Macro‐ and micronutrients removed by upland and lowland rice cultivars in West Africa

Abstract

Plant analysis is an important component of soil fertility and plant nutrition research. Plant analysis at harvest of the crop forms the basis for constructing nutrient balances and assessing the nutrient needs of production systems. Amounts of macro‐ and micronutrient elements removed by improved, upland and lowland rice cultivars were determined in field experiments at two sites in Ivory Coast. Amounts of nitrogen (N), zinc (Zn), and manganese (Mn) removed for 11 rice grain yield by upland and lowland rice cultivars were similar, but the amounts of phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) removed were higher for lowland than upland rice. The nutrient element harvest indexes (amount in grain/amount in grain plus straw) varied between the cultivars, but more importantly, among nutrient elements. On average the nutrient harvest index was highest for P (69%) and lowest for K (10%). The results suggest that the nutrient requirement of rice for K can be met to a large extent through the recycling of K in rice straw. The amounts of other major nutrients, N and P in the straw were small and hence less scope for supplying these nutrients through the recycling of rice straw.     

Fifty years of change in Central European grassland vegetation: Large losses in species richness and animal-pollinated plants

There is growing concern that biodiversity loss in European agricultural landscapes is having negative effects on functional trait diversity. Long-term studies examining vegetation changes from the period before agricultural industrialisation are however rare. Here, we ask how management intensification and increased nutrient input initiated in the 1950/1960s have altered grassland plant community composition, species diversity and functional trait composition using comprehensive datasets from five floodplain regions (plus one protected reference region) in northern Germany. Sites with available historical relevés and vegetation maps (1950/1960s, 1990s) were resampled in 2008 to facilitate the analysis of a period spanning four to five decades.Plant community composition changed tremendously in all study regions during the 50 year period, which was related to increasing Ellenberg indicator values for nutrient availability. Species richness at the plot-level fell by 30–50% over the period, and losses in functional diversity were equally large. A non-formal comparison with the results from the protected reference study region indicates that the changes may mostly be attributable to local nutrient input rather than to supra-regional climate change. Our results indicate a consistent trend towards much more species-poor communities dominated by mow-tolerant, N-demanding competitive grasses, whereas species with more ruderal strategies, species flowering early in the season and, in particular, insect-pollinated herbs have all decreased. The substantial loss of nectar-producing grassland herbs is likely to have negative effects on the abundance of pollinating insects, with consequences for the grassland animal communities. This highlights the growing need for adequate grassland management schemes with low N input to preserve high-nature-value grassland.     

Soil microbial communities and activities in sand dunes of subtropical coastal forests

To understand the soil microbial activities and community structures in different forests in a sand-dune ecosystem, we conducted a study of 2 topographic conditions, upland and lowland, under a Casuarina forest. As well, in the lowland site, we compared forest soil microbial properties under 3 coastal forests (Casuarina, Hibiscus and mixed stand). The soil microbial biomass did not significantly differ between the upland and lowland Casuarina forest sites. At the lowland site, the soil microbial biomass was higher in the Hibiscus than Casuarina forest soil. Cellulase, xylanase, phosphatase and urease activities did not show a consistent trend by topography or vegetation. Analysis of phospholipid fatty acids (PLFAs) of bacteria and actinomycetes revealed a significant difference in microbial community structure by both topography and vegetation. PLFA content was higher at upland than lowland sites in the Casuarina forest. At the lowland site, the level of PLFAs was higher in Hibiscus than Casuarina forest soil. In addition, we examined the ratios 16:1ω7t/16:1ω7c and, cy17:0/16:1ω7c as indicators of physiological stress; the soil in the Casuarina forest had the highest values, which suggests that the microbial community in the Casuarina forest soil is under physiological stress or starvation conditions. Comparison of soil microbial properties suggest that planting Hibiscus may help to enrich soil fertility and increase microbial activities in coastal sand-dune Casuarina forest.     

