Shrub Species Richness Research Articles

Can a fast-growing early-successional tree (Ochroma pyramidale, Malvaceae) accelerate forest succession?

Abstract:Species-specific traits of trees affect ecosystem dynamics, defining forest structure and understorey development. Ochroma pyramidale is a fast-growing tree species, with life-history traits that include low wood density, short-lived large leaves and a narrow open thin crown. We evaluated forest succession in O. pyramidale-dominated secondary forests, diverse secondary forests, both 10–15 y since abandonment, and rain forests by comparing height, density and basal area of all trees (> 5 cm dbh). Furthermore, we compared species richness of understorey trees and shrubs, and basal area and density of trees of early- and late-successional species (< 5 cm dbh) between forest types. We found that tree basal area (mean ± SD: 32 ± 0.9 m2 ha−1) and height (12.4 ± 1.8 m) of canopy trees were higher, and density (1450 ± 339 ha−1) lower in O. pyramidale forests than in diverse forests, and more similar to rain forest. Understorey shrub diversity and tree seedling density and diversity were lower in O. pyramidale forests than in diverse forests, but these forest types had a similar density of early- and late-successional trees. Canopy openness (> 15%) and leaf litter (> 10 cm) were both highest in O. pyramidale forests, which positively affected density of understorey trees and shrubs and negatively affected density of late-successional trees. In conclusion, O. pyramidale forests presented structural features similar to those of rain forest, but this constrained the establishment of understorey tree species, especially late-successional species, decreasing successional development.

Vegetation structure along urban ephemeral streams in southeastern Arizona

Riparian areas in Arizona are being encroached upon by urban developments. This study investigated the impacts of different urban housing densities on riparian vegetation structure along ephemeral streams. Nine sites representing three levels of housing density were selected within the town of Marana, located in southeast Arizona. The housing densities were categorized as high (7–8 houses ha−1), moderate (2.5–4.5 houses ha−1), and low (< 1.5 houses ha−1). Each treatment had three replications. The urban developments were relatively young (less than 15 years). No significant differences were found among the treatments for the tree variables (density, height, mean canopy volume and total canopy volume) or the herbaceous vegetation variables (species richness, percentage of introduced species and percentage of ground cover). However, the shrub variables (mean density, mean height, mean canopy volume, total canopy volume and species richness) showed some significant differences. Shrub density and species richness was significantly greater adjacent to ephemeral channels than just three meters upland. In addition, whitethorn acacia shrubs were significantly taller and larger adjacent to the stream channels in the high and moderate housing density sites than in the low housing density sites. Creosote shrubs showed the opposite trend. Increased runoff in the more heavily urbanized streams may have promoted the growth of the facultative riparian species (whitethorn acacia) but not the non-riparian species (creosote). Overall, in these young developments, vegetation was resilient across the levels of urbanization explored in the study.

Alpine road colonisation: An update

SummaryA wide road verge on the Bogong High Plains near Falls Creek (north‐eastern Victoria), stabilised with exotic species in the late 1950s, was monitored for species composition and cover between 1989 and 2010. Following the removal of cattle grazing in 1991, the cover and species richness of native shrubs, forbs and grasses increased on the verge. Changes were initially slow, but by 1999, they were profound. The cover of exotic species decreased over the same period, but the species richness of exotic species remained unchanged. A wildfire in 2003 did not alter the trajectories of change. Although native species are proving to be competitive, the exotic rhizomic grass Brown‐top Bent (Agrostis capillaris) has been very persistent and is still locally dominant. Feral horses and rabbits are future threats to the continued colonisation by native species.

