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Plant diversity and composition of rice field bunds in Southeast Asia
Abstract
Which plant species can be found on rice field bunds and what are the prevailing life forms? Which plant communities occur and what are the main environmental drivers and phytogeographic patterns shaping these communities? How do species diversity and composition differ between bunds and paddies? To answer these questions, 133 vegetation relevés using the Braun-Blanquet method were collected in lowlands and uplands of Vietnam and the Philippines between 2012 and 2015. Soil samples were collected and farmers were interviewed. Properties of soil, climate, and geography were assessed, further structural parameters, landscape heterogeneity, seasonality, management and intensity of cultivation. Hierarchical UPGMA cluster analysis and NMDS ordinations were performed to visualize variation in plant community composition and the determinants. We found 302 vascular plant species, of which 94 species are red listed by the IUCN (under category “Least concern”). Therophytes and helophytes are the prevailing life forms. Six clusters of plant communities were classified, and temperature, soil acidity, land use intensity and nutrient availability were identified (according to relevance) as explanatory variables. Bunds revealed higher species richness than paddies and bunds in mountain areas were more species-rich than those in the lowlands. We conclude that the composition of bund communities provides valuable information on environmental and biogeographical conditions of the local rice landscapes, and that it is probably the best applicable and most reliable indicator of management intensity.
... Изучение сегетальной растительности рисовых полей с позиций эколого-флористического подхода Ж. Браун-Бланке проводили в основном в 1950-1990-х гг. Сообщества описаны и приведены в классификационных схемах разных регионов Азии -в Японии (Miyawaki, 1960), Южном Таиланде (Nowak et al., 2015), Центральном Непале (Nowak et al., 2016), Северной Корее (Kolbek et al., 1996;Kolbek, Jarolímek, 2013), Таджикистане (Nowak et al., 2013), во Вьетнаме и на Филиппинах (Fried et al., , 2018, а также в Европе -в Испании, Португалии, Андорре Ninot et al., 2011;, Венгрии , Франции, Италии, Румынии (Piccoli, Gerdol, 1981;Carre tero, 1989;, Болгарии (Gussev et al., 2020), Украине (Dziuba, 1989(Dziuba, , 1996Dubyna et al., 2019). ...
... Наибольшее количество ассоциаций, субассоциаций или безранговых сообществ, описанных с позиций эколого-флористического подхода Ж. Браун-Бланке, выделено в Восточной (Япония), Юго-Восточной (Таиланд, Непал, Вьетнам, Филиппины, Северная Корея, Китай, Индонезия) и Средней Азии (Таджикистан). В последние десятилетия описаны новые синтаксоны, специфические для рисовых полей этих регионов (Kolbek, Jaro límek, 2013;Nowak et al., 2013Nowak et al., , 2015Nowak et al., , 2016Fried et al., , 2018 , Испании и Португалии , Каталонии и Андорры (Ninot et al., 2011) - , тогда как для территории Украины (Dziuba, 1996;Dubyna et al., 2019), Крымского полуострова (Dziuba, 1996;Bagrikova, 2016), Ростовской обл., Краснодарского края (Dziuba, 1989), Нижнего Поволжья (Golub, Kuzmina, 1997;Golub, Maltzev, 2013) сообщества Echinochloo-Oryzetum sativae, Oryzo-Cyperetum difformis приводятся в ранге отдельных ассоциаций. Кроме того, в Северном Причерноморье, в том числе в Ростовской обл. ...
... The largest number of the described basic syntaxa (associations, subassociations or communities) are allocated in Eastern, South-Eastern and Central Asia. Lots of new syntaxa specific to the rice fields were described in Japan (Miyawaki, 1960), Southern Thailand (Nowak et al., 2015), Central Nepal (Nowak et al., 2016), North Korea (Kolbek et al., 1996;Kolbek, Jarolímek, 2013), Tajikistan (Nowak et al., 2013), Vietnam and the Philippines (Fried et al., , 2018, many of which have been assigned in the alliance Ludwigion hyssopifolio-octovalvis A. Nowak, S. Nowak, Nobis 2015, the order Cypero-Echinochloetalia oryzoidis O. de Bolòs et Masclans 1955, the class Oryzetea sativae. The rice communities described in Western (Spain, Portugal, Andorra, Italy, France, Hungary, Romania, Bulgaria) and Eastern (Ukraine, Russian Federation) Europe which differ in species composition from those in Asian regions are assigned to the alliance Oryzo sativae-Echinochloion oryzoidis O. de Bolòs et Masclans 1955 within the above order and class. ...
According to the Braun-Blanquet approach the segetal communities of rice agrocenoses of Eurasia belong to the class Oryzetea sativae Miyawaki 1960, although there is a lot of species that are diagnostic of different classes — Phragmito-Magnocaricetea Klika in Klika et Novák 1941, Lemnetea O. de Bolòs et Masclans 1955, Potamogetonetea Klika in Klika et Novák 1941, Bidentetea Tx. et al. ex von Rochow 1951, etc. The largest number of the described basic syntaxa (associations, subassociations or communities) are allocated in Eastern, South-Eastern and Central Asia. Lots of new syntaxa specific to the rice fields were described in Japan (Miyawaki, 1960), Southern Thailand (Nowak et al., 2015), Central Nepal (Nowak et al., 2016), North Korea (Kolbek et al., 1996; Kolbek, Jarolímek, 2013), Tajikistan (Nowak et al., 2013), Vietnam and the Philippines (Fried et al., 2017, 2018), many of which have been assigned in the alliance Ludwigion hyssopifolio-octovalvis A. Nowak, S. Nowak, Nobis 2015, the order Cypero–Echinochloetalia oryzoidis O. de Bolòs et Masclans 1955, the class Oryzetea sativae. The rice communities described in Western (Spain, Portugal, Andorra, Italy, France, Hungary, Romania, Bulgaria) and Eastern (Ukraine, Russian Federation) Europe which differ in species composition from those in Asian regions are assigned to the alliance Oryzo sativae–Echinochloion oryzoidis O. de Bolòs et Masclans 1955 within the above order and class. The paper represents the first results of the classification based on 20 relevés of rice communities studied in 2018 in the Gudermessky and Shelkovskoy districts of the Chechen Republic, located on the northern slope of the Great Caucasian Ridge, the Chechen Plain and the Terek–Kuma Lowland. The areas under rice crop rotation are kept at an altitude of 20–35 m above sea level both in the north and in the plain part, mainly in the interfluves of the Terek and Sunzha rivers. The climate in the rice-growing areas is continental, insufficiently humid, with the very warm summers and moderately mild winters and the lot of heat and dryness in the summer months. The mean year temperature is 10.8 °C, during the growing season of rice (May–September) — 20.8 °C; the sum of effective temperatures above 15 °C is about 3100–3400 °C (Tulyakova, 1973; Ryzhykov et al., 1991); the annual amount of precipitation is 400—450 mm with less than 270 mm in summers. The largest areas on the Terek and Sunzha river interfluve are occupied by intrazonal meadow and swamp vegetation. There are two associations and one community belonging to the alliannce Oryzo sativae–Echinochloion oryzoidis have been established within study area. The associations Echinochloo–Oryzetum sativae Soó ex Ubrizsy 1948 (Table 2, rel. 1–8) and Oryzo–Cyperetum difformis Koch 1954 (Table 2, exp. 9–14) are widely distributed in rice fields in Western and Eastern Europe, while the community Setaria pumila–Oryza sativa (Table, rel. 15–20) is a new one. On cultivated lands, the composition and structure of segetal communities depends on the intensity of agrotechnical measures, as well as on the depth and duration of flooding. The species diversity of the communities adjacent to the fields, formed in the discharge channels and on the dams between rice bays, have a significant impact. In the rice fields in the presence of chemical and agrotechnical processing, communities of the ass. Echinochloo–Oryzetum sativae prevail, and the communities of the ass. Oryzo–Cyperetum difformis and Setaria pumila–Oryza sativa are formed where this impact is not strong. The significant participation of Cyperus glomeratus is a distinctive feature of the Chechen Republic segetal communities from the analogous ones compare with the other regions of Europe.
... Rice weed management and cultivation practices differ most strongly between lowland and upland regions rather than between countries (De Datta, 1981;GRiSP, 2013;Fried et al., 2017Fried et al., , 2018: rice is usually harvested twice a year in lowland regions, whereas the mountain climate allows for only one crop cycle per year. Intensive manual labor, the use of traditional upland rice cultivars and reduced or zero input of synthetic herbicides and fertilizers are further characteristics of the traditional upland rice farming systems in Ifugao (PH3) and Lao Cai (VN3). ...
... The local farmland flora may also be enriched due to overlapping altitudinal distribution ranges of temperate/subtropical and tropical plant species in mid-elevations, as reported in studies on the diversity of introduced plants from other tropical mountain areas (Jakobs et al., 2010;Tassin and Rivière, 2003). Fried et al. (2017Fried et al. ( , 2018 found several genera in the species pools of PH3 and VN3 that are common to temperate regions. At some sites, the negative effects of high temperatures may be weakened by advantageous macro-and microclimatic conditions. ...
