Shrub Species Diversity Research Articles

Comparison of woody species diversity between managed and unmanaged forests considering vertical structure in Hyrcanian forests, Iran

Nouri Z, Zobeiri M, Feghhi J, Amiri GZ, Marvie Mohadjer MR. 2015. Comparison of woody species diversity betweenmanaged and unmanaged forests considering vertical structure in Hyrcanian forests, Iran. Biodiversitas 16: 95-101. Biodiversityconservation is increasingly considered a key to sustainable forest management and understanding biodiversity in forest ecosystems isessential to reveal forest dynamics, so this study aims to compare tree and shrub species diversity and vertical species distributionbetween two managed and unmanaged forest stands. The study area was consisted of two adjacent districts in which two differentmanagement practices were implemented. In 1000 m2 circular plots, type of species and diameter at breast height (D.B.H) of all treeslarger than 2.5 cm as well as type of species of all shrubs and vertical distribution of tree species were recorded. In addition to richness,evenness and heterogeneity indices were calculated for whole tree and shrub species and also for each tree layer. The results showed thattree species diversity indices were significantly greater in the unmanaged area, whereas richness and heterogeneity indices of shrubswere greater in the managed area. Comparing the biodiversity indices indicated that richness index had the greatest value in theunderstorey and heterogeneity indices were greatest in the middle storey in both regions. Greater amounts of evenness were detected inthe middle- and over storey of unmanaged and managed areas, respectively. As forestry operations result in change in various forestcharacteristics such as species diversity, it is essential to assess and monitor the effect of logging operations on forest diversityHyrcanian forests of Iran.

Diversity and geographic distribution pattern of shrub species in xinjiang, China

Using list of flora and geographical information, coupled with GIS and statistical methods, the study was to investigate spatial patterns of shrub species diversity in Xinjiang, China, and its relationship with geographical factors. Presently, there are 416 species (including 20 varieties) of shrubs belonging to 35 families and 109 genera in Xinjiang. Shrubs are confined to the northern part of Xinjiang at families, genera and species levels, and Altay prefecture, Yili prefecture and Urumqi are three centers of shrub diversity in Xinjiang. Species richness decreases across Xinjiang from east to west, and has a relationship with other geographical factors. From south to north, shrub species richness increases due to precipitation in Northern Xinjiang being significantly higher than in the south of the province. This results in an increase in shrub diversity with increasing latitude which needs further analysis combining with climate data. Through correlation analysis, species richness was negatively correlated with area. This is due to larger counties containing a large area of desert and Gobi in Xinjiang. The correlation between Xinjiang shrub plant species richness and altitude is significant. As a whole, latitude, altitude mean value and altitude variation significantly affect the distribution patterns of shrub species richness in Xinjiang, with latitude having the strongest influence.

Bayesian Estimation of Shrubs Diversity in Rangelands under Two Management Systems in Northern Syria

The diversity of shrubs in rangelands of northern Syria is affected by the grazing management systems restricted by the increase in human and livestock populations. To describe and estimate diversity and compare the rangeland grazing management treatments, two popular indices for diversity, the Shannon index and the Simpson index, were studied for the four combinations of two sites, Hammam and Obeisan, and two grazing methods, Closed and Open, using frequentist and Bayesian approaches. We simulated the a priori and a-posteriori distributions of the Shannon and Simpson diversity indices, where from a range of values for a constant in the a priori distribution the best value normalizing the distribution of the diversity indices was chosen. The Bayesian diversity estimates were higher than their frequentist counterparts and had lower standard errors. The grazing methods at each site and sites under each grazing method delivered significant diversity of shrub species. The Bayesian estimates resulted in lower p-values than the frequentist approach for two cases reflecting in Bayesian method’s higher power. Bayesian approach is recommended as it has a wider framework for inference on diversity studies.

