Sex on the beach

2 10 2018
Female green turtles (Chelonia mydas) spawning (top) and diving (bottom) on Raine Island (Great Barrier Reef, Queensland, Australia) — photos courtesy of Ian Bell. This species is ‘Endangered’ globally since 1982, mainly from egg harvesting (poaching conflict in Mexico for olive ridley Lepidochelys olivacea featured by National Geographic’s video here), despite the success of conservation projects (39). Green turtles inhabit tropical and subtropical seas in all oceans. Adults can grow > 150 kg and live for up to ~ 75 years. Right after birth, juveniles venture into the open sea to recruit ultimately in coastal areas until sexual maturity. They then make their first reproductive migration, often over 1000s of km (see footage of a real dive of a camera-equipped green turtle), to reach their native sandy beaches where pregnant females will lay their eggs. Each female can deposit more than one hundred eggs in her nest, and in several clutches in the same season because they can store the sperm from multiple mating events.

When sex is determined by the thermal environment, males or females might predominate under sustained climatic conditions. A study about marine turtles from the Great Barrier Reef illustrates how feminisation of a population can be partitioned geographically when different reproductive colonies are exposed to contrasting temperatures.

Fortunately, most people in Western societies already perceive that we live in a complex blend of sexual identities, far beyond the kind of genitals we are born with. Those identities start to establish themselves in the embryo before the sixth week of pregnancy. In the commonest scenario, for a human foetus XY with one maternal chromosome (X) and one paternal (Y) chromosome, the activation of the Sry gen (unique to Y) will trigger the differentiation of testicles and, via hormonal pathways, the full set of male characteristics (1).

Absence of that gene in an XX embryo will normally lead to a woman. However, in just one of many exceptions to the rule, Sry-expression failure in XY individuals can result in sterile men or ambiguous genitals — along a full gradient of intermediate sexes and, potentially, gender identities. A 2015 Nature ‘News’ feature echoes two extraordinary cases: (i) a father of four children found to bear a womb during an hernia operation, and (ii) a pregnant mother found to host both XX and XY cells during a genetic test – with her clinical geneticist stating “… that’s the kind of science-fiction material for someone who just came in for an amniocentesis” (2). These real-life stories simply reflect that sex determination is a complex phenomenon.

Three ways of doing it

In nature, there are three main strategies of sex determination (3) — see scheme here: Read the rest of this entry »





The European Union just made bioenergy worse for biodiversity

21 08 2018

bioenergy2While some complain that the European Union (EU) is an enormous, cumbersome beast (just ask the self-harming Brexiteers), it generally has some rather laudable legislative checks and balances for nature conservation. While far from perfect, the rules applying to all Member States have arguably improved the state of both European environments, and those from which Europeans source their materials.

But legislation gets updated from time to time, and not always in the ways that benefit biodiversity (and therefore, us) the most. This is exactly what’s just happened with the new EU Renewable Energy Directive (RED) released in June this year.

Now, this is the point where most readers’ eyes glaze over. EU policy discussions are exceedingly dry and boring (I’ve dabbled a bit in this arena before, and struggled to stay awake myself). But I’ll try to lighten your required concentration load somewhat by being as brief and explanatory as possible, but please stay with me — this shit is important.

In fact, it’s so important that I joined forces with some German colleagues with particular expertise in greenhouse-gas accounting and EU policy — Klaus Hennenberg and Hannes Böttcher1 of Öko-Institut (Institute of Applied Ecology) in Darmstadt — to publish an article available today in Nature Ecology and Evolution.

bioenergy4So back to the RED legislation. The original ‘RED 2009‘ covered reductions of greenhouse-gas emissions and the mitigation of negative impacts on areas of high biodiversity value, such as primary forests, protected areas, and highly biodiverse grasslands, and for areas of high carbon stock like wetlands, forests, and peatlands.

But RED 2009 was far from what we might call ‘ambitious’, because globally mandatory criteria on water, soil and social aspects for agriculture and forestry production were excluded to avoid conflicts with rules of the World Trade Organization.

Nor did RED 2009 apply to all bioenergy types, and only included biofuels used in transport, including gaseous and solid fuels, and bioliquids used for electricity, heating, and cooling. But RED 2009 requirements also applied to all raw materials sourced from agriculture and forestry, especially as forest biomass is explicitly mentioned as a raw material for the production of advanced biofuels in the RED 2009 extension from 2015.

Thus, one could conceivably call RED 2009 criteria ‘minimum safeguards’.