... Regional rice weed diversity surely profits from specific traditional cultivation methods and high local landscape heterogeneity. Recently, Fried et al. (2017Fried et al. ( , 2018 documented the distinct weed control and cultivation methods of each study region. Land use practices and intensity vary so greatly among regions that no region-independent variable with general effects on the plant diversity was detected. ...
Rice ecosystems vary greatly in climate, edaphic conditions, landscape heterogeneity, agricultural management and biodiversity. However, ongoing land use intensification and conversion to large-scale monoculture are threatening this diversity. We analyzed how rice-growing regions in Southeast Asia differ in diversity and composition of vascular plants in paddy rice ecosystems, and how the local and regional biodiversity of these plants is determined by variations in abiotic conditions, habitat type (paddy vs. bunds) and the proximity of non-paddy habitats. The vegetation of paddies and their bunds was surveyed in seven important rice production regions located in highlands and lowlands of Vietnam and the Philippines. Within the regions we sampled 67 pairs of study sites comprising a total of 122 paddies and 134 bunds. We identified major drivers of field-level weed diversity (alpha diversity) separately for bunds and paddies. Species turnovers (beta diversity) across sampling sites, between paddies and their bunds, and between regions were visualized using the Bray-Curtis coefficient of dissimilarity and DCA ordinations. Species richness on bunds was mainly influenced by the proximity of non-paddy habitats, mean annual temperature and soil acidity. Soil moisture was the decisive factor for the variation in paddy weed richness. In both habitat types, Shannon diversity and the number of insect-pollinated plants showed patterns similar to species richness. Regional differences in plot species richness were stronger on bunds than in paddies. Species turnover was high among habitat types and between upland and lowland regions. Future ecological engineering approaches can build on our findings to promote pollination services more efficiently in Southeast Asian rice landscapes.
... Forests are essential for human survival and the economy around the world. Forest land is defined as land with at least 0.5 hectares of land area having a potential canopy cover of 10% and at least 5m of potential tree height (FAO 2000;Korhonen et al., 2006). The global forest area decreased by 3%, from 4128 million hectares (Mha) in 1990 to 3999 Mha in 2015. ...
... They can enhance soil properties which include organic carbon, nitrogen, phosphorus, and potassium, leading to improved plant growth (Kanannavar et al., 2020). On the other hand, troughs are designed to supply nutrient-enriched water to plants at inaccessible heights (Fried et al., 2018). They ensure a continuous water supply to the plants, which is essential for their growth and development (Khosravi et al., 2016). ...
Deforestation poses a serious environmental threat turning huge vegetative areas into barren lands in Pakistan and may also cause the extinction of native plant species and wildlife. Pothowar plateau being located in the semiarid zone of Pakistan is severely affected by erosion because of less forest cover and less rainfall resulting in large areas shifting to barren lands. Deforestation, unpredictability, and short durational rainfall are the key causative agents. Dry afforestation is a well-known technique for land reclamation in arid and semi-arid areas. Dry afforestation is an efficient way of utilizing rainwater for tree growth and increasing vegetative cover. This research was conducted in Attock (located in the Pothowar plateau). The research duration was one year (February 2022-2023). The main objective of this research was the evaluation and comparison of dry afforestation techniques in terms of indigenous vegetation growth so that rainwater can be utilized to the maximum extent. Two different dry afforestation techniques including troughs and bunds were tested to reclaim the barren area. Three indigenous species including Acacia nilotica, Acacia modesta, and Dodonaea viscosa were selected for study purposes on dry afforestation techniques. The performance potential of both techniques was evaluated based on different plant growth parameters. Results from plant growth data concluded that, in terms of plant height Dodonaea viscosa and Acacia nilotica performed better on troughs while Acacia modesta performed better on bunds with significant variation in Acacia modesta and Acacia nilotica tree species. In terms of the number of leaves, there was no significant variation found after analysis however Dodonaea viscosa and Acacia nilotica performed better on bunds while Acacia modesta performed better on troughs. In terms of the number of branches Dodonaea viscosa and Acacia nilotica performed better on bunds while Acacia modesta showed better growth on troughs.
... Coordinates of relevés: GPS (° ʹ ʹʹN, ° ʹ ʹʹE), altitude (m), occurrence species: Fried et al. 2018). The salinity of the habitat of the P. japonica-T. ...
Purpose
The Deonggae coast on Jeju Island is a unique habitat that has not yet been studied from an ecological management or conservation perspective, despite its importance as the northernmost habitat of subtropical plants in Asia and the sole habitat of an endangered fern, Thelypteris interrupta, in Korea. To provide insights into this habitat’s systematic management, we comprehensively characterized its abiotic and biotic components.
Methods
Our study found two distinct plant communities (Persicaria japonica-Thelypteris interrupta and Thelypteris interrupta-Phragmites australis), driven by their respective microhabitats and influenced by soil inundation frequency, water depth, and salinity. We examined the phytosociological similarities and habitat characteristics of these two communities.
Results
Thelypteris interrupta could be distributed in the northernmost part of the Deonggae coast due to its greater heat preference. However, this limits its spread toward polar regions. We suggested minimizing the transformation of wetlands into terrestrial habitats by reducing the introduction of external soils and establishing ecological continuity with neighboring ecosystems while educating visitors about the area’s ecology as two habitat conservation practices.
Conclusion
The Deonggae coast is a natural wetland with a high conservation value as a habitat for endangered wildlife and a refuge for opportunistic species under the influence of climate change.
... In the siltamended peatland, the soils not only keep a portion of seeds of peatland species, but also have additional upland and agriculture weed species such as Eriochloa villosa and Echinochloa crusgalli. These species are common in paddy field and spread rapidly (Fried et al., 2018), which result in the increasing seed density in the soil seed bank of these species in the silt-amended peatland. ...
Peatlands have declined dramatically in the past century due to agricultural cultivation. The main goal of this study was to assess the impact of soil amendment during farming on the restorability of peatlands. We compared the soil seed banks between the natural peatland and farmed peatlands with two soil amendment types (sand-amended and silt-amended) in the Changbai Mountains, China. We found that the seed density and species richness in silt-amended peatland were higher than the natural peatland, and they were the lowest in the sand-amended peatland. Carex species are foundational species of these wetlands and these dominated both in standing vegetation and soil seed banks of the natural peatland. Carex spp. occurred in the seed banks of silt-amended peatland soils in low seed density, but were absent in the sand-amended peatland. The seed density of peatland species was highest in the surface 10 cm soil depth in the natural peatland, while it was highest in the 10-20 cm soil depth in the silt-amended peatland. Redundancy analysis identified that soil C:N, soil water content, and soil organic carbon explained most variance in seed bank composition. The result illustrates that soil amendment types affect soil, and change soil seed banks and revegetation potentials of peatlands. The silt-amended peatland had a higher revegetation potential than the sand-amended peatland. Removal of surface silt mineral soil is necessary to reduce the weed seeds and promote the recolonization of peatland species in the silt-amended peatland during restoration.
... Structural heterogeneity occurs in rice production areas because the landscape can be composed of irrigated/non-irrigated rice paddy fields, fallows (i.e., uncultivated fields), and bunds (i.e., small earthen dikes used as pathways and water barriers that are colonized by a variety of terrestrial plants [9]). The specific conditions associated with different subunits of rice field landscapes are likely to impact the decomposition of animal carcasses as well as the composition of carrion-related species, thus affecting the succession of carrion-related arthropods on vertebrate remains. ...
Although rice production landscapes are often the scene of homicides, vertebrate decomposition and associated arthropods have never been described from rice paddies. Tropical rice landscapes are typically composed of irrigated/non-irrigated rice fields, fallow land (i.e., uncultivated fields), and low earthen levees (bunds) used as access pathways. The specific microclimatic and environmental conditions associated with each subunits of rice field landscapes are likely to impact carcass decomposition as well as the arthropod species associated with carrion. Here, we tested the hypothesis that the combined effects of constraints on arthropod colonization and survival, scarcity of necromass, limited habitat architecture, and recurrent disturbance limit the ability of carrion-related arthropods to colonize corpses and large carcasses in tropical rice-fields. Our results from monitoring pig carcasses in Philippine rice fields indicated that vertebrate decomposition in irrigated fields was slower and incomplete when compared to non-irrigated fields and bunds. Carcasses were colonized by a small complex of carrion-related arthropods that differed in composition and relative species abundance between dry bunds and relatively humid rice paddies. Fire ants (Solenopsis germinata) were observed frequently on carcasses exposed on bunds, rarely in non-irrigated fields, and almost never in irrigated fields. The presence of fire ants was associated with reduced blow fly (Chrysomya megacephala) abundance. Taken together, this indicates that the arthropod fauna associated with carcasses in tropical rice fields is relatively simple in contrast to the generally high arthropod diversity reported for other ecosystems at tropical latitudes. The limited richness of the community also means that an understanding of the development of one abundant calliphorid blow fly, C. megacephala, may be sufficient to investigate deaths and homicides under conditions similar to the ones described in this study.
... Paddies revealed higher species richness in mountain areas than those in the lowlands (Fried et al., 2018). In the present study, Tonglu county, located in a maintain area, with an upland climate and soil type, exhibited weeds species richness 33 higher 10), which demonstrate that they exhibited good community status within the study area. ...