More efficient aboveground nitrogen use in more diverse Central European forest canopies

We hypothesized that biodiversity improves ecosystem functioning and services such as nutrient cycling because of increased complementarity. We examined N canopy budgets of 27 Central European forests of varying dominant tree species, stand density, and tree and shrub species diversity (Shannon index) in three study regions by quantifying bulk and fine particulate dry deposition and dissolved below canopy N fluxes. Average regional canopy N retention ranged from 16% to 51%, because of differences in the N status of the ecosystems. Canopy N budgets of coniferous forests differed from deciduous forest which we attribute to differences in biogeochemical N cycling, tree functional traits and canopy surface area. The canopy budgets of N were related to the Shannon index which explained 14% of the variance of the canopy budgets of N, suggesting complementary aboveground N use of trees and diverse understorey vegetation. The relationship between plant diversity and canopy N retention varied among regional site conditions and forest types. Our results suggest that the traditional view of belowground complementarity of nutrient uptake by roots in diverse plant communities can be transferred to foliar uptake in forest canopies.

DIVERSIDAD DE ESPECIES ARBUSTIVAS EN UNA ZONA SEMIÁRIDA DEL CENTRO DE MÉXICO

La diversidad alfa (verdadera) y la diversidad beta (recambio y anidamiento) de especies arbustivas se evaluaron en la zona semiárida del estado de Hidalgo, México. El índice de valor de importancia de las especies se relacionó con variables edáficas y elementos climáticos. Se reportan 46 especies arbustivas pertenecientes a 21 familias, entre las que sobresalen Asteraceae y Fabaceae. El mayor número de especies efectivas registradas en un sitio fue de 7.8 y el menor de 1.6. La diversidad beta fue alta (0.9), lo cual se explica principalmente por el recambio de especies entre sitios (0.87) y en menor medida por el anidamiento (0.38). Las variables ambientales que mejor explicaron la distribución de las especies fueron la precipitación, el porcentaje de arena, el pH y el nitrógeno. Los resultados coinciden con lo documentado en otras zonas semiáridas, donde la alta diversidad regional se debe a un alto recambio de especies generado por la heterogeneidad ambiental que se muestra como un mosaico de condiciones, tanto de los elementos climáticos como de las características edáficas.

Unpaved road verges as hotspots of fleshy-fruited shrub recruitment and establishment

Hypothetical low-quality habitats can hold an overlooked conservation value. Some frugivorous mammals such as the red fox (Vulpes vulpes) and the European rabbit (Oryctolagus cuniculus) disperse many viable seeds of fleshy-fruited shrubs along the verges of soft linear developments (SLD), such as trails and firebreaks. However, seed arrival does not guarantee plant recruitment, since several post-dispersal processes can alter seed rain. To examine whether SLD verges assist shrub recruitment and establishment, we compared the density and the structure of a community of Mediterranean shrubs between SLD verges and the adjacent scrubland.Both seedlings and adult fleshy-fruited shrubs dispersed by foxes and rabbits reached higher densities along SLD verges than in the scrubland, suggesting SLD verges can be suitable habitats for shrub recruitment and establishment. Bird-dispersed shrubs showed a similar pattern, whereas shrubs dispersed by ungulates and badgers (Meles meles) as well as rockroses (Cistaceae) showed similar densities in both habitats. Shrub species composition and diversity were similar between habitats.Due to a marked differential seed arrival, SLD verges housed higher densities of fleshy-fruited shrubs than the adjacent scrubland. Established shrubs may attract seed-dispersing wildlife, and create proper environments for plant recruitment, generating a reforestation feedback. Incipient shrub populations along roadsides may act as stepping stones with potential to connect isolated populations in fragmented landscapes, where SLD are pervasive. We recommend careful management of frugivore populations and SLD verges in order to favor the diversity and the structural complexity of native vegetation while preventing the spread of invasive species.

Factors affecting woody plant species diversity of fragmented seasonally dry oak forests in the Mixteca Alta, Oaxaca, Mexico

We explored the relationship between fragment area, topographic heterogeneity, and disturbance intensity with tree and shrub species diversity in seasonally dry oak forest remnants in the Mixteca Alta, Oaxaca, Mexico. The fragments are distributed in a matrix of eroded lands and crop fields, have a complex topography, and are disturbed by plant extraction and trail opening. Sampling was conducted in 12 fragments from 12-3 211 ha. Topographic heterogeneity was estimated by the fragment's standard deviation in slope-aspect, slope, and altitude. The density of stumps and roads were used as estimators of disturbance intensity. Fisher's α diversity ranked from 0.95 to 4.55 for the tree layer; and 2.99 to 8.51, for the shrub layer. A structural equation model showed that the diversity of woody plants increases with topographic heterogeneity and disturbance in the remnants. When these 2 variables were considered, diversity tended to decrease with fragment size probably because smaller fragments have a greater perimeter-to-area ratio and therefore proportionally offer more opportunities for pioneer species colonization. Indeed, the tree-to shrub-layer diversity ratio increased with fragment size. Conservation strategies in fragmented forests must consider the fragment's environmental heterogeneity, the disturbance type and intensity, and the species to be preserved.

