bluuebunny/crossref_metadata_2025_split huggingface dataset:
ForecastingCameraria ohridellainvasion dynamics in recently invaded countries: from validation to prediction
Authors: GILBERT M. , GUICHARD S. , FREISE J. , GRÉGOIRE J.‐C. , HEITLAND W. , STRAW N. , TILBURY C. , AUGUSTIN S. 
Published: September 2005

SummaryBiological invasions have an anthropogenic origin, and although many species are able to spread on their own within the newly invaded area, long‐distance dispersal events shown to accelerate rates of spread are frequently associated with human activities. In a previous study, the performances of several invasion models of the spread of the horse chestnut leafminerCameraria ohridellain Germany were compared, demonstrating that the best model in qualitative and quantitative terms was a stratified dispersal model taking into account the effect of human population density on the probability of long‐distance dispersal events.Similar data were collected in France over 4 years (2000–2004, 5274 observation points). These data were used to assess the performance of the best‐fit models from Germany using the original parameters and to model the spread of the leafminer in France.The stratified dispersal model accounting for variations in human population density developed in Germany, predicted the invasion of France with a similar level of predictive power as in the area where it was developed. This suggests that an equivalent level of predictability can be expected in a newly invaded country with similar environmental conditions.We applied the model to forecast the future invasion dynamics in the UK from 2005 to 2008, based on the first observations ofCamerariain the country in 2002–2004. Predictions are discussed in the light of different prevailing environmental conditions.Synthesis and application. The model and predictions developed in this study provide one of the few examples of an a priori model of invasion in a newly invaded country, and provide a simple modelling framework that can be used to explore the spread of other invading organisms. In the case ofCameraria, little can be done to prevent or slow its spread but our model, by predicting changes in distribution and rates of spread, provides fore‐warning of where and when damaging pest populations are likely to appear.
Sink or swim? Viability of a black‐tailed godwit population in relation to flooding
Authors: RATCLIFFE NORMAN , SCHMITT SABINE , WHIFFIN MARK 
Published: September 2005

SummaryGodwits of theLimosa l. limosarace have declined throughout northern Europe because of changing agricultural practices. The relict UK population is now mostly confined to two reserves within flood‐defence structures, and numbers have declined at one of these. This study diagnosed the cause of this decline and evaluated options for remedial management.Re‐nesting models showed that productivity varied among sites and years in relation to flooding patterns. Floods caused breeding failure by forcing godwits to nest on nearby arable fields where nest and chick survival rates were low.A population model showed that flood‐dependent variations in productivity were sufficient to explain the contrasting population trends at the two sites.The relative merits of various options for mitigating the effect of floods on godwits were investigated using a combination of hydrological, re‐nesting and population models.Models assuming a closed population resulted in numbers of godwit pairs at one site, the Ouse Washes in eastern England, declining and becoming extirpated within 30 years under current conditions. Some management options improved productivity, population growth and persistence likelihood, but the chances of extirpation were still high and conservation targets would not be met.Models assuming an open population showed that target populations would only be achieved within 30 years if all of the available flood mitigation options were combined. However, habitat creation outside the Ouse Washes resulted in comparable productivity and population growth at a fraction of the cost.Synthesis and applications.Provision of compensatory habitat is likely to be a more parsimonious means of conserving black‐tailed godwits at the Ouse Washes than flood mitigation. However, reliance on the creation of new habitat is a more risky strategy as the godwits may continue to use traditional arable fields in favour of grassland alternatives, and because their productivity on created grassland is unknown.
Forest change on a steep mountain gradient after extended fire exclusion: San Francisco Peaks, Arizona, USA
Authors: COCKE ALLISON E. , FULÉ PETER Z. , CROUSE JOSEPH E. 
Published: September 2005

SummaryMore than a century of forest management, including fire exclusion, livestock grazing and tree harvesting, may have affected forest structure and composition in south‐western USA. Dendroecological techniques were used to reconstruct an 1876 baseline against which modern conditions could be compared. We assessed the magnitude of changes on the San Francisco Peaks in five distinct forest types: ponderosa, mixed conifer, aspen, spruce–fir and bristlecone.We established a systematic grid of 135 plots, each 0·1 ha in size, over a 1117‐m altitudinal band.In the contemporary forest, density was greatest in spruce–fir and least in bristlecone whereas basal area was greatest in spruce–fir and lowest in ponderosa. In 1876, all forest types had significantly lower densities and basal areas.The period since 1876 was associated with increased forest density, a shift in species composition as a result of invasion of shade‐tolerant conifers, and a trend for mesic species to migrate to lower altitudes. Changes were least evident in the highest altitude forests. Climate and human‐caused and natural biotic disturbance factors probably all played a role in forest change, but we argue that the most prominent factor was probably exclusion of the thinning effect of fire, especially on fire‐susceptible mesic species.Synthesis and applications.Mesic species have encroached to lower altitudes and forest density has increased since 1876. These changes have created to conditions opposite to those suitable for warmer, drier future climates that will display increased fire risk, setting the stage for sudden and severe change. Management is complex because of heavy fuel loading, administrative constraints and high public visibility. However, ‘sky island’ landscapes such as the Peaks represent protected ecosystems of great importance in arid regions. Testing of wildland fire use and other management interventions to restore composition and fuel structures more resilient to warmer climate should proceed.
Predicting calyptrate fly populations from the weather, and probable consequences of climate change
Authors: GOULSON DAVE , DERWENT LARA C. , HANLEY MICHAEL E. , DUNN DEREK W. , ABOLINS STEVEN R. 
Published: September 2005

