I’m on a break…

Regular readers of this blog (I’m assuming here I have some) will have noticed a distinct lack of action round these parts lately.  Rest assured I’m still here, but busy with analysing more data than I know what to do with, a paid writing gig, and running around after a fast-crawling toddler.  Which unfortunately leaves little time for this unpaid writing gig, and it looks like thats going to be the case for the forseable future.   I hope I’ll get back to blogging at some point, so will be leaving this site here for all to read in the meantime.

New Zealand forests still threatened, but not THAT threatened

Last week Conservation International published its list of the world’s ten most threatened forest hotspots, where biodiversity and endemism is high and less than 10% of the original habitat is remaining.  New Zealand was, somewhat shockingly, number 2 on their list.  I must admit I thought this was a little odd – especially as their list claims we have only 5% of our forest (which is listed as tropical and subtropical broadleaf forest) remaining – and well, it turns out the folks at Conservation International were a little confused.

Apparently New Zealand was confused with New Caledonia, and is actually ranked number 22 on the list, with 22% of its original forest cover remaining.  Easy mistake to make, I guess (although the folks over at Kiwiblog of course think its all a big conspiracy of the part of the Greens).

So its not quite as alarming as we thought, but this is no reason to be complacent about the state of our forests.  A timely bit of research published online in the journal Science last week shows how even small changes in the makeup of our forests, like extinction of one or two key species, can have a cascading effect on biodiversity.  I’m not sure that it matters whether we are number 2 or 22 on Conservation International’s list, when we still have one of the worst records of biodiversity loss in the world.

Cheetah genetic diversity revisited

Another chapter has been added to the story of genetic variation in the cheetah, with a paper out in next month’s Molecular Biology and Evolution journal giving a detailed description of variation at key immune genes in the species.  I first became familiar with the cheetah story as a PhD student when I was studying genetic diversity in the black robin.  At the time the cheetah was something of a poster child for the perils of low genetic variation, but this most recent paper suggests that their immune system is not as genetically invariant as first thought, and they may not be so vulnerable to disease after all.

RIP Richard Henry

From Codfish Island this morning comes the sad news of the death of Richard Henry, the last remaining Fiordland kakapo.  Richard Henry was captured in Fiordland in 1975, at a time when kakapo were thought to be virtually extinct.  All other kakapo currently living are descended from birds discovered on Stewart Island in 1977.  A 2003 study* showed that kakapo have low genetic variation, with the exception of Richard Henry who was genetically distinct from all the Stewart Island birds.  Richard Henry had thus become an important player in the kakapo recovery program as the recovery team attempted to boost the genetic diversity of the species. 

This DNA fingerprint of kakapo clearly shows how distinct Richard Henry was. His fingerprint is marked with an asterisk - all the others are from Stewart Is. birds

More from Stuff.co.nz:

One of the key players in the Kakapo Recovery Programme was found dead on Codfish Island yesterday, marking the end of an era.

Kakapo Richard Henry was discovered by one of the recovery team members after what was believed to be an 80-year life.

Richard Henry, who was named after a Victorian conservationist who pioneered kakapo recovery, was originally found as an adult in Fiordland in 1975 when his species was believed to be extinct.

Since that time he has contributed to the genetic diversity of kakapo in the recovery programme and is well known for his efforts.

Department of Conservation programme scientist Ron Moorhouse said Richard Henry would be sorely missed by everyone who knew him.

“Richard Henry was a living link to the early days of kakapo recovery and perhaps even to a time before stoats when kakapo could boom unmolested in Fiordland,” he said.

Richard Henry was showing signs of ageing for some time before he was found, including blindness in one eye, slow movement and wrinkles, he said.

Meanwhile, the kakapo breeding season is under way on Codfish and Anchor islands and the first eggs are expected to appear next month.

*Disclaimer: I was part of that study, and the fingerprint gel is one of my more arty pieces of molecular biology, so I thought I’d post it in tribute.

The reference is: Miller HC, Lambert DM, Millar CD, Robertson BC, Minot EO (2003) Minisatellite DNA profiling detects lineages and parentage in the endangered kakapo (Strigops habroptilus) despite low microsatellite DNA variation. Conservation Genetics, 4: 265-274.

 

Presence of observers prevents fur seal attacks

Further to the recent attacks on fur seals in Kaikoura, comes a timely study just published in Conservation Biology.  Alejandro Acedevo-Gutierrez and Lisa Acedevo of Western Washington University, and Laura Boren, DoC’s national marine mammal coordinator, found that the presence of an official-looking volunteer stationed at a popular seal viewing areas was enough to deter tourists from harassing seals. 

