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Intraspecific variation can have a major impact on plant community composition yet there is little information available on the extent that such variation by an already established species affects interspecific interactions of an invading species. The current research examined the competitiveness of clones of a globally rare but locally common native grass, Calamagrostis porteri ssp. insperata to invasion by Alliaria petiolata, a non‐native invasive species. A greenhouse experiment was conducted twice over consecutive years in which 15 clones from three populations of Calamagrostis were paired with rosettes of Alliaria in pots containing native forest soil previously uninvaded by Alliaria. Both species showed a negative response to the presence of the other species, although Alliaria more so than Calamagrostis. Moreover, the effect of Calamagrostis depended upon population, and, to a lesser extent, the individual clone paired with Alliaria. Competitive effects were stronger in the first experiment compared with when the experiment was repeated in the second year. The influence of Calamagrostis clones on the outcome of the experiment varied among populations and among clones, but also between years. Clones from one of the three populations were more influential than clones from the other two populations. Only one of 15 clones, both from the same population, was influential in both experiments. This research supports a growing literature indicating that intraspecific variability among clones of a dominant species can affect interspecific interactions and that such variability in a native species can affect performance of an invading species. 相似文献
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The symbiosis between land plants and arbuscular mycorrhizal fungi (AMF) is one of the most widespread and ancient mutualisms on the planet. However, relatively little is known about the evolution of these symbiotic plant–fungal interactions in natural communities. In this study, we investigated the symbiotic AMF communities of populations of the native plant species Pilea pumila (Urticaceae) with varying histories of coexistence with a nonmycorrhizal invasive species, Alliaria petiolata (Brassicaceae), known to affect mycorrhizal communities. We found that native populations of P. pumila with a long history of coexistence with the invasive species developed more diverse symbiotic AMF communities. This effect was strongest when A. petiolata plants were actively growing with the natives, and in soils with the longest history of A. petiolata growth. These results suggest that despite the ancient and widespread nature of the plant–AMF symbiosis, the plant traits responsible for symbiotic preferences can, nevertheless, evolve rapidly in response to environmental changes. 相似文献
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S. Footitt Z. Huang H. Ölcer‐Footitt H. Clay W. E. Finch‐Savage 《Plant biology (Stuttgart, Germany)》2018,20(4):682-690
- The impact of global warming on seed dormancy loss and germination was investigated in Alliaria petiolata (garlic mustard), a common woodland/hedgerow plant in Eurasia, considered invasive in North America. Increased temperature may have serious implications, since seeds of this species germinate and emerge at low temperatures early in spring to establish and grow before canopy development of competing species.
- Dormancy was evaluated in seeds buried in field soils. Seedling emergence was also investigated in the field, and in a thermogradient tunnel under global warming scenarios representing predicted UK air temperatures through to 2080.
- Dormancy was simple, and its relief required the accumulation of low temperature chilling time. Under a global warming scenario, dormancy relief and seedling emergence declined and seed mortality increased as soil temperature increased along a thermal gradient. Seedling emergence advanced with soil temperature, peaking 8 days earlier under 2080 conditions.
- The results indicate that as mean temperature increases due to global warming, the chilling requirement for dormancy relief may not be fully satisfied, but seedling emergence will continue from low dormancy seeds in the population. Adaptation resulting from selection of this low dormancy proportion is likely to reduce the overall population chilling requirement. Seedling emergence is also likely to keep pace with the advancement of biological spring, enabling A. petiolata to maintain its strategy of establishment before the woodland canopy closes. However, this potential for adaptation may be countered by increased seed mortality in the seed bank as soils warm.
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Alexandra G. Lodge Timothy J. S. Whitfeld Alexander M. Roth Peter B. Reich 《植被学杂志》2018,29(4):746-755
Questions
Predicting which newly arrived species will establish and become invasive is a problem that has long vexed researchers. In a study of cold temperate oak forest stands, we examined two contrasting hypotheses regarding plant functional traits to explain the success of certain non‐native species. Under the “join the locals” hypothesis, successful invaders are expected to share traits with resident species because they employ successful growth strategies under light‐limited understorey conditions. Instead, under the “try harder” hypothesis, successful invaders are expected to have traits different from native species in order to take advantage of unused niche space.Location
Minnesota, USA.Methods
We examined these two theories using 109 native and 11 non‐native plants in 68 oak forest stands. We focused on traits related to plant establishment and growth, including specific leaf area (SLA), leaf carbon‐to‐nitrogen ratio (C:N), wood density, plant maximum height, mycorrhizal type, seed mass and growth form. We compared traits of native and non‐native species using ordinations in multidimensional trait space and compared community‐weighted mean (CWM) trait values across sites.Results
We found few differences between trait spaces occupied by native and non‐native species. Non‐native species occupied smaller areas of trait space than natives, yet were within that of the native species, indicating similar growth strategies. We observed a higher proportion of non‐native species in sites with higher native woody species CWM SLA and lower CWM C:N. Higher woody CWM SLA was observed in sites with higher soil pH, while lower CWM C:N was found in sites with higher light levels.Conclusions
Non‐native plants in this system have functional traits similar to natives and are therefore “joining the locals.” However, non‐native plants may possess traits toward the acquisitive end of the native plant trait range, as evidenced by higher non‐native plant abundance in high‐resource environments.6.
