Conservation of forest biodiversity and ecosystem properties in a pastoral landscape of the Ecuadorian Andes

High Andean cloud forests are home to a diversity of unique wildlife and are important providers of ecosystem services to people in the Andean regions. The extent of these cloud forests has been widely reduced through conversion to pasture for livestock, which threatens the forests’ ability to support biodiversity and provide ecosystem services. This paper explores whether impacts on woody plant biodiversity and four ecosystem properties (woody plant species richness, juvenile timber tree abundance, soil organic matter content and soil moisture) from converting forest to pasture can be mitigated if some woody forest vegetation is maintained within pastures. Woody vegetation in pastures was found to conserve those woody plant species that are more tolerant to exposure and grazing, but conservation of the high montane cloud forest community required areas of forest from which livestock were restricted. The sampled sites clustered according to woody plant species cover; these clusters represented a gradient from pasture with patches of shrubs to mature forest. Clusters differed in both woody plant species richness and number of juvenile timber trees whereas soil organic matter and soil moisture were observed to be similar among all clusters. This suggests that the different habitats may have some equivalent ecosystem properties. We conclude that the presence of woody vegetation in pastures may reduce some of the impacts of converting forest to pasture, but should not be considered a substitute for protecting large areas of forest, which are essential for maintaining woody plant species diversity in high Andean cloud forest.     

Ecological rationalities of the traditional homegarden system in the Chao Phraya Basin, Thailand

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.     

Plant-soil biodiversity relationships and nutrient retention in agricultural riparian zones of the Sacramento Valley,California

Forested riparian buffers in California historically supported high levels of biodiversity, but human activities have degraded these ecosystems over much of their former range. This study examined plant communities, belowground biodiversity and indicators of multiple ecosystem functions of riparian areas across an agricultural landscape in the Sacramento Valley of California, USA. Plant, nematode and soil microbial communities and soil physical and chemical properties were studied along 50-m transects at 20 sites that represented the different land use, soil and vegetation types in the landscape. Riparian zones supported greater plant diversity and nearly twice as much total carbon (C) per hectare compared to adjacent land managed for agricultural uses, but had generally lower soil microbial and nematode diversity and abundance. When woody plant communities were present in the riparian zone, plant diversity and species richness were higher, and soil nitrate and plant-available phosphorus levels were lower. Belowground diversity and community structure, however, appeared to depend more on plant productivity (as inferred by vegetation cover) than plant diversity or species richness. Greater plant species richness, nematode food web structure, total microbial biomass, woody C storage and lower soil nitrate and phosphorus loading were correlated with higher visual riparian health assessment scores, offering the possibility of managing these riparian habitats to provide multiple ecosystem functions.     

Interdisciplinary analysis of homegardens in Nicaragua: micro- zonation, plant use and socioeconomic importance

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.     

Woody Plants Diversity and Possession,and Their Future Prospects in Small-Scale Tree and Shrub Growing in Agricultural Landscapes in Central Highlands of Ethiopia

Woody plants diversity and possession in small-scale tree and shrub growing practices among farmers of central highland Ethiopia were assessed by using a complete census of the trees and shrubs existing on farmers’ lands. The future prospects of diversity and possession of woody plants in the agricultural landscapes were also investigated by using the farmers’ species preferences and seedling demands as indicators. Comparisons were made across wealth classes, proximity clusters to a nearby state forest and land uses. It was found that 27 tree and 21 shrub species exist on lands of the studied households. With increasing wealth status of the households, the tree and shrub species richnesses increased. Tree and shrub species richnesses were highest in boundary plantings and homesteads respectively. Small-scale woodlots had the highest number of tree stems while homesteads contained the highest number of shrub stems. The number of tree stems a household possesses is strongly influenced by distance from the state forest, family size, educational level of the household head and number of iron-roofed houses owned. And, the shrub stems possession is significantly influenced by wealth status, distance from the state forest, land holding size, family size, livestock holding, age of wife and possession of off-farm income sources. The species preference analysis and seedling demand computations indicated that the woody species diversity is less likely to change in the future because there is no difference between the currently existing species and the preferred ones. Nonetheless, the number of tree and shrub stems on the farmers’ holdings could increase if the seedling demands of the preferred woody species are met.     

Spatial and temporal variation in crop diversity in agroforestry homegardens of southern Ethiopia

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.     

