Short‐term vegetation recovery after alien plant clearing along the Rondegat River,South Africa

The outcomes of ecosystem restoration projects should be periodically monitored to inform subsequent adaptive management decisions. In 2012, a project was begun to remove both invasive alien plants and fish from the Rondegat River in South Africa. Although the initial post‐intervention dynamics of aquatic fauna have been documented, the results of the simultaneous clearing of dense riparian stands of alien trees and shrubs have not been reported. We examined native riparian vegetation recovery over 3 years after alien plant clearing. We documented increased cover of native riparian shrubs, but a simultaneous increase of alien and native weedy grass cover. Secondary invasions, especially by grasses, can have strong effects on ecosystem dynamics and achieving the goals of restoration may therefore require additional active management. Our findings provide an initial baseline reference for future monitoring and adaptive management decisions.     

Vegetation and soil recovery following Eucalyptus grandis removal in Limpopo Province,South Africa

South African terrestrial ecosystems are invaded by hundreds of alien plant species, and large‐scale clearing based on the passive restoration assumption that cleared areas will recover unaided is underway. This study assessed the recovery of vegetation and soil properties, three years following Eucalyptus grandis clearing using fell‐and‐removal and fell‐and‐stackburn methods at Zvakanaka Farm in Limpopo Province, South Africa. The main aim was to ascertain the extent of vegetation and soil recovery, as well as determining which clearing methods facilitate passive vegetation and soil restoration. Results indicate significantly (p < 0.001) lower native species diversity, cover and composition in cleared than in uninvaded sites. However, the recorded low species diversity and composition in cleared sites were more pronounced in the fell‐and‐stackburn than in the fell‐and‐removal sites. Measured soil physical properties varied, with compaction being higher in fell‐and‐removal, whereas soils were more repellent in fell‐and‐stackburn sites. The study concludes that vegetation and soil recovery, following E. grandis clearing, is complex and involves several interacting factors, which are linked to invasion history and intensity. Therefore, for vegetation and soil properties to recover, following E. grandis removal, the clearing programme should consider active restoration techniques, for example soil manipulation and native plant seeding.     

Soil and vegetation recovery following alien tree clearing in the Eastern Cape Province of South Africa

The impact of alien tree clearing on soil and vegetation recovery remains largely understudied. This study focused on changes in soil and vegetation properties following Acacia removal. The aim was to quantify the long‐term consequences of alien clearing. Paired cleared (old – 15 years; medium – 11 years; recent – 6 years) and uncleared sites were selected along the Palmiet catchment in Eastern Cape Province, South Africa. Various soil physico‐chemical properties (soil moisture, pH, P, N, C, K, Na, Ca, Mg and soil repellency) and vegetation diversity measures were studied on 10 m × 10 m plots. Results indicate that measured soil nutrients are significantly (P < 0.05) lower in cleared than in uncleared sites. However, comparisons among cleared sites alone indicate that soil properties are recovering with older cleared sites having higher (P < 0.05) nutrients than recent cleared sites. Soils in uncleared sites are more repellent than soil in cleared sites. Vegetation recovery in cleared sites was taking place with older cleared sites having higher native species diversity than recently cleared site. We conclude that the removal of alien plants could have caused a reduction in soil nutrients. However, as native vegetation recovers on cleared sites, soil nutrients are gradually improving.     

Physiological responses of four herbaceous plants to aluminum stress in South China

Different plants have physiological responses under A1 stress,but there is no systematic study to examine physiological responses of herbaceous plants under Al stress.The aim of this study is to investigate the effect of Al on physiological characteristics of four herbaceous plants,which distributed in red soil area in South China,and to analyze the differences in physiological responses to Al stress between the four herbaceous plants.Four herbaceous plants(Pharbitis nil,Cassia occidentlis,Echinochloa colonum and Aeschynomene indica)were used,and the seed germination percentage,the contents of chlorophyll,proline,and malondialdehyde(MDA),membrane permeability(MP),soluble sugar,and activities of peroxides(POD)and cata lase(CAT)in leaves under five Al3+ treatments(0,80,400,2000,and 10000 mg/L)were assayed with the sand culture method.The results showed remarkable effects of Al3+ on physiological characteristics of these four herbaceous plants.The seeds of all the four species could not germinate at 10000 mg/L.and the growth of all plants were retarded under the 2000 mg/LAr3+ treatment.Compared with the control,2000 mg/L Al3+ significantly(P＜0.05)reduced the contents of chlorophyll a and chlorophyll a+b,and increased the contents of MDA and MP.The content of proline in creased very significantly(P＜0.01)and activities of POD and CAT were depressed.The contents of MDA and MP in leaves of P.nil and A.indica decreased,and the activities of POD and CAT in leaves of the two plants increased under 80mg/L and 400 mg/L.However,the changes in C.occidentlis leaves were opposite to those of the above two plants.The changes in leaves of E.colonum were similar to those of P.nil and A.indica at 80 mg/L.but were opposite to those at 400mg/LAr3+.It is suggested that plants with higher activities of POD and CAT,more contents of chlorophyll and proline,and lower contents of MDA and MP consequently improve the tolerance to Al stress under low and middle Al treatments.     

