Fire frequency has a contrasting effect on vegetation and topsoil in subcoastal heathland,woodland and forest ecosystems,south-east Queensland,Australia

Ecosystems managed with contrasting fire regimes provide insight into the responses of vegetation and soil. Heathland, woodland and forest ecosystems along a gradient of resource availability were burnt over four decades in approximately 3- or 5-year intervals or were unburnt for 45–47 years (heathland, woodland), or experienced infrequent wildfires (forest: 14 years since the last fire). We hypothesized that, relative to unburnt or infrequent fires, frequent burning would favour herbaceous species over woody species and resprouting over obligate seeder species, and reduce understorey vegetation height, and topsoil carbon and nitrogen content. Our hypothesis was partially supported in that herbaceous plant density was higher in frequently burnt vegetation; however, woody plant density was also higher in frequently burnt areas relative to unburnt/infrequently burnt areas, across all ecosystems. In heathland, omission of frequent fire resulted in the dominance of fern Gleichenia dicarpa and subsequent competitive exclusion of understorey species and lower species diversity. As hypothesized, frequent burning in woodland and forest increased the density of facultative resprouters and significantly reduced soil organic carbon levels relative to unburnt sites. Our findings confirm that regular burning conserves understorey diversity and maintains an understorey of lower statured herbaceous plants, although demonstrates the potential trade-off of frequent burning with lower topsoil carbon levels in the woodland and forest. Some ecosystem specific responses to varied fire frequencies were observed, reflecting differences in species composition and fire response traits between ecosystems. Overall, unburnt vegetation resulted in the dominance of some species over others and the different vegetation types were able to withstand relatively high-frequency fire without the loss of biodiversity, mainly due to high environmental productivity and short juvenile periods.     

Effects of fire on vegetation and arthropods in a coastal heath,south‐east Queensland

Fire is an important part of many Australian ecosystems, and determining how it affects different vegetation communities and associated fauna is of particular interest to land managers. Here, we report on a study that used sites established during a 39‐year fire experiment in coastal heathland in southeastern Queensland to compare arthropod abundance and vegetation in 1.5–2.6 ha sites that were (i) long unburnt, (ii) burnt every 5 years and (iii) burnt every 3 years. We found that the abundance of ants was more than four times higher in the frequently burnt sites compared to long unburnt sits. Moreover, long unburnt sites had greater dominance of Xanthorrhoea johnsonii and Caustis recurvata, whereas burnt sites had greater cover of Lomandra filiformis, Leucopogon margarodes and Leucopogon leptospermoides. Our findings show that frequent fire can alter vegetation structure and composition, and this is matched by an increase in the relative dominance of ants in the arthropod community.     

Imprint of monsoonal patterns on the fish assemblage in coastal waters of south‐east India: a case study

The composition, species richness and diversity of a coastal fish assemblage from the Kalpakkam coast of south‐east India are described along with temporal distribution patterns related to seasonal fluctuations in dissolved oxygen, salinity, pH, chlorophyll‐a, phytoplankton and zooplankton species richness and density. A total of 244 fish species belonging to 21 orders, 87 families and 163 genera were recorded. The fish assemblage was dominated by reef‐associated species, followed by demersal species. The majority of the species (63%) are widely distributed in the western Indo‐Pacific as well as in the central Indo‐Pacific. Jaccard's coefficient analysis showed three distinct seasonal patterns of fish occurrence: pre‐monsoon (PrM), monsoon (M) and post‐monsoon (PoM). The maximum number of species was during the PrM period, followed by the PoM and M periods. Species occurrence analysis showed Sardinella longiceps to be dominant during PrM and M periods, Leiognathus dussumieri during the M period and Secutor insidiator and Secutor ruconius during the M and PoM periods. Canonical correspondence analysis indicated that salinity and rainfall were the two most influential environmental factors strongly correlated with temporal variation in the fish assemblage. The physico‐chemical conditions, in combination with factors such as greater food availability and shelter, might control the seasonal local distribution of the ichthyofauna in these Indian coastal waters.     

