Permanent Vegetation Research Articles

Phytoremediation Potential of Crop Plants in Countering Nickel Contamination in Carbonation Lime Coming from the Sugar Industry.

The phytoremediation potential of four crop species cultivated on carbonation lime coming from the sugar industry with water-soluble nickel (Ni) exceeding the Italian legal limit of 10 µg L−1 was assessed. Two autumn–winter species (spinach and canola) were tested with and without the addition of bentonite in a greenhouse experiment in order to overcome prolonged unfavourable weather conditions. Two spring-summer species (sunflower and sorghum) were grown in outdoor boxes. Plant species were selected among crops of interest for phytoremediation and their rotation throughout the year enable to maintain a permanent vegetation cover. Nickel concentration in different plant tissues and the concentrations of soluble and bioavailable Ni in lime were measured. In the greenhouse study, soluble Ni decreased below the legal limit in all the tests, and the combined effect of bentonite and plants reduced Ni in lime mainly in the bioavailable fraction. Spinach and sunflower emerged to be more suitable for phytoextraction than canola and sorghum, because of the higher concentration of the metal in the epigeal portions. The results from the outdoor experiment highlighted that sorghum has a good phytostabilisation potential since its ability to accumulate Ni mainly at the root level and to attract a significant amount of bioavailable Ni in the rhizosphere. This study arose from a real scenario of environmental contamination and investigated the potential of different approaches on the bioremediation of a specific industrial waste product.

Permanent vegetation distribution: indicators of watershed management

Watershed management aims to improve or restore and or protect the carrying capacity of watersheds, especially to maintain the preservation of water systems, increase land productivity and improve community welfare. This can be done by controlling the factors causing land degradation. Erosion is one of the causes of degradation can be controlled by managing land use to suit its capabilities. The more areas that are not suitable for their capability will reflect the failure of land management. The sloping area (slope > 15%) should be covered by permanent vegetation such as, are shrub, secondary forest, plantation forest, and plantation. If the proportion of sloping areas covered by permanent vegetation compared to the total sloping area is very small (<50%) then it can be said that land management activities are less successful, because, in reality, these areas are relatively more vulnerable to erosion. This condition provides information that in these erosion-prone areas, land cover needs to be improved. In this way in addition to the area, the distribution of permanent vegetation can also be known. The spatial distribution of permanent vegetation at sloping locations that are upstream of a watershed/sub-watershed can be seen clearly.

The pattern of agricultural plant types based on cultivated land region and soil types in the Mount Patuha area

Indonesia is an agrarian country with agrarian society producing and maintaining crops and farmland. Most of the agrarian society in Indonesia is concentrated in the Java island. The Mount Patuha Area in West Java is considered to be a suitable area for agriculture. In May 2017, there has been erosion and major flood lately due to annual crop changed to seasonal crops in the Mount Patuha Area. This study aims to analyze spatially the suitability of agricultural plant types based on the WTU concept and soil types to prevent environmental damage from happening again and maintaining the sustainability of the agricultural sector. The Cultivated Land Region concept is also known as “Wilayah Tanah Usaha” (WTU) in Indonesia is an approach to manage agricultural land properly and sustainably based on the land elevation and slope as limiting factor from soil damage. Soil type also determines the plant suitability. This study is utilizing Geographic Information System (GIS) to overlay spatial data in the form of a DEM, soil types, and land use. The results show that WTU category in Patuha Mount Area is dominated by Second Main Area and Second Restricted Area, with soil type dominated by cambisol and the dominant plant type is tea plantation. This study concluded that there are still many agricultural plant types that are not in line with the WTU concept. The WTU concept is suitable to be applied in the Mount Patuha area as long as the farmers can adapt their land management by balancing with soil conservation technique such as make terracing on steep slopes and maintaining the second restricted area in permanent vegetation conditions.

