bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variation of adult survival drives population dynamics in a migrating forest bat
Authors: Schorcht Wigbert , Bontadina Fabio , Schaub Michael 
Published: June 2009

Summary 1.  Variation of survival across time, between sex and ages strongly affect the population dynamics of long‐lived species. Bats are extremely long‐lived, but the variation of their survival probabilities is poorly studied with reliable methods. 2.
We studied annual local survival probabilities of the migratory Leisler’s bats Nyctalus leisleri based on capture–recapture data from 1119 individuals sampled in bat boxes over 20 years in eastern Germany. We assessed variation in survival between sex and age classes, estimated the temporal variance of survival and tested whether survival was affected by weather during hibernation or pregnancy. 3.  Among females, our analyses revealed two groups of individuals present with different roosting occupancy, survival and/or dispersal. Local survival of locally born females increased with age [first year: 0·45 ± 0·04 (SE); later: 0·76 ± 0·04] and the high recapture probabilities indicate regular presence in the roosts. Recapture probabilities and local survival of foreign adult females were significantly lower, indicating less frequent presence in the roosts and stronger dispersal from the study area. 4.  In adult males, locally born and foreign individuals were nearly identical regarding survival and recapture, indicating a more homogenous group. Local survival was very low in the first year (0·04 ± 0·08), most likely caused by strong natal dispersal. It further increased with age (second year: 0·55 ± 0·20, later: 0·69 ± 0·07). 5.  Survival probabilities of all females varied significantly and in parallel across time, suggesting that a common environmental factor was operating which affected all individuals similarly. Spring temperature and winter North Atlantic Oscillation explained maximally 9% each of the variation in first year and adult female survival. In contrast to our expectations, the temporal variance of first‐year survival was lower than that of adult survival. 6.  We found evidence of a complicated social population structure of female Leisler’s bats. Our analyses suggest that their population dynamics are driven to a large amount by variation of survival, in particular by adult survival. The reason for the major temporal variations remains to be identified.
Pulsed resources and climate‐induced variation in the reproductive traits of wild boar under high hunting pressure
Authors: Sabrina Servanty , Jean‐Michel Gaillard , Carole Toïgo , Serge Brandt , Eric Baubet 
Published: June 2009

Summary 1.  Identifying which factors influence age and size at maturity is crucial for a better understanding of the evolution of life‐history strategies. In particular, populations intensively harvested, hunted or fished by humans often respond by displaying earlier age and decreased size at first reproduction. 2.
Among ungulates wild boar (Sus scrofa scrofa L.) exhibit uncommon life‐history traits, such as high fertility and early reproduction, which might increase the demographic impact of varying age at first reproduction. We analysed variation in female reproductive output from a 22‐year long study of an intensively hunted population. We assessed how the breeding probability and the onset of oestrus responded to changes of female body mass at different ages under varying conditions of climate and food availability. 3.  Wild boar females had to reach a threshold body mass (27–33 kg) before breeding for the first time. This threshold mass was relatively low (33–41% of adult body mass) compared to that reported in most other ungulates (about 80%). 4.  Proportions of females breeding peaked when rainfall and temperature were low in spring and high in summer. Climatic conditions might act through the nutritional condition of females. The onset of oestrus varied a lot in relation to resources available at both current and previous years. Between none and up to 90% of females were in oestrus in November depending on the year. 5.  Past and current resources accounted for equivalent amount of observed variations in proportions of females breeding. Thus, wild boar rank at an intermediate position along the capital–income continuum rather than close to the capital end where similar‐sized ungulates rank. 6.  Juvenile females made a major contribution to the yearly reproductive output. Comparisons among wild boar populations facing contrasted hunting pressures indicate that a high demographic contribution of juveniles is a likely consequence of a high hunting pressure rather than a species‐specific life‐history pattern characterizing wild boar.
Density dependence and climate effects in Rocky Mountain elk: an application of regression with instrumental variables for population time series with sampling error
Authors: Creel Scott , Creel Michael 
Published: June 2009

