FRANCESCA Osowska has some pretty big challenges to wrestle with in her new job as chief executive of Scottish Natural Heritage. Should we reintroduce wolves and lynx to Scotland? Should the controversial culling of wild hares continue? Can we save the capercaillie? But none of the critical questions about Scotland's iconic species quite compares to her days wrestling with one of the big beasts of politics: the former First Minister Alex Salmond.

The subject of Mr Salmond crops up while Osowska and I are talking about her impressive career in government and the civil service. Osowska, who's 47, has been, among other things, an economist at the Scottish Office, director for the Commonwealth Games in Glasgow, and head of the UK Government in Scotland. But when I ask her what the lowest point of her career was, she mentions her time as principal private secretary to Alex Salmond from 2007 to 2009.

She then says she's going to have be very careful about what she says next, which is not a surprise from Osowska. After a long career in the civil service, the way she talks can be a bit jargony, slick and ultimately aimed at avoiding answering the question - a bit Sir Humphrey. She pauses for a bit then decides on the words she wants to use.

"There were times when I was working as principal private secretary to the former First Minister Alex Salmond which were challenging," she says, with a heavy emphasis on the word challenging. "I would find myself at Bute House at midnight in front of my computer thinking “oh s**t, how am going to resolve this by 8am?” Long hours. Challenging issues. He was also an economist himself so I couldn’t bulls**t him."

She adds that working for Mr Salmond could be fun, and there's no doubt that, after years in the civil service, Osowska is used to working in stressful environments at the highest levels. Indeed, if anything, her new post at Scottish Natural Heritage ramps up the stress even further. When she was head of the UK Government in Scotland, she ran a relatively small department of 70 people, but SNH is ten times that size, with a budget of £49million, and, as head of the organisation, Osowska is responsible for some of the most complicated and controversial cultural, and environmental issues facing modern Scotland.

One of the most immediate is Brexit. The vast majority of the current law on the Scottish environment originates from the European Union, and there is concern among wildlife and environmental groups that leaving the EU could mean a dilution of the protections for wildlife - a concern which was only increased when the Commons rejected a proposal to bring into UK law Article 13 of the Lisbon Treaty which explicitly recognises animal sentience. The Scottish Government has also expressed a concern that there could be a "grab" over environmental law, meaning the returning powers go to Westminster rather than Holyrood.

However, Osowska believes the worries are misplaced. "The aim of the EU Withdrawal Bill is to ensure that those laws and directives currently existing at EU level are transposed into either UK or Scottish law and what that will mean, and what Roseanna Cunningham, the environment minister, has been very clear about, is that the level of environmental regulation will be the same the day after the EU exit as it was the day before."

But what if there's a power grab by Westminster? "Even if there’s a grab and those powers are at a UK level, they should still be the same and still apply in Scotland. Roseanna Cunningham has said she doesn’t want to see a lessening of standards and I would agree with that. I’m sure you could find a constitutional lawyer who would tell you that is theoretically possible but I can’t envisage a situation where there’s a void in terms of environmental regulation."

Look closely at that answer at you can see the different influences at work on Osowska, often pulling in different directions. Scottish Natural Heritage is a government agency but its founding aim is to protect the country's natural heritage, and that can create conflicts. According to Osowska, the aim will always be to implement government policy but to do it while taking into account local differences and giving honest advice to the government. Yes, there are influences pulling in different directions, but then, with a life and career like hers, Osowska is used to it.

She grew up in the ex-mining town of Whitehaven in Cumbria, and as a girl, was pretty academic; she was also the type that always finished what she started and says she's still like that, which is why, away from work, she is so good at triathlons. For 14 years after moving to Scotland in 1997, Osowska competed as a triathlete at the highest level and she still takes part in them. They keep her in all-round condition, she says, but running, swimming and cycling round the country also deepened her love for the thing she is now paid to protect: the Scottish landscape and environment.