Assessing vegetation recovery in reclaimed opencast mines of the Teruel coalfield (Spain) using Landsat time series and boosted regression trees

Opencast mining is an activity that caters to many economic sectors; however, it has a large impact on society and the environment. After mining, the major concern is to restore the previous land cover, which was generally a natural vegetation cover. Establishing permanent vegetation cover can restore landscape connectivity and previous ecosystem functions, enhance aesthetic values and prevent off-side effects associated with post-mining landscapes. Opencast mining reclamation deals with these issues with several strategies that aim to develop a vegetation cover after mining activity has stopped. However, not all reclamation actions are effective, and assessing their efficiency by monitoring vegetation development at reclaimed sites is a time-consuming task because it usually involves extensive field work. In this study, we present a semi-automatic approach based on analysing satellite data (Landsat) time series and using a machine learning technique to identify suitable conditions for vegetation development at reclaimed opencast mines. We analysed the Teruel coalfield (Aragón, central-eastern Spain). This area is a representative Mediterranean-Continental region that is of particular interest due the diversity of reclamation actions that have been applied and the increase in drier conditions during the last decades. Conditions were described with topography derived variables, technical reclamation features and drought-occurrence variables as potential explanatory factors. The implemented approach allowed us to identify the main abiotic filters for vegetation of this geographic region: the water availability and soil retention (both controlled by the topographic slope), and the proximity to seed sources. The analysis evidenced the negative influence of drought occurrence on vegetation development, and different responses were found depending on the timescale at which drought is calculated. Our results indicate that the reclamation landform model is the main key factor influencing vegetation development. A model such as the smooth berm-slope increases water availability and controls soil erosion, and hence, improves vegetation development. In addition, we found that further than 500-600 m from the mine, the effect of seed source declines dramatically. Therefore, all these issues should be considered in future reclamation designs in a Mediterranean-Continental environment. Our methodology could be adapted to other geographic regions where spatial environmental data are available.

Spiders in rice-paddy ecosystems shift from aquatic to terrestrial prey and use carbon pools of different origin

Spiders are important bio-control agents of rice insect pests such as plant- and leafhoppers. To investigate temporal changes in spider prey and variations in prey due to landscape structure around rice fields, carbon and nitrogen stable isotopes of rice field arthropods were analysed over three consecutive sampling dates during the rice cropping season. Initial isotope composition of gnats and midges emerging from submersed rice fields indicates a larval algae diet, while later values suggest a switch to rice-derived carbon. Initial δ13C values of plant- and leafhoppers were higher in fields of rice-heterogeneous landscapes, indicating migration from source populations feeding on C4 grasses into rice fields; later, their δ13C values approached those of rice. Isotope values of web-building and cursorial spiders in the earliest samples indicate aquatic gnat and midge prey. The later shift toward terrestrial herbivore prey was more pronounced for small than for larger species and in rice paddies near permanent vegetation, indicating use of prey from the surrounding landscape. The results suggest that rice field spiders are supported by three different carbon pools: (1) aquatic carbon originating from algae and (2) legacy carbon from previous growing cycles, both incorporated via between-season predation on gnats and midges, and (3) carbon from the current rice season incorporated via herbivore prey. In conclusion, fostering aquatic midge and gnat larvae, e.g. via mulching, and integrating rice fields into rice-heterogeneous landscapes likely strengthens biological control of pest species in rice paddies by supporting high populations of spiders between cropping seasons.

Body size and habitat use of the common weasel Mustela nivalis vulgaris in Mediterranean farmlands colonised by common voles Microtus arvalis

Small mustelids such as weasels are highly specialized predators of small rodents. Their diminutive size allows hunting for prey underground, but also means that they are “bite-sized” predators, preyed upon by other larger predators. Habitat use by weasels is therefore expected to depend not only on prey abundance, but also on predation risk. We report here on the body size and habitat use of common weasels Mustela nivalis vulgaris captured in intensive farmlands of northwest Spain during 2009–2015. We show that weasels’ capture rate was higher in field margins than in other habitats (cereal and alfalfa fields, fallows) irrespective of season. All small mammals (common vole, wood mouse, Algerian mouse, and greater white-toothed shrew) were consistently more frequently captured in field margins than other habitats. Weasel capture rate in each habitat was proportional to that of prey in these (alfalfa > fallows > cereal), except for field margins, which were used more intensively than expected from prey capture rate. Weasel capture rate was 37% lower in areas provided with nest boxes to increase local raptor abundance, a reduction that occurred in all habitats and was significant when correcting for prey capture rate. Weasel habitat use reflected a trade-off between prey abundance (bottom-up control) and predation risk (top-down control), with a preferential use of field margins that offer not only more prey but also permanent vegetation cover and protection from avian predators throughout most of the annual crop cycles. Weasel and vole head width data show that voles are not safe underground from smaller female weasels and that burrow entrances were wide enough for weasels to escape underground from predators. In NW Spain, common voles are a main farmland pest causing significant impacts. We discuss the implications of current vole control measures for weasels in areas recurrently affected by vole outbreaks.

