共查询到20条相似文献，搜索用时 15 毫秒
1.
Pieter Sanczuk Sanne Govaert Camille Meeussen Karen De Pauw Thomas Vanneste Leen Depauw Xoaquín Moreira Jonas Schoelynck Marthe De Boevre Sarah De Saeger Kurt Bollmann Jrg Brunet Sara A. O. Cousins Jan Plue Martin Diekmann Bente J. Graae Per‐Ola Hedwall Giovanni Iacopetti Jonathan Lenoir Anna Orczewska Quentin Ponette Federico Selvi Fabien Spicher Pieter Vermeir Kim Calders Hans Verbeeck Kris Verheyen Pieter Vangansbeke Pieter De Frenne 《Global Ecology and Biogeography》2021,30(1):205-219
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Invasive herbivores are often managed to limit their negative impact on plant populations, but herbivore density – plant damage relationships are notoriously spatially and temporally variable. Site and species characteristics (both plant and herbivore) must be considered when assessing the potential for herbivore damage, making it difficult to set thresholds for efficient management. Using the invasive brushtail possum Trichosurus vulpecula in New Zealand as a case study, we parameterized a generic model to predict annual probability of browse‐induced mortality of five tree species at 12 sites. We compared predicted and observed tree mortality for each species + site combination to establish herbivore abundance – tree mortality thresholds for each site on a single and combined tree species basis. Model results indicated it is likely that possum browse was the primary cause of all tree mortality at nine of the 12 species‐site combinations, allowing us to estimate site‐specific thresholds below which possum population numbers should be reduced and maintained to keep tree mortality under a predetermined level, for example 0.5% per year. The browse model can be used to set site‐ and species‐specific management action thresholds, and can be adapted easily for other plant or herbivore species. Results for multiple plant or herbivore species at a single site can be combined to create conservative, site‐wide management strategies, and used to: determine which sites will be affected most by changes in herbivore abundance; quantify thresholds for herbivore management; and justify expenditure on herbivore control. 相似文献
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Gema Hernán María J. Ortega Alberto M. Gándara Inés Castejón Jorge Terrados Fiona Tomas 《Global Change Biology》2017,23(11):4530-4543
Increases in seawater temperature are expected to have negative consequences for marine organisms. Beyond individual effects, species‐specific differences in thermal tolerance are predicted to modify species interactions and increase the strength of top‐down effects, particularly in plant–herbivore interactions. Shifts in trophic interactions will be especially important when affecting habitat‐forming species such as seagrasses, as the consequences on their abundance will cascade throughout the food web. Seagrasses are a major component of coastal ecosystems offering important ecosystem services, but are threatened by multiple anthropogenic stressors, including warming. The mechanistic understanding of seagrass responses to warming at multiple scales of organization remains largely unexplored, especially in early‐life stages such as seedlings. Yet, these early‐life stages are critical for seagrass expansion processes and adaptation to climate change. In this study, we determined the effects of a 3 month experimental exposure to present and predicted mean summer SST of the Mediterranean Sea (25°C, 27°C, and 29°C) on the photophysiology, size, and ecology (i.e., plant‐herbivore interactions) of seedlings of the seagrass Posidonia oceanica. Warming resulted in increased mortality, leaf necrosis, and respiration as well as lower carbohydrate reserves in the seed, the main storage organ in seedlings. Aboveground biomass and root growth were also limited with warming, which could hamper seedling establishment success. Furthermore, warming increased the susceptibility to consumption by grazers, likely due to lower leaf fiber content and thickness. Our results indicate that warming will negatively affect seagrass seedlings through multiple direct and indirect pathways: increased stress, reduced establishment potential, lower storage of carbohydrate reserves, and increased susceptibly to consumption. This work provides a significant step forward in understanding the major mechanisms that will drive the capacity of seagrass seedlings to adapt and survive to warming, highlighting the potential additive effects that herbivory will have on ultimately determining seedling success. 相似文献
