Regeneration Of Plant Communities Research Articles

丛枝菌根真菌的生态分布及其影响因子研究进展

PDF HTML阅读 XML下载 导出引用 引用提醒 丛枝菌根真菌的生态分布及其影响因子研究进展 DOI: 10.5846/stxb201603280563 作者: 作者单位: 中国科学院生态环境研究中心,中国科学院生态环境研究中心城市与区域生态国家重点实验室,青岛农业大学资源与环境学院,中国科学院生态环境研究中心 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41371264，41071178）；城市与区域生态国家重点实验室自主方向项目（SKLURE2012-1-03） Ecological distribution of arbuscular mycorrhizal fungi and the influencing factors Author: Affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences,State Key Laboratory of Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,College of Resources and Environment,Qingdao Agricultural University,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:丛枝菌根（arbuscular mycorrhiza，AM）共生体系对于植物适应各种逆境胁迫具有重要积极作用。AM真菌还能够通过根外菌丝网络调节植物群落结构和演替，深刻影响生态系统结构和功能的稳定性。AM真菌生态生理功能的发挥主要取决于其生态适应性，明确AM真菌在不同环境中的多样性、生态适应性以及对各种生态因子的响应机制，是AM真菌资源管理、功能发掘与利用的前提。迄今为止，有关各种生态因子对AM真菌多样性的影响已有不少研究，但是AM真菌生态分布及其形成机制仍缺乏系统的研究和理论分析。综述了生物因子和非生物因子对AM真菌生态分布的影响，结合大型生物空间分布理论探讨了AM真菌生态分布规律和建成机制，分析了当前本研究领域所存在的问题和动向，以期推动相关研究进展。 Abstract:Arbuscular mycorrhizal (AM) fungi are ubiquitous soil fungi that can form symbiotic associations with the majority of terrestrial plant. AM fungi play key roles in plant resistance to various environmental stresses, such as nutrient deficiency, drought, and soil contaminations. Through the common mycorrhizal network, AM fungi can regulate plant community structure and succession, influence material cycling, energy flow, and signal transduction, and substantially affect ecosystem stability and function. Because the physiological and ecological functions of AM fungi could be predetermined by their ecological adaptability, understanding the AM fungal biodiversity in different ecosystems and their response to various environmental factors is important for the exploration and utilization of these biological resources. To date, many studies have revealed the influences of different ecological factors on AM fungal diversity, however, systematic studies on the ecological distribution patterns of AM fungi and the underlying mechanisms are still lacking. This paper summarized available knowledge regarding the influences of biotic and abiotic factors on AM fungal diversity and ecological distribution, and discussed AM fungal biogeography compared to macroorganisms. Prospects in this research area were also proposed to promote future research. 参考文献 相似文献 引证文献

Pollen distribution and deposition in mangrove sediments of the Ranong Biosphere Reserve, Thailand

Pollen analyses of surface and core sediments from the Ranong Biosphere Reserve, Ranong Province, Thailand, were carried out to determine spatial and quantitative compositional fidelities of the pollen record to achieve more accuracy in the reconstruction of past mangroves. The results reveal that many taphonomic biases from both biological and physical variables can lead to misinterpretation of the pollen records. Autochthonous pollen from true mangrove species were predominant in forest sediments, suggesting that mangrove sporomorphs are potential indicators of mangrove environments, while the frequent occurrence in low numbers of allochthonous and parautochthonous palynomorphs in mangrove sediments can reflect the regional plant communities. Close relationships between pollen from Bruguiera, Rhizophora apiculata, and Sonneratia alba and their vegetation were observed. The spatial reliability of Avicennia alba, Aegiceras corniculatum, Ceriops tagal, and Xylocarpus sp. pollen was low. The sediment cores show that the mangrove forest with its plant zonation was prograding towards the sea over time. The decline in R. apiculata pollen concentrations recovered in the upper part of all sediment cores reflects a decrease in the population of this plant taxon in the forest possibly caused by logging.

