bluuebunny/crossref_metadata_2025_split huggingface dataset:
Herbivore‐induced plant volatiles provide associational resistance against an ovipositing herbivore
Authors: Zakir Ali , Sadek Medhat M. , Bengtsson Marie , Hansson Bill S. , Witzgall Peter , Anderson Peter 
Published: May 2013

SummaryPlants produce herbivore‐induced plant volatiles (HIPVs) in response to damage by herbivores. AlthoughHIPVs are known to enhance plant resistance by affecting herbivore host plant preferences and by attracting natural enemies, little is known about the role ofHIPVs on the resistance of neighbouring plants and the mechanism behind this associational resistance.This study examined the effect ofHIPVs from herbivore‐damaged host plants (alfalfa (Medicago sativa), clover (Trifolium alexandrinum) and cotton (Gossypium hirsutum)) on oviposition byEgyptian cotton leafworm (Spodoptera littoralis) (Lepidoptera:Noctuidae) on neighbouring, undamaged host plants.There was a significant reduction in oviposition byS. littoralison undamaged plants adjacent to herbivore‐damaged cotton plants under both field and laboratory conditions. The results showed that the associational resistance byHIPVs depends on direct effects on oviposition behaviour inS. littoralis. There were also indications that other mechanisms may be involved.Associational resistance viaHIPVs was not observed for all plant species tested. Emission ofHIPVs from damaged cotton increased the resistance of undamaged cotton and alfalfa plants to oviposition byS. littoralis, butHIPVs from damaged alfalfa and clover neighbours did not provide resistance to undamaged cotton plants.Synthesis. Our results suggest that the presence ofHIPV‐emitting plant neighbours can reduce herbivory on undamaged plants and enhance plant resistance by affecting oviposition behaviour in insect herbivores.
Soil heterogeneity generated by plant–soil feedbacks has implications for species recruitment and coexistence
Authors: Brandt Angela J. , de Kroon Hans , Reynolds Heather L. , Burns Jean H. 
Published: May 2013

Summary

Most studies of soil heterogeneity have focused on underlying abiotic factors such as soil nutrients. However, increasing recognition of plant–soil feedback (PSF) effects on plant growth, combined with the observation that PSFs operate at small spatial scales, suggests that heterogeneity due to PSF could affect plant population and community dynamics. The consequences of PSF‐generated heterogeneity for coexistence depend on heterogeneity's effects on vital rates and how those vital rates influence population‐level recruitment dynamics.

We measured vital rates and recruitment dynamics of three congeneric pairs of introduced perennial plants grown as monocultures in experimental PSF‐generated soil environments. Field soils collected from conspecifics and congeners were alternated in patches or mixed together to produce heterogeneous and homogeneous soils, respectively.

We quantified the effects of PSF‐generated heterogeneity on germination and establishment and determined how these vital rates affected recruitment. We calculated net pairwise interaction coefficients to predict whether PSFs could mediate coexistence between congeners.

Soil heterogeneity altered the relationship of vital rates to recruitment dynamics for some species. For example, Solanum dulcamara recruited later into heterogeneous than homogeneous soils, and germination was a stronger predictor of the timing of recruitment in heterogeneous soil, while mortality was a stronger predictor in homogeneous soil. Contrasts between soils of different origin suggest that mixing soils had non‐additive effects on vital rates (e.g. Rumex crispus mortality was higher in homogeneous than in conspecific or congener soil). Interaction coefficients predicted that PSFs in heterogeneous soils might mediate stable coexistence only of Rumex congeners.

