Plant community responses to a gradient of site preparation intensities in pine plantations in the Coastal Plain of North Carolina

Intensively managed loblolly pine (Pinus taeda) forests are common in the southeastern United States and offer opportunities for conservation of biologic diversity. Within intensively managed landscapes, stand establishment relies on combinations of mechanical and chemical site preparation and herbaceous weed control (HWC) to manage competing vegetation and increase pine production. However, few long-term studies have described relationships between intensity of stand establishment and effects on plant communities. Therefore, we examined effects of 6 treatments that varied in intensity via combinations of mechanical (wide spacing and strip shear or narrow spacing and roller chop) and chemical (application or no application) site preparation treatments with HWC (broadcast or banded) from 1 to 8 years after site preparation on plant communities in loblolly pine plantations (n = 6) in the Coastal Plain of North Carolina, USA. All treatments resulted in abundant and diverse plant communities. Chemical site preparation had short lived (?4 year) effects on the herbaceous community but long-term effects on woody plants and pine cover. Increasing management intensity by including broadcast HWC or roller chop/narrow spacing did not additively reduce woody vegetation cover or species richness. However, broadcast HWC reduced grass, vine, and forb cover in the first year post-treatment. Average Morista community similarity values ranged from 0.69 to 0.89 among treatments and plots receiving the same chemical site preparation contained the most similar plant communities. Banded HWC can be paired with wide spacing to maximize herbaceous plant growth important for many wildlife species, particularly in the first few years after site preparation. Site preparation techniques should be tailored to local site conditions, plant communities, and management objectives.     

Evidence for anthropic selection of the Sheanut tree (Vitellaria paradoxa)

The Sheanut tree (Vitellaria paradoxa Gaertn.), a multi-purpose species highly valued for the oil obtained from its seeds, is commonly maintained in the semi-arid parklands of sub-Saharan West Africa. An inventory in the West Gonja District, Northern Region, Ghana, revealed that on intensively farmed land this species constituted 79.7 ± 7.2% (Basal area = 2.19 ± 0.64 m² ha⁻¹) of the woody biomass, on low intensity farmland 84.2 ± 10.0% (2.16 ± 0.57 m² ha⁻¹) and only 10.2 ± 3.3% (0.92 ± 0.23 m² ha⁻¹) in unmanaged woodland, with similar environmental characteristics. No significant differences were found between total Sheanut tree densities on different land use intensities, although as a proportion of all trees surveyed, large trees were more common on farmed land. Participatory surveys revealed that these populations are a direct result of anthropic selection as local farmers eliminate unwanted woody species on farmland, leaving only those Sheanut trees that meet criteria based on spacing, size, growth, health, age and yield. Characteristics that could affect population dynamics during traditional management and harvesting including short viability seeds and cryptogeal germination are also discussed with reference to unconscious selection. Tree improvement is currently constrained, as true to type varieties are difficult to propagate. It is proposed that Sheanut trees on farmland are semi-domesticated having been subject to long-term anthropic selection during cycles of traditional fallow and crop cultivation. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effect of management and spatial characteristics on plant species richness of Castanea sativa Mill. woodlots in the NW Iberian Peninsula

This paper analyzes the effect of the spatial characteristics and intensity of land use on vascular plant species richness in Castanea (Chestnut) woodlots of the northwestern Iberian Peninsula included in the category “9260 Castanea sativa woodland” (Annex I, DC 92/43 European Community). Digital maps were used to characterize 30 woodlots for which land use intensity was estimated and all plants found were inventoried. The results show that woodlot shape and land use intensity have a significant effect on vascular plant richness and indicator species number. However, an analysis of the interaction between woodlot characteristics and land use intensity suggests that the response of vascular plant species to land use intensity does not exhibit a uniform pattern and that it is modulated by the shape of the woodlots. We conclude that restricting the use of these types of woods to traditional practices must be determined in keeping with the specific characteristics of each woodlot, since the moderate management of Castanea sativa woodlots of the northwest Iberian Peninsula may continue to play an important role to maintaining plant species diversity in this area.     

