fisheries | ConservationBytes.com

Big sharks. Big mystery.

9 03 2011

My PhD student, Ana Sequeira, has just written a great little guest blog post for the Environment Institute‘s blog. Given I’m en route to Tasmania for a quick consultancy meeting, I thought I’d let myself off the hook and reproduce the post here. Well done, Ana (and hint to my other students – your time on ConservationBytes.com is coming…).

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This week is Seaweek and guest blogger Ana Sequeira describes how whale shark distribution might be shifting according to seasonal environmental predictors.

Ana Sequeira is a PhD student at the University of Adelaide (Global Ecology Group). Her main research interests are to develop models applied to the marine environment to describe key environmental processes, species distribution patterns and ecological interactions.

The main objective of her PhD thesis is to investigate behavioural ecology of whale sharks. She is now trying to understand which environmental variables may affect whale shark distribution.

The whale shark (Rhincodon typus, Smith 1828) is the largest fish in the ocean and can reach more than 12 m in total length. Although little is known about their habitat selection or migration patterns, the whale shark appears to be a highly mobile species. They predictably form near shore aggregations in some coastal locations (e.g. off Ningaloo reef in Western Australia) what makes them the subject of highly lucrative marine ecotourism industries. Also, artisanal and small-scale fisheries for the species still exist in many parts of the tropics.

Since the whale sharks is classified a Vulnerable species (IUCN Red List), understanding their migratory behaviour became of chief importance as they can be travelling from regions where they are protected to regions where they are still harvested. Read the rest of this entry »

Comments : 2 Comments »
Tags: Fish, IUCN Red List, Marine biology, Ningaloo Reef, University of Adelaide, Whale shark
Categories : conservation, fish, fisheries, harvest, marine, modelling

Classics: Tragedy of the Commons

28 02 2011

Although not a conservation biology paper per se, Hardin’s classic essay (Hardin, 1968) changed the way we think about managing natural resources that lack definitive ownership.

The thesis of the “tragedy of the commons” is that individuals are inherently selfish and usually place their own interests first in using commonly owned resources, thereby resulting in their depletion. Hardin used a hypothetical and simplified situation based on medieval land tenure in Europe (herders sharing a common parcel of land) on which each herder was entitled to graze his cattle. Each herder maximized his gains by putting additional cattle onto the land, even if the carrying capacity of the common was exceeded and overgrazing ensued. The herder, by making an “individually rational decision,” received all the benefits from his cattle, but could in the process deplete the common resource for the entire group. If all herders make such selfish decisions then the common will be depleted, jeopardizing the livelihoods of all.

Read the rest of this entry »

Comments : 3 Comments »
Tags: Common-pool resource, Elinor Ostrom, environment, Garrett Hardin, Tragedy of the commons
Categories : biodiversity, conservation, corruption, environmental economics, fisheries, harvest, human overpopulation

Classics: Shifting baselines

14 02 2011

The Conservation Classics series will soon be collated and published in a special chapter for the book ‘Biodiversity’ to be published later this year by InTech. The chapter is co-authored by Barry Brook, Navjot Sodhi, Bill Laurance and me. This is a snippet of one ‘classic’ I haven’t yet really covered extensively on ConservationBytes.com.

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Daniel Pauly’s (1995) concept describes the way that changes to a system are measured against baselines which themselves are often degraded versions of the original state of the system. Pauly (1995) originally meant it in a fisheries context, where “… fisheries scientists sometimes fail to identify the correct ‘baseline’ population size (e.g., how abundant a fish species population was before human exploitation) and thus work with a shifted baseline”. It is now considered a mantra in fisheries and marine science (Jackson et al., 2001), but it has been extended to many other conservation issues. Yet, quantifying shifting baselines in conservation is difficult, with little empirical evidence (but see Jackson et al., 2001), despite the logic and general acceptance of its ubiquity by conservation scientists. Read the rest of this entry »

Comments : 4 Comments »
Tags: biodiversity, Daniel Pauly, environment, Fisheries science, Shifting baseline
Categories : conservation, decline, fish, fisheries, marine

Colour-blind sharks

3 02 2011

A few weeks ago I was interviewed on Channel 10 (Adelaide) about some new research coming out of the University of Western Australia regarding shark colour vision.

I’ve received permission from Channel 1o to reproduce the news snippet here. The first bloke interviewed is Associate Professor Nathan Hart, the study‘s lead author. I’m the bald one appearing in the middle at at the end.

It certainly was an interesting story, although two claims were made that probably needed better contextualisation.

First, the authors claim that because of this taxon’s colour blindness, they probably notice pigment transitions more when using visual cues to identify potential prey. What this means is that bright colours set against duller backgrounds might provide that contrast enough to attract sharks. The upshot from the interview is that brightly coloured and patterned togs (bathers) might make sharks think you are potentially a tasty treat. Read the rest of this entry »

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Tags: biodiversity, colour, conservation, Naturwissenschaften, shark, sharks, vision
Categories : biodiversity, conservation, exploitation, fish, fisheries, marine, southern Australia

Humans 1, Environment 0

27 09 2010

While travelling to our Supercharge Your Science workshop in Cairns and Townsville last week (which, by the way, went off really well and the punters gave us the thumbs up – stay tuned for more Supercharge activities at a university near you…), I stumbled across an article in the Sydney Morning Herald about the state of Australia.

