Soil enzyme activity in an old-growth northern hardwood forest: Interactions between soil environment,ectomycorrhizal fungi and plant distribution

Plants and soil microbes produce extracellular enzymes (EE) that catalyze the hydrolysis of nitrogen (N) and phosphorus (P) containing compounds in soil and other enzymes involved in degradation of lignin and cellulose. We explored whether soil enzyme activity involved in carbon (C), N and P cycling were correlated with plant distribution, soil chemical conditions and the identity of fungi colonizing tree roots in an old growth forest remnant. Terminal restriction fragment length polymorphism (TRFLP) was used to determine the presence of root fungi and standard fluorometric analysis was used to determine soil enzyme activities. Soil enzymes were consistently positively correlated with soil C and N, but not CN ratio. Soil P was also correlated with enzyme activity during both June and September sampling. We saw no significant relationships between herbaceous plant cover and enzyme activity in June, but there were significant positive correlations between α-glucosidase and herbaceous plant coverage in September. We also found that some enzymes were significantly correlated with the identity of fungi colonizing tree roots separated from the soil cores. Chitinase and β-glucosidase were positively correlated with the genera Russula and Piloderma while chitinase was negatively correlated with Amanita and Entoloma. In addition, phosphatase was positively correlated with Russula, Meliniomyces and Solenopezia. Our results suggest that enzyme activity in old growth forest soils are affected by a variety of environmental factors, and that herbaceous plants and some root fungi may be associated with sites of elevated or decreased decomposition potential and nutrient cycling.     

Positive relationship between herbaceous layer diversity and the performance of soil biota in a temperate forest

The current decline in biodiversity is particularly pronounced in the herbaceous layer of forest ecosystems. We explored the relationship between a naturally occurring plant diversity gradient in the understory vegetation of a deciduous forest and several above-and belowground ecosystem processes. We show that particularly soil microbial parameters and microarthropod densities are positively correlated with plant species richness. These results confirm recent findings in grassland ecosystems and highlight the intimate interconnectance between the diversity and functioning of above-and belowground compartments. We conclude that irrespective of a potential causal relationship between plant species richness and belowground processes, it is essential to consider the performance of soil biota in order to understand the relationship between herbaceous layer composition and ecosystem function.     

Influence of long-term residue management on soil enzyme activities in relation to soil chemical properties of a wheat-fallow system

Summary Soil enzyme activities (acid and alkaline phosphatase, arylsulfatase, -glucosidase, urease and amidase) were determined (0- to 20-cm depth) after 55 years of crop-residue and N-fertilization treatment in a winter wheat (Triticum aestivum L.)-fallow system on semiarid soils of the Pacific Northwest. All residues were incorporated and the treatments were: straw (N₀), straw with fall burn (N₀FB), straw with spring burn (N₀SB), straw plus 45 kg N ha^–1 (N₄₅), straw plus 90 kg N ha^–1 (N₉₀), straw burned in spring plus 45 kg N ha^–1 (N₄₅SB), straw burned in spring plus 90 kg N ha^–1 (N₉₀SB), straw plus 2.24 T ha^–1 pea-vine residue and straw plus 22.4 T ha^–1 of straw-manure. Enzyme activities were significantly (P<0.001) affected by residue management. The highest activities were observed in the manure treated soil, ranging from 36% (acid phosphatase) to 190% increase in activity over the control (N₀). The lowest activities occurred in the N₀FB (acid phosphatase, arylsulfatase and -glucosidase) and N₉₀ treated soils (alkaline phosphatase, amidase and urease). Straw-burning had a significant effect only on acid phosphatase activity, which decreased in spring burn treated soil when inorganic N was applied. Urease and amidase activity decreased with long-term addition of inorganic N whereas the pea vine and the manure additions increased urease and amidase activity. There was a highly significant effect from the residue treatments on soil pH. Arylsulfatase, urease, amidase and alkaline phosphatase activities were positively correlated and acid phosphatase activity was negatively correlated with soil pH. Enzyme activities were strongly correlated with soil organic C and total N content. Except for acid phosphatase, there was no significant relationship between enzyme activity and grain yield.Journal Paper No. 8072 of the Agricultural Experimental Station, Oregon State University, Corvallis, OR 97331, USA     

Grasses, litter, and their interaction affect microbial biomass and soil enzyme activity