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Kevin D. Kohl Robert B. Weiss James Cox Colin Dale M. Denise Dearing 《Ecology letters》2014,17(10):1238-1246
The foraging ecology of mammalian herbivores is strongly shaped by plant secondary compounds (PSCs) that defend plants against herbivory. Conventional wisdom holds that gut microbes facilitate the ingestion of toxic plants; however, this notion lacks empirical evidence. We investigated the gut microbiota of desert woodrats (Neotoma lepida), some populations of which specialise on highly toxic creosote bush (Larrea tridentata). Here, we demonstrate that gut microbes are crucial in allowing herbivores to consume toxic plants. Creosote toxins altered the population structure of the gut microbiome to facilitate an increase in abundance of genes that metabolise toxic compounds. In addition, woodrats were unable to consume creosote toxins after the microbiota was disrupted with antibiotics. Last, ingestion of toxins by naïve hosts was increased through microbial transplants from experienced donors. These results demonstrate that microbes can enhance the ability of hosts to consume PSCs and therefore expand the dietary niche breadth of mammalian herbivores. 相似文献
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Most research examining how herbivores and pathogens affect performance of invasive plants focuses on aboveground interactions. Although important, the role of belowground communities remains poorly understood, and the relative impact of aboveground and belowground interactions is still debated. As well, most studies of belowground interactions have been carried out in controlled environments, so little is known about the role of these interactions under natural conditions or how these relationships may change across a plant's range. Using the invasive plant Cirsium arvense, we performed a reciprocal transplant experiment to test the relative impacts of above‐ and belowground interactions at three sites across a 509‐km latitudinal gradient in its invaded range in Ontario, Canada. At each site, C. arvense seedlings were protected with above‐ and/or belowground exclosures in a factorial design. Plant performance (biomass, height, stem thickness, number of leaves, length of longest leaf, maximum rhizome length) was greatest when both above‐ and belowground exclosures were applied and lowest when no exclosures were applied. When only one type of exclosure was applied, biomass generally improved more with belowground exclosures than with aboveground exclosures. Despite site‐to‐site differences in foliar damage, root damage, and mesofaunal populations, belowground interactions generally had a greater negative impact on performance than aboveground herbivory alone. These results stress the importance of including both aboveground enemy interactions and plant–soil interactions in studies of plant community dynamics and invader performance. 相似文献
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G. F. Veen Judith M. Sarneel Lone Ravensbergen Naomi Huig José van Paassen Winnie Rip Elisabeth S. Bakker 《Freshwater Biology》2013,58(9):1794-1803
- The establishment of riparian plants is determined by abiotic conditions and grazing, although it is usually presumed that the former are most important. We tested the impact of aquatic grazers on the survival and growth of establishing riparian plants and whether the impact of grazing interacts with abiotic conditions.
- We conducted an experiment across 10 Dutch wetlands, covering a large range of water depth and nutrient availability. We introduced 1‐year‐old plants of an emergent (common reed, Phragmites australis) and a floating (water soldier, Stratiotes aloides) species in individual enclosures (n = 5 per site) that excluded predominantly waterbirds, which were the most abundant grazers, and on adjacent unprotected plots. Survival and growth were measured during one growing season.
- Grazing reduced growth (as biomass) of Phragmites and Stratiotes by a mean of 25 and 60%, respectively. Grazing decreased survival of Stratiotes, but not of Phragmites. Shallow water, water‐level fluctuations, eutrophic conditions and enough light favoured both growth and survival of Phragmites. Growth of Stratiotes was unaffected by these factors, but they reduced its survival. For both species, grazing effects on biomass were consistent across environmental conditions, but for Phragmites, grazing effects on survival were influenced by abiotic conditions.
- We conclude that aquatic grazers significantly reduce the establishment and growth of macrophytes in the riparian zone over a wide range of environmental conditions.