Thirty years unmanaged green roofs: Ecological research and design implications

The variations in species composition and assemblage of unmanaged simple-intensive green roofs in Hannover, Germany, were investigated over a thirty year period, in order to assess the persistence of the initial seed mixture and to evaluate floristic changes. The roofs were greened in 1985 with soil-based turf rolls sown with a mixture of five grasses (Festuca rubra, Festuca ovina, Agrostis capillaris, Lolium perenne and Poa pratensis). Three sets of 120 phytosociological relevés, sampled in 1987, 1999 and 2014, have been compared to assess: (1) nestedness vs spatial turnover, (2) functional diversity and (3) the importance of vegetation dynamics on green roof performance and design. Results demonstrated that from 1987 to 1999 the species diversity increased and the species turnover prevailed over nestedness, due to the progressive niche occupation by new species. In contrast, from 1999 to 2014 species diversity remained steady, suggesting that nestedness prevailed over species turnover. The main driver of the observed functional changes was a shift towards relatively more thermoxeric conditions. In terms of plant life strategies, the competitive species sown on the roof gradually gave way to stress-tolerant and ruderal species, along with a progressive increase in species with shortdistance seed dispersal strategies. It is concluded that: (a) to create resilient green roofs, spontaneous colonisation should be accepted and considered as a design factor; and (b) regional plant communities could serve as a model for seed recruitment and installations.

Local-scale analysis of plant community from the Early Cretaceous riparian ecosystem of Hautrage, Belgium

Diversity properties and relative taxon abundance are explored to describe plant community local-scale spatial and temporal patterns during four ecological stages from the middle Barremian continental aquatic ecosystem of Hautrage, Mons basin, western Belgium. Taxon co-occurrence and correlations of taxon abundance are also analyzed to describe the main patterns of plant association within each stage and through time. Diversity, relative taxon abundance and taxonomic inventory greatly vary laterally and between ecological stages. Two of these stages show gradients in taxon richness and abundance reflecting probable edge effects. A reconstruction of the plant community evolution based on these four stages plus seven previously reported stages reveal a plant community mainly composed of the conifers Arctopitys, Brachyphyllum, Frenelopsis, and Pagiophyllum, and the ferns Gleichenites and Phlebopteris, maintained through time. Two main taxon association patterns are observed over space and time: 1) Arctopitys and Phlebopteris, and 2) Brachyphyllum, Gleichenites, Pagiophyllum. Conifer type 1, Elatides and Sphenopteris appear to have been spatially associated, whereas inverse relations between Cladophlebis and Phlebopteris and between Onychiopsis and Sphenopteris reflect possible niche overlap and competitive exclusion pressures. Three different successional stages are identified by the proportion of herbaceous and woody taxa and the presence/absence of Frenelopsis. Frenelopsis was a dominant taxon in mature community stages probably forming closed canopies, and having a negative effect on richness and abundance of other taxa. Our results evidence four intense and two less intense fire events through the series, suggesting that wildfires played an important role in the ecological succession of the plant community of Hautrage. Weichselia reticulata most probably played a key role in early successional stages, contributing in the regeneration of plant communities after wildfire disturbance events.

Recovery of Mediterranean Vegetation after Recurrent Forest Fires: Insight from the 2010 Forest Fire on Mount Carmel, Israel

AbstractThe December 2010 forest fire on Mount Carmel – the largest recorded in Israel – burned about 2500 ha of Mediterranean forest. We documented the immediate and short‐term changes of the vegetation following this fire. Relative vegetation cover and plant species richness were sampled in five sites in spring 2009 and 2010, prior to the fire, and were re‐sampled in 2011 and 2012. The number of recurrent fires (between 0 and 3) and time intervals between fires were documented for each site. We observed a strong decrease in total vegetation cover, associated with reduction of relative cover of woody vegetation. In the second year after the fire, shrubs and dwarf shrubs became dominant at all sites. Time intervals between fires played an important role in determining the extent of regeneration of the vegetation cover and plant species richness. Plant species richness immediately decreased after the fire in sites with a short fire interval, while in sites with a long fire interval, plant species richness increased. Relative plant cover was associated with the time from the last previous fire, and this association differed among different plant groups. These results suggest that vegetation and plant community regeneration after recurrent fires is accelerated when time intervals between fires are longer, whereas high fire frequency may suppress vegetation regeneration. Based on the results, we propose that forest regeneration after recurrent fires depends largely on time from the previous fire, rather than on the number of previous fires. Copyright © 2015 John Wiley & Sons, Ltd.

