A few weeks ago, Pam and I drove out to Wind Drift Farm in the Village of Poestenkill, New York. We returned home with 20 young laying hens – nine New Hampshire Reds, nine Bard Rocks, and two Araucanas. All except the Araucanas will begin producing brown eggs pretty soon. (Actually, they are already producing “tiny” eggs that young hens make as their physiology shifts into laying mode). Araucanas produce the same kinds of eggs as the ‘Reds and the ‘Rocks, but their shells are green. Soon our new hens will replace our Red Sex-links, who have been producing eggs for us for more than three years and are beginning to age out.
You may have noticed that in the last two paragraphs I named four different kinds of chickens, all laying hens, that live on our farm right now. On top of that, we just processed a fifth kind of chicken – the Cornish Cross broilers – a completely different kind of bird. Heavy with meat, and hot to the touch, due to their explosively high metabolism, these “meat birds” look nothing like the layers. So, you may wonder, “Why are there so many kinds of chickens?”
In fact, the five breeds at Longfield Farm are just noise around the signal. There are more than 145 kinds of chickens on farms around the world. Variety is the name of the game in sustainable agriculture. Some 244 distinct breeds of sheep, 450 cattle breeds, 217 kinds of horses, and more than 300 breeds of pigs live with us on planet Earth right now. And that doesn’t include the crosses among breeds that farmers have been making for thousands of years. So why are there so many kinds of farm animals?
To answer that question we might, as we so often do here at Longfield, seek Nature’s wisdom. That wisdom comes to us in the form of an address to the American Society of Naturalists (ASN) by Yale University ecologist, G. Evelyn Hutchinson in 1958, on the occasion of his being elected president of the ASN. His presidential address to the Society was titled, “Homage to Santa Rosalia, or why there are so many kinds of animals.” We’ll skip the connection to Santa Rosalia and go right to the second part of the title – “why there are so many kinds of animals.” Hutchinson explains that nature provides an infinite number of niches for animals to occupy. What’s a niche? Is it an animal’s habitat? No. Niches are distinct from habitats. If we think of an animal’s habitat as the place where it lives – its address – then an animal’s niche is its “occupation.” The niche includes all the things a species does and experiences within the space it occupies. Hutchinson considered the niche an “n-dimensional hyperspace,” and it gets more complicated from there, but what I’ve described here will suffice for the purposes of this essay. Importantly, some parts of the planet, such as polar regions and deserts, have few niches, so they support few species. Others – the tropics, and especially rainforests – have many. They contain hundreds, even thousands, of species of animals and plants.
Why is this important? Well, the more species, i.e., the greater the biodiversity, the more resilient the ecosystem is to disturbance. University of Minnesota Professor, David Tilman and his colleagues conducted a series of experiments at the university’s Cedar Creek Research Center, in which he planted more than 200 plots of land with varying numbers of grass species. Some of these experimental plots contained many kinds of grasses, and some contained only a few. The plots received differing amounts of fertilizer. Each plot represented a small, experimental ecosystem. As time passed, the environment varied in fairly predictable ways, from wet to dry, warm to cool. Plots with few species of grasses experienced that environmental variability more severely than those with many species. In biodiverse plots, a species or two might be lost when conditions were unfavorable for those species, but overall, the productivity of Tilman’s biodiverse experimental ecosystems remained relatively stable. In plots with few species, stress in the environment (e.g., a drought) might cause the functioning of the entire experimental ecosystem to decline, or even collapse. So, biodiversity helps maintain ecosystem stability in the face of environmental variability. That seems rather important today, as climate change is stressing many of Earth’s ecosystems.
But what does that have to do with farms and farm animals? And once again, why are there so many kinds of farm animals?
Well…really, there aren’t so many kinds of farm animals.