That Commonwealth purveyor of numbers, the Australian Bureau of Statistics (ABS), put together a nice little summary of various measures of wealth, health, politics and environment and their trends over the last decade. The resulting Measures of Australia’s Progress is an interesting read indeed. I felt the simple newspaper article didn’t do the environmental components justice, so I summarise the salient points below and give you my tuppence as well. Read the rest of this entry »

Comments : 10 Comments »
Tags: Australia, Australian Bureau of Statistics, environment, extinction, Greenhouse gas, Overfishing, statistics
Categories : Australia, carbon, conservation, ecosystem services, environmental policy, fish, fisheries, habitat loss, harvest, health, human overpopulation, IUCN, logging, mammal, pollination, Red List

Global erosion of ecosystem services

14 09 2010

A few months ago I was asked to give a lecture about erosion of ecosystem services to students in the University of Adelaide‘s Issues in Sustainable Environments unit. I gave that lecture last week and just uploaded a slidecast of the presentation (with audio) today.

I’ve reproduced the lecture here for your viewing pleasure. I hope you find the 45-minute presentation useful. Note that the first few minutes cover me referring to the Biodiversity film short that I posted not too long ago.

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CJA Bradshaw

Comments : 2 Comments »
Tags: ecosystem services, Education, environment, University of Adelaide, webinar
Categories : anthropocene, Australia, biodiversity, carbon, climate change, coasts, coral reefs, deforestation, disease, ecosystem services, environmental policy, extinction, fire, fisheries, flood, fragmentation, governance, habitat loss, harvest, health, human overpopulation, illegal fishing, kelp, logging, marine protected area, MPA, pollination, predator, protected area, Red List, seagrass, shark, The University of Adelaide, threatened species, water

The lost world – freshwater biodiversity conservation

6 09 2010

Even the most obtuse, right-wing, head-in-the-sand, consumption-driven, anti-environment yob would at least admit that they’ve heard of forest conservation, the plight of whales (more on that little waste of conservation resources later) and climate change. Whether or not they believe these issues are important (or even occurring) is beside the point – the fact that this particular auto-sodomist I’ve described is aware of the issues is at least testament to growing concern among the general populace.

But so many issues in conservation science go unnoticed even by the most environmentally aware. Today’s post covers just one topic (I’ve covered others, such as mangroves and kelp forests) – freshwater biodiversity.

The issue is brought to light by a paper recently published online in Conservation Letters by Thieme and colleagues entitled Exposure of Africa’s freshwater biodiversity to a changing climate.

Sure, many people are starting to get very worried about freshwater availability for human consumption (and this couldn’t be more of an issue in Australia at the moment) – and I fully agree that we should be worried. However, let’s not forget that so many species other than humans depend on healthy freshwater ecosystems to persist, which feed back in turn to human benefits through freshwater filtering, fisheries production and arable soil accumulation.

Just like for the provision of human uses (irrigation, direct water consumption, etc.), a freshwater system’s flow regime is paramount for maintaining its biodiversity. If you stuff up the flow regime too much, then regardless of the amount of total water available, biodiversity will suffer accordingly.

Image by James Marvin Phelps (mandj98) via Flickr

Thieme and colleagues focus specifically on African freshwater systems, but the same problems are being seen worldwide (e.g., Australia’s Murray-Darling system, North America’s Colorado River system). And this is only going to get worse as climate change robs certain areas of historical rainfall. To address the gap in knowledge, the authors used modelled changes in mean annual runoff and discharge to determine fish species affected by 2050.

The discharge/runoff results were: Read the rest of this entry »

Comments : 5 Comments »
Tags: biodiversity, climate change, Ecosystem, environment, freshwater, water
Categories : Africa, climate change, conservation, ecosystem services, fish, fisheries, function, Murray River, Murray-Darling, water

100 actions to slow biodiversity loss

19 08 2010

I received an email a few days ago from Guillaume Chapron of the Swedish University of Agricultural Sciences (Sveriges lantbruksuniversitet) asking me to promote his ‘Biodiversity 100‘ campaign on ConservationBytes.com. I think it’s an interesting initiative, and so I’ll gladly spread the word.

Teaming up with George Monbiot of The Guardian, the Biodiversity 100 campaign seeks to encourage scientists and others to compile a list of 100 tasks that G20 governments should undertake to prove their commitment to tackling the biodiversity crisis.

