The drought has caused a third of the tule elk that live in the fenced enclosure on Tomales Point to perish from malnutrition. The decline is the fourth on record, and it aligns with the boom-and-bust cycle the park service predicted after reintroducing the species to the Point Reyes National Seashore in 1978. 

In 2020, the fenced herd dropped from 445 to 293 animals, while the park’s two free-ranging herds remained more stable. Based in part on six necropsies conducted last year, the park attributed the decline to reduced forage amid abnormally dry conditions. 

“The primary cause of death was malnutrition,” said Dave Press, the seashore’s wildlife ecologist. “Basically, they were not able to get what they needed from the available dry forage on the landscape. Poor health likely made them more susceptible to other health issues, such as parasite loads and the inability to fight off infection. Malnutrition can have cascading effects.”

Of the six elk studied, one had a heavy internal parasite load, and two had ingested a toxic plant suggesting a lack of better forage; all were low on body fat reserves. One effect of these conditions is a lower calving rate and calf survival, Mr. Press said. Twenty-seven calves were found last year, compared to 90 the year before.   

Yet the elk did not suffer from a lack of water sources, a concern long held by activists; last summer, several people took matters into their own hands and illegally brought water into the enclosure. Some organizations have called for the removal of the fence, a move the park is not considering. 

“This is completely devastating,” said Diana Oppenheim, the founder of ForElk. “The 152 elk who died is not from a natural population swing, it is from park policy that keeps wild animals trapped behind a fence without adequate resources… The park service needs to be held accountable to animal cruelty and the unnecessary deaths of the tule elk.” 

Alison Hermance, a spokeswoman for WildCare, said the group began pushing the park service to investigate water and food supplies in 2013. “Keeping captive animals necessitates providing sustenance,” she said. “What is currently happening with adequate water but not proper nutrition is not acceptable to us.”   

There are only two other fenced tule elk herds in California, and Kristin Denryter, the elk and pronghorn coordinator for California Fish and Wildlife, said they are occasionally brought food and water. But she added that the herds are much smaller and do not have the same potential for growth. A herd in Tupman managed by state parks has just 10 animals; another in the San Luis National Wildlife Refuge has around 50 individuals, which are periodically translocated elsewhere to keep the population level. Translocation is not an option for elk in the seashore, since they carry Johne’s disease.

Ms. Denryter said the park service would be doing the ecosystem a disservice by intervening to provide supplemental forage. Such interference would artificially increase “the number of elk more than the landscape could support, leading to a more vicious cycle,” she said. 

In general, tule elk populations in California are thriving. “This one declining population is not a threat to the species,” Ms. Denryter said. “I do think it helps raise awareness about the seriousness of drought for wildlife generally. We are likely to see more severe droughts and more drought periods and this puts that right in front of us.”

The seashore’s fenced herd has contracted three times before. The population peaked in 2007 at 585 individuals. Drought years starting in 2013 brought numbers down to 356, and to 286 in 2014. The 2,600-acre enclosure has a recommended carrying capacity of 350 individuals, according to the park’s guiding document on the elk, a 1998 management plan. 

The plan recommends the kind of passive population control that has been the park’s strategy. Should the population grow beyond available food resources, the plan predicted there would be “a series of modulated swings of population growth and decline, a process that has been called natural or self-regulation, as it does not involve the limitation of elk numbers by active reduction on the part of wildlife managers.”

The plan recommended the park service establish a free-roaming herd, which it did. The herd has since become two, concentrated at Limantour and Drakes Beach, and they have slowly grown, posing conflicts with ranching operations.

As part of the impending general management plan amendment, the park service intends to keep the Drakes Beach herd at 120 individuals, a target that will require culling around 18 elk a year. There is no population target for the Limantour herd.