The interplay among grazing history, plant-plant spatial interactions and species traits affects vegetation recovery processes in Patagonian steppe

Since the early 20th century Patagonian arid steppes have been subjected to overgrazing that led to the degradation of plant communities. We hypothesized that the interplay among grazing history, plant-plant spatial interactions and species traits affects recovery and assemblage of shrub community after short-term abandonment in north-eastern Patagonian arid steppe (Peninsula Valdes, Argentina). We compared six sites (two in grazed pastures, and four in short-term ungrazed pastures, two of which intensively grazed, while the other two low intensity grazed in the past) with regard to: shrub cover percentage (10 × 10 m plots); shrub patch dimension, species richness, and spatial interactions among shrub species depending on patch dimension (patches sampled along transects); species richness and composition, vertical relations among species, and traits related to avoidance strategies and disturbance (1 × 1 m plots sampled along transects). Our results indicated that recovery processes in abandoned pastures a...

Interactions between overstorey and understorey vegetation along an overstorey compositional gradient

AbstractQuestionsWhat is the nature of the interactions between higher vegetation strata (overstorey) and lower strata (understorey vegetation) and among understorey vegetation layers in closed canopy forests? How does the abundance or richness of one vegetation layer affect the abundance or richness of the other?LocationBoreal mixed‐wood forests ofOntario andQuebec,Canada.MethodsWe sampled fire‐origin stands of varying overstorey composition from broad‐leaf‐dominated to mixed to conifer‐dominated stands on mesic sites inOntario and subhydric sites inQuebec. Overstorey tree species composition and understorey shrub, herb, bryophyte and lichen species cover and richness were estimated within 400‐m2circular plots. In addition, soil nutrients, coarse woody debris and light conditions were measured. Overstorey composition was expressed as the percentage basal area of broad‐leaf tree species. Path analysis was used to examine interactions among the forest layers.ResultsOverstorey broad‐leaf composition had positive effects on shrub and herb layer cover and herb layer richness, and negative effects on bryophyte and lichen species cover and richness. Shrub layer cover had no effect on herb layer cover, but shrub layer richness had a positive effect on herb layer richness. Herb layer cover and richness had negative effects on bryophyte species cover and richness. Bryophyte cover had no effect on lichen cover, but its richness was positively related to lichen richness. In both regions, soil pH, total nitrogen, total phosphorus and cation exchange capacity of the forest floor were positively correlated with overstorey broad‐leaf composition and with shrub layer cover and herb layer cover.ConclusionsIncreasing overstorey broad‐leaf composition, through its influence on soil nutrients, promotes shrub and herb layer species, but limits bryophyte and lichen species. In the overstorey‐controlled understorey resource environment, cover and richness of shrub and herb layers increase with resource availability, whereas bryophytes and lichens show positive associations with abundance of coarse woody debris.

LONG‐TERM VEGETATION DYNAMICS AFTER HIGH‐DENSITY SEEDLING ESTABLISHMENT: IMPLICATIONS FOR RIPARIAN RESTORATION AND MANAGEMENT

ABSTRACTHuman disturbances have contributed to the deterioration of many western US rivers in the past century. Cottonwood‐willow communities, present historically along the Colorado River, protect watersheds and provide wildlife habitat, but are now among the most threatened forests. As a result, restoration efforts have increased to re‐establish and maintain cottonwood‐willow stands. While successful establishment has been observed using multiple strategies with varying investments, few projects are evaluated to quantify efficacy and determine long‐term sustainability. We monitored a seeded cottonwood‐willow site over a five‐year period beginning in 2007, with particular interest in how density affected vegetation diversity and stand structure over time. Fremont cottonwood (Populus fremontii) and volunteer tamarisk (Tamarix ramosissma) were the only abundant riparian trees at the site after one year. P. fremontii, compared to T. ramosissma, had higher growth rates, lower mortality, and dominated overstory and total cover each year. Vegetation diversity decreased from 2007–2009, but was similar from 2009–2011 as a result of decreased herbaceous and increased shrub species richness. Diversity was highest in the lowest density class (1‐12 stems/m2), but similar among all other classes (13–24, 25–42, 43+). High initial woody species densities resulted in single‐stemmed trees with depressed terminal and radial growths. Allometry, relating height to DBH at different densities, could prove to be an important tool for long‐term restoration management and studying habitat suitability. Understanding long‐term trends at densely‐planted or seeded sites can benefit restoration managers who aim to establish specific community structure and vegetation diversity for wildlife habitat. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Woody flora of Uruguay: inventory and implication within the Pampean region

