December 14, 2017

Conserving Water— One Turtle Pond at a Time

 

PHOTO BY ROSI DAGIT

Conserving Water— One Turtle Pond at a Time

“Turtle Incident Command Center,” from left, Capt. Jeff Audet, Delmar Lathers, Ken Widen, Susan Nissman, Hud Floyd, Todd Garvey, Jayni Shuman and Cabot Spiegelman.

Water shortages and climate change are here.

We read stories with detachment while sipping our morning coffee, made with water. When you turn on the tap, water comes out. On a daily basis, most of us are well insulated from the realities of increasingly limited water resources and drought. Until we are not.

My complacency was recently shaken and has caused me to think hard about how we can tackle the problems of allocating limited water resources, maybe one turtle pond, one frog breeding puddle, or one steelhead creek at a time.

Although Southern California has historically experienced multi-year droughts, the combination of the natural variation in precipitation, the subtle yet real increases in temperature associated with global warming, and the competition for scarce water resources have all collided at the turtle pond and in Topanga Creek this summer.

For the past two years, the man-made pond that the turtles rely upon for food and mating has been totally dry. That means that more than 200 turtles have been competing for limited food resources in the small year-round groundwater-fed refugia pools. For the first time in 13 years of monitoring, only 52 meters of water was available out of the 500-meter reach we monitor each spring in Old Topanga Creek. Our tadpole and frog numbers were the lowest since we began counting in 2000. Flows in the main stem of Topanga Creek have been so low that we can barely measure them.

TURTLE INCIDENT COMMAND TO THE RESCUE?

Drought conditions restrict habitat and movement of our fish while providing perfect conditions for an exploding population of invasive red swamp crayfish. Realistically, we can do nothing but wait for the rains to come. But with a hydrant nearby, adding water to the turtle pond seemed possible.

Turtles have been around for 220 million years, surviving many geological and climactic changes, but they are also vulnerable to fast shifts in environmental conditions due to slow reproduction rates and restricted migration ability. It seemed that we should be able to figure out a way to help them through this tough stretch.

PHOTO BY JAYNI SHUMAN

Conserving Water— One Turtle Pond at a Time

Hatchling turtle June 2013

In early May, I was at a meeting with LA County Forestry Chief Kevin Johnson. He kindly did not laugh at me when I asked if the Fire Department ever did practice helicopter water drops. After a brief discussion, he said he would think about how it might be possible to get water to the pond located a half mile from the road. From there, the idea caught on, with Paul Edelman of the Santa Monica Mountains Conservancy and Susan Nissman from Supervisor Yaroslavsky’s office jumping in to help coordinate.

Susan worked with Maria Grycan, Community Services Representative from LA County Fire, as well as with Eleni Hailu and Claudio Funes from LA County Water District #29 to coordinate reusing the water normally used to flush the water tank lines. Donations to the RCDSMM Turtle Project covered the extra water costs. Local Topanga Fire Station 69 staff did a site visit to scope out the logistical challenges. What a group effort!

Based on the calculated area of the deepest portion of the pond and some shovel tests to see how far down the water table was, we estimated that 5,000-10,000 gallons of water could make a difference.

The goal was to create a pool about six inches deep that would stand for several days, providing mating habitat and potentially additional food resources.

On the morning of June 7, Captain Jeff Audet and his crew from Station 69, including Todd Garvey, Cabot Spiegelman, Alex Avedissian and Engine 269 call firefighters Hud Floyd, Chris Whalley and Ken Widen arrived at the site. Setting up the layout for the hoses and where to stage the engines to provide sufficient pump rise was a fun hose management training opportunity.

Greg Naobantian from Water District #29 prepped the hydrant and prepared a de-chlorination dissipater for the end of the hose feeding the pond. Topanga Creek Stream Team members Jayni Shuman and Delmar Lathers walked the fire road in front of the engines to make sure no critters were smashed.

The “Turtle Incident Command Center” went into action. Water gushed into the sandy bottom at the edge of the pond and disappeared into the parched soil. Gopher tunnels sent more water underground. Two hours and 20,000 gallons later, barely an inch of water was covering the small patch of wet earth dammed by call firefighter and Topanga Creek Stream Team member Ken Widen.

Clearly, we needed more water. MUCH more water. But even the kind offer of 60,000 gallons, enough to fill three average backyard swimming pools was probably not sufficient.

WE NEED RAIN, LOTS OF RAIN

The naïve experiment we tried failed to produce the desired result, but we did learn some important lessons. Clearly, the turtles are stressed this year, and we don’t really know how many years of drought it will take to extinguish the last functionally reproducing remnant population in the Santa Monica Mountains.

