江苏宜兴森林自然保护区种子植物区系特点及植被性质

对江苏宜兴森林自然保护区及周边地区的种子植物区系成分进行统计分析,归为４大类１５个分布类型。属的成分以温带比例最高（６１％）,东部成分亦较明显（２５％）,中西部成分极少,几无本地特有成分,属较典型的华东植物区系地区。对该地区现存植物进行计算分析,结合栽培植物及古植被资料,得出以青冈〔Ｃｙｃｌｏｂａｌａｎｏｐｓｉｓｇｌａｕｃａ（Ｔｈｕｎｂ．）Ｏｅｒｓｔ．〕、石栎〔Ｌｉｔｈｏｃａｒｐａｇｌａｂｅｒ（Ｔｈｕｎｂ．）Ｎａｋａｉ〕等为建群种的中亚热带常绿阔叶林是本地区的地带性植被。自然保护区建立（１９８１）以后植被恢复明显,许多样地已接近自然植被。     

A critique of and recommendations for a subsistence fishery, Lake St Lucia, South Africa

The fish resources of Lake St Lucia, the largest estuary on the eastcoast of Africa, present resource managers of the Natal Parks Board with acommon property resource (CPR) problem. Problems associated with illegal gillnetting by local people from three tribal areas, prompted the introduction of asystem of legal, subsistence netting. This paper reviews the legal fisheries inthese three areas from 1995 to 1997, and examines existing organizationalarrangements, suggesting reasons why the three fisheries show differences infunctioning. By employing concepts from CPRs theory, elements of anorganizational design for fisheries management involving local users and theconservation organization staff are proposed.     

Saldanha Bay,South Africa: recovery of Gracilaria verrucosa (Gracilariales,Rhodophyta)

Since World War II the greater Saldanha Bay lagoon system, South Africa, has been an important Gracilaria producer. Two agar factories, built in the 1960's, used Gracilaria from Saldanha Bay as their raw material. In the early 1970's the industry was destroyed as a result of dredging and marine construction operations to establish a harbor in the bay for loading ore. These environmental changes destroyed stocks and prevented the previously significant beachings of the seaweed from occurring. After a few years of no or very low commercial production, the resource slowly started to recover. The size of Gracilaria drifts increased over the following eight years to approximately one-third of the original output. This trend seems to continue. Although the stocks and resultant drifts are unlikely to recover fully to their original quantity, current production is already sufficient to ensure re-establishment of a seaweed industry in Saldanha Bay. This could have considerable socio-economic impact on the area.     

广州从化温泉自然保护区植被和植物群落的特征

对从化温泉自然保护区进行了详细植被和群落学调查。该保护区包括天然和人工群落一类型两大类。其中天然群落一景观类型包括常绿叶林、常绍针叶林、常绿针阔叶混交林以及撩荒地。人工群落－－景观类型包括村落、农田、果园以及水库。利用Ｃｌｅｍｅｎｔ多度启示法调查确定了天然植物中群落的优势和建群种。该保护区群落的优势种为藜蒴Ｃａｓｔａｎｏｐｓｉｓ ｆｉｓｓａ、荷木Ｓｃｈｉｍａ ｓｕｐｅｒｂａ、黄樟Ｃｉｎｎａｍｏｍｕ     

Seasonal variation in antimicrobial and phytochemical properties of frequently used medicinal bulbous plants from South Africa