Plant effects on ecosystem processes are mediated through plant-microbial interactions belowground and soil enzyme assays are commonly used to directly relate microbial activity to ecosystem processes. Live plants influence microbial biomass and activity via differences in rhizosphere processes and detrital inputs. I utilized six grass species of varying litter chemistry in a factorial greenhouse experiment to evaluate the relative effect of live plants and detrital inputs on substrate-induced respiration (SIR, a measure of active microbial biomass), basal respiration, dissolved organic carbon (DOC), and the activities of β-glucosidase, β-glucosaminidase, and acid phosphatase. To minimize confounding variables, I used organic-free potting media, held soil moisture constant, and fertilized weekly. SIR and enzyme activities were 2-15 times greater in litter-addition than plant-addition treatments. Combining live plants with litter did not stimulate microbial biomass or activity above that in litter-only treatments, and β-glucosidase activity was significantly lower. Species-specific differences in litter N (%) and plant biomass were related to differences in β-glucosaminidase and acid phosphatase activity, respectively, but had no apparent effect on β-glucosidase, SIR, or basal respiration. DOC was negatively related to litter C:N, and positively related to plant biomass. Species identity and living plants were not as important as litter additions in stimulating microbial activity, suggesting that plant effects on soil enzymatic activity were driven primarily by detrital inputs, although the strength of litter effects may be moderated by the effect of growing plants.     

Changes of the functional diversity of soil microbial community during the colonization of abandoned grassland by a forest

The impact of secondary succession of grassland communities towards a Norway spruce forest on soil microbial community was studied on a belt transect established in the Pol’ana Mts., Central Europe. Data on understory vegetation, light availability, soil properties and microbial activity were collected on 147 plots distributed over regular grid. Moreover, distributions of functional groups of microorganisms were assessed using BIOLOG analysis on a subset of 27 plots. Mantel partial correlations between microbial community indicators and environmental variables showed that microbial activity generally decreased with increasing tree density and size, whereas it increased with increasing radiation at the soil surface, soil temperature, and cover and diversity of understory vegetation. Functional richness and diversity of microorganisms were positively correlated with solar radiation, but also with plant species richness and diversity. Abundance of several functional groups correlated closely with succession-related variables. Redundance analysis of microbial data provided slightly different outcomes. Forward selection yielded only two environmental variables significantly influencing the composition of the microbial community: tree influence potential and organic carbon content. Abundances of several functional microbial groups correlated with tree influence, documenting that microbial community changes are at least partially driven by the colonization of grassland by trees. Nevertheless, the relative importance of abiotic environment change and plant community succession on microbial community dynamics remains unresolved.     

Application of an insoluble polyacrylate polymer to copper-contaminated soil enhances plant growth and soil quality

Abstract. We investigated whether an insoluble polyacrylate polymer could be used to improve the quality of a copper-contaminated soil. Growth of annual medic ( Medicago polymorpha L.) was stimulated in the polymer-amended soil, such that total biomass produced was three times that of plants from unamended soil. Roots of plants cultivated in the polymer-amended soil had a concentration of copper that was 73% of that in plants from the unamended soil. Biological N₂ fixation was enhanced in the polymer-amended soil. Soil enzymatic activities at the end of the experiment were correlated with plant growth and copper concentration of plants grown in soils with different levels of copper, which were achieved by mixing the contaminated soil with varying proportions of a soil of low copper content. Shoot dry weight was positively correlated with acid phosphatase, β-glucosidase, β-galactosidase and urease, whereas copper concentration in the roots of the annual medic was negatively correlated with acid phosphatase, β-galactosidase, cellulase and urease. The results are consistent with soil remediation by the polyacrylate polymer. Soil quality as inferred from plant growth, biological N₂ fixation and soil enzymatic activities improved as a result of the remediation process.     

Legume–grass species influence plant productivity and soil nitrogen during grassland succession in the eastern Tibet Plateau

