首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 113 毫秒
1.
A key assumption in many homegarden studies is that homegardens are ecologically and socio-economically sustainable due to their species diversity. The precise relation between diversity and sustainability is still heavily debated, however. A basic question is how diversity in homegardens can best be characterized in view of the various dimensions of species diversity and their variation in time and space. This paper assesses different types of species diversity in the homegardens of Sidama region of southern Ethiopia. In a survey of crop species in 144 homegardens a total of 78 cultivated crop species (excluding trees) belonging to 10 functional groups were recorded; there were on average 16 crop species and 8 functional groups per farm. Within homegardens, plots differ in species composition and crop diversity. Four types of homegarden systems are distinguished differing in both type and area-share of dominant species, relative orientation at subsistence or cash production and overall crop diversity. The gradual replacement of enset by maize and of coffee by more financially attractive cash crops khat and pineapple causes a decrease in overall crop diversity. Our data demonstrate that it is incorrect to consider homegardens as generic systems with a uniform distribution of species diversity: important within and between homegarden variation exists. Ecological and socio-economic sustainability is not just related to species diversity per se, but rather to more specific features such as presence of keystone species and diversity in functional species groups. Socio-economic sustainability in terms of adjustment to socio-economic change implies dynamics in species diversity.  相似文献   

2.
Diversity of trees and shrubs in agricultural systems contributes to provision of wood and non-wood products, and protects the environment, thereby, enhancing socioeconomic and ecological sustainability of the systems. This study characterizes the diversity, density and composition of trees in the agroforestry homegardens of Sidama Zone, Southern Ethiopia, and analyses physical and socioeconomic factors influencing diversity and composition of trees in the systems. A total of 144 homegardens were surveyed from 12 sites. In total, 120 species of trees and shrubs were recorded of which, 74.2 % were native to the area. The mean number of tree species per farm was 21. Density of trees varied between sites with mean values ranging from 86 to 1,082, and the overall average was 475 trees ha?1. Four different crop-based enset (Enset ventricosum (Welw.) Cheesman)-coffee homegarden types were recognized and they differed not only in the composition of major crops but also in the diversity, density and composition of trees. The composition, diversity and density of trees is influenced by physical and socioeconomic factors. The major physical factors were geographical distance between sites and differences in altitude of farms. The most important socioeconomic factors were farm size and access to roads. Tree species richness and density increased with farm size. Increased road access facilitated marketing opportunities to agricultural products including trees, and lead to a decline in the basic components of the system, enset, coffee and trees. In the road-access sites, the native trees have also been largely replaced with fast growing exotic species, mainly eucalypts. The decrease in diversity of trees and perennial components of the system, and its gradual replacement with new cash and annual food crops could jeopardize the integrity and complexity of the system, which has been responsible for its sustenance.  相似文献   

3.
Although homegardens are most often suggested as the refuges for biodiversity in human-dominated landscapes, how the surrounding landscape and socioeconomic characteristics affect this diversity in the tropics has received little research attention. Hence, this study has examined how these factors affect woody species diversity in homegardens of northeast Ethiopia. Three landscapes which are similar in agroecology were selected and in total 54 households were used for both a survey and a woody species inventory in respondents’ homegardens. The homegardens were stratified based on their locations in relation to crop fields and natural vegetation using satellite images from Google Earth. The variation in Shannon–Wiener diversity index among homegardens and the effect of the socioeconomic factors including household wealth status, homegarden area and the households’ types of uses of woody plants on species diversity were analyzed using one-way ANOVA. Altogether 53 woody plant species belonging to 35 botanical families were identified. Survey results indicated that the woody species diversity was higher in homegardens situated close to crop land as compared with the diversity in homegardens close to natural vegetation. Higher woody species diversity was recorded in homegardens which are larger in area and where the households’ types of uses of woody plants is higher. Moreover, the woody species diversity was found to be higher in homegardens of the high and medium income households when compared with that of poor households. Overall, results suggest that the concurrent ecological and socioeconomic studies are needed to design conservation strategy and policy for plant biodiversity in agricultural landscapes.  相似文献   

