Small forest patches as pollinator habitat: oases in an agricultural desert?

Landscape Ecology - Small forest fragments are often the most abundant type of semi-natural habitat in intensive agricultural landscapes. Wild pollinators can use these forest patches as nesting or...     

The effect of mass-flowering orchards and semi-natural habitat on bumblebee colony performance

Landscape Ecology - Bumblebees are important pollinators for agricultural crops and wild plants. However, agricultural intensification and loss of semi-natural habitat may have adverse effects on...     

Landscape factors and regional differences in recovery rates of herb layer richness in Flanders (Belgium)

The recovery of understory plants in recent forests is critical for evaluating the overall capacity of landscapes to maintain plant biodiversity. Here we used a large data set of vegetation plots from the Flemish Forest Inventory in combination with maps of forest history and soil-based Potential Natural Vegetation to evaluate regional differences in the rate of recovery of understory plant diversity in three regions of Flanders, Belgium. We expressed the degree of recovery in recent forests using the species richness of ancient forests as a reference point, and found strong differences among regions in the average level of recovery. These differences appeared to be due to regional variation in average patch connectivity and age (ultimately stemming from differences in land use history) and – to a lesser extent – environmental conditions. We also found an increase in the proportional representation of vertebrate dispersed species and species with short-distance dispersal with increasing levels of recovery. Our results highlight the potential drivers of inter-regional variation in the process of recovery of plant diversity during restoration, and they emphasize the importance of historical and spatial context in the recovery process.     

Significant effects of temperature on the reproductive output of the forest herb Anemone nemorosa L.

Climate warming is already influencing plant migration in different parts of the world. Numerous models have been developed to forecast future plant distributions. Few studies, however, have investigated the potential effect of warming on the reproductive output of plants. Understorey forest herbs in particular, have received little attention in the debate on climate change impacts.This study focuses on the effect of temperature on sexual reproductive output (number of seeds, seed mass, germination percentage and seedling mass) of Anemone nemorosa L., a model species for slow colonizing herbaceous forest plants. We sampled seeds of A. nemorosa in populations along a 2400 km latitudinal gradient from northern France to northern Sweden during three growing seasons (2005, 2006 and 2008). This study design allowed us to isolate the effects of accumulated temperature (Growing Degree Hours; GDH) from latitude and the local abiotic and biotic environment. Germination and seed sowing trials were performed in incubators, a greenhouse and under field conditions in a forest. Finally, we disentangled correlations between the different reproductive traits of A. nemorosa along the latitudinal gradient.We found a clear positive relationship between accumulated temperature and seed and seedling traits: reproductive output of A. nemorosa improved with increasing GDH along the latitudinal gradient. Seed mass and seedling mass, for instance, increased by 9.7% and 10.4%, respectively, for every 1000 °C h increase in GDH. We also derived strong correlations between several seed and seedling traits both under field conditions and in incubators. Our results indicate that seed mass, incubator-based germination percentage (Germ%_Inc) and the output of germinable seeds (product of number of seeds and Germ%_Inc divided by 100) from plants grown along a latitudinal gradient (i.e. at different temperature regimes) provide valuable proxies to parameterize key population processes in models.We conclude that (1) climate warming may have a pronounced positive impact on sexual reproduction of A. nemorosa and (2) climate models forecasting plant distributions would benefit from including the temperature sensitivity of key seed traits and population processes.     

EuMIXFOR empirical forest mensuration and ring width data from pure and mixed stands of Scots pine (<Emphasis Type="Italic">Pinus sylvestris L.</Emphasis>) and European beech (<Emphasis Type="Italic">Fagus sylvatica L.</Emphasis>) through Europe

Key message

This data set provides unique empirical data from triplets of Scots pine ( Pinus sylvestris L.) and European beech ( Fagus sylvatica L.) across Europe. Dendrometric variables are provided for 32 triplets, 96 plots, 7555 trees and 4695 core samples. These data contribute to our understanding of mixed stand dynamics. Dataset access at   http://dx.doi.org/10.5061/dryad.8v04m . Associated metadata available at https://metadata-afs.nancy.inra.fr/geonetwork/apps/georchestra/?uuid=b3e098ca-e681-4910-9099-0e25d3b4cd52&hl=eng .

     

Descriptive epidemiology of fractures occurring in British Thoroughbred racehorses in training

REASONS FOR PERFORMING STUDY: Musculoskeletal injury is the major cause of days lost from training and wastage in Thoroughbred racehorses. Little scientific information is available on the majority of injuries occurring in training. OBJECTIVES: To estimate the incidence of fractures in British racehorses in training and describe the occurrence of different fracture types and bones involved. METHODS: Thirteen UK racehorse trainers participated in a prospective study, providing data on horses in their care for 2 years. Details on horses, their daily exercise and fracture occurrence were recorded. RESULTS: A total of 1178 horses provided 12,893 months at risk. Nontraumatic fracture incidence was 1.15/100 horse months (95% CI = 0.98, 1.35) and 78% of fractures occurred during training. A wide variety of fracture types and bones were involved, although at least 57% were stress fractures. Pelvic and tibial stress injuries accounted for 28% of fractures diagnosed. CONCLUSIONS: It is important to study injuries in training as well as in racing. The number of stress fractures suggests that training regimes for young Thoroughbreds could often be improved to create a more robust skeleton, able to withstand injury. POTENTIAL RELEVANCE: Studying injuries in racehorses in training can provide a scientific basis for the design of safer training regimes.     