Summary 1.
Sampling error in annual estimates of population size creates two widely recognized problems for the analysis of population growth. First, if sampling error is mistakenly treated as process error, one obtains inflated estimates of the variation in true population trajectories (Staples, Taper & Dennis 2004). Second, treating sampling error as process error is thought to overestimate the importance of density dependence in population growth (Viljugrein et al. 2005; Dennis et al. 2006). 2.
In ecology, state‐space models are used to account for sampling error when estimating the effects of density and other variables on population growth (Staples et al. 2004; Dennis et al. 2006). In econometrics, regression with instrumental variables is a well‐established method that addresses the problem of correlation between regressors and the error term, but requires fewer assumptions than state‐space models (Davidson & MacKinnon 1993; Cameron & Trivedi 2005). 3.
We used instrumental variables to account for sampling error and fit a generalized linear model to 472 annual observations of population size for 35 Elk Management Units in Montana, from 1928 to 2004. We compared this model with state‐space models fit with the likelihood function of Dennis et al. (2006). We discuss the general advantages and disadvantages of each method. Briefly, regression with instrumental variables is valid with fewer distributional assumptions, but state‐space models are more efficient when their distributional assumptions are met. 4.
Both methods found that population growth was negatively related to population density and winter snow accumulation. Summer rainfall and wolf (Canis lupus) presence had much weaker effects on elk (Cervus elaphus) dynamics [though limitation by wolves is strong in some elk populations with well‐established wolf populations (Creel et al. 2007; Creel & Christianson 2008)]. 5.  Coupled with predictions for Montana from global and regional climate models, our results predict a substantial reduction in the limiting effect of snow accumulation on Montana elk populations in the coming decades. If other limiting factors do not operate with greater force, population growth rates would increase substantially.
Population genetics suggests effectiveness of habitat connectivity measures for the European tree frog in Switzerland
Authors: Angelone Sonia , Holderegger Rolf 
Published: June 2009

Summary 1. Governmental authorities in many countries financially support the implementation of habitat connectivity measures to enhance the exchange of individuals among fragmented populations. The evaluation of the effectiveness of such measures is crucial for future management directions and can be accomplished by using genetic methods. 2. We retraced the population history of the European tree frog in two Swiss river valleys (Reuss and Thur), performed comprehensive population sampling to infer the genetic structure at 11 microsatellite markers, and used first‐generation migrant assignment tests to evaluate the contemporary exchange of individuals. 3. Compared with the Thur valley, the Reuss valley has lost almost double the number of breeding sites and exhibited a more pronounced genetic grouping. However, similar numbers of contemporary migrants were detected in both valleys. In the Reuss valley, 81% of the migration events occurred within the identified genetic groups, whereas in the Thur valley migration patterns were diffuse. 4. Our results show that the connectivity measures implemented in the Reuss valley facilitated effective tree frog migration among breeding sites within distances up to 4 km. Nevertheless, the Reuss valley exhibited high genetic differentiation, which reflected the impact of barriers to tree frog movement such as the River Reuss. By contrast in the Thur valley, a larger number of breeding sites have been preserved and high admixture indicated exchange of individuals at distances up to 16 km. 5. Synthesis and applications. We show that genetic methods can substantiate the effectiveness of connectivity measures taken in conservation management at the landscape scale. We urge responsible authorities from both river valleys to continue implementing connectivity measures and to create a dense network of breeding sites, as spatial gaps of 8 km are rarely traversed by tree frogs.
Responses of invertebrate trophic level, feeding guild and body size to the management of improved grassland field margins
Authors: Woodcock Ben A. , Potts Simon G. , Tscheulin Thomas , Pilgrim Emma , Ramsey Alex J. , Harrison‐Cripps Jennifer , Brown Valerie K. , Tallowin Jerry R. 
Published: June 2009