Seasonal dynamics of soil microbial biomass in coastal sand dune forest

Sand dunes are a typical landscape in the coast of western Taiwan, where Casuarina forests were established decades ago to stabilize sand dunes and protect the inland vegetation. Study of microbial biomass in such an ecosystem may give insights into the role of microbes in soil fertility and nutrient cycling. We established our study sites in two topographic units based on elevation and drainage types: upland and lowland. The study lasted for 2 years, and soil samples were collected every 3 months. Microbial biomass C (C_mic) and N (N_mic) were high in a shallow humic layer that rested on top of the soil (1222–1319 mg kg⁻¹ for C_mic and 245–276 mg kg⁻¹ for N_mic) and declined sharply to only one-tenth of the above values in the underlying surface soil (0–10 cm depth). Microbial biomass C_mic and N_mic in humic and surface soil were not significantly different between upland and lowland sites. In the upland soils, the mean C_mic was highest in autumn for both the humic and surface soil, and lowest in spring and summer for the humic layer and summer for the surface soil layer. In the lowland soils, the C_mic was highest in winter for both humic and surface soil, and lowest in spring and autumn for the humic layer and spring and summer for surface soil. Strong fluctuations of C_mic and N_mic were associated with the soil moisture prior to sampling, which appeared to control the size of microbial biomass in this environment. Temperature had little effect on the dynamics of soil microbial biomass in the sand dune forest ecosystem.     

Temporal changes of resource use,soil fertility and economic situation in upland Northwest Vietnam

Agricultural land in lowland Vietnam is scarce due to population growth. Hence, cultivation is increasingly practised on the steep upland slopes. Factors affecting resource use, soil fertility and household economics were studied in six villages of the Black Thai ethnic group in northwest Vietnam. Farmers were interviewed about their individual household situation. Yield development of major crops and cropping patterns in upland cultivation over the last 50 years were recorded in group discussions. In addition, soil fertility was analysed on different land‐use units. Formerly predominant upland rice changed to maize and cassava production at present. Decreasing soil fertility and a shift from subsistence to market‐oriented production, facilitated by new maize varieties and better access to markets are major causes. The Black Thai farmers economy has improved in recent years. The decline in soil fertility is concealed by higher maize yields from new varieties, and soil fertility conservation ranks low among farmers' priorities. The improved economy of the individual households might be of short duration if farmers cannot be sensitized to new resource management options. These have to be developed in line with farmers' priorities and the fragile environment of Vietnam's uplands. Copyright © 2002 John Wiley & Sons, Ltd.     

Declines in forage availability for bumblebees at a national scale

We assessed national scale changes in the forage plants of bumblebees in Britain, as a means of providing quantitative evidence for the likely principal cause of declines in bumblebee species. We quantified the relative value of native and long-established plant species as forage (nectar and pollen) resources for bumblebees by collating visitation data from 14 field sites across Britain. Twentieth Century changes in range and frequency of these forage plants were assessed using data from the New Atlas of the British and Irish Flora (1930-1969 to 1987-1999) and the Countryside Surveys of Britain (1978-1998). Forage plants declined in both large-scale range and local-scale frequency between the two survey periods. These changes were of greater magnitude than changes in other native plant species, reflecting serious reductions in quality of foraging habitats for bees as well as a general decline in insect-pollinated plants. Seventy-six percent of forage plants declined in frequency within 1-km squares, including those (e.g. Trifolium pratense) of particular value for threatened bumblebee species. We consider how our findings relate to other recorded changes in the British flora, how they may help to explain declines in bumblebees and how they could contribute to a conservation strategy.     

Nutrient and bulk density characteristics of soil profiles in six land use systems along topo-sequences in inland valley watersheds of Ashanti region,Ghana