Early post‐fire regeneration in subalpine heathland and grassland in the Victorian Alpine National Park,south‐eastern Australia

Landscape fire (at the scale of square kilometres or more) is relatively rare in the alpine and subalpine environments of Australia. In early 1998, a major fire (the ‘Caledonia Fire’), burnt approximately 35 000 ha, of which approximately 3000 hectares was subalpine heathland, grassland and wetland within the Victorian Alpine National Park. This fire was one of only three landscape‐scale fires that have occurred anywhere in the treeless vegetation of the Victorian Alps in the past 100 years, the others being in 1939 and 1985. Monitoring of regeneration in subalpine vegetation commenced 3 weeks postfire. Sites were established in burnt grassland at Holmes Plain (1400 m a.s.l.) and burnt grassland and heathland at Wellington Plain (1480 m a.s.l.), and in unburnt grassland at both sites. In burnt grassland and heathland, the fire consumed much of the vegetation, leaving extensive areas of bare ground. The cover of dense vegetation declined from > 70% prefire, to approximately 15% immediately postfire. Bare ground at the Holmes and Wellington Plains sites ranged from 70% to 85% immediately postfire. By May 2000, approximately 2.5 years postfire, dense vegetation cover in grassland had increased to approximately 20%, and bare ground had decreased to an average of approximately 30%. In unburnt grassland, dense vegetation cover was generally > 95%, and the amount of bare ground less than 5%. The tussock‐forming snow grasses resprouted vigorously following fire, and had flowered prolifically after 1 year. In heathland, most of the shrubs were incinerated, leaving close to 100% bare soil. Since then, a number of grasses and some dominant shrubs have resprouted vigorously, with some seedling regeneration. By May 2000, in heathland, bare soil was still > 50% and dense vegetation < 20%. Such ground cover conditions during this early postfire period were well below prefire levels, and well below the levels necessary to protect alpine soils from erosion. The Caledonia Fire has provided a rare opportunity to study ecological processes associated with postfire regeneration in treeless subalpine landscapes.     

Effects of fire regime on plant species richness and composition differ among forest,woodland and heath vegetation

Question

Do the effects of fire regimes on plant species richness and composition differ among floristically similar vegetation types?

Location

Booderee National Park, south‐eastern Australia.

Methods

We completed floristic surveys of 87 sites in Sydney Coastal dry sclerophyll vegetation, where fire history records have been maintained for over 55 years. We tested for associations between different aspects of the recent fire history and plant species richness and composition, and whether these relationships were consistent among structurally defined forest, woodland and heath vegetation types.

Results

The relationship between fire regime variables and plant species richness and composition differed among vegetation types, despite the three vegetation types having similar species pools. Fire frequency was positively related to species richness in woodland, negatively related to species richness in heath, and unrelated to species richness in forest. These different relationships were explained by differences in the associations between fire history and species traits among vegetation types. The negative relationship between fire frequency and species richness in heath vegetation was underpinned by reduced occurrence of resprouting species at high fire frequency sites (more than four fires in 55 years). However, in forest and woodland vegetation, resprouting species were not negatively associated with fire frequency.

Conclusions

We hypothesize that differing relationships among vegetation types were underpinned by differences in fire behaviour, and/or biotic and abiotic conditions, leading to differences in plant species mortality and post‐fire recovery among vegetation types. Our findings suggest that even when there is a high proportion of shared species between vegetation types, fires can have very different effects on vegetation communities, depending on the structural vegetation type. Both research and management of fire regimes may therefore benefit from considering vegetation types as separate management units.     

