Modelling potential impacts of climate change on the bioclimatic envelope of species in Britain and Ireland

Aim Climate change has the potential to have significant impacts on the distribution of species and on the composition of habitats. This paper identifies the potential changes in the future distribution of species under the UKCIP98 climate change scenarios, in order that such changes can be taken into account in conservation management. Location The model was applied to Britain and Ireland. Methods A model based on an artificial neural network was used to predict the changing bioclimate envelopes of species in Britain and Ireland. Fifty‐four species representing 15 habitats were modelled. Results The modelled species could be placed into three categories: those losing suitable climate space, those gaining it, and those showing little or no change. When the species were associated with habitats it was found that Arctic–Alpine/montane heath communities were the most sensitive to climate change, followed by pine woodland and beech woodland in southern England. In lowland heath, wet heath, cereal field margins, coastal grazing marsh, drought‐prone acid grassland and calcareous grassland, the species either showed little change or an increase in suitable climate space. The other eight habitats showed a mixed response. Conclusions The species show a variety of responses to climate change and thus their current habitat associations may alter. The uncertain future of some species and habitats is highlighted. Conservation policy and practice will need to be revised in the face of climate change.     

The distributions and effects of nutrients in the sediments of a shallow eutrophic Chinese lake

The temporal and spatial distribution of total nitrogen and total phosphate in the sediments of a shallow eutrophic Chinese lake (Lake Chao), and their relationships with the physical and chemical features of sediments, and their effects on the lake water quality and trophic state, are presented in this paper. The following results were obtained: (1) higher concentration of Tot-N and Tot-P in the sediments occurred in the summer and the autumn seasons; (2) higher annual average Tot-N and Tot-P concentrations were observed in the sediments near the various river mouths and in the western part of the lake; (3) Tot-N and Tot-P concentration in the lake sediments generally increased with increase in lake sediment Eh, pH, and Al₂O₃, and declined with decrease in lake sediment size diameters and SiO₂; and, (4) correlations were observed in both the temporal and spatial distributions between the trophic state, Tot-N and Tot-P concentration in the lake water, and the Tot-N and Tot-P concentration found in the lake sediments.     

Does diet in Celtic Sea fishes reflect prey availability?

Feeding preferences of Celtic Sea fishes were investigated using a database of stomach content records, collected between 1977 and 1994. The diet of cod Gadus morhua , hake Merluccius merluccius , megrim Lepidorhombus whiffiagonis , whiting Merlangius merlangus and saithe Pollachius virens changed markedly as the animals grew larger, and although large predators generally chose larger bodied prey, the variability of prey sizes consumed also increased. Large predators continued to select small, low value, benthic prey ( e.g . Callionymus spp. and Trisopterus spp.) which were easier to catch, rather than larger, more energy lucrative pelagic prey ( e.g . mackerel Scomber scombrus ), even though these pelagic prey‐fishes were nearly always available and were often very abundant. Stock estimates of the International Council for the Exploration of the Sea and U.K. groundfish survey catches were used as indices of prey abundance. Blue‐whiting Micromesistius poutassou and other small pelagic fishes ( Argentina spp. and clupeoids) were identified as being particularly important, and were consumed by some predators more often than would be expected given the abundance of these prey in the environment. There was no evidence for density‐dependent feeding by predators on mackerel and only hake exhibited density‐dependent feeding on horse‐mackerel. Hake, cod and megrim consumed more blue‐whiting when this prey was at higher abundance in the environment. In choosing what prey to consume, predators must balance costs and benefits, considering the quality of prey and the energy expended during search, capture and handling.     

Multifactorial intervention after a fall in older people with cognitive impairment and dementia presenting to the accident and emergency department: randomised controlled trial

ObjectiveTo determine the effectiveness of multifactorial intervention after a fall in older patients with cognitive impairment and dementia attending the accident and emergency department.DesignRandomised controlled trial.Participants274 cognitively impaired older people (aged 65 or over) presenting to the accident and emergency department after a fall: 130 were randomised to assessment and intervention and 144 were randomised to assessment followed by conventional care (control group).SettingTwo accident and emergency departments, Newcastle upon Tyne.ResultsIntention to treat analysis showed no significant difference between intervention and control groups in proportion of patients who fell during 1 year''s follow up (74% (96/130) and 80% (115/144), relative risk ratio 0.92, 95% confidence interval 0.81 to 1.05). No significant differences were found between groups for secondary outcome measures.ConclusionsMultifactorial intervention was not effective in preventing falls in older people with cognitive impairment and dementia presenting to the accident and emergency department after a fall.

What is already known on this topic

Multifactorial intervention prevents falls in cognitively normal older people living in the community and in those who present to the accident and emergency department after a fallFall prevention strategies have not been tested by controlled trials in patients with cognitive impairment and dementia who fall

What this study adds

No benefit was shown from multifactorial assessment and intervention after a fall in patients with cognitive impairment and dementia presenting to the accident and emergency departmentThe intervention was less effective in these patients than in cognitively normal older people     

The influence of exogenous acetaldehyde solution on the vase life of two carnation (Dianthus caryophyllils L.) cultivars in the absence or presence of exogenous ethylene

The effects of acetaldehyde concentration (0, 0.025, 0.05, 0.1, 0.2,0.3, 0.4 or 0.5%) in solution on the vase life and ethylene productionoftwo carnation (Dianthus caryophyllus L.) cultivarscontrasting in vase life (Sandrosa (long lasting) and Yellow Candy (shortlasting)) were studied. In Sandrosa, acetaldehyde solution (0.05%)increased the vase life by 3 days in the absence, or by 2 days in the presence,of exogenous ethylene; the increase in vase life was associated with a delay inthe ethylene climacteric peak. In Yellow Candy, acetaldehyde (0.05%)increased vase life by 3 days, in an ethylene free environment. In the presenceof exogenous ethylene there was no increase in vase life of Yellow Candy.Acetaldehyde failed to inhibit ethylene production in either of the cultivars.It is suggested that acetaldehyde is not involved in the inhibition of ethylenebiosynthesis or sensitivity to ethylene in these two carnation cultivars.     

Sex-specific associations between reproductive output and hematozoan parasites of American kestrels

Parasites have the potential to decrease reproductive output of hosts by competing for nutrients or forcing hosts to invest in immune function. Conversely, reproductive output may affect parasite loads if hosts allocate resources to reproduction such that allocation to immune function is compromised. Both hypotheses implicitly have a temporal component, so we sampled parasites both before and after egg laying to examine the relationship between reproductive output (indexed using a combined measure of clutch size, egg volume, and initiation date) and blood parasite loads of American kestrels (Falco sparverius). Parasite loads measured prior to egg laying had no adverse effects on subsequent reproductive output. Females that previously had large reproductive outputs subsequently had lower parasite intensities than those whose outputs were smaller, suggesting that females were capable of allocating energy to both forming clutches and reducing parasite loads. Because male kestrels provide most of their mate's energetic needs before, during, and after egg laying, mate choice by females may have consequences for their parasite loads. Females choosing high-quality mates may not only have increased reproductive output, but may also obtain sufficient resources from their mates to enable them to reduce their parasite burdens. Males whose mates had large reproductive outputs were more likely to subsequently be parasitized and have more intense infections. For individual males sampled both before and after egg laying, those whose mates had larger reproductive outputs were also more likely to become parasitized, or remain parasitized, between sampling periods. Increased parasite loads of males may be one mechanism by which the costs of reproduction are paid.