Why Grow Native

Maybe you have noticed a decline in our pollinator population with your own eyes but let me assure you that what you have noticed can be backed by research. The decline of our insect population had accelerated during the 1950s and 1960s and has continued to decline at an alarming rate during the past 40 years. In fact, according to a study by Science.org, invertebrates (mostly insects) have declined by 45% in the last 40 years. Scientists have also concluded that 2 out of 5 inveterate pollinators are on the verge of extinction. Unfortunately, insects are not the only pollinators in decline.  According to a study by Science.org, the number of birds has declined by 2.9 billion since 1970. Because 90% of flowering plants require some type of animal interaction for pollination, researchers have deemed the declines a pollination crisis.

There are several factors that have contributed to this alarming decline in our pollinator population. From spreading diseases brought in by foreign insects, pesticide use, and loss of habitat, our native pollinators are slowly being erased. 

Large-scale farmers bring in foreign insects to help with pollination, thereby spreading foreign diseases that our pollinators are not used to dealing with. Hopefully, with some education, our large-scale farmers can learn about using our native pollinators to help with their pollination needs. With Organic foods being a growing trend, and as we learn about how devastating pesticides are to our pollinators, we can only hope that using toxins is a dying trend. Many of us that care about our local pollinators have likely already taken steps to eliminate pesticide use on our own properties. But according to Douglas Tallamy, Etymologist for the University of Delaware, author of 104 research publications and 7 books, teacher, and environmental advocate, stresses that there is another big cause for their decline: "One potential cause (...) is the global spread of non-native plants as invasive species, agroforestry products, and ornamental plants." This not only includes lawns and exotic landscaping, but also large-scale industrial farming and the use of pesticides (which are used to help aid these plants to survive in areas they have not adapted to living in). To counteract this devastation to our native pollinator's habitats, Tallamy strongly encourages people to grow native and to grow natural. 

The insects that seem to be the most dramatically affected by the decimation of their native ecosystems are our butterflies. Over the last 20 years, Monarch populations have declined by more than 80% (though they have made a 35% comeback in the year 2022). In the Western United States, more than 450 butterfly species have declined at an average rate of 1.6% a year and some may completely disappear from parts of their ranges in the coming decades, says researcher and insect ecologist at the University of Nevada, Matthew Forister.

Loss of habitat effects butterflies so greatly because many are very particular about where they lay their eggs. Some butterflies have a comparable selection to choose from when it comes time to lay their eggs, but many others can only lay their eggs on plants of specific species. In fact, 69% of caterpillar species can only survive off of one specific plant species. For example, the Monarch will only lay their eggs on Milkweed and the California Sister Butterfly will only lay their eggs on our native oak trees (they overwinter in the oak trees as well).  For butterflies, a native habitat is crucial for their survival. 

Where our butterflies are some of our most beautiful pollinators, our bees are our most efficient pollinators. Now, the European Honeybee seems to get a lot of credit for pollination, but they do not hold a candle to our thousands of other native bees. Unfortunately, Honeybees are actually an invasive species that absorbs much of our native bee's food sources. Our native bees such as Mason and Bumblebees are much better at pollination and are also the bees that we must focus on in order to "Save Our Bees." Mason bees are 120 times more effective at pollinating than the Honeybee. They have a 95% pollination rate whereas Honeybees have a 5% pollination rate. Another bee better at pollinating is the Bumblebee. Bumblebees are faster pollinators and visit more flowers per minute than the honeybee and they can work in temperatures below 50 degrees Fahrenheit. Because of this, they are out pollinating earlier in the spring and later in the Fall. They are also more willing to pollinate during a windy or rainy day.  Unfortunately, our bee's skills are not saving them from a rapid decline in numbers. In fact, 40% of our bee species are declining at rates that make them vulnerable to extinction.  More than 25% of the bumble bees indigenous to the United States and Canada are at risk of extinction and there are four species of Bumblebees that that have declined 96% in the last 20 years. There are three species that are already extinct.