Understanding forest transition in the Philippines: main farm-level factors influencing smallholder’s capacity and intention to plant native timber trees

The ‘when, where and how’ of decisions by smallholder upland farmers to plant trees as part of their use of natural, human and capital resources needs to be understood if policy support is to result in actual recovery of tree cover as part of a ‘forest transition’ trajectory. In large parts of the Philippines the turning point may be close. Data on resource access and tree planting decisions were gathered from a household survey, with a total of 148 respondents in four rural communities in Leyte Province in Central Philippines. Data were analysed using logistic regression analysis. Household-level results reveal that the outcomes of the decision-making processes primarily depend on the availability of land and access to remaining forest resources rather than socio-cultural or economic factors. The total area of land and number of parcels managed by the household plus security of land tenure through ownership was found to have a statistically significant effect on farmers’ decision to plant native timber trees. Access to surrounding natural forest is negatively associated with farmer tree planting.     

论林木引种与森林可持续经营

森林是实现环境与发展相统一的关键和纽带,在实现国家可持续发展中具有不可替代的作用。外来树种是森林遗传资源的重要组成部分,具有一些乡土树种难以替代的优势。外来树种人工林可持续经营的核心问题是树种与种源的正确选择,为此,保存和丰富必要的基因资源就显得极为重要。外来树种具有一定程度的环境风险,但并没有人们想象的那样大。对当地生物多样性的影响有利有弊,关键是如何科学运作,包括确定合适的地域范围,与乡土树种的合理空间布局,以及如何使之在当地生态系统中形成密不可分的生物链。最危险的情况出现于因检疫不严而带来的病虫危害。     

Plant communities, species diversity, richness, and regeneration of a traditionally managed coastal forest, Kenya

The Kenyan coastal forests make up one of the World 25 Biodiversity Hotspots. They consist of over 140 fragments (the majority with areas less than 0.5 km²) of the once extensive Zanzibar-Inhambane lowland moist forest. The over 60 known Mijikenda sacred Kaya forests and groves scattered along the coastal hinterland form the greater part of this ecosystem. The forests are of biological and cultural significance, and this has been recognized nationally and internationally, with some now listed as World Heritage Sites. The forests are protected by councils of Kaya elders who regulate use of their resources. Increasing human population and subsequent rise in demand for forest products and land for settlement has put a strain on these relic forests. Farm encroachment and extraction of forest products in different Kaya forests have affected the vegetation ecology at varying levels. This study investigated the spatial species distribution, association and regeneration potential of commonly utilized plants in one of these traditionally managed ecosystems. A modified nested plot method was used to collect data in the field.Using TWINSPAN multivariate, and indicator species analysis, two plant communities (Asteranthe and Bridelia) and an undifferentiated vegetation type were identified. Species association in Asteranthe consisted largely of forest dependant species, with a significant presence of woody climbers. It was comprised of two sub-communities namely Manilkara and Scorodophloeos. In contrast the second plant community, Bridelia, was dominated by light demanding species. It comprised one sub-community (Catunaregam) and a seral stage (Keetia). The species diversity and richness was higher in the Asteranthe community compared to Bridelia. Some of the forest species commonly utilized by the local people were observed to regenerate both in open and closed forest habitats while others had seedling recruitment confined to closed forest.Despite some coastal forests showing physiognomic similarity, detailed study shows intra-variation linked to topography, exposition, type and intensity of human perturbation both currently and in the distant past. Clearly, vegetation patterns of coastal forests of eastern Africa change at fairly short intervals.Recruitment of forest specialists is likely to decline if closed forests are opened up by farm encroachment, however their less specialized counterparts can pioneer in re-colonization of disturbed sites if conservation is strengthened. There is need to invigorate traditional management systems of forests with cultural significance by recognizing and giving increased legal mandates to the local custodians.     

Establishment strategies for poplars,including mulch and plant types,on agricultural land in Sweden

Biomass from forestry is one of the largest components of Sweden’s renewable resources. Poplars are currently the highest producing tree species available and are therefore natural choices for biomass-oriented production. Growing poplars has been of most interest on agricultural land, but the knowledge and experience about their cultivation is still limited. Factors that have a large impact on the regeneration results are plant material, competing vegetation, browsing and damage caused by voles or climatic factors. Due to large establishment costs, there is a need to find methods to secure the establishment both biologically and economically. In this study the effect of plastic mulch in combination with three different plant types (short cuttings, long cuttings and rooted plants) were tested at three different sites. Five years after planting, the overall effect of mulch was an improved plant survival and growth. In most cases, long cuttings outperformed short cuttings and rooted plants. Clonal differences were present, indicating the importance of using plant material adapted to site conditions. All sites were heavily affected by browsing and during the experimental period 100% of the plants were damaged at some point. Planting poplars without fencing is therefore doubtful. Results from this study conclude that poplars can be established with success on agricultural land if proper measures are used depending on the site to be planted.     

