Restoration of living environment based on vegetation ecology: Theory and practice

The foundation of ecological restoration is how to preserve biocoenoses (i.e. functional ecosystems) and how to restore and reconstruct them where they were destroyed. One of the most important challenges is the restoration of complex, multilayer forests representing the potential natural vegetation. Native forests have functions in disaster mitigation and environmental protection, as well as providing the basis of existence for local people and maintaining gene pools for the future. Through vegetation surveys in Japan and South-east Asia, we have established basic principles in vegetation-ecological restoration of forests. We have been restoring expected disaster-mitigation and environmental protection forests, as experimental reforestation projects, since the 1970s at more than 750 sites throughout the 3000km long Japanese Archipelago, and since the 1980s in parts of South-east Asia, China and South America. The restoration movement has spread from a local activity to a global movement. We aim for the sustainable development of human society through ecological restoration of living environments.     

A vegetation map of The Netherlands,based on the relationship between ecotopes and types of potential natural vegetation

Summary The method of mapping the vegetation on scale 1: 200,000 and the starting points in relation to the potential natural vegetation and ecotopes, are discussed.In view of the planological background of this study, some restrictions have been added to the concept of potential natural vegetation, concerning the period of development and the human influence.The relationship between soil, ground water and vegetation was studied, which resulted in the map of the potential natural vegetation.Each type of potential natural vegetation stands for a series of vegetation types on the same site. Seven main series, with a number of sub-series are distinguished. Within each vegetation series the plant communities have been spread over five groups, according to their structure and naturalness.Ecotopes and ecotope complexes are considered as landscape ecological units. A list of ecotopes was obtained by interpreting topographical maps and by inventory data.The actual vegetation was mapped by estimating the size of the ecotopes within the separate areas. It was expressed in a five figure code for the five groups from the vegetation and ecotopes is combined into the vegetation map of The Netherlands.Interpretation problems, some of them specific for The Netherlands, are discussed and some remarks are made on the necessity of further research.Contribution to the Symposium on Plant Species and Plant Communities, held at Nijmegen, 11–12 November 1976, on the occasion of the 60th birthday of Professor Victor Westhoff.Nomenclature follows Heukels-van Ooststroom, Flora van Nederland, 18e druk, 1975, Wolters-Noordhoff, Groningen; nomenclature of syntaxa follows Westhoff & den Held (1969)     

Restoration of native vegetation following exclosure establishment on communal grazing lands in Tigray,Ethiopia

Questions: Is plant species richness, diversity and above‐ground standing biomass enhanced after establishing exclosures on communal grazing lands? What factors influence the effectiveness of exclosures to restore degraded native vegetation in Tigray, Ethiopia? Location: Northern Ethiopia. Methods: We used a space‐for‐time substitution approach to detect changes in plant species richness, diversity and above‐ground standing biomass after conversion of communal grazing lands to exclosures. We selected replicated (n=3) 5‐, 10‐, 15‐ and 20‐year‐old exclosures and paired each exclosure with an adjacent communal grazing land to ensure that soil and terrain conditions were as similar as possible among each pair. Results: All exclosures displayed higher plant species richness, diversity and biomass than the communal grazing lands. Differences in plant species richness and biomass between an exclosure age and adjacent communal grazing land were higher in oldest than in youngest exclosures. In exclosures, much of the variability in plant species composition and biomass was explained by a combination of edaphic (total nitrogen, phosphorus, texture and soil pH) and site (precipitation and altitude) variables (R²=0.72–0.82). Edaphic and site variables also explained much of the variability in plant species composition in communal grazing lands (R²=0.76–0.82). Our study shows that all exclosures are at an early stage of succession. The increase in economically important indigenous shrub and tree species with exclosure age suggests that, with time, a valuable afromontane forest may develop. Conclusions: Establishment of exclosures on communal grazing lands is a viable option to restore degraded native vegetation. However, before expanding exclosures, the ecological consequences of additional exclosures should be investigated as further expansion of exclosures could increase grazing pressure on remaining grazing areas. Furthermore, consideration of edaphic and site variables will help optimize selection of areas for establishment of exclosures and enhance natural regeneration in exclosures in the future.     