Vegetation management intensity and landscape diversity alter plant species richness, functional traits and community composition across European vineyards

Land-use intensification at the field and landscape scale is a strong driver for declining biodiversity and ecosystem service provision. Vineyards are characterised by non-productive inter-rows, which could potentially host diverse plant communities. Mulching, tillage or herbicides are used to mitigate the competition between vines and the inter-row vegetation. As plant species with the same set of functional traits will respond similarly to environmental filters like management measures, knowledge about plant trait–environment-relations can be used to predict community and ecosystem processes which are essential for preserving ecosystem services like soil erosion mitigation. We hypothesized that higher vegetation management intensity reduces plant (functional) diversity, changes functional traits and community composition.Across Europe, four viticultural regions in Austria, France, Spain and Romania, which comprised 78 vineyards differing in vegetation management intensity (bare soil, temporary and permanent vegetation cover), were selected for sampling vascular plant diversity. Around each vineyard, the surrounding landscape composition and landscape diversity was investigated within a 750m radius. Rao's quadratic entropy as a measure of functional diversity was calculated based on a selection of plant functional traits. The effects of management and landscape variables on species richness, functional traits, functional diversity and vegetation cover were analysed by generalized linear mixed models and random forests (RF). Furthermore, plant community composition was analysed with non-metric multidimensional scaling (NMDS).Higher management intensities resulted in lower species richness, functional diversity and vegetation cover. The country with the related divergent edaphoclimatic conditions was a significant factor affecting most diversity and functional trait parameters, whereas landscape diversity increased plant species richness only slightly. Vegetation management intensity had the highest explanatory power for species richness, functional diversity and most functional traits according to RF analysis. Consequently, plant functional traits like a higher coverage of ruderals and annuals could be clearly related to bare soil management. Furthermore, the type of cover crops influenced the relationship between annual and perennial plant species, Grime plant strategy types and species diversity. Accordingly, NMDS showed a separation between permanent vegetation cover and bare soil vineyards. The overall positive effect of extensive management and the use of diverse cover crops or spontaneous vegetation in vineyard inter-rows should be better implemented in agricultural policies to support both, biodiversity and ecosystem provision.

Impact of willow-based grassland alley cropping in relation to its plant species diversity on soil ecology of former arable land

Effects of silvo-arable alley cropping systems (ACS) on soil functions have frequently been investigated, however, less is known about the effects of silvo-grassland ACS. Conversion of arable land to grassland ACS may have a high capability to rebuild soil fertility, while increased grassland plant diversity may further foster improvements. The objective of the study was to assess the impact of willows (Salix spp.) and grassland plant species diversity on soil ecology of an ACS established on former arable land. Thus, soil quality indices, like soil organic carbon (SOC), microbial biomass C and N, fungal abundance and microbial functional diversity, were quantified in formerly ploughed Eutric (Stagnic) Cambisols in two soil depths (0–5, 5–20 cm) of a temperate grassland ACS (Lower Saxony, Germany). To evaluate potential tree effects on alleyways, distance transects were analysed by repeated measures mixed effects models, considering abiotic factor (pH, clay content) variability. Possible changes of soil quality indices within the former ploughed soil layer were deduced by a comparison of both soil depths at each distance. Linear contrasts were calculated for comparisons of grassland diversity levels. Results showed significantly higher SOC contents (16.2–16.9 mg g−1) and soil microbial properties (e.g. MBC: 453-462 μg g−1, ergosterol: 4.3-4.4 μg g−1) in upper topsoils under trees and grassland compared with lower topsoil layers (11.6–12.0 mg g−1, 262-277 μg g−1 and 1.7-1.8 μg g−1 for SOC, MBC and ergosterol, respectively). No effects of plant species diversity on microbial properties have been detected to date. Similar levels of soil quality indices in upper topsoils under trees and grassland are ascribed to the cessation of tillage and a permanent vegetation cover ongoing for 5 years, as aboveground tree litter inputs into the alleyways were minor. Hence, irrespective of the diversity level of grassland vegetation, grassland ACS may have a high potential to increase soil quality for matching the requirement of sustainability of agroecosystems. However, as solely topsoils have been investigated, henceforth, the consideration of subsoils is vital to assess the effect of deep tree roots in grassland ACS.