Although scientists estimate that there are between 3 and 30 million kinds (species) of animals on Earth, only 14 have been domesticated. What there is, however, is variety – variety within domesticated species. Among the animals, we use the terms breeds or races to describe genetically distinct variations within a species. Among plants, genetically different members of the same species are called varieties or cultivars. The numbers of varieties of plant species are staggering. For example, the native people of the Andean Mountains, domesticated the potato 7,000-10,000 years ago. They developed more than 4,000 varieties of potatoes, each adapted to a different micro-environment, from low altitude to high, from near-desert to near-wetland.
To understand why is this important, consider the following: In the 19th century, the people of Ireland grew one kind of potato, the Lumper. It grew well in the poor Irish soils where most of the people lived. In 1845, a fungus-like organism called Phytophthora infestans attacked the Irish potato causing a devastating disease called late blight. The blight killed nearly the entire potato crop for about five years, virtually extinguishing the single most important dietary staple of the Irish people. As a result, more than a million people starved. Many more left their country to begin new lives abroad. While Lumper potatoes were susceptible to the blight, nine kinds of South American potatoes, all part of the ancient Andean diet, are resistant. In other words, varietal diversification, reduces the risk of catastrophic loss of a crop and the human consequences that may follow.
The story is similar in the Animal Kingdom. Although few species have been domesticated, the variety within-species, i.e., breeds, is impressive. That variety permits farmers, ranchers, and herders to manage animals that are well-adapted to the habitats and niches within which they are managed. Take sheep for instance: Breeds like the Awasi, which were domesticated under the Mediterranean to desert conditions of Middle East. Icelandic sheep, on the other hand, do fine under boreal and Nordic landscapes. Some breeds, like the Merino, produce superb wool, while “hair sheep” breeds, like the Dorper, have a shedible fur rather than a woolen fleece, but produce excellent meat. Dual purpose breeds, like our Romneys, produce both good wool and good meat. Romneys were first bred in Romney Marsh in the UK. So, they are quite good in wet environments. They rarely get hoof rot. However, they prefer cool weather and they do not like the dog days of summer at all, especially as those days seem to be getting warmer every year. The genetic diversity that defines sheep breeds, allows one to pick breeds to raise that have the quality closest to optimal for the conditions and market-goals of one’s farm. By selectively crossing breeds, a farmer can “create” an animal best suited to one’s farm. In a few years, I may find myself crossing our Romneys with a warm-weather breed, as the Earth’s climate continues to deny comfort to breeds that prefer cool weather. So, increasing the genetic diversity of my flock will increase the sustainability of my sheep enterprise.
Last weekend, Pam and I took our grandsons to the Altamont Fair. As we moseyed through the Poultry Barn the boys ogled at the huge variety of Bantam chickens on display. Each bird seemied bred to be more outrageously flamboyant in its appearance than the chicken in the next cage. If you’re wondering what advantage all that crazy plumage confers to the chicken, well…you can stop wondering. There is no advantage. But to the youngster who bred and raised this crazy chicken, which is now maybe a contender for a blue ribbon at the fair, a million lessons have been learned – from animal husbandry, to being responsible for another living being, and even some genetics. It all leads to the thrill of that moment when the judge puts a ribbon on the cage.
So, we start and end with chickens, which is my long-winded way of telling you that we expect to be selling the eggs from our rather diverse flock of young, pastured hens, fairly soon. Perhaps more importantly, we have answered the question, ‘Why are there so many kinds of farm animals (and plants)?’ It is because biodiversity creates stability. Biodiversity allows ecosystems to be resilient in variable environments. Nature defines biodiversity in wild ecosystems in terms of both species richness and genetic variability, while agriculture has focused more on the genetics within a few domesticated species. In agriculture, genetic diversity provides farmers with options about what to grow, and security against crop failure. That translates to stability of the farm ecosystem. Biodiversity opens markets, and thereby enhances the sustainability of one’s enterprise. And sometimes it simply provides a next-generation farmer with a blue-ribbon bantam chicken, bred specifically for its flamboyant plumage.