Percentage Of Vegetation Research Articles

The context dependency of fish-habitat associations in separated karst ecoregions.

Fish populations may be isolated via natural conditions in geographically separated ecoregions. Although reconnecting these populations is not a management goal, we need to understand how these populations persist across landscapes to develop meaningful conservation actions, particularly for species occupying sensitive karst ecosystems. Our study objective was to determine the physicochemical factors related to the occurrence of four spring-associated fishes. Arbuckle Uplift and Ozark Highlands ecoregions, USA. We used a hierarchical approach to identify habitat relationships at multiple spatial scales. We collected detection data using snorkeling and seining. We examined the physicochemical relationships related to the detection and occurrence of four spring-associated fishes using occupancy modeling in a Bayesian framework. We found physicochemical relationships that differed and were similar between ecoregions for several fishes. For three species, we found different water temperature relationships between ecoregions. Smallmouth bass were ubiquitous in their use of drainage areas in the Ozark Highlands but only associated with the lower network of the Arbuckle Uplift. There were several mirrored relationships between ecoregions, including an interaction between residual pool depth and water temperature, where sites with deeper pools were more likely to be occupied during warmer water temperatures. There were single-species occurrence relationships with percent vegetation and percent agriculture. Lastly, snorkeling was a more efficient sampling method compared to seining for all fishes. Our results indicate stream temperature mitigation may be possible via the maintenance of key channel morphologies, and we identify shared stressors between ecoregions. Channel mitigation to maintain reaches with deeper pools may be an important strategy for maintaining thermal refugia, particularly when considering climate change. Identifying the mechanistic underpinning of other multiscale ecological relationships would be helpful to discern if some of the different ecoregion relationships represent warning signals or interactions with unmeasured biotic or abiotic factors.

Mapping landscape ecological patterns using numeric and categorical maps.

The reciprocal relationships between ecological process and landscape pattern are fundamental to landscape ecology. Landscape ecologists traditionally use raster maps portraying classified features such as land use or land cover categories, and metrics suggested by the patch-corridor-matrix conceptual model of pattern. Less attention has been given to the landscape gradient conceptual model and raster maps portraying numeric features such as greenness or percent vegetation cover. We introduce the open-source tool GraySpatCon to calculate and map a variety of landscape pattern metrics from both conceptual models using either categorical or numeric maps. The 51 metrics, drawn mostly from the landscape ecology and image processing literatures, are calculated from the frequencies of input pixel values and/or the pixel value adjacencies in an analysis region. GraySpatCon conducts either a moving window analysis which produces a continuous map of a pattern metric, or a global analysis which produces a single metric value. We describe an implementation in the GuidosToolbox desktop application which allows novice users to interactively explore GraySpatCon functionality. In the R desktop environment, we demonstrate several metrics using an example map of percent tree cover and illustrate a multi-scale moving window analysis to identify scale domains. Comparisons of computational efficiency indicate a substantial GraySpatCon advantage over related software in the R environment.

Responses of Urban Bird Assemblages to Land-Sparing and Land-Sharing Development Styles in Two Argentinian Cities

Urbanization negatively affects biodiversity worldwide. Consequently, alternative urban development styles are required for an eco-friendlier urbanization process. Thus, two development styles have been suggested: land-sharing (buildings mixed with dispersed green space) and land-sparing (buildings interspersed with large green patches). We assessed differences in species diversity and composition of bird assemblages between both development styles in two Argentinian cities: Santa Fe and Buenos Aires. We surveyed birds in land-sharing and land-sparing areas during the breeding and non-breeding seasons. As a control, we also surveyed birds in areas dominated by impervious surfaces. At a local scale, we also measured the environmental noise and pedestrian traffic. At a landscape scale, we measured the percent vegetation cover surrounding development styles and their distance to the main river. In Buenos Aires, species richness was higher in land-sparing than in land-sharing. However, the Shannon diversity and Simpson diversity were higher in land-sharing. In Santa Fe, both urban development styles supported similar species richness and diversity. Species composition varied between land-sharing and land-sparing in both cities during the breeding season. The pedestrian traffic was negatively associated with species diversity. Therefore, both development styles and strategies to reduce pedestrian traffic should be taken into account to enhance different components of species diversity and composition within the urban matrix.