Cultural legacies,fire ecology,and environmental change in the Stone Country of Arnhem Land and Kakadu National Park,Australia

We use the fire ecology and biogeographical patterns of Callitris intratropica, a fire‐sensitive conifer, and the Asian water buffalo (Bubalus bubalis), an introduced mega‐herbivore, to examine the hypothesis that the continuation of Aboriginal burning and cultural integration of buffalo contribute to greater savanna heterogeneity and diversity in central Arnhem Land (CAL) than Kakadu National Park (KNP). The ‘Stone Country’ of the Arnhem Plateau, extending from KNP to CAL, is a globally renowned social–ecological system, managed for millennia by Bininj‐Kunwok Aboriginal clans. Regional species declines have been attributed to the cessation of patchy burning by Aborigines. Whereas the KNP Stone Country is a modern wilderness, managed through prescribed burning and buffalo eradication, CAL remains a stronghold for Aboriginal management where buffalo have been culturally integrated. We surveyed the plant community and the presence of buffalo tracks among intact and fire‐damaged C. intratropica groves and the savanna matrix in KNP and CAL. Aerial surveys of C. intratropica grove condition were used to examine the composition of savanna vegetation across the Stone Country. The plant community in intact C. intratropica groves had higher stem counts of shrubs and small trees and higher proportions of fire‐sensitive plant species than degraded groves and the savanna matrix. A higher proportion of intact C. intratropica groves in CAL therefore indicated greater gamma diversity and habitat heterogeneity than the KNP Stone Country. Interactions among buffalo, fire, and C. intratropica suggested that buffalo also contributed to these patterns. Our results suggest linkages between ecological and cultural integrity at broad spatial scales across a complex landscape. Buffalo may provide a tool for mitigating destructive fires; however, their interactions require further study. Sustainability in the Stone Country depends upon adaptive management that rehabilitates the coupling of indigenous culture, disturbance, and natural resources.     

Pollen,wind and fire: how to investigate genetic effects of disturbance‐induced change in forest trees

Understanding the consequences of habitat disturbance on mating patterns although pollen and seed dispersal in forest trees has been a long‐standing theme of forest and conservation genetics. Forest ecosystems face global environmental pressures from timber exploitation to genetic pollution and climate change, and it is therefore essential to comprehend how disturbances may alter the dispersal of genes and their establishment in tree populations in order to formulate relevant recommendations for sustainable resource management practices and realistic predictions of potential adaptation to climate change by means of range shift or expansion (Kremer et al. 2012 ). However, obtaining reliable evidence of disturbance‐induced effects on gene dispersal processes from empirical evaluation of forest tree populations is difficult. Indeed, tree species share characteristics such as high longevity, long generation time and large reproductive population size, which may impede the experimenter's ability to assess parameters at the spatial and time scales at which any change may occur (Petit and Hampe 2006 ). It has been suggested that appropriate study designs should encompass comparison of populations before and after disturbance as well as account for demonstrated variation in conspecific density, that is, the spatial distribution of mates, and forest density, including all species and relating to alteration in landscape openness (Bacles & Jump 2011 ). However, more often than not, empirical studies aiming to assess the consequences of habitat disturbance on genetic processes in tree populations assume rather than quantify a change in tree densities in forests under disturbance and generally fail to account for population history, which may lead to inappropriate interpretation of a causal relationship between population genetic structure and habitat disturbance due to effects of unmonitored confounding variables (Gauzere et al. 2013). In this issue, Shohami and Nathan ( 2014 ) take advantage of the distinctive features of the fire‐adapted wind‐pollinated Aleppo pine Pinus halepensis (Fig. 1) to provide an elegant example of best practice. Thanks to long‐term monitoring of the study site, a natural stand in Israel, Shohami and Nathan witnessed the direct impact of habitat disturbance, here taking the shape of fire, on conspecific and forest densities and compared pre‐ and postdisturbance mating patterns estimated from cones of different ages sampled on the same surviving maternal individuals (Fig. 2). This excellent study design is all the more strong that Shohami and Nathan took further analytical steps to account for confounding variables, such as historical population genetic structure and possible interannual variation in wind conditions, thus giving high credibility to their findings of unequivocal fire‐induced alteration of mating patterns in P. halepensis. Most notably, the authors found, at the pollen pool level, a disruption of local genetic structure which, furthermore, they were able to attribute explicitly to enhanced pollen‐mediated gene immigration into the low‐density fire‐disturbed stand. This cleverly designed research provides a model approach to be followed if we are to advance our understanding of disturbance‐induced dispersal and genetic change in forest trees.     

