Changes in arbuscular mycorrhizal fungal communities along a river delta island in northeastern Brazil

Arbuscular mycorrhizal fungi (AMF) play a key role in the maintenance of the balance of terrestrial ecosystems, but little is known about the biogeography of these fungi, especially on tropical islands. This study aims to compare AMF community structure along a transect crossing a fluvial-marine island and relate these communities with soil and vegetation parameters to shed light on the forces driving AMF community structure on a local scale. We tested the hypothesis that the composition of AMF communities changes across the island, even within short distances among sites, in response to differences in edaphic characteristics and vegetation physiognomies. We sampled roots and soils in five different natural and degraded habitats: preserved mangrove forest (MF), degraded mangrove forest (MD), natural Restinga forest (RF), and two regeneration Restinga forests (RR1 and RR2) on Ilha da Restinga, northeastern Brazil. We determined the mycorrhizal colonization rate and AMF community structure based on morphological spore identification. The island soils were sandy with pH varying from acid to neutral; higher levels of organic matter were registered in RF and lower in MF; other chemical and physical soil attributes differed along the habitat types on the island. In total, 22 AMF species were identified, without any difference in species richness. However, the diversity and composition of AMF communities, spore abundance per families, and mycorrhizal colonization were statistically different among the habitats. The composition of AMF communities was strongly related to soil characteristics, especially the sum of exchangeable bases. Our results indicate that the different habitat types have diverse AMF communities even within short distances among habitats. In conclusion, islands with high spatial heterogeneity in soil parameters and diverse vegetation are potential refuges for the diversity conservation of AM fungi.     

Colonisation of experimentally immersed wood in south eastern Australia: responses of feeding groups to changes in riparian vegetation

We investigated macroinvertebrate abundance and functional feeding groups colonising experimentally-positioned woody substrates of different species in streams with three different riparian vegetation types. Native Eucalyptus forest formed a dense closed canopy over our streams; introduced (exotic, alien) pine plantation forest did not fully shade the streams, and grassland streams were completely open, although with woody riparian vegetation well upstream of our sites. Macroinvertebrate assemblages varied taxonomically and functionally with both wood species and riparian vegetation composition. Two specialist feeding groups responded clearly to riparian vegetation: wood gougers were most common in forested streams, and algal grazers in more open streams. Gougers colonised native Eucalyptus wood in preference to alien species. Other feeding groups responses showed complex interactions between vegetation and wood type. Our results indicate the importance of sampling appropriate substrates when assessing questions of this type – if seeking shifts in functional organisation, the substrates on which the feeding groups of interest occur must be sampled. The composition of the riparian strip may influence xylophilous communities as much as the structure (i.e. whether closed or open).     

High diversity of arbuscular mycorrhizal fungi in natural and anthropized sites of a Brazilian tropical dry forest (Caatinga)

Arbuscular mycorrhizal fungi (AMF) establish symbiotic associations with higher plants, which support the establishment and maintenance of plant communities across a range of environments, including those adversely affected by anthropogenic activity as well as natural sites. This study aimed at determining the diversity and distribution of AMF in areas of the tropical semi-arid region of Caatinga, Brazil, and compare areas in a naturally preserved state with anthropized sites. We characterized AMF communities in soil samples (n = 108), based on morphological taxonomy, at three sampling occasions and from six areas (typical Caatinga, extremely sandy Caatinga, stony Caatinga, rocky Caatinga, and two typical Caatinga areas that had been modified by human activities), at the National Park of Catimbau, Northeast Brazil. Eighty AMF species were recorded, with Glomus and Acaulospora predominating at all sites. There were significant differences in the composition of AMF communities between natural and anthropized sites, and among sampling occasions. Habitat-types also influenced AMF communities in Caatinga. Extensive tropical dry forest areas, such as the Catimbau National Park possess distinct niches, which maintain diverse AMF communities that are determined by anthropogenic activities, as well as vegetation types and environmental conditions.     