Synthesis. Heterogeneity generated by PSFs had species‐specific effects on vital rates, with consequences for recruitment dynamics. Mixing soils of different origin often resulted in non‐additive effects, which may indicate an interaction between soil abiotic and/or biotic properties and could predict non‐additive responses to soil disturbance. Finally, quantifying the reciprocal effects of PSFs on congeners suggests that PSF‐generated heterogeneity may promote coexistence of certain species, which was not evident from individual PSF responses. Future studies should determine whether such mechanisms might operate for more distantly related species.
Above‐ and below‐ground herbivory effects on below‐ground plant–fungus interactions and plant–soil feedback responses
Authors: Martijn Bezemer T. , van der Putten Wim H. , Martens Henk , van de Voorde Tess F. J. , Mulder Patrick P. J. , Kostenko Olga 
Published: May 2013

Summary

Feeding by insect herbivores can affect plant growth and the concentration of defense compounds in plant tissues. Since plants provide resources for soil organisms, herbivory can also influence the composition of the soil community via its effects on the plant. Soil organisms, in turn, are important for plant growth. We tested whether insect herbivores, via their effects on the soil microbial community, can influence plant‐soil feedbacks.

We first examined the effects of above‐ground (AG) and below‐ground (B) insect herbivory on the composition of pyrrolizidine alkaloids (PAs) in roots and on soil fungi in roots and rhizosphere soil of ragwort (Jacobaea vulgaris). The composition of fungal communities in roots and rhizosphere soil was affected by both AG and BG herbivory, but fungal composition also differed considerably between roots and rhizosphere soil. The composition of PAs in roots was affected only by BG herbivory.

Thirteen different fungal species were detected in roots and rhizosphere soil. The presence of the potentially pathogenic fungus Fusarium oxysporum decreased and that of Phoma exigua increased in presence of BG herbivory, but only in soil samples.

We then grew new plants in the soils conditioned by plants exposed to the herbivore treatments and in unconditioned soil. A subset of the new plants was exposed to foliar insect herbivory. Plant‐soil feedback was strongly negative, but the feedback effect was least negative in soil conditioned by plants that had been exposed to BG herbivory. There was a negative direct effect of foliar herbivory on plant biomass during the feedback phase, but this effect was far less strong when the soil was conditioned by plants exposed to AG herbivory. AG herbivory during the conditioning phase also caused a soil feedback effect on the PA concentration in the foliage of ragwort.

Synthesis. Our results illustrate how insect herbivory can affect interactions between plants and soil organisms, and via these effects how herbivory can alter the performance of late‐growing plants. Plant‐soil feedback is emerging as an important theme in ecology and these results highlight that plant‐soil feedback should be considered from a multitrophic AG and BG perspective.
Biotic plant–soil feedbacks across temporal scales
Authors: Kardol Paul , De Deyn Gerlinde B. , Laliberté Etienne , Mariotte Pierre , Hawkes Christine V. 
Published: May 2013

Summary

Plant effects on soil biota can result in feedbacks affecting plant performance, with consequences for plant community and ecosystem dynamics on short and long time‐scales. In addition, the strength and direction of plant–soil feedbacks depend on temporal shifts in abiotic environmental conditions.

We synthesize current knowledge on temporal aspects of plant–soil feedbacks and present new ideas to better understand and predict the effects of plant–soil feedbacks on community and ecosystem properties across temporal scales.

Explaining short‐term temporal feedback dynamics requires us to better understand mechanistic linkages between plants, soil organisms and locally available resources. On the other hand, we need to refine our understanding of the context‐dependency of plant–soil feedbacks, as the strength and direction of feedback interactions are influenced by ‘external’ temporal ecosystem dynamics, such as variation in soil resource availability after disturbance or during succession.

Synthesis. Based on our synthesis of temporal aspects of plant–soil feedbacks, we suggest three main avenues for future research: (i) how plant–soil feedbacks changes with ontogeny, (ii) how plant and soil organism traits drive temporal variation in plant–soil feedbacks and (iii) how environmental changes across temporal scales alter the strength and direction of plant–soil feedbacks.
Multi‐millennial fire frequency and tree abundance differ between xeric and mesic boreal forests in centralCanada
Authors: Senici Dominic , Lucas Aurore , Chen Han Y. H. , Bergeron Yves , Larouche Alayn , Brossier Benoit , Blarquez Olivier , Ali Adam A. 
Published: May 2013