Is the positive response of seed germination to plant-derived smoke associated with plant traits?

Relationships between seed germination response to plant-derived smoke and various plant traits (habitat requirements, life form, seed morphology, seed bank type) were analysed for 97 species of the Hungarian flora using published data. It was hypothesized that smoke-responsive species – those displaying enhanced germination in response to smoke – differ from non-responsive species – smoke having an indifferent or inhibitory effect on germination – in habitat requirements and/or certain life history traits. To our knowledge, no such comparison has previously been reported for a European flora. We found that species indicating disturbance and those preferring soils rich or moderately rich in nitrogen were more frequent in the smoke-responsive group (80% and 41%, respectively) than in the non-responsive group, while the non-responsive group contained a high percentage of natural species (i.e. species dominant or characteristic in natural plant communities; 47%) and species indicative of nutrient poor (38%) or (sub)mesotrophic (38%) soils. Annuals or biennials (67%) dominated the smoke-responsive group, whereas in the non-responsive group these short-lived species and perennial herbs were equally abundant (43% each). There was a tendency for higher frequency of long-term persistent seed bank among smoke-responsive species (78%) than in the non-responsive group (54%). These findings suggest that smoke-stimulated germination is associated with only a few specific plant traits for species from a semiarid temperate region of Europe, but highlight the frequent occurrence of smoke-enhanced germination among short-lived, nitrophilous or disturbance tolerant species. These results can contribute to a better understanding of post-fire regeneration of plant communities, and could also be considered during vegetation restoration or weed management.

Season of fire manipulates bud bank dynamics in northern mixed-grass prairie

In perennial grassland dominated systems, belowground bud banks regulate plant community dynamics. Plant community responses to disturbance are largely driven by the ability to generate future aboveground growth originating from belowground axillary buds. This study examined bud bank dynamics for Bouteloua gracilis, Hesperostipa comata, and Pascopyrum smithii following fire in northwestern mixed-grass prairie in eastern Montana, USA. Belowground axillary buds were counted and classified for three growing seasons to determine immediate and short-term effects of summer, fall, and spring prescribed burns on patterns of bud bank activity, dormancy, and mortality. Prescribed burns did not result in immediate mortality of B. gracilis, H. comata, or P. smithii buds. Surprisingly, spring prescribed burns immediately increased the number of active B. gracilis buds. Summer fire, however, reduced B. gracilis active bud numbers. Fall burns immediately activated P. smithii buds, whereas fire did not influence any immediate bud dynamics for H. comata. Reduced bud numbers of H. comata may limit the ability to respond to fire. Season of fire directly manipulated bud activity, dormancy, and mortality for these species throughout the growing and dormant seasons following fire. Using season of fire to manipulate bud bank dynamics illustrates potential to improve post-fire management strategies based on known bud development trajectories and bud dynamics following fire.

Responses of plant community composition and biomass production to warming and nitrogen deposition in a temperate meadow ecosystem.

Climate change has profound influences on plant community composition and ecosystem functions. However, its effects on plant community composition and biomass production are not well understood. A four-year field experiment was conducted to examine the effects of warming, nitrogen (N) addition, and their interactions on plant community composition and biomass production in a temperate meadow ecosystem in northeast China. Experimental warming had no significant effect on plant species richness, evenness, and diversity, while N addition highly reduced the species richness and diversity. Warming tended to reduce the importance value of graminoid species but increased the value of forbs, while N addition had the opposite effect. Warming tended to increase the belowground biomass, but had an opposite tendency to decrease the aboveground biomass. The influences of warming on aboveground production were dependent upon precipitation. Experimental warming had little effect on aboveground biomass in the years with higher precipitation, but significantly suppressed aboveground biomass in dry years. Our results suggest that warming had indirect effects on plant production via its effect on the water availability. Nitrogen addition significantly increased above- and below-ground production, suggesting that N is one of the most important limiting factors determining plant productivity in the studied meadow steppe. Significant interactive effects of warming plus N addition on belowground biomass were also detected. Our observations revealed that environmental changes (warming and N deposition) play significant roles in regulating plant community composition and biomass production in temperate meadow steppe ecosystem in northeast China.

