Feeding the Song Birds

February 28, 2014

Things that healthy birds do not need – beware what is put on the bird table!

The advice being passed down to the bird loving public, often takes no account of the biology of the birds!

Birds are like humans, they will flock to eat stuff that is really bad for them.  Research work over the past 50 years on bird rearing agrees with me, and demonstrates that a diet of fat results in increased deposits of internal fat especially around the gonads.  This problem is made worse by the fact that the body uses fat as a storage organ, it is in the fat that any chemical pesticides that don’t kill the birds outright, will end up.  This reduces fertility in all species, and so will lead to a further decline in song bird populations.

If you think about it, the only birds that kill fat animals or birds, or that you see on ‘road kill’ are the raptors and corvids.  These are not normally the birds that you want to attract to your bird table as they have a habit of killing the smaller song birds.  Likewise, our birds do not naturally crack open nuts for the very simple reason that the only nuts native to this country are hazelnuts and pine nuts.  The former are so hard that only squirrels and mice can get into them; whereas the latter are eaten by the Crossbills – whose beaks are specially adapted to winkling the pine nuts out of the pine cones.  The little Goldcrests and Firecrests that also breed and shelter in coniferous forest, are feeding on aphids, springtails, small flies, grubs, and pollen, but not the nuts that they could never reach!

For a healthy song bird population, try to give your garden birds more of the foods that grow naturally in this country.  Remember too that very few, if any, birds are complete vegetarians.  They do eat small grains, seeds and berries in the autumn, but for most of the year, they feed on whatever insects, worms and grubs that they can find, supplemented by a peck or two of annual herbs e.g. dandelion leaves.  So in the winter, supplement their natural food with small grains etc; but better still, do all you can to promote small insects, bugs, spiders, worms and fresh leaf growth e.g. of dandelions etc.  These are all really good for the birds in this country, and will not cause them to lay down unnatural fat around their internal organs.

The other thing that is needed by over-wintering birds is natural cover.  Dense thickets of brambles are excellent, providing both cover and insects; while standing under our line of Lawson cypress trees at my own home on a winter’s evening, revealed the song birds’ favourite spot.  They would congregate up in the branches under the thick evergreen cover of the conifers and chirp away, warm and dry.  Yesterday, visiting a friend in Taunton, I was horrified to see that the Somerset CC had been busy removing a bramble thicket along an area that they had designated as wildlife habitat beside the River Tone – so much for their knowledge of wildlife.  Plus of course, they have removed the possibility of the thousands of humans in the area being able to pick blackberries that are not wrapped in plastic containers, and to actually make their own blackberry and apple jam.  The wild eaters of the blackberries are mostly little field mice, while the birds feast on the spiders and flies that are also attracted to the fruit!

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Ivy – Hell Bent or Heaven Sent

August 24, 2011

Written as a blog in response to a letter by Lt Col Paul French (Rtd.) in the Daily Telegraph of Monday 28th March 2011.

Most of us who love trees for their timber and role in the landscape, regard Ivy as a foe.  The wild variety in the UK is named Hedera helix, though from its growth pattern it would be more aptly named Hedera rete i.e. Ivy net.  However, there are three views of  ivy: that of the tree; that of the birds, bats, insects and fungi that live in and on it; and that of humans and the browsing animals.  In past centuries: before the reign of plastic, huge human populations and high wages; all trees, farmland, woodland and forestry, were cared for by the humans who worked the land.  Ivy was left to grow only on those trees that were already misshapen, or of a species whose timber was not considered to be useful.  Even then Ivy was controlled by deer and cattle that were permitted to seek the shelter of the woods in winter, where they kept down the undergrowth.  Their grazing kept the glades open so that Wild Garlic and Bluebells could get enough sunshine to grow and flower ahead of the herbs and thin grasses in the spring.

Viewed from the tree’s perspective it is definitely a devil.
The creeping stems of Ivy are coated on one side with tiny suction rootlets that enable it to climb up the trunk and cling to the bark of  the tree.  Generally it does not attack until a young sapling has become too inflexible to fling off the unwanted guest as it bends in
the wind.  Then, when after several years the trunk has lost its whippy characteristic, and is suitably firm and steady, the Ivy colonizes.  Unless it is broken off by humans or browsers, ivy grows steadily upwards branching as it goes, until it reaches a level at
which the branches are still whippy enough to shake off the tendrils for the time being.