But as of June this year, the EU accepted a 2016 proposal to recast RED 2009 into what is now called ‘RED II’. While the revisions might look good on paper by setting new incentives in transport (advanced biofuels) and in heating and cooling that will likely increase the use of biomass sourced from forests, and by extending the directive on solid and gaseous biomass, the amendments unfortunately take some huge leaps backwards in terms of sustainability requirements.

These include the following stuff-ups: Read the rest of this entry »





Biodiversity is everyone’s responsibility

13 07 2018

Workspace: Team Of Diverse Workers Put Hands TogetherI’m not sure if many South Australians are aware of this, but the Parliamentary Inquiry into Biodiversity by the Environment, Resources and Development Committee presented a report to the 53rd Parliament of South Australia in March 2017. I thought it worthwhile reproducing their executive summary here on CB.com (I’ve highlighted the text that I deem to be rather insightful and simultaneously damning from our own elected government representatives):

This report summarises the findings and recommendations of the South Australian Parliament’s Environment, Resources and Development Committee’s inquiry into biodiversity in South Australia. Specifically, the inquiry investigated the regulatory and policy framework to determine whether it appropriately supports terrestrial and marine ecological processes, biodiversity values and abates species extinction.

The Committee found that in spite of the efforts of the State and Federal governments, industry and private landholders in South Australia, the condition of biodiversity in the State continues to decline. Species extinctions have occurred in the past and a further “extinction debt” still exists. There is no reason to believe that this trend will improve without a change to the way we approach biodiversity conservation.

A key theme to emerge from the Inquiry is that biodiversity conservation needs to be everyone’s responsibility; State and Federal government, industry, the broader community, and private landholders.

This also means that biodiversity conservation needs to occur across both public and private land, with actions coordinated at a landscape scale.

Making biodiversity conservation everyone’s responsibility requires a range of measures, including legislative reform, improved management of threats and greater involvement of the community. The provision of greater resources would yield faster results.

This report has focused on several key themes that emerged from submissions to the Inquiry.

Regulating for better biodiversity – South Australia’s legislative framework

South Australia’s current legislative framework does not provide for optimum biodiversity outcomes.

Three key issues contribute to this –

  • an out-of-date suite of environmental legislation that lacks cohesion and consistency, particularly regarding enforcement and compliance provisions;
  • inadequate and incomplete processes for identifying and protecting at-risk elements that need special measures (e.g. for protection of specific threatened species and ecological communities); and
  • inadequate consideration of biodiversity conservation in legislation that regulates human activities. In particular, there is a lack of cohesion between the environmental legislative and policy framework and land use planning, assessment and approval.
  • Statutory fragmentation of biodiversity considerations – that is, consideration of different aspects of biodiversity under different pieces of legislation – results in lack of cohesion and consistency, duplication and inefficiency, and makes it difficult to implement a landscape approach or to identify strategic opportunities and risks.

Taken as a whole, current enforcement provisions do not provide for effective and proportionate compliance action. Enforcement and compliance provisions across the relevant legislation are uneven in their approach. For example, penalties appear to be disproportionate and not risk-based (although there are some exceptions). Modern enforcement tools such as compliance orders, civil remedies and alternative penalties (such as administrative penalties, payment of damages including exemplary damages, remediation orders etc) are not included in all relevant legislation. There is some duplication in offences and inconsistency in the types of sanctions and penalty ranges.

There is an urgent need to amend the legislative framework to support any attempt to improve biodiversity outcomes.

The best approach will be based on clear, shared responsibility for biodiversity outcomes, supported by individual accountability. However, such a change will require policy development and drive.

To ensure forward momentum and improvements in the short term while developing the policy settings to support such a step-change, a staged approach could be implemented. There are various ways this could be achieved.

The Committee suggests a 3-stage approach to reforming the legislative framework. The Committee recommends the creation of a Biodiversity Expert Panel that is responsible for advancing this 3-stage approach.

  1. The first stage will involve amendments to improve operation and effectiveness of the regulatory regime within current policy settings, acknowledging that as a result of Stage 3, provisions may be altered or moved into different pieces of legislation. Amendments generally would be to the existing ‘environmental’ Acts, and primarily to the National Parks and Wildlife Act 1972 and Native Vegetation Act 1991. They would include many of the specific areas for amendment identified in EDO submissions (2011 & 2015) as well as in the SA Government submission, for example, beginning with amendments to improve current environmental legislation.
  2. Stage 2 would progress to amendments to improve integration between Acts and improve support for landholders and community participation.
  3. Stage 3 would implement a system whereby all resource use and management would be managed by one piece of legislation, with protection of biodiversity and sustainable development at its core. Provisions for protected area management, and for the scientific work involved in identifying threatened species and communities, may be contained in separate legislation.

