	Introduction

The federal Endangered Species Act (ESA), along with its state counterparts, has long been a major flash point in debates over government interference with property rights. Second, given that restrictions on land uses and other property-related activities are imposed under the ESA, to what extent does the Takings Clause of the Fifth Amendment demand compensation of the property owner? Sections I and II of the report give background: respectively, the ESA features pertinent to the act's impacts on private property and ESA-relevant principles of Fifth Amendment takings law. Of the 18 decisions reviewed, only one, Tulare Lake Basin Water Storage District v. United States , found a taking, and as discussed that decision has been undermined by a later decision of the same judge that appears to have survived appeal. However, two other cases have yet to be finally resolved and thus may or may not ultimately find a taking. However, this defense has yet to be addressed in an ESA-based takings decision. Physical takings claims are common in ESA cases—the property owner pointing to a required physical diversion of water to supply a fish ladder for a listed species, listed animals whose physical presence on his/her land must be tolerated, the consumption of livestock by listed predators because the livestock owner was barred by the ESA from taking stronger measures against the marauding animals, or the temporary presence on the owner's property of federal investigators. The landowner's taking claim based on the required mitigation of his development's impact on the salamander is unripe. They assert a Fifth Amendment taking. V. Reductions in Irrigation Water to Preserve Instream Flows

Reduction by United States in irrigation water that water district was allowed to divert from river: Casitas Municipal Water District v. United States , 543 F.3d 1276 ( Fed.
The federal Endangered Species Act (ESA) has long been one of the major flash points in debates over government interference with property rights. This report outlines the ESA provisions most relevant to the act's impacts on private property and surveys the major ESA-relevant principles of Fifth Amendment takings law. The Takings Clause of the Fifth Amendment promises "just compensation" when government actions "take" property.
The report then summarizes the court decisions on whether particular government actions (or inaction) based on the ESA "take" private property under the Fifth Amendment. The cases to date address several kinds of ESA impacts on private property: (1) restrictions on land uses that might adversely affect species listed as endangered or threatened, and mitigation conditions to offset the impacts of development; (2) administrative delays; (3) reductions in water delivery or allowable water diversion to preserve lake levels or instream flows needed by listed fish (currently the most active area of ESA takings litigation); (4) restrictions on the defensive measures a property owner may take to protect his/her property from listed animals; and (5) restrictions on commercial dealings in listed species.
To date, only one of the 18 ESA-based takings cases disclosed by research, Tulare Lake Basin Water Storage District v. United States, has found a taking. However, two cases, Casitas Municipal Water District v. United States and Klamath Irrigation District v. United States, have yet to be finally resolved and may or may not result in holdings that takings occurred.