Like all evergreen species, although it does not shed its leaves seasonally, they gradually age and drop off.  They then cause even more trouble: by lodging in the angles of the boughs, and with other leaves they rot down leaving a black leaf mould that in turn plays host to epiphytes – mosses, nettles and ferns.  The bark beneath then starts to rot, thus weakening the branch, and allowing the rot to penetrate the heart wood of the tree.  The living Ivy leaves also cause problems by sheltering the bark from the rain, and the ‘rootlets’ absorb any water running down the surface of the bark.  This leaves the bark dry, brittle, and cracked so that it is easily penetrated by insects and fungal spores.  These often carry diseases, both bacterial and viral, which are, in turn, transported into the sap that runs in the living layers just beneath the bark.  In this way pathogens can be carried up into the leaves of the canopy or down into the root system.

Worse still Ivy keeps its leaves throughout the winter, thus adding weight to the branches and extra surface area to catch the winds.

The ivy here has climbed nearly to the top of the birch tree and the weight of its leaves is slowly pulling the tree over.

Slow felling of a Birch by Ivy

  This at a time of year when our deciduous trees have shut down and shed their leaves, thus protecting themselves not only from the cold, but also from damage by winter storms.  In a young sapling the situation is not so serious, as it is often both strong and flexible enough to carry the extra leaf area without cracking; especially so since the ivy is young too and equally flexible, but the story is very different for the older tree.  Veteran trees often have ivy stems of over 6cms diameter half buried in their bark; and these vast old creepers add substantially to the weight to be carried by the branches, made even more fragile by the lack of moving sap during the winter months.

The result is very visible damage.  Some unlucky trees are completely thrown and partially up-rooted; some escape; but most veteran trees suffer the breaking of large boughs and even smaller branches in the crown of the tree.  These breaks leave scars that not only spoil the visual shape of the tree, but may also unbalance the tree, making it more susceptible to wind damage in the future; not to mention the increased risk of disease entering the broken timber via rain and spores.  All this damage hastens the slow demise of the tree.  However . . . .

Viewed from the denizens of the tree the story is very different; for everything, that the tree could be expected to regard as negative, is positive to them.  In fact the more the tree is damaged, the better the better it becomes for them.  Though as it disintegrates, they will all have to move on, starting with the birds and insects and ending with the decomposers growing on the rotting wood.  This is the way that it has always been.

In regions where there are no convenient conifers, ivy-laden trees provide some of the only safe shelter for small birds throughout the winter months; besides providing an every ready larder of spiders, flies, beetles, millipedes and mites throughout the year.  Bats too, can be found sheltering under the ivy during the summer; though it is possible that they are really looking for suitable warm sheltered holes to use for winter hibernation.  As for the rest: the birds’ living larder and the fungal spores; the ivy provides warmth, shelter and nice little cracks in the bark with good access to sap – an ideal growth medium for the fungi and any pathogenic bacteria and viruses spread by the insects.  Finally . . . .

Viewed from the requirements of humans and browsers the story becomes split.

On the ‘Up side’, the latter seem to regard Ivy as we would a tasty herb.  However, it is probable that their actions are related to self medication, as Ivy is a known anthelmintic that has been used as such in the past.  Animals may not be able to read books, yet many seem to either know or learn that certain ‘herbs’ are beneficial when eaten in small quantities.  So long as the plant is bitter they don’t exceed the safe dose; it is only when the plant is sweet, either alive or when dead e.g. Ragwort, that they over eat and poison themselves.

Humans too have used Ivy leaves as a medicine for thousands of years; though now-a-days its use is limited to external applications because of unpleasant side effects and its ability to destroy red blood cells if imbibed in excess.   However, externally the leaves still provide a useful herbal poultice for leg ulcers, enlarged glands, painful joints and other pains that can be reached from the outside!

This oak is completely encased in ivy, only the dead branches remain sticking out above the luxuriant growth.

Ivy engulfs its prey - a veteran oak dies

On the ‘Down side’ humans have always grown trees, not only because of their beauty, but also because of their many uses: for food and the energy to cook it; for medicines; for timber with which to make houses, tools, and all the plethora of things that are necessary for a good quality of life; and for ashes to make lye for soap making.  So overall, anything that affects the health of trees qualifies as a devil rather than an angel from the point of view of humans.

But that is not the full story and Ivy too has its uses.  Perhaps the solution is: to remove ivy* from all straight trunked trees and those that are suitable for structural or ornamental timber; then remove it from 25 – 50 percent of the remaining trees.  25% of trees with ivy is quite sufficient in our heavily treed areas e.g. Dorset and Devon; but in areas where trees are more scarce e.g. Northumberland then 50% of the remaining trees with ivy might be acceptable.  Let common sense prevail, and preferably prevent  our non-governmental public bodies and allied groups from removing all our conifers on the grounds that they are not native, or that their English names fail to suggest that they should live south of the border e.g. Scots Pine (Pinus sylvestris) which is prevalent right across Europe from North to South.  To my certain knowledge trees are totally unaware of geographical boundaries – unless they coincide with environmental attributes such as climate, aspect, rainfall and altitude!  However, the conifers do provide very good protection from inclement weather for wildlife and particularly for small birds, many of whom crowded into our group of Lawson Cypresses at dusk on a winters evening, and provided a chirrupy sort of concert for any who cared to stand under and listen!