Plant growth promoting microorganisms (PGPM) as an eco-friendly option to mitigate water deficit in soybean (Glycine max L.): Growth, physio-biochemical properties and oil content

Drought, as an important challenge in Iran, affects all growth indicators for plants. Application of plant growth promoting microorganisms (PGPM) can reduce the detrimental effects of water deficit on plants. Two separate field experiments were conducted at the Tehran and Hashtrood sites, Iran in 2019 to study the influences of Azotobacter chroococcum (Az) and Piriformospora indica (Pi) or Az + Pi on growth, physio-biochemical properties and oil content of soybean (Glycine max L.) under water deficit conditions. Although water deficit dramatically reduced the plant height, percent vegetation cover and relative water content (RWC), plots treated with Az and Pi exhibited higher performance mentioned traits at both sites. Besides, co-inoculation of Az and Pi increased proline in Tehran (48.85 and 29.24% in leaf and root, respectively) and Hashtrood (46.91 and 48.91% in leaf and root, respectively) under severe water deficit. Accumulation of glycine betaine, soluble sugars and proteins increased for plots which received Az and Pi. Under severe water deficit conditions, the co-inoculation with Az and Pi enhanced the oil content of soybean by 12.87 and 9.37% at Tehran and Hashtrood sites respectively. Application of Az and Pi resulted in reducing the adverse effects of water deficit on oil quality of soybean by increasing the linoleic and linolenic acid in oil. Moreover, inoculation of soybean with Az and Pi can provide drought tolerance by improving ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD) and peroxidase (POX) activity. However, co-inoculation with Az and Pi was generally more effective in the alleviation of water deficit detrimental effects than sole inoculation with Az and Pi. Consequently, it can be a good approach for improving tolerance, growth and oil production of soybean under water deficit conditions.

What are the factors influencing recreational visits to national forest parks in China? Experiments using crowdsourced geospatial data

Quantifying recreational visits to national forest parks (NFPs) and deciphering associating driving factors is significant for NFP protection, management, development, and planning; however, previous studies have primarily conducted questionnaire-based surveys or semi-structured individual interviews to gather limited data, while few have employed big data to effectively and efficiently estimate NFP visits and further explored correlated factors. This study used location-based service data from social media to quantify recreational NFP visits, and search for any associations with spatio-physical park factors selected based on previous constructive studies and NFP visitor perceptions of travel experiences posted on social media. A spatial error model with maximum likelihood estimation (SEM-MLE) was applied to investigate the significance. Sixty-eight (68) NFPs located in the Yangtze River Delta urban agglomeration (YRDUA) were selected as experimental cases. The results indicated that: (i) The number of NFP check-in visits was unevenly distributed across the YRDUA; (ii) NFP size and biodiversity (i.e., the number of vegetation and animal species) were not correlated with check-ins; (iii) Three NFP attributes (entrance fee, percent vegetation cover, and the presence of recreational water activities), one accessibility variable (potential visitors to NFP), and one transport variable (driving time to train station), had a significant influence on NFP check-ins, collectively explaining 49.69% of the observed variation. These findings can help NFP managers and planners understand the internal and external factors influencing recreational visits, thus more strategically informing nature-based tourism design and promotion campaigns.

UAV-based prediction of ryegrass dry matter yield

ABSTRACT Forage yield is traditionally measured by manual harvesting, drying, and weighing and has multiple uses, including plant breeding and pasture management. The goal of this paper was to determine the accuracy of unmanned aerial vehicle (UAV)-based prediction of ryegrass percentage cover, vegetation volume, and dry matter (DM) yield in Autumn from 300 rectangular 1.5 m2 plots at a height of 20 m above ground level, compared to the current manual method. The secondary goal was to evaluate the UAV-based method for the determination of dry matter yield from five different ryegrass cultivars. A photogrammetry-based technique combined with a spectral method to determine the soil level was used to determine the percentage cover and vegetation volume of ryegrass plots, which were then used to obtain calibration curves to predict DM yield per plot. Calibration curves were obtained for five different ryegrass cultivars, with concordance between calibration curves for four of the five cultivar populations. The relationship between predicted forage volume (m3) and measured DM (g per 1.5 m2 plot) for ryegrass Populations 1,2,4,5 had an R2 = 0.61. Population 3 was different to Populations 1,2,4,5, with a two-fold difference in DM yield for the same forage volume. This demonstrated that 61% of the variance in DM yield can be explained by forage volume determined by a UAV-based photogrammetry method. We also further tested the methodology from 70 rectangular 2.4 m2 ryegrass plots in a Spring trial. The relationship between the predicted DM yield per 2.4 m2 plot (based on the average predictions from forage volume and forage area models) and measured DM yield per plot had an R2 = 0.66. UAVs can therefore increase the acquisition of field data for research studies and the management of pasture in grazed farm systems.

