A Green Energy Dilemma?

The demand for energy has increased by 3.6% in the past 30 years (Saidur et al, 2011). Renewable energy sources are consistently proposed as ways of meeting this demand whilst reducing our CO2 output, thus slowing down our contribution to climate change, and also of halting our unsustainable use of fossils fuels. All renewable energy sources have their critics, though, and Wind Turbines often generate protest when someone proposes constructing a wind farm.

There's the NIMBY (Not In My Back Yard) groups who claim they're a blot on the landscape, and there is large concern that homes near wind-farms lose up to a third of their value (Express & Echo, 2013). It is no surprise that recent plans to construct turbines in Ireland (Telegraph, 2014), Wales (WalesOnline, 2013) and Scotland (BBC, 2013) have been opposed. Personally I find wind-farms a pleasant site, though that might have something to do with having grown up in the industrial north with Teesside power-station, the former ICI (now Syngenta) chemical works, and the Hartlepool nuclear power-station sandwiching my home-town. If they're being built out at sea, there are still groups who claim they're aesthetically unappealing, and then there's the issue of cloud formation behind the turbines, that may reduce visibility and pose threats to sea-faring vessels (Emeis, 2010).

My focus upon both onshore and offshore wind-farms, however, will be the apparent threats they pose to bats and birds. Are the number of fatalities of flying animals really as high some groups make them out to be? And do wind-farms result in more or less deaths than other methods of energy production?

Saidur et al (2011) proclaim that wind energy "is the energy source that is most compatible with animals and human beings in the world". Though bird mortality does occur, wind turbines have been demonstrated to kill fewer birds (~20 times) than fossil fuels, and many more times less than human activities. Amongst anthropogenic causes, building windows largest cause of bird mortality with 97-976 million deaths a year. Pesticide poisoning causes a further 72 million deaths, direct hunting more than >100 million deaths, and collisions with cars and trucks around 50-100 million fatalities. (Sovacool, 2013)

A recent study by Sovacool (2013) estimated that whilst fossil fuel power stations are responsible for roughly 5.2 deaths per gigawatt-hour (Gwh) of electricity, wind farms and nuclear power stations only account for between 0.3 and 0.4 fatalities. In the USA alone, this estimate means that an estimated 20,000 birds have been killed by wind farms in 2009, but over 14 million by fossil fuel power plants.

The number of avian deaths per year in 2009 in the United States - from (Sovacool, 2013).

There are direct and indirect ways in which electrical generation can impact upon birds and other wildlife. Wind farms pose threats during their construction, and the construction of associated infrastructure; large areas of land, roughly 2.5 acres per turbine, are also required (Katz, 2010). Fossil fuel stations post the same threats, and even more. Emissions such as mercury, which is especially a threat to water birds, may lead to fatalities. Acid rain pollution is another threat, causing an estimated 0.5 deaths per GWh, and climate change as a result of CO2 equates to around 4.98 deaths per GWh.

The number of bird and bat collisions with turbines has been show to correlate with weather conditions, with poor weather leading to a greater number of fatalities (Saidur et al, 2011)(Sovacool, 2013). Poor visibility, rain and high winds may lead to birds flying at lower altitudes, becoming disorientated, and birds may become attracted to lights around the wind farms, thus increasing the chances of collision. (Saidur et al, 2011). Older turbines also pose a greater risk as turbines are often spaced more closely and have blades rotating at higher speeds. The lattice-shaped towers of older turbines may also attract nesting birds (Saidur et al, 2011).

Though collision is an issue, the greatest risks to bats appears to be the rapid reduction of air pressure around wind turbines, which leads to fatal barotrauma; the rupturing and internal haemorrhaging of bats' lungs. Barotrauma is not an issue for birds, as their lungs are more adapted to sudden changes in pressure (Sovacool, 2013).

Overall, it is undeniable that Wind Farms pose a threat to birds and other avian animals, but the threats are much less than those of Fossil Fuel plants. I think it important that instead of fighting against protests against wind power, that we instead focus upon ways to reduce the risk to birds and bats, and ways to decrease their offensiveness towards people.