The bulk density and nutrient distribution in soil profiles as affected by various land use systems were studied. Mean bulk densities of the various soil profiles, 0-20, 20-40, and 4060 cm in the selected five land use systems along the upland / lowland topo-sequences were, 1.26, 1.73, and 1.44 Mg m^-3 for the primary forest (PF) plot in the upland area, 1.13, 1.51, and 1.50 Mg m^-3 for the cacao farm (CP) plot, 1.16, 1.63, and 1.26 Mg m^-3 for the mixed cropping (MC) plot, 1.39, 1.61, and 1.50 Mg m-a for the fallow (Fallow) plot, all three land use systems being in the upland / fringe areas, and 1.46, 1.72, and 1.60 Mg m^-3 for the lowland traditional rice farming (TR) plot, respectively. The very high bulk density of the second layer, especially in the PF plot, may be related to the hardening of the iron / quartz stone layer due to prolonged dry conditions, which may affect plant growth and hydrological cycles in the benchmark inland valley watersheds. The TC contents of the topsoil samples were 43, 32, 24, 26, 18, and 15 g kgm^-1 for the PF, CP, Fallow, MC, TR, and sawah (Sawah) plots, respectively. The C / N ratios of the topsoil samples were 10, 10, 9.8, 9.1, 8.8, and 8.8 for the CP, Fallow, MC, Sawah, TR, and PF plots, respectively, displaying a higher natural fertility, especially for the N supply in the PF plot in the upland area. The available phosphorus levels were low even for the topsoil samples, 1.8 to 3.4 mg kg^-1 for the upland soils while the lowland TR and Sawah plots recorded values of 4.4 and 4.9 mg kg^-1, respectively. The contents of exchangeable K, 0.1-0.4 cmole kg^-1, of the topsoil samples were in the range of those of normal inland valley soils in West Africa. In contrast to the content of available P, although the MC plot showed a depletion, the PF, Fallow, and CP plots showed a replenishment of available K through biological nutrient cycling. The levels of exchangeable Ca and Mg as well as eCEC, were also relatively high compared to those of mean inland valley soils in West Africa. The major component of eCEC was Ex. Ca. The levels of Ex. Ca in the topsoil samples were 11.1, 9.1, 7.8, 4.7, 5.1, and 3.9 cmol_c kg^-1 for the PF, CP, Fallow, MC, TR, and Sawah plots, respectively. The distinctive feature of Ex. Mg was its large distribution in the upper soil profiles in the CP plot, indicating that in the cacao farms, Ex. Mg was enriched, probably due to the high level of Mg in the leaf litter. The lowland soils, normally, should have been enriched in exchangeable bases such as Ca, K, and Mg, leading to a higher eCEC value and higher general fertility through the process of geological fertilization, Le., nutrient flows from upland to lowland areas, as in the case of lowland sawah in monsoon Asia. At the benchmark sites, however, the effects of the geological fertilization process were not evident. This is one of the most important characteristics of West African inland valley watersheds.     

Distribution of endangered bryophytes in Austrian agricultural landscapes

In Austrian agricultural landscapes, 1936 sampling plots within 72 study sites selected by a random procedure were investigated with regard to their bryophyte vegetation. Out of a total of 506 species, 135 endangered species were recorded. Thirty-eight percent of all populations of endangered species showed sporophytes and 15% produced vegetative reproduction units. There is a significantly higher number of endangered species growing in upland landscapes dominated by moderately intensive cattle farming than in lowland landscapes with a wide range of mainly intensive farming styles. The percentage of species that are endangered is higher in intensively than in moderately used areas. The sampling plots differed strongly in respect to their number of endangered species. Very important habitats for endangered bryophytes are less intensively used vineyards, moderately and less intensively used meadows (including fens), field margins and fallow lands. There is a significant negative correlation between land-use intensity as defined by the hemerobic state and the number of endangered species. The distribution of endangered species according to land-use and habitat quality is discussed.     

A comparison of the ecological quality of land between an English agri-environment scheme and the countryside as a whole

A survey of 451 Countryside Stewardship Scheme (CSS) agreements was carried out across England in 1998-1999 to characterise the ecological quality of the land. The land within the agreements was mapped using the UK Biodiversity Action Plan Broad and Priority Habitats and the vegetation of the agreements was sampled using random quadrats. By far the most widespread Broad Habitat was Improved Grassland, accounting for around 50% of all agreement land. Of this, the majority was semi-improved. Priority Habitats accounted for 15% of all agreement land (equivalent to around 18,500 ha). In addition to the 15%, there was also land within habitat mosaics containing one or more Priority Habitat. The analysis of vegetation revealed that 53% of all randomly-placed quadrats were categorised as Infertile Grassland and 24% as Fertile Grassland. Survey data were compared with results from the Countryside Survey 2000, a national assessment of vegetation undertaken in 1998. In the lowland areas of England, CSS land had a much higher proportion of grassland habitats and was much more likely to be typical of low fertility situations than the countryside as a whole. In the marginal uplands and uplands, CSS agreement land contained a greater proportion of grassland, but with a reduced proportion of important upland Broad Habitats, such as Dwarf Shrub Heath and Bog, although these do tend to be found more in the Environmentally Sensitive Areas. The differences between the CSS and the countryside as a whole clearly reflect the priorities of the CSS, especially the high proportion of grassland. The CSS has targeted Broad and Priority Habitats and in this respect has been successful.     