Evaluation of created wetlands as amphibian habitat on a reforested surface mine

Wetlands created within disturbed landscapes may be an important key to restoring lost ecosystem functions. Reclaimed mines provide an opportunity to create wetlands and restore natural features within a disturbed landscape while benefiting amphibians, a taxa affected by habitat loss. A large-scale restoration effort within the Monongahela National Forest, West Virginia, USA has resulted in the creation of over 1400 small wetlands. We sampled 39 of these wetlands among four ages (2, 4, 6, and 8 years) to: 1) characterize differences in wetland habitat, 2) estimate amphibian occupancy and abundance, 3) identify wetland characteristics most important for amphibian utilization of wetlands. Mean wetland size, percent canopy cover, percent vegetation cover, distance to the nearest stream, and distance to the nearest forest varied significantly among wetland age classes. Water quality was within normal parameters for natural and created wetlands within our study region. Amphibian occupancy and abundance varied by species, with occupancy predicted by wetland age (Green Frog, Lithobates clamitans) and lower percent vegetation cover (Spotted Salamander, Ambystoma maculatum, L. clamitans) while abundance was predicted by wetland age (A. maculatum), higher percent vegetation cover (Eastern Newt, Notophthalmus viridescens), larger wetland surface area (A. maculatum, N. viridescens), and shorter distance to forest (N. viridescens). Our results indicate, with adequate site preparation, created wetlands on reforested surface mines provide suitable breeding habitat for pond breeding amphibians.

Effect of initial planting on vegetation establishment in different depth zones of constructed farm ponds

Farm ponds can be constructed and maintained to improve biodiversity and ecosystem functions in agricultural landscapes. Understanding the initial establishment process of vegetation in different water depths and effects of initial planting on this process is important for pond restoration. In the present study, two experimental farm ponds with or without initial planting were monitored for 5 years after their construction. These two ponds maintained high nutrients over 5 years from the beginning. The unplanted pond showed a rapid vegetation establishment and had more species and higher percent vegetation cover in 2–3 years than the reference pond. Planting accelerated this process by 1 year. Most of the early established species appeared to have originated from seed banks and/or seed rains. The species and functional diversity tended to decrease consistently since pond construction in the planted pond but increase initially and then decrease in the unplanted pond. The time when species composition between the unplanted pond and the planted pond became similar was delayed with the increase of water depth. Four years after pond construction, species composition was similar between the two ponds at all water depths. These results suggest that vegetation can establish quickly in farm ponds with fertile conditions and abundant seed sources through natural recolonization. The restoration approach for a farm pond should be decided considering the allowed time to success and the water depth. If the main goal of farm pond restoration is to improve species diversity, management practices may be more important than planting.

Stream Temperature and Environment Relationships in a Semiarid Riparian Corridor

This study examined the relationship between stream temperature and environmental variables in a semiarid riparian corridor in northcentral Oregon, USA. The relationships between riparian vegetation cover, subsurface flow temperature, and stream temperature were characterized along an 800 m reach. Multiple stream temperature sensors were located along the reach, in open and closed canopy areas, with riparian vegetation cover ranging from 4% to 95%. A support vector regression (SVR) model was developed to assess the relationship between environmental characteristics and stream temperature at the larger valley scale. At the reach scale, results show that air temperature was highly correlated with stream temperature (Pearson’s r = 0.97), and no significant (p < 0.05) differences in stream temperature levels were found among sensor locations, irrespective of percent vegetation cover. Channel subsurface temperature levels from an intermittent flow tributary were generally cooler than those in the perennial stream in the summer and warmer during winter months, indicating that the tributary may have a localized moderating effect on stream temperature. At the valley scale, results from the SVR model showed that air temperature, followed by streamflow, was the strongest variable influencing stream temperature. Also, riparian area land cover showed little effect on stream temperature along the entire riparian corridor. This research indicates that air temperature, subsurface flow, and streamflow are important variables affecting the stream temperature variability observed in the study area.