Communities of Arbuscular Mycorrhizal Fungi Detected in Forest Soil Are Spatially Heterogeneous but Do Not Vary throughout the Growing Season

Despite the important ecosystem role played by arbuscular mycorrhizal fungi (AMF), little is known about spatial and temporal variation in soil AMF communities. We used pyrosequencing to characterise AMF communities in soil samples (n = 44) from a natural forest ecosystem. Fungal taxa were identified by BLAST matching of reads against the MaarjAM database of AMF SSU rRNA gene diversity. Sub-sampling within our dataset and experimental shortening of a set of long reads indicated that our approaches to taxonomic identification and diversity analysis were robust to variations in pyrosequencing read length and numbers of reads per sample. Different forest plots (each 10×10 m and separated from one another by 30 m) contained significantly different soil AMF communities, and the pairwise similarity of communities decreased with distance up to 50 m. However, there were no significant changes in community composition between different time points in the growing season (May-September). Spatial structure in soil AMF communities may be related to the heterogeneous vegetation of the natural forest study system, while the temporal stability of communities suggests that AMF in soil represent a fairly constant local species pool from which mycorrhizae form and disband during the season.     

Host identity and functional traits determine the community composition of the arbuscular mycorrhizal fungi in facultative epiphytic plant species

The epiphytic vascular mycobiota is scarce and facultative in semi-arid Mediterranean ecosystems. However, unlike in soil conditions, little is known about the factors driving mycorrhizal communities in epiphytic environments. Here, we investigated the arbuscular mycorrhizal fungi (AMF) harboured by 31 plant species occurring on the trunks of Phoenix dactylifera. We wanted to ascertain if host identity and plant functional traits shape mycorrhizal communities. Specifically, we tested the plant life-cycle (perennial versus annual), the plant life-form (herbaceous versus woody), the plant origin (exotic versus native) and the plant species. The plant affiliation to species strongly influenced the AMF community composition. Plant life-form and plant life-cycle also shaped indicator taxa. The AMF structure differed between annual and perennial species and higher AMF richness was detected in perennial plants. The epiphytic plants associated with AMF irrespective of whether they were native or not, probably because here no functional differences derive from plant origin.     

桉树种植对林地土壤丛枝菌根真菌群落结构及多样性的影响

桉树(Eucalyptus spp.)种植所产生的生态争议已受到广泛关注。丛枝菌根真菌(Arbuscular Mycorrhizal Fungi, AM真菌)是土壤微生物的重要组成部分,与根系共生后可促进植物的养分运输、提高植物逆境生存能力等。然而,桉树种植对土壤AM真菌群落结构和功能的影响尚不清楚。研究比较了次生林改种桉树后不同年限(2年/5年/10年)的土壤理化性质、AM真菌种类、群落组成及多样性的变化。结果表明,桉树种植显著改变了土壤理化性质,具体表现为2年生和10年生桉树林中土壤pH和有机碳显著降低(P0.05);AM真菌的孢子密度在桉树林土壤中显著低于次生林土壤(其中在5年生土壤中最低);AM真菌的种丰度随种植年份的增加逐渐下降,在10年生桉树林土壤中有所恢复; 5年生桉树的菌根侵染率最高,10年生桉树侵染率最低。AM真菌群落组成和结构发生显著变化,优势种Funneliforms geosporus的丰度在2年生和10年生林地中显著降低;而Septoglomus deserticola的丰度在2年生和10年生林地中显著增加。另外,冗余分析(Redundancy analysis, RDA)结果表明,土壤AM真菌群落结构主要受土壤pH值(解释率:89.88%)变化的影响。研究揭示了次生林改种桉树林后土壤AM真菌的群落变化特征,为桉树林的栽培管理和环境修复提供了数据支撑。     

Differences in Arbuscular Mycorrhizal Fungal Community Composition in Soils of Three Land Use Types in Subtropical Hilly Area of Southern China