Five new records of Pyrenula (Pyrenulaceae) for New Zealand

ABSTRACTPyrenula (Pyrenulaceae) is a poorly studied genus of lichenized mycobiota in New Zealand. Following the sampling of lichens from over 50 vegetation plots established within the Auckland Region by the Auckland Council, we have recognised a further five species of Pyrenula: P. leucostoma (Zahlbr.) R. C. Harris, P. microcarpa Müll. Arg., P. pyrenuloides (Mont.) R. C. Harris, P. subumbilicata (C. Knight) Aptroot and P. subvariolosa (C. Knight) Aptroot from the New Zealand Botanical Region. These discoveries increase the number of Pyrenula accepted for New Zealand from 10 to 15, and extend the range of two species previously regarded as endemic to Australia. The discoveries also highlight the importance of undertaking more comprehensive lichen sampling within New Zealand’s ecosystems. We recommend that, for those regions where permanent vegetation plots have been established for long-term monitoring, an assessment of lichen diversity should also be included in their initial sampling phase and monitoring protocols. With these additions, as well as changes in the taxonomy of New Zealand Pyrenula, a revised key to the known species of Pyrenula in New Zealand is presented.

A Regression Model of Stream Water Quality Based on Interactions between Landscape Composition and Riparian Buffer Width in Small Catchments

Riparian vegetation represents a protective barrier between human activities installed in catchments and capable of generating and exporting large amounts of contaminants, and stream water that is expected to keep quality overtime. This study explored the combined effect of landscape composition and buffer strip width (L) on stream water quality. The landscape composition was assessed by the forest (F) to agriculture (A) ratio (F/A), and the water quality by an index (IWQ) expressed as a function of physico-chemical parameters. The combined effect (F/A × L) was quantified by a multiple regression model with an interaction term. The study was carried out in eight catchments of Uberaba River Basin Environmental Protection Area, located in the state of Minas Gerais, Brazil, and characterized by very different F/A and L values. The results related to improved water quality (larger IWQ values) with increasing values of F/A and L, which were not surprising given the abundant similar reports widespread in the scientific literature. But the effect of F/A × L on IWQ was enlightening. The interaction between F/A and L reduced the range of L values required to sustain IWQ at a fair level by some 40%, which is remarkable. The interaction was related to the spatial distribution of infiltration capacity within the studied catchments. The high F/A catchments should comprise a larger number of infiltration patches, allowing a dominance of subsurface flow widespread within the soil layer, a condition that improves the probability of soil water to cross and interact with a buffer strip before reaching the stream. Conversely, the low F/A catchments are prone to the generation of an overland flow network, because the absence of permanent vegetation substantially reduces the number of infiltration patches. The overland flow network channelizes runoff and conveys the surface water into specific confluence points within the stream, reducing or even hampering an interaction with a buffer strip. Notwithstanding the interaction, the calculated L ranges (45–175 m) are much larger than the maximum width imposed by the Brazilian Forest Code (30 m), a result that deserves reflection.

Characterization of Nutrient and Metal Leaching in Roadside Ditches Maintained with Cool and Warm Season Grasses

Roadside ditches play an important role in the quantity and quality of receiving waters. Very little, however, is known about the fate and transport of nutrients and trace metals in roadside ditches, especially their leaching to shallow groundwater. This study sought to document selected water quality constituent levels in infiltrated water (i.e., leachate) in roadside ditches maintained with permanent vegetation. Leachate sampling wells were installed in four roadside ditches, and water samples were collected from the wells following major rainfall events during the years 2016 and 2017. The samples were analyzed for nutrient and metal concentrations. Results indicated that nutrient concentrations in the water samples range from 0.00600 to 0.0107 mg/L for orthophosphate (PO4–P), 0.00500 to 6.80 mg/L for nitrate (NO3–N), 0 to 0.007 mg/L for nitrite (NO2–N), and 0.0100 to 314 mg/L for chloride (Cl−). Concentrations of the metals examined varied between 0.0100 and 104 mg/L in water samples. While there was no specific pattern in both nutrient and metal concentrations when roadside ditches maintained with cool season grass were compared to those of warm season grass ditches, results suggest that grass types will likely affect differently uptake of nutrients and metals in the ditches.

