Good news about the environment is rare these days, but in Tanzania there are signs that local wildlife conservation efforts can effectively protect the natural resources that provide the lion’s share of revenue for the economy. Eco-tourism is Tanzania’s largest economic sector and biggest dollar earner for this developing nation, but wildlife populations have suffered in recent decades from poaching and clashes with people involved in other economic activities such as farming and mining. The good news comes from a new study that found community-based wildlife conservation can quickly result in clear ecological success, with the largest and smallest species being among the winners.