Physiological responses of four herbaceous plants to aluminum stress in South China

Different plants have physiological responses under Al stress, but there is no systematic study to examine physiological responses of herbaceous plants under Al stress. The aim of this study is to investigate the effect of Al on physiological characteristics of four herbaceous plants, which distributed in red soil area in South China, and to analyze the differences in physiological responses to Al stress between the four herbaceous plants. Four herbaceous plants (Pharbitis nil, Cassia occidentlis, Echinochloa colonum and Aeschynomene indica) were used, and the seed germination percentage, the contents of chlorophyll, proline, and malondialdehyde (MDA), membrane permeability (MP), soluble sugar, and activities of peroxides (POD) and catalase (CAT) in leaves under five Al³⁺ treatments (0, 80, 400, 2 000, and 10 000 mg/L) were assayed with the sand culture method. The results showed remarkable effects of Al³⁺ on physiological characteristics of these four herbaceous plants. The seeds of all the four species could not germinate at 10 000 mg/L, and the growth of all plants were retarded under the 2 000 mg/L Al³⁺ treatment. Compared with the control, 2 000 mg/L Al³⁺ significantly (P < 0.05) reduced the contents of chlorophyll a and chlorophyll a + b, and increased the contents of MDA and MP. The content of proline increased very significantly (P < 0.01) and activities of POD and CAT were depressed. The contents of MDA and MP in leaves of P. nil and A. indica decreased, and the activities of POD and CAT in leaves of the two plants increased under 80 mg/L and 400 mg/L. However, the changes in C. occidentlis leaves were opposite to those of the above two plants. The changes in leaves of E. colonum were similar to those of P. nil and A. indica at 80 mg/L, but were opposite to those at 400 mg/L Al³⁺. It is suggested that plants with higher activities of POD and CAT, more contents of chlorophyll and proline, and lower contents of MDA and MP consequently improve the tolerance to Al stress under low and middle Al treatments. __________ Translated from Acta Phytoecologica Sinica, 2005, 29(4): 644–651 [译自: 植物生态学报, 2005, 29(4): 644–651]     

Landscape connectivity of the grassland biome in Mpumalanga,South Africa

The South African grassland biome is one of the most threatened biomes in South Africa. Approximately 45% of the grassland biome area is transformed, degraded or severely invaded by alien plants and the remaining natural areas are highly fragmented. In this fragmented landscape, the connectivity between habitat patches is very important to maintain viable populations. In this study we aimed to quantify connectivity of the grassland biome in Mpumalanga using graph theory in order to identify conservation priorities and to direct conservation efforts. Graph theory‐based connectivity indices have the ability to combine spatially explicit habitat data with species specific dispersal data and can quantify structural and functional connectivity over large landscapes. We used these indices to quantify the overall connectivity of the study area, to determine the influence of abandoned croplands on overall connectivity, and to identify the habitat patches and vegetation types most in need of maintaining overall connectivity. Natural areas were identified using 2008 land cover data for Mpumalanga. Connectivity within the grassland biome of Mpumalanga was analysed for grassland species with dispersal distances ranging from 50 to 1000 m. The grassland habitat patches were mostly well connected, with 99.6% of the total habitat area connected in a single component at a threshold distance of 1000 m. The inclusion of abandoned croplands resulted in a 33% increase in connectivity at a threshold distance of 500 m. The habitat patches most important for maintaining overall connectivity were the large patches of continuous habitat in the upper and lower centres of the study area and the most important vegetation types were the Wakkerstroom Montane Grassland and the Eastern Temperate Freshwater Wetlands. These results can be used to inform management decisions and reserve design to improve and maintain connectivity in this biome.     