Land use type is key factor in restoring the degraded soils due to its impact on soil chemical properties and microbial community. In this study, the influences of land use type on arbuscular mycorrhizal fungal (AMF) community and soil chemical properties were assessed in a long-run experimental station in subtropical hilly area of southern China. Soil samples were collected from forest land, orchard and vegetable field. Soil chemical properties were analyzed, and PCR-DGGE was performed to explore the AMF community structure. Cloning and sequencing of DGGE bands were conducted to monitor AMF community composition. Results indicate that the contents of total P, available P and available K were the highest while the contents of soil organic matter, total N, total K and available N were the lowest in vegetable field soils, with forest land soils vice versa. According to DGGE profiling, AMF community in forest soils was more closely related to that in orchard soils than that in vegetable field soils. Sequencing indicated that 45 out of 53 excised bands were AMF and 64.4% of AMF belonged to Glomeraceae, including some “generalists” present in all soils and some “specialists” present only in soils of particular land use. Category principle component analysis demonstrated that total N, soil organic matter and available P were the most important factors affecting AMF community, and some AMF phylotypes were closely associated with particular soil chemical properties. Our data suggest that AMF communities are different with different land use types.     

海南西部桉树人工林土壤水分变化特征及其对林龄的响应

在海南西部儋州林场选取空间相邻、自然环境相似、不同林龄与连栽代次的桉树林样地和椰树林对照样地,通过2010—2012年连续3a定点取样,研究桉树林土壤水分变化特征及其对林龄的响应,分析桉树林种植对林地土壤水分的影响。结果表明:(1)1—4月土壤含水量持续减少,5—6月波动较大,7—10月增加到年内极大值,11—12月降低,但处于年内较高水平。(2)短伐桉树林(二代5年桉树林、三代1年桉树林、三代4年桉树林)、20a桉树林以及10a椰树林5个样地的月均土壤含水量存在显著或极显著差异。二代5年桉树林与三代1年桉树林之间以及20a桉树林与10a椰树林之间的土壤含水量差异均不显著;其余各林地之间土壤含水量差异显著或极显著。(3)随着土壤深度增加,短伐桉树林与20a桉树林、10a椰树林之间的土壤含水量差异增大。表层0—30 cm短伐桉树林年均土壤含水量为6.08%,20a桉树林为7.53%,10a椰树林为6.93%;80 cm以下则分别为8.10%、11.72%和11.95%。与10a椰树林、20a桉树林相比,短伐桉树林对土壤深层水分有较大负面影响。(4)短伐桉树林、20a桉树林和10a椰树林土壤含水量的变异系数由表层到深层逐渐递减,其中林龄较大的短伐桉树林变异系数较大,且变异系数较大的土层也较深厚。与20a桉树林、10a椰树林相比,林龄较大的短伐桉树林对深层土壤水分的消耗较多。(5)连栽代次愈多,林龄越大,土壤含水量愈少;采伐之后1a桉树林的土壤含水量明显增加,有利于桉树后期生长。     

Landscape mosaic of Araucaria forest and forest monocultures influencing understorey spider assemblages in southern Brazil

Abstract This study investigates how abundance, diversity and composition of understorey spiders were influenced by four different forest habitats in a southern Brazilian Araucaria forest. The study area encompasses a landscape mosaic comprised of Araucaria forest, Araucaria plantation, Pinus plantation, and Eucalyptus plantation. Understorey spiders were collected by beating the vegetation inside three patches of each forest habitat. To assess possible predictors of spider assemblage structure, several patch features were analysed: potential prey abundances, estimation of vegetation cover, diversity index of vegetation types, patch ages, patch areas, and geographical distance between patches. To assess the influence of high‐level taxa approaches on spider assemblage patterns, analyses were carried out individually for family, genera and species levels. Additionally, Mantel tests were carried out in underlying similarity matrices between each taxon. Significant differences in spider abundances among forest habitats were found. Pinus plantations showed the highest abundance of spiders and Eucalyptus plantations showed the lowest abundance. Spider abundance was significantly influenced by patch ages, geographical distance and vegetation cover. Expected numbers of families, genera and species did not vary among forest habitats. Spider composition of two Eucalyptus patches differed from the other forest patches, probably due to their low vegetation cover and isolation. Genera composition was the best correlate of species composition, showing that a higher‐level surrogate can be an alternative to the species approach. The understorey spider diversity in this managed area could be maintained when suitable habitat structures are provided, thus ensuring the connectivity between different habitat types. Further studies should focus on individual species responses to the conversion of native forest to monocultures.     

