Vegetation Species Diversity Research Articles

Disproportionate effects of non‐colonial small herbivores on structure and diversity of grassland dominated by large herbivores

The response of semiarid grasslands to small, non‐colonial herbivores has received little attention, focusing primarily on the effects of granivore assemblages on annual plant communities. We studied the long‐term effects of both small and large herbivores on vegetation structure and species diversity of shortgrass steppe, a perennial semiarid grassland considered marginal habitat for small mammalian herbivores. We hypothesized that 1) large generalist herbivores would affect more abundant species and proportions of litter‐bare ground‐vegetation cover through non‐selective herbivory, 2) small herbivores would affect less common species through selective but limited consumption, and 3) herbivore effects on plant richness would increase with increasing aboveground net primary production (ANPP). Plant community composition was assessed over a 14‐year period in pastures grazed at moderate intensities by cattle and in exclosures for large (cattle) and large‐plus‐small herbivores (additional exclusion of rabbits and rodents). Exclusion of large herbivores affected litter and bare ground and basal cover of abundant, common and uncommon species. Additional exclusion of small herbivores did not affect uncommon components of the plant community, but had indirect effects on abundant species, decreased the cover of the dominant grass Bouteloua gracilis and total vegetation, and increased litter and species diversity. There was no relationship between ANPP and the intensity of effects of either herbivore body size on richness. Exclusion of herbivores of both body sizes had complementary and additive effects which promoted changes in vegetation composition and physiognomy that were linked to increased abundance of tall and decreased abundance of short species. Our findings show that small mammalian herbivores had disproportionately large effects on plant communities relative to their small consumption of biomass. Even in small‐seeded perennial grasslands with a long history of intensive grazing by large herbivores, non‐colonial small mammalian herbivores should be recognized as an important driver of grassland structure and diversity.

Vegetation and community changes of elm (Ulmus pumila) woodlands in Northeastern China in 1983–2011

Elm (Ulmus pumila), widely distributed in the north temperate zone, contributes to a special savanna-like woodland in typical grassland region in the northeastern China. This woodland performs a variety of ecological functions and environmental significance, such as decreasing soil erosion, stabilizing sand dunes, preserving species diversity. However, in the last approximate 30 years, the species composition, productivity and distribution area of elm woodland has decreased severely. A series of studies have been carried out to find out whether the climate changes or human disturbances caused the degradation of elm woodland and how these factors affected elm woodland. In this study, undisturbed, plowing and grazing elm woodland were investigated in 1983 and 2011 by using Point-Centered Quarter method. The relationship between vegetation changes and environmental factors was analyzed by Bray-Curtis ordination. The results show that in 2011, species diversity and understory productivity of undisturbed elm woodland decrease slightly compared to those of undisturbed elm woodland in 1983. However, nearly 60% of the species is lost in the plowing and grazing elm woodland relative to the species undisturbed elm woodland in 1983. Interestingly, plowing stimulates the growth of elm and certain understory species through furrowing soil and accelerating soil nutrient turnover rate. Grazing disturbance not only leads to species loss and productivity decrease, but also induces changes in elm growth (small, short and twisted). The mean age of the elm was 29 ± 2 yr in undisturbed and plowing elm woodland, while only 15 yr in the grazing elm woodland. The results of Bray-Curtis ordination analysis show that all sample stands clustered to three groups: Group I including the undisturbed sample stands of 83UE (undisturbed elm woodland in 1983) and 11UE (undisturbed elm woodland in 2011); Group II including sample stands of PE (elm woodland disturbed by plowing); Group III including samples stands of GE (elm woodland disturbed by grazing). The results indicate that the long time disturbance of the plowing and grazing have converted elm woodland to different community types. Climate change is not the primary reason causing the degradation of elm woodland, but plowing and grazing disturbance. Both plowing and grazing decrease the vegetation composition and species diversity. Grazing further decreases vegetation productivity and inhibits the growth of elm tree. Therefore, we suggest that reasonable plowing and exclusive grazing would be favorable for future regeneration of degraded elm woodland.

