Description: Equipment for supplying hypersaturated dissolved oxygen (DO) into water without vertical mixing was installed at a depth of 13.8 m (1 m above the bottom) in the dredged area of polyhaline Lake Nakaumi. The vertical profile of dissolved sulfides, including H 2 S and HS − (ΣH 2 S), and the CH 4 concentrations in the water column and interstitial water of bottom sediment were investigated monthly during a period when hypersaturated DO water was delivered at a depth of 13.8 m. The area near the bottom was identified as oxic. H 2 S is easily and rapidly oxidized in an oxic environment through a chemical reaction with DO. Although the concentration of CH 4 in the experimental area was 95 % lower than that in the control area, CH 4 was detected, even though 20–220 % DO was observed near the bottom, where no H 2 S was detected. We can therefore confirm that supplying hypersaturated DO can improve the water quality, as well as the ecosystem, by preventing the evolution of H 2 S.

Description: It is important to determine the effects of vegetation on the water chemistry of headwater streams to ensure appropriate water resource management and landscape planning, particularly because vegetation is known to be one of the primary determinants of the chemistry in such streams and is easily altered by silvicultural operations. Previous studies of headwater stream water chemistry have investigated primarily the effects on baseflow. However, the sources and processes involved vary considerably between baseflow and stormflow due to rainfall. Stormflow water is supplied primarily through soil; accordingly, its chemistry is influenced by vegetation. The present study investigates the water chemistry of streams of headwater catchments, six with coniferous plantations and six with evergreen broadleaved forests, under four stormflow events and three times under baseflow conditions. The studied catchments were located in a hilly region in southwestern Japan and covered relatively small areas (0.7–3.6 ha). Inorganic ions, pH, and dissolved organic carbon were analyzed. A higher concentration of dissolved organic carbon and a lower concentration of Cl − were found in the broadleaved catchments compared to the coniferous catchments under stormflow conditions, but no differences were detected under baseflow conditions. For catchments with older forests, the NO 3 − concentration was higher in the coniferous catchments than the broadleaved catchments under stormflow conditions. These results indicate that these three constituents were not diluted during stormflow and that their presence in soil water may be affected by the type of vegetation. The observed increased NO 3 − concentration under stormflow conditions may result in higher loading downstream.

Description: Land-use allocation is an important way to promote the intensive and economic use of land resources and achieve the goal of sustainable development. It is a complex spatial optimization problem, and heuristic algorithms have been one of the most effective ways to solve it in past studies. However, heuristic algorithms lack the guidance of planning knowledge, which makes land-use patterns usually unreasonable in practice. This research proposes a spatially explicit genetic algorithm (SEGA) that integrates land-use planning knowledge with the genetic algorithm (GA). The SEGA transforms the spatially implicit computation mode of the GA into a spatially explicit optimization style, which helps to promote the effectiveness of regional land-use allocation. Gaoqiao Town, China, was selected as the study area to test the SEGA. Results show that: (1) land-use conversions are reasonable in accordance with planning knowledge, and they improve overall land-use suitability and spatial compactness; (2) compared with the GA, the SEGA is superior in achieving global objectives and simulating local dynamics. We demonstrated that planning knowledge is essential to heuristic algorithms for land-use allocation.

Description: The aim of this study was to examine the effects of accumulated soil salt on livestock production in Mongolian grasslands. In saline and control areas, we compared soil salinity, sodium concentrations in plants and wool, and body weights of ewes. Mean soil salinity, sodium concentrations, and growth retardation were greater in the high-salinity area than in the control region. Increased retention of sodium in wool samples was evidence of excess dietary sodium. These results reflect sodium overflow from soil to sheep via plants, and this overflow can diminish livestock productivity in saline areas.

Description: Tamarix ramosissima is a dominant species in desert riparian ecosystems in the western USA. It is a phreatophytic halophyte, with salt glands on the leaves. While osmoregulation is essential for turgor maintenance under high salinity, the dose–response relationship to salinity of various osmolytes in plants with salt glands is still unknown. We profiled crude leaf extracts of T. ramosissima to identify the metabolic compounds that contribute to its salt tolerance. We compared leaf cation, soluble sugar, amino acid, and betaine content among T. ramosissima samples from five points along the Colorado River. The leaf sodium content of T. ramosissima trees increased with increasing soil salinity. Under high salinity conditions, soluble sugar and betaine content did not increase, but amino acids did. The increase in proline accumulation was highly and positively correlated with leaf sodium content. Thus, proline appears to be the essential osmolyte that T. ramosissima accumulates in response to severe salt stress in desert riparian areas of the USA.