The response of plant and insect assemblages to the loss of Calluna vulgaris from upland vegetation

Across large areas of upland Britain Molinia caerulea and Nardus stricta are replacing Calluna vulgaris as the dominant plant species of the vegetation assemblage. Associated changes in the composition of the whole plant assemblage and a phytophagous insect group, the Hemiptera, were investigated. Vegetation and hemipteran assemblages were sampled at six moorland sites in northern England and Scotland. Sampling at each site was carried out in Calluna vulgaris-dominated areas and grass-dominated areas that had previously been dominated by C. vulgaris. Vegetation assemblages of heath and grass sites differed significantly even when species by which sites were selected for sampling (C. vulgaris, M. caerulea and N. stricta) were removed from the analysis with the highest species richness in dry grassland sites. Hemipteran assemblages differed significantly between heath and grass sites with greater species richness also being in grass sites. Plant species composition was the most important explanatory variable of hemipteran assemblages with temperature, latitude, soil loss on ignition and vegetation height also explaining a significant proportion of the variation. Overall a range of vegetation composition and structural variables explained 40.8% of variation in the Hemiptera species data with ranges of soil and biogeographic variables explaining an additional 8.7%.This research demonstrates that the replacement of one dominant plant species by another is associated with a change in other aspects of moorland biodiversity. In particular the loss of C. vulgaris actually leads to an increase in the species richness of Hemiptera and plants although the number of specialist species declines.     

Land use dynamics and nutrient characteristics of soils and plants along topo-sequences in inland valley watersheds of Ashanti region,Ghana

Surveys on land use dynamics were conducted over a 3-year period along various toposequences in benchmark inland valley watersheds of the Ashanti region, Ghana. Six typical land use systems were selected for more detailed studies, Le., primary forest (PF), cacao farm (CP), fallow (Fallow), mixed cropping (MC), and lowland rice-based systems including both traditional rice (TR) and sawah{ft1} (paddy)-based rice farming (Sawah). Topsoil samples (0-20 cm) and samples of leaves and bark of various plants were collected from these land use systems for nutrient characterization using laboratory analyses. The remaining primary and secondary forests cover only a patchy area, accounting for less than 20%, in forest reserves and surrounding areas. Cacao farms were developed both in the upland areas, middle slopes, and lowland areas, which occupied about 20% of the watershed. Lowland rice farming is estimated to account for about 10% of the watershed. Oil palm cultivation is also common in the lowland areas. The remaining land use systems were mostly fallow and mixed cropping of maize, cocoyam, cassava, and plantain. Plant leaves of various species in the lowland traditional rice area showed higher concentrations of phosphorus and potassium but lower calcium and strontium concentrations than those of the leaves in the upland surveyed plots, especially, the forest area. Nitrogen, sulfur, magnesium, and the other mineral elements, however, did not show any clear differences among the six land use systems. Bark samples tended to exhibit lower concentrations of nitrogen, phosphorus, sulfur, magnesium, sodium, silicon, aluminum, iron, manganese, and copper but higher concentrations of calcium and strontium. Cacao leaves showed silicon-accumulator characteristics and the magnesium concentration was high too. Cacao bark contained potassium and zinc in appreciable amounts in compared to the leaves. Topsoil samples of the primary forest and cacao farms in the upland areas showed higher levels of TC, TN, exchangeable Ca and Mg, and eCEC while the levels of available P showed a rather reverse trend compared to the lowland traditional and sawah rice plots. Topsoil samples of the fallow and mixed cropping plots at upland and fringe sites showed intermediate levels. The pH at the mixed cropping site was the lowest. These general fertility trends along upland and lowland topo-sequences were different from those of monsoon Asia and Japan. With the implementation of the sawah rice-based farming system, the inland valleys could contribute to the enhancement of sustainable food production in the country.     

Plant uptake of radionuclides

Abstract. The factors influencing uptake of radionuclides from soils into vegetation are discussed with reference to soil type, radionuclide, plant species and organ, and time since initial contamination. Gaps in knowledge are identified, particularly as highlighted by the unexpected behaviour of radiocaesium in many upland areas of Britain, following deposition after the Chernobyl accident. The importance of resuspended soil for contamination of aerial plant parts is also considered in relation to radionuclide type, vegetation height, and meteorological conditions.
The development of an international database by the International Union of Radioecologists for soil to crop transfer factors of radionuclides derived from European experiments is briefly described. This database is now being used for statistical analyses aimed at quantifying the importance of environmental and biological factors in influencing uptake of radionuclides from the soil.     

