Sunday, September 27, 2020

Why Natives Matter: Birds

Last week I wrote about how using Georgia’s native plants in our landscaping supports our native insects better than using non-native plants. In this post, I’d like to talk about why using native plants matters to our native birds.

The first thing to understand is what birds eat, both as an adult and as a nestling. The 3 main categories for adult birds are frugivores (fruits), granivores (seeds), and insectivores (bugs) like the hooded warbler at left, plus omnivores (a bit of everything) and nectivores (nectar-eating birds such as hummingbirds). The major food for nestlings is far and away insects (96% of birds eat insects when in the nest).

How do native plants help those different types of birds better than non-native plants? 

Insectivores – This category, which represents the vast majority of birds when you factor nestlings into the equation, benefits from the relationship of insects to native plants (what I talked about last week). Herbivorous insects (those who eat leaves and other parts of plants) have evolved with their plant partners to the point where some won’t eat any other plant. If you want insects to feed your birds and their babies, you should plant a variety of native plants and especially the keystone plants (a termed coined by Doug Tallamy to represent the plants that provide the most significant support to insects, see page 139 of his book, Nature’s Best Hope).

Photo by Romin Dawson

Granivores – This category of birds eats seeds primarily and includes one species of bird, the American goldfinch, who even feeds seeds to its young (in case you wondered who was in the 4% of nestlings not eating insects). While a lot of people do supplement these birds with purchased seeds, supporting them with plants is beneficial (especially when you run out of seed during a pandemic and don’t want to go to the store!).

A goldfinch eats thistle seeds (as seen through the deck slats)

– This category of bird consumes a lot of fleshy fruits but will occasionally eat insects or seeds depending on availability (still not enough to be considered an omnivore). These birds greatly benefited from the push to plant berry plants some years ago, sometimes to the detriment of the environment as well-meaning folks planted non-native plants that became invasive in some areas (think privet, autumn olive, mahonia, and nandina). Scientific analysis shows us that native fruiting plants provide more nutritious fruits than the non-native plants. This article from Audubon highlights several studies, including this one.

Left to right: Spicebush fruits, Beautyberry fruits, and American holly fruits are all very popular

So if you want to support birds as much as possible, plan to use more native plants. Check out my earlier blogs for tips:

Natural Bird Food

This is the final installment in my 3-part series on Why Natives Matter. If you missed the others, you can read the first one here: Sense of Place and the second one is here: Bees, Butterflies, and Bugs.

Sunday, September 20, 2020

Why Natives Matter: Bees, Butterflies, and Bugs

Last week I wrote about how using Georgia’s native plants in our landscaping helps to give our gardens and landscapes a sense of place. In this post, I’d like to briefly cover why using native plants matters to our native insects. Why briefly? Well, because people have written whole books on this topic (see Doug Tallamy’s first and third books to learn more), and I am not the expert.

As you may know, plants and insects have evolved over millions of years; what you may not realize is that they did it together. A series of mutually beneficial changes took place over millions of years until we have the plants and insects we have today. Some of them are linked together in ways that affect their very survival; the life cycle of the Monarch butterfly and its relationship to milkweed is more well-known than ever and a great way to understand the host plant relationship. 

The cloudless sulphur butterfly (shown at left) is abundant today thanks to natives like partridge pea (Chamaecrista fasciculata).

Occasionally, someone will argue that having new plants introduced (e.g., brought here from somewhere else) increases the biodiversity and proposes that that must be an improvement. However, given the complex evolutionary relationship between insects and plants, there are 3 potential problems with introducing new plants:

1. They do not immediately contribute to the food web that supports native insects; often offering only pollen and/or nectar. Native insects cannot complete their life cycle on them (i.e., lay eggs on their and have their young eat some of the foliage). There are some limited exceptions, of course, when non-native plants are closely related to native plants such as the ability of parsley and fennel to support Eastern black swallowtail butterfly caterpillars. 

