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Daily Archives for July 2, 2019
Africa – Reefs
Dolphin researchers say NZ’s proposed protection plan is flawed and misleading
Flickr/Scott Thompson, CC BY-ND
Elisabeth Slooten, University of Otago and Steve Dawson, University of Otago
The New Zealand government recently proposed a plan to manage what it considers to be threats to Hector’s dolphins, an endemic species found only in coastal waters. This includes the North Island subspecies Māui dolphin.
Māui dolphins are critically endangered and Hector’s dolphins are endangered. With only an estimated 57 Māui dolphins left, they are literally teetering on the edge of extinction. The population of Hector’s dolphins has declined from 30,000-50,000 to 10,000-15,000 over the past four decades.
The Ministry for Primary Industries (MPI) and the Department of Conservation (DOC) released a discussion document which includes a complex range of options aimed at improving protection.
But the proposals reveal two important issues – flawed science and management.
Read more:
Despite its green image, NZ has world’s highest proportion of species at risk
Flawed science
Several problems combine to overestimate the importance of disease and underestimate the importance of bycatch in fishing nets. For many years, MPI and the fishing industry have argued that diseases like toxoplasmosis and brucellosis are the main cause of decline in dolphin populations. This is not shared by New Zealand and international experts, who have been highly sceptical of the evidence. Either way, it is not an argument to ignore dolphin deaths in fishing nets.
Three international experts from the US, UK and Canada examined MPI’s work. They concluded that it is not possible to estimate the number of dolphin deaths from disease, much less claim that this impact is more serious than bycatch. On the other hand, it is easy to obtain an accurate estimate of the number of dolphins dying in fishing nets, as long as enough observers are allocated. MPI has failed to do so. Coverage has been so low that MPI’s estimate of catch rates in trawl fisheries is based on one observed capture.
Supplied, CC BY-ND
The MPI model used in the public discussion document (and described in more detail in supporting materials) is complex, and a one-off. It is based on a “habitat model” of dolphin distribution, but fits actual dolphin sightings poorly.
Another problematic aspect of the method is that there is no clear time frame for the “recovery” of dolphin populations to the specified 90% of the unimpacted population size for Hector’s dolphins and 95% for Maui dolphins. This is one of the first things any decision maker would want to know. Would Māui dolphins be held at the current critically endangered population level for another 50 years? If so, this dramatically increases their chance of extinction.
Flawed management options
The second set of problems concerns the management options themselves. These are a complex mix of regulations that differ from one area to another, for gillnets and trawling. They frankly don’t make sense. The International Whaling Commission (IWC) and International Union for Conservation of Nature (IUCN) have recommended banning gillnet and trawl fisheries throughout Māui and Hector’s habitats. MPI’s best option for Māui dolphins comes close to this in the middle of the dolphins’ range, but doesn’t go as far offshore in the southern part of their range.
The South Island options for Hector’s dolphin are much worse. MPI’s approach has been to try to reduce the total number of dolphins killed to just below the level they believe is sustainable. MPI has invented its own method for calculating a sustainable number of dolphin deaths, which is much higher than the well-tested method used in the United States. The next step has been to find areas where the greatest number of deaths can be avoided at the least cost to the fishing industry.
Supplied, CC BY-ND
This sounds reasonable, but fixing the problem only in the places where the largest number of dolphins is being killed will have several negative consequences. Experience shows that fishing effort shifts beyond protected areas, merely moving the problem.
For example, MPI’s proposals leave a large gap on the south and east side of Banks Peninsula, in prime dolphin habitat. If the nearby areas are protected, this gap will be fished, and dolphin bycatch will continue unabated. What’s needed is protection of the areas where dolphins live.
MPI’s focus on reducing the total number of dolphin deaths also ignores the fact that it really matters where those deaths occur. Several Hector’s dolphin populations in the South Island are as small, or smaller, than the Māui dolphin population.
Entanglement deaths have much worse consequences in such small populations, which form a bridge between larger populations. Yet they get no attention in the current options. MPI’s proposals would lead to the depletion of small populations, with increased fragmentation and extinction of local populations.
Only one option
If we want to ensure the long-term survival of these dolphins, there is only one realistic solution: to remove fishing methods that kill dolphins from dolphin habitat. The simple solution is to use only dolphin-safe fishing methods in all waters less than 100 metres deep. This means no gillnets or trawling in harbours and other coastal waters up to the 100 metre depth contour.
There is no need to ban recreational or commercial fishing, but we must make the transition to selective, sustainable fishing methods. These include fish traps, longlines and other hook and line methods. Selective, sustainable fishing methods also use less fuel than trawling and avoid impacts of trawling and gillnets on the broader marine environment.
We also need more observers and more cameras on fishing boats. MPI’s estimate of how many dolphins are dying in fishing nets is almost certainly an under-estimate. It depends heavily on assumptions that are not supported by data.
With observers on only about 2-3% of the inshore fishing boats, the chances of missing bycatch altogether is very high. Low observer coverage also means boats can fish differently on the days when they have an observer aboard (for example, avoiding areas where they have caught dolphins).