Response of common bean,upland rice,corn, wheat,and soybean to soil fertility of an Oxisol

Plant nutrient deficiencies are the main yield‐limiting factors in highly weathered acid soils around the world. Five greenhouse experiments were conducted on an Oxisol to identify nutrient deficiencies in common bean, upland rice, corn, wheat, and soybean. The treatments consisted of 13 fertility levels including an adequate level and remaining without application of one of the essential plant macro‐ or micronutrients. Dry matter yield of tops of all the crop species was affected by fertility treatments; however, significant effects of treatments were obtained in the case of common bean, upland rice, and corn. Based on tops dry weight under different treatments compared to adequate fertility level (AFL), the most yield‐limiting nutrients were in the order of phosphorus (P) > calcium (Ca) > magnesium (Mg) > boron (B) > zinc (Zn) for common bean, P > molybdenum (Mo) for upland rice, and P for corn. For the wheat crop, there was substantial decrease in tops dry weight in the absence of Ca, P, and potassium (K) nutrients. In the case of soybean, substantial tops dry weight reduction was due to deficiency in the order of P >Ca>Zn.     

桂西北环境移民安置区柑橘园土壤环境动态研究

对桂西北环境移民安置区柑橘园开垦后土壤环境动态变化的研究结果表明,该安置区土壤肥力总体变化趋势呈先降后升,土壤pH值微弱降低,土壤酸性强度有所增强,土壤有机质含量先降后升,全N含量呈下降趋势,而水解氮和全P、速效钾及速效磷含量均呈上升趋势,全K含量先升后降,并分析了土壤各养分演变成因。     

丘陵红壤耕作利用过程中土壤肥力的演变和预测

通过区域尺度上两个时段的定位采样 ,结合田块尺度上的长期试验 ,研究了耕作利用变化对我国中亚热带低丘红壤区土壤肥力演变的影响。分析了土壤肥力演变的驱动力 ,建立了土壤养分变化与养分平衡间的相关预测模型。对比分析表明 ,丘陵红壤肥力的变化与养分平衡量的变化趋势一致。在保持荒地和水田利用方式时 ,土壤有机质含量显著降低 ;旱地系统中速效磷和速效钾含量增加 ,但在不施肥的针阔混交林中却下降 ;荒地开垦为水田后 ,土壤肥力有增加趋势。旱坡地红壤全氮和速效钾的变化量与氮、钾的平衡量的显著相关 ,而土壤速效磷与磷的平衡量间相关不显著 ,其原因是没有考虑磷的固定和矿化。     

Bracken effects on inorganic nitrogen leaching from an upland podzol

Leaching of inorganic N species to stream waters from upland areas of the UK is increasing, reflecting the increases in atmospheric deposition of nitrogen species due to increased levels of vehicular emissions. Bracken cover in UK uplands is also increasing overall ( Taylor, 1986 ), and the architectural nature of bracken has been shown to both increase deposition of atmospheric constituents to soils and change their chemical and physical nature. We have tested the nutrient status of upland podzols from the Lake District, Cumbria, UK, from under both moorland grass and bracken. The results show reduced levels of base cations and nitrate throughout the profile and decreases in the organic matter content of surface horizons as a consequence of bracken encroachment. We also report increased ammonium concentrations in lower soil horizons under bracken, possibly leading to increased leaching to stream waters. These results suggest either increased leaching of soil nutrients due to bracken encroachment or increased storage of nutrients within the bracken rhizome system. Results also suggest changes in either microbial activity or the microbial community of podzols, possibly due to the allelopathic nature of bracken. This may have caused changes in the soil nutrient dynamics, possibly accounting for some of the changes seen. We hypothesize that increased bracken cover within the British uplands has the potential to increase leaching of inorganic nitrogen to upland streams.     

Improving soil organic carbon pools through inclusion of summer mungbean in cereal-cereal cropping systems in Indo-Gangetic plain

Long-term effect of mungbean inclusion in lowland rice-wheat and upland maize-wheat systems on soil carbon (C) pools, particulate organic C (POC), and C-stabilization was envisaged in organic, inorganic and without nutrient management practices. In both lowland and upland systems, mungbean inclusion increased very-labile C (Cfrac₁) and labile C (Cfrac₂) in surface soil (0–0.2 m). Mungbean inclusion in cereal-cereal cropping systems improved POC, being higher in lowland (107.4%). Lowland rice-based system had higher passive C-pool (11.1 Mg C ha^?1) over upland maize-based system (6.6 Mg C ha^?1) indicating that rice ecology facilitates the stabilization of passive C-pool, which has longer persistence in soil. Organic nutrient management (farmyard manure + full crop residue + biofertilizers) increased Cfrac₁ and carbon management index (CMI) over inorganic treatment. In surface soil, higher CMI values were evident in mungbean included cropping systems in both lowland and upland conditions. Mungbean inclusion increased grain yield of cereal crops, and yield improvement followed the order of maize (23.7–31.3%) > rice (16.9–27.0%) > wheat (lowland 7.0–10.7%; upland 5.4–16.6%). Thus, the inclusion of summer mungbean in cereal-cereal cropping systems could be a long-term strategy to enrich soil organic C and to ensure sustainability of cereal-cereal cropping systems.     