东湖围隔（栏）中水生植被恢复及结构优化研究

为重建湖泊水生植被 ,在武汉东湖无鱼的 2个大型围隔和 1个围栏中进行了水生植被自然恢复和人工结构优化试验 ,两年内 ,围隔 (栏 )中的植被均得以恢复 ,植物月生物量均值均高出对照区约 1倍 ,自然增加的维管束植物比对照区多 3～ 6种 ,漂浮植物易定殖 ,水绵和刚毛藻较易生长 ;自然恢复的植被常以穗花狐尾藻、野菱等为优势种 ,缺乏挺水层 ,群落结构不理想 ,通过合理选种植物 ,可较快地改善其结构 ,加快植被恢复进程 ,经初步实验 ,莲、芦苇、苦草、金鱼藻和穗花狐尾藻适应性较强 ,可作为重建东湖水生植被的先锋种 ,以沉水植物为主体的植被结构较优良 ,控制养鱼是恢复水生植被的前提     

Restoration of wetland vegetation using soil seed banks: lessons from a project in Lake Kasumigaura, Japan

The restoration of degraded wetland ecosystems and the recovery of wetland biodiversity are important global issues. Generally, wetland restoration projects include activities to recover vegetation. A promising revegetation technique is one in which soil seed banks are utilized as the source of plant recolonization. Using such a technique, a pilot project to restore lakeshore vegetation was launched at Lake Kasumigaura, Japan, in 2002. In the project, lake sediments containing the seed banks were spread thinly (∼10 cm) on the surfaces of artificial lakeshores, which were constructed in front of concrete levees and had microtopographic variations. In total, 180 species, including six endangered or vulnerable species and 12 native submerged plants that had disappeared from the above-ground vegetation of the lake, were recorded in five recreated lakeshores (total area, 65,200 m²) during the first year of the restoration. The distribution of each restored species at the sites suggested the importance of microtopographic relief for recolonizing species-rich lakeshore vegetation. Furthermore, the origin of the source seed banks affected the species composition of the restored vegetation. On the other hand, the restoration sites were subject to exotic plant invasions. Here, we report lessons learned from the Lake Kasumigaura restoration project as a contribution to the establishment of ecologically sound revegetation techniques.     

上海园林绿地植被结构与温湿度关系浅析

通过对上海市区园林绿地29个样方的植被结构与微环境及土壤湿度、温度的调查,结果表明,绿地具有明显的增湿降温作用,影响这一作用的主要因素是绿地的乔木植物盖度。土壤湿度与草本植物盖度呈极显著正相关。土壤湿度、温度在一定区间内,呈极显著正相关。复杂完善的植被结构对防止土壤水分蒸发具有较好的效果。     

Patterns of vegetation along the Omo River in southwest Ethiopia

This study investigates the riverine vegetation along the perennial Omo River, which flows from the Ethiopian highlands to its terminus, in the southwestern lowlands, at Lake Turkana (formerly Lake Rudolf). Broadly defined to include the levee backslopes and adjacent mudflats (or ancient floodplains), the riverine zone in the lower Omo basin supports a relatively luxuriant vegetation compared with the dry grasslands in the surrounding plains environments. Habitat conditions along the lower Omo have changed significantly during the past century, primarily due to a period of reduced rainfall and river flow, a drop in lake level (L. Turkana) at the river's terminus and increased exposure of natural levees near the Omo's terminus. The floristic and physiognomic character of riverine vegetation were studied at selected sites, ranging from the relatively straight channel section in the modern delta to a strongly meandering (upstream) section of the river. A combination of open canopy woodland, shrub thicket and grassland (with scattered tree emergents) prevailed on the more recently exposed levees, in and near the modern delta; closed canopy woodland and forest predominated on fore levees in the meandering segment. Floristic diversity was relatively low at all study sites. Ficus sycomorus, Tapura fischeri, Melanodiscus oblongus, Celtis integrifolia and Trichilia roka were most significant in upstream forest sites, whereas Cordia sinensis, Acacia mellifera, Ziziphus mauritiana and Ficus sycomorus were more common in communities nearer the lake. Older forests generally contained greater diversity of more woody species, greater tree height and truck diameter than downstream levee vegetation, but they did not exhibit clear stratification. Species patchiness was broadly characteristic of the riverine zone, particularly the mudflats (ancient floodplains) extending away from the fore levees. Fires are frequently set by local inhabitants throughout the grasslands of the lower Omo Basin; within the riverine zone, they are particularly common in the mudflats but have only limited impact on woodland and forest vegetation. It is suggested that fire is a highly significant factor in the establishment of sharp boundaries between the closed canopy woodland/forest along the river and the more xerophytic vegetation of the mudflats.     

