"It has a compound effect on a multitude of species and organisms and habitat types because of the way that it's chained and linked together," said Jeff Bonner, a wildlife biologist with the Texas Parks and Wildlife Department.
Since January, Texas has received only about 6 inches of rain, compared with a norm of about 13 inches, making it the most severe one-year drought on record. Last week, the U.S. Climate Prediction Center said the La Nina weather pattern blamed for the lack of rain might be back soon, and if that happens, the dry spell would almost certainly extend into 2012.
The extreme dry conditions have been made worse by week after week of triple-digit temperatures that have caused reservoirs to evaporate, crops to wither, and animals and fish to die.
Already, some rivers and lakes are at lows not seen since the 1950s - the decade when Texas suffered its worst drought in recorded history. And in some cases, bodies of water are at their lowest points ever.
Of the state's 3,700 streams, 15 major rivers, and several reservoirs are effectively empty, and more than half of the streams and rivers are at below-normal flow.
The drought will most immediately cause fish to die, and such kills have already happened in parts of the state. In West Texas, O.C. Fisher Lake has been so depleted that fish have died from a lack of oxygen, and bacteria have turned the remaining water red.
Without water, animals struggle with thirst. Few plants grow.
Without plants, there are fewer insects. No insects result in low seed production. The animals that rely on seeds and plants for nutrition - from birds to deer and antelope - have low reproduction. Predators that rely on those animals as a food source remain hungry as well, and they reproduce less.
"So there's a domino effect that goes out in however many more branches than you can actually ever keep count of," Bonner said.
The long-term effect from the drought will cross state lines and country borders because Texas is so large and its ecosystems diverse. For example, birds that migrate south in the winter will find little food and water this year in Texas, so they will have to fly even farther south and expend more energy. As a result, they could reproduce less.
"Now, what happens?" Bonner said. "Continentally speaking, this big of an area not getting enough water can impact places far and wide."
Officials say the effect on some species could last for years after the drought officially ends.