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Dylan R. Kent Joshua S. Lynn Steven C. Pennings Lara A. Souza Melinda D. Smith Jennifer A. Rudgers 《Ecology and evolution》2020,10(13):6385-6394
Patterns of insect herbivory may follow predictable geographical gradients, with greater herbivory at low latitudes. However, biogeographic studies of insect herbivory often do not account for multiple abiotic factors (e.g., precipitation and soil nutrients) that could underlie gradients. We tested for latitudinal clines in insect herbivory as well as climatic, edaphic, and trait‐based drivers of herbivory. We quantified herbivory on five dominant grass species over 23 sites across the Great Plains, USA. We examined the importance of climate, edaphic factors, and traits as correlates of herbivory. Herbivory increased at low latitudes when all grass species were analyzed together and for two grass species individually, while two other grasses trended in this direction. Higher precipitation was related to more herbivory for two species but less herbivory for a different species, while higher specific root length was related to more herbivory for one species and less herbivory for a different species. Taken together, results highlight that climate and trait‐based correlates of herbivory can be highly contextual and species‐specific. Patterns of insect herbivory on dominant grasses support the hypothesis that herbivory increases toward lower latitudes, though weakly, and indicates that climate change may have species‐specific effects on plant–herbivore interactions. 相似文献
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Volatile organic compounds (VOCs) emitted by plant roots can influence the germination and growth of neighbouring plants. However, little is known about the effects of root VOCs on plant–herbivore interactions of neighbouring plants. The spotted knapweed (Centaurea stoebe) constitutively releases high amounts of sesquiterpenes into the rhizosphere. Here, we examine the impact of C. stoebe root VOCs on the primary and secondary metabolites of sympatric Taraxacum officinale plants and the resulting plant‐mediated effects on a generalist root herbivore, the white grub Melolontha melolontha. We show that exposure of T. officinale to C.stoebe root VOCs does not affect the accumulation of defensive secondary metabolites but modulates carbohydrate and total protein levels in T. officinale roots. Furthermore, VOC exposure increases M. melolontha growth on T. officinale plants. Exposure of T. officinale to a major C. stoebe root VOC, the sesquiterpene (E)‐β‐caryophyllene, partially mimics the effect of the full root VOC blend on M. melolontha growth. Thus, releasing root VOCs can modify plant–herbivore interactions of neighbouring plants. The release of VOCs to increase the susceptibility of other plants may be a form of plant offense. 相似文献
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Kathryn E. Busch Rebecca R. Golden Thomas A. Parham Lee P. Karrh Mark J. Lewandowski Michael D. Naylor 《Restoration Ecology》2010,18(4):490-500
The Chesapeake Bay, like many other temperate estuaries, has exhibited dramatic declines in the abundance of submerged aquatic vegetation (SAV) during the later half of the twentieth century. Because of the functions SAV serve in maintaining a healthy estuarine ecosystem, SAV restoration has become an important component of Chesapeake Bay restoration. Specifically, recent water quality improvements in areas from which populations of Zostera marina (eelgrass) have been extirpated have suggested that Z. marina restoration could succeed. Early restoration efforts involved transplanting Z. marina plants from healthy source beds to restoration locations, but this was labor intensive, time consuming, expensive, and potentially detrimental to donor beds. This multi‐year project investigated new techniques for large‐scale Z. marina seed collection and processing and compared two seed dispersal methods to evaluate cost effectiveness. Tens of millions of mature Z. marina seeds were collected through snorkeling, SCUBA, or with a mechanical harvester. Seed storage conditions and processing techniques were manipulated in order to maximize seed yield. Seeds were dispersed using two methods: spring seed buoys and fall seed broadcasts. Our costs for planting 1 ha of bottom with Z. marina seeds ranged from $6,674 to $165,699 depending on seeding density and dispersal method used. The average cost per Z. marina seed was $0.17. Interannual variations in seed collection yield and seed viability after summer storage had great impact on final costs. Our results suggest that the use of seeds for large‐scale Z. marina restoration offers a competitive advantage to more traditional transplanting methods. 相似文献