*Ivy removal is simple.  Pull the small stems off young trees using fingers, before they become established.  For older, thick stems of ivy use a saw, billhook or chopper, to cut and remove a 5cm/2 inch segment from the base of the trunk.  Try to avoid damaging the bark where possible; but a little damage to a small piece of bark is preferable to much the much greater damage caused by the ivy.

Young Penguins in trouble – Why?

April 20, 2011

Reuters recently published an article reporting that only 10% of juvenile Chinstrap and Adélie penguins managed to survive their first journey back to the breeding colonies.  The researchers had concluded that this was due to the effect of warming seas reducing the area of the available ice floes on which the ‘ice algae’ grow (algae growing over the bottoms of floating sea ice); and on which the krill population are said to feed.  However, moulting abnormalities have also been noted in young penguins (New Scientist 16/4/2011 see below); and this effect was first noticed in captive penguins in South Africa – one could presume that they were not short of food, but were almost certainly fed the same food as their free-born relatives fishing for themselves.  This set me thinking of the other possible reasons for the declining numbers of juvenile Chinstrap and Adélie penguins in Antarctic waters.

Some Adélie (Pygoscelis adeliae) Facts:

Adélie penguins stand up to 30 inches (75cms) in height and weigh in at a max. of 5.8kg; these are the penguins with the white circle around each eye.  They arrive at their stony breeding grounds in October/November, and lay one egg which they take turns to incubate; the off-duty parent going out to sea to feed for up to 12 days at a time.  Hatching and fledging completed, they leave with their young in February/March when the chicks are 50 – 60 days old, and spend the rest of the year out on the ice floes.  Some have been found to travel as much as 17,600km over the winter period, and can reach speeds of 45mph in the water!  So they do need a diet that is rich in fat and/or oils.  Their populations have dropped by 65% over the past 25 years.

Some Chinstrap (Pygoscelis antarcticus) Facts:

Chinstrap penguins stand up to 27 inches (68cms) in height and weigh in at a max. of 6kg, although their weight is known to drop to 3kg; their defining characteristic is a thin line of black feathers forming a visual strap from the black back of their head right around their chins.  They prefer stony ground for nesting but will nest on glaciers providing that they can find a few stones for the nest.  Unlike the Adélie penguins, they lay two eggs and the off duty parent only stays away feeding for 6 days at a time.  Apart from this the two species are very similar in their habits, leaving for their winter travels when the chicks are about 60 days old.

Perhaps strangely, I would have suspected that a build up of man-made chemicals (pollutants) are the main culprits for decrease in penguin numbers, rather than marine warming per se.  However, as the oceans absorb more carbon dioxide, another mechanism comes into play.  It maybe that there is a decrease in krill due to increases in the latter.  This would have a knock on effect on the fish population as well as the penguins.

Increased concentrations of these chemicals e.g. DDT (banned in 1972) and PCBs, would affect all levels of the marine food chain and though some authors state that PCBs are not accumulative, I find this hard to believe.  We already know that PCBs have reached the fat deposits of polar bears, seals and even the milk of Inuit women.  We also know that PCBs are insoluble in water, but soluble in fat; therefore it would be strange if they did not accumulate in species at the top of the food chain.  Their levels in fat tissues of mammals have been stated as being in the range of 10 – 0.1μg/gram (Tatsukawa, 1976).  Another study done in the relatively warm Irish Sea by Holdgate (1979) showed levels of <10 – 30μg/kg wet weight in Zooplankton and gave a comparison of the levels found in dead and healthy guillemots. Those that died had 10,000 – 200,000μg/kg in their livers and 1,000 – 10,000μg/kg in the rest of their bodies. The healthy guillemots by comparison had 0 – 2,000μg in their livers and 1,000 – 7,000μg/kg in the rest of their bodies.  I G Simmons, in The Ecology of Natural Resources (1981) noted that:

“In birds, PCBs can affect the metabolic rate and the structure and waterproofing of feathers”.

Obviously this would seriously affect the survival rate of penguins moving from their summer to winter quarters, during which time they are actively trying to build up fat supplies.  Worryingly, the New Scientist magazine of 16 April 2011 reports on an article in Waterbirds, DOI: 10.1675/063.033.0321.  This states that “some young penguins in South Africa and Argentina are not immediately replacing their ‘coats’ after moulting, thus leaving them bald for a time.  The study’s authors think it is probably down to an infection but they have not yet found evidence of a parasite”.  This abnormal moulting behaviour would definitely not favour survival, and could certainly be caused by high levels of PCBs in the body tissues of the young penguins.  A reduction in metabolic rate would greatly exacerbate the problem in conditions of bad weather or lack of suitable food species.

