Variety is the Spice of Life

And that Goes for Plants Too!

Habitat Enhancing Land Management (HELM)

“If we pollute the air, water and soil that keep us alive and well, and destroy the biodiversity that allows natural systems to function, no amount of money will save us.” —David Suzuki

Christine Middleton

There’s an old proverb, “Variety is the spice of life.” And what does that have to do with land stewardship? A lot! Healthy resilient ecosystems are composed of a diversity of interrelated species. Biodiversity in its broadest sense refers to the sum of all life on earth, from the smallest bacterium to the largest mammal. And it’s not just about the number of individual lifeforms, but also the complex interactions among them that keep ecosystems healthy.

All of Hays County except its eastern edge sits within the Edwards Plateau Ecoregion. As the map illustrates, the Edwards Plateau (#7) is surrounded by six other distinct ecoregions. The Edwards Plateau is one of the most biologically diverse regions in the United States.

In fact, biologist and conservationist E.O. Wilson, called the “father of biodiversity,” ranked the Edwards Plateau #22 in the world in terms of ecological diversity. And why does that matter? Wilson put it this way: “If we start cutting down, even in the most selfish of human terms, we will suffer because we are stripping away that part of the environment that gives us stability.”

In an interview with Reuters just before the 2021 United Nations climate talks in Scotland, Wilson saw preventing catastrophic climate change and saving biodiversity as two initiatives that must happen together: “This is the most communal endeavor with a clear definable goal that humanity has ever had, and we need…cooperation and ethical harmony and planning in order to make it work.”

We Texans are part of that “communal endeavor.” And we are certainly capable of “cooperation and ethical harmony and planning” to preserve the land we love.

Here at home, long-time Hill County Chapter Master Naturalist Jim Stanley defines biodiversity as having “… variety, in terms of both numbers of plant and animal species and sizes and ages of the longer lived species.” A sustainable ecosystem, Jim goes on to suggest, is one where “…there is a balance of the numbers of each species so that consumers only consume as much as the land can produce over the long term.”

Unfortunately, much of the diversity present in Hays County before European settlers arrived has been lost—first to poor ranching practices and the “war on cedar” and more recently to exploding deer populations and rampant development.

There are lots of reasons diverse ecosystems are preferable. One is the fact that diverse ecosystems are more likely to remain stable no matter what hardballs nature throws their way. In Central Texas, one of those “hardballs” can be a year like the current one without much rain. That might be followed by a year when the rain comes far too often. So consider this highly simplified example. The “green species” in the diagram below represent plants that survive in exceptionally dry periods but can’t handle consistently wet ones. The “blue species” represent those that thrive during exceptionally wet periods but tend to disappear during prolonged droughts.

Communities with only blue or only green species fluctuate when hit with extreme climate variability. Contrast that with a more balanced, naturally “biodiverse” community containing both. Under those conditions the decrease in one species is compensated for by an increase in the other. So instead of devastation, we see green healthy land.

Biomass (natural vegetation), with its ability to prevent erosion, is just one good reason for encouraging diversity on your property. There are lots more. A diversity of plants build and enrich soil in a variety of ways. For example, native plants need nitrogen as much as those in your garden. With the help of a soil bacterium called rhizobium, plants pull nitrogen from the air and store it in their roots. When the plants die, that nitrogen is released into the soil and made available to other plants requiring nitrogen.

Natives like Scarlet Pea (Indigofera miniata) and Texas Kidneywood (Eysenhardtia texana) are members of the Pea (Fabaceae) family; like their domesticated relatives, peas and beans, they are good at fixing nitrogen.

Both Scarlet Pea and Texas Kidneywood are also larval hosts for Southern Dogface butterfly caterpillars. And the nectar within their flowers supports a host of adult butterfly species and other pollinators.

Southern Dogface on blue mist flower
Photo by Betsy Cross

Pollinators and angiosperms (i.e., flowering plants) have relationships that have evolved over 100 million years. Over time, many pollinators became specialists who only fed or reproduced on particular plants or plant families.

If a plant in that family is not present, that pollinator too is absent. The most widely known example is the Monarch butterfly, whose existence is threatened by the elimination of milkweed along its migration routes.

Monarch caterpillar on antelope horns milkweed
Photo by Betsy Cross

On their fall migration through Texas, monarchs do not reproduce. So they don’t need milkweed, but they do need fall blooming nectar plants, such as Roosevelt Weed (Baccharis neglecta) and Frostweed (Verbesina virginica).

Frostweed is highly utilized by Monarchs during fall migration.
Photo by Betsy Cross

And it is not just monarchs. As we turn our diversified ecosystems into landscapes dominated by non-native species—whether crops or lawn turf—we are seeing dramatic declines in a lot of our pollinator species.

Insects are not the only wildlife needing a diversity of plant species to support them throughout all of their life stages and in different seasons of the year. For example, resident birds nibbling at our feeders sustain their nestlings on high protein insects, primarily caterpillars. And many species shift their diets over the course of the seasons and depend on diversity to survive. Squirrels are famous for stashing acorns. But other mammals, including deer and raccoons, also depend on acorns to see them through a hard winter. And then there are the winter migrants, including robins and cedar waxwings, who visit us to feast on the berries they find on Hill Country natives like Ashe Juniper (Juniperus ashei), Possumhaw (Ilex decidua), and Yaupon Holly (Ilex vomitoria).

Cedar Waxwing on possumhaw holly
Photo by Betsy Cross

Besides food, diverse vegetation offers shelter for everything from insects to mammals. Unspoiled nature provides places for butterflies to hide at night and for moths to shelter during the day. Places for creatures of all sorts to find relief from the heat or cold. Places where creatures can build nests to raise offspring. A healthy ecosystem includes a diversity of forms: trees, shrubs, evergreens and ground cover as well as leaf litter, brush piles, rock piles and fallen logs. For all of nature, structural diversity is important.

For long-lived perennial plants, diversity also implies a range of plant ages. Age diversity means that, as mature trees and shrubs age and die, there are younger ones to replace them. But unfortunately, browsing deer like tender young foliage, and with too many deer and no predators to keep them on the move, deer will love young saplings to death. One more reason now for us to keep or replace as much biodiversity as we can!

There are also some self-interested human reasons for diversity. Diverse landscapes are inherently more aesthetically pleasing. The dream of a beautiful Texas, a vast authentic Texas, is still alive in most of us. But as large ranches are broken up into small acreage homesteads, the grasses and forest ripped out for urban “development,” the dream dies. Maintaining diversity is very important to the health of Hays County ecosystems. Encouraging a diversity of native plants on your big or little piece of the Texas ecosystem is one way you can contribute to sustaining the health and beauty of our landscapes. Once again, diversity pioneer E.O. Wilson challenges us to cooperate to save the natural world we cherish:

“It will be one of humanity’s proudest achievements. If we fail to do it, and a large portion of the biological diversity of the world is allowed to be exterminated, for all of the generations to come that carelessness will be regarded as one of humanity’s greatest failures.”

If you would like the HELM team to visit your Hays County property and provide insights into how you might enhance the diversity of your property as well as help with other land stewardship concerns, go to https://beautifulhayscounty.org/helm/ and fill out our request form.

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Fall Migration