Wind turbines on the Isle of Lewis, Scotland - image by Lews Castle UHI on Flickr.

Minimising motion smear, the blurring of the tips of the turbine blades because of their high speed, has been proposed by Hodos et al (2001) as a way to reduce avian collisions with turbines. They suggest that patterning the blades of the turbines will help birds see turbines more clearly.

Active damping systems may help neutralise the low buzzing noise that wind turbines give off, thus allowing them to be operated at a full load whilst not disturbing local residents (Alternative Energy, 2008). An alternative to building traditional turbines may be instead to use existing infrastructure for wind turbines, such as placing them inside of electricity pylons. By locating the turbines in or on existing structures, complaints that they are an eyesore may be reduced (Alternative Energy, 2009). In China, street lights have been erected in PingQuan with small wind turbines (and two solar panels) atop each structure (Urban Green Energy, 2012); small scale projects like this may be useful for powering local infrastructure, thus reducing the amount of energy required from other sources.

Merry Christmas, and a Happy New Year!

[image source]

Climate Change 2. - Where are the sandeels?

Over the summer I spent two weeks as a residential volunteer on the RSPB reserve at South Stack, Holyhead. During that time, I lost count of how many times I was asked 'Where are the puffins?'. Only once, however, was I asked 'Where are all the sandeels, then?'.

Until mid-to-late July, South Stack cliffs host to around 10,000 breeding birds; mostly guillemots, but approximately 1,500 razorbills too, along with a handful of other birds such as puffins, kittiwakes and fulmar.

Who are you calling a penguin?! Razorbills (Alca torda) on South Stack Cliffs. The guillemots and razorbills spend their lives at sea, and only venture onto land to breed. 

A large part of the diet of these seabirds during the breeding consists of sandeels; several species of slim, eel-like fish that occur in shoals that are important in linking together many trophic levels of the marine ecosystem. The primary species fed upon by bird colonies in the North Sea are the adult lesser sandeels (Ammodytes marinus) which, like all sandeels, burrow into soft sandy substrates with which they are closely associated. Their distribution is therefore restricted to areas in which such substrates are found, and as a result these fish are unable expand their ranges into deeper waters to deal with the threats they may face (Scottish Gov, 2010).

A reduction in the sandeels available with not only effect species of seabirds -Kittiwakes in particular-, but also marine mammals such as harbour porpoises (MacLeod et al, 2007) and up to 10 species of predatory fish (van Deurs et al, 2009). Sadly, sandeel populations have been declining in number, and this in turn has been linked to a reduction in sea-bird populations which struggle to feed themselves and their young. Between 1986 and 2011, the number of seabirds breeding around Scotland decreased by 53%, and the decline is believed to be due to a drop in sandeel availability (Herald Scotland, 2012).

So, where are all the sandeels going?

The population decline of the sandeels has been linked to two anthropogenic causes:

• Climate change, resulting in a warming of the UK coastal waters since 1980 of up 1°C per decade (Wanless et al, 2010).
•  Over-fishing for commercial purposes, such as for fish-meal feed and fertiliser.

Sandeel population decline has been correlated with rising sea temperatures by several authors (Wanless et al, 2010) (Heath et al. 2012). As the seas warm, the cold-water zooplankton that the sandeels feed upon are replaced by less nutritious warm-water varieties (Wanless et al, 2010). Though the cold-water species are still found in cooler, deeper waters, the habitat restriction of the sandeels means they cannot follow the cold-water zooplankton as they migrate (Heath et al. 2012). As a result, the sandeel populations experience a decline.

Rising sea levels are also thought to be posing a threat to the sandeels, though overall the effects of anthropogenic climate change on Ammodytes is not fully understood, and research is still ongoing as a result.

Whilst over-fishing is not thought to be the primary cause of sandeel decline, it makes it harder for the climate-hit sandeels to fight back. In turn, this affects seabirds; Sandeel exploitation has been linked to declining kittiwake colonies near to fishing grounds.

