bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting locations of moose–vehicle collisions in Sweden
Authors: SEILER ANDREAS 
Published: April 2005

Summary

Animal–vehicle collisions are a serious problem for road planners and biologists concerned with traffic safety, species conservation and animal welfare. In Sweden, vehicle collisions with moose (MVC) are an important safety issue. Police records average approximately 4500 incidents year−1, including 10–15 human fatalities. New mitigation policies require improved knowledge of the factors influencing the spatial distribution of MVC.
Three logistic regression models were developed to predict MVC risks on public roads for use in strategic and project‐related impact assessment. The models were based on remotely sensed landscape data, road and traffic statistics and estimations of moose density, quantified at 2000 accident and 2000 non‐accident control sites in south‐central Sweden. Model predictions were validated on 2600 1‐km road sections in the county of Örebro, which were classified as either accident or non‐accident roads. Model performances were compared using Akaike's information criterion.
Traffic volume, vehicle speed and the occurrence of fences were dominant factors determining MVC risks, identifying 72·7% of all accident sites. Within a given road category, however, the amount of and distance to forest cover, density of intersections between forest edges, private roads and the main accident road, and moose abundance indexed by harvest statistics, significantly distinguished between accident and control sites. In combination, road–traffic and landscape parameters produced an overall concordance in 83·6% of the predicted sites and identified 76·1% of all test road sections correctly.
Synthesis and applications. The risk of moose–vehicle collisions in Sweden can be predicted from remotely sensed landscape data in combination with road traffic data. Prediction models suggest that reduced vehicle speed in combination with road fencing and increased roadside clearance may provide effective tools for road planners in counteracting MVC. However, effective mitigation will depend on integrated management of the surrounding landscape and moose population, as well as increased responsibility of individual drivers. Remedying animal–vehicle collisions must involve road authorities as much as landowners and the public.
Ecological fitness of a multiple herbicide‐resistant Lolium rigidum population: dynamics of seed germination and seedling emergence of resistant and susceptible phenotypes
Authors: VILA‐AIUB M. M. , NEVE P. , STEADMAN K. J. , POWLES S. B. 
Published: April 2005

Summary

Quantification of fitness differences between herbicide‐resistant and herbicide‐susceptible weeds permits better prediction of herbicide resistance, and the design of weed management strategies to exploit those traits that result in reduced ecological performance. Reported here is the first attempt to compare the germination and seedling emergence characteristics of one herbicide‐susceptible and two herbicide‐resistant phenotypes from a single weed population.
A series of experiments was carried out in controlled conditions to study seed germination and emergence in Lolium rigidum phenotypes possessing target‐site and non‐target‐site mechanisms of herbicide resistance. Lines composed of herbicide‐susceptible (S), metabolism‐based (P450) and target site‐based (ACCase) resistant individuals, isolated from a single multiple‐resistant population (SLR31), were used in the comparative experiments.
No major differences in seedling emergence were found among the phenotypes when exposed to an alternating 25/15 °C cycle with a 12‐hourly photoperiod. However, the absence of light associated with soil burial (1–8 cm) markedly inhibited total germination and seedling emergence in the ACCase phenotype compared with the S and P450 phenotypes.
Germination at constant temperatures was also inhibited in seeds of the ACCase phenotype, which showed the highest base temperature (Tb) for germination and required more time to reach 50% emergence (tE50) than the S and P450 phenotypes.
Seedling emergence from deep burial (8 cm) in soil promoted significantly higher fatal germination in the S and P450 phenotypes compared with the ACCase phenotype. Despite fatal germination, the S phenotype produced greater emergence from deep burial than both herbicide‐resistant phenotypes.
Synthesis and applications. This study demonstrates differential germination and emergence responses to light and thermal environments between herbicide‐susceptible phenotypes and phenotypes possessing target‐site (ACCase) and non‐target site (P450) herbicide resistance within a single L. rigidum population. Shallow seed burial (1 cm) by any cultivation tool will potentially inhibit seedling recruitment of the ACCase phenotype in contrast with the S and P450 phenotypes, which require less restricted conditions to germinate and emerge.
Moose harvesting strategies in the presence of wolves
Authors: NILSEN ERLEND B. , PETTERSEN TERJE , GUNDERSEN HEGE , MILNER JOS M. , MYSTERUD ATLE , SOLBERG ERLING J. , ANDREASSEN HARRY P. , STENSETH NILS CHR. 
Published: April 2005