She reminds me that she is only in Day 15 of the job but she's already starting to think about some of the big issues: rewilding for example, as well as managing (and culling) deer, squirrels and other species and protecting others.

On rewilding, it would be fair to say that Osowska is cautious. She has seen some of the evidence, including the positive effect that reintroducing wolves has had on the biodiversity of Yosemite National Park in the US, but she says she is aware of the downsides.

"There are competing interests," she says. "I've seen the film about the wolves in Yosemite and it’s amazing but can you imagine the reaction if all of a sudden a family of wolves popped up in the Highlands? We're a small country but what we can do is the research and understand the different interests. We're supportive of some rewilding but on the basis of a very deliberate programme of listening to views and looking at the evidence, and understanding the implications."

On culling certain species, Osowska is more bullish. Can she, for example, defend spending £8million over the last 10 years killing grey squirrels even though the red squirrel is nowhere near endangered in Europe? She has a go. "We're ensuring that we're able to promote our native species and sometimes that means taking action on invasive species," she says. "That means we do kill things – deer, and squirrels and geese. We have contracts with organisations to manage numbers and that has to be seen in the overall context of promoting biodiversity in Scotland and trying to protect our native species. And there are a lot of grey squirrels, there aren’t as many red squirrels – that's the balance that we’re trying to manage."

Osowska also defends the even more controversial culling of wild hares. Thousands of wild hares, which are a protected species, are being culled on grouse moors and, according to some conservation groups, this has raised the risk of extinction in some areas. However, Osowska says the population is not at threat and does not support the idea suggested by some groups that there should be a temporary ban on culls until more research can be done on the effects.

"I think we do have quite a lot of evidence in terms of the population of mountain hares across Scotland," says Osowska. "In localised areas, there may be concerns about the population but again this is about managing an overall species. We do have a lot of evidence which suggests that the overall population is not under threat."

Where there clearly is a long-term threat is to the capercaillie, whose populations in Scotland have fallen 50 per cent in the last two decades. To make matters worse, because of cuts to its budget, Scottish Natural Heritage has had to scale back its efforts to protect the bird and focus on one of its last redoubts: the Cairngorms.

"In terms of resources, and this I common across the public sector, this is the world in which we live, there is a resource squeeze. Our staff numbers have fallen by 25 per cent over the last six years because of budget cuts. We have looked internally to make as many efficiencies as we can and we’ve also had some impacts on project funding.

"But we do need to prioritise different programmes so the capercaillie issue is more pronounced in the Cairngorms so I think that’s a sensible use of our resource and public funding to concentrate on that area." But is she concerned that means there could be less long-term chance of protecting the capercaillie? "I don’t think we would have the evidence to suggest that."

As for another of Scotland's threatened species (and it turns out Osowska's favourite) - the Scottish wild cat - the chief executive is open to new ideas, such as bringing Spanish wild cats into the country to help protect the native population. She also says she is keen to get out into the Scottish outdoors as much as she can, running, swimming, cycling and thinking. It's about putting one foot in front of the other, or one pedal stroke, or one arm stroke, she says, but above all it's about finishing because when she was a civil servant she rarely did. "You have a working group, then another working group," she says. "Civil servants never bloody finish anything."

Best advice.

Listen more than talk.

Favourite film

Nikita, the original French film. I just loved the character.

Favourite music

Arcade Fire. I find it quite melodic, all the organs; also Inspiral Carpets from the 80s. That was organs as well.

Last Book Read.

A Man Called Ove by Fredrik Backman. It's about a cantankerous octogenarian who is at war with the world but he’s won over by new people coming into his street.

Best trait

Decisiveness.

Worst trait

Decisiveness. I now recognise it and give myself a bit of a talking to. I like clarity: here’s a decision, let’s get on with it. But you need to know when to be flexible.

Ideal dinner party

Barack Obama has to be there, as well as Chrissy Wellington, the British triathlete, and Noel Gallagher for a bit of bad boy spice.