Effects of recent climate trends on the distribution of potential natural vegetation in Central Germany

Introducing climate quotients for the growing season (Q_gs) provides a way to quantify effects of climate trends with respect to Potential Natural Vegetation (PNV), especially beech forests (Fagus sylvatica L.) in Central Germany. What is crucial in this regard is the great influence of the dominant decrease in the amount of precipitation (up to 40% in the last 50 years) during the growing season versus the dormant season. However, precipitation during the dormant season (which is predominantly increasing: up to 40% in the last 50 years) is also important for replenishing the soil water supply. The Q_gs values of the Climatic Normal period of 1971–2000 are generally higher (up to 12% in lowland areas) compared with the Climatic Normal period of 1961–1990, the extent of the difference being in general inversely proportional to elevation above sea level. What this means for the area under investigation is that humidity conditions, which generally improve as the elevation above sea level increases, have a positive effect on the site potential. However, a comparison of the climatologically important period of 1991–2003 with the period of 1961–1990 (area-wide increase between 12% and 16%) could not identify this positive effect of elevation on precipitation for the area under investigation. With regard to the recent climate-based trends of PNV, we have shown that all natural spatial units in Central Germany are affected by progressing continentality (i.e., dryness) during the growing season and the resulting deterioration of the site potential. The area of potential beech forest at lower elevation has decreased in favour of oak forest as PNV, while less change is observed in the montane area.     

A vegetation-ecological approach to the classification and evaluation of potential natural vegetation of the Fagetea crenatae region in Tohoku (northern Honshu), Japan

A new vegetation-ecological approach is proposed for classification and evaluation of vegetation zones by means of phytosociological landscape analysis, based on the potential natural vegetation. The study area is the “Fagetea crenatae region” of the cool-temperate zone of Tohoku (northern Honshu) and the northern parts of Kanto. The area was divided into 953 geographic quadrats on a base map at a scale of 1 ∶ 500000. Based on climax complexes of vegetation in each quadrat, 55 community sub-groups were distinguished as basic units of community complex and vegetation landscapes. The community sub-groups were then grouped into 17 larger community groups by the phytosociological table method. As a result, three phytogeographic vegetation zones (Japan Sea side, inland areas and Pacific side) were classified. For each of these community sub-groups, five geographical and climatic variables (average altitude, mean annual temperature, Kira's warmth index, annual precipitation and mean annual maximum snow depth) were averaged, and the community sub-groups in the same community group, which resembled each other ecologically, were assembled into 28 clusters. The clusters were combined into 11 ecological groups by means of Pearson's similarity ratio of geographical and climatic characteristics. By comparing these ecological groups as a vegetation complex, four phytogeographic vegetation zones (Japan Sea side, inland areas, Pacific side and northern Honshu) corresponding to each potential natural vegetation region with distinct environmental characteristics, were newly classified.     

