To have real passion for one's work is a wonderful thing. And there are few people more passionate than the biologists who strive to preserve biodiversity across the developing world. Many are prepared endure physical privations, infectious diseases, low pay and threats of violence, all in the name of conservation.

But passion can sometimes distort judgment. Just as starry-eyed lovers may be blind to one another's faults, a true believer in any cause can ignore uncomfortable facts that conflict with its goals. That is why the motivations and actions of conservation biologists who are working in Myanmar, with the blessing of its brutal military regime, merit close scrutiny.

In the past, such scrutiny has been uncomfortable for some of the individuals concerned — most notably following the 1997 publication of an article in The Observer, a UK newspaper, entitled ‘Save the rhino, kill the people’. This linked such venerable bodies as the Smithsonian Institution in Washington DC and the Wildlife Conservation Society, based in New York, with abuses of human rights in the southeast Asian nation formerly known as Burma.

The biologists who were singled out for criticism in that article argue, with good cause, that it misrepresented their efforts. And it is apparent from a News Feature on page 870 of this issue that they are working with clear consciences, despite having to engage on some level with the military regime if they are to achieve their goals.

Yet it is important to ask whether the distorting lens of passion has come into play. The imminent threat to Myanmar's biodiversity is not in doubt, nor is the desire of Burmese conservationists for foreign assistance. It is also good to hear that some biologists working in Myanmar have sought the views of ordinary Burmese people.

But some statements do give cause for concern. Attempts to justify engaging with a government guilty of atrocities by arguing that other regimes are just as bad are not compelling. The suggestion that Burmese exiles have exaggerated the abuses in Myanmar is discomforting, as is the notion that conservation biologists need to use ‘charm and guile’ to convince suspicious politicians back in the United States that they are not abetting the Burmese junta.

These may just be poorly chosen words. But it is hard not to wonder, on hearing the stories of those working in Myanmar, whether some conservation biologists are prone to rush to the aid of threatened biota first, and to wrestle with the wider political and humanitarian implications only later. If that's the case, it is a dangerous tendency. As any psychologist will tell you, the human mind is adept at conjuring up post hoc justifications for a course of action that has already been decided.

We should also heed the lessons of history. Today it is widely accepted that effective conservation requires the involvement of local people, and should bring them tangible benefits. But the annals of conservation are littered with instances of people being seen as obstacles that must be removed to make way for parks and reserves. This isn't even limited to undemocratic countries: in the United States, decades ago, conservationists pursued projects such as the Shenandoah National Park in Virginia, whose creators portrayed local mountain farmers as backward and hounded them off their land.

Given this legacy, conservation biologists have a responsibility to ensure that their efforts do not conflict with local peoples' rights, or lend legitimacy to regimes that have dismal human-rights records. This doesn't mean that they shouldn't work at all in countries such as Myanmar. But they should set out for their field sites with their eyes wide open, having researched the humanitarian issues and engaged with parties who may not share their view that conserving biodiversity is the overwhelming priority for the region in question. That will build more confidence that saving the rhino doesn't require unacceptable compromises on human rights.