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.     

Landscape-level effects of forest management on faunal diversity in bottomland hardwoods

Forest management activities potentially influence ecosystems at many spatial scales. For most forest systems, influences at the stand level have been most intensively studied and are best understood. Management impacts at the larger, landscape scale are poorly understood and many hypotheses regarding landscape-level effects remain untested. This lack of knowledge is particularly acute in bottomland hardwood forest (BLH) ecosystems. Most hypotheses regarding landscape-level impacts were derived from theories about island biogeography and metapopulations. Thus, species presence and productivity sometimes are viewed as functions of patch characteristics such as size, shape, amount of edge, degree of isolation from larger, similar habitats, time since isolation, and dispersal, immigration, and extinction rates. Recommendations for mitigating fragmentation effects often include maintenance of reserves, increasing patch size, reducing edges, and enhancing connectivity through the use of corridors. While many of these theories are intuitively sound, there are few data to demonstrate their effectiveness in landscapes dominated by managed forests, including BLH forests. We suggest that high priority be given to using adaptive management to simultaneously test hypotheses about how biotic communities function in managed, BLH landscapes. Such information would help managers understand the consequences of their activities, provide them with more flexibility, and improve their ability to protect biological diversity while also meeting society's needs for forest resources.     

Traditional agroforestry systems of multi-crop “milpa” and “chichipera” cactus forest in the arid Tehuacán Valley,Mexico: their management and role in people’s subsistence

Agroforestry systems (AFS) derived from the cactus forest “chichipera” and cultivated with “milpa”, the traditional multi-crop system of maize-beans-squash were studied in the Tehuacán Valley, Mexico. Plant management types practiced by people, role of agricultural and forest resources in households’ subsistence, and consequences of changes in AFS were investigated through ethnobotanical, ecological, and economic approaches. People maintain in this AFS 122 plant species that provide useful products for 14 different purposes. Nearly 90% of useful plants are native to the region, representing 54% of all plant species recorded in the chichipera forest. Management strategies were identified occurring on 63 species at landscape, parcel, and individual plant levels. About 67% of managed plant species are left standing during clearance of vegetation; 35% are transplanted to the parcels’ surrounding area, 32% receive particular protection, and 10 species from other areas are cultivated inside the fields. During years of higher rainfall (~745 mm) AFS supply nearly 75% of the maize grain and 50% of the maize straw used as fodder by households. AFS with intermediate vegetation cover have higher economic value than monocultures and forest. However, plots with low forest cover and monocultures are progressively more common as consequence of socio-cultural processes. Local traditional ecological knowledge and management techniques are crucial for managing resilience of these AFS.     

Abundance and diversity of soil invertebrates in annual crops, agroforestry and forest ecosystems in the Nilgiri biosphere reserve of Western Ghats, India

Biologically mediated soil processes rely on soil biota to provide vital ecosystem services in natural and managed ecosystems. However, land use changes continue to impact on assemblages of soil biota and the ecosystem services they provide. The objective of the present study was to assess the effect of land use intensification on the distribution and abundance of soil invertebrate communities in the Nilgiri, a human-dominated biosphere reserve of international importance. Soil invertebrates were sampled in 15 land use practices ranging from simple and intensively managed annual crop fields and monoculture tree plantations through less intensively managed agroforestry and pristine forest ecosystems. The lowest taxonomic richness was found in annual crops and coconut monoculture plantations, while the highest was in moist-deciduous and semi-evergreen forests. With 21 ant species, agroforestry systems had the highest diversity of ants followed by forest ecosystems (12 species). Earthworms and millipedes were significantly more abundant in agroforestry systems, plantations and forest ecosystems than in annual crop fields. Ants, termites, beetles, centipedes, crickets and spiders were more abundant in forest ecosystems than in other ecosystems. It is concluded that annual cropping systems have lower diversity and abundance of soil invertebrates than agroforestry and natural forest ecosystems. These results and the literature from other regions highlight the potential role that agroforestry practices can play in biodiversity conservation in an era of ever-increasing land use intensification and habitat loss.     