2. They displace native plants that do contribute to the food web, thereby reducing the amount of insects that can be supported in the same square footage. 

3. They become invasive sometimes, displacing more native plants as they invade natural areas, and thus further reducing the amount of insects in the area.

Zebra swallowtail will only lay eggs on native pawpaw

Native plants support insects and pollinators far better than non-native plants – that is proven in study after study after study. From bees, to butterflies, to many of the other bug categories (flies, wasps, beetles) that depend on plants, native plants give so much more to the ecosystem than pretty flowers or even pollen and nectar. They aren’t just there, they contribute.

In the case of closely linked relationships, if a plant population were to decline too much, specialist pollinators populations would decline as well, resulting in a mutually destructive downward spiral towards extinction for both. Even for generalist plant-pollinator relationships, a decline in insects yields a decline in pollination resulting in fewer viable fruits/seeds and a decline in the diversity of plants.

If contributing to the insect population--bees, butterflies, and other bugs--matters to you, increasing the percentage (and variety) of native plants in your landscapes makes a difference.

This has been installment two in my series on Why Natives Matter. If you missed the first one, you can read it here: Sense of Place.

Rose-mallow bee is a specialist on Hibiscus

Sunday, September 13, 2020

Why Natives Matter: A Sense of Place

In the weeks leading up a virtual panel discussion that GNPS is sponsoring (and I’m moderating so I’m definitely thinking about it a lot), I’ve wanted to put in writing some of my thoughts on this topic. While there are several aspects to why native plants matter [in conserved areas and in our gardens]—and I expect the panel to touch on those: pollinators, birds, etc.—there is one aspect that doesn’t get the attention it deserves. 

It is the concept that native plants give ecoregions a sense of place.

Ecoregions are unique physiological areas and, at the state level, Georgia has five of them: Cumberland Plateau, Blue Ridge, Ridge and Valley, Piedmont, and Coastal Plain (the Coastal Plain can be further divided into the upper Southeastern Plains and the lower Southern Coastal Plain/Maritime). Each of these regions is home to hundreds of native plant species, from towering native oaks (Quercus) to small single-leaf native orchids like the crane-fly orchid (Tipularia discolor). While some plants span multiple ecoregions, others occur in such unique environments that they grow only in one.

Mountain laurel (Kalmia latifolia)

How many of us love to travel to the North Georgia mountains in the spring to see trilliums, mountain laurel, and rhododendron? Who doesn’t smile when they arrive in South Georgia to see acres of saw palmetto dotted with towering cabbage palms or an expanse of wiregrass and longleaf pines? How about the waving sea oats and the beach morning glories on the dunes at the beach?

Saw palmetto in South Georgia with pines

Beach morning glory (Ipomoea imperati)

In landscaped areas, we’ve lost the concept of Georgia plants. As we walk around our neighborhoods, drive along roads with landscaped median strips, and pass through shopping and business areas, what plants are there? Knock-out roses, non-native juniper shrubs, Japanese azaleas, Loropetalum, waxleaf privet, crape myrtles, and Cryptomeria. Encase those in a wrapper of non-native annuals, elephant ears, purple fountain grass, and dyed mulch and you have a landscape that you can see repeated from Georgia to New Jersey, and—surprisingly—from the east coast to the west. A canned list of non-native shrubs, trees, and seasonal bloom annuals/perennials seems to be passed from one designer to another, fueled by big box stores and nurseries that churn out endless supplies of these plants.

Why not appreciate the natural beauty of our regions and use our native plants as the primary landscape plants? Instead of knock-out roses in sunny spots, how about native plants like: St. John’s wort shrubs (Hypericum), Fothergilla, dwarf wax myrtle, hollies, summersweet (Clethra), viburnums, beautyberry (Callicarpa americana), blueberries, Spiraea, buckeyes (Aesculus), shrub dogwoods (Cornus), and more. Might we have to change the way we design those spaces to fit some of these? Perhaps, but don’t let a challenge stop us!