The growing popularity of traditional medicine and the unrestricted collection of medicinal plants from the wild have put many of the slow growing bulbous plant species at the risk of over-exploitation and extinction in South Africa. This study was aimed at comparing the phytochemical composition and biological (antibacterial and anticandidal) activities of bulb and leaf extracts of Tulbaghia violacea, Hypoxis hemerocallidea, Drimia robusta and Merwilla plumbea between spring, summer, autumn and winter seasons, with the view of promoting the use of leaves, as a conservation strategy. Antibacterial and anticandidal activities of petroleum ether (PE), dichloromethane (DCM), 80% ethanol and water extracts of bulbs and leaves were tested against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae bacteria and the fungus Candida albicans using the microdilution bioassay. Spectrophotometric methods were used to evaluate saponin and phenolic compositions for the four seasons. Leaf and bulb extracts exhibited comparable anticandidal activity (MIC < 1 mg/ml) in all the plant species in all seasons. Only ethanol and water extracts of H. hemerocallidea corms (autumn and winter) showed correspondingly good fungicidal activity amongst the bulbs tested. Antibacterial activity was fairly comparable between bulbs and leaves with at least one extract of each plant species showing some good MIC values in most of the seasons. The best antimicrobial activities were recorded in winter and autumn seasons, with MIC values as low as 0.2 mg/ml in the DCM bulb extracts of T. violacea (winter) against K. pneumoniae and S. aureus. The amounts of total phenolic compounds in all plant samples were generally higher in spring compared to the other seasons. Condensed tannin, gallotannin and flavonoid levels, depending on the sample, were either higher in spring or winter except for H. hemerocallidea (corm) which had higher gallotannin levels in autumn. Total saponin levels were higher in winter in all plant samples. Although variation was observed in the phytochemical concentrations between the bulbs and leaves of each plant species, their antimicrobial activities were fairly comparable. Leaves may be used as substitutes for bulbs in the treatment of bacterial and fungal ailments.     

Yeast alpha glucosidase inhibitory and antioxidant activities of six medicinal plants collected in Phalaborwa,South Africa

Recent decades have experienced a sharp increase in the incidence and prevalence of diabetes mellitus. One antidiabetic therapeutic approach is to reduce gastrointestinal glucose production and absorption through the inhibition of carbohydrate-digesting enzymes such as α-amylase and α-glucosidase and α-amylase. The aim of the current study was to screen six medicinal plant species, with alleged antidiabetic properties for α-glucosidase inhibitory activities. Powdered plant materials were extracted with acetone, and tested for ability to inhibit baker's yeast α-glucosidase and α-amylase activities. The largest mass (440 mg from 10 g) of the extract was obtained from Cassia abbreviata, while both Senna italica and Mormordica balsamina yielded the lowest mass of the extracts. Extracts of stem bark of C. abbreviata inhibited baker's yeast α-glucosidase activity with an IC₅₀ of 0.6 mg/ml. This plant species had activity at low concentrations, with 1.0 mg/ml and above resulting in inhibition of over 70%. The other five plant extracts investigated had IC₅₀ values of between 1.8 and 3.0 mg/ml. Senna italica only managed to inhibit the activity of enzyme-glucosidase at high concentrations with an IC₅₀ value of 1.8 mg/ml, while Tinospora fragosa extracts resulted in about 55% inhibition of the activity of the enzyme at a concentration of 3.5 mg/ml, with an estimated IC₅₀ value of 2.8 mg/ml. The bark extract of C. abbreviata was the most active inhibitor of the enzyme, based on the IC₅₀ values (0.6 mg/ml). The bark extract of C. abbreviata contains non-competitive inhibitor(s) of α-glucosidase, reducing V_max value of this enzyme from 5 mM·s^–1 to 1.67 mM·s^–1, while K_m remained unchanged at 1.43 mM for para-nitrophenyl glucopyranoside. Antioxidant activity of the extracts was also investigated. The C. abbreviata extract was more active as an antioxidant than the positive control, trolox. The extracts did not inhibit alphaamylase activity more than about 20% at the highest concentration tested.     

The relationship between local and regional diversity of indigenous forest fauna in KwaZulu-Natal Province, South Africa

The relationship between local and regional diversity was tested by regressing local community richness against regional species diversity for three taxa, birds, butterflies and mammals, in subtropical forest. The quadratic model best fits the relationship between local and regional diversity for birds. Local bird species richness is theoretically independent of the size of the regional pool of species and may represent saturated communities. A linear model best describes the relationship for mammals and butterflies. For mammals, the slope is shallow (0.264) and regional richness overestimates local species richness, suggesting communities are undersaturated. Extinction filtering may explain this pattern. Past climatic changes have filtered out many mammalian species, these changes have been too recent for autochthanous speciation, and the relatively low vagility of mammals has prevented extensive recolonisation. Differences in the nature of the diversity relationship between taxa are as much due to independent evolutionary histories as to differences in vagility and colonising potential. A pervasive role is suggested for regional biogeographic processes in the development of faunal assemblage structure. Large-scale processes are not considered in current conservation plans. We encourage the shift of conservation emphasis from local ecological processes and species interactions, to whole communities and consideration of regional processes.     