A ∼50 ka record of monsoonal variability in the Darjeeling foothill region, eastern Himalayas

Pollen, phytoliths and δ 13C signatures of soil organic matter from two fluvial sedimentary sequences of the Darjeeling foothill region, eastern Himalayas are used to portray palaeoclimatic oscillations and their impact on regional plant communities over the last ∼50ka. Quantitative palaeoclimate estimation using coexistence approach on pollen data and other proxies indicate significant oscillations in precipitation during the late part of MIS 3 (46.4–25.9ka), early and middle part of MIS 2 (25.9–15.6ka), and 5.4 to 3.5ka. Middle to late MIS 3 (ca 46.4–31ka.) was characterized by a comparatively low monsoonal activity and slightly higher temperature than that during ca 31ka onwards. Simultaneous expansion of deciduous trees and chloridoid grasses also imply a drier and warmer phase. Between 31 and 22.3ka (late MIS 3 to mid-MIS 2), higher precipitation and a slightly cooler temperature led to an increase in evergreen elements over deciduous taxa and wet-loving panicoid grasses over dry-loving chloridoid grasses than earlier. After ca 22.3ka, shrinking of forest cover, expansion of C4 chloridoid grasses, Asteraceae and Cheno-ams in the vegetation with lowering of temperature and precipitation characterized the onset of the LGM which continued till 18.3ka. End of the LGM is manifested by a restoration in the forest cover and in the temperature and precipitation regime. Later, during 5.4 to 4.3ka, a strong monsoonal activity supported a dense moist evergreen forest cover that subsequently declined during 4.3 to 3.5ka. A further increase in deciduous elements and non-arboreals might be a consequence of reduced precipitation and higher temperature during this phase. A comparison between monsoonal rainfall, MAT and palaeoatmospheric CO2 with floral dynamics since last ∼50ka indicates that these fluctuations in plant succession were mainly driven by monsoonal variations.

Risk of extinction of plant communities: Risk and assessment categories

There are many proposals for the assessment of plant communities, based on different criteria, but very few proposals for categorization of the risk of extinction of plant communities (syntaxa). In this paper, concepts related to extent of occurence (EOO), area of occupancy (AOO), extinction and regeneration of plant communities are defined. Also, we propose and define several ranks of extinction risk based on quantitative criteria of the EOO, AOO and processes of decline. The proposals are global, for application to any type of cormophytic vegetation, without geographical restrictions. To check the adequacy of the proposed ranks and its thresholds, the method has been applied to the vegetation of the Iberian Peninsula based on the EOO (122 plant communities) and the AOO (2224 plant communities).

Effects of arbuscular mycorrhizal fungi on plant growth depend on root system: a meta-analysis

Our aim was to explore the way that root system type affects mycorrhizal growth response of plants. An extensive meta-analysis with 943 peer-review publications was conducted to test the difference in mycorrhizal responses between taproot plants and plants with a fibrous root system. We found that taproot plants showed greater growth response (biomass, P and N uptake) to colonization by arbuscular mycorrhizal fungi (AMF) than do plant species with fibrous root systems. This response pattern was dependent on stress types, AMF identity and species richness, and particularly the type of stress (abiotic vs. biotic). Taproot plants respond more to AMF than plants with a fibrous root system; but no difference was shown under biotic stress. The interaction effect seen for AMF and biotic stress was significantly higher for plants with fibrous root system, but was not significant between taproot plants and abiotic stress. Difference in biomass response was only found for Glomeraceae and Gigasporaceae between the two types of plants, while difference was found in P uptake response for Glomeraceae and Claroideoglomeraceae. However, plants with fibrous root system showed higher growth response than taproot plants under nematode stress. Taproot plants might be more dependent on mycorrhiza than plants with fibrous root system. This indicates that environmental conditions can modify the relative abundance of taproot plants and plants with fibrous root system through mycorrhizal functioning, which will regulate plant community dynamics and processes.