SummaryMacroscopic sedimentary charcoal and plant macroremains from two lakes, 50 km apart, in north‐westernOntario,Canada, were analysed to investigate fire frequency and tree abundance in the central boreal forest. These records were used to examine the controls over the long‐term fire regime, and vegetative dynamics associated with fire return intervals (FRIs).There were 52 fire events atLakeBen (surrounded by a xeric landscape) between 10 174 calibrated years before present (cal. yearbp) and the present with an averageFRIof 186 years with values oscillating between 40 and 820 years. Forty‐three fire events were recorded atLakeSmall (surrounded by a mesic landscape) between 9972 cal. yearbpand the present with an averageFRIof 229 years and a range of 60–660 years.FRIs atLakeSmall decreased significantly afterc. 4500 cal. yearbp, whereas atLakeBenFRIs remained similar throughout theHolocene. DifferentFRIdistributions and independence in the occurrence of fire events were detected between 10 000 and 4500 cal. yearbpfor the two sites. Between 4500 cal. yearbpand the present, similarFRIs were observed, but fires continued to occur independently.LongerFRIs resulted in declining abundance ofLarix laricinain both landscapes. LongerFRIs resulted in a decline in the abundance ofPicea marianain the xeric landscape, but a marginal increase in the mesic landscape. Abundances ofPinus banksiana,Pinus strobusandBetula papyriferawere unrelated toFRI, underlying that these species maintain their local abundance irrespective of fire frequency.Synthesis. Our results show contrasting fire regime dynamics between a xeric and mesic landscape in central boreal forests,Canada. These results highlight the influence of local factors as important drivers of fire frequency at centennial to millennial scales. Local site factors, especially soil moisture, need to be incorporated into predictive models of vegetation response to climate change.
Chasing a moving target: projecting climate change‐induced shifts in non‐equilibrial tree species distributions
Authors: García‐Valdés Raúl , Zavala Miguel A. , Araújo Miguel B. , Purves Drew W. 
Published: May 2013

Summary

The geographic distributions of plant species show marked correlations with the current climate, suggesting that they are likely to shift if climate changes. However, before projecting any such shifts, it is important to establish whether distributions are at equilibrium with the current climate. If they are not, distributional shifts could occur even without climate change, making it difficult to tease apart climate‐induced shifts from shifts occurring naturally without climate change.

We forecast the geographical distributions of the 10 most common trees occurring in the Iberian Peninsula using a new method that relaxes the species–climate equilibrium assumption implicit in most species distributions models. For each species, we developed a spatially explicit patch occupancy model (SPOM) with climate‐dependent extinction rates and with colonization rates that depend on both climate and local seed dispersal. Bayesian methods were used to estimate the colonization, extinction and seed dispersal functions against observed colonization and extinction events recorded in repeat surveys of 46 596 forest plots in the Spanish Forest Inventories (1986–96 and 1997–2007). We then simulated distributional changes between the years 2000–2100.

Without climate change, 9 of the 10 species substantially increased in regional frequency. These increases occurred primarily within current ranges, although some species also expanded across their range edges. With climate change, one temperate conifer species and two sub‐Mediterranean species would reduce their frequency of occurrence across the studied region, whereas temperate broad‐leaved species were unaffected and Mediterranean species were either unaffected or increased their frequency of occurrence.

Synthesis. The analysis suggests that these species are substantially out of equilibrium, such that abundances and ranges would increase without climate change. Climate change may increase, decrease, stabilize or shift distributions, in a way that can only be understood by comparing predictions against baseline scenarios that account for these non‐equilibrium range dynamics.
Patterns and drivers of β‐diversity and similarity of Lobaria pulmonaria communities in Italian forests
Authors: Nascimbene Juri , Benesperi Renato , Brunialti Giorgio , Catalano Immacolata , Vedove Marilena D. , Grillo Maria , Isocrono Deborah , Matteucci Enrica , Potenza Giovanna , Puntillo Domenico , Puntillo Michele , Ravera Sonia , Rizzi Guido , Giordani Paolo 
Published: May 2013

Summary

We attempted to elucidate the roles of β‐diversity components and similarity in shaping Lobaria pulmonaria lichen communities in Italian forests to provide scientific tools for improving their long‐term conservation.