Cost-effective strategies to conserve boreal forest biodiversity and long-term landscape-level maintenance of habitats

Setting aside parcels of land is the main conservation strategy to reduce the rate of biodiversity loss worldwide. Because funding for biological conservation is limited, it is important to distinguish the most efficient ways to use it. Here, we assess implications of alternative measures to conserve biodiversity in managed boreal forest landscapes. We calculated four alternative spatio-temporal scenarios and compared these to the current management regime over 100-year time period. In the alternative scenarios, a fixed amount of funding was invested in (1) permanent large reserves (each tens of ha in size), (2) permanent small reserves (each a few ha in size), (3) temporary small reserves (based on 10-year contracts with private land owners), and (4) green-tree retention (small groups of trees retained on clear-cuts). To assess biodiversity implications, we used habitat suitability indices to calculate overall habitat availability for five groups of red-listed and habitat-specific species associated with decaying spruce logs. The possibilities for timber harvests did not differ among the scenarios, but biodiversity performance was different. The scenarios with permanent reserves tended to outperform other scenarios, suggesting that conservation policies based on permanent reserves are the most cost-efficient in the long term. Results, however, varied among time scales and species groups. In the short term, a strategy of investment in temporary small reserves was the most efficient. Habitat for species associated with old spruce dead-wood and preferring shade was rare throughout all simulations, and therefore, it is likely that these species cannot be sustained in managed forests. Species that live on fresh dead-wood and are associated with forest edges coped well in all scenarios suggesting that such species will persist in managed landscapes without additional conservation efforts. Explicit definition of conservation objectives and time frames for conservation action are thus prerequisites for successful conservation planning.     

Revisiting the past: an essay on agroforestry definition

Concepts used by various authors are analyzed in order to define agroforestry and discuss, in detail, some ambiguous terms often encountered (biological and economic interactions, time sequences, etc.). Only those concepts which differentiate agroforestry from other non-agroforestry forms of land use are retained as part of the definition, which is: agroforestry is a form of multiple cropping under which three fundamental conditions are met: 1) there e exist at least two plant species that interact biologically; 2) at least one of the plant species is a woody perennial; and 3) at least one of the plant species is managed for forage, annual or perennial crop production.     

Agroforestry systems and biodiversity conservation in arid zones: the case of the Tehuacán Valley,Central México

The role of agroforestry systems in biodiversity conservation was investigated in the semiarid Tehuacán Valley, Central México. Richness and diversity of native plant species were compared between agroforestry systems (6 sampling sites) and the following forests (6 sampling sites) dominated by columnar cacti: (i) “chichipera” dominated by Polaskia chichipe; (ii) “jiotillal” dominated by Escontria chiotilla; and (iii) “garambullal” dominated by Myrtillocactus schenckii. Our information on genetic variation of dominant arboreal species in the study sites was reviewed and included in the analysis. Factors influencing household’s decisions to maintain vegetation cover were compiled through a survey and interviews and analyzed. All the samples of the agroforestry systems studied maintained on average nearly 59% plant species and 94% genetic variation of dominant cacti occurring in the forests, although their ability to preserve endemic rare species is limited. Social factors favoring maintenance of perennial species in agricultural plots include collective rules, households traditions, use of the plants maintained in the systems, and the environmental information gathered from NGOs, the local Biosphere Reserve, and researchers. However, agroforestry systems are losing their capability to maintain vegetation cover, mainly because of (i) decreasing amount of land managed by households, determined by a progressive fragmentation of the land area given to new families, (ii) adoption of technologies to intensify agriculture, and (iii) governmental programs penalizing the presence of vegetation patches within agricultural lands since they are considered “useless” areas. Necessary policies to stop degradation of the agroforestry systems and to improve their conservation capacity are discussed.     

Bird community responses to a gradient of site preparation intensities in pine plantations in the Coastal Plain of North Carolina

Although intensively managed pine forests are common in the southeastern US, few studies describe how combinations of mechanical (MSP) and chemical site preparation (CSP) and herbaceous weed control (HWC) techniques affect bird communities that use early successional habitats within young pine forests. Therefore, we examined effects of six treatments of increasing management intensity via combinations of MSP (strip-shear and wide spacing or roller chop and narrow spacing) and CSP (application or no application) treatments with banded or broadcast HWC on bird communities in six loblolly pine (Pinus taeda) plantations in the Coastal Plain of North Carolina, USA, for 8 years following site preparation. Wide pine spacing and strip-shear MSP increased bird abundance and species richness over narrow spacing and chopped MSP for 6 years after planting. Chemical SP reduced bird abundance in year 2, increased bird abundance in year 6, had no effect on abundance after year 7, and did not affect species richness in any year. Total bird abundance and species richness were similar between banded and broadcast HWC. Site preparation and HWC had no effect on bird diversity and bird communities were most similar in treatments of similar intensity. Site preparation and HWC had few or no effects on birds based upon migratory status, habitat association, or conservation value. The addition of chemical site preparation or HWC had little effect on birds beyond pine spacing, and bird abundance was not proportional to management intensity. Although we observed treatment effects, all treatments provided habitat used by a variety of bird species, and pine plantations may play an increasingly important role in bird conservation as forests become fragmented and converted to other land uses and as natural processes that create early successional habitat, such as fire, are suppressed.     