株洲市城郊植物多样性调查研究

植物多样性是生物多样性的重要层面,园林绿化是人工群落组成部分。保护生物多样性,模拟地带性人工植被,才能实现园林绿化低成本、高效益、高生产力、高生物量的总体目标。因此,对城郊天然林调查有其必要性。调查结果表明：株洲城郊有种子植物约500种（不含栽培植物）,隶属73科,187属,其中木本植物193种,草本植物300余种。过渡特征明显,特有成分丰富,观赏植物资源众多,外来种是株洲城郊生物多样性重要成分。其结果为人工模拟天然植被与保护生物多样性提供科学依据。     

Plant use and management in homegardens and swiddens: evidence from the Bolivian Amazon

Amazonian plant management is perhaps nowhere as intense as in homegardens and swiddens. A quantitative ethnobotanical study was conducted in Indigenous Territory and National Park Isiboro-Sécure, Bolivia, to investigate plant use and management in homegardens and swiddens by local Yuracaré and Trinitario ethnic groups. Ethnobotanical data of plants were obtained from 11 Yuracaré and 11 Trinitario participants through semistructured interviews. A total of 151 different cultivated or tolerated species was recorded, accounting for 21% of all inventoried plants considered useful to local Yuracarés and Trinitarios. The local use value of managed plants is almost twice that of wild plants. Managed plants score particularly higher than wild plants for medicinal, food and material applications. Most managed plants are herbs, followed by trees and shrubs. Nevertheless, managed trees have significantly higher overall use values than all other life forms. Managed trees tend to be particularly more appreciated as sources of food and materials, whereas herbaceous plants generally have a higher therapeutic value. Our results support observations made in literature that moderately humanized landscapes, and homegardens and swiddens in particular, are an important source of food and healing for forest people. Although people generally start managing plants in homegardens and swiddens because of their perceived usefulness, they are also favourable locations to experiment with the usefulness of (managed or wild) plants prevailing there. This particularly accounts for medicinal plants and it is argued that the use of managed plants in traditional medicine relates to (1) the high intensity of contact with theses species, and (2) their chemical defence strategy. To conclude, a number of policy recommendations are presented.     

Quercus calliprinos regrowth advantage under grazing in Mediterranean maquis and its management implications

The post disturbance natural succession of the Mediterranean maquis, which turns open and species-rich landscapes into dense, closed stands of sclerophyllous woody vegetation is a principal threat to plant and animal diversity. Therefore, in the absence of traditional agricultural disturbance, active management regimes that include cutting and grazing are proposed to preserve biodiversity. The Mediterranean woody vegetation in Israel is strongly dominated by one species - the evergreen sclerophyllous Quercus calliprinos (Kermes oak). We hypothesized that under cutting and grazing, the evergreen Q. calliprinos has a relative regrowth advantage over other competing tree species. Here we examined the effect of grazing and the effect of tree structural traits on the regrowth after clear cutting of all trees in our study plots at Mt. Meron LTER site, Israel. All trees were removed from five blocks of 2000 m² and each block was divided into two plots, five of which were exposed to grazing livestock while five were wire-fenced and ungrazed. The regrowth rate of Q. calliprinos under grazing was higher than that of all other tree species suggesting that in the long-term, under such a conservation management regime, the dominance of the evergreen sclerophyllous Q. calliprinos over the deciduous tree species will increase and consequently will decrease plant and animal diversity. Therefore, we conclude that to protect landscape and species diversity in Mediterranean ecosystems dominated by evergreen oaks, when cutting and grazing are applied, special care must be paid to trees that are more negatively affected by such treatment.     

Traditional agroforestry systems and biodiversity conservation in Benin (West Africa)