河岸带农田不同恢复年限对土壤碳氮磷生态化学计量特征的影响——以温榆河为例

弃耕地撂荒是土壤与植被向自然方向进行的次生演替,研究河岸带土壤撂荒后碳氮磷生态化学计量特征,是恢复和重建由农田干扰导致的退化河岸带生态系统的重要科学基础之一。以河岸带农地为对照,不同撂荒年限(撂荒2年、撂荒8年、撂荒10年)的土壤为研究对象,探索不同撂荒年限对土壤碳、氮、磷含量及相互关系的影响。结果表明:(1)土壤有机碳、氮的含量均呈现撂荒10年>撂荒8年>农田>撂荒2年;土壤中磷含量呈现撂荒10年>撂荒8年>撂荒2年>农田;农田和各撂荒年限的土壤碳、氮、磷含量,均随着土层深度的增加而呈降低的规律,但土壤碳和氮差异的显著性比磷明显。(2)河岸带土壤中C/N、C/P的均值均呈现:撂荒10年>农田>撂荒8年>撂荒2年趋势。N/P的均值呈现:撂荒10年(0.78)>农田(0.77)>撂荒8年(0.77)>撂荒2年(0.67),表明N是本研究区河岸带植被恢复的限制性营养元素。(3)河岸带农田和不同撂荒年限土壤碳、氮含量均存在极显著的耦合线性关系,而碳与磷、氮与磷之间的线性拟合程度相对较低。(4)在农田撂荒演替的初期阶段(2...     

Sourcing native plants to support ecosystem function in different planting contexts

Current guidance on sourcing native plants to support ecosystem function focuses on the high risk of failure when unsuitable material is used in ecological restoration. However, there is growing recognition that risks may be lower and rewards higher at highly disturbed sites isolated from remnant populations, especially when considering support for pollinators, wildlife, and other ecosystem functions. We developed the first decision support tool using expert opinion to assess suitability of different native plant sources, including horticultural cultivars, in two different planting contexts. We assessed the suitability of 761 sources for 72 commonly sold native species in two different planting contexts (small, isolated, highly disturbed sites vs. large, undisturbed sites near remnant populations). Information on genetic and adaptive backgrounds of sources was strikingly lacking, forcing us to exclude one‐third of sources from our assessment. While only 3% of cultivars received high suitability scores for use in large, undisturbed sites near remnant populations, 52% received high suitability scores in small, isolated, highly disturbed sites. However, nearly 25% of cultivars had floral or leaf traits that differed from wild plants in ways that may compromise their ability to support pollinators and other wildlife. Forbs and cultivars lacking genetic diversity and source information were most likely to have altered traits. We recommend that native plant breeders and sellers work together to ensure ecosystem function, adaptation, and diversity information is available to consumers, that consumers request this information to drive demand, and that researchers further investigate how context influences risks and benefits of different sources.     

The effect of seeding densities on old cultivated fields in Marakele National Park,Thabazimbi, South Africa

Large areas of the bushveld bioregion are converted from natural rangeland to cultivated fields for economic purposes. Conversion of grasslands to agricultural land alters the vegetation structure, plant species composition and ecological functioning. The aim of this paper was to evaluate the effectiveness of different seeding densities to enhance the restoration of old cultivated fields in Marakele National Park. Before these areas along the Motlhabatsi River were incorporated into the Park they were used for cultivation of crops. In an attempt to restore these areas to an improved condition, this pilot study was undertaken to determine best practice. One study area comprising two experimental sites and one control site were selected. A seed mixture consisting of natural grass species to the area was selected and sown at two different seed densities. The sites were monitored for a 2‐year period for species diversity and composition. Data were analysed using the analysis of variance (ANOVA), while species diversity was calculated for the different experimental sites using the Shannon–Wiener index. Limited differences were observed between the two seeding densities. The results indicate that seeding degraded grasslands in these bushveld areas enhance the diversity and evenness of the degraded land.     

Comparing ecological restoration in South Africa and Western Australia: the benefits of a ‘travelling workshop’

Researchers and practitioners of ecological restoration from South Africa and Western Australia recently undertook a travelling workshop across several South African biomes to discuss and evaluate the various approaches currently being utilised in the field. Key findings from the workshop highlighted the contrasting nature of ecological restoration undertaken in these two ecologically similar, but socially and politically different regions.     

From a Howling Wilderness to Howling Safaris: Science,Policy and Red Wolves in the American South

This article details the complex natural and cultural history of red wolf (Canis rufus) restoration in the American South. The decisions and methods utilized in the red wolf’s recovery after 1960 were unprecedented and creative but not geographically limited. The federal red wolf recovery experiment highlights the debate over what constitutes a species in a dynamic world, and the practical challenges and unexpected results in endangered species management in peopled landscapes. This wildlife restoration story illustrates not only the “hands-on” management role humans played, and continue to play, but also reveals cultural assumptions about what constitutes a “wild” wolf and about the necessity of wilderness. The red wolf recovery project provides constructive lessons for future species restoration involving flora and fauna on public and private land, and demonstrates human and animal engagement in the making of nature and culture.     