Threats, ecological resilience and restoration

The State’s native biodiversity is facing myriad of current threats, including habitat loss and fragmentation (due to development and changing land-use), pest plants and animals, and control burn regimes. There is a need for more stringent vegetation protection, better informed and enacted control and management strategies of known pest plants and animals, and a revision of burning regimes.

Future threats to the State’s biodiversity will be largely driven by climate change impacts and the interaction with existing major threats (e.g. urbanisation and changing land use). Adequately preparing for and managing such future threats will require knowledge of projected changes and pro-active preparation for such changes.

Working with the community

Involvement of the community is an essential part of any biodiversity conservation strategy for the State. It is a foundation stone for moving to a point where biodiversity conservation is everyone’s business.

Community engagement will become increasingly important for biodiversity conservation, especially given the growing role of volunteers to support works on public land as well as the voluntary conservation efforts of private landholders. The expanding role of volunteers reenforces that biodiversity conservation is everyone’s business.

South Australia’s approach to biodiversity conversation on private land needs to be reinvigorated.

Cross cutting themes

There were several cross cutting themes identified in submissions to the Inquiry. There was broad recognition of the strong cultural and historic significance of elements of biodiversity to Aboriginal people, and that this is often poorly understood outside those communities. Continuing to identify ways for Aboriginal people to contribute to land and water management in South Australia remains a priority.

With respect to knowledge generation, critical knowledge gaps exist that need to be filled and existing knowledge is not being adequately understood, communicated or applied. From a resourcing perspective, there is concern that insufficient funds are being allocated to biodiversity conservation, which is affecting work on public and private lands.

The management of over-abundant species in South Australia remains a challenge, noting the recent impacts of long-nose fur seals in the Lower Lakes and Coorong, and ongoing concerns regarding the impact of animals such as little corellas and some species of kangaroos on negative vegetation.

 





Communicating climate change

5 06 2018

Both the uncertainty inherent in scientific data, and the honesty of those scientists who report such data to any given audience, can sow doubt about the science of climate change. The perception of this duality is engrained in how the human mind works. We illustrate this through a personal experience connecting with global environmentalism, and synthesise some guidelines to communicate the science of climate disruption by humans.

EskimoTote_English

Courtesy of Toté (www.elcomic.es)

In January 2017, the Spanish environmental magazine Quercus invited us to give a talk, at the Cabinet of Natural History in Madrid, about our article on the effects of climate change on the feeding ecology of polar bears, which made to Quercuscover in February 2017 (1) — see blog post here. During questions and debate with the audience (comprising both scientists and non-scientists), we displayed a graph illustrating combinations of seven sources of energy (coal, water, gas, nuclear, biomass, sun and wind) necessary to meet human society’s global energy needs according to Barry Brook & Corey Bradshaw (2). That paper supports the idea that nuclear energy, and to a lesser extent wind energy, offer the best cost-benefit ratios for the conservation of biodiversity after accounting for factors intimately related to energy production, such as land use, waste and climate change.

While discussing this scientific result, one member of the audience made the blunt statement that it was normal that a couple of Australian researchers supported nuclear energy since Australia hosts the largest uranium reservoirs worldwide (~1/3 of the total). The collective membership of Quercus and the Cabinet of Natural History is not suspicious of lack of awareness of environmental problems, but a different matter is that individuals can of course evaluate a piece of information through his/her own and legitimate perspective.

The stigma of hypocrisy

Indeed, when we humans receive and assimilate a piece of information, our (often not self-conscious) approach can range from focusing on the data being presented to questioning potential hidden agendas by the informer. However, the latter can lead to a psychological trap that has been assessed recently (3) — see simple-language summary of that assessment in The New York Times. In one of five experiments, a total of 451 respondents were asked to rank their opinion about four consecutive vignettes tracking the conversation between two hypothetical individuals (Becky & Amanda) who had a common friend. During this conversation, Amanda states that their friend is pirating music from the Internet, and Becky (who also illegally downloads music) can hypothetically give three alternative answers: Read the rest of this entry »





Penguins cheated by ecosystem change

13 03 2018

Jorge Drexler sings “… I was committed not to see what I saw, but sometimes life is more complex than what it looks like …”*. This excerpt by the Oscar-winning Uruguayan singer seems to foretell the theme of this blog: how the ecological complexity of marine ecosystems can elicit false signals to their predators. Indeed, the fidelity of marine predators to certain feeding areas can turn demographically detrimental to themselves when the amount of available food shrinks. A study of jackass penguins illustrates the phenomenon in a context of overfishing and ocean warming.