Vegetation Patterns and Species Diversity Along Elevational and Disturbance Gradients in the Baihua Mountain Reserve, Beijing, China

Vegetation and species diversity patterns in conservation areas near big cities are poorly known. These are important recreational areas used also for educational purposes. Therefore, investigations of local diversity patterns are urgently needed. The Baihua Mountain Reserve is close to the city of Beijing and is the northern end of the Taihang mountain range in north China. Sixty-one 10 × 20 m quadrats of plant communities were established along gradients for elevation (750–2043 masl) and disturbance (mainly due to tourism and agriculture). Data on species composition and environmental variables were measured and recorded in each quadrat. Two-way indicator species analysis and canonical correspondence analysis (CCA) were used to analyze the relationships between vegetation and environmental variables, while species diversity indices were used to analyze the pattern of species diversity. Twelve plant communities were found, mostly secondary forests with some plantations. These communities are representative of the vegetation in the mountains west of Beijing. Each community had a different composition, structure, and environment. The variation of plant communities was significantly related to elevation and disturbance and related to litter thickness, slope, and aspect. The cumulative percentage variance of species–environment relationships for the first 4 CCA axes was 89.6%. Elevation and disturbance intensity were revealed as the factors that most influenced community distribution and species diversity. Species richness, heterogeneity, and evenness all showed a “humped” pattern along elevational and disturbance gradients—the highest species diversity appeared in the middle elevation and under medium disturbance intensity. Recommendations regarding management measures are made.

Assessment of plants grown and maintained in home gardens in Odeda area Southwestern Nigeria

A survey of thirty (30) home gardens in Odeda Local Government Area (LGA) of Ogun State, Southwestern Nigeria was conducted to assess plants grown and maintained by household members and the diversity of vegetal species and their uses. Semi-structured questionnaire and structured interviews were used to collect useful information. A total of 120 plant species belonging to 50 botanical families were documented. From the data, Euphorbiaceae, Solanaceae, Rutaceae, Malvaceae, Caesalpiniaceae, Poaceae and Apocynaceae (in order of decreasing number of species) were the most frequent families. Taxa such as Musa species,Vernonia amygdalina, Citrus species, Psidium guajava and Terminalia catapa were found to be the common food/medicinal plants as evidenced by their densities in the study sites. The household members cited most of the plants as food; others as medicinal and ornamentals. Miscellaneous uses include cosmetics, ceremonial and scouring. Species composition, shapes/structures as well as plant uses are discussed. Home garden products serve alimentary purposes and represent promising base materials for poverty alleviation and may also help to augment “fresh” food nutrient intake. The wealth of the home gardens may be related to the rural origin and to the culture of the owners who still keep a cultivation tradition. Some plant species are frequent. This may suggest uniformity in plant use and could contribute to the conservation of local species. Home gardens can also be regarded as ‘humble’ germplasm bases; hence, the need to re-energize the productive capacity of home gardens. Key words: Agro-forest systems, home garden, ethnobotany, diversity, Odeda, Southwestern Nigeria.

Vegetation, soils and seed banks of limestone grasslands are still impacted by former cultivation one century after abandonment

This study identifies the long lasting impacts of former cultivation on soils, seed banks and above-ground vegetation of limestone grasslands. We compared the resilience of three crop fields cultivated in the 19th century and abandoned (Abandoned Fields) with three grasslands which have never been cultivated (Old Grasslands). Grasslands were located in the Nature reserve of Grand-Pierre and Vitain valleys in France. Sites were identified using historical sources. Chemical and physical soil properties, above-ground vegetation and soil seed bank (0–10 cm and 10–20 cm) were studied. Data were analysed using a multivariate and univariate analyses to detect the effects/impacts of ancient cultivation. Our results clearly show that soil properties (e.g., calcium, carbonate, clay contents), above-ground vegetation (species diversity, moss and lichen cover) and seed bank (floristic composition, species-richness and diversity) are still impacted more than one century after their abandonment. Species richness of both above ground vegetation and seed bank are higher in old grasslands than in formerly cultivated fields. In the seed bank of the formerly cultivated soils we also found the presence of a very rare arable weed species (Althaea hirsuta) which has not been inventoried for a long time in the above-ground vegetation of the nature reserve. The resilience of formerly cultivated limestone grasslands might be influenced by the present management regime (site effect). Nevertheless, the resilience period of limestone grasslands is very long-more than one century-and return to an initial state might be difficult or impossible to reach.

