bluuebunny/crossref_metadata_2025_split huggingface dataset:
Symbolic dynamics for identifying similarity between rhythms of ecological time series
Authors: Cazelles Bernard 
Published: August 2004

AbstractExplaining the associations between animal populations or between population and environmental signals is an important challenge. The time series that quantify animal populations are often complex, nonlinear, noisy and non‐stationary. These characteristics may make it inappropriate to use traditional techniques when analysing these time series and their mutual dependencies. Here I propose to use symbolic dynamics and techniques from Information Theory to evaluate the degree of dynamic cohesion between time series fluctuations. The main idea is to check whether two (or more) signals tend to oscillate simultaneously, rising and falling together with the same rhythm. Based on synthetic and real time series, I demonstrate that this method is robust to the presence of noise and to the short length of the analysed time series and gives relevant information about the weak relationships between different series. Furthermore, this method appears as simple as classical cross‐correlation and outperforms it in the analysed examples.
Allee effects, mating systems and the extinction risk in populations with two sexes
Authors: Bessa‐Gomes Carmen , Legendre Stéphane , Clobert Jean 
Published: August 2004

AbstractThe Allee effect is one of the population consequences of sexual reproduction that has received increased attention in recent years. Due to its impact on small population dynamics, it is commonly accepted that Allee effects should render populations more extinction prone. In particular, monogamous species are considered more susceptible to the Allee effect and hence, more extinction prone, than polygamous species. Although this hypothesis has received theoretical support, there is little empirical evidence. In this study, we investigate (1) how variation in tertiary sex ratio affects the presence and intensity of the Allee effect induced by mating system, as well as (2) how this effect contributes to extinction risk. In contrast with previous predictions, we show that all mating systems are likely to experience a strong Allee effect when the operational sex ratio (OSR) is balanced. This strong Allee effect does not imply being exceptionally extinction prone because it is associated with an OSR that result in a relatively small extinction risk. As a consequence, the impact of Allee effects on overall extinction risk is buffered. Moreover, the OSR of natural populations appears to be often male biased, thus making it unlikely that they will suffer from an Allee effect induced by mating system.
Generalist and specialist lepidopteran larvae elicit different transcriptional responses in Nicotiana attenuata, which correlate with larval FAC profiles
Authors: Voelckel Claudia , Baldwin Ian T. 
Published: August 2004

AbstractUnlike generalist herbivores, specialists are believed to share a history of evolutionary interactions with their host plants. We determine whether a specialist lepidopteran species alters plant metabolism differently from two generalist species despite similarities in feeding mode and larval elicitors. With a cDNA microarray enriched in defence‐related genes, we compared the transcriptional responses elicited in the native tobacco Nicotiana attenuata by the oligophagous larvae of Manduca sexta and the polyphagous larvae of Heliothis virescens and Spodoptera exigua, which are all members of N. attenuata's natural herbivore community. We found the differences in plant responses to be correlated with the profile of larval elicitors [fatty acid–amino acid conjugates (FAC)] and discuss how variation in FAC composition may shape the interaction between generalist or specialist lepidopteran larvae and plants.
Biodiversity response to climate change in a warm deep sea
Authors: Danovaro Roberto , Dell'Anno Antonio , Pusceddu Antonio 
Published: August 2004

AbstractClimate changes are expected to induce significant modifications in biodiversity on the global scale, but little is known as to how biodiversity has been affected by recent changes in the deep sea. We have used nematodes to investigate the response of deep‐sea biodiversity to an extensive climate anomaly that modified the physico‐chemical characteristics of the deep waters of the Eastern Mediterranean. Using a decadal data set (from 1989 to 1998), we provide evidence that deep‐sea nematode diversity can be strongly and rapidly affected by temperature shifts. The abrupt decrease in temperature (of about 0.4 °C) and modified physico‐chemical conditions that occurred between 1992 and 1994 caused a significant decrease in nematode abundance and a significant increase in diversity. This temperature decrease also resulted in decreased functional diversity and species evenness, and in an increase in the similarity to colder deep‐Atlantic fauna. When the temperature recovered (after 1994–1995), the biodiversity only partially returned to previous values. We conclude that deep‐sea fauna is highly vulnerable to environmental alteration, and that deep‐sea biodiversity is also significantly affected by very small temperature changes. The results presented here provide new elements towards a better understanding of the potential large‐scale consequences of climate change.
Invasion impacts local species turnover in a successional system
Authors: Yurkonis Kathryn A. , Meiners Scott J. 
Published: August 2004

