Herpetofaunal Responses to Restoration Treatments of Longleaf Pine Sandhills in Florida

The hypothesis that habitat restoration will provide for community reestablishment and the creation of habitat heterogeneity was examined with regards to the herpetofauna of longleaf pine sandhills in northwest Florida. The herpetofaunal response to restoration was examined in fire‐suppressed, hardwood‐dominated areas treated with (1) spring fire; (2) felling or girdling; or (3) a granular form of the herbicide hexazinone. No‐treatment controls were also included. Felling or girdling and herbicide plots were burned for fuel reduction two dormant seasons after initial treatment application. Additionally, data were collected in frequently burned reference sandhills to establish the target condition or restoration goal. Vegetation variables and herpetofaunal capture rates were compared among control and treatment areas. Two similarity indices were utilized to compare treatments and controls with reference sites, to examine restoration success. Restoration treatment effects were observed through reduced hardwood densities. Litter composition varied among control and treatment plots, with leaf litter being highest in areas lacking recent fire. Capture rates of some herpetofaunal species varied significantly among treatment plots. In 1997 similarity indices showed that spring‐burned and felling or girdling plots were more similar to the reference sandhills than the other plots. Treated plots were not significantly different from controls in 1998, a year of a severe drought.     

Post‐fire succession and 20th century reduction in fire frequency on xeric southern Appalachian sites

Abstract. We document post‐fire succession on xeric sites in the southern Appalachian Mountains, USA and assess effects of 20th century reduction in fire frequency on vegetation structure and composition. Successional studies over 18 yr on permanent plots that had burned in 1976–1977 indicate that tree mortality and vegetation response varied with fuel load and fire season. In the first three years after fire, hardwood sprouts dominated tree regeneration. On sites where summer and autumn fires reduced litter depth to less than 1 cm, densities of shade‐intolerant Pinus seedlings increased steadily over this period. 4 to 8 yr after fire, large numbers of newly established seedlings and sprouts had grown to 1 – 10 cm DBH. By year 18 growth of these saplings led to canopy closure on most sites. Herbaceous cover and richness peaked in the first decade after fire, then declined. On similar sites that had not burned in more than 50 yr, regeneration of shade‐intolerant Pinus spp. and mean cover and richness of herbs were considerably lower than those observed on recently burned plots. Reconstructions of landscape conditions based on observed post‐fire succession and 20th century changes in fire regime suggest that reductions in fire frequency circa 1940 led to substantial changes in forest structure and decreases in cover and richness of herbaceous species.     

Restoration of Northwest Florida Sandhills Through Harvest of Invasive Pinus clausa

Across much of the southeastern U.S.A., sandhills have become dominated by hardwoods or invasive pine species following logging of Pinus palustris (longleaf pine) and fire suppression. At Eglin Air Force Base where this study was conducted, Pinus clausa (sand pine) has densely colonized most southeastern sandhill sites, suppressing groundcover vegetation. The objectives of this study were: to determine if suppressed groundcover vegetation recovers following the removal of P. clausa; to compare species composition and abundance in removal plots with that in reference, high quality sandhills; to test the assumption that recolonization by P. clausa seedlings decreases with proximity to the centers of removal plots; and to measure the survival of containerized P. palustris seedlings that were planted on P. clausa removal plots. One year post‐removal (1995), the number of plant species decreased by 50%, but then increased by 100% from 1995 to 1997, followed by a small reduction in 1998. The number of plant species was greater in reference plots than in removal plots prior to 1997. Eighty‐five percent of the original species were recorded 4 years post‐harvest in removal plots. Shrubs and large trees remained at low density after harvest. Densities of graminoids, legumes, other forbs, woody vines, and small trees increased after harvest. Plant densities of all life forms, except woody vines, were greater in reference plots than in removal plots. The density of recolonizing P. clausa seedlings 2–4 years post‐harvest significantly decreased with increasing proximity to the centers of removal plots. On average, 80% of planted P. palustris seedlings survived their first 2 years. Harvest of P. clausa followed by fire and the planting of P. palustris is a reasonably effective restoration approach in invaded sandhills. However, supplementary plantings of some herbaceous species may be necessary for full restoration.     