深圳南山区天然森林群落多样性及演替现状

对南山区5个主要天然森林群落(铁榄群落、鼠刺 降真香群落、鸭脚木群落、假苹婆群落、水翁 假苹婆群落)的组成结构及物种多样性进行分析,并与相邻的香港地区地带性森林群落(黄桐群落)作比较。结果表明,依照亚热带及南亚热带森林群落演替规律,南山区天然林处于不同的演替发育阶段：铁榄群落处于演替第3阶段;鼠刺 降真香群落处于第4阶段;其它3个群落处于第5阶段,均未达到稳定的顶极群落阶段。随着铁榄群落、鼠刺 降真香群落、鸭脚木群落、假苹婆群落、水翁 假苹婆群落这个演替序列,物种丰富度的变化规律是：先逐渐上升,到达一个峰值,再缓慢下降。Shannon-Wiener指数和Pielous均匀度指数的变化规律与物种丰富度相同,Simpson指数变化曲线与这些指数相反。但这些指数反映的结果是一致的。综合多个指数分析,鸭脚木群落物种多样性最大,即当群落中阳生性树种与中生性树种优势度相差不大时。群落具有最大的物种多样性。多样性比较结果显示,南山森林群落物种多样性大大低于香港黄桐群落。5个群落的Shannon—Wiener指数在2．04～2．953之间,明显低于黄桐群落,其Shannon—Wiener指数为4．74;Simpson指数0．1～0．268,黄桐群落为0．05;Pielous均匀度指数64．2％～74％,黄桐群落为79％。南山森林群落物种多样性水平低下的状况与长期的人类干扰有关,必须尽快采取“封山育林”等相应措施来促进群落的保护和恢复。     

Ecosystem recovery in terra firme forests after cutting and burning: a comparison on species richness, floristic composition and forest structure in the Jaú National Park, Amazonia

Six hectares, three in a primary forest and three in a 40 year old secondary forest were inventoried for all trees with Diameter at Breast Height (DNH) of 10 cm or greater in a terra firme forest 200 km north-east of Manaus, central Amazonia in order to compare the difference between structure, species richness and floristic composition. Both species richness and tree density were significantly higher in the upland forest than in the secondary forest. The forest structure pattern analysed (DBH, basal area and estimated dry biomass) did not differ significantly between the two forest types. Similarity indices at species level were only 14%. In the 3 ha of primary forest the number of species varied from 137 to 159, the number of individuals from 639 to 713, total basal area from 32.8 to 40.2 m² and estimate total of above-ground dry biomass (AGBM) from 405 to 560 tons per ha. In the 3 ha of secondary forest, the number of species varied from 86 to 90, the number of individuals from 611 to 653, total basal area from 28.8 to 39.9 m² and estimated total AGBM from 340 to 586 tons per ha. Family Importance Value (FIV) is the sum of relative density, dominance and richness of a family. The most important families in relation to FIV were Burseraceae, Chrysobalanaceae, Lecythidaceae, Myristicaceae, Bombacaceae, Fabaceae and Mimosaceae in the 3 ha of primary forest, while Burseraceae, Lecythidaceae, Sapotaceae, Arecaceae and Cecropiaceae were the most important families in the 3 ha of secondary forest. Importance Value Index (IVI) is the sum of relative density, dominance and frequency of a species. Alexa grandiflora (Caesalpiniaceae), Sckronema micranthum (Bombacaceae) and Pourouma guianensis (Cecropiaceae) were the most important species in relation IVI, in the primary forest, while Eschweilera grandiflora (Lecythidaceae), Protium apiculatum (Burseraceae) and Bertholletia excelsa (Lecythidaceae) were the most important species in the secondary forest. We conclude that species richness was significandy different between the two forests, but that forest structure patterns analysed in this study (DBH, basal area and dry biomass) were similar. This demonstrates that 40 years was sufficient time for the secondary forest to recover the original structure of the primary forest, but not the original species richness. The low species similarity between the two forests indicates that the floristic composition was quite distinct and that the mixture of primary forest and disturbed forest has led to an increase in total species diversity.     

