Evidence that laws actually work to save (some) endangered species
A study confirms the U.S. Endangered Species Act does actually save species

Scientists in the U.S. have found that marine animals placed under the Endangered Species Act do recover their populations if they are protected.
This is a rare good news story as animals worldwide face extinction due to human activity.
A recent study tracked the health of 31 populations of sea turtles, large whales, manatees and other marine mammals that had suffered severe declines and been listed as endangered. The study showed that 24 populations, which had been protected for at least 20 years, showed increases in abundance. A further five populations showed no further declines, and only two actually lost ground.
This is the first study that has tracked the health of animal populations in U.S. waters after they had been listed as endangered. This is gratifying evidence to show that if laws are put in place and conservation efforts are carried out on national and international scales, animals can come back.
One species that has not done well is the northern right whale, which is down to less than 500 individuals. These whales continue to suffer, particularly from strikes from ships and entanglement in in fishing gear.

The U.S. Endangered Species Act was established in 1973. It has been a major success story. The U.S. Fish and Wildlife Service claims it has protected 99.5 per cent of the species under the law's care from extinction. A study in 2006 suggested that without this protection, an estimated 227 species would have gone extinct. The success is due to a combination of strategies: protection of habitat, managing fisheries and a dedicated recovery plan.
In Canada, endangered species are protected under federal law by the Species At Risk Act (SARA) which has been in place since 2003. When it began, 223 species were on the Canadian list. Now there are 524. This act is joined by the Habitat Stewardship Program, begun in 2000, which is dedicated to protecting critical habitats from development and activities such as road construction.
Enforcement of SARA has been criticized as insufficiently rigorous by some researchers. But according to government documents, more than 2,500 projects have been taken on, providing legal protection for over 191,000 hectares of land and the improvement or restoration of 402,000 hectares of land and 3,200 kilometres of shoreline.

Canada has also established numerous Marine Protected Areas with the goal of protecting 10 per cent of our coastal and marine areas by 2020 in compliance with our obligations under the United Nations Convention on Biological Diversity.
While these laws do offer protection to animals, they themselves are threatened by political pressure. In the U.S., business interests and the Trump administration have lobbied to weaken the power of the Endangered Species Act so protected shorelines can be cleared for resorts and condos, or marine protected areas can be drilled for offshore oil and gas. It is the old battle between the environment and the economy.
While scientists can find evidence for the effectiveness of programs such as the Endangered Species Act, it is really a drop in the bucket in the face of the so-called "Sixth Extinction" taking place currently due to human activity. More species are going extinct than are being protected. It's kind of sad that we have to wait until species become endangered before we think about protecting them. Wouldn't it be better to think of protection at the front end?

The massive declines and extinctions of species worldwide is mostly due to our careless over-exploitation or destruction of habitat. We have a history of trying to scoop every fish we can out of the sea, clear every tree, or dig for fossil fuels without regard to the impact on the overall ecosystem. Now, armed with the knowledge that protecting animals and habitats actually works, perhaps we can approach resource extraction with protection in mind from the start.
Famous conservationist John Muir, who was instrumental in establishing the national parks system in the U.S., summed it up when he said, "When one tugs at a single thing in nature, he finds it attached to the rest of the world."