Summary

Large carnivores are currently recolonizing areas where they have been extinct for decades. This poses considerable challenges for wildlife managers, partly because the optimal harvesting strategies of prey populations may be affected. If the carnivores in such areas are under strict management control (as in Scandinavia), the predator will not show a numerical response to changes in prey density. Consequently, the density of prey is mainly determined by the vital rates of the prey population and the predation pressure. In this study we modelled the optimal harvesting strategy for a prey population in which there was no numerical response by the predator.
Our model is an age‐structured deterministic matrix model system. Optimal harvesting strategies are determined, measuring yield either as number of animals harvested or as mass of meat.
First, using a moose population in Hedmark in south‐eastern Norway as a case study, we demonstrate that continuing to harvest at the rates used prior to wolf recolonization will lead to a decline in the moose population.
Secondly, harvesting quotas are specified by age and sex, usually with a high proportion of calves. Although wolves mainly kill juvenile moose (calves and yearlings), the relationship between harvest composition and yield is not affected by predation. Both in the presence and absence of predation, a high proportion of calves in the harvest gives the highest yield measured as the number of animals harvested, whereas a high proportion of adults maximizes the yield measured in terms of meat. Furthermore, a female‐biased sex structure in the population gives a higher yield in both the presence and absence of the predator.
Synthesis and applications. We have shown that managers facing the new challenges presented by recolonizing populations of large predators such as wolves should reduce the size of harvest quotas in order to avoid decreases in prey populations. However, the general relationship between the harvesting strategy and yield maximization is not affected by wolf predation. The harvest yield from cervid populations is often important to local economies, and moose is the single most important game species in Scandinavia. It is therefore important to implement optimal harvesting strategies under these new conditions in order to prevent an unnecessary loss of yield, and success in this task may in turn affect local attitudes towards large carnivores.
An assessment of grassland restoration success using species diversity components
Authors: MARTIN LEANNE M. , MOLONEY KIRK A. , WILSEY BRIAN J. 
Published: April 2005

Summary

We do not know which aspects of community structure and ecosystem processes are restorable for most ecosystems, yet this information is crucial for achieving successful restoration.
We quantified three success criteria for 8–10‐year‐old grassland plantings in large‐scale tallgrass prairie restoration (reconstruction) sites relative to three nearby prairie remnant sites. The restoration sites included management of native ungulates and fire, important regulators of diversity and patchiness in intact grasslands. These have not been incorporated simultaneously into previous studies of restoration success.
We used the additive partitioning model of diversity, where α is neighbourhood (quadrat) scale diversity, β is accumulation of species diversity across neighbourhoods, and γ is total diversity. We decomposed α into richness and evenness to determine if both were equally restored.
The proportion of exotic biomass was similar between the restoration and remnant sites, but the proportion of exotic species and above‐ground net primary productivity remained between two and four times higher in the restoration sites.
Alpha diversity (Simpson's 1/D) and richness (S) values were exceptionally high in remnant sites, and approximately twice those of the restoration sites. Alpha evenness was similar between the restoration and remnant sites.
Distance per se between quadrats was not related to diversity after accumulated quadrat area was taken into account. Therefore, we may be able to use the additive partitioning model of diversity in areas that differ in size, at least at the scale of this study.
Contrary to our original predictions, the proportion of β diversity (1 − D) was approximately twice as high in the restoration sites than in remnant sites, possibly because patches of individual species were larger in the restoration.
Synthesis and applications. We have shown that current restoration methods are unable to restore plant diversity in tallgrass prairie. Grassland restoration will be improved if the number of species that co‐exist can be increased. New, local‐scale restoration techniques are needed to replicate the high levels of diversity observed in tallgrass prairie remnant sites.
Beyond the Mediterranean peninsulas: evidence of central European glacial refugia for a temperate forest mammal species, the bank vole (Clethrionomys glareolus)
Authors: DEFFONTAINE V. , LIBOIS R. , KOTLÍK P. , SOMMER R. , NIEBERDING C. , PARADIS E. , SEARLE J. B. , MICHAUX J. R. 
Published: April 2005

AbstractThis study details the phylogeographic pattern of the bank vole, Clethrionomys glareolus, a European rodent species strongly associated with forest habitat. We used sequences of 1011 base pairs of the mitochondrial DNA cytochrome b gene from 207 bank voles collected in 62 localities spread throughout its distribution area. Our results reveal the presence of three Mediterranean (Spanish, Italian and Balkan) and three continental (western, eastern and ‘Ural’) phylogroups. The endemic Mediterranean phylogroups did not contribute to the postglacial recolonization of much of the Palaearctic range of species. Instead, the major part of this region was apparently recolonized by bank voles that survived in glacial refugia in central Europe. Moreover, our phylogeographic analyses also reveal differentiated populations of bank voles in the Ural mountains and elsewhere, which carry the mitochondrial DNA of another related vole species, the ruddy vole (Clethrionomys rutilus). In conclusion, this study demonstrates a complex phylogeographic history for a forest species in Europe which is sufficiently adaptable that, facing climate change, survives in relict southern and northern habitats. The high level of genetic diversity characterizing vole populations from parts of central Europe also highlights the importance of such regions as a source of intraspecific genetic biodiversity.
An interspecific comparison of foraging range and nest density of four bumblebee (Bombus) species
Authors: KNIGHT M. E. , MARTIN A. P. , BISHOP S. , OSBORNE J. L. , HALE R. J. , SANDERSON R. A. , GOULSON D. 
Published: April 2005