We do know that each year increases the risk and makes the remaining turtles that much more vulnerable. Turtles confined to small refugia pools with no opportunity to safely disperse to other suitable habitats have a real problem. In Topanga, refugia pools are few and far between, at least half a mile apart and require crossing busy roads.

On Earth Day, turtle lover Ken Kaufman was driving along Old Topanga Canyon Road when he saw a lone turtle trying to cross the road. Watching it almost get run over, Ken stopped, picked it up and called me. The turtle was an adult male (#36) we tagged in 2002, out on walkabout, searching for water and a mate. Ten years later, this turtle showed little evidence of growth and our research shows that the southwestern pond turtles in the Santa Monica Mountains are generally smaller than those found in areas that have more water available.

When there is little rain and higher temperatures, the first-year survival rate of hatchling turtles emerging from eggs is bleak; competing with adult turtles for a limited food supply in small pools allows for little growth.

In Oregon, researchers found that it took an average of 49 days for baby turtles to make their way to water after emerging from their nests. Given the gauntlet of predators waiting to munch on tasty hatchlings and waterless pools in the drainages, it is remarkable that we observed seven babies this spring.

The combination of habitat loss, increased predation and edge effects associated with fuel modification and development intruding into the wildlands, has resulted in a marked decrease in southwestern pond turtle groups.

In 1986, the Southwest Herpetological Society documented turtles in 30 locations throughout the mountains. A study we did for the National Park Service in 2009 found southwestern pond turtles in only eight of those locations and only three had more than five individuals. The Topanga turtles are the only population remaining that has a balanced distribution of adult males, females and juveniles characteristic of a healthy population.

Over half of our turtles are adults that are at least 12 years old. Many have already survived the 1993 wildfire, spent dry years aestivating under the chaparral shrubs, gorged on tadpoles and other goodies when the rains came, and reproduced during the few wet years.

Many of the adults have shells damaged by run-ins with coyotes, raccoons, ravens and dogs, to list just a few of their potential predators.

Southwestern pond turtles can live for 30-40 years, and become sexually mature in 2-5 years. Mating takes place in the water, and females lay between 4-11 eggs in underground nests. The eggs incubate over the summer and babies hatch out in the fall, but don’t emerge from underground until the spring rains soften the earth. When no rains fall, the hard dry soil makes it very difficult for the babies to dig their way out.

Increased summer temperatures, combined with changing rainfall patterns have been documented in Los Angeles by a recent UCLA study.

Predictions for the future suggest that the hot months will warm faster and there could be up to four times as many days when the thermometer tops 95 degrees. Climate models suggest that we could experience up to a 4-degree increase in average temperature by 2050.

Few individual turtles can make the physiological, behavioral or ecological adjustments needed to adapt to shifting climate impacts to their habitat that fast.

If we need to recruit approximately 40 percent of the turtle hatchlings into the population in order to keep it healthy, and drought reduces the number of females laying eggs as well as the number of hatchlings surviving their first year, then we are faced with few good solutions to keeping the population viable, all of which are expensive.

Lining the pond to help it hold water, paying for importing the water, and then actually getting the water into the pond are all costly, but would at least allow the turtles to continue to live in their natural habitat. Capturing turtles to start a breeding-and-rearing program— such as is being done at the San Diego Zoo—would protect the genetic lineage of this population, but at the cost of taking them from the wild.

I WANT TO DO SOMETHING!

Clearly, the simple idea of putting water into the pond was not really that simple. The experience left me depressed. As a scientist trying to make sense of our local ecology, I hate the idea that within my lifetime native turtles could disappear from the mountains that have been their home for thousands of years. How much more can they take?

As a resident who cares deeply about the plants and animals with whom I share my home, I realize, it all comes down to the choices each of us makes.

What behavioral changes are we willing to make to reduce our carbon footprint and conserve water resources? How can we make the turtle pond more sustainable and reliable? How much will it cost? Who will pay for it? How much are we willing to pay to secure a future for our native turtles? How many species are we willing to push to extinction before we act? I don’t pretend to have the answers, but I do know that if we collectively decide that the turtles, frogs, fish and other critters that live in the Santa Monica Mountains are important to us, we need to get our act together. Climate change is real and the effects are hitting us now.

It is now time for thoughtful conversations about how decisions will be made and develop the guidelines needed to ensure that planning and policy decisions focus on identifying potential options to develop a framework for responding effectively to the impacts facing our local flora and fauna.

Tackling the effects of climate change one turtle pond, one creek at a time is daunting. Not taking any action is unthinkable.

So, I am back to the drawing board, and welcome your thoughts on how to solve the problem of not enough water for turtles. And soon, maybe us. Contact Rosi Dagit at Oaksrus@verizon.net.