Understory vegetation response to mechanical mastication and other fuels treatments in a ponderosa pine forest

Questions: What influence does mechanical mastication and other fuel treatments have on: (1) canopy and forest floor response variables that influence understory plant development; (2) initial understory vegetation cover, diversity, and composition; and (3) shrub and non‐native species density in a second‐growth ponderosa pine forest. Location: Challenge Experimental Forest, northern Sierra Nevada, California, USA. Methods: We compared the effects of mastication only, mastication with supplemental treatments (tilling and prescribed fire), hand removal, and a control on initial understory vegetation response using a randomized complete block experimental design. Each block (n=4) contained all five treatments and understory vegetation was surveyed within 0.04‐ha plots for each treatment. Results: While mastication alone and hand removal dramatically reduced the midstory vegetation, these treatments had little effect on understory richness compared with control. Prescribed fire after mastication increased native species richness by 150% (+6.0 species m²) compared with control. However, this also increased non‐native species richness (+0.8 species m²) and shrub seedling density (+24.7 stems m²). Mastication followed by tilling resulted in increased non‐native forb density (+0.7 stems m²). Conclusions: Mechanical mastication and hand removal treatments aided in reducing midstory fuels but did not increase understory plant diversity. The subsequent treatment of prescribed burning not only further reduced fire hazard, but also exposed mineral soil, which likely promoted native plant diversity. Some potential drawbacks to this treatment include an increase of non‐native species and stimulation of shrub seed germination, which could alter ecosystem functions and compromise fire hazard reduction in the long‐term.     

Gopher Tortoise Response to Habitat Management by Prescribed Burning

ABSTRACT As quality of forested habitat declines from altered fire regimes, gopher tortoises (Gopherus polyphemus) often move into ruderal areas to the detriment of the animal and land manager. We evaluated effects of a dormant-and-growing-season prescribed fire on habitat and gopher tortoise use of degraded longleaf pine (Pinus palustris) forests surrounding military training areas. We burned 4 of 8 sites in winter 2001–2002 and again in April 2003. Changes in vegetation measured during 2001–2004 indicated that burn treatments did not increase herbaceous vegetation. Similarly, movement patterns, burrow usage, and home range of tortoises radiotracked from 2002–2004 did not differ between treatments. Woody cover initially was reduced in the forests postburn, and we found more new burrows in burned forest sites. Once shrub cover was reduced, tortoises started using forested habitat that had become overgrown. However, shrub reduction may be temporary, as woody stem densities increased postburn. Thus, the one-time use of fire to manage tortoise habitat may not rapidly restore the open canopy, sparse woody midstory, and abundant herbaceous vegetation that this species requires. Repeated prescribed fires or additional management techniques may be needed for complete restoration.     

Native and naturalized plant diversity are positively correlated in scrub communities of California and Chile

Abstract. An emerging body of literature suggests that the richness of native and naturalized plant species are often positively correlated. It is unclear, however, whether this relationship is robust across spatial scales, and how a disturbance regime may affect it. Here, I examine the relationships of both richness and abundance between native and naturalized species of plants in two mediterranean scrub communities: coastal sage scrub (CSS) in California and xeric-sloped matorral (XSM) in Chile. In each vegetation type I surveyed multiple sites, where I identified vascular plant species and estimated their relative cover. Herbaceous species richness was higher in XSM, while cover of woody species was higher in CSS, where woody species have a strong impact upon herbaceous species. As there were few naturalized species with a woody growth form, the analyses performed here relate primarily to herbaceous species. Relationships between the herbaceous cover of native and naturalized species were not significant in CSS, but were nearly significant in XSM. The herbaceous species richness of native and naturalized plants were not significantly correlated on sites that had burned less than one year prior to sampling in CSS, and too few sites were available to examine this relationship in XSM. In post 1-year burn sites, however, herbaceous richness of native and naturalized species were positively correlated in both CSS and XSM. This relationship occurred at all spatial scales, from 400 m² to 1 m² plots. The consistency of this relationship in this study, together with its reported occurrence in the literature, suggests that this relationship may be general. Finally, the residuals from the correlations between native and naturalized species richness and cover, when plotted against site age (i.e. time since the last fire), show that richness and cover of naturalized species are strongly favoured on recently burned sites in XSM; this suggests that herbaceous species native to Chile are relatively poorly adapted to fire.     

