Tropical scrub forest is one of the biomes that make up aridland. This type of biome also consists of desert and areas of low-lying, dense underbrush. It is an area of little precipitation, plenty of continuous winds, poor drainage and medium to poor soil quality. The plants and animals of the tropical scrub forest have adapted to flourish in this harsh environment.
Tropical scrub forests, or chaparral as they are referred to in California, are found across the southern United States, along the Mediterranean coastline, in north and central Africa and within the interior of Australia. Average annual rainfall is only 2 to 9 inches, and the temperature fluctuates very little, averaging near 64 degrees Fahrenheit all year round. Virtually all tropical scrub forest is found in the same equatorial region, and temperatures fluctuate little regardless of season.
Vegetation in the tropical scrub biome has adapted to arid conditions. Plants typically have thick, waxy leaves that have developed to store moisture. Trees that grow in this biome include hardwoods such as oaks and varieties of both deciduous and evergreen trees such as olives and cedars. Flowering shrubs such as manzanita grow into dense evergreen thickets. Summers are dry, and most plants are dormant until the winter rains.
Like the vegetation of the region, the local animals have adapted to the harsh, dry conditions of the tropical scrub forest. Most mammals are small and nocturnal, able to change their body temperature rapidly and take advantage of the cool night temperatures. Other nocturnal and burrowing animals of this biome include snakes, lizards and small rodents. Many small animals have also evolved with longer legs and high agility to facilitate movement along shifting and hot soil.
Other features of the tropical scrub biome are related to precipitation and evaporation. The soil of the tropical scrub biome is porous and light, unable to retain moisture or provide drainage. Irrigation is often ineffective in the long term due to high evaporation levels. Plants grow thick and low to the ground, equipped with extensive root systems that are designed to seek and store water. Some plants have even evolved the ability to absorb the moisture of the nighttime mist.