Shrubby today but not tomorrow? Structure, composition and regeneration dynamics of direct seeded revegetation

Summary The establishment of direct seeded revegetation is well researched. However, there is little understanding of whether revegetation simplifies with age and loses many of the short‐lived understorey shrub species that provide critical resources for birds and other fauna, or regenerates sufficiently to be self‐sustaining. We sought to address this by investigating the change in structure and composition of 33 direct seeded sites established by Greening Australia between 1990 and 1996 in the Southern Tablelands of NSW. Transects were used to collect data describing the abundance and richness of woody plants in 1998 and 2008, and the abundance of woody plant regeneration in 2008. Our analysis showed the predicted number of live stems per metre declined exponentially from 5.8 stems/m (∼17 000 stems/ha) at age 1.5 years to 1.5 stems/m (∼4500 stems/ha) at age 17.5 years. Predicted woody plant species richness also declined with age, with a linear relationship. The number of species in the seed mix affected predicted woody plant species richness. However, large increases in seed mix richness produced relatively small increases in predicted species richness. Regeneration (new stems) was present at high levels (>100 stems/ha); however, 82% of regeneration appeared to originate from delayed germination of sown seed rather than seed from established plants (recruitment). The predicted abundance of new stems (delayed germination and recruitment) declined with age, and for a given age increased with row width. Young stands (11.5 years), seeded with wide rows (4 m), had approximately six times the new stems of similar aged stands seeded with narrow rows (2 m). Our results indicate direct seeded stands simplify with age, becoming less dense and containing fewer species. Maintaining a diversity of shrub species in direct seeded sites may therefore require ongoing disturbances (scarifying, scalping, fire, thinning) of established sites and changes to establishment techniques for new sites. We suggest further research to establish the status of soil seed banks in direct seeded sites, testing different forms of disturbances to trigger regeneration in older revegetation sites and establishing new sites using wide rather than narrow rows and seed mixes enriched with species from genera other than Eucalyptus or Acacia.

An analysis of vegetation indices in relation to tree species diversity using by satellite data in the northern forests of Iran

Vegetation indices have been introduced for analyzing and assessing the status of quantitative and qualitative characteristics of vegetation using satellite images. However, choosing the best indices to be used in forest biodiversity and vegetation is one of the important problems faced by the users. The purpose of this research is to evaluate six vegetation indices in the analysis of tree species diversity in the northern forests of Iran. The present research uses LISS III sensor data from IRS-P6 satellite. Geometric rectification of images was performed using ground control points, and Chavez model was used for atmospheric correction of the data. The six spectral vegetation indices included NDVI, IPVI, Ashburn Vegetation Index (AVI), TVI, TTVI, and RVI. Shannon–Wiener species diversity index was used to analyze diversity, and the value of the index was calculated in each sample plot. Then, the spectral values of each sample plot were extracted from different bands. The best subset regression was used to analyze the relationship between species diversity and the related bands. The results obtained from the regression showed that polynomial equations under scrutiny as independent variables can assess tree and shrub species diversity better than other bands and compounds used (R 2 = 0.47). The obtained results also indicated a higher capacity in the case of the AVI index for estimating tree species diversity in the under study area.

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.

Structure, Composition and Diversity of Horticulture Trees and Agricultural Crops Productivity under Traditional Agri-Horticulture System in Mid Hill Situation of Garhwal Himalaya, India

