​A desolate barren wasteland devoid of life, with the occasional researcher in a hazmat suit and a Geiger counters incessantly clicking as they wonder around the hellscape that used to be Chernobyl. That may be along the lines of what most people think the area around Chernobyl, the site of the worst nuclear disaster the world has ever seen, looks like. Either that or somewhere that harbours strange mutants with odd numbers of eyes or limbs. The truth actually tells us far more about human impacts on the environment than it does the effects of radiation.
 
In reality, as a study that was recently widely reported and covered in the press. (e.g. the Guardian and the Conversation), wildlife is flourishing within the restricted zone that surrounds the former power station. The conclusion to inevitably draw from this is that humans are worse than a nuclear accident. Radiation in high levels or ingested can be very dangerous, to both animals and humans, but at even relatively high levels (which do occur naturally in places like Cornwall, Aberdeen and Ramsar in Iran) radiation isn’t as much of a problem as many people believe. Years of fears about Hiroshima have led us to fear radiation, but it occurs naturally all around us every day. It’s only natural to transfer those same fears and misunderstanding to the impact of radiation on animals.
 
There have been studies in the Chernobyl exclusion zone, most notably from Anders Møller, that have shown negative effects. But the overwhelming evidence is that the lack of humans, who destroy habitats, hunt and spray pesticides and herbicides, is a much bigger positive than the negative of radiation. This should be a wakeup call to governments around the world, not only for the preservation of terrestrial ecosystems but for marine ecosystems as well. Having large areas of land, big enough to allow viable populations of predators and prey, and leaving them almost completely free of human influence is good for biodiversity. This is going to become increasingly important as pressure for land intensifies with growing populations. Increasing the connectivity of small reserves and parks and maintaining the greenbelts around urban areas in countries like the UK are crucial to maintaining our native wildlife.
 
I think that in the long run this type of research will do the conservation movement a lot of good, as the idea that we are worse for the environment than a nuclear disaster is a strong one that sticks in the mind.

​This is going to be a drastic departure from the topics that I normally blog about. However, I hope it is still interesting to people who regularly read my ramblings about evolution and animal behaviour.
 
The reason for this post is that it’s a topic I’ve been working on at work and some of the things that I have found have shocked me slightly. The topic is chemical regulation, something that has never interested me before but has a big impact on our day to day lives. This is a brief commentary on its speed and what rules are used to govern it,
 
Firstly, a good place to start with chemicals is to understand that, for most, the dose makes the poison. So for most chemicals if you receive a low dose then you’ll suffer no ill effects. But sometimes things like timing of exposure have a big impact on humans, e.g. thalidomide, or the dose may be fine for us but not so fine for wildlife.
 
Secondly, there are two ways of assessing if a chemical is going to be bad for us: hazard based assessment or risk based assessment. In a nutshell, hazard based roughly says that if any chemical is bad then it should be banned, whereas risk based looks at likelihood and level of exposure as well. Risk based is probably better but only if you have good data on exposure likelihoods and levels, otherwise it’s just guesswork. This article briefly goes over the debate in Europe about which system to use: LINK. Out of this type of debate the Precautionary Principle has arisen, basically safety first, but a lot of people say that this is unscientific because it doesn’t take risk into account.
 
So why am I writing about this? Well as a scientist I think that risk based is probably the most sensible but after looking into two chemicals Tributylin (TBT) and Diethylstilbestrol (DES) I am not so sure anymore.
 
The case of TBT:
This chemical was used as an antifouling agent on boat, to stop barnacles etc growing on the hulls of ships and other aquatic craft. It did a great job, but one problem: it inhibits the Cytochrome P450, which is involved in converting androgens to oestrogen. This caused huge number of female molluscs to be unable to get rid of their testosterone and basically grown male(ish) genitalia, something called imposex. This had a huge impact on benthic organisms and impacted on algal growth and young fish too. This was discovered in the 1980s and in some countries it was banned by 1987, but even in those it still has knock on effects to this day. But it took until 2003 for the the International Maritime Organisation to finally officially phase it out.
 
The case of DES:
DES was used as a preventative treatment to stop women having miscarriages and its use started in 1938. However, by the 1953 it had been shown not to help with miscarriage prevention at all. Some not very nice trends started to be noticed by doctors and then Chicago’s Arthur Herbst showed that daughters of mothers who had used DES had a much higher incidence of rare vaginal cancers at early ages. It turns out that from long-term studies that women prescribed DES have higher risk of breast cancer and in addition to cervical cancer daughters are more likely to have reproductive tract problems and difficulties with pregnancy. This drug was also prescribed to girls who were too tall, to stop them growing. It took until 1971 for it to be banned in the US and 1978 for Europe.
 