Ethnobotanical plant uses in the KwaNibela Peninsula, St Lucia, South Africa

Ethnobotanical field studies were conducted for the first time in the KwaNibela Peninsula of southern Maputaland, KwaZulu-Natal, to document indigenous knowledge about useful plants. The vernacular names and uses of 82 plant species were recorded and compared to published Zulu and Swazi knowledge. Medicines for skin disorders, toothache, wounds, worms, chest and throat ailments, infertility and purgatives are still commonly used. Superstition and divination play a major role in the traditional knowledge system of the people of KwaNibela with 24 plants used for this purpose. Three KwaNibela medicinal plants (Erythroxylum delagoense, Putterlickia verrucosa, and Teclea natalensis) appear to be new records, not previously reported in the general scientific literature. The list also includes 61 novel uses of plants and another 15 new variations on known (published) uses. Ten previously unpublished vernacular names are presented, together with an additional 19 new variants of known names. These new additions to the scientific literature confirm that indigenous knowledge in KwaZulu-Natal is not yet completely recorded.     

Potent anti-mycobacterial and immunomodulatory activity of some bioactive molecules of Indian ethnomedicinal plants that have the potential to enter in TB management

Tuberculosis (TB) is one of the deadliest infectious diseases of human civilization. Approximately one-third of global population is latently infected with the TB pathogen Mycobacterium tuberculosis (M.tb). The discovery of anti-TB antibiotics leads to decline in death rate of TB. However, the evolution of antibiotic-resistant M.tb-strain and the resurgence of different immune-compromised diseases re-escalated the death rate of TB. WHO has already cautioned about the chances of pandemic situation in TB endemic countries until the discovery of new anti-tubercular drugs, that is, the need of the hour. Analysing the pathogenesis of TB, it was found that M.tb evades the host by altering the balance of immune response and affects either by killing the cells or by creating inflammation. In the pre-antibiotic era, traditional medicines were only therapeutic measures for different infectious diseases including tuberculosis. The ancient literatures of India or ample Indian traditional knowledge and ethnomedicinal practices are evidence for the treatment of TB using different indigenous plants. However, in the light of modern scientific approach, anti-TB effects of those plants and their bioactive molecules were not established thoroughly. In this review, focus has been given on five bioactive molecules of different traditionally used Indian ethnomedicinal plants for treatment of TB or TB-like symptom. These compounds are also validated with proper identification and their mode of action with modern scientific approaches. The effectiveness of these molecules for sensitive or drug-resistant TB pathogen in clinical or preclinical studies was also evaluated. Thus, our specific aim is to highlight such scientifically validated bioactive compounds having anti-mycobacterial and immunomodulatory activity for future use as medicine or adjunct-therapeutic molecule for TB management.     

The potential of South African plants in the development of new food and beverage products

A review is presented of the history and recent trends in the exploration and development of food plants in southern Africa. The opportunities for developing new crops and new products for local and international markets are discussed. More than 120 species with potential as new food and beverage products (including functional foods, herbal teas and new flavours) are listed and a subjective rating of the commercial potential is provided for each of them. Some noteworthy examples are discussed and illustrated, including several indigenous fruits and vegetables that are as yet poorly known. There is a growing awareness of the importance of indigenous plants in new product development and numerous new products are already being developed. Basic research in botany (to guide genotype selection), horticulture (to develop new crops), food science (to focus on nutritional analyses) and marketing (to understand and develop new marketing approaches) is mentioned as important priorities.     

Relationships between the density of two potential restoration tree species and plant species abundance and richness in a degraded Afromontane forest of Kenya

In recent years, there have been considerable efforts to restore degraded tropical montane forests through active restoration using indigenous tree species. However, little is known about how these species used for restoration influence other species. In this study, two potential restoration species, Albizia gummifera and Neoboutonia macrocalyx, are investigated with regard to the relationship between their density and the abundance and richness of other plant species. The study was conducted in a degraded forest consisting of disturbed transition zones and secondary forest. Our results show positive relationships between the density of A. gummifera and the abundance of tree seedling and sapling richness in the transition zones and in the secondary forest. Shrub richness was negatively related to the density of A. gummifera. Abundance and richness of tree saplings and shrubs were positively related to N. macrocalyx density both in the transition zones and in the secondary forest. Herb species richness declined with N. macrocalyx density in the transition zones but increased with N. macrocalyx density in the secondary forest. The positive relationships between the density of the two tree species and species richness of other woody species suggest that both A. gummifera and N. macrocalyx can be suitable for active restoration of degraded mountain forests within their natural range.