Supporting analysis of floodplain restoration options by historical analysis

Abstract The presented case study deals with the hydromorphological alterations over a period of nearly 400 years and their ecological effects as shown by macrophytes in the urban floodplain Lobau along the Danube River within the city limits of Vienna for a period of about 160 years. Socio-economic pressures, such as flood protection (especially the Vienna Danube Regulation between 1869 and 1875), navigation and hydropower production, have modified the natural channel network in this anabranching river section into a shallow lake system in which habitat aging and sediment accumulation proceed. The aquatic and semi-aquatic habitats and their rich biodiversity would become reduced severely without any restoration measures promoting enhanced surface water exchange. The effects of restoration measures approaching pre-regulation conditions were evaluated for the macrophyte vegetation, a key ecosystem component. To collect monitoring data of the pre-regulation conditions, detailed literature data and mappings since 1846 up to recent surveys including the long-term development of aquatic vegetation patterns and aquatic habitat composition in the floodplain Lobau were analyzed. The potential effects were evaluated by analyzing how hydraulic parameters (water velocity and suitable habitat area for macrophytes) have controlled macrophyte composition and development. The study aimed at assessing the differences between the current and the historic situation caused by human impacts at different spatial scales and changes over time. By evaluating these differences we discussed intended as well as unintended effects of potential restoration measures. Primarily due to the loss of aquatic habitats the species diversity of aquatic vegetation is currently endangered and would decline without any restoration measures. However, a complete upstream reconnection of the remaining floodplain area Lobau to the Danube main channel (maximum achievable restoration goal) could also have unintended negative effects such as facilitation of the dispersal of non-native invasive species, decline of palaeopotamal species, and exposure of the floodplain to the present, altered water regime. Considering these alterations, the design of restoration projects would need to be adapted accordingly. In the presented case study Lobau, a partial reconnection instead of a complete reconnection might be the option optimizing the given management goals best.

Direct and indirect bottom-up and top-down forces shape the abundance of the orb-web spider Argiope bruennichi

Species abundance in local communities is determined by bottom-up and top-down processes, which can act directly and indirectly on the focal species. Studies examining these effects simultaneously are rare. Here we explore the direct top-down and direct and indirect bottom-up forces regulating the abundance and predation success of an intermediate predator, the web-building spider Argiope bruennichi (Araneae: Araneidae). We manipulated plant diversity (2, 6, 12 or 20 sown species) in 9 wildflower strips in a region of intensive farmland. To identify the major factors regulating the distribution and abundance of A. bruennichi, we quantified three characteristics of vegetation (species diversity, composition and vegetation structure) as well as the spider's prey community and natural enemies. The distribution and abundance of A. bruennichi was regulated by combined bottom-up and top-down processes as well as by direct and indirect interactions between trophic levels. Four main factors were identified: (1) the strong direct effect of vegetation structure, (2) the positive effect of plant species diversity, which affected spider abundance directly and indirectly through increased densities and size of flower-visiting prey species, (3) the positive or negative direct effects of different plant species, and (4) the strongly negative direct effect of predacious hornets. The advantage of taking a global approach to understand the regulation of species abundance is highlighted first by the quantification of the relative importance of factors, with a surprisingly strong effect of hornet predators, and second by the discovery of a direct effect of plant diversity, which raises intriguing questions about habitat selection by this spider.

Remotely sensed indicators of forest conservation status: Case study from a Natura 2000 site in southern Portugal

The successful implementation of habitat conservation measures demands regular and spatially explicit monitoring and reporting on conservation status at a range of scales, based on indicators of both habitat range and condition (structure and functions required for long-term maintenance). Such is the case with the Natura 2000 protected areas in Europe. Focusing on the cork oak (Quercus suber) forests of one such area, the Serra de Monchique in southern Portugal, we test the complementarity and joint effectiveness of airborne multispectral and laser scanning (lidar) in providing robust indicators of conservation status. Principal forest types and other land covers are mapped to an accuracy of up to 70% (11 land cover classes) and 81% (5 classes) by fusing the two remote sensing datasets, results that are superior to using either one alone. Using previously tested relationships between lidar height metrics, forest vegetation structure and species diversity, we develop a map predicting areas of high (22% of area), medium (25%) and low (53%) condition. We recommend the further development and testing of remotely sensed range and condition indicators of conservation status for their application in important forested sites across Europe and beyond.