Influence of Post‐Clearing Treatment on the Recovery of Herbaceous Plant Communities in Amazonian Secondary Forests

Secondary forests are an increasingly common feature in tropical landscapes worldwide and understanding their regeneration is necessary to design effective restoration strategies. It has previously been shown that the woody species community in secondary forests can follow different successional pathways according to the nature of past human activities in the area, yet little is known about patterns of herbaceous species diversity in secondary forests with different histories of land use. We compared the diversity and abundance of herbaceous plant communities in two types of Central Amazonian secondary forests—those regenerating on pastures created by felling and burning trees and those where trees were felled only. We also tested if plant density and species richness in secondary forests are related to proximity to primary forest. In comparison with primary forest sites, forests regenerating on non‐burned habitats had lower herbaceous plant density and species richness than those on burned ones. However, species composition and abundance in non‐burned stands were more similar to those of primary forest, whereas several secondary forest specialist species were found in burned stands. In both non‐burned and burned forests, distance from the forest edge was not related to herbaceous density and species richness. Overall, our results suggest that the natural regeneration of herbaceous species in secondary tropical forests is dependent on a site's post‐clearing treatment. We recommend evaluating the land history of a site prior to developing and implementing a restoration strategy, as this will influence the biological template on which restoration efforts are overlaid.     

Development of Brachystegia‐Julbernardia woodland after clear‐felling in central Zambia: Evidence for high resilience

Question: Does the development of Brachystegia‐Julbernardia (miombo) woodland after felling, and under a variable fire regime, occur via a serai stage of fire‐tolerant species? Location: Four sites in central Zambia, Africa. Methods: Trees in replicate plots were clear‐cut and stumps and resprouts enumerated. Species recruited into the tree layer (> 2.0 m tall) were monitored for 11 years (1991–2001) and fire occurrence and herbaceous biomass assessed annually to determine fuel loads. Results: Fire frequency was variable at the study sites and fuel loads were generally too low to suppress woodland regeneration after felling. However, at one site a change from low to high fire frequency arrested woodland development and triggered a regression towards a ‘fire‐trap’ vegetation type in which a few fire‐tolerant species survived. There was no evidence to support the hypothesis that miombo woodland regeneration is facilitated by a sere of fire‐tolerant species. All regrowth after felling was from resprouting plants present before felling. Trees with a previous history of felling sprouted more vigorously than trees that had not been felled before. Species richness in the tree layer increased with time since felling because resprout species had different height growth rates. Conclusion: The resilience of miombo trees after clear‐felling is largely due to their capacity to regenerate vegetatively from resprouts and stumps after release from frequent fires. Coppicing is therefore recommended as a suitable management technique for miombo woodland in central southern Africa.     

Effects of Prescribed Fire on Shinnery Oak ( Quercus havardii) Plant Communities in Western Oklahoma

Changes in structural and compositional attributes of shinnery oak (Quercus havardii Rydb.) plant communities have occurred in the twentieth century. These changes may in part relate to altered fire regimes. Our objective was to document effects of prescribed fire in fall (October), winter (February), and spring (April) on plant composition. Three study sites were located in western Oklahoma; each contained 12, 60 × 30‐m plots that were designated, within site, to be seasonally burned, annually burned, or left unburned. Growing season canopy cover for herbaceous and woody species was estimated in 1997–1998 (post‐treatment). At one year post‐fire, burning in any season reduced shrub cover, and spring burns reduced cover most. Winter and annual fires increased cover of rhizomatous tallgrasses, whereas burning in any season decreased little bluestem cover. Perennial forbs increased with fall and winter fire. Shrub stem density increased with fire in any season. Communities returned rapidly to pre‐burn composition with increasing time since fire. Fire effects on herbaceous vegetation appear to be manifested through increases in bare ground and reduction of overstory shrub dominance. Prescribed fire can be used as a tool in restoration efforts to increase or maintain within and between community plant diversity. Our data suggest that some plant species may require or benefit from fire in specific seasons. Additional research is needed to determine the long‐term effects of repeated fire over time.     

