Showing posts with label habitat. Show all posts
Showing posts with label habitat. Show all posts

Wednesday, 2 December 2015

Species'ism

Is it ok to be species'ist - to advance one species or retard another just because of its species?

We seem to have concluded that racism and sexism - advancing or retarding individuals just because of their race or gender - is not ok. But what about whole species?

Species'ism seems to happen a lot in nature. In fact, a colleague and I recently found that one species of tree has been comprehensively retarded over 2,000 square kilometres of the Cooma-Monaro plains of southern NSW. Every individual Eucalyptus viminalis - Ribbon Gum - is either dead or dying in this extensive area. The Ribbon Gum was an iconic tree of this region, common on the rocky knolls and hills around fertile grazing and farming land. You can still see healthy trees in the region ...but if it is healthy it is not a Ribbon Gum.

We don't know why this one species is dying while the snow gums and other trees around are not. We do know insects are involved, but they are not the sole or even primary cause. We suspect that drought or changes to the rainfall patterns or to minimum and maximum temperature regimes might be affecting this one species to a much greater extent than others. There may even be some impact on this one species caused by changes in the local fire regime - too few, or too hot, or just too different to the pre-European fires. We do know that the once extensive stands of Ribbon Gum are all dead. We know this species won't be coming back at least for quite some time if ever. Nature, or the heavens, or even climate change has practiced species'ism to a fatal extent here.

We also know that something else will take over the place these trees previously occupied - something else will use the sun, the water and the nutrients that those Ribbon Gums used to use. Do we care what takes over? Do we want to promote one species over another? Should we actively intervene by planting our preferred species or be passive and just let any local "disturbance adapted" species win this 2,000 square kilometre home?

If a species that we do not want takes over this land, we define it as a "weed" and happily practice species'ism. But why should we choose not to want a species that can grow where Ribbon Gum clearly can no longer survive? The reasons for species'ism vary from the new species not providing the ecological services we are used to, through to aesthetics, and even that the new species are just "not from around here".

All trees provide a range of ecological services to different extents. They all produce oxygen, they all sequester carbon, they all slow and filter water. Some trees are more preferred as the habitat of birds or aerborial mammals while others are better at sheltering ground and bark dwelling insects. Some do more while some do less, but none will do exactly what a stand of Ribbon Gum used to do.

Aesthetics too are confusing. Humans tend to like what they are used to, and they have been used to Ribbon Gums in these lands. Although these trees have been dying for a decade now, so maybe the humans travelling through this region think dead trees are attractive!

Like racism, the argument that species are just "not from around here" is very often the only reason given for Species'ism. Often passionate arguments are made that only local species, grown from locally collected seeds should be planted in any restoration or revegetation project. But, the local Ribbon Gum will no longer survive. So, do we plant Ribbon Gum from areas far away that might cope with whatever killed the current trees - the natural range for Ribbon Gum is extensive and goes from Tasmania through Victoria and up the coast of NSW and someone could probably trial a huge selection if there was time. Does that violate the "not from around here" bias? But if we don't really know what killed the current Ribbon Gum, how could we really risk planting more Ribbon Gums? Is a Ribbon Gum grown from a seed collected in Tasmania more "local" than seed from another species of Eucalyptus grown only 10's or 100's of kilometres away from the dead Monaro plains? How important is it that the species remains "pure"?

How do we value the trees and their ecosystems services and aesthetics? How do we balance our understanding of the history or iconic nature of one species with the risk its time has come! How do we choose between species? These are not simple questions and they can't be answered by by scientists or economists or conservationists or engineers or community activists or even artists working alone.