Summary1. Management of lowland mesotrophic grasslands in north‐west Europe often makes use of inorganic fertilizers, high stocking densities and silage‐based forage systems to maximize productivity. The impact of these practices has resulted in a simplification of the plant community combined with wide‐scale declines in the species richness of grassland invertebrates. We aim to identify how field margin management can be used to promote invertebrate diversity across a suite of functionally diverse taxa (beetles, planthoppers, true bugs, butterflies, bumblebees and spiders).2. Using an information theoretic approach we identify the impacts of management (cattle grazing, cutting and inorganic fertilizer) and plant community composition (forb species richness, grass species richness and sward architecture) on invertebrate species richness and body size. As many of these management practices are common to grassland systems throughout the world, understanding invertebrate responses to them is important for the maintenance of biodiversity.3. Sward architecture was identified as the primary factor promoting increased species richness of both predatory and phytophagous trophic levels, as well as being positively correlated with mean body size. In all cases phytophagous invertebrate species richness was positively correlated with measures of plant species richness.4. The direct effects of management practices appear to be comparatively weak, suggesting that their impacts are indirect and mediated though the continuous measures of plant community structure, such as sward architecture or plant species richness.5. Synthesis and applications. By partitioning field margins from the remainder of the field, economically viable intensive grassland management can be combined with extensive management aimed at promoting native biodiversity. The absence of inorganic fertilizer, combined with a reduction in the intensity of both cutting and grazing regimes, promotes floral species richness and sward architectural complexity. By increasing sward architecture the total biomass of invertebrates also increased (byc.60% across the range of sward architectural measures seen in this study), increasing food available for higher trophic levels, such as birds and mammals.
Efficacy of prescribed grazing depends on timing intensity and frequency
Authors: Rinella Matthew J. , Hileman Benjamin J. 
Published: June 2009

Summary 1. Exotic weeds and woody plants have invaded many grasslands, and prescribed grazing is one management technique used to combat these plants. Prescribed grazing entails introducing livestock such as sheep or goats that eat unwanted plants. It sometimes has desirable effects, but inconsistencies among study results discourage widespread use. Detailed studies that manipulate grazing timings, intensities and frequencies may explain inconsistencies among previous studies and identify effective weed control strategies. 2. We studied Euphorbia esula, an invasive forb avoided by cattle but eaten by sheep. We used simulated grazing (clipping) to estimate E. esula and resident plant responses to cattle and sheep grazing protocols. 3. Depending on timing, intensity and frequency, simulated grazing either: (i) did not dramatically affect the invader and/or resident species, (ii) increased the invader and decreased resident species or (iii) decreased the invader and increased resident species. These disparate results illustrate that successful prescribed grazing entails more than simply introducing animals that eat unwanted plants. 4. Our most promising finding was that removing small quantities of invader and resident species’ biomass at early growth stages reduced the invader and increased resident species over time. Defoliating more intensively at later growth stages often gave the opposite response. Forage availability is lowest in spring, so a given landmass can be prescription grazed with fewer animals (or in less time) in spring compared with later in the year. 5. Synthesis and applications. Our study illustrates that responses to prescribed grazing depend heavily on the specifics of the grazing regime. Our results show that some grazing strategies have the potential to exacerbate weed problems, while other strategies help to control the invader and restore desired species. In the case of E. esula, very light prescribed grazing can be beneficial when conducted early in the growing season.
Robust decisions for declaring eradication of invasive species
Authors: Rout Tracy M. , Thompson Colin J. , McCarthy Michael A. 
Published: June 2009