Description: The grass-free lawn is a novel development in modern ornamental horticulture where the traditional monoculture of grass is replaced by a variety of mowing-tolerant clonal forbs. It brings floral aesthetics and a diverse species approach to the use of lawn space. How the number of constituent forb species affects the aesthetic and structural performance of grass-free lawns was investigated using grass-free lawns composed of four, six and twelve British native clonal perennial forb species. Lawn productivity was seen to increase with increasing species number, but the relationship was not linear. Plant cover was dynamic in all lawn types, varied between years and was not representative of individual species’ floral performance. The behaviour of component species common to all lawns suggested that lawns with 12 species show greater structural stability than lawns with lower species number. Visual performance in lawns with the greatest species number was lower than in lawns with fewer species, with increasing variety in floral size and individual species floral productivity, leading to a trade-off between diversity and floral performance. Individual species were seen to have different aesthetic functions in grass-free lawns by providing flowers, ground coverage or both.

Description: Modernization of drainage systems is suspected of causing a deterioration in the biodiversity of paddy-dominated landscapes that are substitutes for natural wetlands. Here, we focused on the gray-faced buzzard ( Butastur indicus ), a top predator that inhabits agricultural landscapes in East Asia. We evaluated the impacts of drainage system modernization on buzzards by measuring reductions in paddy-dwelling frogs, a major prey for buzzards that are common in rice fields. Field surveys were conducted in yatsu valleys (“yatsu” refers to small, narrow valleys in which rice cultivation often dominates the valley bottom) in Shimane prefecture, western Japan. We found that the distribution of buzzards was positively correlated with the densities of black-spotted pond frogs ( Pelophylax nigromaculatus ) and forest green tree frogs ( Rhacophorus arboreus ), although the relationship between buzzards and pond frogs was stronger. In addition, pond frog density was negatively correlated with modern drainage systems, whereas tree frog density did not show such a pattern. Therefore, modern drainage systems may reduce the buzzard population indirectly by reducing pond frog densities.

Description: This study was conducted to assess the floral composition of the Alno communal mixed forest in the Philippines. A quadrat method of vegetational analysis was used for the assessment of trees, shrubs, saplings, and seedlings. A total of 78 species belonging to 43 families were identified in this communal forest. For the assessment of grasses, herbs, ferns, and other low-lying vegetation, the line intercept method was used. A total of 31 species belonging to 20 families were found using this method. The diversity (Shannon–Wiener) indices of this communal forest are 3.2129 and 2.3870 for the quadrat method and line intercept method, respectively. The most dominant species in this area is Pinus kesiya Royle ex Gordon (Benguet pine) with an importance value of 64.19 %. Endemic species in the area also connote ecological importance, being considered a good indication of the status of habitats and ecosystems of this communal forest.

Description: The number of avian species in urban areas throughout the world, particularly in Europe and the USA is low; however, their total density is higher than that observed in surrounding habitats. Nevertheless, it has not been confirmed whether this is true in Japan. Japanese cities have fewer green areas than European and American cities, and Japanese suburbs are likely to face forests on mountain slopes, whereas cities in most other countries face open grasslands, rural areas, or flatlands. These differences could influence the structure of avian diversity from city to native habitat. We compared the number of species and individuals of all species among city centers, suburbs, and forested areas in Japan. Similar to other countries, the structure of avian communities in Japanese cities was dominated by a handful of species, and total abundance was highest among the other environments. This suggests that the underlying mechanism determining the structure of the avian community is the same between Japan and other previously studied countries. However, species richness was not the highest in the intermediate areas, which is typical in Europe and the USA. This is because suburbs face forested areas and moderately urbanized areas are scarce in the study area. The lack of intermediate area is moderately typical in Japan. This difference is important not only for managing avian diversity but also total diversity from the city to native habitats in Japan.

Description: Quantification of landscape pattern is of primary interest in landscape ecological studies. For quantification purposes, a large number of landscape metrics have been developed, with definitions based on measurable patch attributes. Calculation of these metrics is commonly conducted on wall-to-wall maps, whereas a new interest is to use sample data. It is argued that a sample survey takes less time and results are more reliable. The overall objective in this paper was to present the potential of the line interest sampling method for estimating a special contagion metric. The specific objective was to assess statistical properties in terms of root mean square error (RMSE) and bias of the contagion metric estimator. This study was conducted on 50.1 km 2 already manually delineated land cover maps from the National Inventory of Landscape in Sweden. Monte-Carlo sampling simulation was employed to assess the statistical properties of the estimator. The simulation was conducted for different combinations of two sampling designs, four sample sizes, five lines transect configurations, three lines transect lengths, and two classification systems. The systematic sampling design resulted in lower RMSE and bias compared to a simple random one. Both RMSE and bias of the contagion estimator tended to decrease with increasing sample size and line transect length. We recommend using a combination of systematic sampling design, straight line configuration and long line transect. We conclude that there is no need to use mapped data and thus polygon delineation errors can considerably be reduced or eliminated.