Adequate knowledge of a flora is fundamental for furthering research in several disciplines. In this context, our work arises from the necessity to update and improve available information on the native woody flora of Uruguay. The goals of this study were to objectively determine the Uruguayan native woody flora (shrub and trees), to evaluate its inventory completeness, and to explore its similarity with neighboring regions. By analyzing the Uruguayan flora we produced working definitions of shrubs and trees, and obtained a list of 313 species (57 families, 125 genera). Using 7418 distribution records, we generated cumulative species richness curves to estimate maximum species richness at national and local scales. We conclude that the completeness at the national level is high (89-95%), but at the local scale is lower and quite heterogeneous. There are still large areas without data or with little information. We found that comparatively, the similarity between Uruguayan tree species and the Province of Entre Ríos (Argentina) was high, while similarity with the Province of Buenos Aires (Argentina) was medium, and with Rio Grande do Sul (Brazil) was low. In conclusion, richness of tree and shrub species of the Uruguayan flora is greater than expected for a grassland region, and the differences found in the similarity index with the neighboring woody floras will stimulate future studies to reevaluate phytogeographic schemes of the region.

Effect of three georges reservoir (Yangzi River) on the plant species richness in drawdown zone downstream the tributary river (Pengxihe River)

In order to understand the spatial pattern of plant community and the maintenance mechanism of biodiversity in littoral zone of Three Gorges Reservoir, 110 km stretches of Pengxihe River (from estuary to the backwater of Three Gorges) were chose to study. We investigated species composition and environmental variables along 50 m long stretches of riverbank between the high-water level and the lowest summer water level, at a 5 km interval. The results showed that: (1) along longitudinal gradients, longitudinal species richness, longitudinal shrub species richness and longitudinal herb species richness were significantly related to distance to estuary; (2) along lateral gradient, there were visible different changes in all kinds of types (lateral species richness, lateral tree species richness, lateral shrub species richness, lateral herb species richness). Along lateral gradient, species richness and herb species richness first increased with the elevation then reduced with it, trees and shrubs species richness increased with the elevation. (3) Correlation analyses showed that substrate types were correlated with the longitudinal species richness, without considering the distance to estuary. Soil moisture and substrate heterogeneity were correlated with lateral, species richness. These results indicated that, along longitudinal gradient of the river, distance to estuary plays an important role in species richness, and along lateral gradient spatial heterogeneity due to inundation and flooding plays an important role in forming a new pattern of plant community in the littoral zone of Three Gorges Reservoir Region. Because of special hydrological dynamics, plant in the littoral zone of Three Gorges, are gradually form a unique spatial pattern to some extent, though it had the same change law with riparian plant of a natural river.

An 11‐yr exclosure experiment in a high‐elevation island ecosystem: introduced herbivore impact on shrub species richness, seedling recruitment and population dynamics

