On July 25, the state Endangered Species Recovery Committee ap- proved an amended Habitat Conservation Plan for Auwahi Wind Energy, LLC’s 24-megawatt wind farm at Ulupalakua Ranch on Maui.
If the plan also receives approval from the Board of Land and Natural Resources, the facility will be authorized to kill or injure 140 endangered Hawaiian hoary bats over the course of its incidental take license, which expires in 2037.
The company’s original plan and take license, approved in 2012, allowed the facility to take only 21 bats. By the end of 2016, however, the wind farm was estimated to have directly and indirectly killed as many as 38. By June 30, 2018, that number had grown to 46.
To minimize its bat take, Auwahi ex- panded its practice of slowing its turbines during low wind (known as low wind speed curtailment or LWSC). It had already instituted a practice of starting turbines at night only when wind speeds exceeded 5 meters/second. Starting in 2018, for the months of August through October, that minimum wind speed, or cut-in speed, was increased to 6.9 m/s.
Historically, 78 percent of observed fatalities at the site occurred during those months. Based on reductions in bat take seen on the mainland with a 6.9 m/s cut-in speed, Auwahi’s regime would result in an estimated 59 percent reduction in its take rate, the plan states.
However, because it’s unclear how much the 6.9 m/s cut-in speed will reduce take of Hawaiian hoary bats, the HCP assumes the LWSC regime will only reduce take by 30 percent.
An earlier draft of the plan estimated that there were 7,200 bats on the island, but after receiving some criticism from the ESRC about the method used to arrive at that number, Auwahi switched to an approach similar to the one used for the Kawailoa wind farm HCP amendment (see cover). The resulting estimated population range is now 1,400 to 5,200 bats.
Assuming that Auwahi and the two Kaheawa wind farms on the island take as many as 11.4 bats per year, their combined impact would not endanger the island’s population, the plan suggests.
“There is no published or reported information which suggests that either the Maui or statewide population is decreasing,” it adds.
Even so, Auwahi plans to implement mitigation measures as soon as the plan is approved. It’s already selected a 1,752-acre area that “consists primarily (more than 95 percent) of sloping open grasslands, interspersed with gulches, and a few forested patches and hedgerows,” the plan states.
To enhance foraging and roosting habitat, the company will plant more hedgerows, using native vegetation, on the pasture lands, and add water features.
The hedgerows and water sources will be located near day roosting habitat so the bats don’t have to expend as much energy traveling between foraging and drinking areas and day roosting habitat.
If and when Auwahi’s take exceeds 66 bats, the company will initiate Tier 5 mitigation measures (i.e., planting native trees, adding water features, removing invasive species) at Kamehamenui Forest, which is proposed for acquisition by the Department of Land and Natural Resources. If the take exceeds 106 bats, Auwahi will be required to conduct Tier 6 mitigation in the forest, which is located on the north slope of Haleakala.
Assuming it takes 20.3 acres to mitigate for each bat taken, “Auwahi Wind would improve 690 acres of habitat in Tier 5 and 508 acres in Tier 6,” the plan states.
20 vs. 3,000?
At the ESRC’s meeting on July 25, Auwahi’s Marie VanZandt reported on all of the tweaks the company made to its draft in response to comments from the ESRC and others. The changes include a commitment to adaptive management of its LWSC scheme and to acoustic deterrents if its LWSC strategy fails, an expanded section on the net benefit of mitigation, an acknowledgement of ESRC bat guidance recommendations, and the incorporation of a new research project: a one-year, landscape-scale bat occupancy study on leeward Haleakala.
She said that Auwahi has found that more than 90 percent of bat activity occurs at the site during the first six hours of night, that 84 percent of bat fatalities occur between May and October, and that more bats are killed at turbines 1-4 compared to turbines 5-8.
If Auwahi determines that the current LWSC approach needs improving, it may expand the months during which cut-in speed is 6.9 m/s and/or extend the LWSC curtailment nights for turbines 1-4.
With regard to the acoustic deterrents, VanZandt said she was interested in seeing the results from those that were implemented at the Kawailoa wind farm on O‘ahu earlier this year. She said she was optimistic, but hoped they won’t negatively impact other wildlife.
Committee member Loyal Mehrhoff said those were nice additions to the plan, but added that he was still concerned about Tiers 5 and 6 and the use of 20 acres/bat as the basis for mitigation efforts. Forty acres — which is what is called for in the committee’s bat guid- ance document — is more appropriate, he said.
He pointed out that a recent study by H.T. Harvey & Associates of bats on Maui found that they spend 50 percent of their time foraging in areas that have an average area of 3,000 acres (see article on Page 5 of this issue). And the plan didn’t even mention this, he noted.
Member Kawika Winter wanted more than just a mention, but a “justification of why you don’t want to use it.”
While H.T. Harvey representatives did give the ESRC a presentation on its work in January, VanZandt said there is no formal report on the results.
“From the standpoint of the ESRC, we’re supposed to be using the best available science. This is the best available science. We’ve known about for eight months. [We] need to know why applicants chose to ignore it,” Winter said.
“Just how, if at all, it changed their mitigation strategy,” member Michelle Bogardus added.
“I see pathways forward. I just don’t want to pretend it doesn’t exist,” Winter said.
By incorporating some kind of reference to the work, “it makes it appear you looked at the research. … It should be on peoples’ minds and should help inform the adaptive management process,” Mehrhoff said.
VanZandt committed to incorporating a reference to the H.T. Harvey study and to describe “how it fits into this broader picture.”
In addition to objecting to the 20 acres/bat standard being used for mitigation, Mehrhoff also said he thought the plan’s schedule for evaluating take minimization measures was insufficient.
Instead of once every five years, he preferred once every three years.
As written, “you won’t get to deterrents until 2030,” he complained.
VanZandt explained that the plan included regular check-ins that occurred at sooner intervals, and those 5-year evaluations would only hold if data in the interim suggested that everything was fine.
The committee went round and round on the plan’s timeline for a while.
At one point, Bogardus said, “We’re going down a crazy rabbit hole.”
But Mehrhoff, former head of the FWS Pacific field station, was adamant that the plan be clear on what’s required and when.
“It’s happened more than once: people leave and it goes back to the words in the HCP. … I’ve been on this train before. Not with you guys. It comes down to what’s written in there and what’s required. … I think [five years] is too long to wait when you’re talking about 130 bats,” he said.
Division of Forestry and Wildlife administrator Dave Smith, who chairs the committee, favored the five-year interval. If evaluations occurred every three years, there would be less confidence in whatever data was collected in that time because it’s so short, Smith argued.
In the end, the committee approved the plan with the inclusion of a reference to the H.T. Harvey study and a “contextual clarification around the adaptive management dates.”
Mehrhoff was the only dissenter.
— Teresa Dawson