Productivity and species richness across an environmental gradient in a fire-dependent ecosystem

The fire-dependent longleaf pine-wiregrass (Pinus palustris Mill.-Aristida beyrichiana Trin. & Rupr.) savannas of the southeastern United States provide a unique opportunity to examine the relationship between productivity and species richness in a natural ecosystem because of the extremely high number of species and their range across a wide ecological amplitude (sandhills to edges of wetlands). We used a natural gradient to examine how plant species richness and plant community structure vary with standing crop biomass (which in this system is proportional to annual net productivity) as a function of soil moisture and nitrogen mineralization rates in a frequently burned longleaf pine-wiregrass savanna. Highest ground cover biomass and highest species richness were found at the same position along the gradient, the wet-mesic sites. Relative differences in species richness among site types were independent of scale, ranging from 0.01 m(2) to 100 m(2). Nitrogen availability was negatively correlated with species richness. Dominance of wiregrass (in terms of biomass) was consistent across the gradient and not correlated with species richness. Regardless of site type, the community structure of the savannas was characterized by many perennial species with infrequent occurrences, a factor in the low temporal heterogeneity (percent similarity between seasons and years) and high within-site spatial heterogeneity (percent dissimilarity of vegetation composition). The coexistence of numerous species is likely due to the high frequency of fire that removes competing hardwood vegetation and litter and to the suite of fire-adapted perennial species that, once established, are able to persist. Our results suggest that soil moisture is an important factor regulating both the number of species present and community production within the defined gradient of this study.     

Anthropogenic fires increase alien and native annual species in the Chilean coastal matorral

Aim We tested the hypothesis that anthropogenic fires favour the successful establishment of alien annual species to the detriment of natives in the Chilean coastal matorral. Location Valparaíso Region, central Chile. Methods We sampled seed rain, seedbank emergence and establishment of species in four paired burned and unburned areas and compared (using GLMM) fire resistance and propagule arrival of alien and native species. To assess the relative importance of seed dispersal and seedbank survival in explaining plant establishment after fire, we compared seed rain and seedbank structure with post‐fire vegetation using ordination analyses. Results Fire did not change the proportion of alien species in the coastal matorral. However, fire increased the number of annual species (natives and aliens) of which 87% were aliens. Fire reduced the alien seedbank and not the native seedbank, but alien species remained dominant in burned soil samples (66% of the total species richness). Seed rain was higher for alien annuals than for native annuals or perennials, thus contributing to their establishment after fire. Nevertheless, seed rain was less important than seedbank survival in explaining plant establishment in burned areas. Main conclusions Anthropogenic fires favoured alien and native annuals. Thus, fire did not increase the alien/native ratio but increased the richness of alien species. The successful establishment of alien annuals was attributable to their ability to maintain rich seedbanks in burned areas and to the greater propagule arrival compared to native species. The native seedbank also survived fire, indicating that the herbaceous community has become highly resilient after centuries of human disturbances. Our results demonstrate that fire is a relevant factor for the maintenance of alien‐dominated grasslands in the matorral and highlight the importance of considering the interactive effect of seed rain and seedbank survival to understand plant invasion patterns in fire‐prone ecosystems.     

