SciSun: Frankly, my Deer   Leave a comment

Throughout much of North America, particularly the Eastern, Midwest, and Southern US, deer are running wild. Not like the average White-tail deer isn’t normally wild; but for the past few decades, this species is being found in more numbers, and more places, than anyone has seen before; and the effect these deer have on natural ecosystems, and even on man-made environments, have some scientists worried. Yet at the same time in California and other Western States, there seem to be fewer deer every year; which also is an unusual situation that has scientists asking “What’s with the Deer?” (And maybe a few scientists who say “Oh Deer.” But that’s too obvious).

First we have to understand the White-Tail deer (Odocoileus virginianus) is the most commonly-seen deer in North America, ranging from the Atlantic coast westward. However they are uncommon in the southwestern deserts, and not considered a native of the far West Coast (but they’ll move if they get a good job offer). The deer usually found in these western environments is the Black-tail deer (Odocoileus hemionus), a sub-species of the Mule deer (again, O. hemionus), which is a close relative of the White-tail. So while a-deer-is-just-a-deer isn’t absolutely correct, it is true that all deer are herbivores, living at forest edges and scrubby grasslands, and are important in keeping plants from growing out of control; and as prey for carnivores. While living in different locations and in unique ecosystems, all deer live and behave very similarly to each other.

We have two different types of deer, one is doing very well and the other not-so-much. Puzzle solved. But it’s not that easy, because the different species of deer are living with the same environmental challenges that are affecting their populations: Changes in food sources due to farming and suburban growth; drastic transformation of landscapes and water sources like re-routing streams and building dams; loss of predators that in a healthy environment keeps deer from over-population; and human plans and actions that were intended to help deer, and the environment, but probably made things worse.

No one knows how many deer there were hundreds or thousands of years ago, but it’s estimated that before North America was ‘discovered’ (although there were already lots of people living here who didn’t even realize the land hadn’t yet been found. Who knew?), there were about 10 to 15 deer per square mile. After the lands were settled, forests cleared and hunting became widespread, deer population (and the populations of other species, too) sharply dropped to the point some people were concerned there weren’t enough deer. So beginning in the 20th century deer were actually transported thousands of miles to re-establish populations that had been over-hunted and had virtually disappeared. These deer were placed in protected areas and, as there weren’t many large predators left in those areas, the deer flourished. Today some areas of North America have 30 to 35, or more, deer per square mile.

'Welcome to Deer-a-Thon 2013!  Come for the snacks; stay for the social networking.'

‘Welcome to Deer-a-Thon 2013! Come for the snacks; stay for the social networking.’

And these deer are eating everything they can, from shrubs to young trees to backyard gardens to farm crops to decorative plants. About the only thing they don’t eat are large trees, that they can’t reach; and grass, which they can’t digest. So these deer-fields are left with no bushy-ground cover wildlife need for homes, or protection, or food; and there are very few young plants left standing, so in time (some scientists estimate just a few years), there won’t be enough young trees left to take the place of old trees that die. And as the Zen-master said, “Without the Tree, where is the Forest?”

This may help explain the overpopulation of White-tails, but what about their Western cousin, the Black-tail? Unfortunately, this is a much harder question to answer. Although much of the large predator population has severely declined in the West, just as throughout most of North America, the number of Coyote (Canis latrans) has grown. Normally a coyote can’t or won’t attack an adult deer (coyotes hunt alone or in small groups, not organized packs like wolves, historically the main predator of deer); but coyotes can easily catch young and baby deer. And according to field research being conducted in California, coyotes are eating a lot of baby deer, as many as three of every four. Still, baby deer are only born during a few weeks in the Spring, so we can’t blame the scraggly coyote for the declining deer population. The availability of water, always a scarce resource in the West, could be a concern as more and more water sources are diverted and held for human needs over the needs of wildlife and wild lands. Another challenge seems to be the number and spread of non-native plants throughout the West, plants native deer can’t eat. While the forests and fields might look green and lush, many of the plants were imported hundreds of years ago by people who thought they were doing good, only now we know these species are destroying our native ecosystems.

The quantity of deer that live in one area or another probably isn’t something you think about often (or ever!) and likely makes little difference in your everyday life. But we know there are too many deer in some places, and not enough in others, and that’s a result of poor choices and actions in the past that are affecting entire environments, today. Often the space, water and resource needs of man can just as easily be balanced with the needs of wildlife and healthy ecosystems. When it’s a question of environmental balance, remember that Frankly, we should all give a Dam.

http://ucanr.edu/sites/oak_range/Oak_Articles_On_Line/Oak_Woodland_Wildlife/California_Oaks_and_Deer/

http://www.lpzoo.org/conservation-science/science-centers/urban-wildlife-institute

^^^

Michonne Says: That’s a lot of deer. Sometimes I see them eating berry bushes and that’s just greedy. Everyone knows you only eat the berries, not the bushes. It’s like they have no manners. So I’m going to eat all the berries I can before the deer find them.

Posted March 24, 2013 by ECOVIA eco-adventure® in SciSun

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