The effect of copper stress on inter-trophic relationships in a model tri-trophic food chain.

Soil fertility and management are paramount in ensuring food security for the growing populations. The use of agri-chemical and products containing heavy metals inadvertently threaten both food security and the surrounding ecosystems from contamination, loss of productivity or ecosystem service. In the present study a series of experiments on the toxic and adaptive responses of wheat plants to copper-induced stress were conducted to establish the effects of different levels of Cu (0 – 200 mg kg -1) on growth, nutrient levels and the total plant proteins of wheat seedlings (Triticum aestivum) using pot experiments. A tri-trophic food chain soil → plant → herbivore → predator was established as plants were infested with grain aphids (Sitobion avenae) which were subsequently fed to predatory ladybirds (Adalia bipunctata). Multiple measurements were conducted which deduced that Cu was taken up from soil into the plant tissues accumulating in the shoot and ear. The rate of growth and flag leaf length were affected by levels of Cu in the soil but total plant mass and ear weights were not. Wheat shoots and ears were analysed for N (crude protein) P, K and it was found that the levels of Cu in soils affected the levels of protein in both the shoot and the ear while the levels of P and K remained unaffected. Total populations of aphid and aphid fecundity appeared to be unaffected by the Cu stress-induced plants and no significant relationships between levels of N in plant tissues or flag leaf length were found. Ladybirds also appeared to be unaffected by the levels of Cu in soils as consumption rate or change in mass between the treatments was not significant. While the present study does not support a critical threshold for Cu levels in agricultural soils it can conclude that biological control methods are unaffected by levels of Cu in the soil

Conducting robust ecological analyses with climate data

Although the number of studies discerning the impact of climate change on ecological systems continues to increase, there has been relatively little sharing of the lessons learnt when accumulating this evidence. At a recent workshop entitled ‘Using climate data in ecological research’ held at the UK Met Office, ecologists and climate scientists came together to discuss the robust analysis of climate data in ecology. The discussions identified three common pitfalls encountered by ecologists: 1) selection of inappropriate spatial resolutions for analysis; 2) improper use of publically available data or code; and 3) insufficient representation of the uncertainties behind the adopted approach. Here, we discuss how these pitfalls can be avoided, before suggesting ways that both ecology and climate science can move forward. Our main recommendation is that ecologists and climate scientists collaborate more closely, on grant proposals and scientific publications, and informally through online media and workshops. More sharing of data and code (e.g. via online repositories), lessons and guidance would help to reconcile differing approaches to the robust handling of data. We call on ecologists to think critically about which aspects of the climate are relevant to their study system, and to acknowledge and actively explore uncertainty in all types of climate data. And we call on climate scientists to make simple estimates of uncertainty available to the wider research community. Through steps such as these, we will improve our ability to robustly attribute observed ecological changes to climate or other factors, while providing the sort of influential, comprehensive analyses that efforts to mitigate and adapt to climate change so urgently require