AbstractBumblebees are major pollinators of crops and wildflowers in northern temperate regions. Knowledge of their ecology is vital for the design of effective management and conservation strategies but key aspects remain poorly understood. Here we employed microsatellite markers to estimate and compare foraging range and nest density among four UK species: Bombus terrestris, Bombus pascuorum, Bombus lapidarius, and Bombus pratorum. Workers were sampled along a 1.5‐km linear transect across arable farmland. Eight or nine polymorphic microsatellite markers were then used to identify putative sisters. In accordance with previous studies, minimum estimated maximum foraging range was greatest for B. terrestris (758 m) and least for B. pascuorum (449 m). The estimate for B. lapidarius was similar to B. pascuorum (450 m), while that of B. pratorum was intermediate (674 m). Since the area of forage available to bees increases as the square of foraging range, these differences correspond to a threefold variation in the area used by bumblebee nests of different species. Possible explanations for these differences are discussed. Estimates for nest density at the times of sampling were 29, 68, 117, and 26/km2 for B. terrestris, B. pascuorum, B. lapidarius and B. pratorum, respectively. These data suggest that even among the most common British bumblebee species, significant differences in fundamental aspects of their ecology exist, a finding that should be reflected in management and conservation strategies.
Experimental sexual selection in Chlamydomonas
Authors: BELL G. 
Published: April 2005

AbstractSexual and asexual lines of the unicellular chlorophyte Chlamydomonas reinhardtii were propagated for about 100 sexual cycles and 1000 vegetative cycles in contrasted environments, liquid and solid growth media, in order to generate divergent natural and sexual selection. Sexual lines were transferred by many zygotes or by a single zygote in each sexual generation. By the end of the experiment zygote production was in the order sexual mass‐transfer > sexual single‐zygote > asexual > ancestor. The direct response to sexual selection was large, with zygote production increasing by about two orders of magnitude, mainly because mating had become spontaneous instead of being invoked by nitrogen starvation. Asexual lines became sexually sterilized by the fixation of a single mating type. Sexual selection caused a radical shift in the gender system, with homothallism spreading to high frequency in all sexual lines of this normally heterothallic species. This may have been caused by the transposition of a mating‐type gene to an autosome. No substantial degree of environment‐specific mating evolved, however, and thus no sexual isolation indicative of incipient speciation. It is possible that selection experiments of this kind are unlikely to induce sexual isolation because mating‐type genes evolve in a saltatory fashion.
Hamilton's rule, imprinting and parent–offspring conflict over seed mass in partially selfing plants
Authors: DE JONG T. J. , VAN DIJK H. , KLINKHAMER P. G. L. 
Published: April 2005

AbstractWhen genes in the offspring control the provisioning of the seed, the optimal seed size can be calculated exactly by applying Hamilton's rule. When seed size is a compromise between mother and offspring, we predict that outcrossing plant species produce larger seeds than selfers. This trend was found in the British flora and in a number of well‐studied plant families. The analysis was extended to imprinting, a conditional strategy in which a gene in the offspring takes more resources when derived from the father than from the mother. The conditions for imprinting to be selected were rather restrictive. The analysis is relevant for the current debate about the evolution of imprinting in Arabidopsis thaliana.
Within clutch co‐variation of egg mass and sex in the black‐headed gull
Authors: MÜLLER W. , GROOTHUIS T. G. G. , EISING C. M. , DAAN S. , DIJKSTRA C. 
Published: April 2005

AbstractFemale birds of several species have control over the production of daughters and sons. However, most studies failed to find a relationship between egg size and sex. This is intriguing as adjustment of egg size would constitute a powerful tool for the female to meet different resource demands of the sexes, particularly in size dimorphic species. Our results show that, within clutches of black‐headed gulls (Larus ridibundus) the proportion of males was positively associated with egg mass. This applied for all three laying positions, independently of the absolute egg mass. There was a significant relationship between the distribution of the sexes over the laying sequence and the egg mass change. When egg mass decreased over the sequence, first‐laid eggs were male biased and last‐laid eggs female biased, and vice versa. The potential adaptive value of this allocation strategy is evaluated with regard to male sensitivity to egg quality and competitive differences between the sexes.
Contemporary gene flow and the spatio‐temporal genetic structure of subdivided newt populations (Triturus cristatus,T. marmoratus)
Authors: JEHLE R. , WILSON G. A. , ARNTZEN J. W. , BURKE T. 
Published: April 2005