Effects of type and size of gaps created by simulation of cattle activities on the recovery and similarity of vegetation community

AbstractCattle activities may affect pasture biodiversity and productivity. This study investigated the effects of type and size of gaps simulating cattle activities on the recovery and similarity of vegetation community in pastures. Two types of gaps (bare ground and mown vegetation as simulated trampling and grazing by animals, respectively) differing in size (20–100 cm in diameter) were artificially created in three vegetation communities (sown, aged sown and native pastures), and vegetation recovery in the gaps was monitored. Undisturbed patches (100 × 100 cm) were also monitored as a control. The similarity of botanical composition to the control was lowest in the 20 cm gaps, irrespective of the disturbance or vegetation types. Vegetation in the bare ground gaps tended to recover slower in 20 cm gaps than in 100 cm gaps in all vegetation types. Small gaps created by cattle activities may enhance vegetation species diversity while it may decrease productivity of pastures.

Post‐fire recovery of revegetated woodland communities in south‐eastern Australia

AbstractThe primary goal of restoration is to create self‐sustaining ecological communities that are resilient to periodic disturbance. Currently, little is known about how restored communities respond to disturbance events such as fire and how this response compares to remnant vegetation. Following the 2003 fires in south‐eastern Australia we examined the post‐fire response of revegetation plantings and compared this to remnant vegetation. Ten burnt and 10 unburnt (control) sites were assessed for each of three types of vegetation (direct seeding revegetation, revegetation using nursery seedlings (tubestock) and remnant woodland). Sixty sampling sites were surveyed 6 months after fire to quantify the initial survival of mid‐ and overstorey plant species in each type of vegetation. Three and 5 years after fire all sites were resurveyed to assess vegetation structure, species diversity and vigour, as well as indicators of soil function. Overall, revegetation showed high (>60%) post‐fire survival, but this varied among species depending on regeneration strategy (obligate seeder or resprouter). The native ground cover, mid‐ and overstorey in both types of plantings showed rapid recovery of vegetation structure and cover within 3 years of fire. This recovery was similar to the burnt remnant woodlands. Non‐native (exotic) ground cover initially increased after fire, but was no different in burnt and unburnt sites 5 years after fire. Fire had no effect on species richness, but burnt direct seeding sites had reduced species diversity (Simpson's Diversity Index) while diversity was higher in burnt remnant woodlands. Indices of soil function in all types of vegetation had recovered to levels found in unburnt sites 5 years after fire. These results indicate that even young revegetation (stands <10 years old) showed substantial recovery from disturbance by fire. This suggests that revegetation can provide an important basis for restoring woodland communities in the fire‐prone Australian environment.

Indirect drivers of plant diversity-productivity relationship in semiarid sandy grasslands

Abstract. Although patterns between plant diversity and ecosystem productivity have been much studied, a consistent relationship has not yet emerged. Differing patterns between plant diversity and productivity have been observed in response to spatial variability of environmental factors and vegetation composition. In this study, we measured vegetation cover, plant diversity, productivity, soil properties and site characteristics along an environmental gradient (mobile dune, semi-fixed dune, fixed dune, dry meadow, wet meadow and flood plain grasslands) of natural sandy grasslands in semiarid areas of northern China. We used multivariate analysis to examine the relationships between environmental factors, vegetation composition, plant diversity and productivity. We found a positive correlation between plant diversity and productivity. Vegetation composition aggregated by the ordination technique of non-metric multidimensional scaling had also a significantly positive correlation with plant diversity and productivity. Environmental gradients in relation to soil and topography affected the distribution patterns of vegetation composition, species diversity and productivity. However, environmental gradients were a better determinant of vegetation composition and productivity than of plant diversity. Structural equation modeling suggested that environmental factors determine vegetation composition, which in turn independently drives both plant diversity and productivity. Thus, the positive correlation between plant diversity and productivity is indirectly driven by vegetation composition, which is determined by environmental gradients in soil and topography.