4.
Although the homegarden systems in the tropics are claimed to sustain basic community needs without environmental deterioration, the ecological rationalities behind the harmony between the humans, homegardens, and the environment are not well understood. Four study sites (Sukhothai, Srisatchanalai, Ayudhaya, and Nonthaburi) representing the four Thai eras in the Chao Phraya Basin were selected for studying these rationalities. The size and physical stature of the homegardens, their plant association and community features, physical environmental factors, nutrient and soil fertility parameters, and cultivation practices were studied. The major factor that determines species selection in homegardens is the utilization of the products, while the various practices within the homegardens are determined by such factors as the species, the system, and the environment. All homegardens had four vertical stratifications, with physical structures almost similar to that of dry dipterocarp forest, but with lower height for each layer, lower diversity of plants, and sparser crown layer. The analysis also shows a high possible utilization efficiency for space, light, water and nutrients in the soil in the homegardens. Shannon-Wiener's indices of species diversity of the homegardens were close to those of dipterocarp forest. The homegardens are in-situ reservoirs for biodiversity at genetic-, species-, and ecological levels. There was no complete harvesting from these homegardens. This practice ensured minimal nutrient export from the systems, while high amounts and diversity of litter biomass should contribute to high efficiency of nutrient cycling. Futhermore, phosphorus availability could be better in homegardens. The homegardens had more favorable microenvironment with lower soil and atmospheric temperature and higher relative humidity than outside. There has been no single incident of a pest outbreak at a threatening level. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

5.
An analogue approach to analysing the traditional homegardens of Keralavis-à-vis natural climax ecosystems is adopted. The traditional homegarden is apparently a climax ecosystem, where ecological succession is consciously manipulated by human beings. High intensity of vertical and horizontal space use, the highly dynamic chronological structure and the capacity to perform essential ecological processes make this ecosystem relatively sustainable. Homegardens in Kerala effectively serve as human ecosystems with their low input demand, staggered supply of outputs, and enhancement of habitat quality. However, recent trends in agrarian structure and the high market orientation exert pressures on the homegarden, and its sustainability as a human ecosystem is in question.This joint paper is based on part of the research conducted by Darley Jose for the degree of M.Sc. (Natural Resource Management) at the Agricultural University of Norway under the guidance of N. Shanmugaratnam.  相似文献   

6.
The choice of plant species, their arrangement and management varies between and within tropical homegardens in the same community. Relationships between agroecological and socioeconomic characteristics of 20 homegardens were examined at Masaya, Nicaragua. Variables analyzed were micro-zonation (area allocation to specific uses and management), plant use and diversity, occupation, labor investment, and product, benefit and income generation. Data was collected through surveys, participatory mapping, plant inventories, direct observation and interviews. Ten different micro-zones and nine plant uses were identified. Fruit trees, shaded coffee and ornamentals were the most important zones. Plant diversity was high, with a sample total of 324 species. Homegardens were an important occupation, with average labor investments of 32.6 h family–1 week–1. Families obtained at least 40 different plant products from homegardens, as well as the benefit of space for working and socializing. Six homegarden types were identified using a cluster analysis based on biophysical variables. Types reflected the relationship between income generation and the number and types of zones and plant species present. Labor inputs were high considering the small size of the homegardens (average size 3,240 m2), although no clear relationships between labor investment and plant and zone type or number were observed. Homegarden management strategies of plant selection and zonation were affected both by family choices and external forces. Although dependence on homegardens may vary according to specific conditions at a given time, they seem to be a consistent, flexible resource used to meet a diversity of needs. The methodological approach used in this paper may be appropriate for the study of other traditional agroecosystems since it includes both biophysical and socioeconomic variables, essential for understanding these complex systems.  相似文献   