Productivity of agricultural crops under traditional agri-hortculture system alongwith structure, composition and diversity of fruit trees and shrub species in mid hill situation of Garhwal Himalaya, India between 1000 to 2000 m asl during summer and winter seasons on northern and southern aspect were studied. The tree density, composition and diversity in the system varied depending upon aspect, landholding and requirements of the farmers. A total of 12 fruit tree species were recorded in agri-horticulture system; of which 4 trees were common in northern and southern aspect and 6 trees were only noticed in northern aspect while 2 in the southern. The apple tree (Malus domestica) was recorded to be dominant fruit tree species with highest IVI values on both northern and southern aspect with prime preference by the farmers for high additional economic return in agri-horticulture system. Among the shrubs, the 6 shrub species were recorded on the northern aspect whereas there number was 16 on southern aspect. The agricultural crop diversity was higher on the northern aspect in summer and winter season. The average annual productivity of grain under agri-horticulture system recorded 1106 kg·ha–1·year–1 on northern aspect and 1122 kg·ha–1·year–1 on southern with a reduction of 34.56% and 38.29% compared to the sole agriculture crops. The aspect and season also played significantly role in grain, straw and biological productivity of agricultural crops present in agri-horticulture and sole cropping systems. In general there was reduction in yield of agricultural crops under fruit trees but this reduction is supplemented by fruit production which support and sustain the rural community of this hilly region.

Species Composition, Richness and Diversity in Miombo Woodland of Bereku Forest Reserve, Tanzania

There is increased interest in the academic world with regards to tree and shrub species richness and diversity within the Miombo Woodlands and to determine the potential for biodiversity conservation. This study assessed species richness, diversity, dominance and exploitation of tree and shrub in Bereku Forest Reserve. Plant inventory was carried out in 80 systematically selected sample plots. The information recorded includes: diameter at breast height, species name and frequency of regenerants. Analysis of inventory data was done by using Microsoft Excel. A total of 1 10 species belonging to 53 families were identified. Results showed Shannon-Wiener Index and Simpson Diversity Index of 4.27 and 0.043 respectively for the Miombo woodland of Bereku. Moreover, the findings in this study show mean stems density and mean total density of regenerants of 616 stems per hectare and 2780 stems per hectare respectively . The paper concludes that despite the Miombo Woodland providing products and services to the surrounding communities the woodland is still fairly stocked with high tree and shrub species diversity . The study recommends in-depth forest inventory, preparation of management plan and promotion of good governance in management of Bereku forest reserve.

Impact of the 2008 Wenchuan earthquake on biodiversity and giant panda habitat in Wolong Nature Reserve, China

AbstractNatural disasters such as earthquakes have profound effects on the earth's biodiversity. However, studies on immediate earthquake impacts are rarely conducted at fine scales due to logistical constraints. We conducted the first post‐earthquake field survey in Wolong Nature Reserve, Wenchuan, China, less than 1 year after it was hit by a magnitude 8.0 earthquake in 2008. Since Wolong harbors approximately 10% of the endangered wild giant panda (Ailuropoda melanoleuca) population, the impact of the earthquake on the giant panda and its habitat is of particular concern. We established 15 transects in three focus areas within the Reserve where we classified occurrences of earthquake damage according to vegetation and geophysical characteristics. In the 11.2 km2 area sampled, we recorded 156 occurrences of earthquake damage consisting of landslides and mudflows, which comprised a total area of 0.88 km2. Of all earthquake damage occurrences sampled, only 36% of occurences (73% of surface area) corresponded to damaged areas previously detected through broad‐scale remote sensing. The remaining damaged areas mainly consisted of occurrences too small to be detected without field observation. Although there were significant losses to tree and shrub species diversity and richness in earthquake‐damaged areas, remnant vegetation was found in the majority (80%) of damaged areas, suggesting the potential for forest recovery. Most earthquake‐damaged areas were too steep to be classified as suitable giant panda habitat (79%). In addition, a sizable number of signs of giant panda (67) and other wildlife (148) were observed near the earthquake‐damaged areas, and there appeared to be avoidance of earthquake damage only at short‐range distances. This study has implications for understanding the impact of natural disasters on biodiversity and highlights the importance of fine scale on‐the‐ground assessments of disaster impacts on wildlife and their habitats.