It took a staggeringly long time for both of these chemicals to be banned for those uses, TBT worst of all because its effects were known in the 80s and it took till the early 2000s to be fully banned.
 
These two examples show how long it can take to show that something is unsafe and should be banned. I’m not advocating for everything that may be hazardous to be banned straight away, but the argument against using the Precautionary Principle is not as simple as Science v Non-science. We must learn from examples like these but do so by developing better and early tests for risk.

A great new piece of research has just been published by some of my old colleagues at the Fitz in Cape Town (Susie Cunningham and Arjun Amar). It’s work that I help with at its inception, and it shows that pied crows have changed their distribution in South Africa and it’s mainly due to changes in climate and the distribution in power lines. A great piece of research that shows how the twin human impacts of climate change and habitat modification are shaping the natural world.
 
Cunningham et al. (2015) Electric crows: powerlines, climate change and the emergence of a native invader. Diversity and Distributions, DOI: 10.1111/ddi.12381
 
Abstract
Aim
Climate change and other anthropogenic global change drivers act in complex, mutually exacerbating ways to alter the abundance and distribution of species. In South Africa, pied crows Corvus albus have increased in numbers and range in recent decades. Popular opinion links these changes to urbanisation and infrastructure development, but there has been no empirical test of this idea. We aimed to clarify the drivers of pied crow population changes in South Africa.
Location
South Africa.
Methods
We used publicly available long-term datasets, the Southern African Bird Atlas Project and University of Delaware Gridded Climate Database, and spatial data from government bodies, to assess relationships between pied crow population and range changes, land use, infrastructure, urbanisation and climate change.
Results
Pied crow numbers have increased significantly in the past three decades, but rate of increase varied geographically, with crows declining in the northeast and increasing in the south-west of South Africa. Pied crow population changes were strongly correlated with climate change. Crows have benefited most from climate warming in the shrubland biomes of south-western South Africa. Pied crows are tree nesters, and within these shrublands, there is a strong positive relationship between the rate of population increase and the density of powerline infrastructure, which may facilitate pied crows’ increase by providing nesting sites.
Main conclusions
Pied crow numbers have increased in response to climate warming, with their spread facilitated by electrical infrastructure in south-western South Africa, providing a clear example of compound influence of multiple global change drivers promoting a significant change in species range and reporting rate. Pied crows are generalist predators and there is popular concern about their ecological impact in areas where increases have occurred. We highlight the importance of understanding the ecosystem-level implications of increased numbers of pied crows in South Africa's shrubland biomes.

Link: http://onlinelibrary.wiley.com/doi/10.1111/ddi.12381/abstract

The marine environment is one that for most of human history was thought to be an inexhaustible supply of food. The great expanses that cover two-thirds of the globes surface seemed to provide a bountiful harvest for humanity. However, we're increasingly becoming aware of the huge impact that we have had and are having on our oceans.

A recent report from the WWF has just found that in the last 40 years fish populations have fallen by over half. For major commercial species such as tuna, mackerel and bonitos the decline has been as much as 74%. These declines are from a combination of over exploitation of fish stocks and habitat loss. Habitats such as mangroves are crucial breeding grounds for many marine species, but they're the types of areas that are built on or destroyed. Without mangroves and seagrass beds fish stocks will be slow to recover.

This report comes on the back of a recent paper published in Science that found that humans kill adult prey at a rate 14 times higher than any other species. Our impact is especially felt on terrestrial predators and fish. Human impacts are felt even stronger because of the age group of animals we impact on: adult individuals of reproductive age. Most predators kill juvenile or sick members of their prey species but by killing the reproductive adults we have a disproportionate impact on the ability of the species to replenish its numbers. 

The oceans are not an environment that we can easily see or come in contact with. They are remote and difficult for us to understand. This may be one of the reasons why so many people seem not to understand how endangered life in the seas is. They are communal resources that any country with a coast line can access and their vastness prevents them being policed. With everyone being able to access them the tragedy of the commons takes hold. This means that to solve the problems of the worlds oceans we are going to need major international efforts to police the the seas and to tackle climate change, as one factor in the decline of the worlds fish stocks is ocean acidification (due to increased CO2 levels) reducing negatively impacting coral reefs.