Local‐ and landscape‐level effects of land use change on bird diversity in Abiata‐Shalla Lakes National Park,Ethiopia

Understanding the effects of anthropogenic disturbances on biodiversity is important for conservation prioritization. This study examined the effects of vegetation degradation on bird diversity in Abiata‐Shalla Lakes National Park, Ethiopia. We surveyed birds and vegetation structure between January and March 2015 in disturbed (impacted by settlement and agriculture) and undisturbed (not impacted) transects of two vegetation types (savannah woodland and gallery forest). We compared between disturbed and undisturbed transects at local (within vegetation types) and landscape (across vegetation types) levels: (a) avian species richness of the entire assemblage and feeding guilds and (b) species assemblage composition. We found significantly greater mean and total bird species richness of the entire assemblage and insectivore and granivore feeding guilds in the undisturbed transects, while the nectarivore guild was totally absent in the disturbed transects. We also found significant differences in bird species assemblage composition between the disturbed and undisturbed transects both within and across the vegetation types, and bird species assemblage composition at the landscape level was positively correlated with tree abundance and understorey vegetation height. In conclusion, our results demonstrate and add to the increasing body of evidence concerning the adverse effects of human‐induced vegetation change on bird diversity.     

Long-term effects of fire frequency and season on herbaceous vegetation in savannas of the Kruger National Park,South Africa

Aim s: The long-term effects of changing fire regimes on the herbaceous component of savannas are poorly understood but essential for understanding savanna dynamics. We present results from one of the longest running (>44 years) fire experiments in savannas, the experimental burn plots (EBPs), which is located in the Kruger National Park (South Africa) and encompasses four major savanna vegetation types that span broad spatial gradients of rainfall (450–700 mm) and soil fertility.Methods: Herbaceous vegetation was sampled twice in the EBPs using a modified step-point method, once prior to initiation of the experiment (1954) and again after 44–47 years. Different combinations of three fire frequency (1-, 2- and 3-year return intervals) and five season (before the first spring rains, after the first spring rains, mid-summer, late summer and autumn) treatments, as well as a fire exclusion treatment, were applied at the plot level (~7 ha each), with each treatment (n = 12 total) replicated four times at each of the four sites (n = 192 plots total). The effects of long-term alterations to the fire regime on grass community structure and composition were analyzed separately for each site.Important Findings: Over the 44+ years duration of the experiment, fires were consistently more intense on sites with higher mean annual rainfall (>570 mm), whereas fires were not as intense or consistent for sites with lower and more variable rainfall (<510 mm) and potentially higher herbivory due to greater soil fertility. Because the plots were open to grazing, the impacts of herbivory along with more variable rainfall regimes likely minimized the effects of fire for the more arid sites. As a consequence, fire effects on grass community structure and composition were most marked for the higher rainfall sites and generally not significant for the more arid sites. For the high-rainfall sites, frequent dry season fires (1- to 3-year return intervals) resulted in high grass richness, evenness and diversity, whereas fire exclusion and growing season fires had the lowest of these measures and diverged the most in composition as the result of increased abundance of a few key grasses. Overall, the long-term cumulative impacts of altered fire regimes varied across broad climatic and fertility gradients, with fire effects on the grass community decreasing in importance and herbivory and climatic variability likely having a greater influence on community structure and composition with increasing aridity and soil fertility.     

