Koala extinctions past, present, and future

12 06 2019
Koala

Photo by John Llewelyn

Koalas are one of the most recognised symbols of Australian wildlife. But the tree-living marsupial koala is not doing well throughout much of its range in eastern Australia. Ranging as far north as Cairns in Queensland, to as far west as Kangaroo Island in South Australia, the koala’s biggest threats today are undeniably deforestation, road kill, dog attacks, disease, and climate change.

With increasing drought, heatwaves, and fire intensity and frequency arising from the climate emergency, it is likely that koala populations and habitats will continue to decline throughout most of their current range.

But what was the distribution of koalas before humans arrived in Australia? Were they always a zoological feature of only the eastern regions?

The answer is a resounding ‘no’ — the fossil record reveal a much more complicated story.

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Academics and Indigenous groups unite to stand up for the natural world

26 04 2019
rainforest

Rain forest gives way to pastures in the Brazilian Amazon in Mato Grosso. Photo by Thiago Foresti.

More than 600 scientists from every country in the EU and 300 Brazilian Indigenous groups have come together for the first time. This is because we see a window of opportunity in the ongoing trade negotiations between the EU and Brazil. In a Letter published in Science today, we are asking the EU to stand up for Brazilian Indigenous rights and the natural world. Strong action from the EU is particularly important given Brazil’s recent attempts to dismantle environmental legislation and ‘develop the unproductive Amazon’.

It’s worth clarifying — this isn’t about the EU trying to control Brazil — it’s about making sure our imports aren’t driving violence and deforestation. Foreign white people trying to ‘protect nature’ abroad have a dark and shameful past, where actions done in the name of conservation have led to the eviction of millions of Indigenous people. This has predominantly been to create (what we in the world of conservation would call) ‘protected areas’. The harsh reality is that most protected areas either are or have been ancestral lands of Indigenous people who are closely linked to their land and depend on it for their survival. Clearly, conservationists need to support Indigenous people. This new partnership between European scientists and Brazilian Indigenous groups is doing just that.

Brazil

Brazil’s forest loss 2001-2013 shown in red. Indigenous lands outlined. By Mike Clark; data from GlobalForestWatch.org

In Brazil, many Indigenous groups still have a right to their land. This land is predominantly found in the Amazon rainforest, where close to a million Indigenous people live and depend on a healthy forest. Indigenous people are some of the best protectors of this vast forest, and are crucial to a future of long-term successful conservation. But Brazilian Indigenous groups and local communities are increasingly under attack. Violence on deforestation frontiers in Brazil has spiked this month, with at least 9 people found dead. The future is particularly scary for Indigenous people when there are quotes such as this from the man who is currently the President It’s a shame that the Brazilian cavalry hasn’t been as efficient as the Americans, who exterminated the Indians.

On top of human rights and environmental concerns, there is a strong profit driven case for halting deforestation. For example, ongoing deforestation in the Amazon risks flipping large parts of the rainforest to savanna – posing a serious risk to agricultural productivity, food security, local livelihoods, and the Brazilian economy. Zero-deforestation doesn’t harm agri-business, it allows for its longevity. Read the rest of this entry »





How to improve (South Australia’s) biodiversity prospects

9 04 2019
Fig2

Figure 2 (from the article). Overlaying the South Australia’s Protected Areas boundary data with the Interim Biogeographic Regionalisation for Australia layer indicates that 73.2% of the total protected area (excluding Indigenous Protected Areas) in South Australia lies in the arid biogeographic regions of Great Victoria Desert (21.1%), Channel Country (15.2%), Simpson Strzelecki Dunefields (14.0%), Nullarbor (9.8%), Stony Plains (6.6%), Gawler (6.0%), and Hampton (0.5%). The total biogeographic-region area covered by the remaining Conservation Reserves amounts to 26.2%. Background blue shading indicates relative average annual rainfall.

If you read CB.com regularly, you’ll know that late last year I blogged about the South Australia 2108 State of the Environment Report for which I was commissioned to write an ‘overview‘ of the State’s terrestrial biodiversity.

At the time I whinged that not many people seemed to take notice (something I should be used to by now in the age of extremism and not giving a tinker’s about the future health of the planet — but I digress), but it seems that quietly, quietly, at least people with some policy influence here are starting to listen.

Not satisfied with merely having my report sit on the virtual shelves at the SA Environment Protection Authority, I decided that I should probably flesh out the report and turn it into a full, peer-reviewed article.

Well, I’ve just done that, with the article now published online in Rethinking Ecology as a Perspective paper.

The paper is chock-a-block with all the same sorts of points I covered last year, but there’s a lot more, and it’s also a lot better referenced and logically sequenced.

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A call to wings

19 03 2019

This week sees the launch of an updated bat synopsis from Conservation Evidence, adding new studies that have come out since the first synopsis was published in 2013.

The synopsis collects and summarises studies that test conservation actions such as ‘provide bat boxes for roosting bats’, and organises the studies by the action that they test. This focus on solutions makes it a handy point of reference for conservationists wishing to see what might work — and what is unlikely to work — to conserve bats.

Bechstein’s bat – photo credit Claire Wordley

Bechstein’s bat (Myotis bechsteinii) — photo credit Claire Wordley

 

Free to read or download from Conservation Evidence, the update represents a major addition to the original, containing 173 studies to the original 101. Studies are included if they tested an action that could be put in place for conservation, and measured an outcome for bats. As well as adding studies published from 2013 on, the update adds studies originally published in Spanish or Portuguese, and it is hoped that more languages will be added in future editions. Read the rest of this entry »





Thirsty forests

1 02 2019

Climate change is one ingredient of a cocktail of factors driving the ongoing destruction of pristine forests on Earth. We here highlight the main physiological challenges trees must face to deal with increasing drought and heat.