Dr. Chapron writes: Read the rest of this entry »

Comments : 4 Comments »
Tags: biodiversity, Biodiversity 100, climate change, conservation, conservation biology, Ecosystem, Endangered species, environment, George Monbiot, Guillaume Chapron, integral fast reactor, nuclear energy, The Guardian
Categories : biodiversity, carbon, carbon trading, climate change, conservation, deforestation, environmental policy, environmental science, fisheries, habitat loss, harvest, health, human overpopulation, marine protected area, protected area, restoration

Marine protected areas: do they work?

13 08 2010

“One measure that often meets great resistance from fishermen, but is beloved by conservationists, is the establishment of marine protected or ‘no take’ areas.” Stephen J. Hall (1998)

I’m going to qualify this particular post with a few disclaimers; first, I am not involved in the planning of any marine protected areas (henceforth referred to as ‘marine parks’) in Australia or elsewhere; and second, despite blogging on the issue, I have never published in the discipline of protected area design (i.e, ‘conservation planning’ is not my area of expertise).

That said, it seems to becoming more imperative that I enter the fray and assess not only how marine parks should be designed, but how effective they really are (or can be). I’ve been asked by several conservation NGOs to provide some insight into this, so I thought I should ‘think aloud’ and blog a little mini-review about marine park effectiveness.

Clearly there is a trend to establish more marine parks around the world, and this is mainly because marine conservation lags so far behind terrestrial conservation. Indeed, Spalding et al. (2008) showed that only 4.1 % of continental shelf areas are incorporated within marine parks, and ~ 50 % of all marine ecoregions have less than 1 % marine park coverage across the shelf. Furthermore, marine protection is greatest in the tropical realms, while temperate realms are still poorly represented.

The question of whether marine parks ‘work’ is, however, more complicated than it might first appear. When one asks this question, it is essential to define how the criteria for success are to be measured. Whether it’s biodiversity protection, fisheries production, recreational revenue, community acceptance/involvement or some combination of the above, your conclusion is likely to vary from place to place.

Other complications are, of course, that if you cannot ensure a marine park is adequately enforced (i.e., people don’t respect the rules) or if you don’t actually place the park anywhere near things that need protecting, there will be no real net benefit (for any of the above-mentioned interest groups). Furthermore, most marine parks these days have many different types of uses allowed in different zones (e.g., no fishing, some fishing, recreational diving only, no boat transport, some shipping, etc., etc., etc.), so it gets difficult to test for specific effects (it’s a bit like a cap-and-trade legislation for carbon – too many rules and often no real net reduction in carbon emissions – but that’s another story).

All these conditions aside, I think it’s a good idea to present what the real experts have been telling us about marine park effectiveness from a biodiversity and fishing perspective over the last decade or so. I’ll summarise some of the major papers here and give an overall assessment at the end. I do not contend that this list is even remotely comprehensive, but it does give a good cross-section of the available evidence. Read the rest of this entry »

Comments : 10 Comments »
Tags: biodiversity, conservation, conservation planning, marine parks, marine protected areas
Categories : algae, biodiversity, conservation, coral reefs, ecosystem, environmental policy, exploitation, fish, fisheries, harvest, marine, marine protected area, MPA, planning, protected area, recovery, reserve

Interview with a social (conservation) scientist

22 06 2010

I was contacted recently by Josh Cinner, a self-titled ‘social’ scientist (now working at the Centre of Excellence for Coral Reef Studies) who has published rather a lot in the conservation literature. He was recently highlighted in the journal Science for his work, and he thought CB readers would enjoy the coverage. He stated to me:

“…as a social scientist, I have spent the past decade or so working with ecologists and managers trying to integrate social science better in conservation. There are often calls for the importance of integrating social science in conservation and I thought your blog readers might appreciate some high-level recognition of the importance of this. Additionally, as far as I can tell, this is the first of these profiles that has focused on someone working in conservation.”

So, while fully crediting the source of this article and its author, Helen Fields, here is the entire text reproduced for your reading pleasure.

In the late 1980s, things were not going well for the coral reefs at Jamaica’s Montego Bay Marine Park. Overfishing had taken out a lot of the fish that eat algae, and algae were taking over the reef. “It was a classic case of ecosystem decline,” human geographer Joshua Cinner says. He arrived in Jamaica in 1996 as a Peace Corps volunteer after graduating from the University of Colorado, Boulder, with a double major in environmental conservation and geography. He was particularly interested in parks and preserves.

He’d landed in the middle of a war. Lobbying by tour operators and others got spearfishing, one of the main culprits in overfishing, banned in the park. The ban did not go over well with local people. “All the park equipment got vandalized. We had park rangers get threatened; their families got threatened at spear point,” Cinner says. Spearfishing equipment is cheap and you don’t need a boat; men who do it are generally poor and are fishing as a last resort. “The cultural lens through which the fishermen viewed this issue was of struggle in a post-slavery society, of the rich, predominantly white expatriates making a law that oppressed the poorest of the poor locals to benefit the wealthy.”