AbstractQuestionsDo introduced herbivores and fire explain the mono‐dominance of one legume shrub (Adenocarpus viscosus subsp. spartioides) above the tree line on an oceanic island, given the fact that a number of other legume shrub species are potentially present? What drives the observed landscape‐scale life–death pattern within the mono‐dominant shrub species population?LocationThe sub‐alpine scrub vegetation of La Palma (Canary Islands, Atlantic Ocean).MethodsAn 11‐yr exclosure experiment with sites distributed along an elevation and orientation gradient was used to identify the influence of introduced herbivore pressure on four endemic shrub species and their seedling recruitment. Further, we assessed the population dynamics and spatial pattern of the dominant shrub species A. viscosus subsp. spartioides. Habitat and vitality characteristics were investigated, assessing spatial topographic features and tree ring‐based age estimates. Linear mixed models, ANOVAs, linear regression and variation partitioning were used as statistical analysis tools.ResultsOutside of the exclosures A. viscosus subsp. spartioides was virtually mono‐dominant in the study area, even though other shrub species seem better suited in the absence of introduced herbivores. The presence of introduced herbivores significantly reduced seedling recruitment within all target species, except for A. viscosus subsp. spartioides. Mean age of A. viscosus subsp. spartioides increased with elevation, although vitality analyses indicated that the sub‐alpine scrub is elevated above its growth optimum. Three out of four investigated shrub species showed differences in growth height depending on elevation and island orientation.ConclusionIntroduced herbivores and fire are identified as key disturbances enhancing the occurrence of A. viscosus subsp. spartioides, a commonly less competitive species. However, Genista benehoavensis, a single island endemic shrub species, seems to be better adapted to the harsh climate conditions of the sub‐alpine scrub in the absence of introduced herbivores than any other shrub species.

Community Structure along Timberline Ecotone in Relation to Micro-topography and Disturbances in Western Himalaya

Four communities, formed as a result of locally varying site conditions, were identified and studied along the timberline ecotone in part of Kedarnath Wildlife Sanctuary (KWS). Communities on the vicinity of pilgrimage site and along gentler slopes were highly disturbed having sharp timberlines, while those located far and in the steep slopes were less affected, forming a little broader transition. The tree density ranged from 340 to 780 trees/ha, while the basal cover of communities varied greatly and ranged from 6.4 to 55.1 m 2 /ha. Birch dominated community had lowest basal area among all the communities, while mixed community had the highest. In all the respective communities, from subalpine zone, density and basal area was higher than that of timberline zone. The Importance Value Index (IVI), which used to determine the overall importance of each species in the community structure, of dominant species at timberline was more than 200 in all the communities, except in the mixed community. Influence of the anthropogenic disturbances was apparent on the regeneration performance of all the studied tree species. Rhododendron campanulatum was the dominant shrub species of the area and formed krummholz, while distribution of other species varies greatly with forest type. The shrub density decreased from high to low disturbance, while the herbaceous species density increased with prevalence of a few species favoring the high disturbance (grazing). The shrub and herb species richness was higher in the ecotone zone. Some uncommon species like Balanophora involucrata and Aralia cissifolia were also found at timberline. Three species of Lady’s Slipper orchid were reported together from Betula utilis community at timberline ecotone.

Comparison of Floristic Diversity between Young Conifer Plantations and Second-Growth Adjacent Forests in California's Northern Interior

There is concern that intensive even-aged forest management in conifer plantations has resulted in the decline of plant species diversity and contributed to the rise of invasive species in western forests. This 3-year study assessed plant species richness, composition of vascular plant species, and presence of rare and nonnative plant species in 73 survey units (2,528 ac) on industrial forestland in northern California. Survey units were evenly divided between conifer plantations and adjacent managed uneven-aged forests in three regions of northern California: Sierra Nevada, Southern Cascades, and Klamath Mountains. We surveyed two forest types within these regions: mixed conifer and true fir. There was no significant difference in species richness between plantations and adjacent forests. Plantations tended to be richer in forbs and graminoids, whereas forests were richer in trees and shrubs. Herbicide applications in plantations significantly reduced shrub species richness, but the effect was short-lived. Rare plant species were equally distributed between plantations and adjacent forests, but plantations contained one additional nonnative plant species. Overall, our findings demonstrate that managed, even-aged conifer plantations maintain plant species richness at a level similar to adjacent managed, uneven-aged forests.

Do eucalypt plantations provide habitat for native forest biodiversity?