The study aims to characterize weed communities and identify differences in species diversity in counties using machine-transplanted paddy fields (MTPs) in areas of rice-wheat rotation in northern Zhejiang Province (NZP), P.R. China. Values of weed relative abundance (VRA), species biodiversity (SB), breadth of ecological niche (BEN) and overlap values of ecological niche (OVEN) were analyzed. The results indicated that there were 43 weed species belonging to 30 genera of 15 families, the majority being part of Gramineae and Cyperaceae. Species biodiversity in Tonglu county was significantly higher, with greater species richness, Simpson, Shannon-Wiener, and Pielou indices compared to other counties in terms of weed distribution. Hierarchical cluster analysis revealed that the weed species in NZP were divided into four principal groups. BEN analysis demonstrated that predominant weeds such as Leptochloa chinensis (L.) Nees and Echinochloa crus-galli var. mitis (Pursh) Petermann displayed higher BEN values. OVEN analysis indicated that 76.1% of the 276 pairs exhibited a niche overlap value > 0.7, suggesting that there was great similarity in resource utilization between the majority of weed species pairs. The results will help local farmers to adopt more integrated management practices in MTPs, allowing the vegetation to provide various ecosystem services.
... While all of the plant-and leafhopper species found here feed preferentially but not exclusively on rice, the species effect was driven in large by N. nigropictus, which has the widest diet of any herbivore species collected. Its diet includes C4 plants such as Echinochloa colona and Polytrias indica (Dale 1994;Caton et al. 2010), found among the ruderal C4 grasses along field margins (Fried et al. 2018) and known to be used as additional food resources by N. nigropictus (Dale 1994;Schoenly et al. 2010). ...
Spiders are important bio-control agents of rice insect pests such as plant- and leafhoppers. To investigate temporal changes in spider prey and variations in prey due to landscape structure around rice fields, carbon and nitrogen stable isotopes of rice field arthropods were analysed over three consecutive sampling dates during the rice cropping season. Initial isotope composition of gnats and midges emerging from submersed rice fields indicates a larval algae diet, while later values suggest a switch to rice-derived carbon. Initial δ13C values of plant- and leafhoppers were higher in fields of rice-heterogeneous landscapes, indicating migration from source populations feeding on C4 grasses into rice fields; later, their δ13C values approached those of rice. Isotope values of web-building and cursorial spiders in the earliest samples indicate aquatic gnat and midge prey. The later shift toward terrestrial herbivore prey was more pronounced for small than for larger species and in rice paddies near permanent vegetation, indicating use of prey from the surrounding landscape. The results suggest that rice field spiders are supported by three different carbon pools: (1) aquatic carbon originating from algae and (2) legacy carbon from previous growing cycles, both incorporated via between-season predation on gnats and midges, and (3) carbon from the current rice season incorporated via herbivore prey. In conclusion, fostering aquatic midge and gnat larvae, e.g. via mulching, and integrating rice fields into rice-heterogeneous landscapes likely strengthens biological control of pest species in rice paddies by supporting high populations of spiders between cropping seasons.
Recently, people have started growing wild vegetables in mainland Southeast Asia despite the abundance of domesticated ones. In this study, we analyzed the drivers for this trend by targeting wild paddy field plants in the Lao People’s Democratic Republic. Surveys were conducted on the use, domestication status, and market status of plants, and cultivation skill of the growers in Vientiane Municipality/Province and Houaphan Province, by targeting 171 market vendors and 54 growers, in 2013–2019 and 2022. A total of 31 paddy field plants were used as vegetables, of which 7 were grown. Centella asiatica, Limnophila chinensis, Limnophila geoffrayi, and Houttuynia cordata have been grown since the 2000s for selling at local markets, and because of demand for safe and healthy vegetables, time saved in traveling to harvesting sites, or ease of cultivation. The possible drivers for growing them were the preference for wild foods in Lao dietary culture, emerging concerns about agricultural chemical use on commercially produced vegetables, increased trade of wild plants at local markets, the ease with which these plants can be vegetatively propagated, and their resistance to pests and diseases. The results of this study have implications for food security, plant conservation, and domestication research.
Soil bunds are important agricultural infrastructure of sloping farmlands in the Three Gorges Reservoir Area and play an essential role in controlling hillslope soil erosion. However, the functionality of this infrastructure has been largely impaired by structural instability induced either by external forces or inherent mechanical failure. This study aims to determine the friction properties of the root–soil interface and infer the optimal herbs for its stability maintenance. Soil bunds with three kinds of plating herbs including barnyard grass, crabgrass, and goosegrass were selected. The root–soil friction mechanism of the three herbs was examined by direct shear force testing under different soil moistures (i.e., 5%, 10%, 15%, 20%, and 25%) and soil bulk densities (i.e., 1.25, 1.35, and 1.45 g cm−3). (i) The friction properties were lower at the rootless soil interfaces than at the root–soil interfaces. Direct friction properties were higher at the root–soil interface for goosegrass than for the other two plants. (ii) Grass roots can considerably improve soil shear strength under low (5%) and high (25%) soil moisture conditions. The relationship between the friction properties and soil moisture can be described using binomial functions. (iii) The constitutive relationship between shear strength at the root–soil interface and vertical load can be expressed by a hyperbolic model that satisfies the Mohr–Coulomb criterion. These findings can be used as references for controlling the friction properties of soil bunds and screening grasses for slope protection in the Three Gorges Reservoir area.
Irrigated rice landscapes in tropical and subtropical Asia are complex agroecosystems that have evolved mostly from natural wetlands. Millennia of interaction between human communities and their surrounding ecosystems have shaped these highly-dynamic and diverse environments that provide several valuable ecosystem services and host a diversity of plants, animals and habitats. However, this biodiversity is threatened by ongoing agricultural intensification and the conversion of vast farmland areas to monoculture crop production. Besides, the knowledge on the diversity and composition of plants in rice ecosystems and the occurring rice weed communities is still inadequate. This thesis aimed at a more comprehensive understanding of the diversity, composition, dynamics and distribution of rice weed communities in important rice-producing regions of Southeast Asia. Research focused on seven regions in Vietnam and the Philippines which are greatly varied in terms of climate, edaphic conditions, landscape heterogeneity, agricultural management and biodiversity. I examined two major habitat types of rice ecosystems, i.e. paddies (the field proper) and bunds (or levees), to reveal their plant diversity, the prevailing life forms, the plant communities, and the main environmental drivers and phytogeographic patterns that shape these communities.
In the introductory chapter, the importance of rice ecosystems and the origin and history of rice cultivation are discussed. Further, I inform on the nature of these agroecosystems by providing details on the biology of the rice plant, the ecology and composition of rice environments, and the significance, diversity and control of rice weeds. The chapter ends with a closer look on the study area and the general description of applied methods.
The second and the third chapter give information on the composition of plant species and prevailing life forms on local paddies and bunds, respectively. The descriptions are complemented by recorded (and in the case of paddies also projected) levels of species richness to provide a comprehensive picture of the floristic diversity of the rice ecosystems in total, in each region, in uplands and lowlands, and in the two countries. The two studies identify the main rice weed communities in paddies and on bunds, and provide details on their differential species, geographic distribution, plant diversity, time of emergence during the crop cycle, as well as the abiotic conditions under which they occurred.
In the fourth chapter, the effects and relative importance of abiotic conditions, habitat type and surrounding landscapes on the plot-level plant diversity (alpha diversity) in the seven study regions are investigated and presented in a comparative overview. Another main objective of the study in this chapter is the quantification and visualization of the species turnovers (beta diversity) across sampling sites, between paddies and their bunds, and between regions.
The fifth chapter summarizes the major findings of the thesis to highlight the differences and similarities of bunds and paddies in terms of floristic diversity, the composition of species and life forms, the community variation along environmental gradients, and applied weed control measures and cultivation practices. I conclude that our results provide new insights into the composition and functioning of rice landscapes, and indicate remaining issues. The findings offer interesting opportunities for biodiversity conservation, ecological engineering approaches and the sustainable management of rice ecosystems.
[Aims] Bunds composed of plants with strong root systems have become one of the most important soil conservation measures for controlling soil erosion on sloping farmlands in the Three Gorges Reservoir area. In order to measure the friction characteristics of the root-soil interfaces to screen grasses for use in bunds to provide optimal soil bund protection.
[Methods] The influences of interface, soil moisture and vertical load were examined by using direct shear friction and pull-out friction tests in the study.
[Results] The results support the following conclusions. i) Friction characteristics were lower at interfaces in bulk soils than at root-soil interfaces. Direct friction characteristics were higher at the root-soil interface for goosegrass than other plants tested in this study. ii) The roots of grasses can substantially improve the soil shear strength under conditions of low (5%) and high soil moisture (25%). The relationships between friction characteristics and soil moisture can be described by binomial functions. iii) The constitutive relationship between the shear strength at the root-soil interface and vertical load can be described by a hyperbolic model that satisfies the Mohr-Coulomb criterion. The maximum pulling resistance was in the following order: goosegrass > barnyard grass > crabgrass.