Distribution patterns of groundwater‐dependent vegetation species diversity and their relationship to groundwater attributes in northwestern China

ABSTRACTThe study of the patterns of plant species diversity and the factors influencing these patterns is the basis of ecology and is also fundamental to conservation biology. Groundwater‐dependent vegetation (GDV) must have access to groundwater to maintain their growth and function, and this is especially common in arid and semi‐arid regions, including north‐western China. In this paper, plant species diversity and groundwater attributes (composition and depth) were investigated in 31 plots in the Ejina Delta in north‐western China to determine whether groundwater attributes influenced patterns species diversity in GDV. Detrended canonical correspondence analyses and generalised additive models were performed to analyse the data. A total of 29 plant species were recorded in the 31 plots; perennial herbs with deep roots had an advantage over all other groups, and GDV species diversity was primarily affected by groundwater depth (GWD), salinity (SAL) and total dissolved solids (TDS), HCO3−, Ca2+, pH, and SO42−. The herb layer species diversity and total species diversity reached their maximum in similar, moderate environmental conditions. The diversity of the tree species was influenced by SAL and TDS and was maximal at large values of GWD and low values of SAL and TDS. The diversity of shrub species was affected by Ca2+ and Mg2+ and was maximal low GWD and high SAL and TDS. Patrick's and Shannon–Wiener's index of the total community diversity presented a bimodal pattern along gradients of GWD and SAL, whilst Simpson's and Pielou's index showed a partially unimodal pattern. On the basis of field investigation and the analysis of field data, we concluded that the perfect combination of GWD and SAL for GDV species diversity is 2 m and 1·8 g l−1, respectively. The appropriate combination range is 2–5 m and 1·8–4·2 g l−1, and the critical combination for the damaged GDV species diversity is 5 m and 4·2 g l−1. Copyright © 2012 John Wiley & Sons, Ltd.

El impacto de la migración en el manejo de solares campesinos, caso de estudio La Purísima Concepción Mayorazgo, San Felipe del Progreso, Estado de México

La diversificación ocupacional se ha convertido en un elemento importante de los modos de vida rurales, especialmente en los países en desarrollo. Entre las estrategias de diversificación que han sido frecuentemente objeto de estudio, destaca la migración debido al importante y creciente número de campesinos que recurren a ella con el fin de mejorar sus condiciones de vida. Sin embargo, poco se ha documentado sobre las repercusiones que tienen estos despla­zamientos de población en el desarrollo de las actividades agrícolas y el manejo de recursos naturales en las comunidades de origen. Por ello, este documento tiene como objetivo determinar cuál es el impacto que ha tenido la migración en el manejo de solares campesinos en una comunidad de origen mazahua; particularmente se hace un estudio comparativo entre la riqueza y diversidad de especies vegetales, las prácticas agrícolas y las diferentes funciones que tienen estos espacios para las familias de migrantes y no migrantes.

Scale dependent effects of environmental factors on vegetation pattern and composition in Horqin Sandy Land, Northern China

Understanding the relationship between vegetation–environment is very important to manage arid and semiarid ecosystems. However, information on how environment factors influence the vegetation patterns at different spatial scales in semiarid area ecosystem is lacking. We measured vegetation compositions and environment characteristics form 55 sample sites in grassland habitat (flood plain grassland, wet meadow, dry meadow) and sand dune habitat (fixed dune, semi-fixed dune, mobile dune) in Horqin Sandy Land. Multivariate analyses were used to examine the relationship between vegetation patterns and environment factors at the two scales of habitat and region. Vegetation cover, aboveground biomass, soil organic carbon (C), total nitrogen (N) and soil water content decreased from grassland habitat to sand dune habitat. Vegetation cover increased with the increase in soil water content in grassland habitat. Vegetation cover, species diversity and aboveground biomass increased with the increase in soil organic C, total N and EC in sand dune habitat. The most important complex gradient determining vegetation pattern and composition showed a region scale relationship with the combination of soil properties and topography features. Soil water content, EC and altitude were closely related to the vegetation distribution in grassland habitat, whereas soil organic C, total N and EC were significantly related to the vegetation distribution in sand dune habitat. Our results suggest that vegetation–environment relationships are dependent on the scale of observation. Thus, the interpretation of the vegetation pattern and composition in semiarid area needs to consider the spatial scales and habitats at which important environmental variables actually vary.