The researchers carried out their study at Ohau stream waterfall, Kaikoura, near the location of the recent attacks that saw 23 animals bludgeoned to death.  Over a period of 9 months they recorded the behaviour of tourists in the presence or absence of a volunteer observer who was wearing a neon vest and made to look “official”.  Tourists were deemed to be harassing the seals when they approached the animals to within a few metres or threw an object at them.  They found that harassment dropped by two-thirds when the observer was present – from 38.4% down to 13% of groups with at least one person who harassed the seals  - even if the observer said nothing to the tourists. 

Viewing of fur seals is regulated by the Marine Mammals Protection Act 1992, but the researchers had previously found that simply having a sign up stating these regulations does nothing to ensure that tourists actually comply.  Having an actual person wearing a neon vest is far more effective at preventing harassment, even if this person is a volunteer with no authority to actually enforce compliance with the regulations. 

The researchers point out that using volunteers in this way is a cheap and effective way of managing tourist-wildlife interactions at popular wildlife viewing areas, and has the added bonus of observers being able to educate tourists about the animals. They found that approximately half the tourist groups approached the observer and asked questions about the behaviour of the seals, and all of them had misconceptions about how to behave around young seals.

Other posts on sciblogs about the fur seal attacks are here and here

Reference:

Acedevo-Gutierrez et al.  Effects of the Presence of Official-Looking Volunteers on Harassment of New Zealand Fur Seals.  Conservation Biology. Article first published online: 3 DEC 2010 | DOI: 10.1111/j.1523-1739.2010.01611.x

Great wildlife photography

Some fantastic wildlife snaps from the winners of the GDT European Wildlife Photographer of the Year (the humingbird is my favourite)

http://www.guardian.co.uk/environment/gallery/2010/nov/17/gdt-wildlife-photography#/?picture=368699851&index=0

Tuatara tuesday – sex determination in a warming world

Seeing as reptile reproduction seems to be a bit of a hot topic right now, I thought it was time to talk about sex determination in tuatara.

Tuatara do things a little differently to other reptiles when it comes to sex determination – not because they have temperature-dependent sex determination (thats common to lots of reptiles), but because their pattern of temperature-dependent sex determination (or TSD) is different from most other reptiles.  For tuatara, incubating eggs at higher temperatures (over 22°C) produces males, while lower temperatures (under 21°C) produce females.  In other reptiles with TSD, you generally either get a pattern of females being produced at high temperatures and males at low temperatures, or females being produced at both high and low temperatures, and males produced at intermediate temperatures.

Tuatara hatchling

The weird ways of reptile reproduction

Two studies on reproduction in reptiles have made me go “wow, thats cool” this week.

A simple change determines male vs female organ development in flowers

Gene duplication is a  major source of genomic novelty for evolution to work on.  When genes duplicate, the extra copy of the gene is often redundant – it might degrade and become a pseudogene or take on a completely new function.  Alternatively, the function of the original gene might become partitioned between the two duplicates in a process known as subfunctionalization.  An excellent example of this has recently been reported in the genes that control male and female organ development in the flower, and it’s (almost) all down to a single amino acid change between the duplicate genes.

Development of male and female reproductive organs in flowers is controlled largely by a group of genes called MADS-box transcription factors. Different versions of these transcription factors (known as A, B or C function genes) are expressed in different parts of the developing flower, acting either alone or together to produce sepals, petals, stamens (male) or carpels (female)*.

Much of what we know about flower development comes from studies on two “model” plants – Arabidopsis (rockcress) and Antirrhinum (snapdragon).  In these species, and in many other flowering plants, the MADs-box C-function gene that controls the production of carpels vs stamens has duplicated. In Arabidopsis, one of the copies (called AG) makes both male and female organs, but the other copy has taken on the completely new function of making seed pods shatter (and is appropriately called SHATTERPROOF).  However, in Antirrhinum both copies still play a role in sex organ development: one copy (called FAR) makes only male parts, while the other copy (PLE) makes mainly female parts but also has a small role in making male parts.

Thus in Antirrhinum, the function of the original gene (making both male and female parts) has almost been split between the two duplicate copies.  In a study published online in PNAS last week, researchers at the University of Leeds, led by Professor Brendan Davies,  found a surprisingly simple difference in the two copies has led to their profoundly different roles.

Tuatara tuesday – an iconic parasite for an iconic species

As you might expect from an animal that is so evolutionarily distant from its nearest relatives, the tuatara also has some unique parasites to call its own.  One of these is the tick Amblyomma sphenodonti (sometimes also called Aponomma sphenodonti), pictured here.

Tuatara ticks Amblyomma sphenodonti

Like many ticks, A. sphenodonti are host-specific, spending all three of their life stages feeding on tuatara but dropping off into the soil in between stages.

So why should you care about tuatara ticks?  Well, these ticks are evolutionarily distinct in their own right, and are actually quite rare – far rarer than the tuatara themselves.