A shrubland biome is an ecosystem characterized by vegetation dominated by shrubs, though grasses and other short plants are also present. Scientists use a climate graph, or climatograph, to visualize the relationship between temperature and precipitation in a given area. This graph provides a clear, year-long summary of the climate conditions that shape these ecosystems.
Reading a Shrubland Climate Graph
A climate graph is a dual-axis chart that presents a location’s average monthly temperature and precipitation. The horizontal x-axis displays the twelve months of the year. The primary vertical y-axis measures precipitation, which is represented by bars, while the secondary y-axis on the right measures temperature, shown as a continuous line.
For a shrubland, the temperature line forms a distinct bell curve. It shows temperatures rising through the spring, peaking in the summer months, and then decreasing through autumn into winter. The highest point of the line graph corresponds to the hottest and driest period of the year.
In contrast, the precipitation bars display an inverted pattern, creating a “U” shape. The bars are lowest during the summer, indicating a period of drought that coincides with the highest temperatures. Conversely, the bars are highest during the cooler winter months, showing a wet season. This inverse relationship is the defining feature of a shrubland climatograph: when the temperature line is high, the precipitation bars are low.
Climate Characteristics and Ecosystem Impact
The climate pattern revealed by the graph is one of hot, dry summers and mild, wet winters. This regime directly shapes the ecosystem, creating conditions where shrubs thrive. The extended summer drought makes it difficult for large trees to survive due to their substantial water requirements.
Shrubland plants have adaptations to endure these conditions. Many species have developed small, waxy, or tough leaves, known as sclerophyllous foliage, which minimizes water loss through transpiration. To access moisture deep within the soil during the dry season, these plants often possess extensive and deep root systems.
The combination of dry vegetation and hot weather makes the shrubland biome susceptible to fire. Plant communities in these regions are not only adapted to survive periodic fires but, in many cases, rely on them for their life cycle. Some species have seeds that will only germinate after being exposed to the heat of a fire, ensuring their regeneration.
Global Distribution of Shrublands
This climate type is globally recognized as a Mediterranean climate, named after the Mediterranean Basin. However, this ecosystem is not confined to one part of the world.
These conditions are found in four other major regions, all located in similar coastal positions at mid-latitudes. In North America, it is found in California and northwestern Mexico, where the biome is locally known as chaparral. In South America, it occurs in Central Chile, referred to as matorral.
The other two regions are in the Southern Hemisphere. The Western Cape of South Africa is home to a version of this biome called fynbos. In Australia, shrublands are found in the southwestern and parts of the southern regions of the continent.