Long-term application of biomass and reduced use of chemicals alleviate soil compaction and improve soil quality

The heavy traffic of agricultural equipment in citric orchards as a result of frequent application of pesticides and fungicides have led to soil compaction and a biological imbalance in these agricultural ecosystems, decreasing crop yields and increasing production costs. The purpose of this work was to assess the effects of spontaneous vegetation (weed) management in interrows following the replacement of agrochemicals with alternative inputs known to have a low impact on the environment. This experiment was conducted in a commercial orchard of ‘Murcott’ tangor (Citrus reticulata, Blanco×Citrus sinensis, Osbeck). Highly soluble sources of NPK were substituted with a mixture of 65% rice bran+35% castor bean meal (3.0%N), thermophosphate (17.5% P2O5) and potassium sulfate (48%K2O). Synthetic pesticides were replaced with alternative pest controls, such as Bordeaux mixture and lime sulfur. Mechanical mowing was used instead of herbicides, and the mowed weeds were spread under the citrus plants canopy for mulch. This treatment, referred to as alternative management (AM), was performed for three years and compared with a control area, referred to as conventional management (CM), in which conventional cultivation practices and pesticide applications were maintained. The soil compaction, the fruit yield and select biological parameters were used for our assessment. When compared to the CM treatment, AM provided a higher vegetation cover and species diversity (especially for grasses), reduced soil resistance to penetration, better root growth in the topsoil layer, increased root colonization by arbuscular mycorrhizal fungi (AMF), increased viable spores in the soil and a higher leaf boron (B) concentration. Furthermore, the infestation of the AM plots with the mealybug, Orthezia praelonga, was significantly lower, and the fruit yield was higher in the third year. These results indicate that agricultural management practices focused on a reduced impact on the agroecosystem, mainly with regard to biological processes, are promising techniques for sustainable agriculture.

Analysis on Slope Revegetation Diversity in Different Habitats

Quarrying for constructions has left many bare rocky slopes, in order to recreate biodiversity, artificial revegetation methods have been widely used in the ecological restorations. The study selected several rocky slopes in Zhoushan City for vegetation survey, recorded vegetation species and habitat factors in different sample plots. Based on vegetation data, community parameters such as vegetation diversity indices were computed for statistical analysis, then the relationship between the habitat factors and the slope re-vegetation were revealed. The results showed, the changes of vegetation community diversity in different habitats were obvious, furthermore, for the four habitat factors, significant correlations between slope aspect and vegetation diversity, also slope position and vegetation diversity had been found. Thus, revegetation of rocky slope must be based on characteristics of different local habitats, which can make significant contribution to maintain species diversity and community stability of vegetation.

Can’t see the grass for the trees? Community values and perceptions of tree and shrub encroachment in south-eastern Australia

Land-use change has resulted in tree and shrub encroachment in many agricultural regions world-wide, resulting in ‘derived’ ecosystems which differ from ‘natural’ elements in terms of structure and composition. Management of derived vegetation can be contentious, because policy makers, stakeholders and community members often hold conflicting value orientations. Developing socially acceptable and effective native vegetation management strategies requires a clearer understanding of the ways people value and perceive derived vegetation communities. Research was conducted in central NSW, Australia, to explore individual values and perceptions of changes to derived vegetation communities, through a group interview with government conservation-based staff, and semi-structured interviews with local community townspeople and farmers. Photographs showing three derived vegetation communities and two hypothetical changes to open woodland communities were used to set a context for discussion. Findings showed that participant values and perceptions encompassed four broad themes relating to diversity of vegetation species, degree of vegetation naturalness, extent and location of derived vegetation and contrasting management concerns and constraints. The findings suggest that acceptable and effective native vegetation policy will require interventions and incentives which are tailored to the local context, and acknowledge landholder management concerns and external constraints associated with woody encroachment in farming country.