Plantation forestry contributes to the economic growth of many regions, but may also produce ecological impacts (e.g. on biodiversity) that can be reduced with proper management. We assessed the value of eucalypt plantations to favor habitat connectivity at the landscape scale by determining their ability to provide habitat for species associated with the natural vegetation. For this purpose, we compared diversity and composition of understory vegetation in low-management eucalypt plantations in young, intermediate (ready for harvest) and mature stages with pine plantations, native forests and shrublands. We estimated the true species richness with Chao2 estimators and compared among habitats the average species richness (at two different local scales: per plot and per site), Shannon indices and biovolume of herbs, shrubs and trees in the understory using ANOVAs or GLZs, depending on data distributions. Differences among habitats in understory species composition and functional types were compared with PERMANOVA, and were graphically represented using NMDS ordinations. At local scales, diversity tended to be higher in native communities (native forests and shrublands) and lower in plantations (lowest in intermediate eucalypt plantations). Diversity across all study sites was again lowest in eucalypt plantations in intermediate age, but was relatively high in other plantations, due to a high species turnover in young and mature eucalypt plantations. Eucalypt plantations were similar to shrublands in understory species composition and functional types when young, becoming more distant to them when older, and more similar to pine plantations and native forests. Native forests were the most distinctive community, with pine plantations being the most similar to them. Native forests harbored the rarest species and were also associated with seed dispersal by vertebrates (internally). Ant- and wind dispersal were the most common in shrublands and eucalypt plantations. Given the prevalence of eucalypt plantations in some regions, determining (and improving, if feasible) their ability to harbor biodiversity of native communities becomes a crucial goal, in order to increase landscape connectivity and favor species persistence at regional scales. In the study region, eucalypt plantations provide habitat for species typical of shrublands when young but do not contribute significantly to the maintenance of the understory biodiversity associated with native forests. Considering the distinctiveness of native forests, we favor protection and, where feasible, restoration of native forests over managing eucalypt plantations for biodiversity to best improve conservation outcomes.

Changes in biodiversity indicators in managed and unmanaged forests in NE Spain

Major changes in Mediterranean forests have occurred in recent decades, mainly as a result of the abandonment of traditional activities and population decline in rural areas. In this study, we analyzed the short-term (11-year) evolution of forests in the region of Catalonia (NE Spain) and the role of management, by comparing seven biodiversity indicators estimated from 7,664 plots from the Second and Third Spanish National Forest Inventory. We evaluated the changes in unmanaged and managed stands with different silvicultural treatments, and considered the effect of stand density and land ownership on these dynamics. We found a general naturalization and maturation of forests and an increase in all of the biodiversity indicators investigated during the study period, with the increments being greater in unmanaged than in managed plots. Some types of silvicultural treatments, such as selection cutting or thinning, were shown to be compatible with an increase in the analyzed indicators, and thus were more adequate for a multifunctional management that considers forest production together with the maintenance or improvement of the diversity of forest communities. The increases in shrub species richness and in the number of large-diameter trees after silvicultural treatments were more prominent in dense stands. Private lands presented greater short-term increases than public forests in all biodiversity indicators, except for large-diameter trees. From these results, we concluded that the application of silvicultural treatments can be a key tool to shape and maintain diverse and healthy forest structures in the context of socioeconomic and environmental changes in the Mediterranean region, which may induce potentially excessive densification and homogenization of some forest stands and landscapes.

STRUCTURE OF TWO COMMUNITIES DOMINATED BY COPERNICIA ALBA AND ASSOCIATIONS WITH SOIL AND INUNDATION IN PANTANAL WETLAND, BRAZIL