Nutrient relocation,hydrological functions,and soil chemistry in plantations as compared to natural forests in central Yunnan,China

The relocation of nutrients among dominant plant species, along with hydrological functions and soil chemistry in five plant communities, including Eucalyptus plantation, Pinus plantation, shrubland, semi-natural, and natural secondary forests were investigated in central Yunnan, China. The nutrient P, N, and K accumulation in above-ground biomass of Eucalyptus smithii (stems, barks, branches, and leaves) were the highest, followed by Pinus yunnanensis of both the Pinus plantation and the semi-natural forest. The nutrient retranslocation efficiency (NRE) of E. smithii was the highest for nutrient P, N, and K with values of 56, 66, and 67%, respectively, among the dominant plant species of the five plant communities, while the NRE of P. yunnanensis in Pinus plantation had the second highest value of NRE for nutrient N. The nutrient content (available P, N, and soil organic matter) in the upper two soil layers under Eucalyptus and Pinus plantations was correspondingly found to be lower than that of the other forests. Moreover, under the Eucalyptus and Pinus plantations, surface runoff, soil erosion, and nutrient loss were more serious, and the water storage of litterfall and canopy interception were significantly lower than that in the other plant communities. Accordingly, we suggest that single-species plantations cannot present the same ecological benefits as natural forests, because of their simple, uniform structures, and the characteristics of the dominant plant species.     

Plant and soil seed bank diversity across a range of ages of Eucalyptus grandis plantations afforested on arable lands

Aims

Plantation forests are often assumed to have reduced biodiversity relative to unmanaged forests. However, existing knowledge is based on studies of rotation-aged tree crops. We investigated how Eucalyptus afforestation of agricultural land affected plant species composition and biodiversity across a range of plantation ages (1–10 years). We also studied whether the soil seed bank could contribute to regeneration of existing vegetation in such plantations.

Methods

We used a chronosequence approach to evaluate plant and seed species composition and diversity in forests and soil seed banks. We also quantified the similarity of seed banks and aboveground vegetation within plantation sites of a given age. Plantation sites were also compared to a nearby, mature pine forest.

Results

Total plant species number, density and diversity in Eucalyptus grandis plantations increased for the first 3 years plantation establishment, then stabilized or decreased for the next 1–2 years and then increase significantly over the following years. Species number and density in soil seed bank increased significantly with plantation age only after an initial 6-year decrease. Shannon–Wiener index of total species diversity did not significantly differ with plantation age. The understory vegetation and soil seed bank were dominated by pioneer species in the first 3 years, but intermediate-successional and shade-tolerant species gradually invaded as plantations developed further. After 7 years, E. grandis plantation understories were composed of mainly shade-tolerant species. Nevertheless, the diversity of the diversity of intermediate-successional in soil seed banks were higher than that of shade-tolerant species in soil seed banks at this age range (7–10 year). Among species successfully germinated from soil seed banks, 48 % were not found in the aboveground plant community. Similarities between the species in the soil seed bank and the aboveground vegetation were low for both plantation and control forests and did not significantly change with plantation ages.

Conclusions

E. grandis likely produces a changing microclimate during plantation development, which in turn drives composition and diversity dynamics in understory vegetation and soil seed banks after the afforestation of agricultural land. The first 4 years after plantation establishment is associated with lower plant and soil seed bank diversity, meriting a greater focus on biodiversity stabilization and possibly longer rotation periods.     

Arbuscular mycorrhizal fungal communities along a pedo-hydrological gradient in a Central Amazonian terra firme forest

Little attention has been paid to plant mutualistic interactions in the Amazon rainforest, and the general pattern of occurrence and diversity of arbuscular mycorrhizal fungi (AMF) in these ecosystems is largely unknown. This study investigated AMF communities through their spores in soil in a ‘terra firme forest’ in Central Amazonia. The contribution played by abiotic factors and plant host species identity in regulating the composition, abundance and diversity of such communities along a topographic gradient with different soils and hydrology was also evaluated. Forty-one spore morphotypes were observed with species belonging to the genera Glomus and Acaulospora, representing 44 % of the total taxa. Soil texture and moisture, together with host identity, were predominant factors responsible for shaping AMF communities along the pedo-hydrological gradient. However, the variability within AMF communities was largely associated with shifts in the relative abundance of spores rather than changes in species composition, confirming that common AMF species are widely distributed in plant communities and all plants recruited into the forest are likely to be exposed to the dominant sporulating AMF species.     