In recent years, numerous studies have evaluated the effect of plant function diversity on ecosystem functions such as productivity and soil nutrient status. We performed a redundancy analysis (RDA) to examine the relationship between plant functional diversity, productivity and soil nitrogen in a chronosequence of abandoned fields in sub-alpine meadow in the eastern part of the Tibet Plateau, China. We found that along the secondary succession sequence, legume richness and aboveground biomass significantly increased and both were positively correlated with total species richness (S) and aboveground biomass (T-bio). This pattern suggests that legume richness increases community productivity. In addition, we found that total aboveground biomass, legume and grass richness were positively correlated with soil microbial nitrogen (MBN), the ratio of microbial nitrogen to soil total nitrogen (MBN/TN) and the ratio of soil organic carbon and soil total nitrogen (C/N), whereas they were negatively correlated with soil total nitrogen (TN), organic carbon (C_org), and microbial carbon (MBC). Contrary to our predictions grasses such as Stipa grandis, Scirpus tripueter, Koeleria cristata were more closely associated with MBN, MBN/TN than legumes such as Oxytropis ochrocephala, Thermopsis lanceolate and Astragalus polycladus. The late-successional grass Kobresio humilis had a stronger positive correlation with NH₄-N as compared to the legumes and NO₃-N was not associated with any legume species. This suggests that the grasses and legumes have a synergetic positive influence on the ecosystem properties, especially nitrogen. Therefore, in this N-limited, plant community diversity of both legumes and grasses has a strong influence on ecosystem changes during succession.     

Species groups occupying different trophic levels respond differently to the invasion of semi-natural vegetation by Solidago canadensis

We studied the impact of the invasive plant species Solidago canadensis on the species richness of vascular plants and the abundance, species richness and diversity of butterflies, hoverflies and carabid beetles in herbaceous semi-natural habitats near Ljubljana, Slovenia. The species groups were sampled in sites dominated by S. canadensis and paired nearby sites covered by semi-natural vegetation. Plant species richness and species richness, abundance and diversity of butterfly species were lower in plots dominated by S. canadensis. Hoverfly abundance, diversity and species richness were negatively affected only in July just before the onset of flowering of S. canadensis, but tended to be positively affected in August during the height of flowering of S. canadensis. Only the abundance of carabid beetles was reduced in plots dominated by S. canadensis. The responses of the insect groups seem largely driven by the effects of Solidago on the availability of essential resources like food or larval host plants. Our results suggest that insect species that are closely related to plant species composition are more vulnerable to the effects of invasive plant species than those that are loosely or only indirectly related to plant species composition.     

Perennial energy cropping systems affect soil enzyme activities and bacterial community structure in a South European agricultural area

In recent decades, perennial rhizomatous grasses have been introduced in the Po Valley (Northern Italy), not only to produce bioenergy, but also to face the loss of soil organic carbon due to intensive crop management. Given the dual purpose of perennial energy crops, this work was intended to evaluate changes induced by the introduction of these crops on soil microbial community structure and on soil functionality. We compared a 9 year-old land conversion to two perennial energy crops, giant Miscanthus (Miscanthus sinensis × giganteus) and giant reed (Arundo donax L.), with two 40-year old annual arable systems, continuous wheat and maize/wheat rotation. The structure of the bacterial community was studied by the fingerprinting method of denaturing gradient gel electrophoresis (PCR-DGGE) amplifying 16S rRNA fragments, while the functional aspects of soil were investigated through the determination of three soil enzyme activities involved in soil carbon, nitrogen, and phosphorous cycles (β-glucosidase, urease, and alkaline phosphatase, respectively). Introduction of perennial energy crops positively stimulated the three soil enzymes, especially in the shallow soil layer (0–0.15 m), where accumulation of carbon and nitrogen was stronger. Enzyme activities were also positively correlated with organic carbon, apart from β-glucosidase. A significant but weaker correlation was also observed between enzyme activities and total nitrogen. The DGGE profiles revealed the relationship between crop types and soil microbial communities. Community richness was higher in perennial than in annual crops, but no effect of soil depth was observed. In opposition, Shannon index of diversity was not influenced by crop type, but only by soil depth with a 32% increase in the shallow layer. We conclude that the introduction of perennial energy crops in a South European soil increases both soil biochemical activity and microbial diversity, related to the ability of these crops to stabilize organic matter in soil. It is thereby evidenced that perennial rhizomatous grasses for energy uses could represent a sustainable choice for the recovery of soils depleted by intensive agricultural management.     

