CSIRO Land and Water Flagship, Australia.
Environmental Studies Department, University of California, Santa Cruz, United States.
Sci Total Environ. 2018 Jan 1;610-611:570-575. doi: 10.1016/j.scitotenv.2017.08.091. Epub 2017 Aug 17.
Urban gardens in Central California are highly vulnerable to the effects of climate change, experiencing both extended high heat periods as well as water restrictions because of severe drought conditions. This puts these critical community-based food production systems at risk as California is expected to experience increasing weather extremes. In agricultural systems, increased vegetation complexity, such as greater structure or biodiversity, can increase the resilience of food production systems from climate fluctuations. We test this theory in 15 urban gardens across California's Central Coast. Local- and landscape-scale measures of ground, vegetation, and land cover were collected in and around each garden, while climate loggers recorded temperatures in each garden in 30min increments. Multivariate analyses, using county as a random factor, show that both local- and landscape-scale factors were important. All factors were significant predictors of mean temperature. Tallest vegetation, tree/shrub species richness, grass cover, mulch cover, and landscape level agricultural cover were cooling factors; in contrast, garden size, garden age, rock cover, herbaceous species richness, and landscape level urban cover were warming factors. Results were similar for the maximum temperature analysis except that agriculture land cover and herbaceous species richness were not significant predictors of maximum temperature. Analysis of gardener watering behavior to observed temperatures shows that garden microclimate was significantly related to the number of minutes watered as well as the number of liters of water used per watering event. Thus gardeners seem to respond to garden microclimate in their watering behavior even though this behavior is most probably motivated by a range of other factors such as water regulations and time availability. This research shows that local management of ground cover and vegetation can reduce mean and maximum temperatures in gardens, and the reduced temperatures may influence watering behavior of gardeners.
加利福尼亚中部的城市花园极易受到气候变化的影响，由于严重的干旱条件，这些城市花园不仅经历了长时间的高温期，还面临着水资源限制。随着加利福尼亚州预计将出现越来越多的极端天气，这些关键的社区粮食生产系统面临着风险。在农业系统中，增加植被的复杂性，如增加结构或生物多样性，可以提高粮食生产系统对气候波动的恢复能力。我们在加利福尼亚州中部海岸的 15 个城市花园中测试了这一理论。在每个花园内及其周围收集了地面、植被和土地覆盖的本地和景观尺度测量数据，而气候记录仪则以 30 分钟的增量记录每个花园的温度。使用县作为随机因素的多元分析表明，本地和景观尺度因素都很重要。所有因素都是平均温度的重要预测因子。最高植被、树木/灌木物种丰富度、草地覆盖率、覆盖物覆盖率和景观水平农业覆盖率是降温因素；相比之下，花园面积、花园年龄、岩石覆盖率、草本物种丰富度和景观水平城市覆盖率是升温因素。最高温度分析的结果相似，只是农业土地覆盖率和草本物种丰富度不是最高温度的显著预测因子。对园丁观察到的浇水行为与温度的分析表明，花园小气候与浇水的分钟数以及每次浇水的用水量显著相关。因此，园丁们似乎会根据花园小气候来调整浇水行为，尽管这种行为可能是由一系列其他因素引起的，如用水规定和时间可用性。这项研究表明，对地面覆盖物和植被的本地管理可以降低花园的平均和最高温度，而降低的温度可能会影响园丁的浇水行为。