It is interesting to note that most of the studies, relating to PCBs in the marine environment, have been carried out in polar seas.  The following, relating to the Guillemot study, perhaps identifies the reason why fat soluble pollutants are so devastating in the Polar Regions:

“it is hypothesized that the guillemots which were the main victims, were caught at a time of storms and so metabolized PCBs in their fat as well as any which were ingested from their food, leading to the very high levels in their livers”.

Storms are a frequent occurrence in the Antarctic Ocean, so it would not be surprising to find that the penguins were affected in the same way as the guillemots.

The second process that may be affecting the krill populations, concerns higher levels of carbon dioxide in the atmosphere; and these will inevitably lead to higher concentrations in the planet’s water bodies.  In the oceans this reacts with carbonates to form bicarbonates; an action that causes the water to become more acidic and at the same time removes a form of calcium carbonate known as aragonite from the water body.  This is used by molluscs and crustaceans (krill) to form their shells/skeletons and has come to the notice of marine biologists in the context of a potential hazard to our coral reefs, where the concentration of aragonite in the water is critical to the growth of the reef.  According to Bronte Tilbrook (CSIRO, Hobart, Tasmania, Australia) in the New Scientist of 16th April 2011, at an aragonite saturation level of 4.5 the coral grows well, but in areas where the level drops to 2.8, then the coral starts to dissolve.   Even if less likely in the cold waters of the Antarctic ocean, this reaction could still take place, and if it did would certainly affect the survival and growth of the krill population.  Oxygen levels too, are important; and lower levels in the atmosphere, due to combustion of fossil fuels, could cause a reduction of the amount of oxygen dissolving in the water.  This too could have a very damaging effect on both algae and krill, as well as being an extra cause of stress to the fish population.  So the water levels of both carbon dioxide and oxygen could have a knock-on effect on the survival of the penguins; though it is highly unlikely that either is involved with the duration of the moulting process in these penguins.

I am also surprised to find that the researchers consider that penguins, even the Adélie and Chinstrap, are dependent on the krill which are dependent on marine algae.  Although Adélie penguins currently seem to feed mainly on krill; before the early 1800s, when there were large populations of Antarctic Fur Seals and Baleen whales competing for the krill in Antarctic waters, they ate mostly fish and squid.  This was deduced following studies of preserved egg shells at the penguin rookeries.  Therefore, it seems unlikely that if the krill population were to drop, the penguins would not simply return to their old basic and eat more fish and small squid.  However, fish and squid do feed widely on krill (small shrimps and shrimp-like crustacea that are approx. 7% fat and 16% protein) and the krill do feed on the algae, so there could be a knock-on effect if the abundance of algae fell.  But many of the algae in these waters are said to be single celled organisms drifting free in the water column.  It is these and the smaller zoo-plankton that are the main food source for the krill in the diets of both fish and whales’.  Krill numbers would also be affected by the passive uptake of pollutants from the water as they feed, thus affecting the health and survival of their predators further up the food chain.

It is also worth noting that, since we humans have decimated the Baleen whale and Antarctic Fur Seal populations that fed on the krill in large quantities, we have decided that the excess krill might be harvested for human use.  It was said that the productivity of the krill was >50 million t/yr in Antarctic seas and this yield of biomass has been exploited by us in recent decades.  If indeed the penguins’ problems are related to the uptake of pollutants in their food, as hypothesised; one would expect to see some effects with similar problems in the presently recovering Antarctic Fur Seal population.  However, if fish form the greater part of their diet, and pollutants such as PCBs have only reached critical concentrations in krill and small squid, then the seals may be safe for the present.

So in conclusion it would be interesting to know whether Deborah Zabarenko (author of the Reuter’s article) or the Lenfest Ocean Program have measured the PCB concentrations in the livers of any members of the penguin population.  NB the article above does not seem to mention: the finding of any corpses; nor quantitative studies on the populations of free or attached Antarctic algae; nor pollutant concentrations in krill.  Therefore, the conclusions may need some considerable further work before they could be described as an effect that was definitely due to polar ocean warming.  However, it is certainly true that marine warming would result in a harmful stress to this prolific ecosystem; and this could in turn lead to impairment of the metabolic and immune systems of species living in these waters, making them even more susceptible to pollutants.  There is also a need to check for an increase in the acidity of polar seas, in order to be able to rule out the carbon dioxide effect.