Characteristics of life-form and growth-form of plant species in an alpine ecosystem of North-West Himalaya

The present study was conducted in the alpine pastures of Tungnath (30° 14’ N and 79° 13’ E) to observe life-form and growth-form patterns of alpine plant species under grazed and ungrazed conditions and to work out the plant life form spectrum. Species were categorized as plant habit, height and length of growth-cycle and life-form classes according to Raunkiaer’s system. The results show that in total of 68 species at grazed site, hemicryptophytes (He) accounted for 50.00% species, followed by cryptophytes (26.47%), chamaephytes (16.18%), phanerophytes (4.41%) and therophytes (2.94%). At the ungrazed site in 65 plant species, hemicryptophytes (He) accounted for 49.23% species, cryptophytes (26.15%), chamaephytes (15.38%), phanerophytes (6.15%) and therophytes (3.08 % species). In general, hemicrptophyte are dominant in both sites i.e. graged and ungrazed. Growth form categories were classified as forbs, shrubs, grasses and sedges and undershrubs, according to plant habit and height. On the basis of length of the growth cycle, species were categorized as plant species of short growth cycle, intermediate growth cycle and long growth cycle. The short forbs of plant habit and height, had the highest emergence, and grasses and sedges had the lowest emergence in representative species. Percentage of species with long growth cycle was highest in both sites.     

Development and Status of Forestry Nature Reserves in China

The primary conservation objective in China is to establish nature reserves to protect biological resources and natural heritage, protect ecosystems which are of global importance or have unique regional features, protect endangered and threatened species and their habitat, and safeguard the genetic resources. By 2000, the number of nature reserves increased to 1,276, while at the same time, the total area protected in nature reserves was up to 123 million ha. Of the total number of reserves, 908 sites with a total area of some 102 million ha (68.39% of the total reserve area) were under control of the forestry system accounting for some 82.93% of all nature reserves in the country and 10.65% of China's territory. Management planning and administrative systems have been developed for all national nature reserves, but insufficient funding, a shortage of professional managers and inadequate reserve staffs have resulted in low levels of management effectiveness in many reserves. Many nature reserves starie     

Selection of diurnal roosts by red bats (Lasiurus borealis) in an intensively managed pine forest in Mississippi

Forest managers are increasingly expected to incorporate biodiversity objectives within forest landscapes devoted to timber production. However, data on which to base management recommendations for bats within these systems are limited. Although the red bat (Lasiurus borealis) is a widespread and common species in temperate forests of North America, little is known of its ecology within intensively managed pine (Pinus spp.) forests of the southeastern United States. Diurnal roost sites of red bats may be limiting on industrial pine forests due to a lack of large hardwoods within managed stands. Therefore, we investigated selection of day roosts by red bats at multiple spatial scales during June–September 2000 and May–August 2001 in an intensively managed pine landscape in east-central Mississippi, USA. We captured bats using 4-tier mist nets placed over water and attached 0.47–0.54 g radiotransmitters to captured red bats (n = 46). We located day roosts of red bats (n = 141 roosts of 27 bats) for the life of the transmitters. Red bats roosted in 16 species of hardwood trees (70% of day roosts) and loblolly pine (Pinus taeda; 30% of day roosts). In contrast to other studies in the southeastern United States, red bats roosted in pine trees and in midstory hardwood trees. Within thinned pine stands, red bats tended to prefer roost trees with a denser subcanopy and higher basal area as compared to random sites. Stand-level characteristics appeared more important than individual tree characteristics in choice of diurnal roosts. Except for adult males, logistic regression models of roost sites of red bats had high (≥79%) correct classification rates. Day roost site requirements of red bats may exhibit greater plasticity than previously thought. On our study area, intensive forest management appears compatible with diurnal roost needs of this species.