7.
Household and homegarden characteristics in southwestern Bangladesh   总被引：1，自引：0，他引：1  
Homegardens around the world often exhibit remarkable variation in composition and structure depending on the physiographic and climatic conditions of the area and a wide variety of household characteristics. This research investigated whether households’ contextual attributes have a quantitative and predictable relationship with homegarden vegetation structure from a total of 402 randomly selected households in southwestern Bangladesh. The central analytical tool to test the relationship between household characteristics and the homegarden vegetation structure was multiple regression. The moderate to low regression R 2 values revealed that most household characteristics were not strong predictors of homegarden vegetation structure. Despite the weak explanatory power of the majority household characteristics, time spent and homestead size had the strongest relationship with species richness and income in a homegarden. Households being the main source of labor for a majority of households suggest that outside labor shortage would not influence homegarden vegetation structure. We suggest that women’s active participation in homegardening activities to reduce gender inequality in the family which will perhaps result in more diverse and economically viable homegarden. However, increasing population density and the concomitant fragmentation of landholdings to homesteads may create opportunity for homegarden promotion in Bangladesh. Our results of decreased species richness in the homegarden with improved roads and proximity to market support the general hypothesis of subsistence homegardens and did not reinforce the general fears of gradual decline in species richness due to a market economy. Household characteristics had no influence on the presence of IUCN Red Listed species in the homegarden, except for gender and education of the household head. However, most homegardeners were unaware about the status of red listed species, suggesting that occurrence of red listed species in homegardens was by chance. Thus, efforts to improve awareness and to save and conserve rare species from extirpation are needed.  相似文献   

8.
The cultivation of different plants in homegardens for self-sufficiency has a long tradition in Cuba, but knowledge about homegardens in Cuba is small. To analyse this more deeply, cultivated plants of 31 homegardens were surveyed in three villages in eastern Cuba in 2001. Two of the study villages were located in a humid area with an annual precipitation of about 2200 mm. The third village was situated in a semiarid area with about 450 mm precipitation. The plants studied in the homegardens included those for human consumption such as fruits, vegetables, tubers and cereals as well as spices and medicinal plants. In total, 101 different plant species were found with an average number of 18 to 24 species per homegarden for the three villages. A broad range of species was found in all villages, because irrigation is used under semiarid conditions, which lead to a relative high similarity in species composition between the villages. But, also differences due to the climatic situation became evident, particularly with the medicinal plants. In general, homegarden production provided a broad and diverse basis for self-sufficiency of the households. Although homegarden production showed to be only a small source of income, it is particularly important because of low-paid outside work and minimal food provision of the state.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

9.
Homegardens of Bukoba are a traditional multi-storey agroforestry farming system based on mixed cropping and livestock keeping. Major crops are banana (Musa spp.) grown for food and coffee (Coffea canephora var.robusta) for cash. Livestock keeping is dominated by cattle. Over the last few decades the farming system in Bukoba has been pervaded by a host of constraints ranging from biological to socio-economic. Consequently farm productivity has declined and so has the economic welfare of the people in the area. A questionnaire survey was conducted in 1991 to 72 households in Bukoba district to compare three potential farming systems: the rehabilitation of the homegardens, the cultivation of two annual crops namely maize and beans as intercrops and the continuation of the current non-rehabilitated homegardens. Results strongly support the rehabilitation of homegardens by use of cattle manure and proper crop and livestock husbandry practices. Rehabilitated homegarden has the highest net present value and is not very sensitive to changes in prices of inputs and outputs.  相似文献   

10.
2002年1月至6月对孟加拉涝原地区两个不同的宗教部落(印度教和穆斯林教)的传统家园森林进行了探索性研究，包括印度教和穆斯林教社团对树种(乔木和灌木)的偏爱度、类似性、造林材料及来源、植树地点和间距。研究发现Mangifera indica作为乔木树种，Ocimum sanctum作为灌木树种为印度教社团最喜爱的树种；Artocarpus heterophyllus和Lawsonia inermis分别为穆斯林社团最喜爱乔木树种和灌木树种。两中不同宗教社团选择乔木数种的相同性为86．57％，灌木树种为78．48％。两个宗教部落使用种子和苗木作为造林材料最多。乔木树种的造林材料主要来自家园(39％)灌木树种主要来自自然界(40％)。表3参27。  相似文献   