Impact of tropical forest degradation on nymphalid butterflies: A case study in Chandubi tropical forest, Assam, India

Study examines the hypothesis, whether the diversity of Nymphalid butterflies in tropical primary forest of Chandubi is associated with vegetation structure and canopy openness and that this relationship differs between butterfly taxa in relation to phylogenetic differences in light and shade preferences. Study has emphasized whether the increasing diversity of butterflies in degraded tropical forest is associated with the loss of species with restricted geographical distribution. Study considered altogether eight habitat variables and the t-test using equal variance, Spearman rank correlation and multiple regressions were also used for statistical analyses. Species diversity was analyzed using Margalef’s D indices that indicate both the species richness and abundance. Bootstrap method was used to compare the diversity among samples. PCA was done to examine the relationship between vegetation structure and species diversity in primary and degraded forest. The relationship between vegetation factor scores and species diversity in each sampling station in primary and degraded forest was analyzed using stepwise multiple regression. Results indicates that the butterflies species sampled in closed canopy forest had more restricted geographical distribution than those being sampled in disturbed forest. The species with greater light preference had significantly wider geographical distribution, whereas the species with greater shade preferences had significantly narrower geographical range. The stepwise analysis of multiple regressions between the diversity indices of shade groups of butterflies and vegetation density (PRIN 1) of closed forest shows a significant positive relationship, but the relationship was negative when similar analysis was carried out between species diversity indices of light preferred groups and vegetation density. Majority of closed canopy forest butterflies are sensitive to changes in moisture availability and humidity. Thus, changes in canopy cover and light penetration through microclimatic effects on adult and larval survival does have an impact on butterfly distributions and abundance. While the species richness and diversity are higher in degraded forest, the conservation value of primary forest lies more in the presence of species with restricted ranges. Owing to loss of diverse vegetation in degraded forest, the dense canopy cover and transparent ground cover has been reduced and thus leading to decline of forest butterflies species. Study has clearly indicated the strong and significant relationship that exists between the species of narrow range of geographical distribution and species shade preference. The restricted ranges species are affected due to forest degradation. Thus, clearly bringing into light, that increasing diversity in degraded forest is associated with the loss of species with restricted geographical distribution. Key words: Nymphalid butterflies, forest degradation, primary forests, conservation value, endemic species, geographic distribution range, light and shade groups, phylogeny, tropical forests.

Net primary productivity and species diversity of herbaceous vegetation in banj-oak (Quercus leucotrichophora A. Camus) forest in Kumaun Himalaya, India

Net primary productivity and species diversity of herbaceous vegetation of banj-oak (Quercus leucotrichophora A. Camus) forest in Kumaun Himalaya, India were analyzed. Across different growth forms (tall forbs, short forbs, cushion and spreading forbs, grasses), short forbs were most dominant component during rainy season (IVI=152) and winter season (IVI=167) and grasses during the winter season (IVI=148). Maximum above-ground production occurred during rainy season (132.5 g m−2) and minimum during winter season (2.8 g m−2). Below-ground production was maximum (85.9 g m−2) during winter season and minimum (14.9 g m−2) during summer season. Annual net shoot production was 150 g m−2 and below-ground production was 138 g m−2. Of the total input 61 % was channeled to aboveground parts and 39% to below-ground parts.

Recovery of Vegetation Structure and Species Diversity after Shifting Cultivation in Northwestern Vietnam, with Special Reference to Commercially Valuable Tree Species

A fallow stand (FS) in northwestern Vietnam that was created by shifting cultivation 32 years earlier had 43% of the species number, 72% of the stem density, and 53% of the basal area when compared with nearby old-growth forest (OGF); however, the values for commercial species were lower at 35%, 67%, and 26%, respectively. In terms of species diversity, the Shannon index of OGF (3.4) was significantly higher than that of FS (2.6), while the differences were not significant in terms of Evenness and species-size class distribution. Both FS and OGF had similar patterns of stem diameter frequency distribution but the diameters were more diverse in OGF compared to FS according to the Shannon index. Fallow stand was characterized by only 2 canopy layers (lower than 10 m and 10–20 m) and was simpler in vertical structure than that of OGF which included an additional upper canopy layer higher than 20 m. Our results indicate that increasing stem density of commercial species is necessary and can be realized by artificial seeding, planting seedlings, and/or natural regeneration from remaining mother trees in the fields.