How do barriers like mountains influence species distribution?

Barriers like mountains influence species distribution by creating physical obstacles and varying environmental conditions.

Mountains act as physical barriers that can prevent or limit the movement and dispersal of species, thereby influencing their distribution. This is particularly true for species that are not adapted to high-altitude environments or those that are unable to cross such barriers due to their physical limitations. For instance, many lowland species may find it difficult to cross a mountain range due to the harsh conditions and steep slopes. This can lead to the isolation of populations on either side of the mountain, which can eventually result in speciation due to the lack of gene flow.

In addition to acting as physical barriers, mountains also create a range of environmental conditions that can influence species distribution. As one moves up a mountain, temperature decreases, wind speed increases, and precipitation patterns change. These changes in environmental conditions can create a series of distinct habitats at different altitudes, each with its own unique set of species. For example, the species found in the alpine zone of a mountain (above the tree line) are often very different from those found in the montane zone (below the tree line).

Furthermore, mountains can also influence species distribution on a larger scale by affecting climate patterns. For instance, they can cause orographic rainfall, where air is forced to rise over a mountain, cools and condenses to form rain. This can result in one side of the mountain (the windward side) being much wetter than the other side (the leeward side). This difference in rainfall can create contrasting habitats on either side of the mountain, leading to different sets of species.

In conclusion, mountains play a crucial role in shaping species distribution, both by acting as physical barriers that limit species movement and by creating a variety of environmental conditions that support different sets of species. Understanding these effects is important for predicting how species distributions might change in response to environmental changes, such as climate change.