For the original Reuter’s article by Deborah Zabarenko, Environment Correspondent

WASHINGTON | Mon Apr 11, 2011 5:27pm EDT, please go to:

Fewer penguins survive warming Antarctic climate

Thoughts on Hugh’s Fish Fight

February 1, 2011

I have just signed Hugh Fearnley-Whittingstall’s petition to stop dead by-catch being thrown back into the sea. But pausing to think about this part of the catch, I realize that there are actually many problems associated with removing it from the marine environment.

Of course the real answer is not to take by-catch; nor to over fill the nets when bringing them to the surface. Having been out on a university research trawler in the 1990s, I am fully aware that the sonar scans and computer information from other boats  mean that the species of fish in a shoal, and its precise size, is known as the trawler approaches the region; and thus well in advance of the net being released in the first place.  Bottom trawls are a very different ‘kettle of fish’.

The number of fish that will die depends on several factors, amongst which, the way that they control buoyancy is probably the most important (see “Buoyancy Matters” end of this note).  Fish that cannot, or are slow to dive are the ones that become prey to the wake hugging gulls.  Those that have lost the ability to control their buoyancy, gradually sink through the water column, becoming dinner for scavengers on their journey to the bottom.  Other fish, krill, copepods and indeed bacteria and algae would normally expect to benefit from the extra nutrients that are thus released into the marine ecosystem – after all most marine organisms live and die in the sea.  If the by-catch came from the sea floor, then providing that they are still alive and don’t get caught by a gull, they don’t usually have swim bladders and will slowly drift down, be reunited with their food source and will survive the experience; though even for them the sudden pressure change may be a problem.  But normally, the ecosystem in which trawled fish live, is sustained by a rich mixed food source that contains some photosynthetic organisms and so moves up and down within the surface layers, stimulated by light and dark at the surface.  For these pelagic fish, it is the speed with which the trawl comes up to the surface and is hauled aboard that is the problem.  If it happened slowly enough most swimbladders could adjust, but too fast and they burst.  They can also become disconcerted when released to the surface and this may help to explain their slowness in swimming back down to their home level.  From the gulls’ point of view, the slower the better; as this allows them to attack the fish in the bag.  From the fishermen’s point of view, the faster the better; as this allows them to get the whole catch on board in an undamaged state – the customers tend to dislike battered fish with speared chunks taken out of their sides!  Arguably the seabirds do not rely on an abundance of fish deposited on the surface by a boat.  This happens naturally when prey species are hunted by faster hunters e.g. tuna who drive the shoals to the surface and coincidentally into the beaks of the gulls.  The only real problem here is that, without the trawler, these fish would probably have lived to see another day and even spawn, before becoming dinner for other marine inhabitants.

Hugh Fearnley-Whittingstall is correct in that it is daft to throw dead fish/sea creatures back into the sea, in terms of human food.  However, if one brings the by-catch ashore, then another very real problem springs to mind, concerning what it is right to do with it i.e.  If the fishermen land this extra catch and sell it, then they are benefitting from the fish that they should not have caught in the first place!  With our huge population, it is difficult enough as it is to maintain fish stocks with enough adult fish, of mature size, to optimise breeding.  I fear that if the fishermen find that they can actually earn an income from the extra catch, then they will do so – after all the human population is now so huge that all that they catch will be eaten.  Unfortunately, the likely result is that even more species of fish and marine organisms will end up on the critical list.

Perhaps the answer is to ensure that any extra catch is taken into custody on the dock and distributed to local fishmongers for the cost of the distribution exercise only.  That would actually have the benefit of providing more jobs for humans, but then of course they would have to be paid out of the sale of the by-catch, with the result that they too would be hoping that the by-catch was as large as possible.  If the fishermen are fined, then they will simply dump the catch at sea as before!

It’s a difficult question.

Buoyancy Matters: Fish in general have a specific gravity of 1.07 and so will tend to sink in water, unless they keep swimming.  This is no problem for predator fish such as mackerel, sharks and indeed rays; but for those that feed in the plankton, neutral buoyancy is an advantage meaning they can stay at the same level as the plankton without having to expend extra energy on maintaining their level in the water column – plankton move up and down according to the light levels.  This neutral buoyancy is achieved by the presence of a swimbladder (air filled bladder) whose pressure can be adjusted to suit the feeding requirements.  Most young fish can adjust the volume of their swim bladders by actually swallowing air from the surface, and in some species this ability is retained in adulthood.  However, in many species of adult fish this duct closes and the volume is adjusted by the removal of gases from the blood.  Since most fish can survive out of water for a short while, provided that they are kept wet and cool; most are returned to the sea alive.  However, whether they will survive or not, depends on the factors mentioned above; plus whether the benthic species can survive the sudden decompression from several atmospheres up to the surface at an air pressure of only 1 atmosphere.  Some fish with swimbladders have been found at depths of over 4000m depth.  For each 10 metres of depth, the pressure increases by 1 atmosphere; so at a feeding depth of 100 metres the water exerts a pressure of 10 atmospheres.  This means that when these pelagic fish surface, the gas in a closed swimbladder expands 10 times and will definitely burst the organ before it reaches the surface.  Even a swimbladder that is connected to the mouth relies on the fish being able to burp out gas fast enough to avoid bursting the swimbladder.  Non-ducted swimbladders are filled with gas from the blood, which implies that their adjustment is normally slight/slow; and big changes in the volume of gas required would take a long time to achieve.

