Imagine spending hundreds of millions of dollars on a project and not being able to demonstrate whether or not you’ve achieved what you set out to.

Such is the case for programs aimed at helping Australia’s threatened plants and animals, which the government has boasted it is funding to the tune of $255m.

Yet it turns out we don’t actually know to what extent this money is benefitting threatened species at all.

In a Senate estimates hearing on Monday, the Department of Energy and the Environment confirmed it does not audit projects designed to protect threatened species. “Of threatened species in general – no,” the department’s first assistant secretary Kylie Jonasson told the hearing.

“But in terms of any probing of program expenditure, we do have a range of arrangements in place to ensure that the appropriate expenditure occurs consistent with the contract arrangements that we’ve set up.”

But no big deal. It’s just the environment, right? Australia’s been kicking it in the guts for years.

Australia’s biodiversity is declining at such a rapid rate that experts have labelled it an extinction crisis and a “national disgrace”.

Our country has clocked the highest rate of mammalian extinction on earth for the past two centuries – we’re losing one to two mammal species per decade – and we’re not improving.

Scientists who have spent their careers researching and trying to protect Australia’s threatened flora and fauna are pleading for communities and governments to care more about the country’s wildlife, vast amounts of which occur nowhere else on Earth.

And in terms of its publicly stated sentiments, the Coalition government has said multiple times it does care and has singled out threatened species as a key policy issue at the past two elections.

It has installed a threatened species commissioner – which has had success in raising the profile of endangered plants and animals – and says it is funding more than 1,200 projects for their benefit.

But as a Guardian Australia investigation has found, the threatened species credentials of some of those projects are questionable.

Heritage building work, boardwalk construction, weeding, and street tree planting to cool down concrete urban areas – all worthy community projects, but which conservationists and scientists say have limited, if any, long term benefit for species trying to avoid extinction.

In some cases, certain animals and plants don’t even occur at the sites of work apparently set up for their benefit.

The Senate estimates hearing was told on Monday an “administrative error” was responsible for the designation of some of these works as threatened species projects.

If it’s an administrative error, it’s one that has been made routinely in the department’s documents for more than a year until it was publicly called out by experts.

Senators also heard that in assessing the benefits to threatened species of certain projects – which have largely been funded through the government’s Green Army and 20 Million Trees programs – the department relies on information supplied by project applicants.

It then runs the information through its protected matters search tool – a government database that highlights which plants and animals are likely to occur in particular areas.

But there’s been no audit of the works to determine what they have achieved for threatened species.

Senators were told that if there was an expert with information that a species did not occur at a specific site, then they should get in touch with the department.

Officials also said the department did not have a system reviewing the effects and outcomes of all recovery plans – documents that set out steps that should be taken to help individual plant and animal species.

There are 746 of these documents currently and officials said it was likely only a “relatively small” number had been reviewed.

Environment groups, Labor and the Greens have accused the government of overstating what it is spending on threatened species. There are calls for an independent audit of all expenditure to determine precisely what gains the government’s numerous programs are achieving for wildlife on the brink of extinction.

When the government itself can’t articulate how it is tracking it, it doesn’t seem like an unreasonable ask. But perhaps that is caring too much.