Summary

Calyptrate flies include numerous species that are disease vectors and have a high nuisance value, notably Musca domestica. Populations are often associated with livestock farms and domestic waste disposal facilities such as landfill, where the accumulating organic matter provides suitable breeding conditions for a range of species.
We examined the relationship between fly numbers and weather conditions using a 4‐year data set of weekly fly catches from six sites in southern UK, together with meteorological data. The first 3 years were used to develop predictive models, and these were then used to forecast fly populations in the fourth year. The accuracy of these predictions was assessed by comparison with the actual fly catches for that year. Separate models were developed for M. domestica, Calliphora spp. and all calyptrate flies combined.
Predictions based only on humidity, temperature and rainfall were strongly correlated with observed data (r2 values ranged from 0·52 to 0·84), suggesting that fly population changes are largely driven by the weather rather than by biotic factors. We can forecast fly populations so that control measures need only be deployed when weather conditions are suitable for a fly outbreak, reducing the need for prophylactic insecticide use.
Climate change was simulated using the most recent predictions of future temperature increases. Our models predicted substantial increases in fly populations up to 244% by 2080 compared with current levels, with the greatest increases occurring in the summer months.
Synthesis and applications. Models developed use weather data to predict populations of pestiferous flies such as M. domestica, which may prove valuable in integrated control programmes. These models predict substantial increases in fly populations in the future under likely scenarios of climate change. If this occurs we may expect considerable increases in the incidence of fly‐borne disease.
Predictive value of plant traits to grazing along a climatic gradient in the Mediterranean
Authors: DE BELLO FRANCESCO , LEPŠ JAN , SEBASTIÀ MARIA‐TERESA 
Published: September 2005

Summary

In the face of large‐scale environmental changes, predicting the consequences for species composition from species’ traits can be a major step towards generalizing ecological patterns and management. Few studies, however, have explored the applicability of this tool in relation to different climatic conditions. Here, the changes in species composition along a gradient of sheep‐grazing pressure (high, low, abandonment) were used to test whether a common set of plant functional traits (PFT) would provide consistent predictions of species’ responses to grazing in different biogeographical regions.
Data were collected across an altitudinal and climatic gradient from Mediterranean rangelands to subalpine grasslands in north‐eastern Spain. Species’ responses were calculated using partial constrained ordination to account only for the effect of grazing intensity. Regression trees and general linear models were applied to identify traits that could predict species’ responses.
Results were mostly consistent with the ruderal vs. competitive strategy (sensuGrime), in terms of life cycle, life form and plant height, and their expected responses to repeated disturbance.
However, the predictive capacity of the investigated traits changed with climatic conditions. Traits generally related to grazing did not show a strong repeatability across the climatic gradient. Convergent selection of climatic conditions and grazing indicated that plant features might reflect an adaptation to multiple selective forces. The climatic conditions acted as filters on the pool of PFT available and shifted the relevance of plant traits as potential predictors. Results were not substantially different after applying phylogenetically independent contrasts (PIC).
Synthesis and applications. At a local scale, plant functional traits are useful tools in predicting species’ responses to grazing and, for conservation purposes, identifying species vulnerable to land‐use changes. However, predictions cannot be extrapolated from one climatic region to another. The methodology proposed in this study to detect predicting traits can be applied more generally. Regression trees, in particular, appear to be a useful tool because they account for non‐additive effects and allow visualizations of trait combinations.
Saltmarsh erosion and restoration in south‐east England: squeezing the evidence requires realignment
Authors: WOLTERS MINEKE , BAKKER JAN P. , BERTNESS MARK D. , JEFFERIES ROBERT L. , MÖLLER IRIS 
Published: September 2005