Once on the surface, another problem arises as the fish has to refill its swim bladder adjusting the fill to the increasing pressure as it moves back down.  If only the surface air were available, then obviously as the fish swam down this would be compressed leaving a very deflated swimbladder.  In turn this could cause displacement and abnormal compaction of the internal organs.

Apart from these problems, the swim bladder of some species contains the normal gas mixture of nitrogen, oxygen and carbon dioxide in ratios that differ not only from the air, but also from those in the water at their living depth.  Thus the ratio of nitrogen in a cod’s swimbladder may vary from 7.6% to 56% with associated percentages of oxygen of 76.6% and 30.1%; and carbon dioxide of 15.8% and 13.9%.  All this is managed by a specialized rete mirabile type structure of the supplying blood capillaries – a similar structure is used to cool the blood going to the feet of penguins and to warm the returning blood so that the core temperature is not affected unduly.  Nature is very good at re-using good ideas.

 

Geo-engineering – To use or not to use

October 24, 2010

One of the most topical debates going on at present is on the subject of Geo-engineering.  Should or should it not be used to prevent global warming and if so which methods are most appropriate.

It is certainly true that we humans have historically justified our pollution of the earth on the grounds that “Oh it is only a little drop of ‘Chemical X’ that we are adding to the huge volume of the earth’s oceans/water bodies/atmosphere/soil etc.”  The idea being that the recipient medium is so huge that it really will not make any difference.  Now alas, we know for certain that this is not the case.  Whereas, what goes into the soil is usually broken down sooner or later by the soil’s bacterial cocktail, if it reaches a water body or the atmosphere, the story is very different.  For example:  PCBs (polychlorinated biphenols) turn up in unexpected places, having being concentrated by the oceans’ currents.  They then lodge in fish oils and the fats of marine mammals and the associated human communities.  Once in animal bodies, we do not even now know the full extent of their effects; but we do know that they seem to have a bad effect on the reproductive system.   The chemicals released to our atmosphere, are similarly dissipated and not only travel around the globe in the Trophosphere, but some also seem to affect the gaseous mix in the Stratosphere.

However, I am against Geo-engineering for the following reasons:

Firstly, because the suggested strategies are relatively easy to put in place, but virtually impossible to remove, should the situation swing too far in the other direction.  The need to be able to fully control anything that we do, is not so daft as it may seem.  Already the planet has proved to be unstable in its circa 4.6bn year history.  Geological records and the volcanologists tell us that we are due for a reversal of the magnetic poles; though it was thought that this was a process that would take thousands of years, the latest information suggests that it in the past it has occurred over a mere 4 years!  We know for certain that in the history of life on earth, parts of the planet have been a lot warmer, a lot wetter and a lot colder than they are now.  NB there are huge aquifers under parts of the Sahara and records of predators that could not have survived without large herds of herbivores that in turn could not have survived without grasses and shrubs.  So whatever we do our strategies must be adaptable; and I suggest that we should begin by moving to renewable energy supplies, stop use of fossil fuels unless we are prepared to reconvert the carbon dioxide and water to hydrocarbons, and do what we can to clean up the toxic chemicals that we have released into our oceans and prevent further releases.  The following are my comments on some of the Geo-engineering strategies that have been suggested.

Carbon capture and storage, actually means storage of carbon dioxide (CO2) produced by the process of combustion in our atmosphere.  Thus for every 44gms of CO2 stored we would be removing 32gms of oxygen (O2) from our atmosphere.  Mammals have fairly advanced and efficient lungs but cannot abstract anything like 100% of the O2 inhaled. Invertebrates and Fish etc. are far less efficient and the 20% O2 in our atmosphere is likely to be necessary to provide high enough levels of dissolved Oxygen in the water to support its life forms, especially the Zooplankton.  Storing the carbon on its own would be OK, but better still: why not convert the CO2 back to hydrocarbons or electricity.  A number of research projects are already showing a lot of promise – from solar furnaces to electrochemical cells.