三峡水库175 m试验性蓄水期库区及其上游江段鱼类群落结构时空分布格局

根据2010—2012年在三峡水库及其上游江段5个江段的商业性渔获物调查结果,对该区域鱼类群落结构的时空分布格局进行了分析。调查中共收集到鱼类87种,隶属于8目18科63属。沿坝前江段溯河而上至库尾以上流水江段,鱼类种类数逐渐增加。采用聚类分析(CA)和非度量多维标度(NMDS)方法对三峡水库175 m试验性蓄水期间各江段的鱼类种类组成进行分析,发现这5个调查江段的鱼类种类组成可以分为两个类群:类群Ⅰ包括秭归、巫山、云阳3个库区的江段,其鱼类种类组成在各年间的差异程度较大;而类群Ⅱ包括库尾的涪陵江段以及上游的江津江段,其鱼类种类组成在各年间差异程度较小。采用CA和NMDS方法对鱼类群落结构时空分布格局的分析结果表明,5个调查江段的鱼类群落结构在各年间可以分为不同类群;云阳与涪陵江段的鱼类群落结构的相似性逐年增加,而与秭归、巫山江段的相似性逐年减少;涪陵江段与江津江段的鱼类群落结构相似性也呈逐年减少趋势。总体而言,175m试验性蓄水对库中和库尾江段的鱼类群落结构的影响较大,但对库首以及库尾以上流水江段的影响均较小。     

Response surfaces for the combined effects of heat shock and smoke on germination of 16 species forming soil seed banks in south‐east Australia

Abstract There is limited understanding of how fire‐related cues such as heat shock and smoke can combine to affect the germination response of seeds from fire‐prone vegetation because combinations of multiple levels of both cues have rarely been investigated. Germination response surfaces were determined for the combination of heat shock and smoke by applying factorial combinations of temperature (up to 100°C) and aerosol smoke (0–20 min) to 16 species that form soil seed banks in the Sydney region of south‐eastern Australia. Duplicate populations of three species were also examined to assess the constancy of a species response surface. Of the 19 populations examined, 16 showed a germination response to both the fire cues, which combined interactively in 14 populations, and independently in two. No population responded only to a single cue; however, seeds of 11 populations responded to heat in the absence of smoke, and nine responded to smoke in the absence of heat. Heat applied in the absence of smoke negatively affected germination in seven populations, either progressively as temperature increased, or above a set temperature. Negative germination responses over part of the temperature range were fully reversed at higher temperatures for unsmoked seeds of four populations (curvilinear heat response). Smoke effects were most frequently positive over all or part of the range of durations used, and when combined with heat frequently fully or partially reversed negative heat effects. Three populations required the obligatory combination of smoke and heat. A novel response to the cues was observed for three species, with smoke reversing negative heat effects at 75°C, being supplanted by a positive heat response of unsmoked seed at 100°C. The response surface for duplicate populations of two of the three species examined was variable. Heat shock and smoke frequently combined to affect germination, in both positive and negative ways. Consequently, to gain an accurate assessment of the response of seeds to fires, an experimental design that samples within the potential response zones of germination cues is essential.     

Responses of forest eucalypts to moderate and high intensity fire in the Tingle Mosaic,south‐western Australia: comparisons between locally endemic and regionally distributed species