A total of 20 sites were selected by stratified random sampling, including five chestnut forests, seven beech–silver fir forests and eight oak forests distributed across 10 administrative regions of Italy. Site selection was based on a national data base including all the available records of L. pulmonaria in Italy. In each forest, four plots were randomly placed, and in each plot, 5–6 trees were randomly selected for lichen sampling. For each forest and plot, meaningful predictors of lichen patterns were quantified. In particular, factors indicative of both geographic conditions and forests structure were considered. The SDR simplex approach was used to estimate the relative importance of similarity (S), relative species replacement (R) and relative richness difference (D) to β‐diversity and similarity, while a hierarchical partitioning (HP) method was used to evaluate the relative importance of environmental predictors in explaining their patterns.

A total of 201 lichens and three nonlichenized fungi were found, including 51 species of conservation concern. The components of β‐diversity and similarity contributed to shaping L. pulmonaria communities at both forest and plot scales across Italy, resulting in nearly random compositions, that is, the species set on each tree was a random sample from the available species pool. Species replacement and similarity were generally associated with forest structure predictors, while richness difference was mainly associated with geographic predictors. The implication of this is that the long‐term conservation of L. pulmonaria communities could be promoted by maintaining scattered nodes and appropriate habitat traits, especially in large forested landscapes where species turnover is higher.

Synthesis. In this work, we used a new approach for analysing a countrywide data set improving the ecological understanding of the dynamics regulating epiphytic communities. In particular, this study improves the understanding of the contribution of different components of diversity across two spatial scales and evaluates the relative importance of environmental predictors in explaining variation of each diversity component.
The ancient forests of La Gomera, Canary Islands, and their sensitivity to environmental change
Authors: Nogué Sandra , de Nascimento Lea , Fernández‐Palacios José María , Whittaker Robert J. , Willis Kathy J. 
Published: May 2013

Summary
Garajonay National Park in La Gomera (Canary Islands) contains one of the largest remnant areas of a forest formation once widespread throughout Europe and North Africa. Here, we aim to address the long‐term dynamics (the last 9600 cal. years) of the monteverde forest (laurel forest and Morella‐Erica heath) located close to the summit of the National Park (1487 m a.s.l.) and determine past environmental and human impacts.
We used palaeoecological (fossil pollen, microscopic and macroscopic charcoal) and multivariate ecological techniques to identify compositional change in the monteverde forest in relation to potential climatic and human influences, based on the analysis of a core site at 1250‐m elevation.
The regional mid‐Holocene change towards drier conditions was matched in this system by a fairly rapid shift in representation of key forest elements, with declines in Canarian palm tree (Phoenix canariensis), Canarian willow (Salix canariensis) and certain laurel forest taxa and an increase in representation of the Morella–Erica woody heath.
Charcoal data suggest that humans arrived on the island between about 3000 and 1800 years ago, a period of minimal vegetation change. Levels of burning over the last 800 years are among the lowest of the entire 9600 years.
Synthesis. A rapid climatic‐induced shift of forest taxa occurred 5500 years ago, with a decrease in hygrophilous species in the pollen record. In contrast, we found no evidence of a significant response to human colonization. These findings support the idea that Garajonay National Park is protecting a truly ancient relict, comprising a largely natural rather than cultural legacy.
An improved model to predict the effects of changing biodiversity levels on ecosystem function
Authors: Connolly John , Bell Thomas , Bolger Thomas , Brophy Caroline , Carnus Timothee , Finn John A. , Kirwan Laura , Isbell Forest , Levine Jonathan , Lüscher Andreas , Picasso Valentin , Roscher Christiane , Sebastia Maria Teresa , Suter Matthias , Weigelt Alexandra 
Published: May 2013

