都市熱島效應對疣尾蝎虎(Hemidactylus frenatus)生殖效率與活動的影響

Abstract

Abstract Urban areas tend to have higher air temperature than rural areas, especially at night, and this effect is called urban heat island (UHI). Because low temperature may limit the activity and reproduction of nocturnal ectothermic animals, I expect that warming effect of UHI would extend night activity time and increase reproductive efficiency of urban adaptive gecko (Hemidactylus frenatus). In addition to UHI, I also examined the effects of several biotic and abiotic factors, i.e. prey availability, density of coexisting gecko, night lighting condition and building age, on density and activity of gecko. I surveyed the gecko abundance of 40 schools and night activity time of geckos at 14 schools in Taipei from May to December, 2012, calculated monthly UHI intensity (UHII) (mean monthly temperature difference between urban and rural schools at 2 am) of 40 schools based on data collected from the weather stations of these schools, recorded the daily UHII (temperature difference between urban and rural schools at 2 am on the surveyed day) and temperature at 2 am (T2am) based on data loggers I had placed at the 14 schools where I did the survey of geckos’ night activity time, and used the generalized linear model to analyze the correlation between UHII, T2am, other biotic and abiotic factors and reproductive efficiency (juvenile-adult ratio), density and mean activity time of H. frenatus. The results showed that activity time had significant or marginally significant positive correlation with daily UHII in warm months, but in cold month, activity time had significant and marginally significant negative correlation with monthly and daily UHII, respectively. The correlation between juvenile-adult ratio and gecko density with UHII was not significant. However, for the other two coexisting geckos (Hemidactylus bowringii and Gekko hokouensis), UHII had negative correlation with their density in all months. In November when UHII was the weakest, density of two coexisting gecko had negative correlation with activity and density of H. frenatus. Although urban heat island did not significantly benefit the reproduction and density of H. frenatus, it may indirectly benefit H. frenatus via suppressing interspecies competition of the other two coexisting gecko species.