北江干流河岸带不同植被类型植物物种多样性分析

以北江干流河岸带4种典型植被类型(竹林、草地、混交林和桉树林)为研究对象,采用样方法调查分析其群落特征和物种多样性,运用冗余分析(RDA)探讨北江河岸带植物物种多样性与环境因子之间的关系。结果表明:北江河岸带植物物种受热带季风气候影响,植物种类繁多,共调查到59科116属136种植物,群落科属组成分散;4种植被类型的物种丰富度、Shannon-Wiener多样性和均匀度指数变化规律一致,均以混交林最高,竹林次之,桉树林最低,但各植被类型间差异并不显著,说明北江河岸带不同植被类型维持物种多样性的异质性较小,其作用更多体现在为不同物种提供栖息地;RDA结果显示,植物物种丰富度、均匀度和多样性指数与乔木层高度、草本层盖度和海拔均呈正相关,而与至河流距离和土壤含水量呈负相关,在选取的7个环境因子中,海拔对北江河岸带植物物种多样性的影响最大,土壤含水量影响次之,至河流距离影响最小。     

宁东矿区天然植物群落特征及其与土壤理化性质的关系

[目的] 研究宁东矿区天然植物群落特征与土壤理化性质的关系,为宁东矿区植被重建过程中植物种的选择提供科学依据。[方法] 以宁东矿区6种典型的天然植物群落和土壤为研究对象,采用野外调查结合室内试验的方法,对比分析不同群落的植物群落特征及其与土壤理化性质的关系。[结果] 宁东矿区6种天然植物群落共调查到植物55种,隶属于15科48属,集中分布于菊科、豆科、藜科和禾本科4科。细枝岩黄耆（Hedysarum scoparium）+柠条锦鸡儿（Caragana korshinskii）—白莲蒿（Artemisia sacrorum）群落灌木层植被盖度和高度在6个群落中均最高,其数值分别为48%和202.54 cm,灌木物种柠条锦鸡儿在其中5个群落中均有分布且生长良好。灌木层Patrick丰富度指数与土壤碱解氮、砾石含量、速效钾和有机质呈正相关,与pH值呈负相关;草本层植物种Patrick丰富度指数与土壤有机质、田间持水量和速效磷呈正相关关系。[结论] 宁东矿区煤矸石山植被重建时,对于覆土土质为壤质砂土或砂质壤土,优先选择柠条锦鸡儿、细枝岩黄耆、黑沙蒿（Artemisia ordosica）和沙拐枣（Calligonum mongolicum）等灌木树种;覆土土质为少砾质砂土时选沙冬青（Ammopiptanthus mongolicus）和柠条锦鸡儿;覆土土质为多砾质砂土时可选藏锦鸡儿（Caragana tibetica）、裸果木（Gymnocarpos przewalskii）和胡枝子（Lespedeza bicolor）等灌木物种。土壤容重对灌木物种多样性贡献率较大,土壤田间持水量和有机质对草本植物多样性贡献率较大。     

Dynamics of arbuscular mycorrhizal fungi and glomalin in the rhizosphere of Artemisia ordosica Krasch. in Mu Us sandland, China

To understand the ecological significance of arbuscular mycorrhizal (AM) associations in semi-arid and arid lands, the temporal and spatial dynamics of AM fungi and glomalin were surveyed in Mu Us sandland, northwest China. Soil samples in the rhizosphere of Artemisia ordosica Krasch. were collected in May, July and October 2007, respectively. Arbuscular, hyphal and total root infection and spore density of AM fungi peaked in summer. The mean contents of total Bradford-reactive soil proteins (T-BRSPs, TG) and easily extractable Bradford-reactive soil proteins (EE-BRSPs, EEG) reached maximal values in spring. Spore density and two BRSPs fractions were the highest in the 0-10 cm soil layer, but the ratios of two BRSPs fractions to soil organic carbon (SOC) were the highest in the 30-50 cm soil layer. Hyphal infection was negatively correlated with soil enzymatic activity (soil urease and acid phosphatase) (P < 0.05). Arbuscular infection was negatively correlated with soil acid phosphatase (P < 0.01). Spore density was positively correlated with edaphic factors (soil available N, Olsen P, and SOC) and soil enzymatic activity (soil acid and alkaline phosphatase) (P < 0.01). Two BRSPs fractions were positively correlated with edaphic factors (soil available N and SOC) and soil enzymatic activity (soil urease, acid and alkaline phosphatase) (P < 0.01). TG was positively correlated with soil Olsen P (P < 0.05). We concluded that the dynamics of AM fungi and glomalin have highly temporal and depth patterns, and influenced by nutrient availability and enzymatic activity in Mu Us sandland, and suggest that glomalin are useful indicators for evaluating soil quality and function of desert ecosystem on the basis of its relationship to AM fungal community, soil nutrient dynamics and carbon cycle.     