[Conclusions] Among the three grasses tested, the goosegrass root system has a highest resistance to deformation capability for soil conservation. These results can be used as references for understanding and controlling the friction characteristics and collapse of soil bunds in the Three Gorges Reservoir area.
The restoration of planted vegetation contributes towards improving the habitat quality of waterbirds and enhancing the diversity of their communities. Thus, the success of projects attempting to restore aquatic vegetation could, in part, be quantified by evaluating the community structure of wintering waterbirds. Here, we evaluated the effect of wetland restoration (through planting aquatic vegetation) by comparing waterbird communities in restored versus unrestored areas over two wintering periods (2017–2018 and 2018–2019). Specifically, the use of aquatic vegetation by waterbirds was evaluated following restoration, and was compared against three control (unrestored) areas; namely, a Euryale ferox planting area, freshwater aquaculture area, and rice planting area. Twenty-nine species belonging to eleven families of waterbirds were recorded across the four habitats. Species richness and density of waterbirds in the restored aquatic vegetation area were significantly higher than those in the three control areas. The restored aquatic vegetation area had the highest absolute value of Temporal Beta-diversity Index (TBI), while species gains (C) were significantly greater than species losses (B). Additionally, there was a significant increase in the number of wintering waterbird species from three foraging guilds in the restored aquatic vegetation area during the wintering period of 2018–2019 compared to 2017–2018 (Granivore guild; Invertivore guild; Piscivore guild). The restoration of aquatic vegetation mainly caused the number of Anatidae species to increase, including ruddy shelduck (Tadorna ferruginea), common teal (Anas crecca), common mallard (Anas platyrhynchos), spot-billed duck (Anas poecilorhyncha), and common pochard (Aythya ferina). Submerged vegetation provides ducks with important food resources, such as seeds. And emerging vegetation facilitating the concealment of waterbirds. In conclusion, the artificial promotion of aquatic vegetation restoration at Shengjin Lake has contributed towards maintaining the structure of wintering waterbird communities.
Background: The ecosystems around, and plant composition in, paddy fields in Java are varied, owing to differences in climate, altitude, and traditional farming practice. This study examines the effects of different types of surrounding land use and vegetation on the plant diversity in paddy fields. Methods: We studied three upland (400-850 m asl) and three lowland areas (10-50 m asl) in the island of Java, Indonesia. Samples of vegetation were taken in fields and bunds (partition between paddy field plots) in two rice cultivation seasons from October 2011 through to June 2012, including the peak of rice cultivation in Java between October and February. We used Analysis of Variance Matrix Unbalanced to analyze the effects of area, complexity, location, and season on plant composition. Tukey's Honestly Significant Difference (HSD) test was performed to determine significant differences between groups in the sample. Results: We recorded 14 crop species and 221 non-cultivated plant species, of which 171 species occurred in paddy fields and 190 on bunds. Species numbers in upland areas were higher than in lowland areas. In fallows, twice as many species as in cultivated rice fields were found. The presence of semi-natural vegetation within short distance had no significant effect on plant species numbers in paddy fields. Multiple cropping and intercropping around paddy fields and on bunds had a marked effect on plant diversity. Conclusions: Differences in plant species numbers and composition between lowland and upland areas are more pronounced than the effects of local environmental complexity. To enhance high and varied plant diversity on the field and landscape scale, traditional multiple and intercropping systems should be supported.
Aims: Syntaxonomic classification is widely used for vegetation survey in Europe. The long history of its use has produced many concepts and names of vegetation units that need to be revised and integrated into a single classification system. Here we (1) present a new, global hierarchical syntaxonomic systems of alliances, orders, classes of the Braun-Blanquet syntaxonomy for vascular plant, bryophyte, lichen and algal communities; (2) characterize all accepted syntaxonomic concepts in ecological and geographical terms, (3) link all available synonyms to these concepts, and (4) provide a list of diagnostic species for all classes of European vegetation.
Location: Europe, Greenland, Arctic archipelagos, Canary Islands, Madeira, Azores and Cyprus.
Methods: We reviewed about 10 000 bibliographic sources to compile the syntaxonomic systems of classes, orders and alliances, and species lists characterizing all classes. All known syntaxonomic concepts were critically evaluated by experts and their names revised according to the International Code of Phytosociological Nomenclature.
Results: The newly compiled EuroVegChecklist is a syntaxonomic conspectus consists of systems of classes, orders, and alliances for the communities dominated by vascular plants (EVC1), bryophytes and lichens (EVC2), and algae (EVC3). EVC1 comprises 110 classes, 300 orders and 1088 alliances (with 4067 synonyms for all ranks); EVC2 27 classes, 53 orders and 137 alliances (with 410 synonyms for all ranks); EVC3 13 classes, 24 orders and 53 alliances (with 188 synonyms for all ranks). 13 289 diagnostic taxa were assigned to classes of EVC1, 2099 to classes of EVC2 and 346 to classes of EVC3. Information on each accepted syntaxonomic concept was made accessible through the software tool EuroVegBrowser. An expert system for an automatic identification of class membership based on the proportion of character species was also developed.
Conclusions: The Conspectus is the first comprehensive and critical account of syntaxa synthesizing more than 100 years of classification effort of European phytosociologists. It aims at stabilizing the nomenclature of the syntaxa and of classification concepts for practical uses such as calibration of habitat classification used by the European Union, standardization of terminology for environmental assessment studies, management and conservation of nature areas, landscape planning and education.
Rice field weed communities occurring in central Nepal are presented in this study. The research was focussed on the classification of segetal plant communities occurring in paddy fields, which had been poorly investigated from a geobotanical standpoint. In all, 108 phytosociological relevés were sampled, using the Braun-Blanquet method. The analyses classified the vegetation into 9 communities, including 7 associations and one subassociation. Four new plant associations and one new subassociation were proposed: Elatinetum triandro-ambiguae, Mazo pumili-Lindernietum ciliatae, Mazo pumili-Lindernietum ciliatae caesulietosum axillaris, Rotaletum rotundifoliae and Ammanietum pygmeae. Due to species composition and habitat preferences all phytocoenoses were included into the Oryzetea sativae class and Ludwigion hyssopifolio-octovalvis alliance. As in other rice field phytocoenoses, the main discrimination factors for the plots are depth of water, soil trophy and species richness. The altitudinal distribution also has a significant influence and separates the Rotaletum rotundifoliae and Elatinetum triandro-ambiguae associations. The study shows that anthropogenic rice fields can harbour relatively rich rush and water vegetation. More than 80 species were noted in the vegetation plots. Several of them are considered to be extremely rare and have been recorded on the world Red List.
Habitat management needs comprehensive perspectives, considering multiple ecosystem services at local and landscape scales. Stakeholder involvement with participatory research and development programmes for farmers is an essential part of it. Currently, ecological engineering by habitat management and participatory programmes and mass media campaigns are developed to counteract the adverse effects of ongoing intensification of rice production in Southeast Asia. These schemes often suggest the establishment of flower strips. Flower strips are a common measure to promote biodiversity and ecosystem service conservation in industrialised countries, since they aesthetically enrich production landscapes and provide supplementary food resources and shelter for natural enemies and pollinators.
The study presents the results of geobotanical investigations conducted in rice fields in southern Thailand in 2013. It is focussed on the classification of plant communities poorly investigated from a geobotanical standpoint. Altogether 125 phytosociological relevés were collected, using the Braun-Blanquet method. We noted more than 100 species in the vegetation plots, including many rare ones. We classified the vegetation into seven communities, including six associations. Five associations are proposed as new: Nymphaeetum nouchali, Fimbristylido miliaceae-Sphenocleetum zeylanicae, Ischaemo rugosi-Cyperetum pulcherrimi, Pentapeto phoeniceae-Aeschynomenetum indicae and Marsileetum minutae. The distinctiveness in species composition compared to other Oryzetea sativae phytocoenoses justifies a new alliance: Ludwigion hyssopifolio-octovalvidis. The main discrimination factors for the data set were water depth and species richness. The study reveals that rice paddy fields are inhabited by a variety of littoral and aquatic vegetation types. In particular, non-intensively cultivated rice fields hold a diverse hydrophilous flora, especially taxa typical for mud or littoral habitats.
The weed flora associated with field crop of rice in five governorates in the Nile Delta was studied. The weed association comprised 71 species related to 28 families (23 dicot families, five monocot families). The recorded species formed of 28 monocot species (39.4%), 42 dicot species (59.2%), and only one pteridophyte (1.4%). By using TWINSPAN technique the recorded weeds of 25 stands are grouped into six weed clusters. The weed clusters are superimposed on DCA axes 1 and 2 with respective eigene values of 1.00 and 0.964. The ordination plane shows that weed clusters are clearly separated along DCA-axis 2. These clusters are named after the dominant species as follows: Aster squamatus, Corchorus olitorius, Echinochloa crusgalli - Echinochloa colona, Amaranthus hybridus - Amaranthus viridis, Ammannia baccifera - Abutilon theophrasti and Ammannia attenuata - Anagallis arvensis. The therophytes represent 57.8% of the life form spectrum, while perennials represent 42.2%.
