- Author: Niamh Quinn
Rodenticides continue to come under scrutiny in California due to issues surrounding the potential for nontarget injury to wildlife and pets. While California already has the strictest rodenticide laws and regulations in the country, there have been recent calls to ban all rodenticide applications in the state. Several Assembly Bills (AB 2596, AB 1687, and AB 2422) have been introduced proposing either bans or major restrictions on rodenticide applications.
Anticoagulant rodenticides have been detected in many species of wildlife worldwide; yet the origins, exposure pathways, and effects of these exposures are not well understood. The origins of these rodenticide exposures from point of application to point of acquisition are being studied by a collaborative group from the University of California Agriculture and Natural Resources and California State University, Fullerton.
Second generation anticoagulant rodenticides (SGAR) are important public health tools used for the quick and effective knockdown of rodent infestations in urban areas. Unfortunately, SGARs are regularly detected in many species of wildlife, perhaps because top-level carnivores and birds of prey are thought to prey on rodents that have been exposed to these rodenticides. However, while urban carnivores like coyotes are often found (postmortem) to have been exposed to both first generation anticoagulant rodenticides and SGARs, they are not known to consume rats and mice in large quantities.
To determine what coyotes eat and potential sources of rodenticide exposure, the research group is investigating the stomach contents of urban coyotes in southern California. While the study is only one third complete, stomach content observations have already revealed that coyotes consume more cats than rats, and their preferred mammalian food source is, in fact, rabbit.
The study will continue until the contents of 300 urban coyote stomachs have been examined. The research group will also determine what mammalian species are in the stomach by doing molecular analyses. The group hopes that once they have a clear and accurate picture of the diet of this urban carnivore in southern CA, they will have a better idea about potential sources of rodenticide exposure.
The research group is also investigating how animals interact with nontoxic bait stations in the backyards of Orange County urban residents. With the help of the UC Master Gardeners of Orange County, the research group will examine whether the animals access the bait or physically interact with a bait station in a way that may cause the bait to become dislodged as well as other potential exposure issues. The study is still in its infancy, however, and many animals ranging from mice to bobcats have been detected already. Despite the range of stations visitors, the only animals so far observed to enter bait stations to access the nontoxic bait were rats and mice.
Within urban pest management programs, it is crucial that we determine the potential routes of wildlife exposure to pesticides so that public health can be protected while limiting negative impacts on the environment.
- Author: Carol Nickbarg
- Contributor: Native Plant Subject Group
- Editor: Kamille Hammerstrom
Planning a Wildlife-Friendly Garden
- Observe your garden throughout the year. What types of desirable wildlife are already in your garden? Where in the garden do they appear: plant species/physical feature, shade/sun, feeding/nesting? Do they appear seasonally or year-round? Not all plants (even of the same species) or physical features are alike. For a plant species that thrives in either sun or part shade, one may be more favored than the other depending on the insect, bird or mammal using it. Likewise, birds may not perch on a snag fully exposed to strong winds, but may use the less exposed snag found only a few feet away.
- Research your area. What kinds of plants and wildlife are native to local areas similar to your property (climate, exposure, soil type, topography). Parks (state, county) and local wildlife organizations are wonderful resources, with downloadable lists and profiles of flora and fauna, often sorted by the different habitats found in local wildlands.
- Which wildlife species in your area would you like to see in your garden? Which need support and could benefit from your garden? Which plants and physical features would encourage their presence? Physical features need not be large or require major construction. Numerous small and simple features such as a pile of stones, a bee nest structure, a birdhouse can create benefits greater than the “sum of their parts.” What seems minor to us, e.g., a downed branch, may already be host to beneficial decomposers we can't see and used by other wildlife we can.
- Observe your garden again for undesirable plants, wildlife or features. Choose control methods that will not conflict with your wildlife-friendly goals, e.g., avoid herbicides for weed control, which may also harm desirable plants.
- Select suitable native plants or physical features. As your garden's overall diversity becomes richer, so will its range of potential habitats and wildlife. Make changes gradually, regardless of whether your garden is young, mature or somewhere in-between: introduce two or three native plant species at a time (vary understory height, flower size and shape, bloom time), two or three types of physical features at a time. For young gardens or gardens with low wildlife presence, start by encouraging insects, then move up in phases to birds, reptiles, small mammals as desired.