Chemical quality of the burnt and non-burnt grass layer in the Nylsvlei Nature Reserve,South Africa

The forage quality of the herbaceous layer in burnt and non-burnt plant communities was determined seasonally to serve as a baseline for managing the food supply. The near-infrared reflectance spectroscopy method and wet chemical analyses were applied to analyse the grass samples. Differences in forage quality were found between plant communities. The Sporobolus ioclados–Acacia tortilis Savanna had the highest forage quality throughout the year. Plant communities on the lithosols had a low forage quality. The highest total calcium and total phosphorus concentrations were found in the Eragrostis pallens–Burkea africana Savanna, total potassium in the plant communities on the lithosols, and total sodium in the Sporobolus ioclados–Acacia tortilis Savanna and floodplain. The most optimum Ca:P ratio was found in the Eragrostis pallens–Burkea africana Savanna when burnt and non-burnt. In non-burnt areas the highest K:Na ratio was found in the Sporobolus ioclados–Acacia tortilis Savanna. Burning increased the forage quality in some plant communities. In general, only percentage in vitro organic matter digestibility differed significantly between burnt and non-burnt plant communities. The forage quality did not increase significantly in plant communities on lithosols and on vertisols. Mineral ratios did not differ between newly burnt plant communities. A low protein and mineral content in the winter forage should be countered with supplementary feeding or burning of grass to improve the condition of animals.     

Spatial and trophic partitioning in cryptic fish communities of shallow subtidal reefs in False Bay, South Africa

Thirty-nine species of cryptic fishes belonging to 16 families were captured on shallow reefs (0-20 m) in False Bay, South Africa using the ichthyocide rotenone. Five samples were collected in each of four depth zones (0-5, 6-10, 11-15 and 16-20 m). The area from which fish were collected in each sample was measured to give an estimate of density. The overall density of cryptic fishes in the area was 3.41 fish m^-2, with the families Congrogadidae and Clinidae being numerically dominant, representing 27.9% and 22.3% of the total sample respectively. The Clinidae were by far the most diverse group, being represented by 17 species, while no other family was represented by more than three species. Multivariate analysis of numerical density revealed that partitioning of spatial resources did occur, with the shallowest samples (0-5 m) forming a group discrete from the deeper samples (6-20 m). Further analysis indicated that the amount of algal cover present was the most important factor influencing community structure, although the abundance of algae is in turn related to depth. The shallowest samples were dominated by members of the families Clinidae, Gobiesocidae and Bythitidae, while the Cheilodactylidae, Tripterygiidae and Ariidae were more important components of deeper water communities (6–20 m). Analysis of percentage volume of prey items in the diets of 21 species revealed that only two species shared diets that were more than 50% similar, and that partitioning of trophic resources was considerable. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ecological integrity assessment of the fish assemblages of the Matigulu/Nyoni and Umvoti estuaries,KwaZulu-Natal,South Africa

The estuarine fish community index (EFCI) and an estuarine fish guild assessment (EFGA) were used in 2004 and 2008 to determine the ecological state and effects of selected ecosystem variables on the Umvoti and Matigulu/Nyoni estuaries. The EFCI indicated that the Matigulu/Nyoni Estuary was in a moderate state and that the Umvoti Estuary was in a poor to very poor state. The EFGA revealed a clear spatial differentiation, based on the estuaries’ fish community structures, that was being driven primarily by the freshwater-dominated state of the Umvoti Estuary and the poor water quality of the Umvoti Estuary. The analysis of estuarine fish assemblage characteristics was shown to contribute towards the management and conservation of these systems.     