Summary

Saltmarshes in south‐east England have been eroding rapidly since 1960. Recently, Hughes & Paramor (2004) and Morris et al. (2004) have presented contrasting views on the extent to which physical and biological processes might contribute to the erosion. There are three contentious issues: (i) saltmarsh erosion is the result of coastal squeeze, where sea walls prevent a landward migration of a saltmarsh in response to sea level rise; (ii) saltmarsh erosion is linked to bioturbation and herbivory of seedlings by the ragworm Nereis diversicolor; (iii) new saltmarshes will not develop on managed realignment sites where existing sea walls have been removed because of the effects of ragworms.
In this paper, we provide a literature review of physical and biological processes relevant to the above three issues, and discuss the relative importance of these processes at different spatial and temporal scales.
Our synthesis shows that, at a regional scale, the combination of strong winds, high tides and increased wave height appears to be responsible for the increased rate of marsh erosion and creek dissection recorded in the 1970s. There is also some laboratory evidence that bioturbation and herbivory from populations of Nereis can lead to sediment instability and loss of pioneer plant species, such as Salicornia spp. However, the field evidence is more equivocal and has been conducted at small spatial scales.
At a large number of different managed realignment sites there is strong evidence that even if bioturbation and herbivory by Nereis have occurred, overall the effects have been insufficient to restrict plant succession of exposed sediment.
Synthesis and applications. There is an urgent need for long‐term field studies that integrate and quantify physical and biological processes and the related feedbacks at different spatial and temporal scales. Until this is completed, terms such as coastal squeeze will remain contentious and management decisions will invite criticism.
Climate change: the science and the policy
Authors: KING DAVID 
Published: September 2005

SummaryGlobally we face serious challenges from the effects of climate change. The causal link between global warming and increased greenhouse gas emissions is well established. Carbon dioxide levels are at a higher level than at any time in the past 750 000 years at least, and it is too late to stop further warming and consequent impacts on UK and global societies. Here I summarize the latest scientific evidence for anthropogenic global warming and outline strategies for adapting to its impacts and mitigating the effects in the longer term.
Diversity patterns of vascular epiphytes along an elevational gradient in the Andes
Authors: Krömer Thorsten , Kessler Michael , Robbert Gradstein S. , Acebey Amparo 
Published: September 2005

AbstractAim  To document the elevational pattern of epiphyte species richness at the local scale in the tropical Andes with a consistent methodology.Location  The northern Bolivian Andes at 350–4000 m above sea level.Methods  We surveyed epiphytic vascular plant assemblages in humid forests in (a) single trees located in (b) 90 subplots of 400 m2 each located in (c) 14 plots of 1 ha each. The plots were separated by 100–800 m along the elevational gradient.Results  We recorded about 800 epiphyte species in total, with up to 83 species found on a single tree. Species richness peaked at c. 1500 m and declined by c. 65% to 350 m and by c. 99% to 4000 m, while forests on mountain ridges had richness values lowered by c. 30% relative to slope forests at the same elevations. The hump‐shaped richness pattern differed from a null‐model of random species distribution within a bounded domain (the mid‐domain effect) as well as from the pattern of mean annual precipitation by a shift of the diversity peak to lower elevations and by a more pronounced decline of species richness at higher elevations. With the exception of Araceae, which declined almost monotonically, all epiphyte taxa showed hump‐shaped curves, albeit with slightly differing shapes. Orchids and pteridophytes were the most species‐rich epiphytic taxa, but their relative contributions shifted with elevation from a predominance of orchids at low elevations to purely fern‐dominated epiphyte assemblages at 4000 m. Within the pteridophytes, the polygrammoid clade was conspicuously overrepresented in dry or cold environments. Orchids, various small groups (Cyclanthaceae, Ericaceae, Melastomataceae, etc.), and Bromeliaceae (below 1000 m) were mostly restricted to the forest canopy, while Araceae and Pteridophyta were well represented in the forest understorey.Main conclusions  Our study confirms the hump‐shaped elevational pattern of vascular epiphyte richness, but the causes of this are still poorly understood. We hypothesize that the decline of richness at high elevations is a result of low temperatures, but the mechanism involved is unknown. The taxon‐specific patterns suggest that some taxa have a phylogenetically determined propensity for survival under extreme conditions (low temperatures, low humidity, and low light levels in the forest interior). The three spatial sampling scales show some different patterns, highlighting the influence of the sampling methodology.
Nestedness in fragmented landscapes: a case study on birds, arboreal marsupials and lizards
Authors: Fischer Joern , Lindenmayer David B. 
Published: September 2005