The conflict got Cinner thinking about how conservation really works. “It wasn’t really about the ecology,” he says. “Making conservation work in Jamaica had a lot to do with understanding the local culture and people.” It also opened his eyes to the role oceans play. “The ocean is often viewed as an open-access resource. That extra layer of complexity interested me,” he says. “Land can often be private property,” but “the ocean is typically viewed as free for anyone to fish in, for anyone to swim in and use.” Read the rest of this entry »

Comments : 3 Comments »
Tags: biodiversity, conservation, coral reefs, fishing, Josh Cinner, marine protected areas, Tim McClanahan
Categories : Australia, conservation, coral reefs, environmental policy, exploitation, fish, fisheries, governance, harvest, illegal fishing, marine, marine protected area, MPA, prioritisation, protected area

Who are the world’s biggest environmental reprobates?

5 05 2010

Everyone is a at least a little competitive, and when it comes to international relations, there could be no higher incentive for trying to do better than your neighbours than a bit of nationalism (just think of the Olympics).

We rank the world’s countries for pretty much everything, relative wealth, health, governance quality and even happiness. There are also many, many different types of ‘environmental’ indices ranking countries. Some attempt to get at that nebulous concept of ‘sustainability’, some incorporate human health indices, and other are just plain black box (see Böhringer et al. 2007 for a review).

With that in mind, we have just published a robust (i.e., to missing data, choices for thresholds, etc.), readily quantifiable (data available for most countries) and objective (no arbitrary weighting systems) index of a country’s relative environmental impact that focuses ONLY on environment (i.e., not human health or economic indicators) – something no other metric does. We also looked at indices relative to opportunity – that is, looking at how much each country has degraded relative to what it had to start with.

We used the following metrics to create a combined environmental impact rank: natural forest loss, habitat conversion, fisheries and other marine captures, fertiliser use, water pollution, carbon emissions from land-use change and threatened species.

The paper, entitled Evaluating the relative environmental impact of countries was just published in the open-access journal PLoS One with my colleagues Navjot Sodhi of the National University of Singapore (NUS) and Xingli Giam, formerly of NUS but now at Princeton University in the USA.

So who were the worst? Relative to resource availability (i.e,. how much forest area, coastline, water, arable land, species, etc. each country has), the proportional environmental impact ranked (from worst) the following ten countries:

Singapore
Korea
Qatar
Kuwait
Japan
Thailand
Bahrain
Malaysia
Philippines
Netherlands

When considering just the absolute impact (i.e., not controlling for resource availability), the worst ten were:

Brazil
USA
China
Indonesia
Japan
Mexico
India
Russia
Australia
Peru

Interestingly (and quite unexpectedly), the authors’ home countries (Singapore, Australia, USA) were in either the worst ten proportional or absolute ranks. Embarrassing, really (for a full list of all countries, see supporting information). Read the rest of this entry »

Comments : 15 Comments »
Tags: biodiversity, conservation, countries, environmental impact, ranking, science
Categories : Asia, Australia, carbon, China, conservation, corruption, deforestation, environmental policy, environmental science, exploitation, fisheries, habitat loss, harvest, human overpopulation, Indonesia, Malaysia, Russia, The University of Adelaide, threatened species, USA

Fanciful mathematics and ecological fantasy

3 05 2010

Bear with me here, dear reader – this one’s a bit of a stretch for conservation relevance at first glance, but it is important. Also, it’s one of my own papers so I have the prerogative :-)

As some of you probably know, I dabble quite a bit in population dynamics theory, which basically means examining the mathematics people use to decipher ecological patterns. Why is this important? Well, most models predicting extinction risk, estimating optimal harvest rates, determining minimum viable population size and metapopulation dynamics for species’ persistence rely on good mathematical abstraction to be realistic. Get the maths wrong, and you could end up overharvesting a species (e.g., 99.99 % of fisheries management), underestimating extinction risk from habitat degradation, and getting your predictions wrong about the effects of invasive species. Expressed as an equation itself, (conservation) ecology = mathematics.

A long-standing family of models known as ‘phenomenological’ models (i.e., because they deal with the phenomenon of population size which is an emergent property of the mechanisms of birth, death and immigration) has been used to estimate everything from maximum sustainable yield targets, temporal abundance patterns, wildlife management interventions, extinction risk to epidemiological patterns. The basic form of the model describes the growth response, or the relationship between the population’s rate of change (growth) and its size. The simplest form (known as the Ricker), assumes a linear decline in population growth rate (r) as the number of individuals increases, which basically means that populations can’t grow indefinitely (i.e., they fluctuate around some carrying capacity if unperturbed). Read the rest of this entry »

Comments : 4 Comments »
Tags: biodiversity, conservation, mathematics, Richard Sibly, science
Categories : alien species, conservation, demography, exploitation, extinction, fisheries, harvest, invasive species, management, metapopulation, minimum viable population, modelling, mvp, population dynamics, population viability analysis, PVA

New April Issue of Conservation Letters out now

22 04 2010

Low intensity fire in a longleaf pine-wiregrass system

Another great line up of papers has just come out in the April Issue of Conservation Letters:

CJA Bradshaw

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Tags: biodiversity, conservation, conservation letters, science
Categories : biodiversity, carbon, carbon trading, climate change, conservation, coral reefs, fisheries, fragmentation, rain forests, REDD, seagrass

The spillover effect

18 04 2010

The so-called ‘spillover effect’ is a long-standing debate in conservation ecology. The idea is relatively simple – put in a marine reserve (or, no-take zone, park, whatever you wish to call it as long as it restricts blanket over-fishing) and the area around the reserve eventually profits from the nearby over-production of fish (and other taxa). The idea is very attractive because even if you’re thick enough not to understand the absolute necessity of marine reserves in our age of mass, global over-exploitation, at least you might have enough grey matter to appreciate the value of more fish ‘spilling over’ into your favourite fishing area. More proposed marine reserves have been sold to the more Luddite ‘stakeholder’ this way than I care to count.

However, as attractive an idea it was, early on in the marine reserve literature (i.e., the early Devonian 1990s), there was limited (Rowley 1994; Willis et al. 2003) or only circumstantial evidence (Russ & Alcala 1996; Roberts et al. 2005) for the effect. Indeed, many have suggested that the spillover benefit, if present, depends entirely on the size of the reserve and whether adjacent areas are managed at all (Allison et al. 1996; McClanahan & Mangi 2000). Others have even suggested that marine reserves can displace fishing effort into smaller areas and change local community structure enough to facilitate invasion by exotic species (Kellner & Hastings 2009).

It is happier time now that we have more than ample evidence that marine reserves do in fact result in species spillover (e.g.,Roberts et al. 2001; Russ et al. 2004; Abesamis & Russ 2005). So it is not with any great claims of novelty that I highlight Garry Russ & Angel Alcala’s latest paper, Enhanced biodiversity beyond marine reserve boundaries: the cup spilleth-over; rather, it’s how they quantify the long-term evidence, the mechanisms for how spillover occurs and how the community changes that they deserve a mention. Read the rest of this entry »

Comments : 14 Comments »
Tags: biodiversity, conservation, fishing, marine reserve, science
Categories : conservation, fish, fisheries, marine, marine protected area, reserve

The maggot of the plant world – mangroves

12 04 2010

I don’t know how many of my readers have waded through a mangrove swamp before – if you have, you’ll know it’s no ‘walk in the park’. They are generally mosquito-infested with waist-deep mud, have more creepy-crawlies than you can poke a stick at, and in some places (such as my former stomping ground, the Northern Territory of Australia) are down-right dangerous due to lovelies such as saltwater crocodiles.

But, most people probably don’t know just how important mangroves are. Just like the maggot who can sicken the hardiest of individual, under-appreciated mangroves provide major ecosystem services.

For example, did you know that mangroves:

Protect inland human communities from damage caused by coastal erosion and storms?
Provide critical habitat for a variety of terrestrial, estuarine and marine species? Indeed, it has been estimated that ~80 % of fish catches globally depend directly or indirectly on mangroves.
Are a source and sink for nutrients and sediments for other inshore marine habitats including seagrass beds and coral reefs?
Protect coasts from floods?
Process nutrient and organic matter?
Control sediment?
Provide at least US$1.6 billion per year in ecosystem services worldwide?
Sequester up to 25.5 million tonnes of carbon per year?
Provide more than 10% of essential organic carbon to the global oceans?
Occupy only 0.12% of the world’s total land area?

Pretty staggering, no?

So, even if you don’t like them, it’s difficult to deny that they’re important.

But, like almost every other habitats worldwide, mangroves are on the big downward slide. In a new paper in PLoS One by Polidoro & colleagues entitled The loss of species: mangrove extinction risk and geographic areas of global concern, the authors not only highlight the above benefits, they quantify just how badly the 70 mangrove species around the world are faring. Read the rest of this entry »

Comments : 7 Comments »
Tags: biodiversity, conservation, ecosystem services, mangrove, science
Categories : conservation, ecosystem services, environmental policy, extinction, fisheries, flood, habitat loss

Classics: Mesopredator Release

17 03 2010

Although popularised by Crooks & Soulé (1999), Soulé et al. (1988) first gave us the term that described how entire ecosystems can become unbalanced by a reduction of a higher trophic-level predator exerting so-called ‘top-down’ control on the abundance of species occupying lower trophic levels.

The idea had theoretical support in ecology (Wright et al. 1994; Litvaitis & Villafuerte 1996), but it was not until Soulé and colleagues described how the decline of dominant predators combines with habitat fragmentation to release top-down pressure on smaller predators, thereby increasing predation rates on prey lower down the trophic web.

Crooks & Soulé (1999) described an example where the decline in coyotes (Canis latrans) in combination with urbanisation-driven habitat fragmentation led to an increase in cat (Felis catus) densities and the subsequent decline in scrub-breeding birds. More recent examples attest to the importance of the mesopredator release phenomenon: Myers et al. (2007) described how the decline in large coastal shark species has allowed mesopredator cownose rays (Rhinoptera bonasus) to increase, leading to a reduction in commercially important shellfish densities; and Johnson et al. (2007) showed how dingoes (Canis lupus dingo) in Australia suppress populations of exotic predators such as cats and foxes, leading to more locally abundant populations of native marsupials (see previous post).