AbstractExotic plant invasions are often associated with declines in diversity within invaded communities. However, few studies have examined the local community dynamics underlying these impacts. Changes in species richness associated with plant invasions must occur through local changes in extinction and/or colonization rates within the community. We used long‐term, permanent plot data to evaluate the impacts of the exotic vine Lonicera japonica. Over time, species richness declined with increasing L. japonica cover. L. japonica reduced local colonization rates but had no effect on extinction rates. Furthermore, we detected significant reductions in the immigration of individual species as invasion severity increased, showing that some species are more susceptible to invasion than others. These findings suggest that declines in species richness associated with L. japonica invasion resulted from effects on local colonization rates only and not through the competitive displacement of established species.
Effects of fine grain environmental variability on morphological plasticity
Authors: Miner Benjamin G. , Vonesh James R. 
Published: August 2004

AbstractVirtually all studies investigating morphological plasticity have focused on how organisms change in response to treatments that are constant throughout the experiment but which have different means. In this study, we investigated the possibility that organisms can morphologically respond to other environmental parameters like the amount of environmental variability or environmental maximum. Sea urchin larvae adjust the length of their feeding structure, a band of cilia, in response to different mean food concentrations. We investigated whether sea urchin larvae are also capable of responding to environmental variability or maxima by rearing larvae on four fluctuating diets, where all treatments had the same mean concentration of food. Larvae reared on a low variable diet produced longer larval arms (i.e. a longer ciliary band) than larvae reared on more variable diets. This response is similar to the morphological change that occurs when the mean food concentration is reduced (small mean = long arms), and indicates that organisms can morphologically respond to environmental parameters other than the environmental mean – such as the amount of environmental variability or the environmental maxima. We also quantified the shape of the relationship between larval arm length and fixed food concentrations to determine whether our results might be explained by nonlinearity in this relationship (i.e. Jensen's inequality). The shape of the relationship was inconsistent with a Jensen's inequality explanation. In addition, sea urchin larvae were unable to track fluctuations in food concentrations. This inability to track our imposed environmental fluctuations indicates that there was a time delay greater than 2 days in the response of larvae to changes in food concentrations. Since plutei likely experience fluctuations in food concentrations at least once a day, it is possible that larvae cannot track natural fluctuations in food concentration. We discuss the importance of our results in light of adaptive interpretations of plasticity and predictions of morphological response.
Protein accumulation and distribution in floodplain soils and river foam
Authors: Harner Mary J. , Ramsey Philip W. , Rillig Matthias C. 
Published: August 2004

AbstractMany processes contribute to nutrient transfer from terrestrial to aquatic systems, but in most cases the contribution of particular organisms is unknown. In this study, we explore how a Bradford‐reactive soil protein (BRSP) produced by arbuscular mycorrhizal fungi may provide nutrients to river ecosystems. Along a floodplain in Montana, we extracted BRSP from soils and related the protein concentrations to the age of soil surfaces. We identified BRSP in surface soils, as well as to a depth of 1.4 m, and found that the protein accumulates through time. We also detected BRSP in foam from five rivers in the western United States. Experiments were conducted that demonstrate that the protein may be leached or washed from soils and become a constituent of foam when mixed into turbulent water. We propose that terrestrially derived soil protein may enter rivers via erosion and leaching and serve as a nutrient source for aquatic organisms.
The effect of a pathogen epidemic on the genetic structure and reproductive strategy of the crustacean Daphnia magna
Authors: Mitchell Suzanne E. , Read Andrew F. , Little Tom J. 
Published: August 2004

