Reproductive Characteristics of a Populus euphratica Population and Prospects for Its Restoration in China

Abstract

Populus euphratica is a dominant tree in riparian ecosystems in arid areas of northwest China, but it fails to regenerate in these systems. This study evaluates causes for the failure of sexual and asexual regeneration of this species in the wild. P. euphratica disperses as many as 85743 seeds/m2 during summer, and the seeds germinate to 92.0% in distilled water and to 60.8% on silt. However, very few seeds (3.6%) can germinate on unflooded soil. The seed-rain season is prolonged by temporal variability in seed dispersal among individuals, which ensures that seedling emergence can occur during favorable conditions (i.e., floods and rainfall). As a result of water shortage and river channeling due to water usage and altered river flows, there are no safe sites on river banks for seed germination, which has led to the failure of P. euphratica to regenerate from seed. Root suckers of P. euphratica were present in 86% of the forest gaps investigated. However, extensive grazing has destroyed many of them and thus has reduced this form of regeneration. This research suggests that human activities are resulting in the failure of P. euphratica to regenerate. Changes in land management such as reduced use of concrete canals in Populus forests and/or reduced sheep grazing in these areas may promote their regeneration.

Speciation of two desert poplar species triggered by Pleistocene climatic oscillations

“…In a recent study of P. euphratica, reproductive characteristics in 20 stands from Xinjiang the mean age of the trees was 15.4 years with an average s.d. of 2.6 (Cao et al, 2012). Assuming that the stands were a random sample that would imply that our estimates of generation time may not be strongly off the mark.…”

Regeneration properties of a Populus euphratica riparian forest located in the vicinity of the Ejina Oasis, Inner Mongolia, China

“…In addition, residents have over-cultivated and overgrazed animals in these P. euphratica forests for many years. As a result, most of the P. euphratica forests in the Ejina Oasis have been negatively impacted and failed to regenerate either sexually or asexually (Cao et al 2012). To restore P. euphratica forests in the Ejina Oasis, it is necessary to draw off water regularly from reservoirs in the middle reaches every year.…”

“…In addition, local people have over-cultivated and overgrazed animals in these P. euphratica forests for many years. As a result, most of the P. euphratica forests in the Ejina Oasis have been negatively impacted and failed to regenerate either sexually or asexually (Cao et al 2012). Successful regeneration is essential for a forest to construct a good structure to stay healthy, and restore and maintain its dynamic stability (D'Amato et al 2009;Gauthier et al 2015;Nyland et al 2006), so it is important and necessary to understand the regeneration of P. euphratica.…”

Peer Review #2 of "Effects of root phenotypic changes on the deep rooting of Populus euphratica seedlings under drought stresses (v0.1)"

“…Manuscript to be reviewed during the early stages, meaning that under the harsh environments in arid regions, P. euphratica can only propagate generatively in the freshly deposited floodplain soils from May to August (Cao et al, 2012). Even so, the optimal soil conditions in such floodplains for seedling germination and growth only exist for a short time, as the surface soil post-flood rapidly becomes increasingly dry and salty due to evaporation.…”