Plant and soil intake by organic broilers reared in tree- or grass-covered plots as determined by means of n-alkanes and of acid-insoluble ash

Free-range birds such as organic broilers may ingest soil and plants during exploration. The estimation of such intakes is of great interest to quantify possible nutritional supplies and also to evaluate the risk of exposure to parasites or to environmental contaminants. Marker-based techniques are now available and would allow to quantify plant and, especially, soil intake in free-range birds, and this quantification was the aim of this study. Methodologically, the proportion of plants in diet intake was determined first using a method based on n-alkanes. Subsequently, the fraction of soil in the total intake was estimated with a second marker, acid-insoluble ash. This approach was carried out to estimate ingested amounts of plants and soil for five successive flocks of organic broilers, exploring grass-covered yards or those under trees, at two time points for each yard: 51 and 64 days of age. Each factor combination (yard type×period=flock number×age) was repeated on two different yards of 750 broilers each.The birds’ plant intake varied widely, especially on grass-covered yards. The proportion of plant intake was significantly higher on grass-covered plots than under trees and was also affected, but to a lesser extent, by age or flock number. The ingestion of plants would generally not exceed 11 g of DM daily, except two extreme outliers of nearly 30 g. The daily plant intake under trees tended to be lower and never exceeded 7 g of DM. The amount of ingested plants increased significantly for spring flocks. It increased slightly but significantly with age. The proportion of ingested soil was significantly higher under trees than on grass-covered yards. Dry soil intake was generally low with not more than 3 g per day. Only in adverse conditions – that is, older birds exploring yards under trees in winter – soil intake reached the extreme value of nearly 5 g. Broilers on yards under trees ingested significantly more soil than on grass-covered yards with least square means of, respectively, 2.1 and 1.1 g dry soil per day. These quantifications would allow us to evaluate the impact of plant and soil intake in the management of free-range broilers, especially for the management in organic farming systems. Nevertheless, under the two rearing conditions tested in the current study, the quite low proportions of soil intakes would represent a low risk for the safety of the produced food, unless the birds explore yards on heavily contaminated soil.     

Temperature thresholds for germination in 20 short‐range endemic plant species from a Greenstone Belt in southern Western Australia

• The study of climate‐driven effects on seed traits such as germination has gained momentum over the past decade as the impact of global warming becomes more apparent on the health and survival of plant diversity.
• Seed response to warming was evaluated in a suite of short‐range endemic species from the biodiverse Greenstone Belt of southern Western Australia. The temperature dimensions for germination in 20 woody perennials were identified using small unreplicated samples over 6 weeks on a temperature gradient plate (constant and fluctuating temperatures between 5 and 40 °C). These data were subsequently modelled against current and forecast (2070) mean monthly minimum and maximum temperatures to illustrate seasonal changes to germination timing and final percentage germination.
• All but one species attained full germination in at least one cell on the gradient plate. Modelling of the data suggested only minimal changes to percentage germination despite a forecast rise in diurnal temperatures over the next 50 years. Nine species were predicted to experience declines of between <1% and 7%, whilst 11 species were predicted to increase their germination by <1% to 3%. Overall, the speed of germination is predicted to increase but the timing of germination for most species shifts seasonally (both advances and delays) as a result of changing diurnal temperatures.
• The capacity of this suite of species to cope with warmer temperatures during a critical early life stage shows a degree of adaptation to heterogeneous environments. Predicting the effects of global change on terrestrial plant communities is crucial to managing and conserving plant diversity.

     

Movement patterns and space use of the first giant anteater (Myrmecophaga tridactyla) monitored in São Paulo State,Brazil

This study analyzes a giant anteater’s (Myrmecophaga tridactyla) movement patterns and space use in São Paulo, Brazil. It is the first study to track a giant anteater with Iridium-GPS. The anteater traveled an average distance of 1326 m day^–1 with an average speed of 1.04 m min^–1. Home range by Kernel was 2.46 km² while the core area was 0.75 km², and estimates by Brownian bridge and minimum convex polygon were also provided. The anteater used shrub savanna, open savanna, and water habitats more than expected. Monitoring ended just after 10 days when the female giant anteater’s GPS was found on an illegal trail.     

Dating lightning: Dendrochronological and magnetic analyses of lightning scars

Lightning impacts on forests and trees are still understudied from a tree-ring perspective. Lighting causes direct and indirect damages on forests and trees. Trees struck by lightning can show a growth reduction and lightning storms also trigger wildfires in seasonally dry areas such as Mediterranean mountains. Here we combined dendroecological and magnetic analyses to reconstruct and assess the impact of lightning on radial growth and the magnetic properties of wood in Scots pine (Pinus sylvestris) and Black pine (Pinus nigra) in two sites with a high density of lightning impacts located in eastern Spain. We dated several lightning scars, particularly in Scots pine, formed during 1982, when a wildfire was initiated by lightning during a dry summer storm. Growth was reduced during the year when the scar was formed in both pine species, albeit this effect could be masked or amplified by other disturbances (drought, outbreaks). However, despite that short-term growth reduction scarred trees showed higher growth rates than non-scarred trees in the case of Scots pine. The intensity of magnetization did not significantly differ in wood produced before and after the lightning scar was formed. This could be due to multiple lightning hits in the same or nearby stands affecting the magnetization of wood. Wood magnetic properties should be further explored as proxies of lightning impacts in sites where scars are not formed and tree-ring information is limited such as tropical forests. Further cross-disciplinary research is required to assess the impacts of lightning on tree growth and magnetism.