The role of seedling recruitment from juvenile populations of Carex brevicuspis (Cyperaceae) at the Dongting Lake wetlands, China

Abstract

Seedlings and vegetative ramets may contribute differentially to the recruitment of clonal populations in different growth phases, but this has rarely been investigated. In this study, we quantified the number and survivorship of seedlings and vegetative ramets monthly in juvenile and mature populations of Carex brevicuspis. During the first growing season after flooding (from October to January), 9 seedlings m−2 (13% of all established shoots) were found in juvenile populations, while no seedlings were found in mature populations. During the second growing season before flooding (from February to May), no new seedling recruits were found either in juvenile or in mature populations. All shoots of seedlings were withered during the dormant season (January and February), but 62.5% seedlings could produce vegetative ramets in the following growing season. During the dormant season, all the early emerging ramets (sprouted in October) withered, but the later emerging ones (sprouted in November and December) survived in both mature and juvenile populations. These results indicated that seedling recruitment was only apparent in juvenile populations of C. brevicuspis. The genetic diversity in mature C. brevicuspis populations may be established in juvenile populations by seedling recruitment, and sustained in mature populations by vegetative reproduction.

Trade-off between allocation to reproductive ramets and rhizome buds in Carex brevicuspis populations along a small-scale elevational gradient

“…C. brevicuspis significantly invests in sexual reproduction through flowering and seed production, particularly at low-elevation sites. However, population recruitment of C. brevicuspis occurs from belowground buds rather than from seeds 21 22 25 . Clonal species, for which local recruitment mainly depends on vegetative propagation, allocate more nutrients to sexual reproduction when the ramet density becomes high, because the additional clonally produced individuals have a low probability of survival in the local area 3 28 .…”

“…In disturbed environments, clonal plants may allocate more resources to sexual reproduction as a survival mechanism 4 31 . Seeds produced at low-elevation sites may also have a greater chance of dispersal by floodwater and of establishment in bare beaches 22 .…”

“…New ramets sprout in March, after which plants grow rapidly. Plants flower and fruit from March to May, but seedlings are scarce in the field 21 22 .…”

“…C. brevicuspis is a typical rhizomatous clonal plant that is widely distributed in the study area 19 20 . It reproduces sexually through seeds and asexually via rhizome buds 21 22 . In freshwater wetlands or floodplains, the elevation, which closely reflects the hydrological and edaphic conditions at which plants occur, is the most important factor affecting plant growth, reproduction, and distribution 20 23 24 25 26 .…”

Estimating the biomass of Carex cinerascens (Cyperaceae) in floodplain wetlands in Poyang Lake, China

“…Depending on the hydrological characteristics of Poyang Lake, C. cinerascens usually has two growing seasons in a year. In autumn (September or October) after the flood recession when the soil is exposed, the C. cinerascens shoots begin to grow and continue until winter (January of the following year) when the aboveground plant parts become withered because of the cold temperatures, this is called the "autumn grass" (Deng et al 2015). C. cinerascens is the dominant community in Baisha Lake and is widely distributed in the experimental area.…”