Sandra Stålhandske Martin Olofsson Karl Gotthard Johan Ehrlén Christer Wiklund Olof Leimar 《Biological journal of the Linnean Society. Linnean Society of London》2016,119(4):1060-1067
An insect species that shows variation in host species association across its geographical range may do so either because of local adaptation in host plant preference of the insect or through environmentally or genetically induced differences in the plants, causing variation in host plant suitability between regions. In the present study, we experimentally investigate the host plant preference of Anthocharis cardamines (orange tip butterfly) in two populations from the UK and two from Sweden. Previous reports indicate that A. cardamines larvae are found on different host plant species in different regions of the UK, and some variation has been reported in Sweden. Host plant choice trials showed that females prefer to oviposit on plants in an earlier phenological stage, as well as on larger plants. When controlling for plant phenological stage and size, the host species had no statistically significant effect on the choice of the females. Moreover, there were no differences in host plant species preference among the four butterfly populations. Based on our experiment, the oviposition choice by A. cardamines mainly depends on the phenological stage and the size of the host plant. This finding supports the idea that the geographical patterns of host–plant association of A. cardamines in the UK and Sweden are consequences of the phenology and availability of the local hosts, rather than regional genetic differences in the host species preference of the butterfly. 相似文献
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Lauren M. Smith‐Ramesh 《Ecology letters》2018,21(5):646-654
Plant–soil feedback (PSF) can structure plant communities, promoting coexistence (negative PSF) or monodominance (positive PSF). At higher trophic levels, predators can alter plant community structure by re‐allocating resources within habitats. When predator and plant species are spatially associated, predators may alter the outcome of PSF. Here, I explore the influence of plant‐associated predators on PSF using a generalised cellular automaton model that tracks nutrients, plants, herbivores and predators. I explore key contingencies in plant–predator associations such as whether predators associate with live vs. senesced vegetation. Results indicate that plant‐associated predators shift PSF to favour the host plant when predators colonise live vegetation, but the outcome of PSF will depend upon plant dispersal distance when predators colonise dead vegetation. I apply the model to two spider‐associated invasive plants, finding that spider predators should shift PSF dynamics in a way that inhibits invasion by one forest invader, but exacerbates invasion by another. 相似文献
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Sohyun Woo;Tae-Min Kim;Yousuk Kim;Seorin Jeong;Eunsuk Kim; 《Ecology and evolution》2024,14(10):e70496
While invasive success of alien plant species is often attributed to their superior competitive abilities, it is also suggested that competitive ability depends on the target species of competition and resource availability. In addition, it remains unclear whether invaders and co-occurring plants in the introduced area exhibit distinctive inter- and intraspecific competitive intensities. This study aimed to evaluate the competitive ability of a successful invader, Lactuca serriola, through a combination of field surveys and a growth chamber experiment. First, we assessed biodiversity and the biomass of co-occurring plants in both L. serriola-invaded and uninvaded plots across nine sites in South Korea. Subsequently, a pairwise competition experiment was conducted between L. serriola and three weedy plant species commonly found in the invaded plots, Chenopodium album, Erigeron canadensis, and Oenothera biennis, under differential nutrient levels. Diversity indices of plant communities and the biomass of most co-occurring plants showed no significant difference between invaded and uninvaded plots. L. serriola and testing weedy plants exhibited mutually negative effects on biomass when grown together in the same pot, with the intensity of interspecific competition being comparable across nutrient treatments. Notably, intraspecific competition of L. serriola was weaker than testing weedy plants, particularly manifest in the high-nutrient treatment. The results of both field and growth-chamber studies demonstrated that L. serriola was not a particularly strong competitor compared to its neighboring weedy plants. Its successful invasion can be partially attributed to its weak intraspecific competition intensity, which potentially facilitate successful establishment with high density. 相似文献
