Appendices & Glossary - Botanical Research Institute of Texas

1274 APPENDIX NINETEEN/NATIVE PLANTS IMPORTANT TO WILDLIFE IN EAST TEXAS
Although each species of wildlife has specific life requisite requirements (habitat), these resources
vary seasonally and locally, especially for those species that are distributed over a large area and are
generalists rather than specialists in their requirements. Few wildlife species have been studied sufficiently
to provide information that goes beyond the local area where the studies were conducted;
therefore, so to generalize about their life requisites throughout their range of distribution is difficult.
Also, the situation becomes extremely complex when multiple species are involved. The only specific
assessment of plant values to wildlife that has been accomplished is the ranking of food use by species
or wildlife groups. Therefore, in the following lists if an asterisk “*” is associated with the common
name of a plant genus or species, it signifies an especially important food source for wildlife (b = deer
browse (including fruits and herbage), f = fruit, h = hummingbird nectar, n = nectar source for bees and
butterflies, r = rhizomes, s = seeds, t = tubers, w = whole plants as forage). In addition, an “x” designates a
plant somewhat to mostly resistant or unpalatable to deer, but beneficial to other wildlife. However,
few native plants are toxic or distasteful enough that deer will avoid them completely. Some plants are
avoided at certain growth stages or seasons. During stress periods, and where deer numbers are high,
even plants normally avoided may be eaten. Therefore, an “x” does not guarantee that the plant will
not be damaged by deer under certain conditions.
If readers are interested in more information about these plants, they should refer to the individual
species accounts via the index, consult the references, or access the Texas Plant Information Database
(TPID) Web site (http://tpid.tpwd.state.tx.us/) where extensive data can be obtained.
WOODY PLANTS
Woody plants characterize the natural vegetation of the East Texas ecological region. The basic groups
are trees, shrubs, and vines, each of which includes deciduous, evergreen, upland, and bottomland species.
There is much variety within these vegetation associations (vegetation types). These include upland
forests, bottomland forests, pine forests, deciduous forests, mixed forests (pines and hardwoods),
pine and hardwood savannahs, riverine (riparian) zones, swamps, bayous, sloughs, and oxbow lakes.
TREES
Trees provide three distinct layers, strata, or galleries in the canopy (low, medium, and high). Some animals
spend the majority of their lives in a single layer, while others may range over two or more layers.
Unlike other types of vegetation, mature long-lived hardwood trees develop natural cavities, hollows,
and loose bark that provide shelter and nest and den sites for many kinds of animals. Tree trunks are
used by specialized birds such as woodpeckers, nuthatches, and the Brown Creeper (Certhia
americana). Woodpeckers are especially important since their excavated cavities are also used by
many other animals. Trees also provide attachment for climbing vines that add to the variety of
canopy layers. Evergreen trees are important for escape cover and winter shelter.
Dead trees and large limbs (snags) should not be removed unless they pose a potential hazard. They
provide important perches, and woodpeckers use the resonant qualities of deadwood for drumming—a
communication technique used to indicate territorial boundaries and to attract mates. Downed decaying
trees provide shelter and reproductive sites for a wide variety of invertebrates and vertebrates.
Their eventual decay returns valuable nutrients to the soil.
Diversity of tree species produces a variety of insects and fruits available throughout the year. Oaks
should include species of both the white oak and red oak groups. White oaks bear acorns that develop
and mature at the end of one growing season, whereas acorns of red oaks mature at the end of 2 growing
seasons. White oak acorns are “perishable” since they have “rapid-response” generation, i.e., ripen,
fall, and sprout in the autumn. In contrast, red oak acorns are “storable” since they have “delayed-response”
germination, i.e., ripen and fall in autumn, but do not sprout until spring. Some oaks bear large
crops annually; but, most acorn crops are cyclic, heavy crops being produced about 1–2, 1–5, 2–3, 2–4,
3–4, 3–5, 4–6, and 4–10 years depending upon the species. Thus, a variety of species within and between
the two oak groups insures some availability of acorns.