 

Sunday, 21 June 2015

800 year celebration

This year, many are celebrating the 800'th year anniversary of the Magna Carta. While many claim this is the start of modern Law (at least, the British sort), it was a 'win' for the Barons over the King: the King was now answerable to the Law and the Barons, and not 'just' to God at The Day of Final Judgement. Actually a lot of merchants won too - it was their assistance that resulted in the Barons getting the upper hand, so they were rewarded.
But the document that was signed (or for the pedant, sealed) 800 years ago offered a lot for the struggling peasant too. So much in fact, that many of these benefits for the peasants were separated from the "Great Charter" into a companion document called the "Charter of the Forest". The forests were vital for the peasants - they used its resources for energy (fire wood); grazing; fodder; collecting food like berries and mushrooms; and building. Access to the forest could even be thought of as a medieval version of the dole - if you had no home and no family support, you could meet the minimum of your needs from the forest. But the Kings had been progressively alienating the peasants from their forests and claiming more and more to the sole use of the sovereign. Robin Hood was famous for killing the foresters who were enforcing the King's rules as much as for his giving stollen goods to the poor! The Charter of the Forests returned to the users of the forest their rights of agistment, estover, pannage and turbury (or rights to graze sheep, pasture pigs, collect firewood and cut turf). A recent study showed that peasant and small family groups can continue to exercise these right for generations without destroying the forest.
Collecting sticks in a public forest. Firewood, shelters or just a game?

So, how are things today 800 years after the The Great and The Forest Charters were sealed? Well, the Law is firmly established with respected and noble traditions. The Barons have changed from being owners of vast tracks of land to being owners of vast mineral reserves and coal deposits, or chains of factories, newspaper and entertainment services, while the merchant class still funds the changes in the modern world. But the peasants or the free men and women (in our modern parlance - the taxpayers and the struggling mums and dads) do not appear to have been able to take up their benefits from forests. In some states of Australia, over 50% of the forests are reserved for the sovereign (government) and the peasants may only look, or if they are young and fit, walk but not touch. Modern-day Barons may take timber or graze industrial scale flocks of cattle or even mine in the rest of the forest, but individual peasants can't remove or use anything to meet their personal or family needs. In fact, there is increasing pressure to keep peasants and people of all sorts away from the forests altogether - keep them corralled in articifial castles cut off from the outside world.
Has the Charter of the Forest ever been repealed? Is it too late to exercise the right to take the forests back from the Barons and the Government? The peasants and free men and woman of the modern world cannot live in the forests full time any more, but they can reconnect to their heritage and their nature if they occasionally exercise their right to collect a bit of fire wood for themselves and maybe BBQ a meal or two. We should certainly have as much right to that as we do to receiving the dole. Might be cheaper and healthier for everyone too.
So, this year, celebrate the Magna Carta with a walk through your forest.
A medieval forest, from Livre de chasse (1387) by Gaston III, Count of Foix.



Wednesday, 27 May 2015

Reserving a big new National Park

If the current reserve system in Victoria - both formal and informal - cannot save Leadbeater's Possum, why would just adding area to the formal reserve system will make a positive difference?

A substantial increase in the formal area of reserve in Victoria, by itself, would not "save" the possum. At the very least, such an increase would need to occur in conjunction with an even more substantial increase in funding and resources to offer a chance of success. It is myth that National Parks can simply be locked up and left to follow healthy and sustainable trends. In cases where reserves have been simply fenced in, the ecosystems often drift off to something unexpected and undesirable as the result of altered fire or flood regimes, or invasive species, or a combination of factors. Active management, resource intensive management, will be increasingly needed for our existing reserves to "save" species in the face of ecological change wrought by climate change and other human impacts. Extension of the reserve boundaries will have to consider active management and substantial increases in funding. No doubt this will be an uncomfortable debate for many people, but one that is needed.

These extra resources won't be just for an extension of the track system, or better maintenance of fire trails, or better rubbish removal, or even more research that describes the current populations. In the specific case of Leadbetter's possum, if the lack of habitat hollows is already a population threatening problem, and hollows are not being formed naturally at a sufficiently fast rate, then active management will be necessary to correct this imbalance - just waiting another 70 years and hoping everything survives that long is not a recipe for success. The predominant factor relating to hollow development is tree size, and Foresters especially trained in silviculture and forest ecology, know how to manipulate population pressures within a forest to ensure a minimum number of trees can grow to reach the size to support hollow development in the minimum amount of time. Further, they can appropriately "damage" the crown of appropriate trees to speed up hollow development. The wait for hollows to home the possum can be substantially reduced from 70 years with active management. But such an exercise is expensive, labour intensive and will require some trees to be felled.