I cringe when I see beautiful mountain homes landscaped with non-native plants like butterfly bush, rose of Sharon, and crape myrtle. They could be decorating their landscapes with gorgeous native rhododendrons, azaleas, and mountain laurel. Why take a beautiful area and make it look like everywhere else?

Virginia sweetspire (Itea virginica)

I love finding landscapes where oakleaf hydrangea (Hydrangea quercifolia), Virginia sweetspire (Itea virginica), and Fothergilla have been used in the design. How refreshing to see these “unusual” choices show up. I usually always pull over and admire them. Perennial choices like purple coneflowers (Echinacea), black-eyed Susans (Rudbeckia), and pink muhly grass (Muhlenbergia) get the most use when it comes to natives, from what I can see. The need for continuous-flowering plants is what often drives choices to non-natives, but thoughtful selection could solve that. How about a 50-50 mix of native and non-native to get us started? Of course, we should pick regionally appropriate choices as much as possible.

When you're thinking about what to plant in your garden, think about choosing the plants that make Georgia and the Southeast unique: native plants. They'll beautify your yard and contribute back to the bigger ecosystem around you while also showcasing more of the natural beauty of Georgia.

Designed sweep of Christmas ferns at a garden

Sunday, September 6, 2020

A Tad Adventurous

Most often we go through life without witnessing the life process of the many creatures that share our world. Maybe the closest we get is to watch a butterfly lay an egg, the egg turn into a caterpillar, and then that caterpillar transform into a butterfly. This year, I was delighted to watch frog eggs go through their transformation from blob to frog.

After an unusually rainy string of days in July, we discovered frog eggs in a container on the driveway. I had actually been hoping this would happen because I’d seen gray tree frogs checking out the container at night. Shortly after that, the kiddie pool in the backyard—this time filled with water for the grandson—was the recipient of quite a few deposits. Gray tree frogs were caught in the act several days later when the chorus of mating calls was so loud that I felt compelled to see what was happening.

Gray tree frogs making it happen
Leaf being nibbled away

At some point I combined the two populations into a single large container where we could better watch them (and regain use of the kiddie pool for its intended purpose). There must have been about 200 of them! For food, we put dead leaves in the container. They seemed particularly fond of bigleaf magnolia (Magnolia macrophylla) leaves; after several days, there would be nothing left but the lacy veins. Later we bought some tadpole food; I could not tell if they preferred it.

Occasionally we would use the kiddie pool to remove them and clean out the container. We were careful to set aside fresh water a day in advance so that it could de-chlorinate (one could also use rain water). A horrible setback occurred when raccoons discovered the unprotected container (no top) and ate about 95% of them. Talk about your midnight massacre (or buffet). Fortunately, we were able to raise the remaining ones (about 20 tadpoles).

The progression of growth was fun to watch: first they got their back legs, which grew from tiny sprouts to noticeably jointed frog legs; days later, they got their front legs. Once they get their front legs, they need something to climb on. I thought that the sides of the container would be enough for them, but that probably takes more energy. They can drown if they can’t get out. We put several big sticks in there; you could also use rocks. Leaves might float for a few days but then unexpectedly sink so don’t rely on them for this purpose.

A nice big stick protruding out of the water helped

Those two bumps on the frog look like legs waiting to pop out

It was surprising how much time elapsed between the back legs and the appearance of the front legs, perhaps indicative of needing more time to support internal changes going on as well. Once they got their front legs, the process moved quickly. Most were released within two days, usually first thing in the morning. You know they’re ready when you realize their tail is stubby – apparently they eat it as the last step (for energy?).

Glamour shots (not all the same frog)

They will tolerate a little handling just before releasing, but they quickly get the hang of leaping faster and further. It was a fun adventure and another step in learning about nature for my grandson.

A quick check before this one took off
My friend gave him a toy growth set so we compared