The role of ecological factors in controlling vegetation dynamics on long temporal scales

Abstract

The pattern of change in the Holocene forests of Europe is outlined and discussed in the light of external and internal forcing factors. Forests are seen as non-linear, dynamic systems, that are, at any point in time, unique and changing. In the absence of human activity, potential forcing factors during the Holocene include (i) climate, (ii) soil development, and (iii) internal forest dynamics. Climate is influential through exerting control on the floristic pool from which forests developed. Current results indicate that the role of soil development is likely to have been minor, but may have slowed rate of invasion and increase of some mid- and late-Holocene forest dominants. Forest change following spread and increase then forces soil change. Internal processes of forest dynamics include competition among existing species, and interactions between existing species and potential invading species. The patterns of interaction may be detectable through rates of change and patterns of increase seen in pollen records. Such processes are seen as being the dominant influence on the pattern of change and the development of forest. Forested systems, such as those in Europe, are strongly influenced by historical events, such as the mid-Holocene decline of elm. Forest composition is likely to be similar, in the broadest terms, from one interglacial to another, but always to vary in detail. The interaction of individuals, populations and environmental variables ensures that, although deterministic, prediction of change will always be difficult.     

Restoration ecology of riverine wetlands: A 5-year post-operation survey on the Rhône River, France

Bibliographical study of articles published in scientific journals over the last 10 years, and of books published over the last 20 years, reveals a clear increase in the number of publications dealing with ecological engineering, particularly on aquatic ecosystems, which today are becoming a major topic. The concept of ecological restoration must be clearly defined scientifically and include adequate pre- and post-restoration monitoring of various performance indicators, to allow for restoration, evaluation and increase its success. A restoration experiment was carried out in a former channel of the Rhône River according to a scientifically based decision framework. Long-term monitoring of aquatic vegetation (17 years of data) on two former channels (reference and restored ecosystem) clearly demonstrated human impacts on aquatic ecosystems. A channel exhibiting rapid terrestrialization and eutrophication processes after completion of a hydroelectric scheme construction was restored. In keeping with the hypothesis, the increase in groundwater supply led the restored ecosystem to return to a less advanced and self-sustainable successional stage, whereas vegetation monitoring in the reference channel did not show significant changes over this 17-year of period, supporting long-term studies to determine the effects of restoration on the biota.     

乌鲁木齐城市半自然植被群落类型及特征分析

根据前人的研究结果,结合典型样地调查,对乌鲁木齐城市半自然植被的群落类型进行了划分,并对群落结构、物种组成和植物生长型谱等特征进行了分析。结果表明:乌鲁木齐城市半自然植类型可划分为4个植被类33个植被型38个群丛组,其中,阔叶林植被类包含8个植被型11个群丛组;灌丛植被类包含12个植被型12个群丛组;草本植被类包含10个植被型11个群丛组;伴人植被类包含3个植被型4个群丛组。属于灌丛植被类的植被型和群丛组均最多,而属于伴人植被类的植被型和群丛组则最少。在该城市半自然植被群落中,阔叶林植被类为二层和三层层片结构,灌丛植被类以二层层片结构为主,草本植被类和伴人植被类为一层层片结构;层片结构类型主要为单一草本型、乔木-灌木型和灌木-草本型。该城市半自然植被群落中共有种子植物24科74属88种,优势科为禾本科(Gramineae)、藜科(Chenopodiaceae)、豆科(Leguminosae)、菊科(Compositae)、蔷薇科(Rosaceae)和十字花科(Cruciferae),共包含47属57种,分别占该群落中种子植物总属数和总种数的63.51%和64.77%。该群落中一年生和多年生草本以及多年生半灌木种类居多,分别占总种数的29.55%、34.10%和17.04%。根据相关研究结果,对乌鲁木齐城市半自然植被与该区域自然植被及人工绿地的差异进行了比较分析。     

Assessing the potential for recovery of lakeshore vegetation: species richness of sediment propagule banks

To assess the potential and develop appropriate techniques for the recolonization of lakeshore vegetation at sites where it had been completely lost, a pilot project was launched at Lake Kasumigaura, Japan. We investigated the species composition and density of the soil seed banks (propagule banks) of lake sediments at nine sites (total area, 65,200 m²) where lake sediments were spread thinly (∼10 cm) on the surfaces of artificial littoral zones. These zones were constructed in front of concrete levees and had microtopographic variations. In total, 180 species, including six endangered or vulnerable species and 12 native submerged plants that had disappeared from the aboveground vegetation of the lake, were recorded during the first year of restoration. The distribution of each restored species at the sites suggested the importance of microtopographic variation for recolonizing species-rich lakeshore vegetation. Furthermore, the origin of the source sediment affected the species composition of the established vegetation.     