An even greater problem for under-resourced reserves is that weeds will take natural advantage of increased stress caused by changes in fire regimes or climate. Similarly, pest populations will boom as natural control mechanisms falter under already observed changes. How will the existing reserve system cope if Australia suffers a pest outbreak like the mountain pine beetle experienced in Canada? What happens to the potential for control or mitigation if the reserve system is twice as large due to an under funded increase in area? Active management was seen as an essential part of coping with this pine beetle outbreak with the Canadian Government providing substantial funding to First Nations, communities and school districts for fuel management and hazard tree removal in post-infested areas, as well as recovering some costs by selling the killed timber.

Changed fire regimes in the US have changed the species composition and structure of the forests leading to more mega fires than ever before. Active management is being pursued in the U.S., and products are being sold to offset some of the costs of management. United States taxpayers are fully funding their program but American Professor Scott Stephens said about 40 per cent of the cost of implementing the program is covered by repurposing the cleared timber (i.e. selling it as garden mulch, woodchip, fence posts of even sawn lumber).

An increasing concern is that Eucalypts have particularly poor dispersal capabilities, so natural stands will be generally be unable to track changing climatic conditions. (Booth et al, 2015). Will active management be needed to translocate species to new environments? Species like the "pioneer" Eucalyptus that dominate after a fire, need bare ground at least 80 m from standing dominant trees for their seeds to germinate and grow well. However, if the climate warms and the rainfall patterns change as predicted in many reputable Australian climate models, will these large gaps of bare earth may become too hot and dry for successful natural regeneration? Will reserve workers need to manually plant and water seedlings to avoid a species change?

More money and resources need to be allocated to the existing Reserves and National Parks to give a chance to "save" what humans hold precious. Substantially more funding will be required if the area of reserves increases - there is little opportunity for "economies of scale" in the reserve system management because each additional hectare added is unique. Without a substantial increase in general tax payer funding the reserve managers need opportunities to co-fund their own maintenance and safe keeping. Payments for ecosystem services have long been held out as a way of generating these sorts of funds, but the mechanisms for such funding are far from developed and active. Sale of products extracted from the reserves, especially when the mass of those products may themselves be contributing to the problem, is a much more immediate source for funding.

 

Saturday, 21 February 2015

Arboreal habitat

What could be nicer than seeing a pigmy possum or beautiful bird curled up in a nest, high in a hollow in a tree? But, isn't it a good thing trees don't whimper.



How would we enjoy watching all those birds and cute animals snuggled in their tree hollow nests if we also heard the trees crying over their wounds? Trees that stand proud with thick protective bark defending against damage do not provide the hollows for colourful birds. Trees that stand tall with branches still limber enough to defy gravity without breaking do not provide the nests for our cute arboreal mammals. Insects and spiders may shelter in the fissures of bark, but as far as a house for those birds and animals, such healthy and strong trees are worthless.

Hollows for nests are formed when the defensive shield is breached and the inner wood exposed. Trees will fight to seal the breach with kino, gum or resin, but when decay fungi or insects get a breach head established then the rot sets in (literally). Unfortunately, the rot doesn't stop when a cavity big enough for a nest is created - the decay can extend into the very Heartwood of the tree and ultimately lead to its collapse.

A tree that could manage to never suffer the loss of a branch or a wound in its defensive shield of bark might actually live forever. It would look majestic too, at least to the humans it would tower above. But it would not provide a home for many birds and animals. 

Foresters of the 1940's, 50's and 60's thought their job was to grow majestic trees. They cleared away the wounded trees that had lost the fight against rot and damage. They ensured the offsprings of those trees had room to soar without breaking themselves against older neighbouring trees. They kept the fires away or allowed them to burn so cool that the bark barriers were not breached. The trees grew: healthy and undamaged. But increasingly now we realise that they also grew without the hollows. In Victoria, the possum emblem of the State is increasingly homeless as the trees with hollows collapse when their hearts rot away but the new generation stays too solid. 

Do we need now to wound these majestic trees to make the homes for our cutest animals? Should the foresters of the 1900's have been more careless and ensured trees were damaged to help ensure future habitat for birds and animals? Or did they do the right thing and expect only to make future homes for humans out of a half century of healthily growing trees?