11.
A vegetation survey of traditional homegardens in four regions (South western, North western, Eastern and Central northern) in Bangladesh was conducted with reference to marginal (> 0.002–0.08 ha), small (> 0.08–0.14 ha), medium (> 0.14–0.20 ha) and large (> 0.20 ha) farm categories. Eighty homegardens (five from each farm category in each of the four regions) were assessed in terms of perennial species. The floristic data were ordinated (DECORANA) with respect to homegarden categories based on size and region. Most species were planted in the border of the homegardens irrespective of farm size and region. Food and fruit producing species dominated near the living quarter and working areas and small plots of annual vegetables and crops separated this part of the garden from more distant parts favoured for timber species. Six vertical strata were recognised with higher plant density and species richness recorded in the lower three. In total ninety two perennial species were recorded for the set of 80 homegardens surveyed. From gardens in the South western region 67 species were recorded. Corresponding figures were 56 for the Central northern region, 54 for the Eastern region and 46 for the North western region. Within regions there were significant differences in species richness associated with farm size, and within each homegarden size category there were significant differences among regions. Diversity was highest among food and fruit producing species, followed by the timber species. The ordination showed a distinction between the North western and the other regions due to a combination of lower species richness in the North western region homegardens and several species exclusive to the region. Floristic differences led to less marked but nevertheless important differences among the other regions, also.  相似文献   

12.
Tropical and subtropical homegardens often show variation in floristic and structure depending on household characteristics. This research investigated how the household characteristics could influence homegarden vegetation characteristics for 50 randomly selected households in Kalaroa Upazila of Satkhira District, Bangladesh. The central analytical tool to test the relationships between household and homegarden characteristics was multiple linear regression. The results revealed that household landholdings, income, homestead size, and time spent for homegardening were strong predictors of homegarden vegetation characteristics. Economic conditions of the household, experience of the household head, and homegarden investment explained 48 % of the total plant diversity. The combined effects of all significant variables explained about 57 % of the variability in species richness. If homegarden species composition and structure receive attention by concerned authorities, the development of economically viable and ecologically sustainable homegardens can be one aim of the policy guidelines with regard to natural resource conservation and sustainable management basis in Bangladesh could act as a principal source for employment of women in rural Bangladesh.  相似文献   

13.
A questionnaire survey was conducted among 72 randomly selected households in Bukoba district, Tanzania from August to November 1991. The objective of the study was to identify the major constraints to increased productivity in homegardens and farmers response to these constraints. Declining of homegarden productivity seems to have been influenced by the gradual decline of soil fertility mainly as a result of decrease in cattle population, the serious outbreak of banana weevils, nematodes and later Panama disease, fragmentation of homegardens due to population growth and lack of cash. As a result, homegardens can no longer subsist farm families for the most part of the year. The actual decline in banana yield is 66% over the last 20 years. Incomes are too low to support modest investment to improve productivity in homegardens. Farmers' responses to these problems have been out-migration, a shift towards cultivation of root crops, planting of beer banana and decrease in homegarden management intensity. These responses however are likely to offer only short term and partial solutions.  相似文献   

14.
We examined structural and functional changes in the homegardens of Sukapura village, located in the upper Citarum Watershed of Indonesia, in relation to the increasing commercialization of agriculture. Our main purpose was to examine the structure and function of these homegardens during the rapid economic development of this area and the ecological, social, and economic implications of changes. A standard vegetation survey was used to describe the compositional and structural patterns of vegetation in the sampled homegardens, and interviewed 94 randomly selected respondents to help us understand the functions of their homegardens. The results suggest that commercialization in the agricultural sector has changed the structural patterns and functions of these homegardens. Plant diversity in commercialized (intensively managed) homegardens has decreased owing to the use of monocultures. The change from subsistence towards commercial farming has been accompanied by decreased plant diversity, higher risks, higher external inputs, increased instability, and reduced social equitability. The specific needs and preferences of the owners and market pressures were the main factors that triggered the development of intensive agriculture in the study area, leading to increased commercialization of homegardens.  相似文献   