Runoff, soil loss, and sources of particulate organic carbon delivered to streams by sugarcane and riparian areas: An isotopic approach

Soil erosion leads to land degradation and translocation of soil particles together with associated particulate organic carbon (POC) and nutrients, thereby influencing the global carbon cycle. In the present study, we estimated the contribution of POC delivered to a first-order stream from upslope sugarcane fields and a riparian forest in southeast Brazil. The results show that the amount of surface runoff and soil erosion generated in the riparian forest is significantly lower than in the upslope sugarcane field. However, the contribution of the forest to the total stream bed POC was above 70%, even though most sediments delivered to the stream originated from the upland sugarcane fields. The discrepancy between sediment and POC delivery from both land uses is a consequence of the presence of preferential runoff pathways from the agricultural fields, through the buffer strips, to the stream. This disconnection between the main sources of sediment and POC to the first-order stream is a potentially important mechanism influencing the transfer of POC from upslope areas to waterways. This mechanism should be considered in order to more reliably assess fluxes of OC from upslope areas to first-order streams in landscapes where arable land is separated from streams by a semi-natural buffer zone with permanent vegetation.

Earthworms as useful bioindicator of soils contamination around Košice city, Slovakia

Abstract This study was conducted to investigate heavy metals bioaccumulation in industrialized soils in surrounding of Košice city (Slovakia), using earthworms. In the present research, we used ecotoxicity tests with Dendrobaena veneta (7 and 28-day bioassays) to infer about potential toxic risks to the agricultural (A) and permanent grass vegetation (PGV) of soils around the plant U. S. Steel Košice. The total Fe, Cu, Zn, Pb, Cd, Cr and As contents and eco-toxicological tests of industrialized soils from the Košice area were performed for 12 sampling sites in years 2016 – 2017. An influence of the sampling sites distance from the largest steel producer plant on the total concentrations of heavy metals was determined for Fe, Cd, Cr and As. It was found that earthworms (Dendrobaena veneta) in some cases caused a decrease of metals concentration in contaminated soils, the largest metal concentration differences were recorded in the samples PGV (4) U. S. Steel-plant-main gate. The results of the bioaccumulation factors of heavy metals in D. veneta (BAFs/7-28 d) are &lt; 1 for the studied metals order in the sequence: Cr &lt; Fe &lt; Pb &lt; Cu &lt; As and &gt; 1 for Zn &gt; Cd.

Rapid changes in eastern Himalayan alpine flora with climate change.

With biodiversity and rates of climate change among the highest, the eastern Himalaya are critical for understanding the interaction of these two variables. However, there is a dearth of longitudinal data sets that address the effects of climate change on the exceptional alpine biodiversity of the Himalaya. We established permanent alpine vegetation monitoring plots in three mountain chains of the Hengduan Mountains, the easternmost Himalaya, which have warmed 0.03-0.05°C yr-1 since 1985. Recently, we resampled plots (176 1-m2 quadrat plots and 88 sections of 11 summits in three Hengduan mountain chains) to measure changes in vegetation after 7 years. Over 7 years, Tibetan alpine vegetation increased in number of species (+8 species/summit; +2.3 species/m2 ), in frequency (+47.8 plants/m2 ), and in diversity (+1.6 effective species/m2 ). Stepwise regressions indicated that warmer temperatures, southerly aspects, and higher elevations were associated with greater increases in these vegetation metrics. Unexpectedly, Himalayan endemic species increased (+1.4 species/m2 ; +8.5 plants/m2 ), especially on higher-elevation summits. In contrast, the increase in relative abundance of non-alpine species was greater at lower-elevation summits. Plants used by local Tibetans also increased (+1.3 species/m2 ; +32 plants/m2 ). As in other alpine areas, biodiversity is increasing with climate change in the Himalaya. Unlike other areas, endemic species are proliferating at the highest summits and are indicators of change.