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This study assessed whether the abundance of girellids and kyphosids was related to cover of the palatable green algae, Ulva australis and Ulva compressa, on rocky intertidal reefs in Jervis Bay, New South Wales, Australia. No relationship was found between Ulva spp. cover and abundance of Girella tricuspidata, Girella elevata and Kyphosus sydneyanus during a period of relatively low Ulva spp. cover (i.e. February 2011 to March 2011), but during a period of significantly higher Ulva spp. cover (i.e. October 2011 to November 2011) there was a strong correlation between Ulva spp. cover and G. tricuspidata abundance. Spatial analysis indicated that the abundance of G. tricuspidata was consistent across time, suggesting G. tricuspidata were not moving between reefs in response to variation in Ulva spp. cover between periods but rather that large schools of G. tricuspidata resided on reefs that had relatively higher Ulva spp. cover at certain times of the year. 相似文献
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Rebecca R. Golden Kathryn E. Busch Lee P. Karrh Thomas A. Parham Mark J. Lewandowski Michael D. Naylor 《Restoration Ecology》2010,18(4):501-513
In response to systemic losses of submerged aquatic vegetation (SAV) in the Chesapeake Bay (east coast of North America), the U.S. Environmental Protection Agency's (EPA) Chesapeake Bay Program (CBP) and Maryland Department of Natural Resources (MD DNR) have considered SAV restoration a critical component in Bay restoration programs. In 2003, the CBP created the “Strategy to Accelerate the Protection and Restoration of Submerged Aquatic Vegetation in the Chesapeake Bay” in an effort to increase SAV area. As part of this strategy, large‐scale eelgrass (Zostera marina) restoration efforts were initiated in the Patuxent and Potomac Rivers in Maryland. From 2004 to 2007, nearly 4 million Z. marina seeds were dispersed over 10 ha on the Patuxent River and almost 9 million seeds over 16 ha on the Potomac River. Z. marina seedling establishment was consistent throughout the project (<4%); however, restored eelgrass survival was highly dependent on restoration site. Restoration locations on the Patuxent River experienced initial Z. marina seedling germination, but no long‐term plant survival. Restored Z. marina on the Potomac River has persisted and expanded, both vegetatively and sexually, beyond initial seeding areas. Healthy Z. marina beds now cover approximately five acres of the Potomac River bottom for the first time in decades. The differential success of Z. marina restoration efforts in the two rivers is evidence for the necessity of carefully considering site‐specific characteristics when using large‐scale seeding methods to achieve successful SAV restoration. 相似文献
13.
The Enemy Release Hypothesis posits that invasion of novel habitats can be facilitated by the absence of coevolved herbivores. However, a new environment and interactions with unfamiliar herbivores may impose selection on invading plants for traits that reduce their attractiveness to herbivores or for enhanced defenses compared to native host plants, leading to a pattern similar to enemy release but driven by evolutionary change rather than ecological differences. The Shifting Defense Hypothesis posits that plants in novel habitats will shift from specialized defense mechanisms to defense mechanisms effective against generalist herbivores in the new range. We tested these ideas by comparing herbivore preference and performance of native (Eurasia)‐ and invasive (New World)‐range Medicago polymorpha, using a generalist herbivore, the soybean looper, that co‐occurs with M. polymorpha in its New World invaded range. We found that soybean loopers varied in preference and performance depending on host genotype and that overall the herbivore preferred to consume plant genotypes from naïve populations from Eurasia. This potentially suggests that range expansion of M. polymorpha into the New World has led to rapid evolution of a variety of traits that have helped multiple populations become established, including those that may allow invasive populations to resist herbivory. Thus, enemy release in a novel range can occur through rapid evolution by the plant during invasion, as predicted by the Shifting Defense Hypothesis, rather than via historical divergence. 相似文献
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The longstanding biotic interactions hypothesis predicts that herbivore pressure declines with latitude, but the evidence is mixed. To address gaps in previous studies, we measured herbivory and defence in the same system, quantified defence with bioassays, and considered effects of leaf age. We quantified herbivory and defence of young and mature leaves along a continental gradient in eastern North America in the native herb Phytolacca americana L. Herbivory in the field declined with latitude and was strongly correlated with lepidopteran abundance. Laboratory bioassays revealed that leaf palatability was positively correlated with latitude of origin. Young leaves were more damaged than mature leaves at lower latitudes in the field, but less palatable in bioassays. Both defence and palatability displayed non‐linear latitudinal patterns, suggesting potential mechanisms based on biological or climatic thresholds. In sum, observational and experimental studies find patterns consistent with high herbivore pressure and stronger plant defences at lower latitudes. 相似文献
15.