Changes in traits of shrub canopies across an aridity gradient in northern Patagonia, Argentina

Low and highly variable precipitation pulses exert a strong selective pressure on plant traits and this might provide axes of ecological differentiation among plant species in arid ecosystems. We asked whether aridity contributes to maintain high diversity of species and morphotypes in shrub canopies. We selected eleven study sites evenly distributed across a 400-km transect in northern Patagonia, Argentina. Precipitation is low and highly variable within and between years but almost homogeneous across the transect (125–150 mm). Mean annual temperature varied, however, ranging from 8 °C (west) to 13.5 °C (east) creating a west–east gradient of aridity (aridity index from 3.7 to 7.3, respectively). Sheep grazing commenced in the early 1900s at a similar intensity across the transect. We recorded the richness and cover of shrubs by species and by morphotypes (drought deciduous tall shrubs, evergreen tall shrubs, medium shrubs, and dwarf shrubs), and further calculated the species and morphotype Shannon diversity index at each site. We assessed the presence of spiny leaves, leaf pubescence, thorny stems, and photosynthetic stems in shrub species of all morphotypes and collected green leaves of the dominant shrub species (more than 80% of the total shrub cover) to assess the leaf area, leaf mass per unit area, N-, lignin- and soluble phenolic-concentrations per species at each site. Richness and diversity of shrub species and morphotypes were positively associated with aridity. The richness and diversity of shrub species with pubescent leaves and thorny stems, and nitrogen concentration in green leaves of dominant shrubs increased with increasing aridity. We conclude that our findings on increased diversification in life history traits, species and morhotypes in shrub canopies with increasing aridity support the hypothesis that variability in aridity provides axes of ecological differentiation among shrub species facilitating their coexistence.

Taxonomic Diversity, Distinctness, and Abundance of Tree and Shrub Species in Kasagala Forest Reserve in Uganda: Implications for Management and Conservation Policy Decisions

The successful management of natural resources requires access to adequate information on social, economic, ecological, and cultural changes in order to mitigate their impacts through conservation interventions. In most cases, such information is provided in the form of simple diversity indices, which may not predict the complex nature of species functioning in ecosystems. In this study, we used rank abundance, analysis of similarities (ANOSIM), similarity percentages (SIMPER), and taxonomic-diversity and distinctness indices to show the status of tree and shrub species in Kasagala forest reserve in central Uganda. Four 100 × 100 m plots were established in four vegetation strata of the strict nature reserve of the forest, and diameter at breast height (DBH) of trees and shrubs ≥ 5 cm measured. There was no significant difference in species abundance in the four vegetation strata (Kruskal Wallis H = 2.614, p = 0.453; ANOSIM: R = −0.334, p = 0.995). The taxonomic diversity and distinctness of the four vegetation types ranged between 2.414 and 2.786 while the taxonomic distinctness values ranged between 2.897 and 2.978. The taxonomic diversity of the forest is generally even, suggesting a homogeneous community. We suggest that the managers of the forest constitute a continuous monitoring program aimed at controlling the impact of anthropogenic factors, one of the main influences for such low taxonomic distinctness values observed for this forest.

National‐scale analyses of habitat associations of Marsh Tits Poecile palustris and Blue Tits Cyanistes caeruleus: two species with opposing population trends in Britain

Capsule Marsh Tits were strongly associated with both the amount and species diversity of woodland understorey; Blue Tits were associated with large trees and deadwood. Aims To gather quantitative information on the habitat requirements of Marsh Tits, in comparison with those of Blue Tits, across a large number of sites in England and Wales, and secondly to evaluate the range of habitat conditions likely to encourage the presence, and increase the abundance of, each species. Methods Counts of birds were made at each of 181 woods across England and Wales, and habitat data were collected from the same locations in each woodland. Marsh Tit and Blue Tit presence and abundance were related to habitat characteristics, interspecific competition and deer impact. Results Shrub cover and species diversity were important for the presence and abundance of Marsh Tits, across their geographical range in Britain. Blue Tits were associated with large trees and deadwood. Conclusion Our results support the hypothesis that changes in woodland management, leading to canopy closure and a decline in the understorey available, could have had an impact on Marsh Tits, and may have led to the observed population decline. These same changes were also consistent with population increase in Blue Tits.