红壤旱地的肥力现状及施肥和利用方式的影响

红壤旱地是我国南方亚热带地区十分重要的土壤类型,其酸性较强,pH值一般在6.0以下、交换性酸含量在4.4 cmol(+)kg-1以上;且土壤有机质含量较低,普通旱地含量通常在20g kg-1以下;养分含量不高,全氮和全磷含量通常在1.0g kg-1左右、速效磷含量一般在10mg kg-1甚至5mg kg-1以下、速效钾含量大多低于100mg kg-1。施肥是影响红壤旱地肥力的重要因素之一,有机无机肥配合施用有利于红壤肥力的提高;而利用方式对红壤旱地肥力的影响主要通过施肥和作物对养分的吸收利用。根据红壤旱地的肥力现状及该地区农业发展的需要,提出了应加强养分平衡与流失规律、土壤性质调控与改良、高效利用与管理模式以及长期定位监测等方面的研究。     

粉煤灰堆场植被恢复过程的养分效应及重金属变化特征

对黑龙江省鸡西滴道矸石电厂粉煤灰堆场自然植被恢复方式与人工恢复方式中粉煤灰基质养分、重金属含量变化特征进行研究,分析不同恢复方式对基质养分、重金属污染物状况的影响规律。结果表明：1）粉煤灰基质中养分含量极不均衡,有机质、全氮、速效氮、速效磷等营养元素严重缺乏,速效钾含量较丰富;2）粉煤灰在自然堆放过程中存在养分流失现象,全效性养分的流失程度高于速效性养分的流失程度;3）人工植被恢复过程极显著地改善了表层基质的养分状况,有机质含量增加459.28%,全氮增加238.46%,全磷增加131.4%,速效性N、P、K含量分别提高30.17%、56.29%、22.58%;4）粉煤灰堆场主要超标重金属为Hg,客土沙棘恢复方式有效降低了粉煤灰基质重金属含量,Hg、Cu、Cr含量相对自然恢复草地分别降低了66.93%6、8.82%和16.09%。     

Invasion success of exotic plants in natural ecosystems: the role of disturbance, plant attributes and freedom from herbivores

Invasion of natural ecosystems by exotic species is a major threat to biodiversity globally. We assessed two alternative (but not exclusive) hypotheses to explain the success of exotic species in urban bushland on low fertility sandstone-derived soils in Sydney, Australia. These were that success of exotic species is promoted by: (1) plant attributes in particular disturbance types; and (2) freedom from herbivores. We tested these at sites subject to different types of disturbance: nutrient and water enrichment (below stormwater outlets), nutrient enrichment (riparian zones of creeks with an urban catchment) and physical disturbance (tracks), and control sites. At each site we estimated percentage cover of all species and surveyed leaves for damage by herbivores. Species were classified as native, non-invasive exotic or invasive exotic. We found that sites without any disturbance did not support exotic plants. Physically disturbed sites on low fertility soils supported only one exotic species, suggesting that nutrient enrichment is a critical prerequisite for exotic species invasion on low fertility soils. Exotic species cover was highest and native species richness most reduced in areas of highest nutrient enrichment. Both invasive exotic and non-invasive exotic species had significantly lower levels of leaf herbivory than native species, implying that release from pests alone cannot account for the success of invasive species. Specific leaf area of invasive exotic species was consistently higher than specific leaf area of non-invasive exotic and native species, regardless of disturbance type. In physically disturbed sites of higher soil fertility, exotic species were small herbs and grasses of long flowering duration and with small unassisted or wind-dispersed seeds. In sites subject to nutrient-enrichment, exotic species were more likely to be climbers, able to propagate vegetatively, and with seeds dispersed by vertebrates. Thus different plant attributes contribute to exotic species success under different disturbance types. The clearest consistent difference we found between invasive exotic and non-invasive exotic species was in specific leaf area, suggesting that large specific leaf area facilitates invasiveness.