Please answer a question about the following article about Endangered Species Act:

Growing scientific recognition of the role of private lands for endangered species recovery and the landmark 1981 court decision in Palila v. Hawaii Department of Land and Natural Resources both contributed to making Habitat Conservation Plans/ Incidental Take Permits "a major force for wildlife conservation and a major headache to the development community", wrote Robert D.Thornton in the 1991 Environmental Law article, Searching for Consensus and Predictability: Habitat Conservation Planning under the Endangered Species Act of 1973.

What 1981 court decision added to the power of HCPs and ITPs for conservation?
Palila v. Hawaii Department of Land and Natural Resources