites with lower connectivity were predominated by Green Sunfish, Mosquitofish, and Fathead Minnow. June Suckers were collected from sites with intermediate values of connectivity and vegetation. Observed patterns suggested connectivity structured initial fish assemblages and macrophyte colonization dynamics; subsequent interactions between local habitat (i.e., percent vegetation) and biotic factors (e.g., competition, predation, etc.) provided site‐specific interactions and structure. The results of this study indicate connectivity dynamics should be an important consideration in stream and floodplain restoration efforts.

Water Delivery Performance Evaluation of a Tank Irrigated System and Best Management Practices for Paddy Agriculture

Objectives: To identify the current agricultural practices, challenges faced in paddy agriculture and analyse the water delivery performance of tank using RS and GIS. To review and compare the current agriculture practices with the BIS and other standards and to propose BMP’s for paddy cultivation. Methods/Analysis: Random sampling of survey was taken and frequency analysis was done by questionnaire. The performance of irrigation system was carried out by rainfall frequency analysis by using Weibull’s formula. The water delivery performance was obtained by NDVI analysis. The current practices of paddy agriculture is analysed and compared with BIS 15930 (Part 1): 2010, TNAU and FAO reports to provide BMPs for improving the productivity. Findings: The NDVI values classified as high, low and normal water delivery performance for years of 2002, 2006, 2009 and 2011. The percentage of area under high vegetation of paddy in the year 2002 was 28% and increased to 31% in the year 2011, because of the rainfall in 2002 was 1032 mm, whereas it was 1499.6 mm in 2011. The drought year 2009, is characterized by a very drastic change of 0% percent vegetation in the tail end region of Navarai season. But, in the Samba season, the vegetations decreased as much as 9.8% when compared to vegetation in the Samba season of 2002. It can be inferred from the NDVI map of the Samba season of 2009, there is an increase in the high paddy vegetation in the tail end. The reason is an increase in the number of bore wells dug for paddy cultivation because of poor water delivery performance. Best management practices have been recommended, for the paddy cultivation. Conclusion: The farmers faced problems in water sharing, fragmentation; non-maintenance of supply system, non-availability of labours; consequently people involvement in agriculture is decreasing. By enhancing the water delivery performance and adopting best management practices, the productivity and farmers livelihood will increase.