(CNN)One of Africa's largest wildlife preserves says it's been a year since it found an elephant that was killed by poachers.
The last time an elephant in the Niassa Reserve was recorded killed by a poacher was May 17, 2018, according to the Wildlife Conservation Society, which assists Mozambique's government in managing the reserve.
The drastic decline in poached elephants is credited to a new rapid-intervention police force, an increase in surveillance by helicopters and Cessna aircraft and tougher legal action, said Joe Walston, Senior VP of Global Conservation Programs at WCS.
"Any one of those things alone isn't going to be successful, which is why it has taken so long to be able to get us to a point where we've been able to get poaching under control," Walston told CNN.
The Niassa Reserve is in a remote region of northern Mozambique, where thousands of animals have been killed in recent years.
The rapid-intervention police force is better armed than the reserve's normal rangers and is empowered to arrest suspected poachers. Walston said that the ability to make arrests is important to deter and prevent poachers from coming to the reserve.
There is a massive amount of habitat available in Niassa, with land spanning about 17,000 square miles -- which is larger than Switzerland. Because of this, it is one of the few places left in Africa capable of supporting a large population of elephants.
But high levels of poaching between 2009 to 2014 cut the number of elephants from about 12,000 to a little over 3,600 in 2016, according to an aerial survey.
From 2015 to 2017, efforts to stop poaching decreased the number of killings to about 100 animals a year. History has shown that the elephant population has the ability to bounce back quickly after numbers dip low. Walston said conservationists saw this happen after a poaching crisis in Africa over a decade ago.
"Once it was got under control, the elephants rebounded q