The combination of PRRS virus and bacterial endotoxin as a model for multifactorial respiratory disease in pigs

This paper reviews in vivo studies on the interaction between porcine reproductive and respiratory syndrome virus (PRRSV) and LPS performed in the authors' laboratory. The main aim was to develop a reproducible model to study the pathogenesis of PRRSV-induced multifactorial respiratory disease. The central hypothesis was that respiratory disease results from an overproduction of proinflammatory cytokines in the lungs. In a first series of studies, PRRSV was shown to be a poor inducer of TNF-alpha and IFN-alpha in the lungs, whereas IL-1 and the anti-inflammatory cytokine IL-10 were produced consistently during infection. We then set up a dual inoculation model in which pigs were inoculated intratracheally with PRRSV and 3-14 days later with LPS. PRRSV-infected pigs developed acute respiratory signs for 12-24h upon intratracheal LPS inoculation, in contrast to pigs inoculated with PRRSV or LPS only. Moreover, peak TNF-alpha, IL-1 and IL-6 titers were 10-100 times higher in PRRSV-LPS inoculated pigs than in the singly inoculated pigs and the cytokine overproduction was associated with disease. To further prove the role of proinflammatory cytokines, we studied the effect of pentoxifylline, a known inhibitor of TNF-alpha and IL-1, on PRRSV-LPS induced cytokine production and disease. The clinical effects of two non-steroidal anti-inflammatory drugs (NSAIDs), meloxicam and flunixin meglumine, were also examined. Pentoxifylline, but not the NSAIDs, significantly reduced fever and respiratory signs from 2 to 6h after LPS. The levels of TNF-alpha and IL-1 in the lungs of pentoxifylline-treated pigs were moderately reduced, but were still 26 and 3.5-fold higher than in pigs inoculated with PRRSV or LPS only. This indicates that pathways other than inhibition of cytokine production contributed to the clinical improvement. Finally, we studied a mechanism by which PRRSV may sensitize the lungs for LPS. We hypothesized that PRRSV would increase the amount of LPS receptor complex in the lungs leading to LPS sensitisation. Both CD14 and LPS-binding protein, two components of this complex, increased significantly during infection and the amount of CD14 in particular was correlated with LPS sensitisation. The increase of CD14 was mainly due to infiltration of strongly CD14-positive monocytes in the lungs. The PRRSV-LPS combination proved to be a simple and reproducible experimental model for multifactorial respiratory disease in pigs. To what extent the interaction between PRRSV and LPS contributes to the development of complex respiratory disease is still a matter of debate.     

In vivo studies on cytokine involvement during acute viral respiratory disease of swine: troublesome but rewarding

The early cytokines interferon-alpha (IFN-alpha), tumour necrosis factor-alpha (TNF-alpha), interleukin-1, -6 and -8 (IL-1, -6, -8) are produced during the most early stage of an infection. The activities of these cytokines have been studied extensively in vitro and in rodents, but in vivo studies on the role of these cytokines in infectious diseases of food animals are few. This review concentrates on in vivo studies of cytokine involvement in infectious respiratory diseases of swine, with an emphasis on viral infections. First evidence for the role of early cytokines in pneumonia in swine came from experimental infections with Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae. The role of TNF-alpha and IL-1 in the symptoms and pathology of porcine pleuropneumonia has recently been proven by use of an adenovirus vector expressing the anti-inflammatory IL-10. In the authors' laboratory, studies were undertaken to investigate the relationship between viral respiratory disease and bioactive lung lavage levels of IFN-alpha, TNF-alpha, IL-1 and IL-6. Out of three respiratory viruses-porcine respiratory coronavirus (PRCV), porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SIV)-only SIV induced acute respiratory disease and severe lung damage by itself. Disease and lung pathology were tightly associated with the simultaneous production of IFN-alpha, TNF-alpha, IL-1 and IL-6. In challenge studies of SIV-vaccinated pigs, levels of IFN-alpha, TNF-alpha and IL-6, but not IL-1 were correlated with clinical and virological protection. Multifactorial respiratory disease was reproduced by combined inoculations with PRCV or PRRSV followed by LPS from Escherichia coli. In comparison with the respective single inoculations, which were subclinical, there was a true potentiation of disease and production of TNF-alpha, IL-1 and IL-6. TNF-alpha and IL-6 were best correlated with disease. In further studies, we will use more specific strategies to dissect the role of cytokines during viral infections.