接种肉苁蓉对梭梭天然林的影响研究

在新疆准噶尔盆地东南缘广泛分布的平缓低洼地、平缓沙地和半流动沙丘等不同生境类型的梭梭天然林内,进行人工接种肉苁蓉对梭梭天然林影响的试验研究。结果表明,接种肉苁蓉对梭梭天然林林下植被的种类组成、植株数量、植被盖度、物种多样性、生物量以及天然更新的幼苗幼树等都将产生不同程度的影响。其中,在平缓低洼地的梭梭天然林内,因挖接种穴和回填,林下植被的个体数损失4.1×104株.hm-2,占接种前林下植被个体总数的18%;林下植被的生物量损失35.64kg.hm-2,占接种前林下植被生物总量的14.9%;梭梭幼苗幼树的个体数损失1320株.hm-2,占接种前梭梭幼苗幼树个体总数的24.2%。在平缓沙地的梭梭天然林内,林下植被的个体数损失2.6×104株.hm-2,占接种前林下植被个体总数的49%;林下植被的生物量损失39.87kg.hm-2,占接种前林下植被生物总量的19.0%;梭梭幼苗幼树损失345株.hm-2,占接种前梭梭幼苗幼树的18.8%。在半流动沙丘的梭梭天然林内,林下植被的个体数损失2000株.hm-2,占接种前林下植被个体总数的5%;林下植被的生物量损失9.98kg.hm-2,占接种前林下植被生物总量的6.0%;梭梭幼苗幼树损失256株.hm-2,占接种前梭梭幼苗幼树的3.8%。受挖接种穴和回填直接影响的调查样方内,植物个体数减少26%~53%,植被总盖度减少46%~52%,物种多样性下降5%~13%,生态优势度提高2%~6%,梭梭天然更新幼苗幼树减少40%~75%,林下植被地上和地下部分的生物量损失25.2%~55.7%。     

The rise of research on futures in ecology: rebalancing scenarios and predictions

Concern about the ecological consequences of global change has increasingly stimulated ecologists to examine the futures of ecological systems. Studying futures is not only a crucial element of the interaction between science, management and decision making , but also a critical research challenge per se , especially because futures cannot be observed or experimented on. In addition, researchers can encounter methodological and theoretical difficulties, which make interpretations and predictions problematic. In the literature which deals with futures of ecological systems two main lines of research can be distinguished: a predictive approach, which dominates the literature, can be contrasted with a rarer number of studies that elaborate potential scenarios for ecological systems. Scenario approaches currently concern mainly contacts with stakeholders or decision makers, or the use of climate scenarios to derive projections about ecological futures. We argue that a new direction for ecological futures research could be explored by using ecological scenarios in combination with predictive models to further fundamental ecological research, in addition to enhancing its applied value.     

Field surveys on cooling effects of vegetation in an urban area

1. 1. Three kinds of field survey on different scales were carried out in Fukuoka City in summer to examine the relationship between the quantity of vegetation and air temperature.

2. 2. The field of the largerst scale measurement is across the city.

3. 3. Several parks and shrines of various sizes in the city were selected as other measurement areas.

4. 4. The most detailed measurements are carried out in a park with an area of 1.25 ha located in a down town area of the city.

5. 5. Though the amount of vegetation is expressed in a unique way in each survey, it is clearly found that the greener it is, the lower is the air temperature.

Local and regional trends in the ground vegetation of beech forests

We sampled moss and vascular forest vegetation in five ancient beech forests from northwest France, embracing in each a wide array of environmental conditions. Indirect (PCA) and direct (RDA) gradient analysis were used to discern local and regional ecological factors which explain the observed variation in species composition. Our results point to a global factor encompassing a large array of soil and light conditions, unravelled when local particularities of studied forests are singled out. The humus form, numerically expressed by the Humus Index, explains a large part of the observed variation in ground vegetation. Our study confirmed opposite trends in vascular and moss species richness according to humus condition. Ecological factors to which vascular and moss forest species respond at the regional level can be estimated directly in the field by visually inspecting humus forms and vegetation strata despite of the confounding influence of local factors.     