Interaction of multiple disturbances: importance of disturbance interval in the effects of fire on rehabilitating mined areas

Abstract Multiple disturbance regimes are increasingly common as novel anthropogenic disturbances are added to existing natural disturbances. However, it is generally unknown whether simultaneous or sequential effects of different forms of disturbance are predictable from the independent effects of each disturbance. This study examines the short‐term effects of sequential disturbance by mineral sand‐mining followed by fire in a forest community in south‐eastern Australia. Four combinations of disturbance were sampled: unburned mined, burned mined, unburned forest (unmined) and burned forest (unmined, with between‐fire interval matching the disturbance interval between mining and fire of the burned mined treatment). All combinations were sampled approximately 12 months following fire on the burned sites. The impact of fire after mining depended on disturbance interval. Sites burned 0.5–2.4 years since mining had fewer native vascular plant species than unburned mined sites of the same mined age, whereas sites with 10–16 years or 20–26 years between mining and fire had greater native species richness than unburned mined sites of the same age. Burning 20–26 years after mining brought native species richness within the range of burned forest. For both unmined and mined sites native seedling densities increased with burning, and with longer disturbance intervals. Weed species richness and weed seedling densities were greater on mined sites than in forest, and burning mined sites elevated weed seedling densities further, particularly for short intervals. Both disturbance interval and fire intensity are likely to have contributed to these results, as intensity on mined areas increased with interval, and at 20–26 years post‐mining was equivalent to unmined forest. These results suggest that fire could be used to promote rehabilitation of these mined areas after at least 10 years, but should be excluded from earlier stages of post‐mining regeneration. However, other sources of spatial and temporal variability should be considered in addition to interval and intensity, as variation among mined areas was correlated with post‐fire weather conditions and available weed sources. Finally, the combined effects of mining and fire could not be predicted from knowledge of the disturbances operating separately, indicating that effects of multiple disturbance may be synergistic rather than additive.     

Effects of Fire on Seedling Diversity and Plant Reproduction (Sexual vs. Vegetative) in Neotropical Savannas Differing in Tree Density

Little is known about the effects of fire on the structure and species composition of Neotropical savanna seedling communities. Such effects are critical for predicting long‐term changes in plant distribution patterns in these ecosystems. We quantified richness and density of seedlings within 144 plots of 1 m² located along a topographic gradient in long‐unburned (fire protected since 1983) and recently burned (September 2005) savannas in Brazil. These savannas differ in tree density and canopy cover. Sites along the gradient, however, did not differ in species composition prior to the fire. In recently burned savannas we also evaluated the contribution of vegetative reproduction relative to sexual reproduction by quantifying richness and density of root suckers. Finally, we tested seed tolerance to pulses of high temperatures—similar to those occurring during fires on the soil surface and below—of five dominant savanna tree species. Seedlings were more abundant and diverse in unburned than in burned savannas. Seedling species composition differed among unburned and burned savannas probably reflecting early differences in root: shoot biomass allocation patterns. In recently burned savannas, root suckers were more abundant and diverse than seedlings. Relatively long exposures (>10 min) of temperatures of 90 °C reduced seed germination in all studied species suggesting a negative effect of fire on germination of seeds located at or aboveground level. Because vegetative reproduction contributes more than sexual reproduction in burned environments, frequent fires are likely to cause major shifts in species composition of Neotropical savanna plant communities, favoring clonally produced recruits along tree density/topographic gradients.     

Response of plant species and life form diversity to variable fire histories and biomass in the jarrah forest of south‐west Australia

Frequent fires reduce the abundance of woody plant species and favour herbaceous species. Plant species richness also tends to increase with decreasing vegetation biomass and cover due to reduced competition for light. We assessed the influence of variable fire histories and site biomass on the following diversity measures: woody and herbaceous species richness, overall species richness and evenness, and life form evenness (i.e. the relative abundance or dominance among six herbaceous and six woody plant life forms), across 16 mixed jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) forest stands in south‐west Australia. Fire frequency was defined as the total number of fires over a 30‐year period. Overall species richness and species evenness did not vary with fire frequency or biomass. However, there were more herbaceous species (particularly rushes, geophytes and herbs) where there were fewer shrubs and low biomass, suggesting that more herbaceous species coexist where dominance by shrubs is low. Frequently burnt plots also had lower number and abundance of shrub species. Life form evenness was also higher at both high fire frequency and low biomass sites. These results suggest that the impact of fire frequency and biomass on vegetation composition is mediated by local interactions among different life forms rather than among individual species. Our results demonstrate that measuring the variation in the relative diversity of different woody and herbaceous life forms is crucial to understanding the compositional response of forests and other structurally complex vegetation communities to changes in disturbance regime such as increased fire frequency.     