Comparative molecular phylogeography of two Xenopus species, X. gilli and X. laevis, in the south-western Cape Province, South Africa

Xenopus gilli is a vulnerable anuran with a patchy distribution along the south-western coast of the Cape Province, South Africa. This species is sympatric with Xenopus laevis laevis , a widespread relative found over much of southern Africa. We examined the molecular phylogeography and population structure of the contact zone between these species to obtain information about historical biogeography and conservation management of this region. Analyses of the distribution, frequency, and cladistic and phenetic relationships among mitochondrial DNA haplotypes indicate that population subdivision is present in both taxa but that long-term isolation of sets of populations has occurred in X. gilli only. Haplotype and nucleotide diversity are also considerably higher within and among X. gilli ponds than X. l. laevis ponds in this region. We attribute the genetic segregation of X. gilli populations to ancient habitat fragmentation by ocean transgression into X. gilli habitat and to continued habitat alteration by human activity. The lower level of genetic diversity in X. l. laevis in this region is likely a result of a recent arrival of this taxon to the south-western Cape region relative to X. gilli . Population structure in X. l. laevis may be a result of isolation by distance. Clear evidence exists for at least two management units within X. gilli and strongly supports the establishment of protective measures east of False Bay in order to conserve a substantial portion of this species' extant genetic diversity.     

Arthropod Diversity in Lama Forest Reserve (South Benin), a Mosaic of Natural, Degraded and Plantation Forests

Arthropod assemblages were examined in Lama forest reserve, a protected area situated in the Dahomey gap, southern Benin, composed of plantations, degraded forest and remnants of natural forest. The objectives were to compare assemblages in relation to forest type and use, to elucidate the value of forest plantations for biodiversity conservation and to identify indicator species for specific forest habitats. Arthropods were collected over an 11-month period, using standardized sets of traps (pitfall, emergence, Malaise and flight intercept traps). Nine different habitats were studied, including natural and degraded forest, forest plantations (Tectona grandis and Senna siamea) of different age, and isolated forest fragments. Our analysis focused on detritivorous and xylophagous arthropods but also included ground beetles and heteropterans, totalling 393 species. We found no differences in species richness among natural and degraded forest habitats in the centre of the reserve (Noyau central). Outside of the Noyau central, species richness was highest in old teak plantations and isolated forest fragments and lowest in young teak and fuelwood plantations. Detrended correspondence analysis (DCA) separated three main groups: (1) natural forest, (2) degraded forest and young plantations, and (3) old plantations and isolated forest fragments. Multiple regression of DCA scores of the first two axes on environmental variables identified one natural and three disturbance-related predictors of arthropod assemblages in Lama forest: soil type (texture), canopy height, naturalness (proportion of Guineo-Congolian plant species) and understorey vegetation cover. We identified 15 indicator species for six different forest habitats. The highest numbers were found in abandoned settlements and old teak plantations. β-diversity was similar among the three DCA ordination groups (degraded forest excluded). Values for β-diversity were relatively high, suggesting that all major forest habitats contribute significantly to regional species pools and should therefore be protected. To enhance arthropod diversity, we propose that management practices in Lama forest should aim to encourage the development of species-rich understorey vegetation of the Guineo-Congolian phytogeographical region.     

Ecological and anatomical characterization of some Pinus patula ectomycorrhizas from Mpumalanga, South Africa

 Ectomycorrhizal (ECM) fungi are an important component of the Pinus patula Schlechdt. et Cham. forest ecosystem in Mpumalanga, South Africa. ECM roots are intimately associated with accumulated litter on the forest floor and four ECM isolates where examined to determine whether they provide plant access to inorganic and organic sources of nitrogen (N) and inorganic, complexed inorganic and organic sources of phosphorus (P). In in vitro studies, all isolates were found to utilize most of the organic N compounds and organic or complexed inorganic P compounds supplied. Thus, ECM fungi could play a significant role in providing N and P to P. patula, especially from sources to which the host plant would not normally have access. Temperature sensitivities and pH optima of the four isolates differed. Of the ECM isolates WITS 01 and WITS 06 were collected from a high-litter site; WITS 01 mycorrhizas, identified as Scleroderma citrinum, were white, smooth and dichotomously branched with smooth, pale yellow, differentiated rhizomorphs. The mantle was plectenchymatous with outer and inner layers showing ring-like arrangements of hyphal bundles. The Hartig net had a palmetti shape. The WITS 02 (not identified) mycorrhizas were brown with lighter coloured root tips, with simple to dichotomous branching, smooth with no distinct mantle and sparse hyphae occurred on the root surface. The Hartig net was palmetti type with lobed haustoria. The results are discussed in relation to ECM distribution and function in nutrient cycling. Accepted: 7 January 1999     