Plans were announced in November 2012 to halt the decline in seabird numbers (Scottish Seabird Centre). One of these plans involved the inclusion of sandeel habitats in the Scottish Government's Marine Scotland agency's network of Marine Protected Areas where there are imposed fishing limits. It is hoped that these fishing limits will halt the decline in sandeel numbers, which in turn is anticipated to stem the decline in seabird populations.

The Orange-bellied Parrot - Colourful but Endanged Aussies

Before starting up this blog I had no idea that so many parrot species (well, just birds in general) were classed as Endangered or Critically Endangered. Partly it's because I never knew there were so many different species out there, and partly because -in the case of parrots- you can walk into pet shops and see them lined up in cages. I used to assume that if they were being sold to the general public, they were clearly in abundance in the wild.

How wrong I was; of the popular cage bird species, several are classified as 'threatened' on the latest IUCN Red List. Amongst those that are Vulnerable is the African Grey Parrot (Psittacus erithacus), and several others are classed as Endangered, amongst them being the Hyacinth Macaw (Anodorhynchus hyacinthinus) and the Red-fronted Macaw (Ara rubrogenys).

The Orange-bellied Parrot (Neophema chrysogaster) (BirdLife, 2013) is an example of a Critically Endangered parrot, but as far as I'm aware these little guys aren't available as pets. It could argued that such a thing is as good as it is bad; a lack of demand for the pet trade means that nest poaching is much less likely, but it also means that there are few people breeding these birds in captivity. The gem coloured birds are incredibly rare; found in Southern Australia and Tasmania, their population in the wild estimated to be lower than 50 individuals, with a decreasing trend. Between 2000 and 2008, there was an observed 12% decline in the number of adult birds at breeding grounds. This is thought to be due a lack of female parrots attempting to breed, which in turn results in a decline in the recruitment of juveniles to the species' population (Holdsworth et al, 2011).

The Critically Endangered Orange-bellied Parrot (Neophema chrysogaster) - image by Ron Knight on Flickr.

A number of factors are believed to be behind the declining population, and the majority of these are anthropogenic. Agriculture and urbanisation, along with industrial developments, fragment and degrade the important overwintering habitats of Southern Australia. Salt-marsh habitat degradation is also classified as a large threat, and worries have been voiced that proposed mining in Tasmania at Melaleuca could significantly damage breeding grounds. Looking at invasive species, various introduced seed-eating finches compete with the parrots for available winter food, and common starlings (Sturnus vulgaris) take-over nesting sites previously used by the parrots.

Random events also impact upon the species' population, though some of these events may become less random in years to come. Death from storms during migration may rise if storm frequency and intensity increases with future climate change. Disease is another danger, especially when the population is so small. Between 2005 and 2006, 40 birds bred in captivity died due to a suspected viral disease. The population was quarantined to prevent any disease spreading to the wild population, but things may not be as lucky in future. Other threats proposed by BirdLife Australia (2012) include the risk of predation by cats and foxes, inbreeding, deaths from collisions with structures such as wind turbines, and threats from noxious weeds.

It all paints a pretty grim picture for the Orange-bellied Parrot, doesn't it? Nonetheless, things may be looking up for these Aussies!

A breeding programme has been in place since 1986, which aims to increase numbers in the wild by releasing birds bred in captivity into the wild (Tasmania Parks & Wildlife Service, 2013). In 2006, $3.2 million was committed to help expand and protect the population and habitat of the parrots. The conservation attempt encompasses many things, including enhancing the captive breeding program in place, conservation of the breeding and nesting habitat in Tasmania, expansion and protection of the winter nesting grounds in Australia, and control of predators in breeding, migratory and wintering habitats (BirdLife Australia, 2012).