Forests experiencing embolism after a hot drought. The upper-left pic shows Scots (Pinus sylvestris) and black (P. nigra) pines in Montaña de Salvador (Espuñola, Barcelona, Spain) during a hot Autumn in 2015 favouring a massive infestation by pine processionary caterpillars (Thaumetopoea pityocampa) and tree mortality the following year (Lluís Brotons/CSIC in InForest-CREAF-CTFC). To the right, an individual holm oak (Quercus ilex) bearing necrotic branches in Plasencia (Extremadura, Spain) during extreme climates from 2016 to 2017, impacting more than a third of the local oak forests (Alicia Forner/CSIC). The lower-left pic shows widespread die-off of trembling aspen (Populus tremuloides) from ‘Aspen Parkland’ (Saskatchewan, Canada) in 2004 following extreme climates in western North America from 2001 to 2002 (Mike Michaelian/Canadian Forest Service). To the right, several dead aspens near Mancos (Colorado, USA) where the same events hit forests up to one-century old (William Anderegg).

A common scene when we return from a long trip overseas is to find our indoor plants wilting if no one has watered them in our absence. But … what does a thirsty plant experience internally?

Like animals, plants have their own circulatory system and a kind of plant blood known as sap. Unlike the phloem (peripheral tissue underneath the bark of trunks and branches, and made up of arteries layered by live cells that transport sap laden with the products of photosynthesis, along with hormones and minerals — see videos here and here), the xylem is a network of conduits flanked by dead cells that transport water from the roots to the leaves through the core of the trunk of a tree (see animation here). They are like the pipes of a building within which small pressure differences make water move from a collective reservoir to every neighbours’ kitchen tap.

Water relations in tree physiology have been subject to a wealth of research in the last half a decade due to the ongoing die-off of trees in all continents in response to episodes of drought associated with temperature extremes, which are gradually becoming more frequent and lasting longer at a planetary scale (1). 

Embolised trees

During a hot drought, trees must cope with a sequence of two major physiological challenges (2, 3, 4). More heat and less internal water increase sap tension within the xylem and force trees to close their stomata (5). Stomata are small holes scattered over the green parts of a plant through which gas and water exchanges take place. Closing stomata means that a tree is able to reduce water losses by transpiration by two to three orders of magnitude. However, this happens at the expense of halting photosynthesis, because the main photosynthetic substrate, carbon dioxide (CO2), uses the same path as water vapour to enter and leave the tissues of a tree.

If drought and heat persist, sap tension reaches a threshold leading to cavitation or formation of air bubbles (6). Those bubbles block the conduits of the xylem such that a severe cavitation will ultimately cause overall hydraulic failure. Under those conditions, the sap does not flow, many parts of the tree dry out gradually, structural tissues loose turgor and functionality, and their cells end up dying. Thus, the aerial photographs showing a leafy blanket of forest canopies profusely coloured with greys and yellows are in fact capturing a Dantesque situation: trees in photosynthetic arrest suffering from embolism (the plant counterpart of a blood clot leading to brain, heart or pulmonary infarction), which affects the peripheral parts of the trees in the first place (forest dieback).

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We need a Revegetation Council

14 01 2019
planting trees

As I have discussed before, the greatest threatening process to biodiversity in South Australia today is past and ongoing clearing of native vegetation. So, arresting further vegetation clearing, and restoring previously cleared land to functional native-vegetation communities are easily the highest priorities across the entire State.

Despite some valiant attempts across South Australia to revegetate previously cleared areas1, the haphazard approach to reforestation in South Australia means that we are unlikely to be maximising ecological function and providing the best habitats for native biodiversity. Several improvements in this regard can be made:

(i) Establish a State Register of past, ongoing, and planned revegetation projects, including data on the proponents, area revegetated, species planted, number of individuals planted for each species, monitoring in place (e.g., plant survival, other species using the restored habitat, etc.), and costs (actual or projected). Such a State Register would allow for a more regional coordination of future revegetation projects to suggest potentially more ecologically useful approaches. This could include identifying the most locally suitable species to plant, maximising the area of existing native habitat or restored fragments by planting adjacent to these, joining isolated islands of habitat to increase connectivity, or even to create more efficient projects by combining otherwise independent proponents (e.g., adjacent landholders).

(ii) Establish a State Revegetation Council that uses data from the Register to prioritise projects, enhance collaboration, and suggest improvements in design and placement according to the principles mentioned above. The Council could also help to coordinate monitoring of progress and ecological outcomes at the landscape scale. A similar State Register for Wetland Restoration and a relevant Council could be established in a similar manner, emphasising the conservation and restoration of smaller wetlands with more unique, endemic plant species. Likewise, both Councils could ideally assist in coordinating non-profit and private organisations in terms of their revegetation priorities, as well as coordinate with conservation covenants(see below) for private landholders.

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Influential conservation ecology papers of 2018

17 12 2018

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For the last five years I’ve published a retrospective list of the ‘top’ 20 influential papers of the year as assessed by experts in F1000 Prime — so, I’m doing so again for 2018 (interesting side note: six of the twenty papers highlighted here for 2018 appear in Science magazine). See previous years’ posts here: 2017, 20162015, 2014, and 2013.

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