AbstractHost–parasite coevolution is potentially of great importance in producing and maintaining biological diversity. However, there is a lack of evidence for parasites directly driving genetic change. We examined the impact of an epidemic of the bacterium Pasteuria ramosa on a natural population of the crustacean Daphnia magna through the use of molecular markers (allozymes) and laboratory experiments to determine the susceptibility of hosts collected during and after the epidemic. Some allozyme genotypes were more heavily infected than others in field samples, and the population genetic structure differed during and after the epidemic, consistent with a response to parasite‐mediated selection. Laboratory studies showed no evidence for the evolution of higher resistance, but did reveal an intriguing life‐history pattern: host genotypes that were more susceptible also showed a greater tendency to engage in sex. In light of this, we suggest a model of host–parasite dynamics that incorporates the cycles of sex and parthenogenesis that Daphnia undergo in the field.
Distinctiveness magnifies the impact of biological invaders in aquatic ecosystems
Authors: Ricciardi Anthony , Atkinson Susanna K. 
Published: August 2004

AbstractThere exist few empirical rules for the effects of introduced species, reflecting the context‐dependent nature of biological invasions. A promising approach toward developing generalizations is to explore hypotheses that incorporate characteristics of both the invader and the recipient system. We present the first general test of the hypothesis that an invader's impact is determined by the system's evolutionary experience with similar species. Through a meta‐analysis, we compared the taxonomic distinctiveness of high‐ and low‐impact invaders in several aquatic systems. We find that high‐impact invaders (i.e. those that displace native species) are more likely to belong to genera not already present in the system.
Having the guts to compete: how intestinal plasticity explains costs of inducible defences
Authors: Relyea Rick A. , Auld Josh R. 
Published: August 2004

AbstractPredators commonly induce phenotypic changes that make prey better at surviving predation at the cost of reduced growth. While we have a good understanding of how trait changes affect predation risk, we lack a mechanistic understanding of why predator‐induced phenotypes differ in growth. Using two mesocosm experiments, we combined phenotypic plasticity theory with predictions from optimal digestion theory to demonstrate that intra‐ and interspecific competition induced relatively long guts while predators induced relatively short guts. The longer guts induced by competition appear to be an adaptive response that allows more efficient digestion and more rapid growth whereas the shorter guts induced by predators appear to result from a tradeoff of building larger tails in predator environments at the cost of smaller bodies. By combining these two bodies of theory, we now have a much better understanding of the mechanisms that cause the phenotypic trade‐offs that select for inducible defences.
Stoichiometry and population dynamics
Authors: Andersen Tom , Elser James J. , Hessen Dag O. 
Published: August 2004

AbstractPopulation dynamics theory forms the quantitative core from which most ecologists have developed their intuition about how species interactions, heterogeneity, and biodiversity play out in time. Throughout its development, theoretical population biology has built on variants of the Lotka–Volterra equations and in nearly all cases has taken a single‐currency approach to understanding population change, abstracting populations as aggregations of individuals or biomass. In this review, we explore how depicting organisms as built of more than one thing (for example, C and an important nutrient, such as P) in stoichiometrically explicit models results in qualitatively different predictions about the resulting dynamics. Fundamentally, stoichiometric models incorporate both food quantity and food quality effects in a single framework, allow key feedbacks such as consumer‐driven nutrient recycling to occur, and generally appear to stabilize predator–prey systems while simultaneously producing rich dynamics with alternative domains of attraction and occasionally counterintuitive outcomes, such as coexistence of more than one predator species on a single‐prey item and decreased herbivore performance in response to increased light intensity experienced by the autotrophs. In addition to the theoretical background, we also review recent laboratory and field studies considering stoichiometric effects on autotroph–herbivore systems, emphasizing algae–Daphnia interactions. These studies support the predictions of stoichiometric theory, providing empirical evidence for alternative stable states under stoichiometric constraints, for negative effects of solar radiation on herbivores via stoichiometric food quality, and for diversity‐enhancing effects of poor food quality. Stoichiometric theory has strong potential for both quantitative and qualitative improvements in the predictive power of population ecology, a major priority in light of the multivariate anthropogenic and natural perturbations experienced by populations. However, full development and testing of stoichiometric population dynamics theory will require greater intellectual tolerance and exchange between researchers working in ecosystem and population ecology.
Elevated CO2 and herbivory influence trait integration in Arabidopsis thaliana
Authors: Gabriela Bidart‐Bouzat M. , Portnoy Stephen , DeLucia Evan H. , Paige Ken N. 
Published: August 2004