Native plants are important for our bees because they have coevolved with our efficient pollinators. Experts agree that native plants offer the most benefits in terms of nectar, pollen, seeds, shelter, building material, and nesting sites. Research has shown that our native bees prefer pollen from native plants to rear their young. In fact, some bees are so particular about their nectar source that they can be classified as Specialists, which means that they have adapted a symbiotic relationship with one specific species of plant. 35% of our native bees are Specialists.  Without this special plant that they have adapted to depending on, the bee dies off. One such species in the Pacific Northwest is a Sweat Bee by the name of Dufourea calichorti.  This bee is a Specialist for the Mariposa Lily (Calochortus). 

When we think of pollinators, most of us think of our butterflies and bees but our native birds also have an important role in sustaining a thriving ecosystem. In the Pacific Northwest, Hummingbirds and the Bullock's Oriole are two of our bird pollinators. Like our butterflies and bees, hummingbirds and Orioles also drink nectar and therefore spread pollen amongst plants.

In addition to spreading pollen, our native birds help our ecosystem by spreading seeds. The Blue Jay and the American Robin are examples of two birds that spread seeds. The Blue Jay will take and bury seeds up to 2.5 miles from their original location.  The American Robin will eat the fruit and because they are unable to digest the seeds, they will spread the seeds through their droppings. Many plants such as our native Blackberry and native Raspberry have adapted to birds eating their fruit and now require a type of digestion in order to germinate.

Like our butterflies and bees, birds also favor native plants over introduced species. When the birds are looking for food for themselves and their babies, they foraged on native plants 86% of the time. This is where they will find the caterpillars on their host plants. This is also where they will find the seeds, nectar, and insects that they are accustomed to finding on their favorite native species.

Growing native means less water use and less work. Because the plants are from the region, they have adapted to the amounts of water that naturally occurs in the area. If planted in their correct environment, once established, the plants should thrive on their own (with occasional waterings during times of extreme drought).

Not only have native plants adapted to the water they regularly receive, but they are adapted to the environment in general. They have adapted to the soil- whether acidic, neutral, alkaline, sandy, or clay. They know how to survive. They are used to the nutrients available and the microorganisms that surround them. They are used to the pests in the area- aphids, caterpillars, beetles and bees will all take in nutrients from our native plants, but they have learned to survive with them or have created defense mechanisms to keep them away. 

Our native plants have also adapted to the diseases that have occurred in our area for thousands of years. This does not mean they will not get the disease, but according to the California Native Plant Society, they are more resilient when infected. These natural adaptations mean less pesticide use and less time trying to save them.  Introduced plants need more upkeep when it comes to saving them from local pests and diseases. They have not adapted to our environment but have adapted to the environment they came from. Unfortunately, as we introduce new plant species into our environments, we also introduce new pests and diseases that our natives are not used to dealing with. For so many reasons, it's just best to grow native.

You can be part of the solution to saving our local insect populations by creating an environment our pollinators can thrive in.

In addition to turning off all lights at night and growing plants without the use toxic pesticides, you can help to restore our pollinators local habitats. Research has shown that native wildlife prefers native plants over exotic ones. Let us provide our native pollinators with the food and homes that help them to survive. Because about 75% of our own food is dependent on pollinators, our own survival depends on it. Sometimes saving the world feels impossible but if you can do your small part of replacing your pretty but useless exotics and mostly useless lawn with native plants, you can take comfort in knowing that you are contributing to a natural coexistence with our planet.

      If we humans are capable of turning hundreds of millions of acres of rainforest into

      depleted grasslands, and extirpating millions of buffalo from the plains, and billions of

      passenger pigeons from the skies and cod from the North Atlantic, we are also

      capable of returning natives to our gardens.

      Douglas W. Tallamy, Bringing Nature Home: How You Can Sustain Wildlife with

      Native Plants