Species turnover, community boundaries and biogeographical composition of dung beetle assemblages across an altitudinal gradient in South Africa

Aim To identify biogeographical boundaries which are obscured by faunal overlap and habitat modification. Location KwaZulu-Natal in south-east, South Africa beyond the southern tip of the Moçambique Coastal Plain. Methods Species abundance data for dung beetles (Scarabaeidae: Scarabaeinae) were collected at six levels from the coastal escarpment (30°16′S – 500 m) to the top of the nearby Drakensberg (29°35′S – 2850 m). Cross-altitudinal boundaries were identified using clustering techniques, beta-diversity indices, and range edge analysis. Biogeographical data for the species were drawn from an extensive reference collection and used to classify the biogeographical affinities of the assemblages. Results Three discrete communities are defined (<10% similarity) from species abundance distributions. These communities occur in coastal forest (500 m), coastal to highveld grassland (500–1500 m), and montane grassland (1900–2850 m). Two of these communities are biogeographically homogeneous comprising >89% east coast endemics (coastal forest) or >84% South African montane endemics (montane grassland) in terms of abundance. The third community in coastal to highveld grassland is biogeographically more heterogeneous. Predominant biota of this community comprise both South African highveld endemics and elements with distributions extending into the tropics. At highveld levels (1500 m), there are proportionately more highveld endemics whereas at lowland levels (500 m), there are proportionately more tropical elements. At 1000 m, there was a change in the balance between these two groups across an anthropogenic gradient due to a decline in the proportion of endemics in favour of temperate/tropical generalists. This gradient from a natural grassland fragment to improved pastures of Kikuyu grass also parallels a decline in species richness and abundance. Species turnover analyses showed three different cross-altitudinal patterns. Range-edge analysis showed a trimodal pattern of species turnover (peaks in forest and the Drakensberg foothills as in the community analysis but also at 1000 m). Five beta-diversity indices showed either a bimodal pattern of turnover (forest/grassland and foothills/middle Drakensberg slopes) or a trimodal turnover pattern (forest/grassland, highveld/Drakensberg foothills, Drakensberg peaks). Main conclusions Clear altitudinal zonation is revealed by community and biogeographical analysis but one natural biogeographical boundary may be obscured by the process of habitat modification. This boundary at 1000 m is revealed by range-edge analysis and is supported by findings for plant communities. Beta-diversity, species turnover patterns diverged slightly from those suggested by the community and range-edge analyses.     

海南岛霸王岭热带山地常绿林和热带山顶矮林群落特征

热带山地常绿林和热带山顶矮林均属于热带云雾林.为了揭示其群落结构和物种多样性特征,在海南岛霸王岭热带山地常绿林和热带山顶矮林分别设置8个和10个2,500 m2样方,调查所有DBH≥1cm的乔木、灌木和藤本植株.结果显示:(1)热带山地常绿林幼树(1cm≤DBH＜5 cm)和小树(5cm≤DBH＜ 10 cm)的平均密...     