This paper presents some phytosociological data on the weed vegetation of rice fields in North Korea (D.P.R.K.). Only the association Sagittario-Monochorietum vaginalis Miyawaki 1960, described and known from the territory of Japan and South Korea, was found in all localities in the studied area. The variability of this community and the geographically induced differences exhibited by it in North Korea are reflected in the newly described syntaxa classified at subassociation level: S.-M. najadetosum gramineae, S.-M. limnophiletosum sessili-florae, and S.-M. sagittarietosum aginashi. Comparison with phytosociological relevés of this community from Japan and South Korea is included. One hundred and eleven relevés were analysed and the results clearly confirmed the phytogeographical differentiation of North Korean communities.
LEGATO stands for 'Land-use intensity and Ecological Engineering - Assessment Tools for risks and Opportunities in irrigated rice based production systems' and aims to advance long-term sustainable development of irrigated rice landscapes, against risks arising from multiple aspects of global change. The overall objective is the elaboration and testing of generally applicable principles within the frarne of ecological engineering - an ernerging discipline, concerned with design, monitoring and construction of ecosystems. Ecological engineering aims at developing strategies to maximize the ecosystem services through exploiting natural regulation mechanisms instead of suppressing them. A core component of this research project, which is part of the framework programme 'fona - Research for Sustainability', is to create the knowledge and decision-making base necessary for sustainable land management and also to provide the corresponding action strategies, technologies and systems solutions.
Question: How do traditional management practices of field margins maintain the biodiversity of native grassland species?
Location: Semi-natural grassland on the field margins of traditional and consolidated agricultural fields on Awaji Island, central Japan.
Methods: The distance to the nearest traditional field margin to the study sites was determined because the traditional field was considered as a seed source of native vegetation to the semi-natural grasslands under study. We selected field margins in consolidated fields of different ages and distances from seed sources. Indicator species for both field types were sought. Regression analysis and detrended correspondence analysis (DCA) were used to determine the effect of spatial and temporal distances on the species composition of native vegetation.
Results: Species richness differed significantly between the margin of traditional and consolidated fields. We identified significant indicator species of traditional fields, but not of consolidated fields. In consolidated fields, species richness increased significantly with age and decreased significantly with increasing distance to the source. At younger sites, species richness decreased faster with distance to the source because of strong negative correlation, but not at older sites. DCA ordination plots similarly indicated that similarities of vegetation composition in consolidated and traditional fields decreased with distance, and the effect of distance decreased with age.
Conclusions: The species composition of the grassland margins of consolidated field was more similar to the margins of traditional fields if the consolidated fields were older, and/or closer to traditional fields. This pattern suggests that dispersal may play a role in the establishment of species on field margins.
In mountainous areas of northern Vietnam, upland rice remains a crop of major importance, but yields are extremely low and variable. An iterative, multi-scale agronomic diagnosis, based on analysis of variability in farmers’ fields, was conducted in a village selected for being representative of biophysical conditions in Bac Kan Province. This diagnosis focussed on interactions between factors and processes, and aimed to identify major constraints to rice production in order to develop alternatives to the traditional slash-and-burn systems.
Variability between fields in rice yield was explained primarily by slashed forest type (5 classes were identified) and number of years of cultivation. Within fields, rice yield variability was largely explained by soil structure (porosity, compaction, bulk density) and partly by soil chemical characteristics. All these factors are, at different scales, indicators of soil regeneration/degradation status. Forest and soil regeneration is limited by short fallow duration (decreasing in the present context of rapidly increasing population pressure) and by intensive buffalo grazing. Soil degradation is caused by erosion after forests are slashed and burned. As a result, poor soil structure and shallow rooting (limited by physical and chemical soil conditions) lead to very poor water use efficiency. In addition, weed infestation is a major constraint to upland rice production in these conditions.
As a consequence, for improvement of (or design of alternatives to) these systems, research priority should be given to development of techniques or systems that increase water use efficiency and facilitate weed control. Until soils have been rehabilitated and protected, and weeds controlled, “classical” research on topics such as fertilisers or varieties will bring hardly any improvement in the traditional systems.
Rice is the staple food crop for about 50% of the world's population. It is grown mainly under two ecosystems, known as upland and lowland. Lowland rice contributes about 76% of the global rice production. The anaerobic soil environment created by flood irrigation of lowland rice brings several chemical changes in the rice rhizosphere that may influence growth and development and consequently yield. The main changes that occur in flooded or waterlogged rice soils are decreases in oxidation–reduction or redox potential and increases in iron (Fe2+) and manganese (Mn2+) concentrations because of the reductions of Fe3+ to Fe2+ and Mn4+ to Mn2+. The pH of acidic soils increased and alkaline soils decreased because of flooding. Other results are the reduction of nitrate (NO3 −) and nitrogen dioxide (NO2 −) to dinitrogen (N2) and nitrous oxide (N2O); reduction of sulfate (SO4 2−) to sulfide (S2−); reduction of carbon dioxide (CO2) to methane (CH4); improvement in the concentration and availability of phosphorus (P), calcium (Ca), magnesium (Mg), Fe, Mn, molybdenum (Mo), and silicon (Si); and decrease in concentration and availability of zinc (Zn), copper (Cu), and sulfur (S). Uptake of nitrogen (N) may increase if properly managed or applied in the reduced soil layer. The chemical changes occur because of physical reactions between the soil and water and also because of biological activities of anaerobic microorganisms. The magnitude of these chemical changes is determined by soil type, soil organic-matter content, soil fertility, cultivars, and microbial activities. The exclusion of oxygen (O2) from the flooded soils is accompanied by an increase of other gases (CO2, CH4, and H2), produced largely through processes of microbial respiration. The knowledge of the chemistry of lowland rice soils is important for fertility management and maximizing rice yield. This review discusses physical, biological, and chemical changes in flooded or lowland rice soils.
Background: The rapid decline of semi-natural grasslands in Japan threatens many relic and endemic plant species. There is insufficient knowledge on how the impacts of land-use changes and management of grasslands have been affecting grassland ecosystems and what conservation measures may be taken to conserve as much of the existing plant diversity as possible.Aim: We assessed the existing management regimes for their suitability for conserving Red Data Book (RDB) species.Methods: We conducted our study in four districts of Kushima, Kyushu, south-west Japan, with different land-use histories. We compared species richness, plant density and abundance in six grassland types: regularly burnt, regularly mown, paddy levee, roadside, landslip and wetland communities in a total of 289 1 m x 1 m quadrats, recorded in172 grassland patches. Species richness plant density and abundance were analysed with special reference to RDB species under different land use history.Results: Species richness of grasslands did not differ across different land use histories, yet our analysis showed that the reduced area of grasslands markedly affected the density of RDB species. Grassland types differed in their ability to support RDB species: regularly burnt grasslands were the richest in RDB species and poorest in alien species, followed by regularly mown grasslands, paddy levees, landslip, wetland and roadside communities.Conclusions: Traditional management regimes, such as regular burning or mowing of grasslands have the best potential for conserving RDB species, and thus should be part of conservation management practices of semi-natural grasslands.
Biodiversity relevant to pest management of tropical irrigated rice pests is discussed in terms of variation within rice plants, rice fields, groups of rice fields and rice associated ecosystems. It is concluded that, in the unique cropping conditions and stable water supply of tropical irrigated rice, the manipulation of a relatively few manageable components of diversity can confer stability such that pests are mostly kept at levels which do not justify the use of insecticides. The justification for, and supplementary use of, insecticides needs to be radically reassessed. There is no evidence that a natural control-based approach, as recommended in this review, is incompatible with farmer practicability or with future developments in rice production technologoy, except perhaps the possible mechanization-driven increase in field size which would decrease bund area. In contrast, the insecticide-based approach is not only harmful to natural controls but is costly and mostly demands impracticable decision making by farmers on need-based use. -from Authors
Plant communities of trampled soil dominated by plants characterized by the C4-assimilation syndrome were investigated in Europe. These species, belonging to genera such as Chamaesyce, Amaranthus, Eleusine, Eragrostis and Setaria, are thermophilous, late-germinating, prostrate herbs or grasses. The centre of their distribution is in the (Sub)Tropics. A syntaxonomic revision of the phytosociological material from Europe (incl. the Macaronesian Archipelago) revealed three alliances: the Euphorbion prostratae from Spain, the Polycarpo-Eleusinion indicae from Italy, and Slovenian and Croatian Istria, and the Eragrostio-Polygonion arenastri from temperate regions of Europe. The latter two syntaxa are described as new. All three alliances belong to the order Eragrostietalia (class Stellarietea mediae). Vicarious (ecologically analogous) communities occur also in southern Africa, eastern Asia and North America. The communities studied in the present paper are considered to be an impoverished form of highly diversified trampled plant communities typical of (sub)tropical areas.
A syntaxonomic study of trampled plant communities in North Korea is presented. Analytic and synthetic methods of the Braun‐Blanquet approach together with a numeric‐syntaxonomical analysis (cluster analysis and principal coordinate analysis ordination) were employed. With the exception of the Bryo‐Saginetum japonicae , all the associations, such as the Artemisio asiaticae‐Plantaginetum asiaticae, Plantagini depressae‐Polygonetum avicularis, Polygono avicularis‐Potentilletum costatae, Eragrostio multicaulis‐Plantaginetum depressae, Euphorbio maculatae‐Centipedetum minimae, Digitario pectiniformis‐Eleusinetum indicae and Setario viridis‐Chlorisetum virgatae , are described for the first time. Some communities also include a number of subassociations. Trampled communities are found along edges of paths and in cracks among paving stones. Soils vary from loamy to sandy and skeletal.