Plantation age,understory vegetation,and species‐specific traits of target seedlings alter the competition and facilitation role of Eucalyptus in South China

The Chinese government is considering ways to reconstruct Eucalyptus plantation monocultures in order to improve their ecosystem services. However, the effects of competition or facilitation of Eucalyptus on native species during the reconstruction have not been identified, especially during the formation of novel ecosystems. To better understand these relationships, in this study we tested the effects of competition and facilitation of Eucalyptus on three target species (Schima superba, Michelia macclurei, and Castanopsis fissa), in Eucalyptus plantations with different ages and understory vegetation. The results showed that the survival and growth of S. superba and M. macclurei were not sensitive to plantation age and understory removal treatment. The survival of C. fissa in understory removal was significantly higher and the growth of C. fissa increased gradually with increasing plantation age. The relative neighbor effect (RNE) index for growth indicated that the relationship between Eucalyptus and target species switched from competition to facilitation with an increase in plantation age. A redundancy analysis (RDA) showed that survival was positively correlated with soil water content and soil phosphorus. Growth was positively correlated with soil organic matter and soil nitrogen and negatively correlated with soil bulk density. Our results indicate that plantation age, understory vegetation, and species‐specific traits of target seedlings could change the competition and facilitation roles of Eucalyptus. Higher survival and growth rates indicated that C. fissa was an appropriate species for the reconstruction of mature Eucalyptus plantations and understory removal will benefit the process.     

Arbuscular mycorrhizas of plants growing in the Western Ghats region, Southern India

A survey of the arbuscular mycorrhizal (AM) status of plants growing in the Western Ghats region of Southern India was undertaken. Root and soil samples of plants growing in the four vegetation types forest, grassland, scrub, and cultivated land or plantation were examined. Of the 329 species (representing 61 families) examined, 174 were mycorrhizal. AM association was recorded in 81 species for the first time, including species from several families assumed to be non-mycorrhizal, e.g. Amaranthaceae, Capparaceae, Commelinaceae, Cyperaceae and Portulacaceae. AM fungal spores of 35 species belonging to Acaulospora, Gigaspora, Glomus, Sclerocystis and Scutellospora were recorded. AM fungal species richness was found to be highest in scrub and lowest in agricultural and plantation soils. Mean colonization levels were dependent on plant life-form, life-cycle pattern and vegetation type. Accepted: 26 October 1999     

Plant-soil feedbacks between invasive shrubs and native forest understory species lead to shifts in the abundance of mycorrhizal fungi

Aims

Non-native shrubs are important invaders of the Eastern Deciduous Forest, dramatically altering forest structure and functioning. Study of invasion mechanisms in this system has emphasized aboveground processes, and plant-soil feedbacks are relatively unexplored as a mechanism of shrub dominance. We tested whether plant-soil feedback in this habitat is affected by competition and whether arbuscular mycorrhizal fungi (AMF) are involved in plant-soil feedback.

Methods

We used a standard two-phase plant-soil feedback experiment run concurrently for each of three invasive shrub species, measuring feedback effects on AMF colonization, aboveground biomass, and the responses of native plant species in greenhouse mesocosms.

Results

Lonicera maackii and Ligustrum vulgare reduced AMF colonization of native roots, both with legacy effects (prior growth in soil) and direct effects (current growth in soil). Elaeagnus umbellata grown with natives left a legacy of increased AMF colonization of native communities.

Conclusions

Our results suggest that woody invasive species can alter the AMF associations of native plants even after the invasive is no longer present. Such consequences merit study with other native species and where environmental factors, such as light availability, might be expected to compound the effects of changes in AMF.     