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Thomas W. Sherry Matthew D. Johnson Kelly A. Williams Jordana D. Kaban Caroline K. McAvoy Amanda M. Hallauer Shannon Rainey Sen Xu 《Journal of Field Ornithology》2016,87(3):273-292
Diets reflect important ecological interactions, but are challenging to quantify for foliage‐gleaning birds. We used regurgitated stomach samples from five primarily insectivorous species of long‐distance migrant warblers (Parulidae) wintering in two moderate‐elevation shade coffee farms in Jamaica to assess both foraging opportunism and prey resource partitioning. Our results, based primarily on 6120 prey items in 80 stomach samples collected during a one‐week period in March 2000, confirm opportunism. The diets of all five warblers, including American Redstarts (Setophaga ruticilla), Black‐and‐White Warblers (Mniotilta varia), Black‐throated Blue Warblers (S. caerulescens), Northern Parulas (S. americana), and Prairie Warblers (S. discolor), overlapped strongly based on consumption of the same prey types, even many of the same prey species (4 of 10 interspecific overlaps >0.9, range = 0.74–0.97). Moreover, all five species fed on similarly small, often patchily distributed prey, including coffee berry borers (Hypothenemus hampei; Coleoptera, Curculionidae). Nonetheless, permutational multivariate analysis of variance also revealed that the diets of these species differed significantly, primarily with respect to prey mobility (winged vs. sessile); American Redstarts fed on the most mobile prey, and Northern Parulas on the least mobile prey and a relatively restricted set of prey taxa compared to the other four species of warblers. Overall, our results suggest both dietary opportunism consistent with a migratory life‐history, and interspecific resource partitioning consistent with differences in morphology and foraging behavior during a food‐limited season. Having provided evidence of the three necessary conditions, namely intraspecific competition, resource limitation, and interspecific overlap in resource use, the results of our study, in combination with those of other studies, also provide evidence of interspecific competition among wintering migrant insectivores. We thus argue that diffuse interspecific exploitative food competition may be more important than previously recognized. 相似文献
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Michael J. Leahy Ivan W. Vining Jason L. Villwock Raenhard O. Wesselschmidt III Andrea N. Schuhmann John A. Vogel David Y. Shieh Calvin J. Maginel III 《Restoration Ecology》2018,26(4):686-693
Lonicera maackii (Amur honeysuckle) is a non‐native species that has invaded forest stands throughout the eastern United States. This research examined using aerially applied glyphosate in autumn 2013 to control L. maackii in oak‐hickory forest stands in Missouri, U.S.A. We targeted the spraying time period when L. maackii was still green and most native plants were dormant. Across treatment units, the mean difference in L. maackii stem density significantly declined (p = 0.004) by 5.4 stems per plot from spring 2013 to summer 2014 when compared to control units which increased by 1.8 stems per plot. Treated units with a high initial infestation level of L. maackii (>50% cover) had a significant (p = 0.004) decline in the mean difference in L. maackii cover of ?50.0% per plot between spring 2013 and summer 2014 compared to an average increase of 9.2% in the controls. Similar results were found for treated units with a low initial infestation level of L. maackii (10–50% cover). Mortality of native overstory and understory trees post‐treatment was negligible. In the ground layer of forest stands with a low initial L. maackii infestation level, native non‐spray‐sensitive forb cover per plot significantly increased (p = 0.023) relative to controls between summer 2013 and summer 2014 while native spray‐sensitive species cover significantly decreased (p = 0.021) during the same period. These results suggest that an aerial application of glyphosate can provide an L. maackii control option, but with trade‐offs in compositional shifts in the native ground‐layer vegetation. 相似文献