In the past, the conservation of biodiversity has been mostly understood in terms of the management of protected areas and natural forests, ignoring the possible role of farm areas and the ways through which rural communities have promoted biodiversity in their subsistence agricultural production systems. The present study focused on the floristic diversity within traditional agroforestry parkland systems around the Pendjari Biosphere Reserve in Benin and showed the diversity of tree species in the area as well as socio-economic factors which affect the practice of this farming system. We used questionnaires and interviewed a total of 118 households to collect data. Respondents were interviewed on their farms and during the interview; we inventoried the number of tree on the farm and determined the farm size. Twenty-one tree species belonging to 14 botanical families were recorded during the surveys and the average stand density of the woody component of farmlands was 7.97 ± 5.43 stems/ha. A number of both native and exotic tree species occurred in the parkland agroforestry systems with dominance of indigenous tree species. Species richness varied with the size of household where households with small land holding conserve more tree species in their field than households with large land holdings. 64% of households surveyed were making deliberate efforts to plant tree species on their farmlands. The most important reasons which determined household ambitions to conserve woody species on farmland were tree products contribution to food and medicine. Results also showed that respondents who noticed that trees were decreasing in the wild conserve more tree species on their farmlands. This research highlights the role of traditional agroforestry practices to support tree species richness and provides evidence of the farms’ role as biodiversity reservoirs.     

Dynamics of Homegarden Structure and Function in Kerala, India

Homegardens in Kerala have long been important multi-purpose agroforestry systems that combine ecological and socioeconomical sustainability. However, traditional homegardens are subject to different conversion processes linked to socioeconomic changes. These dynamics were studied in a survey of 30 homegardens. On the basis of a cluster analysis of tree/shrub species density and subsequent further grouping using homegarden size as additional characteristic, six homegarden types were differentiated. These were assessed regarding structural, functional, management and dynamics characteristics. Four development stages of homegardens were found along a gradient from traditional to modern homegardens. Fifty percent of the homegardens still displayed traditional features, whereas 33% incorporated modern practices. The process of modernisation includes a decrease of the tree/shrub diversity, a gradual concentration on a limited number of cash-crop species, an increase of ornamental plants, a gradual homogenization of homegarden structure and an increased use of external inputs. One homegarden was characterised as an adapted traditional homegarden combining multispecies composition and intensive management practices using internal inputs with commercial production. In comparison to modern homegardens, this homegarden type offers an example of an alternative development path in adapting homegardens to changing socioeconomic conditions. The study of structural and functional dynamics of homegardens offers the opportunity to understand the trends in socio-economic sustainability and how these relate to ecological sustainability.     

Initial vegetation recovery following a blowdown of a conifer plantation in monsoonal East Asia: Impacts of legacy retention, salvaging, site preparation, and weeding

All or a part of a sequence of forest practices (i.e., salvage logging, site preparation, planting crop trees, and weeding) has been implemented after natural disturbances for the rapid re-establishment of tree cover. Forest policies in Japan have recently changed from monocultural planting of coniferous crop trees to planting native broadleaved trees to restore forests and nurture local biodiversity following large windthrows. However, the effects of this new practice on preserving biodiversity, as well as the effects of legacy retention, have never been verified in Asia. Thus, the objective of our research was to compare the effects of legacy retention with plantation after salvaging on the initial stage of vegetation recovery in a blowdown area, specifically focusing on plant species diversity, the occurrence of alien species, and the composition of plant species. Following the analysis of our results, we finally describe appropriate practices to alter disturbed coniferous plantations to bring the species composition closer to that of the original natural mixed forests.A control (A, legacy retention) and three experimental treatment sites (B, salvage logged, site prepared, and Quercus crispula seedlings planted; C, same as B, but weeded once during the summer; and D, residual rows that emerged after establishing sites for planting) were prepared, and quadrats were set. Eleven indicators of the ground condition and the number of vascular plant species, including ferns, were quantified, and the number and abundance of residual and newly colonized plants of the main woody species were estimated.Our main findings were as follows: (1) in unsalvaged sites and residual rows, the diversity of plant species was poor, but a variety of plant species compositions were observed due to the heterogeneous conditions of the ground and ample residual plants; (2) in the planting site, many species appeared, but little variety of the species composition was observed due to the homogeneous condition of the ground and the destruction of residual plants; (3) a large number of alien species emerged in broad, unvegetated areas; (4) the impact of site preparation overwhelmed the impact of salvage logging on the initial recovery of plant species; and (5) to restore a natural mixed forest, a combination of legacy retention and plantation after salvaging would be the most appropriate.     

Effects of Household Characteristics on Homegarden Characteristics in Kalaroa Upazila,Satkhira District,Bangladesh

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.     