Seeding the ocean with Iron/fertilizers is equally daft.  We already know a lot about the effects of algal blooms due to ‘accidental’ release of fertilizers into the seas and freshwaters of the planet. The increased surface algae die and sink, meanwhile the decomposers get to work and in living remove large amounts of Oxygen from the water; with the result that it becomes too deoxygenated for the survival of the waters fish and their larval stages.

Global warming will, under the normal laws of physics, give rise to higher evaporation rates from the water’s surface.  So there should be no need for the expensive practice of spraying seawater up into the clouds!

The placing of trillions of tiny solar reflectors in space to prevent a percentage of the sunlight from reaching Earth, seems equally fraught.  How are these to be controlled, removed, repositioned etc. We have a complex series of temperature inversions that are not well understood in the atmosphere.  Moving up through the Trophosphere the air cools to well below freezing point at approx 16km up at the equator and 7km at the poles; it then warms up in the Stratosphere until it reaches 0oC at approx the boundary with the Mesosphere at an approximate height of 50km.  However, by the middle of the Mesosphere it has cooled to -90oC, finally warming up to a deep blanket of between 570o – 1570o (night & day and summer & winter temperatures)as it moves up through the Ionosphere, over the next 800 or so kilometres.  I strongly feel that we should not tinker with things that we do not fully understand; just because it seems to be OK if we consider one set of criteria, does not mean that it will be OK if we considered the full as yet unknown set.

Finally, there is the suggestion to release sulphate particles into the stratosphere (approx. 16 – 45km high).  Again, how is it proposed that we control the actual position of these, either around the globe or in terms of their placing in the stratosphere?  What is the chemical effect of placing sulphate particles in our upper atmosphere?  It has been suggested that doing this would be no more damaging than the effect of a large volcanic eruption on the surface of the planet, despite the fact that In general the effects of volcanic eruptions are not welcomed on the surface.  Plus if we are intent on blocking the sunlight, then we also reduce the possibility of power from photovoltaic panels.  This could push the planet towards nuclear power i.e. the use of a very finite resource and one with a very high invisible medical and genetic risk at every stage of its use from mining through to waste storage.  There are simply too many questions that remain unanswered, yet they need to be fully considered by experts in all the branches of scientific knowledge and research, before there is any move to carry out the procedure, or even to trial it.

Please let a wide understanding, of all the mechanisms and needs involved, over-rule uncontrollable geo-engineering and further waste of resources with unknown consequences.  Please let tigergreen.co.uk know how you feel about this topic.  A knee-jerk reaction now could, by chance, have an excellent result, but is more likely to cause a catastrophic reaction either for us or future generations.

Wilderness to Farmlands to Towns – can we afford this change to be inevitable?

October 14, 2010

Wilderness to Farmlands to Towns – can we afford this change to be inevitable?

This topic is often on my mind and it was recently magnified when I read “Among the Elephants” by Iain and Oria Douglas-Hamilton.   Iain’s study sets out to establish how best the African elephant can be managed in the limited areas of the National Parks.  In the final chapter, he comes to the crux of the problem.

Very simply the rapidly increasing human population has resulted in the spread of rural and urban development into areas that were once solely the territory of wildlife and nomadic tribes.  This is actually a worldwide problem; however, this book highlights the problem in Africa.

For millennia elephants have roamed all over Africa from the Mediterranean to the Cape and from East to West. Between 11,000 and 5,000 BC, humans were observing them and they were featured in rock etchings, some of which have been found in Algeria.  Wherever the right mix of grass and trees existed, there too were the elephants.  As they passed, they ate the bark, young branches, fruits and seeds together with grass which they cut with their toe nails i.e. they do not normally pull it up in chunks and if this happens accidentally, they avoid eating the soil and roots. Many of the tree species in particular have seeds that will only germinate if passed through an herbivore’s gut; and since the elephant then deposits the seeds with a liberal amount of dung, the young trees germinate into an ideal growth medium, rather than into the frequently nutrient poor surrounding soil.  When the elephants have opened up an area of woodland so that there is no-longer an ideal mix, and grassland starts to take over, they move on – providing there is the space to do so.  The spreading grassland areas become savannah and can then support vast herds of grazers e.g. the Wildebeest and associated species.  Eventually, droughts and wildfires thin the grass, returning the essential trace elements to the soil, and the grazers turn to a fresh swathe of savannah.  Meanwhile the seeds that have remained dormant in the soil get a chance to germinate, usually in the vicinity of the few remaining trees, and gradually woodland builds up again.  Finally the cycle restarts with the return of the elephants.  In other words, the elephants act just like early humans with their practice of ‘slash and burn’, crop and move on, agriculture.