Understanding the functional economics that drives plant investment of resources requires investigating the interface between plant phenotypes and the variation in ecological conditions. While allocation to defence represents a large portion of the carbon budget, this axis is usually neglected in the study of plant economic spectrum. Using a novel geometrical approach, we analysed the co‐variation in a comprehensive set of functional traits related to plant growth strategies, as well as chemical defences against herbivores on all 15 Cardamine species present in the Swiss Alps. By extracting geometrical information of the functional space, we observed clustering of plants into three main syndromes. Those different strategies of growth form and defence were also distributed within distinct elevational bands demonstrating an association between the functional space and the ecological conditions. We conclude that plant strategies converge into clear syndromes that trade off abiotic tolerance, growth and defence within each elevation zone. 相似文献
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Rafael Zas Alejandro Gonzalez‐Voyer Montserrat Vilà Luis Sampedro 《Journal of Biogeography》2015,42(4):684-693
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The use of Zostera marina (eelgrass) seeds for seagrass restoration is increasingly recognized as an alternative to transplanting shoots as losses of seagrass habitat generate interest in large‐scale restoration. We explored new techniques for efficient large‐scale restoration of Z. marina using seeds by addressing the factors limiting seed collection, processing, survival, and distribution. We tested an existing mechanical harvesting system for expanding the scale of seed collections, and developed and evaluated two new experimental systems. A seeding technique using buoys holding reproductive shoots at restoration sites to eliminate seed storage was tested along with new techniques for reducing seed‐processing labor. A series of experiments evaluated storage conditions that maintain viability of seeds during summer storage for fall planting. Finally, a new mechanical seed‐planting technique appropriate for large scales was developed and tested. Mechanical harvesting was an effective approach for collecting seeds, and impacts on donor beds were low. Deploying seed‐bearing shoots in buoys produced fewer seedlings and required more effort than isolating, storing, and hand‐broadcasting seeds in the fall. We show that viable seeds can be separated from grass wrack based on seed fall velocity and that seed survival during storage can be high (92–95% survival over 3 months). Mechanical seed‐planting did not enhance seedling establishment at our sites, but may be a useful tool for evaluating restoration sites. Our work demonstrates the potential for expanding the scale of seed‐based Z. marina restoration but the limiting factor remains the low rate of initial seedling establishment from broadcast seeds. 相似文献
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Indirect interactions driven by livestock and wild herbivores are increasingly recognized as important aspects of community dynamics in savannas and rangelands. Large ungulate herbivores can both directly and indirectly impact the reproductive structures of plants, which in turn can affect the pollinators of those plants. We examined how wild herbivores and cattle each indirectly affect the abundance of a common pollinator butterfly taxon, Colotis spp., at a set of long‐term, large herbivore exclosure plots in a semiarid savanna in central Kenya. We also examined effects of herbivore exclusion on the main food plant of Colotis spp., which was also the most common flowering species in our plots: the shrub Cadaba farinosa. The study was conducted in four types of experimental plots: cattle‐only, wildlife‐only, cattle and wildlife (all large herbivores), and no large herbivores. Across all plots, Colotis spp. abundances were positively correlated with both Cadaba flower numbers (adult food resources) and total Cadaba canopy area (larval food resources). Structural equation modeling (SEM) revealed that floral resources drove the abundance of Colotis butterflies. Excluding browsing wildlife increased the abundances of both Cadaba flowers and Colotis butterflies. However, flower numbers and Colotis spp. abundances were greater in plots with cattle herbivory than in plots that excluded all large herbivores. Our results suggest that wild browsing herbivores can suppress pollinator species whereas well‐managed cattle use may benefit important pollinators and the plants that depend on them. This study documents a novel set of ecological interactions that demonstrate how both conservation and livelihood goals can be met in a working landscape with abundant wildlife and livestock. 相似文献