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Intraspecific variation is central to our understanding of evolution and population ecology, yet its consequences for community ecology are poorly understood. Animal personality – consistent individual differences in suites of behaviours – may be particularly important for trophic dynamics, where predator personality can determine activity rates and patterns of attack. We used mesocosms with aquatic food webs in which the top predator (dragonfly nymphs) varied in activity and subsequent attack rates on zooplankton, and tested the effects of predator personality. We found support for four hypotheses: (1) active predators disproportionately reduce the abundance of prey, (2) active predators select for predator‐resistant prey species, (3) active predators strengthen trophic cascades (increase phytoplankton abundance) and (4) active predators are more likely to cannibalise one another, weakening all other trends when at high densities. These results suggest that intraspecific variation in predator personality is an important determinant of prey abundance, community composition and trophic cascades. 相似文献
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为筛选替代控制紫茎泽兰的本地植物及探讨提高替代控制效率的方法,通过盆栽实验并利用相对产量(RY)和竞争攻击力系数(A)衡量了3种本地植物与紫茎泽兰的竞争关系,同时评估了活性炭(AC)、杀真菌剂(FC)和二者联合(AC+FC)对它们竞争的影响。结果表明：(1)不添加任何物质条件下：紫茎泽兰与南酸枣混种时,紫茎泽兰的生物量明显高于单种(P<0.05),其RY和A分别显著大于1和0(P<0.05);紫茎泽兰分别与假地豆和狗尾草混种时,紫茎泽兰的株高和生物量均明显低于单种(P<0.05),其RY和A均分别显著小于1和0(P<0.05)。说明紫茎泽兰的竞争力强于南酸枣而弱于假地豆和狗尾草,假地豆和狗尾草可以在一定区域作为替代控制紫茎泽兰的潜在目标植物。(2)与不添加任何物质相比,紫茎泽兰与南酸枣混种时,AC、FC及AC+FC处理增加了紫茎泽兰的根冠比,降低了其地上生物量比,也降低了南酸枣的生物量(P<0.05);紫茎泽兰与假地豆混种时,AC和AC+FC处理增加了假地豆的株高和生物量,FC处理增加了紫茎泽兰的株高(P<0.05);紫茎泽兰与狗尾草混种时,AC和A... 相似文献
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Kerry Bohl Stricker Philip F. Harmon Erica M. Goss Keith Clay S. Luke Flory 《Ecology letters》2016,19(4):469-477
Emerging pathogens are a growing threat to human health, agriculture and the diversity of ecological communities but may also help control problematic species. Here we investigated the diversity, distribution and consequences of emerging fungal pathogens infecting an aggressive invasive grass that is rapidly colonising habitats throughout the eastern USA. We document the recent emergence and accumulation over time of diverse pathogens that are members of a single fungal genus and represent multiple, recently described or undescribed species. We also show that experimental suppression of these pathogens increased host performance in the field, demonstrating the negative effects of emerging pathogens on invasive plants. Our results suggest that invasive species can facilitate pathogen emergence and amplification, raising concerns about movement of pathogens among agricultural, horticultural, and wild grasses. However, one possible benefit of pathogen accumulation is suppression of aggressive invaders over the long term, potentially abating their negative impacts on native communities. 相似文献
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以外来入侵植物南美蟛蜞菊和本地近缘种蟛蜞菊为对象,通过温室模拟3种水位波动模式(水位无波动,水位波动模式分别为15 cm-0 cm-15 cm和0 cm-15 cm-0 cm)交叉5种定植模式(试验容器内分别为入侵种单株、本土种单株、入侵种6株、本土种6株以及2物种各3株混种)的试验,研究水位波动对入侵植物和本地近缘种生长繁殖性状及种内种间相互作用的影响.结果表明: 水位波动显著降低了南美蟛蜞菊和蟛蜞菊的总生物量、茎生物量、叶生物量、根生物量、茎长、节点数、叶片数及叶面积,对南美蟛蜞菊和蟛蜞菊种内及种间竞争系数的影响均显著.水位波动改变了南美蟛蜞菊的种内和种间竞争关系,说明入侵植物南美蟛蜞菊对水位波动更为敏感,对环境改变表现出更强的适应性. 相似文献
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紫茎泽兰（Eupatorium adenophorum）入侵喀斯特生态系统导致群落多样性和稳定性降低是该区域面临的重要生态问题,丛枝菌根（Arbuscular mycorrhizae,AM）通过根系外延菌丝互联不同物种个体影响植物养分竞争,但如何调控入侵种与乡土种地上地下资源竞争分配尚不清楚。以入侵种紫茎泽兰和乡土种黄花蒿（Artemisia annua）为研究对象,使用由1个竞争室和2个种植室所组成的微生态系装置。针对两物种对竞争室养分资源利用,采用20 μm和0.45 μm尼龙网设置共同竞争（CC）、单一利用（SU）和对照（CK）处理,并对上述处理进行AM真菌接种（M+）与不接种（M-）,分析不同处理下紫茎泽兰与黄花蒿地下地上生物量及氮磷养分分配。结果表明：就地上部分而言,比较M+与M-,三种竞争方式的紫茎泽兰磷吸收量均显著表现为M+ > M-,但黄花蒿在M+与M-间无显著差异;比较3种竞争方式,M+下紫茎泽兰氮吸收量和黄花蒿生物量及氮磷吸收量表现为SU>CK,黄花蒿地上生物量、氮磷吸收量则表现为CCSU;M+下CC处理紫茎泽兰地上氮吸收量显著高于黄花蒿;M-下黄花蒿氮磷吸收量显著表现为CC和SU>CK,但紫茎泽兰在CC、SU和CK间无显著差异。就地下部分而言,三种竞争方式的紫茎泽兰地下生物量、氮磷吸收量显著表现为M+ > M-,但黄花蒿在M+与M-间无显著差异;比较三种竞争方式,M+下紫茎泽兰氮吸收量在CC与SU间无显著差异,但SU>CK;比较植物间,M+条件下,CC和SU处理的紫茎泽兰氮磷吸收量均显著高于黄花蒿,而M-条件下紫茎泽兰与黄花蒿生物量和氮磷吸收量在三种竞争方式间均无显著差异。研究表明,AM真菌通过菌根网络调控入侵种和乡土种的竞争能力,影响公用土壤养分资源在植株地上地下的资源分配并提高入侵植物从菌根共生体中获得收益促进其入侵。 相似文献