CB_JackassPenguinsEcologicalTrapPhoto

Adult of jackass penguin (Spheniscus demersus) from Robben Island (South Africa) — in the inset, one of the first juveniles released with a satellite transmitter on its back. The species is ‘Endangered’ under IUCN’s criteria (28), following a recent halving of the total population currently estimated at ~ 80,000 adults. Jackass penguins are the only penguins living in Africa, and owe their common name to their vocalisations (you can hear their braying sounds here); adults are ~ 50 cm tall and weigh ~ 3 kg. Photos courtesy of Richard Sherley.

Surface temperature, dissolved oxygen, acidity and primary productivity are, by and large, the top four environmental factors driving the functionality of marine ecosystems (1). Growing scientific evidence supports the idea that anthropogenic warming of the atmosphere and the oceans correlates with this quartet (2). For instance, marine primary productivity is enhanced by increased temperatures (3), but a warmer sea surface intensifies stratification, i.e., stacked layers of seawater with contrasting physical and chemical properties.

In coastal areas experiencing ‘upwelling’ (where winds displace surface water, allowing deep water laden with nutrients to reach the euphotic zone where plankton communities feast), stratification weakens upwelling currents and, in turn, limits the growth of plankton (4) that fuels the entire trophic web, including our fisheries. The study of these complex trophic cascades is particularly cumbersome from the perspective of large marine predators because of their capacity to move long distances, from hundreds to thousands of kilometres (5), with strong implications for their conservation (6).

With those caveats in mind, Richard Sherley and colleagues satellite-tracked the movement of 54 post-fledged, juvenile jackass penguins (Spheniscus demersus) for 2-3 years (7). All individuals had been hatched in eight colonies (accounting for 80% of the global population), and were equipped with platform terminal transmitters. Jackass penguins currently nest in 28 island and mainland locations between South Africa and Namibia. Juveniles swim up to 2000 km in search of food and, when approaching adulthood, return to their native colonies where they reproduce and reside for the remainder of their lives (watch individuals swimming here).

The natural history of this species is linked to the Southern Hemisphere’s trade winds (‘alisios’ for Spanish speakers), which blow from the southeast to the tropics. In the South Atlantic, trade winds sustain the Benguela Current, the waters of which surface from some 300 m of depth and fertilise the marine ecosystems stretching from the Western coasts of South Africa to Angola (8). Read the rest of this entry »





Offshore Energy & Marine Spatial Planning

22 02 2018

FishingOffshoreWind

I have the pleasure (and relief) of announcing a new book that’s nearly ready to buy, and I think many readers of CB.com might be interested in what it describes. I know it might be a bit premature to announce it, but given that we’ve just finished the last few details (e.g., and index) and the book is ready to pre-order online, I don’t think it’s too precocious to advertise now.

9781138954533-2

A little history is in order. The brilliant and hard-working Katherine Yates (now at the University of Salford in Manchester, UK) approached me back in 2014 to assist her with co-editing the volume that she wanted to propose for the Routledge Earthscan Ocean series. I admit that I reluctantly agreed at the time, knowing full well what was in store (anyone who has already edited a book will know what I mean). Being an active researcher in energy and biodiversity (perhaps not so much on the ‘planning’ side per se) certainly helped in my decision.

And yes, there were ups and downs, and sometimes it was a helluva lot of work, but Katherine certainly made my life easier, and she has finally driven the whole thing to completion. She deserves most of the credit.

Read the rest of this entry »





Tiny, symbiotic organisms protect corals from predation and disease

20 12 2017
hydrozoan polyp

Hydrozoan polyps living on the surface of a coral (photo credit: S. Montano)

Corals could have some unexpected allies to cope with the multi-faceted threats posed by climate change.

In a new study published today in Proceedings of the Royal Society B, Montano and colleagues show how tiny hydrozoans smaller than 1 mm and commonly found in dense colonies on the surface of hard corals (see above photo) play an important ecological role.

Visually examining ~ 2500 coral colonies in both Maldivian and Saudi Arabian reefs, the scientists searched for signs of predation, temperature-induced stress, and disease. For each colony, they also recorded the presence of symbiotic hydrozoans. They demonstrated that corals living in association with hydrozoans are much less prone to be eaten by corallivorous (i.e., ‘coral-eating’) fish and gastropods than hydrozoan-free corals.

A likely explanation for this pattern could be the deterring action of hydrozoan nematocysts (cells capable of ejecting a venomous organelle, which are the same kinds found in jellyfish tentacles). An individual hydrozoan polyp of less than 1 mm clearly cannot cope with a corallivorous fish that is a billions of times larger, yet hydrozoans can grow at high densities on the surface of corals (sometimes > 50 individuals per cm2). This creates a sort of a continuous, ‘urticating‘ carpet that can discourage fish from foraging. Read the rest of this entry »