Today in our environmental science lecture, we're discussing urban green spaces. A recent study in Melbourne tracked the effects of adding rooftop gardens to city buildings. The researchers measured temperature, air quality, and biodiversity over two years. They found that rooftop gardens reduced local temperatures by up to 3 degrees Celsius in summer, but only when the gardens covered at least 60% of the roof area. Additionally, bird species increased by 15% in areas within 500 meters of these gardens. However, the study noted that maintenance costs were higher than expected, mainly due to irrigation needs. The key takeaway is that green roofs require careful planning to maximize benefits.
❓ What does the study suggest about the effectiveness of rooftop gardens?
A. A. They reduce temperatures only if a minimum roof area is covered.
B. B. They increase bird species regardless of garden size.
C. C. They are cost-effective due to low maintenance needs.
D. D. They have no impact on air quality.
✅ 正确答案
A. They reduce temperatures only if a minimum roof area is covered.