Ecological Reserves are established to preserve a location’s natural environment allowing current and future generations of visitors to explore and enjoy the land’s native flora and fauna.  As we work to maintain the beauty and uniqueness of the California coast setting, we also restore and improve the habitats found on the Reserve. 

A project currently on the horizon at the Reserve is to restore native grassland and coast live oak groves that throughout decades were displaced by non-native invasive eucalyptus trees.  The removal of selected eucalyptus groves will enhance habitat for threatened species of amphibians especially the Santa Cruz long-toed salamander and California red-legged frog, while still maintaining other eucalyptus trees that provide important habitat for birds and butterflies. 

This science-based restoration project has been years in the planning and, once started, will take approximately 10 years to complete.  Learn more and see a map of this restoration project below.

Preserving the native environment of California’s central coast involves science, historical research, planning, and plenty of hard work.  On the 1,700 acres of the Reserve, our objective is to protect and preserve the natural habitats that thrive in this area.  Sometimes this means restoring the landscape changed through decades of human use to sustain the native environment of this land.

This map shows the eucalyptus groves that are targeted for removal, as well as the groves that will remain untouched. Click the map for a larger view.

Quick Points on this Project

  • All restoration work conducted by both the Elkhorn Slough Reserve and Elkhorn Slough Foundation is based on science and best land management practices.
  • Eucalyptus is a non-native invasive plant to the California central coast environment.
  • As non-native plants, eucalyptus require and use more water than native plants, often depleting ground water critical for native amphibian survival.
  • Only 13 of 48 acres of eucalyptus are targeted for removal (less than 30% of eucalyptus currently on the Reserve).
  • The acres targeted for removal have been determined to improve/enhance the health of the overall habitat.
  • Eucalyptus groves proving important habitat for nesting birds will remain intact and protected.

Our expected outcomes for this project are:

  • Improved habitat for threatened species of amphibians especially the Santa Cruz long-toed salamander, tiger salamanders, and California red-legged frogs.
  • Return of native coast live oak groves.
  • Return of native California grasslands.
  • Enhanced viewshed, increasing ability to see rare wetland marsh and the main slough channel.

More about Elkhorn Slough and Eucalyptus
Historically the uplands of the Elkhorn Slough National Estuarine Research Reserve were dominated by coastal prairie, coastal scrub, freshwater meadows and coast live oak woodlands. Eucalyptus trees were planted on the property before the 1930s,  for use as timber and, in some locations, as a wind break. Today, the Reserve’s uplands include nearly 50 acres of non‐native eucalyptus trees, spread out over 13 groves. Four of the 13 eucalyptus groves directly threaten native oak woodlands, native grassland, and freshwater ponds known to serve as habitat for listed and special status species, including the endangered Santa Cruz long‐toed salamander and the threatened California red‐legged frog.

Without intervention, these four eucalyptus groves are expected to compromise adjacent oak habitat and to decrease groundwater near ponds, reducing water levels available to keep ponds wet during the amphibians’ breeding period. The end result would be twofold; significant loss of amphibian habitat and the decrease in native biodiversity.

We have proposed removing only these four damaging groves (less than 30% of all the eucalyptus on the Reserve). This restoration effort would protect existing natural resources, as well as allow for oak woodland, scrub and coastal prairie to return. Other eucalyptus groves, one of which serves a bird rookery near the mouth of Elkhorn Slough, will not be affected.

Past eucalyptus removal on the Elkhorn Slough Reserve:
In the 1990s, Elkhorn Slough Reserve staff, volunteers, and work crews removed a 13-acre exotic eucalyptus grove on the northern portion of the Reserve and, in its place, planted thousands of coast live oak acorns and other native plants. Today, an open oak woodland, interspersed with scrub and grassland habitat, is developing in the area.

The same area today:


Restoration and Eucalyptus Research

The Elkhorn Slough National Estuarine Research Reserve bases habitat management actions on the best available science. We recognize that decisions regarding non-native species control or removal are complex and involve trade-offs. Beginning in 2004, the Elkhorn Slough Reserve partnered with other local researchers to study the impacts of eucalyptus on coastal California habitats. This research demonstrated that local eucalyptus groves expand significantly without control, and that groves can have negative impacts on some native plants and animals, while some eucalyptus can also provide habitat for a different suite of birds (Click here). Additional research results are provided on our Coastal Training Program’s pages – click here.

This project balances science-based management to protect and restore oak and freshwater habitat for sensitive amphibians, while preserving other eucalyptus groves as habitat for birds.