Urbanization and riparian forest woody communities: Diversity, composition, and structure within a metropolitan landscape

Understanding how urban land-use structure contributes to the abundance and diversity of riparian woody species can inform management and conservation efforts. Yet, previous studies have focused on broad-scale (e.g., urban to exurban) land-use types and have not examined more local-scale changes in land use (e.g., the variation within “urban”), which could be important in urban areas. In this paper we examine how local-scale characteristics or fine-scale urban heterogeneity affect(s) the diversity, composition, and structure of temperate woody riparian vegetation communities in the highly urbanized area of Cincinnati, Ohio, USA. We use an information-theoretic approach to compare vegetation models and canonical correspondence analyses to compare species responses to urban variables. We found that urban riparian areas can harbor a high diversity of native canopy and shrub species (38 and 41, respectively); however, native and exotic woody plant species responded differently to urbanization. Exotic canopy species increased with the level of urbanization while native canopy and understory species declined. Understory species diversity displayed a greater response to urbanization than did canopy diversity, suggesting temporal lags in canopy response to disturbances associated with present and recent land-use changes. Certain native and exotic woody species represent ecological indicators of different levels of urbanization. Native species characteristic of pre-European settlement conditions were restricted to the wide riparian forests with little urban encroachment. Several native early-successional species appear tolerant to urbanization. Two exotic species, the tree Ailanthus altissima and the shrub Lonicera maackii, were the most abundant and ubiquitous woody species and appear to exploit urban disturbances. These exotic species invasions have the potential to modify forest composition and ecological function of urban riparian systems. In addition, altered hydrology may be a contributing factor as canopy and understory stem density of high-moisture-requiring species decreased with an increase in impervious surface and grass cover and with proximity to roads and railroads. In the face of urbanization, maintaining wide riparian forests and limiting building, road and railroad development within these areas may help reduce the invasion of exotic species and benefit hydrological function in temperate riparian areas.

Ecological Factors Influencing Nest Survival of Greater Sage‐Grouse in Mono County, California

ABSTRACT We studied nest survival of greater sage‐grouse (Centrocercus urophasianus) in 5 subareas of Mono County, California, USA, from 2003 to 2005 to 1) evaluate the importance of key vegetation variables for nest success, and 2) to compare nest success in this population with other greater sage‐grouse populations. We captured and radiotracked females (n = 72) to identify nest sites and monitor nest survival. We measured vegetation at nest sites and within a 10‐m radius around each nest to evaluate possible vegetation factors influencing nest survival. We estimated daily nest survival and the effect of explanatory variables on daily nest survival using nest‐survival models in Program MARK. We assessed effects on daily nest survival of total, sagebrush (Artemisia spp.), and nonsagebrush live shrub‐cover, Robel visual obstruction, the mean of grass residual height and grass residual cover measurements within 10 m of the nest shrub, and area of the shrub, shrub height, and shrub type at the nest site itself. Assuming a 38‐day exposure period, we estimated nest survival at 43.4%, with percent cover of shrubs other than sagebrush as the variable most related to nest survival. Nest survival increased with increasing cover of shrubs other than sagebrush. Also, daily nest survival decreased with nest age, and there was considerable variation in nest survival among the 5 subareas. Our results indicate that greater shrub cover and a diversity of shrub species within sagebrush habitats may be more important to sage‐grouse nest success in Mono County than has been reported elsewhere.

The Response of Understory Species Composition, Diversity, and Seedling Regeneration to Repeated Burning in Southern Appalachian Oak-Hickory Forests

ABSTRACT: Understory plant composition and diversity levels in oak-hickory (Quercus-Carya) forests have historically been maintained by periodic low-intensity ground fires, but fire suppression has altered the structure and function of these communities. We examined burned and unburned oak-hickory stands to determine the influence of repeated burning on understory communities. We compared understory herbaceous, shrub, and tree species diversity and composition among four burn categories: unburned stands, and stands that had burned once, twice, and three times over a 20-year period (late 1960s to late 1980s). We hypothesized that stands that have received repeated burns will have greater understory diversity and reduced importance of shade-tolerant mesophytic species. We found that burned stands had greater species richness than unburned stands, regardless of burn frequency. Species composition was not drastically different among the four burn categories; however, individual species were indicative of part...

Vegetational analysis in mixed Banj (Quercus leucotrichophora A. Camus) - Tilonj Oak (Quercus Floribunda Lindl.) forests in Nainital Catchment

The present study was carried out on six forest sites dominated by Quercus leucotrichophora and Q. floribunda forests to assess variations in floral biodiversity and community with changes in microclimatic conditions between 2090 and 2200 m elevation in Nainital on 3 different aspects. The composition of tree layer was more or less similar across the studied sites. The impact of aspect change on shrub and herb species diversity and density was also insignificant possibly because of little change in altitude and canopy cover (above 70%) in the studied sites.