Arbuscular mycorrhizal fungal diversity along a Tibetan elevation gradient

Rhizosphere samples were taken from herbaceous plants along an altitudinal gradient on Segrila Mountain slope. Root colonization and spore biodiversity of arbuscular mycorrhizal fungi (AMF) from different altitudes were analyzed. Of the 146 plant species representing 45 families investigated, 72.2% of plant species were colonized by AMF and formed typical AM structures. A broad range of AM fungal taxa, 62 taxa representing all 4 orders of AMF were isolated from the soil. The composition of the AMF spore community was quite different at different positions along the elevation gradient. Some AM fungi, such as Scutellospora, preferred some specific elevations, or a range of elevation. Intensity of root colonization (M%) and spore density were negatively correlated with the altitude of the study sites. Species richness showed a decreasing trend with increasing elevation but the Shannon–Weiner index was unaffected by elevation. Isolate frequency and relative abundance of AMF also showed quite different distribution patterns among taxonomic families. The drivers of these changes in the AM fungal assemblages is not known and cannot be determined conclusively using such a comparative study along an environmental gradient.     

Soil enzyme activities in the rhizosphere of field-grown sugar beet inoculated with the biocontrol agent Pseudomonas fluorescens F113

Pseudomonas fluorescens F113, which produces the antimicrobial compound 2,4-diacetylphloroglucinol, is a prospective biocontrol agent. Soil enzyme activities were used to investigate the ecological impact of strain F113 in the rhizosphere of field-grown sugar beet. There were distinct trends in rhizosphere enzyme activities in relation to soil chemistry [determined by electro-ultrafiltration (EUF)]. The activities of enzymes from the P cycle (acid phosphatase, alkaline phosphatase and phosphodiesterase) and of arylsulphatase were negatively correlated with the amount of readily available P, whereas urease activity was positively correlated with the latter. Significant correlations between nutrient levels determined by EUF and enzyme activities in the rhizosphere were obtained, highlighting the usefulness of enzyme assays to document variations in soil nutrient cycling. Contrary to previous microcosm studies, which did not investigate plants grown to maturity, the biocontrol inoculant had no effect on enzyme activities or on soil chemistry in the rhizosphere. The results showed the importance of using homogenous soil microcosm systems, also employed in previous work, for risk assessment studies, whereby the effects of inherent soil variability were minimised, and effects of the pseudomonad on soil enzymology could be detected. Received: 3 February 1997     

Experimental drought reduced acid and alkaline phosphatase activity and increased organic extractable P in soil in a Quercus ilex Mediterranean forest

A six-year (1999–2005) experiment of drought manipulation was conducted in a Quercus ilex Mediterranean forest (Southern Catalonia) to simulate predicted climatic conditions projected for the decades to come. The aim was to investigate the direct and indirect effects of drought conditions on acid and alkaline phosphatase activity in soil and on P concentrations in soil, leaves and litter throughout the year. Soil acid phosphatase activity was higher than soil alkaline phosphatase activity. Drought reduced acid phosphatase activity in soil in all seasons, including summer and winter, the seasons with less biological activity due to water and cold stress. Reductions of soil water content between 13 and 29% reduced soil acid phosphatase activity between 22 and 27% depending on the season. Drought reduced alkaline phosphatase activity (by 28%) only in winter. Soil acid and alkaline phosphatase activities were positively correlated with soil water content in all seasons. In contrast short-term available-P which increased under drought in several seasons was weakly correlated with soil phosphatase activities. As a result, immediately/short-term available-P concentration ratios decreased in all the seasons (between 10 and 71%). Drought increased foliar P concentration and reduced the C/P concentration ratio in litter fall of the dominant tree Q. ilex. Drought also decreased the ratio between organic C and short-term available-P in soil. The results show that soil phosphatase activity is more directly dependent on changes in water availability than on changes in its substrate, short-term available-P. These effects of drought have several implications: the accumulation in the soil of labile P not directly available to plants, the increase in potential P losses from leaching and erosion during the torrential rainfalls typical of the Mediterranean climate, and changes in plant, litter and soil C:P stoichiometry that may lead to changes in soil trophic chains.     