A phenomenon of seasonality in expression of ruderal communities was observed in North Korea. It is assumed that this seasonality is controlled by pattern of precipitation showing distinct climatic seasons (e.g. pre‐monsoon and post‐monsoon periods). The ruderal vegetation seasonality is supposed to become more pronounced towards tropical regions. Several mesophilous or slightly hygrophilous European species occur frequently in North Korean trampled communities including Chenopodium glaucum, C. ficifolium and Potentilla supina. Their occurrence in trampled habitats is hypothesized as being related to high air humidity and associated wet climate.
Aims: The knowledge of rice weed communities, their diversity, composition, dynamics and distribution is still
inadequate. We present information on the plant diversity of rice fields in major Southeast Asian centres of rice cultivation, the prevailing life forms, the plant communities, the main environmental drivers, and phytogeographic patterns that shape these communities. Study area: Seven different regions of Vietnam and the Philippines, including lowland and mountain areas (0–1390 m a.s.l.). Methods: Altogether 115 vegetation relevés using the Braun-Blanquet method were recorded during wet and dry seasons between 2013 and 2015. Soil samples were collected and farmers of surveyed rice fields were interviewed. Vegetation surveys were designed to detect possible effects of soil properties, climate, altitude, geographic location, landscape heterogeneity, seasonality, management and intensity of cultivation, and structural parameters on the paddy vegetation. Hierarchical cluster analysis UPGMA was applied and NMDS ordinations were performed to visualize differences in plant community composition along the different gradients. Results: We found 113 vascular plant species, with annual hydrophytes and therophytes being the prevailing life forms. Sixty of the recorded species appear to be globally rare. We revealed four clusters of plant communities which are explained mainly by soil acidity, crop height and temperature: Paspalum distichum-Hydrolea zeylanica community, Echinochloa crus-galli community, Rotala indica-Monochoria vaginalis community and Fimbristylis littoralis-Leptochloa chinensis community. The two latter communities were further classified into regional subunits. Conclusions: We conclude that the composition of weed communities provides valuable information on environmental and biogeographical conditions of the local rice landscapes, and that it is probably the most applicable and reliable indicator of management intensity.
The soils are fundamental to our existence, delivering water and nutrients to plants, that feed us. But they are in many ways in danger and their conservation is therefore a most important focus for science, governments and society as a whole.
A team of world recognised researchers have prepared this first English edition based on the 16th European edition.
• The precusors and the processes of soil development
• The physical, biological and chemical properties of soils
• Nutrients and Polluntants
• The various soil classifications with the main focus on the World Reference Base for Soil Resources (WRB)
• The most important soils and soil landscapes of the world
• Soil Evaluation Techniques
• Basic Principles of Soil Conservation
Whoever works with soils needs this book.
Like in other high developed industrial countries in Japan not only the indigenous vegetationbut also the industrial anthropogenous vegetation is in a process of changing. In the rice fields the longtime stabilized associations lost a good deal of their characteristical elements. On the other side especially on disturbed industrial places, vigorous neophytes are spreading.
A field experiment was conducted on a clay-loam soil during the rainy (kharif) season of 1995 and 1996 at Maruteru, Andhra Pradesh, to evaluate the performance of some succulent weeds as green-leaf manure in rice (Oryza sativa L.) nurseries. Fertilization of nursery, irrespective of source, greatly improved the seedling height, production of leaves, biomass, root number, root length and seedling growth rate. Among the green-leaf manure weeds, maximum values of seedling parameters were noticed in Crotolaria verrucosa L.-treated plots which was on a par with Casia angustifolia Vahl and Calotropis gigantea (L.) R. Br. ex. Ait. green-leaf incorporation. The seedlings were shorter and had sparse and thin root system in Croton sparciflorus L.-treated plots. The legume weed (Crotolaria verrucosa)-treated plots yielded 2.15 times more seedling bundles (226) than unfertilized plots. Pulling the seedlings was easy and took short time when the nursery received either organic or chemical fertilization. Unfertilized seedlings and those received basal fertilization established very quickly in the main field than those where N was top-dressed before pulling in the nursery. Green leaf manuring irrespective of its source suppressed the weed-seed germination of Echinochloa glabresence. Highest grain yield (52.4 q/ha) was obtained in plots received Crotolaria verrucosa green-leaf manuring and it was at par with other green leaf weeds except Croton sparciflorus.
The influence of ground cover plants on the ecosystem service of weed seed predation by crickets (Orthoptera: Gryllidae) was evaluated on paddy field levees in Japan in 2010 and 2011. We compared the activity density of crickets and invertebrate seed predation on Lolium multiflorum, a non-native grass weed, among five vegetation types grown on paddy levees: the ground covers Eremochloa ophiuroides, Phyla canescens, Phlox subulata, and Zoysia japonica, and weedy vegetation dominated by Digitaria ciliaris. Camera recordings showed that crickets were the predominant invertebrate seed predators. Cricket density tended to be higher on levees with E. ophiuroides, Phyla canescens, and Phlox subulata [5.8–7.2 individuals/trap/day (individuals/trap/d) (2010); 5.4–7.6 individuals/trap/d (2011)] than in those with Z. japonica and weedy vegetation [1.0–2.2 individuals/trap/d (2010); 2.2–3.2 individuals/trap/d (2011)]. Invertebrate seed predation on levees with Phyla canescens and Phlox subulata tended to be relatively high in both years. These results suggest that E. ophiuroides, Phyla canescens, and Phlox subulata can increase cricket density, and that Phyla canescens and Phlox subulata, in particular, can stably enhance weed seed predation on paddy field levees.
Slash-and-burn rice production systems in the hilly areas of Laos have changed little over the past decades except for a reduction in the fallow period which has caused a tremendous increase in labor requirements for weed control. From 1950 to 1990, the population density increased from 7.6 to 17.6 persons/km(2), fallow periods decreased from 38 to 5 years, and weeding requirements increased from 1.9 to 3.9 weedings/rice crop. Because of high requirements for weeding, the return to labor is only 5 kg rice/labor day for slash-and-burn systems compared with 13 kg/day in lowland rice production. Soil organic C levels are declining fast, with losses of 5 t/ha observed during a single rice crop. Improvements of the living standard of the farm population, food security stabilization of upland agriculture, and increased rice production are the main objectives of development agencies working in hilly areas. However, the options available are limited by the market opportunities and there is little chance that any of the technologies offered will be adopted on a significant scale. Hill farmers have a comparative advantage for livestock and timber production but generally lack the necessary resources to make long-term investments in either operation. Market, credit opportunities, and land tenure are key factors affecting the direction of future hill agriculture in Laos.
Jumla is one of the 75 districts in the midwestern hills of Nepal. Rice ( Oryza sativa L) cultivation in Jumla ranges from 2,400 to 3,050 m altitude, which is the highest elevation in the world. The highest elevation at 3,050 m is Chhumjul of Jumla, a record altitude, where rice is cultivated in Nepal. Jumli Marshi, a Japonica variety of indigenous rice, having cold tolerant gene, is probably cultivated since 1,300 years ago in Jumla in the bank of the Tila river. Improved rice varieties were tested in the Jumla valley by the Nepal Agricultural Research Council (NARC). In 2002, two improved rice varieties Chandannath-1 and Chandannath-3 were released for temperate region of Jumla and Karnali zone. Productivity of rice in Jumla is 1.7 mt/ha almost 40% lower than that of national average of 2.97 t/ha. Low productivity of rice is mainly due to the constraints of many biotic, abiotic and socio-economic factors. Food security in the food deficit region of the Karnali zone could be sustained by increasing rice productivity in the Jumla region where perennial irrigation is available round the year. Whole of the Jumla region is unique place with respect to rice cultivation in the highest altitude of the world. The practice of rice cultivation in Jumla could be a remarkable activity for boosting agro-tourism in the agrarian country like Nepal. Rice cultivation in Jumla is quite unique from the rice cultivation even in the same range of temperate region. Such a typical organic rice production system in the highest elevation of the world needs immediate attention of all institutions and authorities concerned to conserve it for the future generation as well. Jumla, the temperate region, is also affected by the impact of global warming thereby receding water level in the Tila river and its tributaries flowing in the Jumla valleys during rice growing season (March - October). Attempts have been made to document ethno-culture, socio-economic and cultural practices of rice cultivation in the highest elevation in the world. DOI: http://dx.doi.org/10.3126/ajn.v2i0.7519 Agronomy Journal of Nepal (Agron JN) Vol. 2: 2011 pp.31-41
Reis stellt für einen Großteil der Menschen die Hauptnahrungsgrundlage dar. Der in den letzten Jahrzehnten gestiegene Reisbedarf konnte durch eine Intensivierung des Reisanbaus gedeckt werden, was aber oft zu erheblichen Umweltschäden geführt hat. Das seit 2011 laufende interdisziplinäre LEGATO-Projekt hat eine Verbesserung der Nachhaltigkeit beim Reisanbau zum Ziel. Ein wichtiger Aspekt hierbei ist ein nachhaltiges Management des Silizium (Si)- Kreislaufs. Si erhöht die Resistenz der Reispflanze gegen Krankheitserreger, steigert die Effizienz von NPK-Düngern und kann die Aufnahme von toxischen Metallen verringern. In diesem Artikel stellen wir die Untersuchungsregionen des LEGATO-Projekts vor (Klima, Geologie, Böden, landwirtschaftliche Praktiken), zeigen Konzentrationen von pflanzenverfügbarem Si (Sipa) in den Reisböden (Ap + Arp-Horizonte) und diskutieren Faktoren, welche Unterschiede der Konzentrationen zwischen den Regionen steuern. Das Sipa wurde mittels Extraktion mit Natrium-Acetat-Lösung bestimmt. Die Ergebnisse zeigen, dass die Sipa-Konzentrationen in philippinischen Böden deutlich höher liegen als in vietnamesischen Böden (141-322 vs. 20-51 mg Si kg−1). Dies ist durch Unterschiede der geo-/pedologischen Bedingungen zu erklären. Die hohen Konzentrationen in philippinischen Böden entstehen durch die Freisetzung großer Mengen an mobilem Si während der Verwitterung vulkanischer Gesteine, die in der geologisch jüngeren Geschichte gebildet wurden. Auch die Landnutzung kann die Sipa-Konzentrationen in Oberböden beeinflussen. Die Konzentrationen in philippinischen Reisböden sind höher als die in Böden unter anderer Landnutzung (z.B. Wald, Gemüseanbau). In einigen vietnamesischen Reisfeldern könnte ein Si-Mangel den Reisertrag limitieren. Viele vietnamesische Bauern exportieren Reisstroh nach der Ernte und entziehen dem Kreislauf dadurch eine möglicherweise wichtige Quelle von Sipa. Wir werden deshalb als Nächstes untersuchen, ob man durch eine Änderung dieser Praktiken die Si-Versorgung der Reispflanzen verbessern kann.