Seeds: the ecology of regeneration in plant communities

Seeds: the ecology of regeneration in plant communities

Cerrado vegetation and global change: the role of functional types, resource availability and disturbance in regulating plant community responses to rising CO2 levels and climate warming

The cerrado is the most extensive savanna ecosystem of South America and a biodiversity hotspot, harboring a diverse flora (>7,000 species) with high levels of endemism. More than 50 % of the cerrado’s approximately 2 million km2 has been converted into pasture and agricultural lands and it is uncertain how the remaining areas will respond to increasing pressures from land use and climate change. Interactions between disturbance regime and resource (water and nutrient) availability are known to determine the distribution of the various plant communities, of contrasting structure and composition, which coexist in the region. We discuss how fire, nutrients and species traits regulate plant community responses to rising CO2 and global warming, exploring constraints to forest expansion into savanna environments. We describe how climate change will likely reverse a natural process of forest expansion, observed in the region over the past few millennia, accelerating tree cover loss through feedbacks involving fire and resource limitation, and counteracting expected CO2 stimulation effects. These involve changes in fundamental processes occurring above and below ground, which will probably also impact species performance, distribution and biodiversity patterns. We propose a conceptual framework for predicting changes on vegetation structure, highlighting the need for mechanistic models to accurately simulate vegetation dynamics under climate change scenarios. We conclude by explaining why an effective research agenda must necessarily include mitigation efforts, aimed at minimizing impacts of land clearing through enforced conservation and restoration policies in natural and managed ecosystems.

Post-fire salvage logging alters species composition and reduces cover, richness, and diversity in Mediterranean plant communities

An intense debate exists on the effects of post-fire salvage logging on plant community regeneration, but scant data are available derived from experimental studies. We analyzed the effects of salvage logging on plant community regeneration in terms of species richness, diversity, cover, and composition by experimentally managing a burnt forest on a Mediterranean mountain (Sierra Nevada, S Spain). In each of three plots located at different elevations, three replicates of three treatments were implemented seven months after the fire, differing in the degree of intervention: “Non-Intervention” (all trees left standing), “Partial Cut plus Lopping” (felling 90% of the trees, cutting the main branches, and leaving all the biomass in situ), and “Salvage Logging” (felling and piling the logs, and masticating the woody debris). Plant composition in each treatment was monitored two years after the fire in linear point transects. Post-fire salvage logging was associated with reduced species richness, Shannon diversity, and total plant cover. Moreover, salvaged sites hosted different species assemblages and 25% lower cover of seeder species (but equal cover of resprouters) compared to the other treatments. Cover of trees and shrubs was also lowest in Salvage Logging, which could suggest a potential slow-down of forest regeneration. Most of these results were consistent among the three plots despite plots hosting different plant communities. Concluding, our study suggests that salvage logging may reduce species richness and diversity, as well as the recruitment of woody species, which could delay the natural regeneration of the ecosystem.

Soil pathogen communities associated with native and non-native Phragmites australis populations in freshwater wetlands.