AbstractGene flow and drift shape the distribution of neutral genetic diversity in metapopulations, but their local rates are difficult to quantify. To identify gene flow between demes as distinct from individual migration, we present a modified Bayesian method to genetically test for descendants between an immigrant and a resident in a nonmigratory life stage. Applied to a metapopulation of pond‐breeding European newts (Triturus cristatus,T. marmoratus) in western France, the evidence for gene flow was usually asymmetric and, for demes of known census size (N), translated into maximally seven reproducing immigrants. Temporal sampling also enabled the joint estimation of the effective demic population size (Ne) and the immigration ratem(including nonreproductive individuals).Neranged between 4.1 and 19.3 individuals,Ne/Nranged between 0.05 and 0.65 and always decreased withN;mwas estimated as 0.19–0.63, and was possibly biased upwards. We discuss how genotypic data can reveal fine‐scale demographic processes with important microevolutionary implications.
A chemical level in the coevolutionary arms race between an ant social parasite and its hosts
Authors: BRANDT M. , HEINZE J. , SCHMITT T. , FOITZIK S. 
Published: April 2005

AbstractHere we investigate the coevolutionary interactions between the slavemaking antProtomognathus americanusand itsTemnothoraxhosts on a chemical level. We show that, although this social parasite is principally well‐adapted to its hosts’ cuticular hydrocarbon profile, there are pronounced differences in the fine‐tuning of this adaptation. Between populations, chemical adaptation varies with host community composition, as the parasite faces a trade‐off when confronted with more than one host species. In addition to adaptation of its own chemical signature, the slavemaker causes a reciprocal adjustment in its slaves’ cuticular profile, the degree of which depends on the slave species. On the host side, successful parasite defence requires efficient enemy recognition, and in behavioural aggression trials, host colonies could indeed discriminate between invading slaves, which commonly accompany slavemakers on raids, and free‐living conspecifics. Furthermore, hosts shifted their acceptance threshold over the seasons, presumably to reduce the costs of defence.
Natural selection and genetic variation for female resistance to harm from males
Authors: LINDER J. E. , RICE W. R. 
Published: April 2005

AbstractThe sexual conflict hypothesis predicts that males evolve traits that exploit the higher parental investment of females, which generates selection for females to counter‐evolve resistance. In Drosophila melanogaster it is now established that males harm females and that there is genetic variation among males for the degree of this harm. Genetic variation among females for resistance to harm from males, and the corresponding strength of selection on this variation, however, have not been quantified previously. Here we carryout a genome‐wide screen for female resistance to harm from males. We estimate that the cost of interactions with males depresses lifetime fecundity of females by 15% (95% CI: 8.2–22.0), that genetic variation for female resistance constitutes 17% of total genetic variation for female adult fitness, and that propensity to remate in response to persistent male courtship is a major factor contributing to genetic variation for female resistance.
Competing dwarf males: sexual selection in an orb‐weaving spider
Authors: FOELLMER M. W. , FAIRBAIRN D. J. 
Published: April 2005

AbstractHypotheses for the adaptive significance of extreme female‐biased sexual size dimorphism (SSD) generally assume that in dimorphic species males rarely interfere with each other. Here we provide the first multivariate examination of sexual selection because of male–male competition over access to females in a species with ‘dwarf’ males, the orb‐weaving spider Argiope aurantia. Male A. aurantia typically try to mate opportunistically during the female's final moult when she is defenceless. We show that, contrary to previous hypotheses, the local operational sex ratio (males per female on the web) is male‐biased most of the season. Both interference and scramble competition occur during opportunistic mating, the former leading to significant selection for large male body size. Male condition and leg length had no effect on mating success independent of size. We discuss these findings in the context of the evolution of extreme female‐biased SSD in this clade.
The evolution of self‐fertilization and inbreeding depression under pollen discounting and pollen limitation
Authors: PORCHER E. , LANDE R. 
Published: April 2005

AbstractWe model the evolution of plant mating systems under the joint effects of pollen discounting and pollen limitation, using a dynamic model of inbreeding depression, allowing for partial purging of recessive lethal mutations by selfing. Stable mixed mating systems occur for a wide range of parameter values with pollen discounting alone. However, when typical levels of pollen limitation are combined with pollen discounting, stable selfing rates are always high but less than 1 (0.9 < s < 1 in most cases); in this situation, complete selfing does not evolve because pollen discounting becomes very large at high selfing rates, so that the automatic advantage of selfing changes to a disadvantage. These results suggest that mixed mating systems with high selfing rates can be maintained by selection, whereas mixed mating systems with low to moderate selfing rates are more likely attributable to unavoidable geitonogamous selfing.