Associations of objective and perceived greenness measures with cardiovascular risk factors in Philadelphia, PA: A spatial analysis

There is mounting scientific evidence that greenness is associated with improved cardiovascular health. However, few studies have distinguished between vegetation type, measured perceived green space access, or investigated heterogeneity of associations across categories of neighborhood sociodemographic and racial/ethnic composition. We conducted an ecologic spatial analysis of associations of three objective measures of greenness (percent vegetation cover, percent tree canopy cover, and greenness density), and one measure of perceived access to green spaces with census tract level percentages of the adult population who were obese, ever had a high blood pressure diagnosis, and ever had a diabetes diagnosis, in the city of Philadelphia, PA, year 2013. We explored effect modification by census-tract level percent living in poverty and percent non-Hispanic Black categories. We used data from the Southeastern Pennsylvania Household Health Survey (SEPAHH) linked with high-resolution landcover, remotely sensed, and American Community Survey data and estimated associations using spatial lag models. We observed modest protective associations between percent of the adult population reporting perceived access to green spaces and percent with the cardiovascular risk factors, particularly in moderate and high poverty census tracts. Percent tree canopy cover was also protective against the cardiovascular risk factors, particularly in census tracts with low percentages of the population living in poverty and with low percent non-Hispanic Black populations. These results suggest that perceived access to green spaces and objectively measured high tree canopy cover, may protect against cardiovascular disease, but associations may vary across neighborhood sociodemographic categories.

Macrophytes as indicators of the ecological status of a tropical rehabilitated wetland ecosystem: Application of multivariate statistics and Ecological State Macrophyte Index (ESMI)

The present study used the Ecological State Macrophyte Index (ESMI) and the multivariate statistical methods to assess the ecological status and the variation of macrophytes in a tropical wetland system. Six sites were selected from rehabilitated and non-rehabilitated areas of an urban tropical wetland and the water quality parameters (water pH, temperature, conductivity, total dissolved solids (TDS), dissolved oxygen (DO), visibility, biological oxygen demand 5 days after incubation (BOD 5 ), chemical oxygen demand (COD), nitrate, chlorophyll-a and total phosphorus concentrations), sediment quality parameters (pH, organic matter content, percentage sand, silt and clay content) and abundance of aquatic macrophytes were measured. Shannon Weiner diversity index, percentage vegetation under anthropo-pressure, macrophyte settlement rate and ESMI were calculated. Significant variations in the water and sediment quality parameters were observed and ten species of aquatic macrophytes were recorded. Salvinia melosta and Cypreus iria were recorded only from the non-rehabilitated sites. Although there was no significant difference in the percentage anthropo-pressure among study sites, the rehabilitated sites were displayed low anthropo-pressure. The sites in the non-rehabilitated area showed a significantly lower macrophyte settlement rate. ESMI and macrophyte abundance showed significant correlations with water quality parameters. Based on the results, it can be recommended that applications based on ESMI and multivariate statistics can be used to assess the ecological status of tropical wetlands.

A High Spatial Resolution Satellite Remote Sensing Time Series Analysis of Cape Bounty, Melville Island, Nunavut (2004–2018)

Changes in vegetation have been observed in areas of the Arctic due to changing climate. This study examines a normalized difference vegetation index (NDVI) time series (2004–2018) of high spatial resolution satellite data (i.e., IKONOS, WorldView-2, WorldView-3) to determine if vegetation abundance has changed over the Cape Bounty Arctic Watershed Observatory, Melville Island, Nunavut. Image data were corrected to top-of-atmosphere reflectance and normalized for time series analysis using the pseudo-invariant feature (PIF) method. Percent vegetation cover measurements and indices derived from local climate data (growing degree days base 5 °C; GDD5) were used to contextualize NDVI trends in different vegetation types and within active layer detachments (ALDs). NDVI showed similar patterns within the different vegetation types and across the ALDs. There was no significant change in NDVI nor in GDD5 over time. However, there were statistically significant (p < 0.05) relationships between the GDD5 and NDVI for all vegetation types. Using field measurements with high spatial resolution remote sensing data helps link changes in NDVI with changes to vegetation and earth surface processes. The challenges of integrating high spatial resolution satellite data from different sensors in a time series analysis are also discussed.

