Responses of Erodium to Varying Microsites: The Role of Germination Cueing

摘要: I examined the role of germination cueing in dynamics Erodium botrys and E. brachycarpum populations exposed to localized, spatial variation within Californian annual grasslands. In laboratory trials, rates both species increased significantly seeds previously fluctuating temperatures (25—45°C) during dry storage. Temperature fluctuations per se were more important than temperature maxima for increasing rates. Light conditions had no significant effect on Field trials also conducted. Summer soil regimes characterized three microsites Erodium: (1) under dense litter grasses, (2) bare soil, (3) mounds created by burrowing pocket gophers. Diurnal surface 17°—51°C 20°—41° litter, 18°—35° gopher mounds. field manipulations release from seed dormancy buried seeds; showed a strong positive relationship between mean diurnal range each microsite. To examine whether accurate predictors suitability site colonization, germinated introduced into microsite type at start growing season. Emergence survival reduced mound microsites; output plant was lower microsites. There colonization success, as measured net reproductive rate, summer temperatures. The accuracy response predicting with drought or heavy grazing. results overall suggest adaptive value species.