Conservation biologists have benefited from this knowledge because we’ve realised that top-order predators affect far more than their immediate prey. These examples really hit home how a fully functional community is required for ecosystem stability, so we should strive to preserve complete complements of communities, not just our favourite species.

CJA Bradshaw

Comments : 13 Comments »
Tags: biodiversity, conservation, conservation classics, mesopredator release, science
Categories : alien species, Australia, cat, conservation, exploitation, extinction, fisheries, harvest, invasive species, predator, shark, trophic cascades

No chance Europe will recover fish stocks

19 01 2010

Alternate title: When pigs fly and fish say ‘hi’.

I’m covering a quick little review of a paper just published online in Fish and Fisheries about the two chances Europe has of meeting its legal obligations of rebuilding its North East Atlantic fish stocks by 2015 (i.e., Buckley’s and none).

The paper entitled Rebuilding fish stocks no later than 2015: will Europe meet the deadline? by Froese & Proelß describes briefly the likelihood Europe will meet the obligations set out under the United Nations’ Law of the Sea (UNCLOS) of “maintaining or restoring fish stocks at levels that are capable of producing maximum sustainable yield” by 2015 as set out in the Johannesburg Plan of Implementation of 2002.

Using fish stock assessment data and several criteria (3 methods for estimating maximum sustainable yield [MSY], 3 methods for estimating fishing mortality [F_msy] & 2 methods for estimating spawning biomass [B_msy]), they conclude that 49 (91 %) of the examined European stocks will fail to meet the goal under a ‘business as usual’ scenario.

The upshot is that European fisheries authorities have been and continue to set their total allowable catches (TACs) too high. We’ve seen this before with Atlantic bluefin tuna and the International Conspiracy to Catch All Tunas. Seems like most populations of exploited fishes are in fact in the same boat (quite literally!).

It’s amazing, really, the lack of ‘political will’ in fisheries – driving your source of income into oblivion doesn’t seem to register in the short-sighted vision of those earning their associated living or those supposedly looking out for their long-term interests.

CJA Bradshaw

Froese, R., & Proelß, A. (2010). Rebuilding fish stocks no later than 2015: will Europe meet the deadline? Fish and Fisheries DOI: 10.1111/j.1467-2979.2009.00349.x

Pitcher, T., Kalikoski, D., Pramod, G., & Short, K. (2009). Not honouring the code Nature, 457 (7230), 658-659 DOI: 10.1038/457658a

Comments : 4 Comments »
Tags: biodiversity, conservation, fishing, Johannesburg Plan of Implementation, Law of the Sea, science
Categories : environmental policy, Europe, fish, fisheries, harvest, marine

Scoping the future threats and solutions to biodiversity conservation

4 12 2009

Way back in 1989, Jared Diamond defined the ‘evil quartet’ of habitat destruction, over-exploitation, introduced species and extinction cascades as the principal drivers of modern extinctions. I think we could easily update this to the ‘evil quintet’ that includes climate change, and I would even go so far as to add extinction synergies as a the sixth member of the ‘evil sextet’.

But the future could hold quite a few more latent threats to biodiversity, and a corresponding number of potential solutions to its degradation. That’s why Bill Sutherland of Cambridge University recently got together with some other well-known scientists and technology leaders to do a ‘horizon scanning’ exercise to define what these threats and solutions might be in the immediate future. It’s an interesting, eclectic and somewhat enigmatic list, so I thought I’d summarise it here. The paper is entitled A horizon scan of global conservation issues for 2010 and was recently published online in Trends in Ecology and Evolution.

In no particular order or relative rank, Sutherland and colleagues list the following 15 ‘issues’ that I’ve broadly divided into ‘Emerging Threats’ and ‘Potential Solutions’:

Emerging Threats

Microplastic pollution – The massive increase in plastics found in the world’s waterways and oceans really doesn’t have much focus right now in conservation research, but it should. We really don’t know how much we’re potentially threatening species with this source of pollution.
Nanosilver in wastewater – The ubiquity of antimicrobial silver oxide or ions in products these days needs careful consideration for what the waste might be doing to our microbial communities that keep ecosystems alive and functioning.
Stratospheric aerosols – A simultaneous solution and threat. Creating what would in effect be an artificial global cooling by injecting particles like sulphate aerosols into the stratosphere might work to cool the planet down somewhat. However, it would not reduce carbon dioxide, ocean acidification or other greenhouse gas-related changes. This strikes me as a potential for serious mucking up of the global climate and only a band-aid solution to the real problem.
Deoxygenation of the oceans – Very scary. Ironically today I was listening to a talk by Martin Kennedy on the deep-time past of ocean hypoxia and he suggests we’re well on our way to a situation where our shelf waters could essentially become too anoxic for marine life to persist. It’s happened before, and rapid climate change makes the prospect plausible within less than a century. And you thought acidification was scary.
Changes in denitrifying bacteria – Just like we’re changing the carbon cycle, we’re buggering up the nitrogen cycle as well. Changing our water bodies to nitrogen sources rather than sinks could fundamentally change marine ecosystems for the worse.
High-latitude volcanism – One of these horrible positive feedback ideas. Reducing high-latitude ice cover exposes all these slumbering volcanoes that once ‘released’, start increasing atmospheric gas concentrations and contributing to faster ice melt and sea level rise.
Trans-Arctic dispersal and colonisation – Warming polar seas and less ice mean fewer barriers to species movements. Expect Arctic ecosystems to be a hotbed of invasion, regime shifts and community reshuffling as a result.
Invasive Indo-Pacific lionfish – Not one I would have focussed on, but interesting. These spiny, venomous fish like to eat a lot of other species, and so represent a potentially important invasive species in the marine realm.
REDD and non-forested ecosystems – Heralded as a great potential coup for forest preservation and climate change mitigation, focussing on maintaining forests for their carbon sequestration value might divert pressure toward non-forested habitats and ironically, threaten a whole new sphere of species.
International land acquisition – Global financial crises and dwindling food supplies mean that governments are acquiring more and more huge tracts of land for agricultural development. While this might solve some immediate issues, it could potentially threaten a lot more undeveloped land in the long run, putting even more pressure on habitats.

Potential Solutions

Synthetic meat – Ever thought about eating a sausage grown in a vat rather than cut from a dead pig? It could become the norm and a way of reducing the huge pressure on terrestrial and aquatic systems for the production of livestock and fish for human protein provision.
Artificial life – Both a risk and a potential solution. While I’ve commented before on the pointlessness of cloning technology for conservation, the ability to create genomes and reinvigorate species on the brink is an exciting prospect. It’s also frightening as hell because we don’t know how all these custom-made genomes might react and transform naturally evolved ones.
Biochar – Burn organic material (e.g., plant matter) in the absence of oxygen, you get biochar. This essentially sequesters a lot of carbon that can then be put underground. The upshot is that agricultural yields can also increase. Would there be a trade-off though between land available for biochar sequestration and natural habitats?
Mobile-sensing technology – Not so much a solution per se, but the rapid acceleration of remote technology will make our ability to measure and predict the subtleties of ecosystem and climate change much more precise. A lot more work and application required here.
Assisted colonisation – I’ve blogged about this before. With such rapid shifts in climate, we might be obliged to move species around so that they can keep up with rapidly changing conditions. Many pros and cons here, not least of which is exacerbating the invasive species problems around the globe.

Certainly some interesting ideas here and worth a thought or two. I wonder if the discipline of ‘conservation biology’ might even exist in 50-100 years – we might all end up being climate or agricultural engineers with a focus on biodiversity-friendly technology. Who knows?

CJA Bradshaw

Sutherland, W., Clout, M., Côté, I., Daszak, P., Depledge, M., Fellman, L., Fleishman, E., Garthwaite, R., Gibbons, D., & De Lurio, J. (2009). A horizon scan of global conservation issues for 2010 Trends in Ecology & Evolution DOI: 10.1016/j.tree.2009.10.003

Comments : 12 Comments »
Tags: biodiversity, conservation, horizon scanning, science
Categories : acidification, agriculture, alien species, aquaculture, Arctic, biocarbon, biodiversity, biosequestration, carbon, carbon trading, climate change, cloning, conservation, deforestation, environmental engineering, fish, fisheries, habitat loss, invasive species, marine, pollution, research, threatened species, trophic cascades

Susceptibility of sharks, rays and chimaeras to global extinction

10 11 2009

Quite some time ago my colleague and (now former) postdoctoral fellow, Iain Field, and I sat down to examine in gory detail the extent of the threat to global populations of sharks, rays and chimaeras (chondrichthyans). I don’t think we quite realised the mammoth task we had set ourselves. Several years and nearly a hundred pages later, we have finally achieved our goal.

Introducing the new paper in Advances in Marine Biology entitled Susceptibility of sharks, rays and chimaeras to global extinction by Iain Field, Mark Meekan, Rik Buckworth and Corey Bradshaw.