Morpho-Typing and Molecular Diversity of Arbuscular Mycorrhizal Fungi in Sub-Tropical Soils of Coimbatore Region, Tamil Nadu, India

The diversity potential of arbuscular mycorrhizal fungi (AMF) in three different tropical soils of southern part of India was assessed by traditional morpho-typing of AMF-spores and by culture-independent nested-PCR of internal transcribed spacer region of ribosomal genes. The population diversity of AMF in soil was strongly correlated with available P₂O₅ in soil. Among the three different soils, black-cotton soil had more diversified AMF species than alluvial and red sandy soils. Pooled data of morpho-typing and sequence-driven analysis revealed that Glomus, Gigaspora, Scutellospora and Acaulospora are the AMF genera present in these soils. The diversity of AMF in soil differs with the mycorrhiza colonizing the plant roots.     

Seasonal differences in arbuscular mycorrhizal fungal communities in two woody species dominating semiarid caatinga forests

Tropical dry forests are strongly affected by seasonality, but its effects on belowground communities are poorly studied. Thus, the objective of this study was to reveal the effect of the season (dry versus wet) on the mycorrhizal status of roots and their potential colonization, and to determine the composition and abundance of spore-based communities of arbuscular mycorrhizal fungi (AMF) in rhizospheric soil of two dominant woody species in caatinga communities (tropical dry forest of the Brazilian Northeast). Soil and root samples were taken four times in each season (dry and wet). In the cases of the number of glomerospores and the number of infective propagules of AMF, there were significant differences between the hosts, with greater values observed in the rhizosphere of Commiphora leptophloeos than Mimosa tenuiflora. Mycorrhizal colonization and the number of infective propagules of AMF differed also between the seasons, being higher in the dry than the wet season. In total, fourteen AMF species were found in the rhizosphere of C. leptophloeos and twelve species were associated with M. tenuiflora. There was a predominance of the fungal genus Acaulospora, with seven species, followed by Gigaspora and Glomus. The species studied and the seasons differ in the composition and structure of the AMF community in the rhizosphere of the plants. The ecological significance of those differences needs to be examined further.     

粤港澳大湾区不同恢复模式植物群落结构与生态系统健康的动态变化

基于长期定位监测数据,量化揭示了红锥纯林（Castanopsis hystrix）、10种与30种乡土树种混交林等3种乡土人工林植物群落的生物量、物种多样性、生物热力学健康水平（eco-exergy）和土壤理化性状在种植后13年内的发展动态,并与尾叶桉（Eucalyptus urophylla）纯林,以及自然恢复系统（灌草坡）进行了比较。结果表明：（1）研究期间,5种恢复模式的植物群落生物量均呈现波动上升趋势,但在发展节率上有所差异。13龄时的尾叶桉纯林与两种乡土树种混交林生物量显著高于其各自1龄时的水平,且显著高于自然恢复灌草坡;相较于其他人工林,红锥纯林生物量增长缓慢,但快于灌草坡;（2）5种恢复模式植物群落的物种多样性（物种丰富度、Shannon-Wiener指数、Pielou均匀度指数）在6至13龄间均呈下降趋势,且30种乡土树种混交林下降趋势最为显著。13龄时,两种混交林Shannon-Wiener指数略高于两种纯林,显著高于灌草坡;10种乡土树种混交林的Pielou均匀度指数略高于红锥纯林与30种乡土树种混交林,显著高于尾叶桉纯林与灌草坡。（3）4种人工林的植物群落生物热力学健康水平皆在6至13龄间显著增加;13龄时两种乡土混交林群落生态显著高于两种纯林,两种纯林显著高于灌草坡,且该差异主要源自于乔木层生态的差异。（4）不同植被恢复模式中,10种乡土树种混交林土壤养分的累积效果最佳,13龄时其土壤总氮含量显著高于红锥纯林和自然恢复灌草坡,但与30种乡土树种混交林和尾叶桉纯林无显著差异。（5）冗余分析结果显示,研究期间植被与土壤间的相关关系逐步建立,土壤理化性状对地上植被结构变化的解释度由1龄时的73.3%逐步上升至13龄时的82.0%,但只有土壤有机碳含量在13龄时与地上植被结构的相关性达到显著水平。上述结果表明,乡土种人工林与外来种人工纯林群落结构、生物热力学健康水平、及植被与土壤间关系的发展规律相似,且相对而言,混交林优于纯林,纯林优于自然恢复灌草坡。植被恢复的起始物种丰富度并不是越高越好;发展到13龄时,10种乡土树种混交林在植被结构与土壤改良方面均优于30种乡土树种混交林。植被与土壤间相关关系的建立是一个长期的过程,不同植被恢复模式对土壤理化性状的差异性影响难以在短期内有所显现。     