21 young birds were taken from nests in 2011, from where they were transferred into a captive 'insurance population' that currently numbers over 200 individuals. To boost the numbers in the wild, 23 members of this population were released this year. It's hoped that these newly released birds will integrate into the wild population and breed in the following years, thus reserving the population decline (Stephen Garnett, 2013). Hopefully this means we'll be seeing some good news regarding orange-bellied parrot in the next few years to come!

Bird Friendly Tuna?

Many albatross and petrel deaths attributed to pelagic long-line fishing for tuna and similar species in the southern hemisphere. In a study of seabird deaths due to pelagic longline fishing in the southern Atlantic Ocean between 2004 and 2008, Yeh et al. (2012) estimated that between 3446 and 6083 birds were killed per year. These deaths lead to many breeding-site populations reducing in number (Roberston et al, 2013).

A shoal of Skipjack Tuna (Katsuwonas pelamis) - image
from Wikipedia Commons.

There are ways to reduce mortality, such as setting lines at night, but this method -and several others- may mean that industries are unable to set their lines at times that optimise catch rates.

Robertson et al. (2013) suggest that focusing on branch-line weighting may be a way of reducing mortality rates of seabirds in the Australian fishing industry. Weights are not a new innovation in longline fishing, but Robertson et al. (2013) carried out experiments that differed from previous weighting methods. In their tests, weights were positioned differently upon the lines; in the first test, a 120g weight was placed ≤ 2m from the hook, and in the second test a 40g weight was placed directly at the hook. The purpose weighting the lines is to reduce time it takes for the hook and its bait to sink, thus reducing risks to seabirds by reducing the exposure of bait at the surface where birds may become caught.

Concern is often expressed that weights reduce catch, but Robertson et al. (2013) found no reduction in catch rates of Yellow-fin tuna; rather, catch rate correlated with bait type. For the other species caught, neither weighting or bait type seemed to have an effect on catch rates.

Though the heaver weighting method had faster sink rates, the authors acknowledged the implications of the extra weight in the gear bins. For this reason, they suggest using the lighter weighting method. They also indicate concerns for the loss of lead weights through shark bite-offs. Though not so much an economic problem, there is some concern that lead weights will become deposited on the seabed, or that they could be swallowed by sharks which may be later caught for human consumption. A way round this dilemma would be the replacement of lead with another substance.

Robertson et al. (2013) also state that loss from bite-offs may be minimised by placing weights on shorter leads; having the weights nearer hook is also safer for members of the fishing crew, as their experiments show such placement to reduce 'fly back' of the weights when hooks are bitten off. Other benefits they raise are reduced labour times for fishing crews due to less tangling and less like breakage (and therefore less repairs) of lines, as well easier line deployment.

New weighting regimes therefore seem like a win-win situation for both seabirds and the fishing industry. I just don't think the tuna will be all that happy...

To Plant, or Not to Plant? - A Reforestation and Afforestation Dilemma?

There's a great post covering deforestation over at Harmonising Humans & Nature, so I won't bore you with the facts. There's no way we can deny that deforestation is unsustainable and having a vastly negative impact upon the Earth's ecosystems; 70% of the worlds land organisms live in forests, yet deforestation destroys the habitats of these plants and animals (National Geographic). With all this said, it seems that right thing to do would be to stop cutting down the trees and re-plant them; either where they once stood, or elsewhere.

Sadly, things are never as straight forward. Planting trees or letting natural succession take place until areas once wooded long ago are reforested may, in some areas, impact negatively on biodiversity. Planting forests where there were once no forests (afforestation), to replace those lost elsewhere, can also have detrimental effects - often more so than reforestation.

We humans have been shaping and leaving our footprints upon this planet for tens of thousands of years, and animals have partly evolved to coexist with us. Landscapes have been anthropogenically modified in Western Europe, through deforestation and agriculture, for at least 4000 years; in Asia this modification is likely to have been going on for even longer (Anson Mackay, 2013). This causes a dilemma, as though many argue for returning habitats to their 'pre-human' state, the animals now living in these 'new' habitats may have adapted to them, or may not be the original organisms that previously lived in the area.