The paper covers the following topics:

Chondrichthyan Life History

Niche breadth

Age and growth

Reproduction and survival

Past and Present Threats

Fishing

Beach meshing

Habitat loss

Pollution and non-indigenous species

Chondrichthyan Extinction Risk

Drivers of threat risk in chondrichthyans and teleosts

Global distribution of threatened chondrichthyan taxa

Ecological, life history and human-relationship attributes

Threat risk analysis

Relative threat risk of chondrichthyans and teleosts

Implications of Chondrichthyan Species Loss on Ecosystem Structure, Function and Stability

Ecosystem roles of predators

Predator loss in the marine realm

Ecosystem roles of chondrichthyans

Synthesis and Knowledge Gaps

Role of fisheries in future chondrichthyan extinctions

Climate change

Extinction synergies

Research needs

common skate As mentioned, quite a long analysis of the state of sharks worldwide. Bottom line? Well, as most of you might already know sharks aren’t doing too well worldwide, with around 52 % listed on the IUCN’s Red List of Threatened Species. This compares interestingly to bony fishes (teleosts) that, although having only 8 % of all species Red-Listed, are generally in higher-threat Red List categories. We found that body size (positively) and geographic range (negatively) correlated with threat risk in both groups, but Red-Listed bony fishes were still more likely to be categorised as threatened after controlling for these effects.

blue shark In some ways this sort of goes against the notion that sharks are inherently more extinction-prone than other fish – a common motherhood statement seen at the beginning of almost all papers dealing with shark threats. What it does say though is that because sharks are on average larger and less fecund than your average fish, they tend to bounce back from declines more slowly, so they are more susceptible to rapid environmental change than your average fish. Guess what? We’re changing the environment pretty rapidly.

We also determined the spatial distribution of threat, and found that Red-Listed species are clustered mainly in (1) south-eastern South America; (2) western Europe and the Mediterranean; (3) western Africa; (4) South China Sea and South East Asia and (5) south-eastern Australia.

Now, what are the implications for the loss of these species? As I’ve blogged recently, the reduction in predators in general can be a bad thing for ecosystems, and sharks are probably some of the best examples of ecosystem structural engineers we know (i.e., eating herbivores; ‘controlling’ prey densities, etc.). So, we should be worried when sharks start to disappear. One thing we also discovered is that we still have a rudimentary understanding of how climate change will affect sharks, the ways in which they structure ecosystems, and how they respond to coastal development. Suffice it to say though that generally speaking, things are not rosy if you’re a shark.

We end off with a recommendation we’ve been promoting elsewhere – we should be managing populations using the minimum viable population (MVP) size concept. Making sure that there are a lot of large, well-connected populations around will be the best insurance against extinction.

CJA Bradshaw

I.C. Field, M.G. Meekan, R.C. Buckworth, & C.J.A. Bradshaw (2009). Susceptibility of Sharks, Rays and Chimaeras to Global Extinction Advances in Marine Biology, 56, 275-363 : 10.1016/S0065-2881(09)56004-X

Comments : 5 Comments »
Tags: biodiversity, conservation, marine, science, shark
Categories : climate change, exploitation, extinction, fish, fisheries, harvest, illegal fishing, IUU fishing, management, marine protected area, minimum viable population, mvp, PVA, shark

How to make an effective marine protected area

22 09 2009

Here’s a nice little review from the increasingly impressive Frontiers in Ecology and the Environment which seems to be showcasing a lot of good conservation research lately.

As we know, the world’s oceans are under huge threat, with predictions of 70 % loss of coral reefs by 2050, decline in kelp forests, loss of seagrasses, over-fishing, pollution and a rapidly warming and acidifying physical environment. Given all these stressors, it is absolutely imperative we spend a good deal of time thinking about the right way to impose restrictions on damage to marine areas – the simplest way to do this is via marine protected areas (MPA).

The science of MPA network design has matured over the last 10-20 years such that there is a decent body of literature now on what we need to do (now the policy makers just have to listen – some progress there too, but see also here). McLeod and colleagues in the latest issue of Frontiers in Ecology and the Environment have published a review outlining the best, at least for coral reefs, set of recommendations for MPA network design given available information (paper title: Designing marine protected area networks to address the impacts of climate change). Definitely one for the Potential list.

Here’s what they recommend:

Size

bigger is always better
minimum diameter of an MPA should be 10-20 km to ensure exchange of propagules among protected benthic populations

Shape

simple shapes best (squares, rectangles)
avoid convoluted shapes to minimise edge effects

Representation

protect at least 20-30 % of each habitat

Replication

protect at least 3 examples of each marine habitat

Spread

select MPA in a variety of temperature regimes to avoid risk of all protected reefs succumbing to future climate changes

Critical Areas

protect nursery areas, spawning aggregations, and areas of high species diversity
protect areas demonstrating natural resilience or rapid recovery from previous disturbances

Connectivity

measure connectivity between MPA to ensure replenishment
space maximum distance of 15-20 km apart
include whole ecological units
buffer core areas
protect adjacent areas such as outlying reefs, seagrass beds, mangroves

Ecosystem Function

maintain key functional groups of species (e.g., herbivorous fishes)

Ecosystem Management

embed MPA in broader management frameworks addressing other threats
address and rectify sources of pollution
monitor changes

Of course, this is just a quick-and-dirty list as presented here – I highly recommend reading the review for specifics.

CJA Bradshaw

McLeod, E., Salm, R., Green, A., & Almany, J. (2009). Designing marine protected area networks to address the impacts of climate change Frontiers in Ecology and the Environment, 7 (7), 362-370 DOI: 10.1890/070211