Responses of three locally endemic (Eucalyptus brevistylis, Eucalyptus jacksonii and Eucalyptus guilfoylei) and three co‐occurring regional eucalypts (Eucalyptus marginata, Eucalyptus diversicolor and Corymbia calophylla) to moderate‐ and high‐intensity fires were examined in granitic terrain of the Tingle Mosaic, south‐western Australia. Significant associations between diameter distributions and community type (CT) for each species (P < 0.001) suggest that fire response will also vary according to the habitat/fire interaction. None of the species were fire sensitive, although responses differed both within and between species, and with CT. All species examined predominately consisted of several cohorts of regeneration within a forest stand. Each species had thick bark and re‐sprouted from crown epicormics following 100% scorch of the mature tree. The quantity and type of regeneration in relation to gaps created by individual dead trees following fire differed between species; for example, E. guilfoylei regeneration was strongly associated with gaps, and C. calophylla with non‐gaps. However, regeneration of the two tall open‐forest species, E. jacksonii and E. diversicolor were not most associated with either gaps or non‐gaps. The very low levels of regeneration of E. brevistylis following fire and the high proportion of stems of E. jacksonii that were hollow butted (40% of stems > 1 m DBHOB) may be factors associated with narrow endemism of these species and may affect the vulnerability of these eucalypts to fire. The interaction of seed availability, intense fires and subsequent rainfall may be critical in the long term survival of these species. Eucalyptus guilfoylei, by contrast, appears well adapted to the increasing levels of disturbance likely in the region where these species occur. The vulnerability of a locally endemic species in a fire‐prone environment is likely to reflect differences to the prevailing adaptations of the dominant species rather than an inherent ability of the species to survive or respond. Management regimes must account for variations in species responses to fire in different CTs if the long‐term survival chances of local endemics are to be enhanced.     

Effects of smoke,heat and charred wood on the germination of dormant soil‐stored seeds from a Eucalyptus baxteri heathy‐woodland in Victoria,SE Australia

The effects of dry heat, wet heat, charred wood and smoke on the germination of dormant soil‐stored seeds from a Eucalyptus woodland in western Victoria were tested by using a glasshouse seed‐bank germination experiment. Seedling density, species richness and species composition were compared between replicated treated and control samples. A total of 5922 seedlings, comprising 59 plant species, was recorded from the soil samples over a period of 150 days. While a few species dominated (including Centrolepis strigosa, Wahlenbergia gracilenta and Ixodia achillaeoides), 26 species were represented by fewer than five seedlings and 18 species were restricted to single treatment types. With the exception of charred wood, all treatments led to a significant increase in seed germination relative to the control. The highest number of germinants was obtained for the smoke treatment, with a mean (± SE) of 12 547 ± 449 seedlings m^–2. Heat treatments yielded intermediate densities, with means (± SE) varying between 7445 ± 234 and 9133 ± 445 seedlings m^–2. In comparison with the estimates of seed‐bank sizes from other fire‐prone ecosystems, these densities are high. Species richness differed significantly among treatments. Highest mean richness was recorded in the smoke treatment and lowest for the control and charred wood treatments. There were significant differences in seed‐bank species composition between treatment types based on analysis of similarity (Anosim) using Bray–Curtis similarity. While heat was a specific requirement for triggering germination in hard‐seeded species (e.g. Fabaceae), smoke was the most effective trigger for species from a broad range of other families. The potentially confounding effect of physical and chemical mechanisms of germination stimulation in heated bulk soil samples is raised as an issue requiring further investigation in relation to the role of smoke as a germination trigger.     

Potential effects of prescribed savannah burning on the diet selection of forest buffalo (Syncerus caffer nanus) in Lopé National Park,Gabon

Seasonality and management are factors that may affect the diet selection of the forest buffalo (Syncerus caffer nanus). Fire is considered a major driving force in savannah systems and prescribed burning is a commonly applied conservation tool in protected areas such as Lopé National Park, Gabon. Prescribed annual fires contribute to the maintenance of open areas and provide high‐quality forage for forest buffalo, a major herbivore in the park. We used microhistological faecal analysis to determine the diet selection of forest buffalo and measured the extent of variation between a dry season, preburn and a wet season, postburn sampling period. The buffalo diet comprised mainly of monocotyledons, primarily grasses (Poaceae) and sedges (Cyperaceae). Intake of open‐area‐associated plant species was higher in the wet season, postburn treatment sampling period (97%) than the dry season, preburn sampling period (87%), which corresponded conversely to a reduction in forest‐associated Marantaceae plants (10% versus 1%). High proportions of grasses and sedges in the diet signify the importance of open areas for forest buffalo. Controlled burning as tool for maintenance of open areas may play a key role in the meta‐population management of the forest buffalo.