Other Considerations
Research potential risks to family or pets associated with plants or wildlife you are considering for your garden. We provide the following links for you to research your questions about people, pets, and wildlife, but always check with your physician or veterinarian for the final word on potential risks.
- American Society for the Prevention of Cruelty to Animals (ASPCA)
- Bay Area Lyme Foundation
- Univeristy of California Division of Agriculture and National Resources (UCANR)
Natural Nuisances
Check for unique behaviors when researching wildlife. For example, a seasonal pond may attract the Pacific treefrog (Pseudacris regilla), a favorite of this writer's but admittedly very vocal and very loud: one frog's “serenade” to another may become an unwelcome disruption of peace and quiet.
Governing Agencies
Always consult with relevant HOA, city, county and/or other agencies during your planning phase.
- Physical featuresSyrphid fly feeding on Ceanothus pollen. Syrphid larvae are garden beneficials, feeding on aphids, scales, thrips and other soft-bodied insects. Photo: © Carol Nickbarg.
- Some features or changes (e.g., terracing, drainage) to your garden may require a permit.
- Some features, especially certain water features, may alter the ecology of your property: as plants and wildlife come to depend on the feature, governing agencies or other entities may not allow the feature to be removed later, even if the feature is man-made.
- Plants
- Plant installation or removal: local urban forestry departments or other agencies may have preferred species or “avoid” lists for certain plants in your area; tree or other vegetation removal may require a permit.
Maintaining a Wildlife-Friendly Garden
- Regularly inspect any netting or structures to be sure birds, reptiles, small mammals have not become trapped.
- Regularly maintain birdbaths or other water features.
- Manually remove weeds and invasive plants.
- Practice integrated pest management.
- California Invasive Plant Council (Cal-IPC)
- PlantRight
- The Gardener's Guide to Common-Sense Pest Control: Completely Revised and Updated. 2013. William Olkowski, Sheila Daar, Helga Olkowski. Taunton Press.
- University of California Statewide Integrated Pest Management (UC IPM)
Final Thoughts...
References and Additional Resources
References
- Skippers, Encyclopedia of Life
- Pacific treefrogs, National Parks Traveler
This is the second of a two-part post. To read the first part or check out the rest of the references and resources for this post, visit Part I on our website.
For local inspiration, be sure to attend our 2017 UC Master Gardeners of Monterey Bay Garden Tour on September 9th, 2017. More information about the Garden Tour can be found here.
If you'd like to purchase any of the reference books mentioned, use our AmazonSmile account! It won't cost you anything but we'll get a small donation with each purchase made through our link. Don't forget to subscribe to our blog so that you receive an email notification when a new post goes up. If you have questions, contact us online, by phone or in person to get answers to your gardening quandaries!
/h3>/h3>/h3>/h3>/h3>- Author: John Madsen
- Author: Angela Llaban
The USDA ARS and California State Parks, Division of Boating and Waterways have initiated a study to address concerns that dissolved oxygen may be depleted by plant decomposition under herbicide-treated beds of water hyacinth. Using state-of-the-art miniaturized dissolved oxygen / temperature recording datasondes, the oxygen concentration will be measured before and after treatment of waterhyacinth in channel-side and back-bay areas of the California Sacramento / San Joaquin River Delta, as well as under untreated water hyacinth and in open water areas. Herbicide treatments that will be evaluated include 2,4-D, glyphosate, and imazamox.
The study will be six weeks in duration, and encompass six sites using 25 datasondes. We anticipate that the study will accurately depict the true dissolved oxygen dynamics associated with mats of water hyacinth and their treatment.
This study is conducted in cooperation with DRAAWP, the Delta Region Areawide Aquatic Weed Project.
![DO / temperature datasonde DO / temperature datasonde](/blogs/blogcore/blogfiles/36772.jpg)
![Water hyacinth and water primrose in the Delta Water hyacinth and water primrose in the Delta](/blogs/blogcore/blogfiles/36773.jpg)