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Geetha Ramaswami Monica Kaushik Soumya Prasad Raman Sukumar David Westcott 《Biotropica》2016,48(5):638-644
In the past century, our understanding of the processes driving plant invasion and its consequences for natural and anthropogenic systems has increased considerably. However, the management of invasive plants remains a challenge despite ever more resources being allocated to their removal. Often invasive plants targeted for ‘eradication’ are well‐established, have multiple modes of reproduction, long‐term seed banks, and strong associations with native and non‐native mutualists that ensure dispersal and facilitate spread. The pantropical weed, Lantana camara (Lantana), is one of the most invasive woody plants globally. We illustrate that, for Lantana, eradication is an unrealistic management goal given the short‐term removal approaches, irrespective of the effectiveness of removal methods. We assessed the role of dispersal by avian frugivores in the recolonization of managed areas by Lantana in the seasonally dry, tropical forests of northern and southern India. We estimated the distribution of Lantana, its dispersal potential and the proximity between managed areas and source populations. We found that Lantana was dispersed by many generalist frugivorous birds and that most managed areas were well within the median dispersal distance from source plants facilitating rapid recolonization of managed areas. We conclude that given the difficulty of eradicating long‐established invasive plants, management practices should entail long‐term monitoring and control in priority areas for as long as Lantana occurs in the landscape. 相似文献
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Understanding the impacts of invasive species requires placing invasion within a full community context. Plant invaders are often considered in the context of herbivores that may drive invasion by avoiding invaders while consuming natives (enemy escape), or inhibit invasion by consuming invaders (biotic resistance). However, predators that attack those herbivores are rarely considered as major players in invasion. Invasive plants often promote predators, generally by providing improved habitat. Here, we show that predator‐promoting invaders may initiate a negative feedback loop that inhibits invasion. By enabling top‐down control of herbivores, predator‐promoting invaders lose any advantage gained through enemy escape, indirectly favoring natives. In cases where palatable invaders encounter biotic resistance, predator promotion may allow an invader to persist, but not dominate. Overall, results indicate that placing invaders in a full community context may reveal reduced impacts of invaders compared to expectations based on simple plant–plant or plant–herbivore subsystems. 相似文献
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Phragmites or Common Reed (Phragmites australis) is a tall rhizomatous cosmopolitan grass. While native to Australia, it can be invasive in wetlands, forming dense monocultures and reducing their ecological integrity. We assessed the potential for the cutting of Phragmites reeds prior to planting to promote the establishment of indigenous shrubs that might ultimately outcompete Phragmites. We established ten 5 m × 5 m quadrats in an area dominated by Phragmites, brush‐cut the reeds to ground level in five of them and left five uncut as controls. Within each quadrat, we planted 20 plants (~40 cm tall) of each of five indigenous shrub species, unguarded (4 plants/m2). We surveyed the plants one month after planting and annually for the following four years for survival, height and browsing damage. Browsing damage to plants was common (>50%) and unaffected by cutting. After four years, overall plant survival rates were ~25% and mean plant heights for the five shrub species ranged between 120 and 174 cm. Cutting of Phragmites had no positive effect on plant survival or height. In fact, two Melaleuca species grew taller in the uncut quadrats. Cutting of Phragmites reed beds prior to planting is unlikely to promote the establishment of woody plantings. However, planting within established Phragmites with or without prior brush‐cutting is worthy of further trialling as a potential tool for reinstating native diversity at Phragmites‐dominated sites. 相似文献
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