Investigation of land surface phenology detections in shrublands using multiple scale satellite data

Shrublands occupy about 13% of the global land surface, contain about one-third of the biodiversity, store about half of the global terrestrial carbon, and provide many ecosystem services to a large amount of world's human population and livestock. Because phenology is a sensitive indicator of the response of shrubland ecosystems to climate change, the alteration of ecosystems following species invasions, and the dynamics of shrubland ecosystem function, biodiversity, and carbon budgets, it is critical to monitor and assess phenological dynamics in shrubland ecosystems. However, most current land surface phenology (LSP) products derived from satellite data do not provide phenology detections in some semiarid shrublands where the amplitude of seasonal vegetation greenness is small. Therefore, we investigated the LSP detection using multiple spatial resolution satellite data and examined the impacts of spatial scales and shrubland ecosystem components (shrub and herb cover) on LSP detections over the western United States. Specifically, greenup onset date (GUD) in shrublands was detected from 30 m Harmonized Landsat and Sentinel-2 (HLS) data and 500 m Visible Infrared Imaging Radiometer Suite (VIIRS) data to quantify scale effects. The GUD spatial patterns were explored with 30 m pixel variations in shrubland ecosystem components. The results show that GUD values varied with percent vegetation cover and shifted to earlier dates with increasing vegetation cover, demonstrating that satellite observations were not able to capture greenup onset until a threshold of green vegetation cover is reached. GUD was mostly undetectable from both HLS and VIIRS pixels with vegetation cover less than 10% and became fully detectable with vegetation covers larger than 50%. Similarly, the differences of GUD between HLS and VIIRS detections also decreased with increased vegetation cover. As a result of high shrubland heterogeneity, GUD from 30 m HLS pixels could be partially detected within a 500 m pixel despite GUD being undetectable from VIIRS time series. Moreover, vegetation cover heterogeneity also made it difficult for GUD at 30 m to be aggregated to coarse scales (such as to 500 m VIIRS pixels). These findings have significant implications to the detection and characterization of shrubland LSP responses to environmental and climate changes.

Distribution, habitat suitability, conservation state and natural history of endangered salamander Bolitoglossa pandi.

BackgroundPandi’s mushroom-tongue salamander (Bolitoglossa pandi) is one of the threatened amphibians in South America, as well as a flagship species for the Colombian conservation agenda. This species is endemic to the Andean cloud forests of the western slope of the Cordillera Oriental of Colombia, occurring only in the department of Cundinamarca within a narrow elevational range. At night, B. pandi can be seen perching on the upper side of leaves at heights ranging from ground level to 2.5 m. During the day, it can be found under leaf litter or cover objects. Few studies have provided relevant information that can help the Colombian government to formulate lines of action for the conservation of this species; consequently, its threat assessments so far have been based on very limited information.MethodsWe conducted surveys for salamanders in four municipalities of Cundinamarca, Colombia, using two approaches: visual encounter surveys (Guaduas and Villeta) and the basic sampling protocol for single-species occupancy modeling (Supatá and Venecia). Multivariate analyses were employed to explore the correlation between habitat structure and natural history traits, abundance, and detection/non-detection of B. pandi. We evaluated the B. pandi activity pattern through kernel density curves for each sampling occasion and explored the variability of salamander abundance during their activity period by performing a nested ANOVA.ResultsWe report the discovery of two new populations of B. pandi, which represent the most northwestern records known. A significant correlation between body length, body mass, and habitat structure was observed. Multivariate analyses indicated that leaf litter depth, mean temperature, percent vegetation cover, and altitude were the habitat variables that together explained 60.3% of the B. pandi abundance variability, as well as the main determinants of its optimal habitat. Bolitoglossa pandi exhibits an activity pattern characterized by two main activity peaks, in which niche time-partitioning was observed. Across the surveyed area, we found a healthy, stable, highly dense population of B. pandi (>1,300 individuals), with seasonal variability between development stages.DiscussionGiven the high habitat specificity of B. pandi, the species is highly vulnerable to local changes. Thus, we recommend that B. pandi be retained as Endangered (EN) on the IUCN Red List, based on the IUCN Criterion B, given its restricted extent of occurrence (ca. 2,500 km2) and the ongoing threats from agriculture, cattle ranching, logging, and urban development, which continue to reduce its suitable habitat.