Wild Edible Herbs in Paddy Fields and Their Sale in a Mixture in Houaphan Province, the Lao People’s Democratic Republic. Multiple wild edible herbs coexist in paddy fields under the agricultural practices used for growing rice. Paddy field vegetation was surveyed and the rural population’s perceptions and use of wild edible herbs were investigated in the northern Lao People’s Democratic Republic. A total of 115 wild herbaceous species were observed in the paddy fields of two villages; 52 species grew in fields, 95 on levees, and 63 on banks. Of these, 25 species were locally used, and 22 were sold as a mixture at the Xamneua market, with species composition varying by availability and season. The total number of edible greens increased during the summer season when available vegetables were scarce. Marsilea quadrifolia L. (Marsileaceae), the most abundant in the field and in the market, as well as Centella asiatica (L.) Urb. (Apiaceae), Eryngium foetidum L. (Apiaceae), Spilanthes oleracea L. (Asteraceae), and Monochoria hastata (L.) Solms (Pontederiaceae) were the most popular wild herbs sold. Wild edible herbs are called “phak”, which is also used to indicate cultivated vegetables, and clearly distinguishes them from the inedible herbs referred to as “nya.” Two methods are employed to gather wild edible herbs: some plants are uprooted as a way of thinning individuals, and other plants have only their young leaves picked so that they can be harvested repeatedly. Gathering and selling wild edible herbs was mainly conducted by women and children for whom it was a source of cash income. Thus, the relationships that exist between people and the wild plants they maintain as part of their farming activities can be considered an indicator of paddy field agrodiversity.
QuestionHow are the patterns of species richness and composition in marginal semi-natural grassland habitats maintained by different disturbance regimes characterized by location and agricultural management practice?LocationA terraced paddy field landscape in southeastern Niigata Prefecture, Japan (37°06′N, 138°49′E).Methods
We recorded species occurrence within five 1 m × 1 m quadrats at each survey site from four different habitat types: paddy levees (Levee); slopes between paddies and farm roads (i.e. entrance slopes of paddy fields; Slope_Road); slopes between paddies (Slope_Paddy); and slopes between paddies and adjacent woodlands (Slope_Woodland). We compared species composition among the habitat types using non-metric multidimensional scaling (NMDS). We then classified plant functional groups (PFG) based on four response traits: growth form, life span, plant height and flowering season, and compared richness patterns of PFG among the habitat types using analysis of covariance.ResultsThe estimated total richness was over 220 species in Slope_Paddy, Slope_Woodland, and Slope_Road, including more than 35 grassland species in each habitat type. Species composition at Levee habitat was significantly different from that at the other three habitat types as revealed by the NMDS axis 1 scores. The NMDS axis 2 scores for Levee and Slope_Road habitats were significantly different from those for Slope_Paddy and Slope_Woodland habitats. Species richness patterns along with the ten PFGs investigated in this study were also significantly different among the habitat types. Levee and Slope_Road habitats were characterized by a number of annual species, whereas tall perennial forbs, especially pteridophytes, characterized Slope_Paddy and Slope_Woodland habitats.Conclusions
While some species occurred in all four habitats, habitat specialists characterized by specific PFG responded to different disturbance regimes in each habitat type. The four types of marginal semi-natural grassland play different roles as habitats for a variety of herbaceous species, including typical semi-natural grassland species. These habitats make up the complex landscape mosaics of terraced paddy fields and contribute to the overall biodiversity of these landscapes at the regional scale.
This study assessed the cultural and weed management factors influencing the weed communities of Hungarian rice fields. Hungary is situated at the northern limit of rice production with a history of about 300 years of rice culture. We surveyed the weed flora and 25 background variables in 100 active rice fields. Using a minimal adequate model containing 11 terms, 48.5% of the total variation in weed species data could be explained. The net effects of nine variables on species composition were significant. Crop cover was found to be the most important explanatory variable, which was followed by the herbicides penoxsulam and azimsulfuron, tillage depth, phosphorous and potassium fertilisers, years after last rotation, water depth in May, sowing type, pendimethalin and water conductivity. Filamentous algae, as the most abundant group of weeds, were positively associated with deep tillage, deep water and surface sowing. Echinochloa crus-galli, one of the most troublesome grass weeds, was associated with low rice cover, shallow water and later years after crop rotation, while weedy rice favoured high crop cover, deep water and soil sowing. These findings can be used to design improved weed management strategies. The occurrence of red list species and charophytes in diverse micro-mosaic patterns deserves attention from a conservation perspective, as well. The maintenance of these unique charophyte communities can be facilitated by shallow tillage without soil inversion.
A country uncommonly rich in plants, animals, and natural habitats, the Socialist Republic of Vietnam shelters a significant portion of the world’s biological diversity, including rare and unique organisms and an unusual mixture of tropical and temperate species. This book is the first comprehensive account of Vietnam’s natural history in English. Illustrated with maps, photographs, and thirty-five original watercolor illustrations, the book offers a complete tour of the country’s plants and animals along with a full discussion of the factors shaping their evolution and distribution.
Separate chapters focus on northern, central, and southern Vietnam, regions that encompass tropics, subtropics, mountains, lowlands, wetland and river regions, delta and coastal areas, and offshore islands. The authors provide detailed descriptions of key natural areas to visit, where a traveler might explore limestone caves or glimpse some of the country’s twenty-seven monkey and ape species and more than 850 bird species. The book also explores the long history of humans in the country, including the impact of the Vietnam-American War on plants and animals, and describes current efforts to conserve Vietnam’s complex, fragile, and widely threatened biodiversity.
: The study present results of geobotanical investigations conducted in rice fi elds in the central Pamir Alai Mts (Tajikistan, Middle Asia), mainly within Syr-Daria, Pyandzh, Zeravshan, Kafi rnigan, Khanaka and Surkhandaria river valleys in the years 2009–2011. The researches were focused on classifi cation of plant communities developing within this poorly investigated area. Habitat conditions were checked including conductometry, pH reaction, temperature, depth of water and, for several plots, also soil structure. Altogether 114 phytosociological relevés using the Braun-Blanquet method were sampled. The analyses classifi ed the vegetation into 28 communities including 24 associations. Five new plant associations and two new names for the syntaxa were proposed. The main discrimination factors for the data set are depth of water and altitude. Water reaction and conductometry have a minor role. The study shows that anthropogenic rice fi elds could harbour a relatively rich rush and water vegetation. Particularly extensively cultivated puddles could serve as a suitable habitat for many hygrophilous plants. We found more than 120 species in vegetation plots, including some which are rare and have not been recorded until now in this part of Middle Asia. Moreover several alien species that we found were established in rice fi eld vegetation, e.g. Bidens frondsa or Symphyotrichum graminifolium.
