Today in our environmental science lecture, we'll discuss the impact of urban green spaces. Recent studies show that adding parks and community gardens can significantly reduce the 'heat island' effect in cities. For example, a study in Melbourne found that tree-lined streets can lower surface temperatures by up to 5 degrees Celsius during summer afternoons. However, the benefits depend on the type of vegetation. Native species, which require less water, are more effective in dry climates. In contrast, non-native ornamental plants might provide shade but often consume excessive water, leading to higher maintenance costs. Therefore, urban planners should prioritize native plantings not only for temperature regulation but also for biodiversity support.