The problem for elephants now is not that they are hunted by humans per se; it is simply the level of hunting and the restriction of their ancient ranges by human infrastructure.  The African elephant has been hunted, for both ivory, meat and even domestication, for many centuries.  As far back as the 3rd century BC, Ptolemy set up a school for African elephants beside the Red Sea, for the specific purpose of using them with his armies!  However, in those days the population of Africa was very low and scattered, there were none of the huge urban developments and areas of cultivation that exist and are still extending to-day.  This meant that the elephant herds had the run of a whole continent to manage in their own way.

However, from the Douglas-Hamiltons’ book, it is quite clear that even in the Africa of 1975, cultivated crops were being planted right up to the boundaries of the National Parks wherever there was sufficient water for crop growth.  This conflict of land use had been started in past decades by the white settlers, but now that many were leaving, the conflict was being continued to an even greater extent by the ever growing local tribes.  It is an inconvenient fact that if land grows good woodlands, then there is enough water initially for humans to grow good crops.  Where crops can be grown, then towns arise to process them, transport them and provide the necessary infrastructure for a growing non-nomadic culture.  At this point the phrase “enough water initially” becomes crucial.  Inevitably, artesian wells have to be sunk and if water is found then the community continues to grow, if not it eventually moves on.  Unfortunately, the aquifers thus tapped are finite reserves, and their very use may hasten the draw down time for surface waters, thus threatening any remaining surface flows and the wildlife and ecosystems that depend on it.  Where the townships thrive, both the wild animals and indeed the native nomadic tribal peoples become regarded as nuisances; and their lives, harmonious with nature, are restricted to ever smaller areas in the interests of Growth – or should that be Greed.

So, if the change posed in the title is inevitable, then modern humans are faced with yet another dilemma; presuming that they are all agreed that they wish ALL the species on the planet to be able to survive.  Creating a habitat for one species, does not serve the vast mosaic of species that normally co-exist symbiotically.  The best solution is to let wild animals and their vegetation have sufficiently large areas to cycle naturally, in all parts of the globe.  However, this poses the question of how many humans the planet can actually support.  If we and all the other species are to live in harmony, with enough space to be able to enjoy our lives, then we do as individuals need to control our populations.

Traditionally, having long got the better of our carnivorous predators, our population has been controlled by disease and frequent and bloody wars.  However, this latter is a very unpleasant way of behaving and it is to be hoped that diplomacy will always prevail.  But even now, while this happy state of affairs is being established, all national, ethnic and religious groups need to consider how to prevent over population by humans, whilst preserving our varied gene pool and our diversity of thought and culture.  The more numerous we become, the more we encroach on wilderness areas, the scarcer our resources become and the more each diminishing resource costs to use.  In the 1960s water in the UK was still free.  Now we have to pay an ever increasing amount for this commodity so essential to life.  As our population rises so does the cost of living – for how long can we support these increasing costs that actually do nothing to save the species on this planet.

Enter TigerGreen

September 14, 2010

Presently we seem to be faced with some very big changes to the Earth’s status quo, and we need to retain our quality of life.  For one reason or another The Climate is a-changing in ways that we did not expect.  Plus the world’s population has risen from 4.6bn in 1976 to 6.9bn to-day.  If everyone is to be fed and have a good quality of life, then we are all going to have to change the way we do things.

As Alison Tottenham, TigerGreen’s founder, I guess that I should introduce myself briefly.  Soon to reach the age of retirement, I have seen a lot of life and always taken an interest in what is going on.  Having grown up on a working farm I developed a particular interest in the sciences which led to a  BSc (Hons) degree in Agriculture followed after some years by an MSc in Environmental Sciences.  My working life has covered a variety of biological jobs and a full range of work in the Environmental Sciences, plus some work with agriculture.  So I’ve seen a lot to comment on.

All the resources on the Earth are finite, but due to the actions of our Sun and the movement of the planet, we have access to Renewable Energy sources.  One of the best things that we can do right now is to take the pressure off use of fossil hydrocarbons to power our Electricity Grid and  our vehicles.

TigerGreen’s interests lie in all the ways that we can save hydrocarbons and preferably keep them below ground.  Every time that we burn coal, the fossil Carbon combines with Oxygen from our atmosphere forming Carbon dioxide and with Hydrogen to form water.  Even if we could safely bury the Carbon dioxide, for every 12gm of the fossil Carbon that we took out of the atmosphere, we would also be removing 32gm Oxygen – a legitimate and very useful gas – from the atmosphere.  There are better things that we can do with the Carbon dioxide; including use of Solar Energy, with a bit of clever technology, to reconvert it to Hydrocarbons.  Afterall the Plants do this on a daily basis without any help from humans!