Plant cover estimation based on the beta distribution in grassland vegetation

Cover is the most frequently used measure of abundance in vegetation surveys of grasslands, and various qualitative and semi-quantitative methods have been developed for visual estimation of this metric. Field survey is usually made with a point-grid plate. The frequency distributions of cover derived from point-grid counts follow a beta distribution. Combining point-grid counts from a field survey and the beta distribution for a statistical analysis, we developed an effort-saving cover-measurement method. Cover is measured with a transparent plastic plate on which, for example, 10 × 10 = 100 points are arranged in a lattice with 1-cm grid spacing (thus, one point count represents 1 cm² of cover). N quadrats are set out at randomly dispersed sites in a grassland, and, in each, the plastic plate is used for making counts. The number of grid points located above a given species is counted in every quadrat until the number of counted points reaches a given value c, which is determined in advance. If the number of counted points reaches c in a quadrat, the count is stopped and the quadrat is classified in the category “>c”. In quadrats where c is not attained, full point counts above the species bodies are made. Let g be the number of observed quadrats whose cover is ≤c. Using these g cover measurements and the number of quadrats (N − g) with cover >c, we can quantitatively estimate cover for each species and the spatial pattern index value based on the maximum likelihood method. In trial counts using this method, the time savings varied between 5% and 41%, depending on the shape of the cover frequency distribution. The mean cover value estimates agreed well with conventional measures without a stopping point (i.e., based on full counts of all points in each quadrat).     

Economic issues in the management of plants invading natural environments: Scotch broom in Barrington Tops National Park

Scotch broom (Cytisus scoparius, L.), is an exotic leguminous shrub, native to Europe, which invades pastoral and woodland ecosystems and adjoining river systems in cool, high rainfall regions of southeastern Australia. Broom has invaded 10,000ha of eucalypt woodland in Barrington Tops National Park in New South Wales, and is having a major impact on the natural ecology of the sub-alpine environment. It is extremely competitive with the native flora, retarding their growth and in many areas blanketing the ground and preventing growth of many understorey species in open forest areas. A number of rare and endangered species are believed to be under threat from this invasion. An active program to manage the threat is being implemented by the New South Wales National Parks and Wildlife Service. The management issues relevant to this threat are addressed through the application of a detailed bio-economic model of broom management. The results show that intervention in the management of broom in this natural ecosystem is clearly economically justified, and increases in the existing budgets appear to be justified. A combination of control measures, rather than any single measure, is almost always justified. Attempts to eradicate the broom invasion appear to be undesirable, so containment is the preferable strategy. Further, funding bodies should give assurances of future budget levels. The method of analysis reported here should be applicable to other types of biological invasions.     

Nutrient pools and fluxes of the ground vegetation in coniferous forests due to fertilizing,liming and amelioration

The effects of fertilization and amelioration treatments on some nutrient pools and fluxes of ground vegetation in mature pine and spruce stands on acid soils in South Germany are described. In N-limited pine forests with moderate canopy density and with Deschampsia flexuosa an additional N-accumulation in biomass of 20–40 kg ha^-1 occurred 3 years after pure N-fertilization. The N, P, K-cycling through ground vegetation was stimulated more than 10 years by a combined N + CaCO₃ + P treatment leading toa shift in dominance from cryptogams and Ericaceae towards Deschampsia flexuosa and ruderal species like Epilobium angustifolium. The effect of a lupine treatment (combined with initial soil preparation, liming and P supply) was far stronger than the effect of the other experimental procedures. But the fertilizer and amelioration effects on the herb layer of pine forests tended to decline after two decades for different reasons.The shade-tolerant ground vegetation in a nitrogen-saturated spruce forest was not able to prevent heavy additional nitrate losses from upper mineral soil after dolomitic liming. But the Ca, Mg and K fluxes through ground vegetation were strongly elevated in the third year after treatment.