The influence of the type of field boundary vegetation on sorghum plant bug [Stenotus rubrovittatus (Matsumura)] abundance was studied in 36 rice fields at three study sites in Chiba Prefecture, Japan. To survey the field abundance of the species, we used traps baited with a synthetic attractant pheromone. We also surveyed field boundary vegetation located within a 100-m radius from each trap. A two-way indicator species analysis (TWINSPAN) of the vegetation types in 785 boundaries of study fields as well as surrounding fields resulted in five groups. A generalized linear mixed model (GLMM) was built to investigate the effects of field boundary vegetation types on the abundance of S. rubrovittatus. Intensive mowing in June of immediate and surrounding rice field boundaries containing flowering host plants of S. rubrovittatus, such as Lolium multiflorum Lam. and other poaceous plants, is the key to reducing the total abundance of S. rubrovittatus. The result implies that an area-wide pest management strategy should be developed based on food source preferences and habitat specificity of the agricultural pest species.
本研究では, 除草剤を用いない雑草管理体系が水田とその畦畔植生に及ぼす影響を明らかにするため, 隣接する除草剤施用の水田ならびに畦畔と比較検討した。調査は千葉県匝瑳市 (旧八日市場市) の谷津田で行った。年4回の植生調査の結果, 総出現種数は101種で, 水田内で確認された種が50種, そのうち非除草剤水田では39種, 除草剤施用水田では25種が確認できた。一方, 非除草剤畦畔で52種, 除草剤施用畦畔で60種が確認された。(1) TWINSPANによる植生分類の結果, いずれの雑草管理手法においてもその植生は概ね水田と畦畔に分かれ, また水田の植生には季節変動が認められた。(2) 非除草剤水田の平均出現種数は除草剤施用水田と比べて有意に多くなった。(3) 非除草剤畦畔では伝統的畦畔によくみられるチガヤ, スイバ, オオジシバリなど多年草が多く出現した。一方, 除草剤施用畦畔ではスギナ, ヨモギ, ハルジオンの他, メヒシバ, スズメノテッポウ, カヤツリグサなどの一年草が多くなった。
Weed vegetation in rice-fields and the associated irrigation system in Ferrara Province (northern Italy) is described. The main weed communities are: Oryzeto-Cyperetum difformis, Spirodelo-Lemnetum minoris, Najadetum minoris, Potamogetono-Najadetum marinae and Ceratophylletum demersi. Fragmentary halophyte communities also occur on the canal sides.Data on climate and the environment are also reported.
Die Ackerunkrautgesellschaften aller japanischen Inseln wurden durch zahlreiche Geländeaufnahmen studiert. Diese ziemlich einheitlichen Aufnahmen ergaben nach wiederholten Tabellenbear-beitungen folgende fünf Assoziationen:
The effects of two contrasting farming systems on the floristic composition and vegetation structure that make up the Yatoda
landscape were investigated. The experimental field was set up at Yatoda in a hilly district in Zhejiang province, China.
Vegetation surveys were done in summer 2002 and 2003. Vegetation was divided into four types based on species composition:
grassland formerly used for rice cultivation (G), rice paddy (P), ridge way (R), and levee slope (S). In P, R, and S plots,
each vegetation type was subdivided according to the different farming systems. Under the traditional system, there were a
number of species, and the diversity index values were greater than those under the conventional system. Blyxa echinosperma and Marsilea quadrifolia, which are threatened species in Japan, were seen in the paddy field under the traditional farming system.
In Japan, rice paddies have acted as substitute habitats for pond-breeding frogs. However, frog populations are declining due to the loss of habitat and environmental changes in rice paddy areas. Frogs need both aquatic and terrestrial habitats to complete their life history; in rice paddy areas, levees that surround rice paddies provide terrestrial habitats for basking, foraging, and shelter from predators. Studying microhabitat use at levees is important to elucidating the ecological roles of levees and to properly managing them to support frog populations. In this study, we conducted surveys in lowland modernized rice paddy areas in Shiga Prefecture in which a common species, Hyla japonica, and an endangered species, Pelophylax porosa brevipoda, were found. We captured frogs at levees and recorded environmental factors related to levee vegetation, rice paddy conditions, and weather. We constructed generalized linear mixed models to examine the effects of environmental factors on juvenile and adult H. japonica and on small and large juveniles, females, and males of P. p. brevipoda. Our results showed distinct microhabitat uses at levees in different species, sexes, and body sizes. In general, abundance was high at levees with vegetation that provided shelter. The water depth in rice paddies negatively influenced juvenile H. japonica and large juvenile and small female P. p. brevipoda, and positively influenced small male P. p. brevipoda. The maintenance of a mosaic structure of levees was important not only to support frog populations but also to maintain frog diversity in the area.
Based upon a world-wide literature review and a database, which refers to 250 publications and documents about 8500 phytosociological relevés, the following questions are discussed: What are the common ecological parameters for temporary wetlands and which environmental conditions offer a niche for dwarf ephemerals? Which taxa have evolved and speciated within ephemeral wetland habitats? How do the relations between relief features, local hydrology and climatic conditions change in different parts of the world? Which global patterns in flora and vegetation do occur?The review is restricted to ephemeral freshwater ecosystems with the following two properties: Above-ground plant cover is seasonal, and the habitats are water-saturated or submerged only part of the year. For a better understanding of large-scale patterns, the results of studies about small-scale zonation, variability in time (phenology and year-to-year dynamics), ecophysiology and life strategies are briefly reported. Finally, conservation aspects and trends of floristic globalization are considered.Three habitat types can be distinguished according to relief, hydrology and climate:1. Seasonal pools: They occur in semi-arid and subhumid climates at both sides of the Tropic of Cancer. The catchment areas are local or the ponds are purely rainwater systems.2. Amphibic shorelines of permanent ponds, lakes and rivers: They concentrate in perhumid extratropical temperate zones and in orotropical climates. Along allochthonous rivers with extended catchments and with seasonal flood pulse, large temporary floodplains also occur in semi-arid regions.3. Ephemeral flush habitats: In the perhumid tropics and in the subhumid subtropics, ephemeral wetlands are linked to runoff-habitats like the slopes of inselbergs and rock outcrops and to interflow habitats along intermittent streams.The distribution of some keystone taxa reflects the present climatic differentiation of the globe and to some extent also historical events (palaeogeography, speciation processes). Myosurus for example is linked to extratropical regions, Lilaeopsis to the New World and the Southern Hemisphere, Limnophila and Rhamphicarpa to the Palaeotropical region. Vicariance patterns are a common phenomenon. Examples can be seen in Isoetes, Marsilea, Ophioglossum, Juncus (sections Tenageia, Ozophyllum and Caespitosi), Limosella, Crassula (section Helophytum), Bacopa, Hydrocotyle, Eriocaulon and Xyris. These genera speciated within this environment and evolved habitat equivalent species. The reduced size and the spatial isolation of the habitat reduce gene flow and favour allopatric speciation. The variability in time and small-scale ecological gradients stimulate sympatric speciation by temporal separation of the populations. Niche-equivalent taxa replace each other in different parts of the world. The niche of dwarf ephemeroid annuals is occupied by Centrolepidaceae in the Australian region, by Restionaceae in the Capensis, by Eriocaulaceae in the Australian region and East Asia, by Juncaceae in the holarctic kingdom, by Orcuttieae in the Californian phytogeographical sector, and by Cyperaceae, Crassulaceae, Gentianaceae, Elatinaceae and Apiaceae in all floristic kingdoms. Other predominant life forms are herbaceous perennials with the isoetid syndrome, geophytic ferns (Ophioglossum, Marsilea), carnivorous plants from the families Lentibulariaceae and Droseraceae, and poikilohydric vascular plants with the xyroid syndrome. The latter occur in the Tropics, with Xyridaceae (pantropical), Velloziaceae (neotropical region), Afrotrilepis, Craterostigma, Lindernia, Chamaegigas (palaeotropical region), Trilepis (neotropical region) and Borya (Australian region). (to be continued in the full text).
Up t o now, only a few authors have published relevès or synoptic tables of the segetal vegetation of rainfed fields of the West African Sahelian and Sudanian zone. Only one of them ( Ataholo 2001) has presented a rich relevé material, but no higher syntaxa were validly described. In this paper, we have compiled all relevés available in order to present a syntaxonomic overview on the segetal vegetation mentioned above. The segetal vegetation of rain-fed arable fields in West Africa floristically is clearly differentiated into the Ipomoeo eriocarpae-Commelinetalia benghalensis and the Mitracarpo hirti-Alysicarpetalia ovalifolii. The first order represents the weed vegetation of house fields and gardens which are highly fertilized with organic waste. The second order comprises the segetal vegetation of fields that are only weakly fertilized or do not even receive any fertilizer. While the first order unifi es only one alliance, within the second order three alliances can be identifi ed. The Tridaco procumbentis-Schwenckion americanae contains mainly South Sudanian communities, the Spermacocion chaetocephalae is a North Sudanian alliance and the Jaquemontion tamnifoliae has a Sahelian character. The species composition of these units not only mirrors the geographic position or the extra zonal situation, but also the length of the fallow period and the soil conditions. Many species that are abund ant in the South Sudanian zone only grow on the most humid fields of the Sahelian zone. The same is true for Guinean species occurring in the Sudanian zone. Floristically, the Sudanian segetal vegetation strongly differs from that of the weed communities described so far from other tropical regions. But there are obvious affi liations to the annual ruderal vegetation of Sudanian West Africa.