Soil pathogens are believed to be major contributors to negative plant–soil feedbacks that regulate plant community dynamics and plant invasions. While the theoretical basis for pathogen regulation of plant communities is well established within the plant–soil feedback framework, direct experimental evidence for pathogen community responses to plants has been limited, often relying largely on indirect evidence based on above-ground plant responses. As a result, specific soil pathogen responses accompanying above-ground plant community dynamics are largely unknown. Here, we examine the oomycete pathogens in soils conditioned by established populations of native noninvasive and non-native invasive haplotypes of Phragmites australis (European common reed). Our aim was to assess whether populations of invasive plants harbor unique communities of pathogens that differ from those associated with noninvasive populations and whether the distribution of taxa within these communities may help to explain invasive success. We compared the composition and abundance of pathogenic and saprobic oomycete species over a 2-year period. Despite a diversity of oomycete taxa detected in soils from both native and non-native populations, pathogen communities from both invaded and noninvaded soils were dominated by species of Pythium. Pathogen species that contributed the most to the differences observed between invaded and noninvaded soils were distributed between invaded and noninvaded soils. However, the specific taxa in invaded soils responsible for community differences were distinct from those in noninvaded soils that contributed to community differences. Our results indicate that, despite the phylogenetic relatedness of native and non-native P. australis haplotypes, pathogen communities associated with the dominant non-native haplotype are distinct from those of the rare native haplotype. Pathogen taxa that dominate either noninvaded or invaded soils suggest different potential mechanisms of invasion facilitation. These findings are consistent with the hypothesis that non-native plant species that dominate landscapes may “cultivate” a different soil pathogen community to their rhizosphere than those of rarer native species.

Seasonal Dynamics of the Plant Community and Soil Seed Bank along a Successional Gradient in a Subalpine Meadow on the Tibetan Plateau

BackgroundKnowledge about how change the importance of soil seed bank and relationship between seed mass and abundance during vegetation succession is crucial for understanding vegetation dynamics. Many studies have been conducted, but their ecological mechanisms of community assembly are not fully understood.MethodologyWe examined the seasonal dynamics of the vegetation and soil seed bank as well as seed size distribution along a successional gradient. We also explored the potential role of the soil seed bank in plant community regeneration, the relationship between seed mass and species abundance, and the relative importance of deterministic and stochastic processes along a successional gradient.Principal FindingsSpecies richness of seed bank increased (shallow layer and the total) and seed density decreased (each layer and the total) significantly with succession. Species richness and seed density differed significantly between different seasons and among soil depths. Seed mass showed a significant negative relationship with relative abundance in the earliest successional stage, but the relationships were not significant in later stages. Seed mass showed no relationship with relative abundance in the whole successional series in seed bank. Results were similar for both July 2005 and April 2006.ConclusionsThe seed mass and abundance relationship was determined by a complex interaction between small and larger seeded species and environmental factors. Both stochastic processes and deterministic processes were important determinants of the structure of the earliest stage. The importance of seed bank decreased with succession. The restoration of abandoned farmed and grazed meadows to the species-rich subalpine meadow in Tibetan Plateau can be successfully achieved from the soil seed bank. However, at least 20 years are required to fully restore an abandoned agricultural meadow to a natural mature subalpine meadow.

Temporal dynamics of plant community regeneration sources during tallgrass prairie restoration

Ecological restoration aims to augment and steer the composition and contribution of propagules for community regeneration in degraded environments. We quantified patterns in the abundance, richness, and diversity of seed and bud banks across an 11-year chronosequence of restored prairies and in prairie remnants to elucidate the degree to which the germinable seed bank, emerged seedlings, belowground buds, and emerged ramets were related to community regeneration. There were no directional patterns in the abundance, richness, or diversity of the germinable seed bank across the chronosequence. Emerged seedling abundance of sown species decreased during restoration. Richness and diversity of all emerged seedlings and non-sown emerged seedling species decreased across the chronosequence. Conversely, abundance and richness of belowground buds increased with restoration age and belowground bud diversity of sown species increased across the chronosequence. Numbers of emerged ramets also increased across the chronosequence and was driven primarily by the number of graminoid ramets. There were no temporal changes in abundance and richness of sown and non-sown emerged ramets, but diversity of sown emerged ramets increased across the chronosequence. This study demonstrates that after initial seeding, plant community structure in restored prairies increasingly reflects the composition of the bud bank.

