This column follows our current overview of biodiversity, which refers to the diversity of all living things (animals, plants, fungi, and microorganisms) and their interactions. Biodiversity has three levels: species diversity, genetic diversity and ecosystem diversity.
Biodiversity refers to changes in a particular plant or animal species as a result of natural or human sexual reproduction, hybridization or mutation.
Genetic variation is an evolutionary process in which organisms gradually adapt to changes in the environment.
Ecosystems provide habitat for organisms that interact with their environment. Ecosystem diversity refers to the diversity of ecosystems in a given area. There are many types of ecosystems: deserts, tropical rainforests, mangroves, swamps, coral reefs, estuaries, mountains, grasslands, and more.
Biodiversity loss is caused by human activities: habitat loss, climate change and pollution.
We have become aware of the loss of biodiversity. For example, the dramatic decline in monarch butterfly numbers is widely believed to be due to habitat loss.
Biodiversity loss extends to a large number of plants and animals, as described in Part 1 of this series. There is growing concern about these losses, which harm plants and wildlife and ultimately threaten society's dependence on the natural environment.
This concern motivates programs at the state, national and global levels to reduce biodiversity loss and reverse this process.
In a recent initiative, the California Native Plant Society reported: "Tribal and community leaders across California are coming together to promote four national heritage sites that will together create at least 700,000 new acres of native land. Four campaigns are calling for new national monuments or expansions for Moloch Luuk, the San Gabriel Mountains, Chuckwalla and now Medicine Lake Highlands. Land conservation preserves the diversity of ecosystems and helps protect native plant and animal species and their habitats. .
Citizen participation in such efforts represents an opportunity for interested individuals to contribute to biodiversity conservation.
Today's article focuses on the loss of biodiversity at the garden level and the role of individual gardeners in protecting biodiversity in gardens.
The photo gallery in this column shows the plants in my garden that are currently in flower or on display, they are representative of plants that have been selected to ensure biodiversity.
Our exploration of options for protecting biodiversity in your own backyard addresses three levels (species, genetics and ecosystem) and three causes (habitat loss, climate change and pollution) of biodiversity loss.
Habitat features place limits on wildlife habitat, so gardeners must do what they can to preserve or restore wildlife habitat.
Here are some measures that correspond to our general rule of "gardening with nature".
First, incorporate native plants to support wildlife, suggests scientist and author Doug Tallamy. His ideas and advice can be found in his books (visit your local bookstore or on Amazon) and online tutorials (found at youtube.com). Native plants, especially those native to your area, are beneficial to insects, birds, amphibians, reptiles and mammals. A good source of information about native plants in your yard is the California Native Plant Society's online plant selection tool, Calscape (calscape.org).
Another positive measure for plant breeding is the removal of invasive plants that can crowd out native plants. One resource for information on identifying invasive plants is the California Invasive Plant Council (www.cal-ipc.org).
While some gardeners like to dedicate their gardens to plants that are native to their particular environment, planting for diversity can also include non-native plants. A selection of different plant species must still provide nectar, seeds and protection for wildlife. To grow successfully and ensure biodiversity, choose plants that adapt to your soil, terrain, climate, sunlight and rainfall.
For the Monterey Bay region and California in general, the focus of this plant selection is clearly on drought-tolerant plants, a recognition of the diversity of your ecosystem. With this method, the gardener can reduce garden watering by hand watering newly installed plants and using drip irrigation when necessary.
Because plants adapt to environmental conditions in response to human-induced climate change, gardeners must be careful to select plants suitable for their particular environment. This genetic change is of course a slow process, but we are already seeing reports of plants and animals moving to new areas to create more tolerant, warmer or colder conditions.
Another important measure to ensure biodiversity in the garden is to avoid the use of artificial fertilizers and pesticides. These products may only be effective in the short term, but they end up polluting your garden and environment and are often harmful to wildlife. Composting garden and kitchen waste and returning these nutrients to the garden is both cost-effective and part of protecting biodiversity. The purpose of adding organic matter to the garden is to compost the leaves of trees and shrubs, if only to let them decompose naturally in the soil.
Expand your gardening knowledge
The California Native Plant Society's natural gardening webinars provide valuable plant-focused information resources for home gardeners committed to protecting biodiversity. Visit their website (www.cnps.org/gardening/webinars) for an impressive list of recorded webinars and information on upcoming webinars. Both recorded and live webinars are available for free.
The next live webinar, "TLC for Native Trees," will be held Dec. 7 at 5:30 p.m. "California's native trees are truly impressive: they can reach majestic heights, live for thousands of years, and require dozens of people to hug them. But how do we care for them when they're in our gardens?" Oscar Sanchez of TreeCare LA and the CNPS horticulture team, experienced California native tree experts, will provide information on tree care.
Enjoy your garden and participate in the important work to protect biodiversity.
Tom Kerwin is past president of the Friends of the UC Santa Cruz Arboretum and Monterey Bay Iris Society, past president and life member of the Monterey Bay Area Cactus and Succulent Society, and UC Lifetime Master Gardener (certified 1999-2009). Today he is a board member of the Santa Cruz Hostel Society and active with the Horticultural Society of the Pacific. To see photos of his garden, https://www.facebook.com/ongardeningcom-566511763375123/. For gardening information and an archive of On Gardening columns, visit ongardening.com for past columns or visit www.santacruzsentinel.com/ and search for "carwin" to find new columns. Email comments or questions to bagani@karwin.com.