Reclassifying the Wildland–Urban Interface Using Fire Occurrences for the United States

The wildland–urban interface (WUI) occurs at the intersection of houses and undeveloped wildlands, where fire is a safety concern for communities, motivating investment in planning, protection, and risk mitigation. Because there is no operational definition of WUI based on where fires in fact have occurred, I used fire occurrences to objectively establish a definition of WUI, while examining spatiotemporal changes, for the conterminous United States. I applied four classifiers, but focused on C5.0, which produced equivalent sensitivity (0.87 to 0.91 at prevalence = 0.67) and generated a ruleset that indicated housing density was the preferable basis for definitions. Fire occurrences overall were predicted for housing densities &lt;100 houses/km2 with potentially low (≥10%) thresholds for percent vegetation cover, varying by housing densities and models. A generalized guideline according to classifications is continued use of existing definitions for wildlands of &lt;6.17 houses/km2 and a low-density intermix class of 6.17 to 50 houses/km2. Departing from other definitions, the medium-density class encompasses 50 to 100 houses/km2 and the high-density class is 100 to 200 houses/km2. Interface, or suburban, communities are 200 to 400 houses/km2. Implications of refining the definition include a larger critical area classified as greater fire risk (low and medium-density WUI below 100 houses/km2) at 855,000 km2 during 2010, and; therefore, incorporation of more communities and homeowners into a high-risk status. The low-density class had greatest risk of fire exposure, but the medium-density class contained a greater concentration of houses. Classification of the wildland–urban interface or intermix based on realized fire occurrences provides an objective foundation for identifying residential densities at risk of fire exposure, which permits disclosure of risk, prioritization of resources to communities and homeowners with greater wildfire exposure, development of strategies for communities to coexist with fire, and responses to reduce vulnerability.

An intelligent algorithm to recommend percent vegetation cover (ARVC) for PM2.5 reduction

Nowadays, increasing particulate matter (PM) remains a challenge for environmental and humanity health and increases death statistics. Case studies and experimental observations demonstrated that vegetation coverage and type of plants affect PM and air quality. Condensation of PM2.5 has an impressive effect on deteriorating air quality. Increasing vegetation coverage has a significant impact on reducing PM2.5. However, the requirement percent vegetation cover (PVC) is likewise a shadow for careful analysis to recommend the requirement percent and area of vegetation for different parts of the metropolitan. In this paper, we propose a four-phase intelligent algorithm for investigating PM2.5 and critical situations to detect unhealthy air quality monitoring stations (AQMSs). Our algorithm makes a decision based on fuzzy and neural network methods and recommends the percent density and area of vegetation. Our analysis of the weather condition is event-driven, considering rainfall as an event to examine the situation of each AQMS before and after rainfall. The experiments demonstrate reducing PM2.5 > 150 to PM2.5 < 50 using recommending PVC of approximately 20–74%. We achieved these results by periodically estimating and evaluating weather conditions in the autumn and winter as two critical seasons of the year.

Summer diet selection of a rock specialist: the Wolffsohn´s viscacha (Lagidium wolffsohni) in protected natural area of Pinturas River, Cueva de las Manos, Patagonia, Argentina

ABSTRACT Rock specialists are mainly herbivores with similar morphological and behavioral characteristics such as spatial activity and feeding near rocky outcrops. In mountain areas, they are vulnerable due to restrictions in food searching and many are also sensitive to warm temperatures. The Wolffsohn’s viscacha (Lagidium wolffsohni) is a high-altitude rock specialist whose conservation status IUCN is Data Deficient. This study investigates its feeding behavior in relation to food availability and evaluates the degree of trophic specialization in summer. Percent vegetation cover was estimated on three rocky outcrops inhabited by the Wolffsohn’s viscacha, and diet was estimated conducting a microhistological analysis of fecal pellets from 83 fresh fecal pellet groups. Wolffsohn’s viscacha was a selective consumer of grasses and its trophic niche was narrow (Bst = 0.31 ± 0.04). Its diet consisted of 17 food items. The grasses Festuca pallescens, Pappostipa spp., Poa spp., and shrub Berberis heterophyla composed 81% of the diet. The selective feeding behavior by grasses was similar to the southern vizcacha. Both herbivores selected a high-quality shrub and grasses in summer. This feeding behavior suggests a selection based on the availability of quality food near rocky outcrops representing a low cost of searching time and high contribution of nutrients.