 Rannoch Moor, Scotland; A natural peat-land, though many bogs are present due to human modification and management of the landscape in the northern hemisphere  - image by Martin Sojka on Flickr.

Reforestation and afforestation are generally beneficial; both can increase biodiversity, have economic benefits (such as providing timber), can reduce soil erosion and run-off, and reforestation can help restore natural habitats (Reino et al, 2010). However, both may also have negative impacts on plant and animal species that have adapted to a woodland-free environment. 

After the abandonment of traditional mountain agriculture in many regions, natural reforestation can lead to a loss of open spaces which has been linked to a decline in grassland plant species that are vulnerable to landscape fragmentation (Sitzia et al, 2010). Though reforestation is beneficial for alpine birds whose species often experience population increases, Sitzia et al, (2010) noted that landscape fragmentation can act negatively upon species unable to live in small, patchy habitats.

Two studies into the effects of anthropogenic afforestation of Mediterranean farmland in the Iberian Steppes of Spain show the negative effects that afforestation may have in certain regions, including the direct loss of habitat for species of conservation concern, and increase in the abundance of predators (Reino et al, 2009)(Reino et al, 2010).

Whilst the planting of forests may lead to an overall increase in bird abundance and diversity in farmlands adjacent to forest patches, the overall increase is at the expense of grassland specialists (Reino et al, 2009). Steppe birds show strong negative edge effects, with the abundances of Calandra Larks and Short-toed Larks in particular depleted in grasslands directly adjacent to forest plantations. The abundances of these species increased further away from the edges of the plantations, and the highest species abundance and richness were observed in large arable patches. Though both species were listed as 'Least Concern' in the latest IUCN Red List report, their populations are in decline (BirdLife, 2013 - Calandra Lark)(BirdLife, 2013 - Lesser Short-toed Lark); habitat loss due to afforestation, which has already been accredited to regional declines of Lesser Short-toed Larks, may lead to greater pressure upon both species.

As the number of forested patches increased, Reino et al (2010) also documented an increase in the abundances of generalist predators, such as foxes and corvids (crows, ravens, magpies...); the increases of which have been associated elsewhere to population declines of ground-nesting birds (Fletcher et al, 2010).

Increased nest predation by predators such as foxes may lead to significant population declines of ground nesting birds, such as Eurasian Curlews in Scotland and Northern England (Douglas et al, 2013) - image by Jans Canon on Flickr.

A recent paper by Douglas et al (2013) on upland land use and declining waders populations highlights another case where afforestation and the fragmentation of moorland has been linked to increased predation rates, this time leading to a decline in breeding populations of the Eurasian Curlew (Numenius arquata), a bird listed as 'Near Threatened' in the latest IUCN Red List due to a 20-30% global population decline in the last 15 years (BirdLife - Eurasian Curlew, 2013). Both Douglas et al (2013) and Fletcher et al, (2010) also noted that predator control can help prevent population declines in species of conservation concern; for Lapwings, Curlews, Red Grouse and Golden Plovers, predator control lead to an observed population increase of ≥14% per annum, whilst a lack of predator control saw populations decrease by ≥17% per annum (Fletcher et al, 2010). 

The Eurasian Curlew, Numenius arquata - image by Davis Kwan on Flickr.

Though in the study by Reino et al (2010) it was concluded that nest predation rates (on artificial nests) showed no relation to predator abundances in the Iberian Steppes, they suggest that landscape composition and configuration may instead have a stronger impact due to edge density effects.With this, they recommend that afforestation in the Mediterranean -and other areas inhabited by ground-nesting birds of conservation concern- be avoided where possible. Where afforestation is unavoidable, they insist that populations be monitored closely for signs of declining numbers due to predation. They also suggest aiming to reduce habitat fragmentation and edge effects by afforesting a smaller number of large patches, rather than planting many relatively small patches (Reino et al, 2009).

References:

• Biodiversity and Landscape Change (Lecture) - Anson Mackay, 2013