Known for its high degree of biodiversity, the tropics have a number of sites in which one or few species dominate large areas, as occurs in the Pantanal wetland, Brazil, with the ‘carandá' palm, Copernicia alba, in monodominant formations known regionally as ‘carandazal'. The aim of the present study was to analyze variations in species richness and diversity of herbs, shrubs and trees in two communities dominated by Copernicia albawith different flood patterns and determine whether soil fertility and time of inundation are associated with tree/shrub species composition and abundance. Vegetation was analyzed in 50 plots measuring 100m 2 in each area, with the determination of the tree/shrub component (CBH ? 5cm). Three subplots measuring 1m 2 were demarcated within each plot for the sampling of herbs, sub-shrubs, shrubs (CBH 2 plot. Associations between soil data, time of inundation and absolute density of tree/shrub vegetation were tested using canonical correspondence analysis (CCA). For the tree/shrub component, a total of 22 species belonging to 12 families were sampled in the two communities. Richness was greater in the area submitted to a lesser time of inundation. Copernicia albahad the greatest importance values in both study areas, followed by Tabebuia aureain one community and Mimosa glutinosain the other. In the subplots, 178 species belonging to 39 families were sampled, for which Fabaceae, Poaceae, Asteraceae and Cyperaceae figured prominently. The herbaceous component predominated over the others in species richness in both areas, but similarity was low. CCA detected associations between soil fertility, time of inundation and composition of tree/shrub species. The richness of the tree/shrub component was greater in the area with a shorter inundation time, which makes this event an important factor in the determination of C. albamonodominance in the Pantanal wetland. The herbaceous component demonstrated a high degree of richness and diversity in both communities, although there are differences in the inundation pattern between the two areas.

Grazing effects on plant functional group diversity in Mediterranean shrublands

Grazing is one of the prevalent human activities that even today are taking place inside protected areas with direct or indirect effects on ecosystems. In this study we analyzed the effects of grazing on plant species diversity, plant functional group (PFG) diversity and community composition of shrublands. We analyzed plant diversity data from 582 sampling plots located in 66 protected areas of the Greek Natura 2000 network, containing in total 1102 plant species and subspecies. We also classified a priori all plant species in seven PFGs: annual forbs, annual grasses/sedges, legumes, perennial forbs, perennial grasses/sedges, small shrubs and tall shrubs. For each site, grazing intensity was estimated in four classes (no grazing, low, medium and high grazing intensity). We found that, at the spatial and temporal scale of this study, as grazing intensity increased, so did total species richness. However, each PFG displayed a different response to grazing. Short-lived species (annual grasses or forbs and legumes) benefited from grazing and their species richness and proportion in the community increased with grazing. Perennial grasses and forbs species richness increased with grazing intensity, but their dominance decreased, since their proportion in the community declined. Short shrub species richness remained unaffected by grazing, while tall shrub diversity decreased. Finally, in sites without grazing the spatial pattern of species richness of the different PFGs was not congruent with each other, while in grazed sites they were significantly positively correlated (with the exception of tall shrubs). This finding may imply that grazing is a selective pressure organizing the community structure, and imposing a certain contribution of each PFG. So, in Mediterranean shrublands in protected areas with a long historical record of grazing, it seems that grazing promotes species diversity and its continuation on a portion of the landscape may be a necessary part of an effective management plan.

Recovery of Plant Species Richness and Composition in an Abandoned Forest Settlement Area in Kenya

Cultivation of annual crops in the initial stage of reforestation has been commonly practiced in the tropics. In recent decades, however, cultivation of such areas has been discontinued, resulting in widespread abandoned settlements. In this article we used a former forest village settlement in Kenya, which had been cleared, cultivated and then abandoned, to study how natural vegetation recovers after such disturbances. Species richness, abundance, and composition of tree seedlings, saplings, adult trees, shrubs, and herbs were recorded in different zones, from a heavily degraded zone in the center of the settlement, through less disturbed transition zones (TZs), and in the surrounding secondary forest (SF). Species richness and abundance of tree seedlings, saplings, and adult trees increased gradually from the heavily degraded zone to the SF, whereas shrub and herb richness were the same for TZs and SF and abundance was lowest in the SF. Total species richness was highest in the SF. Some pioneer tree species were highly associated with the TZs, whereas sub‐canopy tree species were associated with the SF. A group of tree species were not particularly associated with any of the four zones. Thus, these species might have good potential as restoration species. The results of our study contribute to the knowledge of natural regeneration in general, and of individual species characterizing the different stages of recovery of abandoned settlements in particular. Such information is urgently needed in designing ecologically sound management strategies for restoring abandoned forest settlements in tropical areas.