The influence of land-use practices and economics on plant species richness in meadows

Thirty-one meadows were investigated within five sites representing various farming styles found in Austrian cultural landscapes. The meadows were analysed regarding (a) biodiversity (vascular plant and bryophyte species richness), (b) land-use practices (fertiliser input, mowing intensity, the use of silage), and (c) economic aspects (variable costs, profit margin and subsidies per ha). There were significant negative correlations between plant species richness and mowing intensity and intensity of fertiliser application. Bryophytes were good indicators of low nutrient regimes, having high species richness at low fertiliser input. Vascular plants showed highest species richness at an intermediate nitrogen supply. The total plant species richness decreased with increasing nitrogen supply. Intensive silage production was also negatively correlated with plant diversity. Species with a very narrow ecological niche of soil moisture and nutrients declined, whereas species adapted to wider ecological conditions increased. Profit margin and variable costs correlated negatively with plant species richness, with meadows that offered low or no profit margins showing highest species richness. There was no significant relationship between species richness and the amount of subsidies invested at the study meadows. Estimated costs of maintaining a species are shown. It is concluded that if plant species richness are to be maintained in these meadows, farmers have to receive increased financial incentives through agro-environmental subsidies for appropriate meadow management, and these have to be linked to clearly defined measures.     

矿区土壤丛枝菌根真菌对采陷时间序列的响应

煤炭井工开釆造成大面积的地表塌陷,破坏了原有地表植被、土壤结构和地貌,影响土壤微生物群落结构和组成.为了研究井工矿开釆沉陷区丛枝菌根真菌(AMF)多样性与开采时间序列的相关性,本文以补连塔矿区不同开采年份的采煤沉陷区作为样地,以AMF和土壤因子为研究对象,探索随着采煤沉陷时间的延续,AMF物种多样性、种群结构变化规律及...     

A microplate fluorimetric assay for the study of enzyme diversity in soils

A fluorimetric microplate enzyme assay has been developed to study enzyme diversity in soil as an approach to understanding functional diversity. The microplate assay allows a large number of soil samples and/or enzymes to be analysed in a short time. The substrates used are conjugates of the highly fluorescent compounds 4-methylumbelliferone (MUB) and 7-amino-4-methyl coumarin (AMC). The main advantage of using fluorimetrically-labelled substrates is that product formation can be measured directly in the microplate without previous extraction and purification of the product. A detailed protocol for this new technology is presented and some potential applications are outlined. A comparative study was carried out between the new microplate fluorimetric assay and a standard colorimetric enzyme assay based on p-nitrophenyl substrates. The kinetics of β-glucosidase and phosphatase activities were investigated in soils with different fertilizer backgrounds. Both methods generated similar values for V_max (maximum rate of activity) whereas the affinity of β-glucosidase and phosphatase for their respective substrates (as indicated by K_m values, Michaelis–Menten constant) was up to two orders of magnitude greater for the 4-methylumbelliferyl substrates compared to the p-nitrophenyl substrates.     

Effects of plant diversity on plant biomass production and soil macrofauna in Amazonian pastures

We examined the effect of plant diversity on plant production and soil macrofauna density and diversity. Four plants species (Arachis pintoi, an herbaceous legume; Brachiaria brizantha, a perennial grass; Leucaena leucocephala, a legume shrub; Solanum rugosum, a non-legume shrub) were used in a field experiment and communities of all combinations of one, two, three or four species were established. Plant diversity neither significantly affected density and diversity of soil macrofauna nor total plant biomass, however, the biomass of specific plants was negatively affected by plant diversity. Earthworm and ant densities were significantly higher in the presence of A. pintoi although this plant influenced neither the density of the other group nor fauna diversity. Earthworm and diplopod densities increased significantly with shoot biomass of A. pintoi. Fauna diversity increased significantly with shoot biomass (specific and total). Root biomass did not affect fauna density and diversity. Our results suggest that fauna density is affected by litter quality and that it is more affected by resource quantity than quality. Our results also confirm the importance of nitrogen fixers to ecosystem function.     

Enhancing vegetation diversity in glades, rides and roads in plantation forests

Permanent open spaces in plantation forests provide an opportunity for enhancing biodiversity in plantations and in the wider landscape. We surveyed vegetation in 60 glades, rides and roads in 12 Irish plantation forests, and collected data on solar radiation, soil and management. Variation in species richness and diversity of vascular plants and bryophytes was determined principally by soil factors and open space management. Light levels were positively associated with vascular plant species richness and negatively associated with richness of bryophytes. In rides, the most important plantation feature in determining solar radiation levels and plant diversity was ride width. Increasing edge-to-area ratio corresponded with a decrease in β-diversity within glades. Roadside plots most strongly influenced by road gravel and disturbance supported the highest vascular plant, open-habitat and ruderal species richness and vegetation evenness. For open spaces to contribute significantly to the biodiversity of plantation forests, rides and roads should be a minimum of 15 m in width and glades should be a minimum of 625-900 m² in area.