Early responses of vascular plant and bryophyte communities to uniform shelterwood cutting in hemiboreal Scots pine forests

Shelterwood (SW) cutting is considered a sustainable harvest method but its impact on understorey diversity of Scots pine (Pinus sylvestris) forests has not been thoroughly studied. Our aim was to clarify how uniform SW cutting in interactions with soil scarification, deposition of logging residues and altered light conditions affects the species richness and composition of vascular plants and bryophytes and how different species groups and individual species vary in their responses to SW practices. We monitored permanent vegetation plots in nine mature pine forests of hemiboreal Estonia before, shortly after and 3–4 years after SW harvesting. The results indicated that the effect of uniform SW harvesting was species group specific as the majority of vascular plant species groups as well as mosses and epigeic bryophytes increased in richness, however, the species richness of epiphytic and epixylic bryophytes decreased. Late-successional species showed two types of responses to SW harvesting: either reduction of cover or reduction followed by a recovery. Soil scarification favoured early-successional bryophyte species as well as the richness of tree seedlings and dwarf-shrubs but diminished the cover of Vaccinium myrtillus, Vaccinium vitis-idaea and Hylocomium splendens. The harvest-induced changes in the species composition were more pronounced for bryophyte communities than for vascular plants. Retention of green trees and dead-wood is important in SW harvesting for sustaining the vulnerable epixylic and epiphytic bryophyte species. To summarise, uniform SW harvesting increases the species richness of vascular plant and bryophyte communities in pine forests - at least in the short term.

Emergent wetland vegetation data recording: Does an optimal period exist?

AbstractAimsCertain parts of the growing season have been proposed as optimal for recording relevant relevés of forests and dry grasslands and so the monitoring of these vegetation types has become more time‐ and cost‐effective. We investigated whether it is possible to propose an optimal period during the year for making relevant relevés of emergent wetland vegetation.LocationMarshlands of the central Balkan Peninsula.MethodsOne hundred and eighty‐five permanent vegetation plots were investigated in three distinct time periods: spring, summer and autumn. In order to identify the communities, cluster analyses were carried out, and diagnostic species for each cluster were determined. The potential for temporal change of the communities regarding the species and life form composition was assessed using PERMANOVA and NMDS analyses. The Friedman test was used to assess the significance of seasonal change in the communities regarding their species richness, recordability and Shannon diversity.ResultsThe level of floristic similarity among the 11 phytocoenoses analyzed significantly varied over the growing season while the composition in terms of their diagnostic species remained unchanged. The majority of the communities showed statistically significant seasonal changes in the qualitative and quantitative characteristics of the vegetation, life form composition and cover. Although different communities expressed significant modifications in these parameters between different pairs of seasons, all of them showed changes in the mentioned parameters between spring and autumn. The degree of intra‐annual variation in the species richness, species recordability and Shannon diversity was low in almost all phytocoenoses.ConclusionsSummer is the optimal period for recording most of the species from the total list of the communities developed on hydrologically stable habitats, while spring is more appropriate for making relevés on periodically inundated habitats. The sampling time has negligible impact on the classification of associations but it could have important implications for the classification of higher‐ranked syntaxonomic units of the class Phragmito‐Magnocaricetea.

Geographic information systems in the delimitation of permanent preservation areas and vegetation index on the Jequitinhonha Valley municipality

Geographic information systems in the delimitation of permanent preservation areas and vegetation index on the Jequitinhonha Valley municipality

The role of soil-protecting forests in reducing soil erosion in young glacial landscapes of Northern-Central Poland

The use of phytomelioration in environmental management, particularly in case of long-term, permanent forest vegetation, is one of the most natural and effective ways to mitigate the effects of soil erosion. Forests in general have a very effective protective function. The paper identifies differences in the basic soil properties along slope surfaces, in relation to the land use. Moreover, the role of soil-protecting forests in reducing the intensity and effects of soil erosion processes was assessed. The research was conducted in the young glacial landscape of north-central Poland. Analysis of soil catenas along the slopes and of material collected from the soil pits revealed that the forests highly protect against the degradation of soil cover, especially, in limiting, among others, loss of humus and the reduction of upper soil horizons. On the slopes under forests, clear changes in particle size distribution in relation to the adjacent slopes used for agricultural purposes were observed.