Invasive feral pigs impact native tree ferns and woody seedlings in Hawaiian forest

Invasive mammals can fundamentally alter native plant communities, especially on isolated islands where plants evolved without them. The globally invasive feral pig (Sus scrofa) can be particularly destructive to native plant communities. Tree ferns are an important understory component in many forests facilitating the establishment of a variety of species. However, the extent and effects of feral pig damage to tree ferns, and associated impacts on plant community regeneration, are largely unknown. We quantified the effect that feral pig damage has on tree fern growth, survival, and epiphytic woody seedling abundance over 1 year on 438 randomly selected tree ferns of three endemic species (Cibotium chamissoi, Cibotium glaucum, and Cibotium menziesii) in a Hawaiian montane wet forest with high tree fern and feral pig densities. Across all tree fern species, feral pigs damaged 13 % of individuals over 1 year. Compared with undamaged tree ferns, moderately- to heavily-damaged individuals had decreases of 4 to 27 % in trunk length increment and lost tenfold more fronds. Tree fern angle (standing, leaning, prone, or semi-prone) and woody seedling abundance co-varied with feral pig damage. Specifically, damaged tree ferns were more often prone or semi-prone and supported more seedlings, but also had annual mortality up to 34 % higher than undamaged tree ferns. Overall, feral pig damage had substantial negative effects on tree ferns by reducing growth and survival. Given the importance of tree ferns as regeneration sites for a variety of native plants, feral pig damage to tree ferns will likely alter future forest composition and structure. Specifically, feral pig damage to tree ferns reduces potential establishment sites for species that either regenerate preferentially as epiphytes or are currently restricted to epiphytic establishment due to ground rooting by feral pigs.

Vegetation recovery and plant facilitation in a human-disturbed lava field in a megacity: searching tools for ecosystem restoration

Unplanned urban development threatens natural ecosystems. Assessing ecosystem recovery after anthropogenic disturbances and identifying plant species that may facilitate vegetation regeneration are critical for the conservation of biodiversity and ecosystem services in urban areas. At the periphery of Mexico City, illegal human settlements produced different levels of disturbance on natural plant communities developed on a lava field near the Ajusco mountain range. We assessed natural regeneration of plant communities 20 years after the abandonment of the settlements, in sites that received low (manual harvesting of non-timber forest products), medium (removal of aboveground vegetation), and high (removal of substrate and whole vegetation) disturbance levels. We also tested the potential facilitative role played by dominant tree and shrub species. Plant diversity and vegetation biomass decreased as disturbance level increased. Sites with high disturbance level showed poor regeneration and the lowest species similarity compared to the least disturbed sites. Six dominant species (i.e., those with the highest abundance, frequency, and/or basal area) were common to all sites. Among them, three species (the tree Buddleja cordata, and two shrubs, Ageratina glabrata and Sedum oxypetalum) were identified as potential facilitators of community regeneration, because plant density and species richness were significantly higher under their canopies than at open sites. We propose that analyzing community structural traits of the successional vegetation (such as species diversity and biomass) and identifying potential facilitator species are useful steps in assessing the recovery ability of plant communities to anthropogenic disturbances, and in designing restoration strategies.

Regeneration of Different Plant Functional Types in a Masson Pine Forest Following Pine Wilt Disease

Pine wilt disease is a severe threat to the native pine forests in East Asia. Understanding the natural regeneration of the forests disturbed by pine wilt disease is thus critical for the conservation of biodiversity in this realm. We studied the dynamics of composition and structure within different plant functional types (PFTs) in Masson pine forests affected by pine wilt disease (PWD). Based on plant traits, all species were assigned to four PFTs: evergreen woody species (PFT1), deciduous woody species (PFT2), herbs (PFT3), and ferns (PFT4). We analyzed the changes in these PFTs during the initial disturbance period and during post-disturbance regeneration. The species richness, abundance and basal area, as well as life-stage structure of the PFTs changed differently after pine wilt disease. The direction of plant community regeneration depended on the differential response of the PFTs. PFT1, which has a higher tolerance to disturbances, became dominant during the post-disturbance regeneration, and a young evergreen-broad-leaved forest developed quickly after PWD. Results also indicated that the impacts of PWD were dampened by the feedbacks between PFTs and the microclimate, in which PFT4 played an important ecological role. In conclusion, we propose management at the functional type level instead of at the population level as a promising approach in ecological restoration and biodiversity conservation.