Glomeromycotan mycorrhizal fungi from tropical Australia III. Measuring diversity in natural and disturbed habitats

Aims and Background

The aim was to investigate the diversity and distribution of Glomeromycotan fungi forming arbuscular mycorrhizal associations (AMF) in undisturbed and disturbed habitats in the vicinity of Kakadu National Park in tropical Australia. This is a tropical region with a 7–9 month dry season and a monsoonal wet season. Complimentary methods of fungus detection were used to investigate the diversity and relative dominance of AMF at a regional scale.

Methods

Soils were sampled from 32 sites, representing eucalypt savanna woodlands, wetlands, sandstone escarpment, rainforest, and disturbed mine waste rock dumps (overburden or spoil). Populations of AMF were identified and quantified using spores from soil. Morphology patterns of fungi colonising bait plant roots were examined and isolates were obtained by four complimentary pot-culturing methods.

Results

Different methods of detecting fungi produced different answers about which AMF were most important in the tested soils. In particular, spore surveys apparently underestimated the importance of Glomus species and overestimated the activity of Acaulospora species with numerous small spores, while calculated spore biovolumes overestimated the importance of Scutellospora and Gigaspora species with large spores, relative to inoculum levels of these fungus categories measured in bioassays. Spore surveys revealed 15 species of fungi and 8 additional fungi were recovered from the same soil samples using pot-culture isolation methods. Pot-cultures were especially important for detecting Glomus species that had high inoculum levels, but rarely produced spores in soils. Spores of AMF increased in abundance as vegetation developed in mine habitats reaching a peak that was higher than in undisturbed plant communities. Spore numbers (but not biovolumes) were well correlated with bioassay measurements of inoculum levels.

Conclusions

Most AMF species were widespread, but several were restricted to disturbed habitats or wetland soils. Undisturbed sites had a substantially higher diversity of AMF than partially vegetated mine waste rock dumps. It is recommended that AMF population surveys should not be based entirely on spore occurrence data, to avoid overlooking important fungi that sporulate infrequently. These fungi could be detected by bioassays or pot culture isolation from soil. Major variations in the detectability of AMF correspond to different life history strategies and can mask variations in their abundance.     

Effects of abandoned Eucalyptus plantations on lizard communities in the Brazilian Cerrado

The rapid expansion of human altered landscapes affects biodiversity on every continent. A fundamental goal of conservation biologists is to understand why certain species are at risk of extinction while others are able to persist in human altered landscapes. Afforestation, the conversion of unforested lands to planted forest, is rapidly altering many natural landscapes worldwide. In the Cerrado (Brazilian savanna), a global biodiversity hotspot, a shortage of government incentives has the landscape riddled with abandoned plantation forests that are not subject to active restoration projects. Studies investigating the impacts of abandoned plantations on biodiversity are strikingly limited. We examine the effects of abandoned Eucalyptus plantations on the structure of Cerrado lizard communities. We assessed changes in lizard capture, richness and equitability along cerrado sensu stricto—Eucalyptus transects. Our results indicate abandoned Eucalyptus plantations have subsets of Cerrado species persisting with a great loss of endemic species. The cerrado sensu stricto—Eucalyptus linear transect analysis demonstrated distance from native habitat is positively correlated with loss of biodiversity. We performed correspondence analyses to summarize the variation in species captures across different sites, habitats and pitfall array positions. These analyses depicted strong species associations between habitats and their pitfall array positions. This study is the first to show the negative impacts of abandoned Eucalyptus plantations on Cerrado lizard communities, serving as a cautionary tale of Cerrado biodiversity non-resilience in abandoned Eucalyptus plantations. Mitigation requires that abandoned Eucalyptus plantations are made more suitable to Cerrado lizards by implementing targeted habitat heterogeneity restoration.