15.
Indigenous Agroforestry Systems in Amazonia: From Prehistory to Today   总被引：1，自引：0，他引：1  
Understanding the historical development of indigenous systems will provide valuable information for the design of ecologically desirable agroforestry production systems. Such studies have been relatively few, especially in Amazonia. The agroforestry systems in Amazonia follow a trail that begins with the arrival of the first hunter-gatherers in prehistoric times, followed by the domestication of plants for agriculture, the development of complex societies rich in material culture, the decimation of these societies by European diseases, warfare, and slavery, the introduction of exotic species, and finally, the present-day scenario of widespread deforestation, in which agroforestry is ascribed a potential role as an alternative land use. Despite the upheavals which occurred in colonial times, greatly reducing the population of native tribes, a review of anthropological and ethnobiological literature from recent decades indicates that a great variety of indigenous agroforestry practices still exist, ranging from deliberate planting of trees in homegardens and fields to the management of volunteer seedlings of both cultivated and wild species. These practices result in various configurations of agroforestry systems, such as homegardens, tree/crop combinations in fields, orchards of mixed fruit trees, and enriched fallows. Together they constitute a stock of knowledge developed over millenia, and represent technologies that evolved along with the domestication of native forest species and their incorporation into food production systems. This knowledge is the basis for the principal agroforestry practice employed by farmers in Amazonia today, the homegarden, and has potential to contribute to the development of other agroforestry systems.  相似文献   

16.
Societal processes of rural change and globalization may change homegardens and their contribution to the conservation of agrobiodiversity, particularly of species occurring naturally in regional vegetation. The best way to determine if this occurs is through longitudinal studies. We conducted such a study, inventorying tree species in a sample of 38 homegardens in 2009, 2012 and 2015. The homegardens were located in the subregions of mountain slopes, fluvial plains and coastal plains in the tropical lowlands of Tabasco, Mexico. We analysed changes in species richness by geographic origin, species richness and species composition in each inventory. We identified 169 tree species in the three inventories, of which 74.6% were native or neotropical and 25.4% introduced. Of the 140 species recorded in 2009, 88% remained in 2015, whereas 12% had been replaced and nine additional species had arrived. Mean species richness increased between 2009 and 2015 (P = 0.03) and between 2012 and 2015 (P = 0.001). Increases resulted from increased mean neotropical (P = 0.01) and introduced (P = 0.01) species richness, and constant native species richness. Differences in species composition between the three subregions in 2009 persisted in 2012 and 2015 (P < 0.001 in all years). These results show how the highly dynamic character of homegardens combines with the renewal and persistence of their agrobiodiversity, and underpins the continued relevance of homegarden for agrobiodiversity conservation and livelihoods in tropical lowlands amidst rural change and globalization.  相似文献   

17.
The shortened fallow period in traditional slash and burn agriculture of the Maya of Quintana Roo, Mexico, has reduced soil fertility, crop yields, biodiversity, and mature forest vegetation. Studies have shown that agroforests that mimic local ecosystem processes can be used to provide for the farmers' well-being while protecting and preserving forest resources and biodiversity. The objective of this investigation was to identify, describe, and evaluate Mayan crop plants that could be used as analog species in agroforest design. We used participant observation, interviews with farmers, and field measurements to collect information on the social, agricultural, and ecological aspects of the plants. We identified five horizontal and one vertical strata in mature homegardens: the herbaceous stratum, the low shrub stratum, the tall shrub stratum, the fruit tree stratum, the timber tree stratum, and the viny stratum. We categorized 77 forbes, shrubs, and vines identified for their temporal and spatial placement in an agroforest. The plants evaluated can be placed in one of the four developmental stages of an agroforest: the herbaceous stage, and the shrub stage, the fruit tree stage, and the timber tree stage. By using the identified plants and the analog hypothesis, we can design an agroecological system that provides for the farmers' needs, and efficiently utilizes the resources on-site for the production of food, timber, medicinal plants, and nontimber products in a manner that protects the natural resource base of the region. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