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.

Species richness of woody plants in the landscapes of Central Spain: the role of management disturbances, environment and non-stationarity

Questions: How important is management disturbance on gamma species richness of woody plants at intermediate landscape scales? How is species richness related to other climatic and biotic factors in the study area? How does the assumption of spatial stationarity affect assessment of relationships among species richness and explanatory variables (e.g. management, biotic and climatic factors) across extensive study areas? Location: Central Spain (regions of Castilla y León, Madrid and Castilla-La Mancha). Scale: Extent: 150 000 km2. Grain: 25 km2 (5 × 5-km cells). Methods: Information from 21 064 plots from the 3SNFI was used to evaluate richness of tree and shrub species at intermediate landscape scales. In addition to variables well known to explain biodiversity, e.g. environmental and biotic factors, effect of management treatments was evaluated by assessing clearcutting, selection cutting, stand improvement treatments and agrosilvopastoral systems (dehesas). Results from GWR techniques were compared with those from OLS regression. Results: Patterns of gamma species richness, although strongly affected by both environmental and biotic variables, were also significantly modified by management factors. Species richness increased with percentage of selection cutting stands and improvement treatments but decreased with percentage of clearcutting stands. Reduced species richness of woody plants was associated with agrosilvopastoral practices. Species richness for trees was closely related to basal area, annual precipitation and topographic complexity; species richness for shrubs was closely related to topographic complexity and agrosilvopastoral systems. Most relationships between species richness and environmental or biotic factors were non-stationary. Relationships between species richness and management effects tended to be stationary, with a few exceptions. Conclusions: Landscape models of biodiversity in Central Spain were more informative when they accounted for effects of management practices, at least at intermediate scales. In the context of current rural abandonment, silvicultural disturbances of intermediate intensity increased gamma species richness of woody plants. Exclusion of factors such as agrosilvopastoral systems from models could have led to spurious relationships with other spatially co-varying factors (e.g. summer precipitation). Patterns of spatial variation in relationships, provided by GWR models, allowed formulating hypotheses about potential ecological processes underlying them, beyond generalizations resulting from global (OLS) models.

Consequences of Buffelgrass Pasture Development for Primary Productivity, Perennial Plant Richness, and Vegetation Structure in the Drylands of Sonora, Mexico

In large parts of northern Mexico native plant communities are being converted to non-native buffelgrass (Pennisetum ciliare) pastures, and this conversion could fundamentally alter primary productivity and species richness. In Sonora, Mexico land conversion is occurring at a regional scale along a rainfall-driven gradient of primary productivity, across which native plant communities transition from desert scrub to thorn scrub. We used a paired sampling design to compare a satellite-derived index of primary productivity, richness of perennial plant species, and canopy-height profiles of native plant communities with buffelgrass pastures. We sampled species richness across a gradient of primary productivity in desert scrub and thorn scrub vegetation to examine the influence of site productivity on the outcomes of land conversion. We also examined the influence of pasture age on species richness of perennial plants. Index values of primary productivity were lower in buffelgrass pastures than in native vegetation, which suggests a reduction in primary productivity. Land conversion reduced species richness by approximately 50% at local and regional scales, reduced tree and shrub cover by 78%, and reduced canopy height. Land conversion disproportionately reduced shrub species richness, which reflects the common practice among Sonoran ranchers of conserving certain tree and cactus species. Site productivity did not affect the outcomes of land conversion. The age of a buffelgrass pasture was unrelated to species richness within the pasture, which suggests that passive recovery of species richness to preconversion levels is unlikely. Our findings demonstrate that land conversion can result in large losses of plant species richness at local and regional scales and in substantial changes to primary productivity and vegetation structure, which casts doubt on the feasibility of restoring native plant communities without active intervention on the part of land managers.