Quantitative analysis of the interannual variation in the seasonal water cooling island (WCI) effect for urban areas

Water body, as water cool islands (WCIs), is an effective factor of mitigating the urban heat island (UHI) effects through the evaporation and absorption of solar shortwave radiance. In this study, a combination of the range, amplitude, efficiency and capacity of the WCI effect (WCI_R, WCI_A, WCI_E and WCI_C as descriptors) within water buffers, is proposed to evaluate the interannual variation of the seasonal WCI effects within the fifth loop of Beijing from 2000 to 2018, further construct optimal regression models by seven impact factors with the four WCI descriptors through all-subset regression, as well as calculate the independent contribution rate (CR) of these factors by hierarchical partitioning (HP) analysis. The results indicate that (1) In terms of the interannual variation of WCI effects, the most significant trends that rise over fall produced by four descriptors generate in summer after 2009, while relatively stable states exist in spring and winter. (2) As for the impact factors, the water temperature (WT) and the percentage of vegetation (PV) contribute most for WCI_R, WCI_A and WCI_E in reaction to the interannual average, while the water temperature capacity (WTC) maintains significant impact on WCI_C from spring to autumn over 18 years but shares power with water temperature (WA) and WT in winter. (3) Considering the factor changes yearly, the dominance relationships of external ones, mainly the percentage of impervious surface (PI) and PV, gradually surpass that of WA and WTC in four seasons especially after 2009. On this basis, urban designers could propose suitable plans to better exert the cooling effect of water bodies, thereby reducing the UHI effect.

Differences in vegetation characteristics with shoreline position on a tropical pocket beach

ABSTRACT Composition and richness of coastal vegetation differs with distance from the water and sheltering by topography. Transition from pioneer beach plants to mature forests is expected to be narrow on low wave energy coasts with a tropical climate favorable to vegetation growth. The goal of this paper is to determine whether vegetation on the beach and foredune will be denser and have a greater number of species and more woody shrubs near the water as wave and wind stresses diminish because of favorable shoreline orientation within a pocket beach. Field data on beach width, beach mobility, dune height, vegetation species, vegetation height and percent vegetation cover were collected in Puerto Rico along six cross-shore transects. Beaches are more stable at transects in the lee of an eolianite barrier and a tombolo. The vegetation gradient there is compressed, with denser, taller, more diverse vegetation and more tree species close to the waterline than at more exposed sites. The lack of mobility of the beaches and dunes and lack of geomorphically significant disturbance events is in contrast to the conspicuous feedbacks between overwash, topography, and vegetation on exposed mid-latitude coasts, revealing the need for more study of low-energy beach environments.

Multiphasic assessment of effects of design configuration on nutrient removal in storing multiple-pond constructed wetlands

As an important technology for purifying and recycling agricultural wastewater, storing multiple-pond constructed wetlands (SMCWs) are widely used in the treatment of non-point source pollution. However, the influences of design configuration (surface area, volume, flow path, aspect ratio, water depth, percent vegetation cover and planting pattern) on pollution mitigation in SMCWs are still underexplored. To improve the sustainability of constructed wetlands, the removal performances of four groups of SMCWs were assessed through multiphasic analyses. The maximum removal efficiencies of nitrogen and phosphorus were 63.7% and 64.0%, respectively. Higher mass removal rates per square meter (MRR) and mass removal rates per cubic meter (MRRV) were observed in ecological floating treatment wetlands (EFTWs). Compared with RE, the interception performances of deep-water SMCWs were more clearly described by using MRR and MRRV. EFTWs with good plant configurations (mixed planting, 60–80% plant cover) were recommended in deep-water SMCWs (water depth > 1.5 m).