Supplied, CC BY-ND
We know what works
Despite getting a poor report card from the international expert panel, MPI presented a virtually unmodified analysis to the IWC’s scientific committee last month. The committee identified most of the same issues and concluded it needed more time to decide whether MPI’s approach is fit for purpose. Meanwhile the IWC reiterated its recommendation, which it has been making for eight years, to ban gillnets and trawl fisheries throughout Māui dolphin habitat.
In the meantime, dolphins continue to be killed in fishing. We need to make decisions on the basis of scientific evidence available now. All of the population surveys, including those funded by MPI, show Hector’s and Māui dolphins live in waters less than 100 metres deep.
The best evidence of what works comes from Banks Peninsula, where the dolphins have had partial protection since 1988, and detailed follow-up research. This population was declining at 6% per year before gillnets were banned to four nautical miles offshore and trawling to two nautical miles. Even though there was no management of disease, the rate of population decline has dropped dramatically to less than 1% per year. If disease were a serious problem, the restrictions on gillnets would have made little difference.
A general principle in conservation is that the longer you wait, the more difficult and more expensive it will be to save a species, and the more likely we are to fail.
Elisabeth Slooten, Professor, University of Otago and Steve Dawson, Professor, University of Otago
This article is republished from The Conversation under a Creative Commons license. Read the original article.
White cedar is a rare bird: a winter deciduous Australian tree
Scamperdale/Flickr, CC BY-SA
Gregory Moore, University of Melbourne
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White cedar (Melia azedarach) grows naturally across Queensland and northern New South Wales, but is widely planted as an ornamental tree all over Australia. It also grows across much of Asia, and belongs to the mahogany family.
This wide dispersal sees the species given a very wide and diverse range of common names, including: umbrella cedar, pride of India, Indian lilac, Persian lilac, and Chinaberry. It Australia it is known as white cedar due to its soft general-purpose timber.
The name Melia was the Greek name given to the ash tree, which has similar foliage, and azedarach means “poisonous tree” – parts of it are toxic.
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White cedar is something of a rarity among Australian native trees, as it loses its leaves in winter or early autumn. Winter deciduous trees are highly valued in landscape design as they provide all the benefits of summer shade, but allow winter light.
The Conversation
While Australia has an abundance of evergreen tree species and a variety of summer deciduous trees that lose their leaves in summer when water is scarce, we have few winter deciduous native trees. White cedar fits the bill beautifully, and despite a few shortcomings has some very attractive traits.
White cedar is usually a small spreading tree with a rounded canopy up to about 6m in height, but under the right conditions trees can be more than 20m tall, with a canopy spread of 10m or more. They have quite dense foliage composed of dark compound leaves up to 500mm long, which transition from dark green to a pale yellow in autumn.
As a winter deciduous tree they are a very popular native tree that has been widely planted as street trees and in domestic gardens, where specimens of 10-12m are common. The trees are often considered to be short-lived (around 20 years), but in gardens and where irrigation is available some may live for 40 years or longer.
Good specimens of white cedar have many small flowers (20mm) that are white with purple/blue stripes and a wonderful, almost citrus-like scent. The fruits are about 15mm in diameter and bright orange in colour. They are usually retained over winter and so the trees provide a seasonal smorgasbord – shade in summer, autumn foliage colour, orange fruits in winter, and attractive scented flowers in spring.
Many specimens are prolific in their production of fruits and seeds, which readily germinate, underscoring the weed potential of the species under the right circumstances. They can be an invasive species in some parts of Asia and Africa.
Unfortunately as the fruits mature and dry they become as hard as ball bearings. If you mow over them they can fire from under a mower like bullets, and if they land on a hard paved surface they can be a tripping hazard for people who unexpectedly find themselves skating. The fruits and foliage can also be quite toxic if eaten. So this would appear to put a bit a dampener on the use of the tree. However, in recent years non-fruiting varieties of white cedar have become available and these have proven popular as street and garden trees.
A toxic treat
Many parts of the tree are toxic – interestingly, though, not the fleshy part of the fruit. It has evolved to be attractive to the birds that disperse seed. However the seeds are very poisonous, and as few as 6 or 8 seeds can be fatal for children. Fortunately, the seeds are very hard and do not taste very pleasant, so the risk of humans eating them is quite low.
Despite this, white cedar has been widely used as a medicinal plant by indigenous cultures, especially for intestinal parasites. The seeds have been widely used to make beads by indigenous peoples in Asia and Australia, and in some places the tree is called the bead tree.
An easy grower
One of the good things about white cedar is they are easily grown, and cope quite well with the low rainfall in many parts of Australia. They also tolerate a variety of soil types, which is why they have been so widely and successfully spread.
The trees are quite resistant to termite damage and their poison does protect them from grazing mammals and some insects. They can be prone to root problems and it is not uncommon for their trunks to break off at ground level, especially if they have been poorly propagated or planted, which can be a big problem when they are planted as a street tree.