Response of Six‐Lined Racerunner (Aspidoscelis sexlineata) to Habitat Restoration in Fire‐Suppressed Longleaf Pine (Pinus palustris) Sandhills

Six‐lined racerunner (Aspidoscelis sexlineata) is an indicator species of frequently burned Longleaf pine (Pinus palustris) forests. To evaluate how the species responded to forest restoration, we conducted a mark‐recapture study in formerly fire‐suppressed Longleaf pine forests exposed to prescribed fire or fire surrogates (i.e. mechanical or herbicide‐facilitated hardwood removal) as well as in fire‐suppressed control sites and reference sites, which represented the historic condition. After initial treatment, all sites were exposed to over a decade of prescribed burning with an average return interval of approximately 2 years. We used population‐level response of A. sexlineata as an indicator of the effectiveness of the different treatments in restoring habitat. Specifically, we compared mean numbers of marked adults and juveniles at treatment sites to that of reference sites. After 4 years, restoration objectives were met at sites treated with burning alone and at sites treated with mechanical removal of hardwoods followed by fire. After over 10 years of prescribed burning, restoration objectives were met at all treatments. We conclude that prescribed burning alone was sufficient to restore fire‐suppressed Longleaf pine sandhills for A. sexlineata populations.     

The effects of fire, local environment and time on ant assemblages in fens and forests

We investigated the effects of the abiotic environment, plant community composition and disturbance by fire on ant assemblages in two distinct habitat types in the Siskiyou Mountains in northern California and southern Oregon, USA. Sampling over 2 years in burned and unburned Darlingtonia fens and their adjacent upland forests, we found that the effects of disturbance by fire depended on habitat type. In forests, fire intensity predicted richness in ant assemblages in both years after the fire, and plant community composition predicted richness 2 years after the fire. No factors were associated with richness in the species‐poor fen ant assemblages. Species‐specific responses to both habitat type and disturbance by fire were idiosyncratic. Assemblage composition depended on habitat type, but not disturbance by fire, and the composition of each assemblage between years was more dissimilar in burned than unburned sites.     

Seed depredation negates the benefits of midstory hardwood removal on longleaf pine seedling establishment

Midstory hardwoods are traditionally removed to restore longleaf pine on fire‐excluded savannas. However, recent evidence demonstrating midstory hardwood facilitation on longleaf pine seedling survival has brought this practice into question on xeric sites. Also, midstory hardwoods could facilitate longleaf pine seedling establishment, as hardwood litter may conceal seeds from seed predators or improve micro‐environmental conditions for seedling establishment. However, little is known about these potential mechanisms. In this study, we tracked longleaf pine seed depredation and germination in artificially seeded plots (11 seeds/m²) in a factorial design fully crossing hardwood retention or removal with vertebrate seed predator access or exclusion in the Sandhills Ecoregion of North Carolina, U.S.A. Seed depredation averaged 78% across treatments and was greatest in unexcluded plots. Hardwood retention did not affect seed depredation. Longleaf pine averaged 3.6 germinants/4 m² across treatments, and was six times more abundant where vertebrates had been excluded. Hardwood removal had a strong positive effect on seedling germination, likely due to the removal of litter, but only when vertebrates were excluded. Our results indicated midstory hardwoods are not facilitating longleaf pine seedling establishment. Nevertheless, our results indicated that hardwood removal may not increase longleaf pine seedling establishment, as seed depredation diminished the effectiveness of hardwood removal under mast seed availability. Collectively, these results demonstrate the underlying complexity of the longleaf pine ecosystem, and suggest that planting may need to be part of the restoration strategy on sites where seed depredation limits longleaf pine natural regeneration.     