Antiglycation,comparative antioxidant potential,phenolic content and yield variation of essential oils from 19 exotic and endemic medicinal plants

The antioxidant potential, antiglycation, and total phenolic content of essential oils (EOs) extracted from 19 medicinal plants were assessed. The variation in yield of the EOs with respect to altitude and season was also studied. The antioxidant potential of Pimenta dioica (L.) Merr., Psiadia terebinthina A.J. Scott, Laurus nobilis L., Piper betle L., and Citrus hystrix DC. showed IC₅₀ values less/equivalent to the positive controls. Weak correlations were observed between the 1,1-diphenyl-2-picryl hydrazyl (DPPH) and xanthine oxidase (XO) assays as well as between the DPPH and nitric oxide radical scavenging (NO) assay and between the XO and 2,2 azinobis (3-ethylbenzothiazoline-6 sulphonic acid (ABTS) assay. Cupressus macrocarpa Hartw., L. nobilis, Cinnamomum zeylanicum Nees, and Psidium guajava L. successfully inhibited in vitro glycated end-products (IC₅₀: 451.53 ± 3.00, 387.04 ± 1.53, 348.59 ± 3.34 and 401.48 ± 2.86 µg/mL respectively) compared to aminoguanidine (IC₅₀: 546.69 ± 3.57 µg/mL). Some of the EOs had a high content of phenolic compounds. EOs such as P. dioica, P. terebinthina, L. nobilis, P. guajava, and C. hystrix were found to be rich in eugenol and other phenolic compounds. The EOs evaluated in the present study may have applications in the nutraceutical and pharmaceutical industries.     

Long-term responsiveness to free air CO2 enrichment of functional types, species and genotypes of plants from fertile permanent grassland

To test inter- and intraspecific variability in the responsiveness to elevated CO₂, 9–14 different genotypes of each of 12 perennial species from fertile permanent grassland were grown in Lolium perenne swards under ambient (35 Pa) and elevated (60 Pa) atmospheric partial pressure of CO₂ (pCO₂) for 3 years in a free air carbon dioxide enrichment (FACE) experiment. The plant species were grouped according to their functional types: grasses (L. perenne, L. multiflorum, Arrhenatherum elatius, Dactylis glomerata, Festuca pratensis, Holcus lanatus, Trisetum flavescens), non-legume dicots (Rumex obtusifolius, R. acetosa, Ranunculus friesianus), and legumes (Trifolium repens, T. pratense). Yield (above a cutting height of 4.5 cm) was measured three times per year. The results were as follow. (1) There were highly significant differences in the responsiveness to elevated pCO₂ between the three functional types; legumes showed the strongest and grasses the weakest yield increase at elevated pCO₂. (2) There were differences in the temporal development of responsiveness to elevated pCO₂ among the functional types. The responsiveness of the legumes declined from the first to the second year, while the responsiveness of the non-legume dicots increased over the 3 years. During the growing season, the grasses and the non-legume dicots showed the strongest response to elevated pCO₂ during reproductive growth in the spring. (3) There were no significant genotypic differences in responsiveness to elevated pCO₂. Our results suggest that, due to interspecific differences in the responsiveness to elevated pCO₂, the species proportion within fertile temperate grassland may change if the increase in pCO₂ continues. Due to the temporal differences in the responsiveness to elevated pCO₂ among species, complex effects of elevated pCO₂ on competitive interactions in mixed swards must be expected. The existence of genotypic variability in the responsiveness to elevated pCO₂, on which selection could act, was not found under our experimental conditions. Received: 11 May 1997 / Accepted: 11 August 1997     

Paradiaptomus peninsularis, P. hameri and P. warreni, three new species of Paradiaptomus (Calanoida: Diaptomidae) from South Africa

Three new species of Paradiaptomus from southern Africa are described, Paradiaptomus peninsularis, P. hameri and P. warreni. Paradiaptomus peninsularis occurs in temporary blackwater pools on the peninsula of the Western Cape province, P. hameri in saline pools in the Western Cape province and P. warreni in mountain tarns in the Drakensberg Range in Kwazulu Natal and Lesotho. The genus Paradiaptomus was first established by Sars (1895) for Paradiaptomus lamellatus. There are five described species of Paradiaptomus endemic to Africa ( lamellatus, schultzei, similis, natalensis and rex) and P. greeni from India and Sri Lanka. The three new species have highly-weighted morphological characters which set them apart from each other and from any of the described species of Paradiaptomus.