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Although they are related to mahogany, their wood can be quite brittle and easily broken, which means care should be taken when pruning or working on them. When the wood dries it shatters easily and can send shards in all directions when you try to snap it. In Australia the wood can range from light cream to dark brown in colour, and while it is quite a useful wood for carving and furniture, it is not widely used.
As a winter deciduous native tree of smallish stature, with many attractive characteristics, the white cedar really is an Australian rarity, despite how widely it occurs or is planted.
Gregory Moore, Doctor of Botany, University of Melbourne
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Academia can help humans and large carnivores coexist
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Euan Ritchie, Deakin University; Abi Vanak, University of KwaZulu-Natal; Benjamin Scheele, Australian National University; Laurentiu Rozylowicz, and Tibor Hartel
Bears, wolves, lions and other top predators have a long history of conflict with people – they can threaten our safety and kill livestock.
In our recent study, published in Conservation Biology, we outline how conventional conservation approaches are unlikely to lead to effective coexistence between humans and large carnivores in human-dominated landscapes.
Read more:
Guardian dogs, fencing, and ‘fladry’ protect livestock from carnivores
This wicked problem encompasses public safety, agriculture, conservation, animal welfare, and more. Each facet is commonly managed by a different institution working in isolation – often failing to reflect the reality of our highly connected world.
Academia can help foster better institutional arrangements, especially in places like Romania, India and Brazil, where there are substantial populations of people and large carnivores in shared spaces.
In Romania, for instance, bears and wolves live in the same places used by shepherds and their livestock. Guardian dogs typically help protect livestock from being attacked.
Similarly, Australia’s own dingo occurs across agricultural and pastoral regions, with sentiments ranging from protected native species to disliked pest.
Why institutions fail carnivore-human relationships
From bears in Romania to dingoes in Australia, large carnivores are found in an array of places. This means they regularly affect the interests of a range of institutions, from agriculture to forestry.
But the current arrangements are poorly suited to facilitate a peaceful coexistence between humans and large carnivores.
Typically, institutions focus on a small subset of concerns. Forestry and agricultural sectors, for instance, may not feel responsible for large carnivore conservation because they are primarily interested in timber and agricultural production.
On the other hand, institutions for transport, energy and border security might be indifferent towards large carnivores. But they can negatively affect these animals if they put up barriers restricting predator movement and inappropriately handle roadkill.
These compartmentalised, and often conflicting, institutions are poorly suited to helping wildlife, especially when large carnivores, such as leopards, wolves and bears, live in human-dominated regions.
A role for academia
Academia has solutions to offer.
Most environment-related professionals, like foresters, wildlife managers and conservation biologists, are trained in a range of academic institutions. Unfortunately, they are often taught narrowly within their sector or discipline.
However, all these future professionals passing through the same institutions provides a great opportunity for a broad change in how we approach difficult conservation challenges and conflict with wildlife.
Photo credit: John Linnell
There are at least three ways in which academia could help address the challenges of human and large carnivore coexistence:
1. Break down the silos
Academic institutions need to create special centres to better support teaching and research across different disciplines.
Conservation – and, on a broader level, how humans should relate to the natural world – cannot be siloed away in wildlife management courses.
2. Broaden the view
We need to actively foster a broader perspective that does not see large carnivores as an “enemy”, while still safeguarding human life. This is a complex and multifaceted challenge.
By working across disciplines, universities have the chance to actively foster this broader perspective. This may seem like a nebulous point, but the collapse of species around the world has highlighted how ineffective our current approach to conservation is. We need to move beyond tinkering around the edges of our extinction crisis.
Conservation policy is already equipped to address individual targets such as regulating carnivore populations and legally protecting species. It is the larger aim of changing norms, challenging values and ensuring all these various institutions are pulling in the same direction that we need to tackle – a tactic called the “leverage points approach”.
3. Work outside the academy
Academia could support existing collaborations. When people with shared interests come together to pool knowledge and address a particular issue, we call it a community of practice. Academia can contribute to these communities by offering the skills and expertise of its graduates, but also broader social and industry connections (where required), knowledge sharing, collaborative research, education and technological innovation.
We need big carnivores and they need us
Large carnivores are critical for the health of ecosystems globally, and we need to provide them with enough space and tolerance to survive.
The ongoing controversy regarding the management of the dingo, Australia’s largest land-based predator (aside from humans), provides a perfect test case for this new approach to managing human-wildlife conflict.
If we can achieve more harmonious relations with the world’s top predators, many of the myriad other species that coexist with them are also likely to benefit from both better habitat management and conservation and the important ecological effects large carnivores can have, such as keeping herbivore and smaller predator numbers in check. This can be a positive step towards addressing Earth’s mass extinction crisis.
The authors would like to thank John Linnell, Senior Research Scientist at the Norwegian Institute for Nature Research, for his contribution to this article.
Euan Ritchie, Associate Professor in Wildlife Ecology and Conservation, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University; Abi Vanak, , University of KwaZulu-Natal; Benjamin Scheele, Research Fellow in Ecology, Australian National University; Laurentiu Rozylowicz, Center for Environmental Research and Impact Studies, University of Bucharest, and Tibor Hartel, Invited user
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Kevin's Walk on the Wild Side 