AbstractWe lack information on how elevated CO2, and its interaction with other factors like herbivory, affect levels and patterns of trait integration in plants. We experimentally tested the hypothesis that elevated CO2 disrupts and restructures functional associations among plant traits, in the selfing annual, Arabidopsis thaliana. We tested for these effects both in the presence and absence of herbivory by larvae of the diamondback moth, Plutella xylostella. Elevated CO2, both alone and combined with moth herbivory, modified integrated trait responses. In addition, integration under different environments was genotype‐specific. These results imply that global changes in CO2 are likely to cause divergent evolutionary outcomes among populations of plants that differ in the initial structure of their quantitative genetic variation.
Increased susceptibility to enemies following introduction in the invasive plant Silene latifolia
Authors: Wolfe Lorne M. , Elzinga Jelmer A. , Biere Arjen 
Published: August 2004

AbstractOne of the influential hypotheses invoked to explain why species become invasive following introduction is that release from natural enemies favours a shift in investment from defence to traits enhancing growth and reproduction. Silene latifolia was introduced from Europe (EU) to North America (NA) c. 200 years ago where it experiences lower damage by natural enemies. A common garden experiment in EU using seeds from 20 EU and 20 NA populations revealed (1) genetically‐based differences in life history between plants from EU and NA; plants from NA have evolved a weedy phenotype that flowers earlier, and has a two‐ to threefold higher reproductive potential; (2) higher susceptibility of NA plants to fungal infection, fruit predation, and aphid infestation. These results suggest that the invasive NA phenotype has evolved at the expense of defensive abilities. Despite this increased susceptibility to enemies, NA populations still outperformed EU populations in this common garden.
Cullen frontal sinus valved glaucoma shunt: preliminary findings in dogs with primary glaucoma
Authors: Cullen Cheryl L. 
Published: August 2004

AbstractPurpose To evaluate the efficacy of a novel, professionally manufactured, frontal sinus valved glaucoma shunt in maintaining normal intraocular pressure (IOP) and vision in dogs with primary glaucoma.Methods Three eyes of three dogs diagnosed with primary glaucoma were included in this prospective clinical study. A Cullen frontal sinus valved glaucoma shunt was implanted into each glaucomatous globe. Dogs were treated postoperatively with topical neomycin/polymyxin B/0.1% dexamethasone and 0.03% flurbiprofen every 6 h tapered over 8–12 weeks, and meloxicam at 0.1 mg/kg orally every 24 h for 7–10 days. IOP, intracameral shunt position and apparent patency, and vision were assessed twice daily for up to 4 (n= 3 eyes) and 10 (n= 2 eyes) days postoperatively, and then at re‐examination periods of up to 36 weeks (n= 1 eye). Postoperative complications were recorded and documented photographically.Results Normal IOP was maintained in all shunted globes (range 10–29 mmHg; mean = 16.7 mmHg at 24 h; IOP = 23 mmHg at 36 weeks) postoperatively for 2 days (3/3 eyes), 8 weeks (2/2 eyes), and 36 weeks (1/1 eye) without additional antiglaucoma therapies. Photopic vision and shunt position and patency were maintained in all shunted globes for all follow‐up periods. Postoperative complications included mild aqueous flare and fibrin (n= 3 eyes for 3–10 days postoperatively); intracameral shunt occlusion with fibrin (n= 1 eye at days 2 and 4); partial anterior chamber tube extrusion (n= 1 eye at day 4), and focal corneal edema (n= 1 eye at 18 weeks). Tissue plasminogen activator injected intracamerally through the silicone tube near the frontal sinus effectively resolved the fibrinous shunt occlusion.Conclusions The Cullen frontal sinus valved glaucoma shunt shows promise for the management of canine primary glaucoma.
Clinical experience with butyl‐2‐cyanoacrylate adhesive in the management of canine and feline corneal disease
Authors: Watté Christine M. , Elks Rebecca , Moore Denise L. , McLellan Gillian J. 
Published: August 2004