Summary 1.
Invasive species threaten biodiversity, and their eradication is desirable whenever possible. Deciding whether an invasive species has been successfully eradicated is difficult because of imperfect detection. Two previous studies [Regan et al., Ecology Letters, 9 (2006), 759; Rout et al., Journal of Applied Ecology, 46 (2009), 110] have used a decision theory framework to minimize the total expected cost by finding the number of consecutive surveys without detection (absent surveys) after which a species should be declared eradicated. These two studies used different methods to calculate the probability that the invasive species is present when it has not been detected for a number of surveys. However, neither acknowledged uncertainty in this probability, which can lead to suboptimal solutions. 2.   We use info‐gap theory to examine the effect of uncertainty in the probability of presence on decision‐making. Instead of optimizing performance for an assumed system model, info‐gap theory finds the decision among the alternatives considered that is most robust to model uncertainty while meeting a set performance requirement. This is the first application of info‐gap theory to invasive species management. 3.  We find the number of absent surveys after which eradication should be declared to be relatively robust to uncertainty in the probability of presence. This solution depends on the nominal estimate of the probability of presence, the performance requirement and the cost of surveying, but not the cost of falsely declaring eradication. 4.   More generally, to be robust to uncertainty in the probability of presence, managers should conduct at least as many surveys as the number that minimizes the total expected cost. This holds for any nominal model of the probability of presence. 5.
Synthesis and applications. Uncertainty is pervasive in ecology and conservation biology. It is therefore crucial to consider its impact on decision‐making; info‐gap theory provides a way to do this. We find a simple expression for the info‐gap solution, which could be applied by eradication managers to make decisions that are robust to uncertainty in the probability of presence.
Molecular inference of a Late Pleistocene diversification shift inNigellas. lat. (Ranunculaceae) resulting from increased speciation in the Aegean archipelago
Authors: Bittkau Christiane , Comes Hans Peter 
Published: June 2009

AbstractAim To infer the temporal course and geographical mode of speciation in Mediterranean/Southwest AsianNigellas. lat.Location Mediterranean Basin, Aegean archipelago.Methods Phylogenies forNigellaL. andGaridellaL. (= Nigellas. lat.) were obtained from maximum‐likelihood analyses of internal transcribed spacer (ITS) sequences. Diversification through time was analysed by log lineages‐through‐time (LTT) plots and survival analyses. Relative node age estimates were regressed against the degree of sympatry between sister clades to infer the predominant mode of geographical speciation inNigellas. lat.Results The Late Pleistocene radiation of theNigella arvensiscomplex in the Aegean region caused a significant departure from a stochastic speciation/extinction process of diversification during the evolution ofNigellas. lat., a lineage of (at least) Late Miocene origin. Speciation withinNigellas. lat. predominantly took place in allopatry.Main conclusions No significant effect on diversification rate was found regarding the establishment of a Mediterranean‐type climate, or the onset of the Quaternary climatic oscillations. Rather, the accelerated rate of speciation in theN. arvensiscomplex is plausibly related toincreasedopportunities for allopatric speciation afforded by the (palaeo)geographical complexity of the Aegean archipelago combined with Late Pleistocene changes in climate and sea level. The evolution of self‐pollination and associated changes in habitat preference and flowering time further augmented speciation and niche differentiation within the complex, but these changes did not act as the primary promoters of the radiation process.
Floristic changes in the Iberian Peninsula and Balearic Islands (south‐west Europe) during the Cenozoic
Authors: Postigo Mijarra José M. , Barrón Eduardo , Gómez Manzaneque Fernando , Morla Carlos 
Published: June 2009

AbstractAim  The aim of this work was to identify the main changes in the flora and vegetation of the Iberian Peninsula over the Cenozoic Era, to record the disappearance of taxa associated with these changes and to determine the influence of climate and human activity on these events.Location  The Iberian Peninsula and Balearic Islands.Methods  A critical review was made of the palaeobotanical literature with the aims of detecting patterns of floristic change and extracting information on the disappearance of different taxa over the Cenozoic. These data are viewed alongside the most recent data for the climate of this period. A critical analysis is made of the role of Palaeotropical and Arctotertiary taxa in the forest communities of the Iberian Peninsula throughout the Cenozoic.Results  Although the Eocene–Oligocene transition was a time when many taxa disappeared, the most outstanding events occurred between the end of the Oligocene and throughout the Miocene. Substantial floristic changes took place over this period, including the disappearance of 177 Palaeotropical taxa. This was probably related to acute cooling and aridification; no evidence exists that the Messinian Salinity Crisis had any important effect in the Iberian Peninsula. The last great disappearance of Palaeotropical taxa (36 in total) ended in the Middle–Late Piacenzian; Arctotertiary taxa were most affected during the Pleistocene. The Lower–Middle Pleistocene transition, best represented by marine isotopic stages (MIS) 36–34 and 20–18 and characterized by a change in glacial cyclicity, was the time of the last notable disappearance of taxa.Main conclusions  This work provides the first chronogram of extinctions for the Iberian flora, and records the disappearance of 277 taxa during the Cenozoic. A clear relationship was detected between the main climatic events and the latest appearances of the different taxa.
Socio‐cultural aspects of prompting student reflection in Web‐based inquiry learning environments
Authors: Furberg A. 
Published: June 2009