Soil and water conservation measures reduce soil and water losses in China but not down to background levels: Evidence from erosion plot data

The efficacy of soil and water conservation measures (SWCMs) on reducing the loss of soil and water has been widely tested at the plot scale in China. However, an integrated comparison of the efficacy and an overall investigation of the controlling factors of the efficacy is absent. Therefore, an extensive dataset compiling erosion plot measurement of applying SWCMs on controlling soil loss and runoff in China was established in this study. In total, 848 erosion plots representing 2494 plot years were retained in this dataset which compiled from 108 publications and 2 data reports. The 15 most frequently tested SWCMs were identified and described. Soil loss ratio (SLR) and runoff ratio (RR) of each SWCMs was calculated to assess the efficacy of an SWCMs on reducing soil and water loss. The potential controlling factors, such as slope, slope length, annual precipitation, were evaluated for the controlling factor for both SLR and RR. Our results suggested that in general, applying the SWCMs can reduce soil loss by ca. 70% (overall SLR is 0.39 ± 0.02) and runoff by ca. 50% (overall RR is 0.54 ± 0.05), respectively. However, erosion rates on plots with SWCMs in China were, in general, still significantly higher than erosion rates measured under permanent vegetation cover land and, on average, ca. one order of magnitude higher than soil formation rates which required for a soil-neutral agriculture. On overall, the SLR presented a significant relation with topographic factors: positive with slope gradient and negative with slope length. This suggests that the support practice factor (P factor) of RUSLE model might be overestimated when values measured from plot scale are directly applied to larger areas (catchment or region scale). The SLR and RR values presented in this study can be applied for the planning of SWCMs in China and can be used to estimate the P factor when applying RUSLE model whereby the effect of topographic factors on SWCM efficacy can be accounted for.

Landscape context is more important than wetland buffers for farmland amphibians

In regions with high rates of wetland loss, remnant wetlands and constructed ponds can provide important breeding habitat for amphibians. However, such wetlands are often embedded in a matrix of agricultural fields, potentially putting species within these wetlands at risk. One recommendation for conservation of amphibians in agriculture-dominated landscapes is to maintain a buffer of permanent vegetation around the wetland. However, it is not clear how wide wetland buffers must be to effectively conserve amphibians in agriculture-dominated landscapes or what vegetation types are suitable buffer vegetation. Furthermore, it is not clear whether wetland buffers produce similar—or better—conservation outcomes for amphibians than actions conducted at larger spatial extents. We addressed these questions using data from anuran (frog and toad) breeding call surveys in 36 wetlands in rural eastern Ontario, Canada. First, we tested for the effects of 49 different wetland buffer measurements on anuran richness, relative anuran abundance, and the abundance/probability of occurrence of individual species. These 49 measurements represented all combinations of seven different ways to measure the wetland buffer size and seven types of buffer vegetation. Wetland buffer size was measured as the minimum width of buffer vegetation contiguous with the wetland and proportion of the area within 5, 16, 30, 50, 120, or 300 m of the wetland containing buffer vegetation that was contiguous with the wetland. Then, to compare the strength of effect of wetland buffers versus landscape context on anurans, we compared the wetland buffer measurement with the strongest positive effect on each anuran response (from the previous analysis) to the effects of three landscape-scale variables: area of woodland; area of wetlands, streams, rivers, and lakes; and road density. We did not detect positive effects of wetland buffers on anuran richness or relative anuran abundance. This is because positive effects of wetland buffers on individual species were rare, i.e. positive effects were only supported for two of the six species with enough data to model individually: American toads (Anaxyrus americanus) and green frogs (Lithobates clamitans). Furthermore, we found that the landscape context had much stronger effects on relative anuran abundance than the wetland buffer, with effect sizes ranging from 4 (road density) to 14 (woodland cover) times that of the wetland buffer. These findings suggest that guidelines for anuran conservation in agricultural landscapes should generally focus on protection of terrestrial habitat at the landscape scale rather than on maintenance of wetland buffers.