AbstractPurpose  To examine and evaluate clinical indications and postoperative outcome in a series of small animal patients in which corneal disease was managed by the application of butyl 2‐cyanoacrylate adhesive.Materials and methods  In this retrospective study all small animal patients were identified that presented to the Royal Veterinary College, University of London over a 2‐year period, in which corneal disease was managed by the application of butyl 2‐cyanoacrylate. Indications for application, complicating factors prior to gluing, glue retention time, postoperative comfort, and extent of subsequent corneal reaction and scarring were noted for each case. Long‐term follow‐up data concerning visual and cosmetic outcome were obtained from owners and referring veterinarians.Results  Thirty‐seven patients (28 dogs and 9 cats), in which 39 eyes were treated, were identified. Indications for corneal gluing in this series included stromal ulceration (26/39 eyes); descemetocele (4/39 eyes); corneal laceration/foreign body (5/39 eyes); lamellar keratectomy (3/39 eyes) and superficial ulceration (1/39 eyes). At least one factor responsible for initiation, persistence or progression of the ulcer was identified in 66.7% of eyes prior to corneal gluing. These included keratomalacia; confirmed bacterial keratitis; corneal edema related to endothelial disease and keratoconjunctivitis sicca. Cyanoacrylate was generally well tolerated by patients with only 8/34 eyes demonstrating transient blepharospasm and increased lacrimation postoperatively. Retention time of cyanoacrylate varied widely from < 1 week to approximately 6 months, but was < 2 months in the majority (89%) of eyes. Exaggerated corneal vascularization was an infrequent postoperative complication, noted in only six canine eyes, and did not appear to be related to initial corneal disease, glue retention time or breed.Conclusions  Butyl 2‐cyanoacrylate offers a convenient, economical and effective alternative to other treatment modalities, such as conjunctival grafts, in the management of corneal defects in canine and feline patients.
The use of semiconductor diode laser for deflation and coagulation of anterior uveal cysts in dogs, cats and horses: a report of 20 cases
Authors: Gemensky‐Metzler Anne J. , Wilkie David A. , Cook Cynthia S. 
Published: August 2004

AbstractObjective To describe semiconductor diode laser use for anterior uveal cyst deflation and coagulation in dogs, horses and cats.Animals studied The presenting clinical signs, surgical technique and postoperative results for four dogs, nine horses and seven cats with anterior uveal cysts treated with diode laser are described. Treated cysts were of sufficient size and/or number to potentially impair vision, damage the corneal endothelium, or increase intraocular pressure (IOP). One dog with free‐floating cysts exhibited ‘fly biting’ behavior. Cysts were suspected of causing shying on the affected side and/or head‐shaking behavior in seven horses. Cysts were free floating within the anterior chamber in dogs, occurred in the corpora nigrum in horses and were attached to the posterior iris surface in cats. In cats, shallowing of the anterior chamber and dyscoria were observed. In all cats prior to cyst deflation, IOP increased after pharmacologic pupil dilation. Cats were more likely than dogs and horses to have bilateral and multiple cysts.Procedure Two dogs and all horses were treated without general anesthesia and two dogs and all cats were treated under general anesthesia. Diode laser was used to perforate, deflate and coagulate the cysts.Results Postoperatively, all eyes were free of discomfort or significant inflammation and minimal or no topical or systemic anti‐inflammatory therapy was required. Abnormal behavior improved or resolved in all cases. In all cats, IOP 24 h after photocoagulation was lower than the postdilation IOP. Cysts did not recur, but new cysts were discovered in several cases.Conclusion Semiconductor diode laser coagulation of anterior uveal cysts is safe, effective and noninvasive.