Vegetation community responses to different establishment regimes in loblolly pine (Pinus taeda) plantations in southern MS,USA

Management treatments involving multiple herbicide applications are standard procedure on most industrial pine plantation sites in the southern USA, raising concerns about biodiversity impairment. Management decisions impact not only plant communities but also the habitat potential they create for wildlife. We tested the effects of five intensities of stand establishment treatments on vegetation communities in loblolly pine plantations (n = 4) to age 5 in the Middle Coastal Plain (MCP) of Mississippi. Measurements were species richness, diversity, coverage, and community composition. Treatments were combinations of mechanical site preparation (MSP), chemical site preparation (CSP), and herbaceous weed control (HWC) both banded or broadcast for 1 or 2 years using the same herbicide mixtures. Tree richness and diversity were reduced by increasing treatment intensity; tree coverage, which included crop and non-crop trees, was less in moderate-intensity treatments. Vine richness and coverage were less in more intensive treatments, but 2 diversity indices differed on whether vine diversity was likewise affected. Richness and coverage of forbs and graminoids was lessened by broadcast HWC, with effects mostly limited to the year of application. Plant communities differed in all 5 years, with CSP acting as the primary factor for years 2–5. Early seral communities were favored by CSP, but broadcast HWC suppressed resulting herbaceous plants. Though CSP may somewhat reduce stand-level plant diversity, it may increase overall biodiversity within plantation-dominated landscapes by creating early succession plant communities that enhance wildlife habitat.     

Plant Resources of the Traditional Homegardens in Bangladesh

Abstract

A vegetation survey in four regions (Deltaic, Dryland, Hilly and Plain) in Bangladesh was conducted over a period of 10 months from July 1992 to April 1993. Eighty homegardens (20 from each of the four regions) were assessed in terms of composition, dominance and uses of the perennial species. In total ninety-two perennial species were recorded for the set of 80 homegardens surveyed. From gardens in the Deltaic region 67 species were recorded. Corresponding figures were 56 for the Plain region, 54 for the Hilly region and 46 for the Dryland region. Species composition pattern indicated higher proportion of food and fruit producing species and the first five dominant species with the highest relative importance values were the fruit trees. Eight major uses of the homegarden plants were recorded.     

Commercialization of homegardens in an Indonesian village: vegetation composition and functional changes

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.     

藏龙岛国家湿地公园植物多样性调查

通过对藏龙岛国家湿地公园的调查得知:共有维管束植物350种,隶属于105科271属,其中木本植物115种,草本植物235种,草本植物占优势;人工引种栽培植物87种,野生植物263种,以野生植物占优势;在科的组成上,以单属科和小型科为主,物种数最多的科为禾本科,有30属35种;属的分布以中、小型属分布为优势,是构成本地区植物多样性的重要组成类群,也是组成湿地植被的主要类群;湿地植被可划分为4个植被型组,7个植被型,32个群系。     

The effects of management and plant diversity on carbon storage in coffee agroforestry systems in Costa Rica

Agroforestry systems can mitigate greenhouse gas (GHG) emissions, conserve biodiversity and generate income. Whereas the provision of ecosystem services by agroforestry is well documented, the functional relationships between species composition, diversity and carbon (C)-storage remain uncertain. This study aimed to analyze the effects of management (conventional vs. organic), woody plant diversity and plant composition on aboveground and belowground C-storage in coffee agroforestry systems. It was expected that organic farms would store more C, and that an increase in plant diversity would enhance C-storage due to complementarity effects. Additionally, it was expected that steep slopes decrease C-storage as a result of topsoil erosion. Woody plants were identified on 1?ha plots within 14 coffee farms (7 conventional and 7 organic). C-stocks in trees, coffee plants and roots were estimated from allometric equations. C-stocks in litter and topsoil (0?C25?cm) were estimated by sampling. On average, farms stored 93?±?29?Mg?C?ha^?1. Soil organic carbon accounted for 69?% of total C. Total C-stocks were 43?% higher on organic farms than on conventional farms (P?<?0.05). Conventional and organic farms differed in vegetation structure, but not in species diversity. It was found that the combined effect of farm type, species richness, species composition and slope explained 83?% of the variation in total C-storage across all farms (P?<?0.001). Coffee agroforestry in general and organic farms in particular may contribute to GHG mitigation and biodiversity conservation in a synergistic manner which has implications for the effective allocation of resources for conservation and climate change mitigation strategies in the agricultural sector.