18.
Multipurpose trees, the integral components of homegardens, contribute significantly to the closed nutrient cycling processes and sustainability of the ecosystem. Although, the litter production and probable nutrient returns via litter in homegardens have been documented, quantification and characterization of the decomposition and bioelement release from the litter have received relatively little scientific attention. The objective of the present study is to explore the litter dynamics of six locally important multipurpose trees (Mangifera indica L., Artocarpus heterophyllus Lamk., Anacardium occidentale L., Ailanthus triphysa Dennst., Artocarpus hirsutus L. and Swietenia macrophylla L.), in an agroforestry homegarden in Southern Kerala, India. Litterfall and nutrient additions in the six species ranged from 383 to 868 g m−2 yr−1, nitrogen, 6.4 to 8.8, phosphorus, 0.17 to 0.42 and potassium, 1.1 to 2.8 g m−2 yr−1. The annual litter output in the homegarden was 425 kg with A. hirsutus, M. indica, A. heterophyllus and A. occidentale recording significantly higher litter and nutrient additions. Leaf litter decay studies revealed A. heterophyllus and A. occidentale to be the most labile litter species and S. macrophylla the most recalcitrant. The decay rate coefficients varied significantly among the species. Foliage decomposition rates related to the initial chemical composition of the litter revealed best correlation with lignin. NPK release was almost complete by the end of decay in all species inspite of the initial phases of accumulation observed for nitrogen and phosphorus. Two-way analysis of variance test revealed significant differences in the contents of the three elements as a function of species and time elapsed. Macronutrients were released in the order K>N/P. The higher rates of decay and nutrient turnover in M. indica, A. heterophyllus and A. occidentale foliage indicated the potential of using these species’ litter as nutrient inputs in agriculture while A. triphysa, A. hirsutus and S. macrophylla perform better as organic mulches taking a longer time for decay and hence nutrient release.  相似文献   

19.
The Yucatán Peninsula of México has shallow soils and receives low amounts of precipitation, and has therefore low agricultural potential. Lacking large-scale irrigation from rivers and adequate rainfall, the indigenous Maya groups maintain agricultural productivity by adapting a variety of practices. Multistrata homegardens, one of their agricultural systems, have provided goods for trade, sale and personal consumption for many centuries. Nevertheless, an understanding of the controlling biological factors and interactions within these systems can lead to yield improvements. Photosynthetic rates, water use and litter production for a variety of species have been studied in these gardens to determine how Maya management impacts resource flow, productivity and diversity. When irrigated, diurnal photosynthetic rates nearly doubled for Manilkara zapota and water use increased two fold for M. zapota and Cordia dodecandra. Total litter production in traditional homegardens varied from 1,000 to 4,000 kg ha−1 yr−1 and ten arboreal species were found to contribute more than 33% of total litterfall biomass. Nutrient concentrations in the leaves of the predominant species were analyzed; Meliococcusbijugatus and Spondias purpurea were found to contribute the largest quantities of N, P and C. Our research indicates that species and structural diversity are critical to sustainability of homegardens, allowing efficient use and transfer of carbon, nutrients and water. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

20.
The major components of the process of production in the homegardens of a tropical Mexican community are described and analyzed. Specifically, management tasks, means of production, and the amount, quality and temporal distribution of the products are discussed. The ecological, technological and productive advantages generally attributed to this kind of agroforestry cropping system in comparison to monocultures were also found in the homegardens of Balzapote. However, the area presently managed under this system is restricted, and its local and regional impact is thus very limited. Based on the detailed analysis of the functional differences in 8 homegardens and the socioeconomic roles they play in the economic organization of peasant families, the possible expansion of homegardens in the Mexican tropics is discussed.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号