SummaryThe development of models of the relationship between biodiversity and ecosystem function (BEF) has advanced rapidly over the last 20 years, incorporating insights gained through extensive experimental work. We proposeGeneralisedDiversity‐Interactions models that include many of the features of existing models and have several novel features.GeneralisedDiversity‐Interactions models characterise the contribution of two species to ecosystem function as being proportional to the product of their relative abundances raised to the power of a coefficient θ.A value of θ < 1 corresponds to a stronger than expected contribution of species' pairs to ecosystem functioning, particularly at low relative abundance of species.Varying the value of θ has profound consequences for community‐level properties ofBEFrelationships, including: (i) saturation properties of theBEFrelationship; (ii) the stability of ecosystem function across communities; (iii) the likelihood of transgressive overyielding.For low values of θ, loss of species can have a much greater impact on ecosystem functioning than loss of community evenness.GeneralisedDiversity‐Interactions models serve to unify the modelling ofBEFrelationships as they include several other current models as special cases.GeneralisedDiversity‐Interactions models were applied to seven data sets and three functions: total biomass (five grassland experiments), community respiration (one bacterial experiment) and nitrate leaching (one earthworm experiment). They described all the nonrandom structure in the data in six experiments, and most of it in the seventh experiment and so fit as well or better than competingBEFmodels for these data. They were significantly better than Diversity‐Interactions models in five experiments.Synthesis. We show thatGeneralizedDiversity‐Interactions models quantitatively integrate several methods that separately address effects of species richness, evenness and composition on ecosystem function. They describe empirical data at least as well as alternative models and improve the ability to quantitatively test among several theoretical and practical hypotheses about the effects of biodiversity levels on ecosystem function. They improve our understanding of important aspects of the relationship between biodiversity (evenness and richness) and ecosystem function (BEF), which include saturation, effects of species loss, the stability of ecosystem function and the incidence of transgressive overyielding.
Strong congruence in tree and fern community turnover in response to soils and climate in central Panama
Authors: Jones Mirkka M. , Ferrier Simon , Condit Richard , Manion Glenn , Aguilar Salomon , Pérez Rolando 
Published: May 2013

Summary

Plant species turnover in central Panamanian forests has been principally attributed to the effects of dispersal limitation and a strong Caribbean to Pacific gradient in rainfall seasonality. Despite marked geological heterogeneity, the role of soil variation has not been rigorously examined.

We modelled the compositional turnover of trees and ferns in the Panama Canal watershed as a function of soil chemistry, climate and geographical separation, using generalized dissimilarity models (GDMs).

Predictability in both plant groups was strong, with 74% of turnover explained in trees and 49% in ferns. Major trends in the two plant groups were strikingly similar. The independent effects of soils, and of climate for trees, were sizeable, but those of geographical distance were minor. In both plant groups, distance and climatic effects on species turnover covaried strongly.

Including floristic dissimilarity of the other taxon as a predictor increased explained deviance to 81% in trees and 59% in ferns. Controlling for differences in plant density among plots reduced deviance explained by climate and distance, while soil effects remained strong. Limiting the analyses to soils of volcanic origin increased deviance explained by climate, soils and distance, but their effects covaried strongly. Independent soil effects on tree turnover were reduced, but their effects on fern turnover remained pronounced.

Dry season length was the most important climatic predictor for both taxa, and P and pH were the most important soil predictors. Particularly, rapid species turnover was associated with the driest end of the seasonality gradient, linked to declining individual densities and species richness, and with the low end of the phosphorus gradient.

Synthesis. While changes in rainfall and seasonality undoubtedly limit plant distributions in this region, soil effects are at least as important, and interactions between the two are sizeable. This is likely to hold elsewhere in the Caribbean region, where mosaics of marine and volcanic soils combined with pronounced rainfall gradients are common. Strong congruence between our focal taxa suggests that our results can be extrapolated to other plant groups, particularly as trees and ferns are distantly related and represent different life‐forms.