AbstractThis paper reports on a qualitative study of students' engagement with a Web‐based inquiry environment aimed at prompting student reflection in processes of scientific inquiry. In order to demonstrate how prompts become structuring resources for students' scientific inquiry, detailed analyses of students' interaction processes are conducted. The students' written responses to the reflection prompts indicated a widespread use of a ‘copy and paste’ strategy. The analyses of student interaction deepen this finding and show that instead of participating in reflection activities, the students make use of these ‘copy and paste’ strategies in order to come up with ‘correct’ answers to the prompts. Further, the analyses indicate that the students' employment of these strategies can be seen as a response to what can be termed the institutional practices of schooling embedded within the design of the prompts. These findings are discussed and explored in accordance with findings from previous studies on prompting students' reflection in Web‐based inquiry environments. The study demonstrates the value of a socio‐cultural perspective for gaining a deeper understanding of students' engagement with Web‐based learning environments. Such a perspective can give valuable insight into how to (re)design prompts, and how prompts can be productive parts of students' learning.
An investigation of serum concentration of apoM as a potential MODY3 marker using a novel ELISA
Authors: Cervin C. , Axler O. , Holmkvist J. , Almgren P. , Rantala E. , Tuomi T. , Groop L. , Dahlbäck B. , Karlsson E. 
Published: June 2009

Abstract.  Cervin C, Axler O, Holmkvist J, Almgren P, Rantala E, Tuomi T, Groop L, Dahlbäck B, Karlsson E (Lund University, Malmö, Sweden, Steno Diabetes Center, Gentofte, Denmark, University of Helsinki; and Folkhälsan Research Centre, Helsinki, Finland). An investigation of serum concentration of apoM as a potential MODY3 marker using a novel ELISA. J Intern Med 2010; 267: 316–321.Objective.  To investigate the fitness of serum apolipoprotein M (apoM) concentration as a marker for maturity‐onset diabetes of the young 3 (MODY3).Study design and subjects.  This study consisted of two parts. A family study included 71 carriers of the P291fsinsC mutation in hepatocyte nuclear factor‐1α (HNF‐1α) from the Finnish Botnia study, 53 of whom were diabetic, and 75 matched family controls. A second, case–control study included 24 MODY3 patients, 17 healthy MODY3 mutation carriers, 11 MODY1 patients, 18 type 2 diabetes patients and 19 healthy control individuals. Subjects in the case–control study were recruited from the Botnia study or the Clinic of Endocrinology, Malmö University Hospital. Serum apoM levels were measured using a novel ELISA based on two monoclonal apoM antibodies.Results.  In the family study, mean serum apoM was 10% lower in female carriers of the P291fsinsC mutation compared to the family controls (P = 0.0058), a difference which remained significant after adjustment for diabetes status. There was no observed difference between groups for men. In the case–control study, no significant difference in apoM concentration was observed between MODY3 and type 2 diabetes patients, neither before nor after adjustment for total cholesterol.Conclusions.  Female carriers of the P291fsinsC mutation in HNF‐1α displayed slightly lower apoM serum levels. This difference is too small for apoM to be reliably employed as a biomarker for HNF‐1α mutation status.