Stochastic losses of fire‐dependent endemic herbs revealed by a 65‐year chronosequence of dispersal‐limited woody plant encroachment

The factors responsible for maintaining diverse groundcover plant communities of high conservation value in frequently burned wet pine savannas are poorly understood. While most management involves manipulating extrinsic factors important in maintaining species diversity (e.g., fire regimes), most ecological theory (e.g., niche theory and neutral theory) examines how traits exhibited by the species promote species coexistence. Furthermore, although many ecologists focus on processes that maintain local species diversity, conservation biologists have argued that other indices (e.g., phylogenetic diversity) are better for evaluating assemblages in terms of their conservation value. I used a null model that employed beta‐diversity calculations based on Raup–Crick distances to test for deterministic herbaceous species losses associated with a 65‐year chronosequence of woody species encroachment within each of three localities. I quantified conservation value of assemblages by measuring taxonomic distinctness, endemism, and floristic quality of plots with and without woody encroachment. Reductions in herb species richness per plot attributable to woody encroachment were largely stochastic, as indicated by a lack of change in the mean or variance in beta‐diversity caused by woody encroachment in the savannas studied here. Taxonomic distinctness, endemism, and floristic quality (when summed across all species) were all greater in areas that had not experienced woody encroachment. However, when corrected for local species richness, only average endemism and floristic quality of assemblages inclusive of herbs and woody plants were greater in areas that had not experienced woody encroachment, due to the more restricted ranges and habitat requirements of herbs. Results suggest that frequent fires maintain diverse assemblages of fire‐dependent herb species endemic to the region. The stochastic loss of plant species, irrespective of their taxonomic distinctness, to woody encroachment suggests that the relevance of niche partitioning or phylogenetic diversity to the management of biodiversity in wet pine savannas is minimal.     

Fire and regeneration: the role of seed banks in the dynamics of northern heathlands

Questions: How do species composition and abundance of soil seed bank and standing vegetation vary over the course of a post‐fire succession in northern heathlands? What is the role of seed banks – do they act as a refuge for early successional species or can they simply be seen as a spillover from the extant local vegetation? Location: Coastal Calluna heathlands, Western Norway. Methods: We analysed vegetation and seed bank along a 24‐year post‐fire chronosequence. Patterns in community composition, similarity and abundances were tested using multivariate analyses, Sørensen's index of similarity, vegetation cover (%) and seedling counts. Results: The total diversity of vegetation and seed bank were 60 and 54 vascular plant taxa, respectively, with 39 shared species, resulting in 68% similarity overall. Over 24 years, the heathland community progressed from open newly burned ground via species rich graminoid‐ and herb‐dominated vegetation to mature Calluna heath. Post‐fire succession was not reflected in the seed bank. The 10 most abundant species constituted 98% of the germinated seeds. The most abundant were Calluna vulgaris (49%; 12 018 seeds m^?2) and Erica tetralix (34%; 8 414 seeds m^?2). Calluna showed significantly higher germination the first 2 years following fire. Conclusions: Vegetation species richness, ranging from 23 to 46 species yr^?1, showed a unimodal pattern over the post‐fire succession. In contrast, the seed bank species richness, ranging from 21 to 31 species yr^?1, showed no trend. This suggests that the seed bank act as a refuge; providing a constant source of recruits for species that colonise newly burned areas. The traditional management regime has not depleted or destroyed the seed banks and continued management is needed to ensure sustainability of northern heathlands.     

The effects of fire on grassland bird communities of Barberspan,North West Province,South Africa

Considering the frequent nature of fires and resultant drastic change in habitat following fire, research on the effects of fire on birds in the grasslands of South Africa is surprisingly scarce. For at least five months after burns we followed the changes in bird species composition, species richness and densities of two controlled burns and one accidental fire at the Barberspan Nature Reserve in grasslands that had not been burned or grazed in 10 years. Compared with the control areas, species richness and densities increased in the burned areas immediately following the burns, with more species and birds recruited to the burned areas than were lost. Immediate post-burn opportunists tended to be larger species, and the biomass increase mirrored the increases in species richness and densities in burned areas. Avian species richness, densities and biomass tended to return to the initial conditions after a number of months. Although the bird communities from two controlled-burns differed before the burns, they converged to a characteristic immediate post-burn composition. Five months after the burns however, the bird communities reflected a pre-burn composition. Indications were that birds in an area larger than that burned were affected. Mosaic burning, with shifting large and small patches, should be considered on a landscape scale.