AbstractAim  The potential nestedness of assemblages of birds, arboreal marsupials and lizards was examined in a fragmented landscape in south‐eastern Australia. We assessed which ecological processes were related to the presence or absence of nestedness, particularly in relation to previous autoecological studies in the same study area.Location  Data were collected at Buccleuch State Forest, c. 100 km to the west of the Australian Capital Territory in south‐eastern Australia.Methods  Presence/absence matrices were compiled for birds (40 pine sites, 40 continuous forest sites, 43 fragments), arboreal marsupials (41 continuous forest sites, 39 fragments) and lizards (30 sites including all landscape elements) from a range of field surveys conducted since 1995. Nestedness was analysed using a standardized discrepancy measure, and statistical significance was assessed using the RANDNEST null model. For birds, species thought to be extinction‐prone were analysed separately to assess if assemblages comprising extinction‐prone species were more strongly nested than others. Also, sites with a substantial amount of Eucalyptus radiata were analysed separately to assess whether nestedness was stronger if environmental heterogeneity was minimized.Results  The assemblages of lizards and arboreal marsupials were not nested, probably because of qualitative differences between species in response to environmental conditions. The assemblages of birds in fragments and pine sites were significantly nested, but nestedness was substantially stronger in fragments. For birds, nestedness appeared to be related to somewhat predictable extinction sequences, although there were many outliers in the analysis. Nestedness increased when extinction‐prone species were analysed by themselves. Nestedness decreased when environmental heterogeneity was minimized by including only sites dominated by E. radiata.Main conclusions  In a given landscape, different vertebrate assemblages can respond in vastly different ways to fragmentation. Nestedness analyses can provide a useful overview of likely conservation issues in fragmented landscapes, for example by highlighting the possible roles of local extinction and immigration. However, nestedness analyses are a community‐level tool, and should be complemented by more detailed autoecological studies when applied in a conservation context.
Multiple selection pressures generate adherence to Bergmann's rule in a Neotropical migratory songbird
Authors: Jones Jason , Gibb Christine E. , Millard Susanne C. , Barg Jennifer J. , Katharine Girvan M. , Lisa Veit M. , Friesen Vicki L. , Robertson Raleigh J. 
Published: September 2005

AbstractAim  Bergmann's rule, the tendency for body size to be positively correlated with latitude, is widely accepted but the mechanisms behind the patterns are still debated. Bergmann's originally conceived mechanism was based on heat conservation; other proposed mechanisms invoke phylogeny, migration distance and resource seasonality. With the goal of examining these mechanisms, we quantified morphological variation across the breeding range of a Neotropical migratory songbird, the cerulean warbler (Dendroica cerulea).Location  Deciduous forests of eastern North America.Methods  We sampled nine cerulean warbler populations, spanning the species’ breeding range. We captured 156 males using targeted playback and model presentation, and included 127 adult males in our analyses of morphological variation. We used an information‐theoretical approach to identify climatic variables associated with geographical variation in body size.Results  Cerulean warbler body size adheres to Bergmann's rule: individuals in northern populations are larger than those in southern populations. Variation in body size is best explained by variation in dry and wet‐bulb temperature and actual evapotranspiration.Main conclusions  Adherence to Bergmann's rule by the cerulean warbler appears to be linked to thermodynamics (heat conservation in the north, evaporative cooling in the south) and resource seasonality. Multiple selection pressures can interact to generate a single axis of morphological geographical variation, and even subtle fluctuations in climatic variables can exert significant selection pressures. We suggest that the influence of selection pressures on migrants might be enhanced by migratory connectivity, providing further support for the important role played by this phenomenon in the ecology, evolution and population dynamics of migratory songbirds.
Numerical abundance and biodiversity of below‐ground taxocenes along a pH gradient across the Netherlands
Authors: Mulder Christian , Van Wijnen Harm J. , Van Wezel Annemarie P. 
Published: September 2005

AbstractAim Taxocenes are regulated by different kinds of predictors, but can broad‐scale patterns of prokaryotes (bacteria) and eukaryotes (such as fungi and invertebrates) be ascribed to soil acidity? We sought to test for relationships between the numerical abundances of bacteria, microfungi, nematodes and arthropods along a pH gradient.Location 284 agro‐ecosystems on Pleistocene sand across the Netherlands.Methods Generalized Linear Models (GLM) and stepwise regressions were applied, using soil‐ and leaf‐litter organisms sampled from a land‐cover network.Results The major variation in the numerical abundance of the organisms belonging to the investigated taxocenes could be ascribed to soil acidity. Contrary to expectations, the effects of temperature on numerical abundance were significant only for Fungi and Nematoda (P < 0.0001). Geographical co‐ordinates always play a minor role. The often‐suggested close correlation between the numerical abundance of eukaryotes and their local taxonomic diversity applied only to Arthropoda and Fungi (P < 0.00001). Only the number of bacterial DNA bands seemed to reflect the taxa–area relationship (F‐value = 22.45,P < 0.0001).Main conclusions There were strong relationships between the numerical abundances of all the investigated taxocenes and the field‐measured soil acidity (P < 0.0001). The largest effects were detected in the Fungi, which tended to be much more acid‐tolerant than Bacteria. These patterns imply ecological shifts in the detrital soil food web and deserve further investigation.