scholarly journals Life history response of Echinops gmelinii Turcz. to variation in the rainfall pattern in a temperate desert

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8159
Author(s):  
Yanli Wang ◽  
Xinrong Li ◽  
Lichao Liu ◽  
Jiecai Zhao ◽  
Jingyao Sun
Keyword(s):  
Life History ◽  
Seedling Survival ◽  
Seed Mass ◽  
Rainfall Amount ◽  
Future Climate Change ◽  
Rainfall Events ◽  
Life History Response ◽  
Temperate Desert ◽  
Winter Annual ◽  
Growth And Reproduction

Background Current and future changes in rainfall amount and frequency may particularly impact annual plants in desert ecosystems. The winter annual Echinops gmelinii Turcz. is widely distributed in the desert habitats of northern China and is a dominant pioneer annual plant following sand stabilization in the Tengger Desert. This species plays a vital role in dune stabilization during spring and early summer, when wind erosion is the most severe and frequent. However, seedling emergence and regeneration in sandy soil are mainly determined by rainfall patterns. Therefore, understanding the life history response of this species to rainfall variation is necessary for understanding the change of population dynamics under the future climate change. Methods A field simulation rainfall pot experiment using rainout shelter was conducted that included five amounts and five frequencies of rainfall based on historical and predicted values to monitor the life history responses of E. gmelinii in a near-natural habitat. Results We found that rainfall amount and frequency significantly affected seedling survival, growth and reproduction. The plant height, biomass, capitula number, seed number, seed mass and reproductive effort, but not the root/shoot ratio, significantly increased with increasing rainfall. Further, these traits exhibited the greatest response to low-frequency and larger rainfall events, especially the optimal rainfall frequency of 10-day intervals. Offspring seed germination showed increasing trends with decreasing rainfall, suggesting that the maternal effects may have occurred. Conclusions Our study shows that the plasticity in growth and reproduction of E. gmelinii in response to rainfall variations may help it to gain dominance in the harsh and unpredictable desert environment. Furthermore, population development of this winter annual species should be promoted under the likely future scenarios of large rainfall events and increasing cool-season precipitation in temperate desert.

Growth and reproduction of the red alga Rhodomela larix

1986 ◽  
Vol 64 (7) ◽  
pp. 1499-1506 ◽  
Author(s):  
Carla D'Antonio
Keyword(s):  
Life History ◽  
Red Alga ◽  
Oregon Coast ◽  
Perennial Plants ◽  
History Of ◽  
Lower Site ◽  
Intertidal Site ◽  
Observation Period ◽  
Growth And Reproduction

Components of the growth and life history of the red alga Rhodomela larix (Turner) C. Agardh were studied during an 18-month period at a high intertidal and a low intertidal site on the central Oregon coast. Growth was measured by following (i) individually marked upright axes, (ii) clumps of axes thought to represent individual plants, and (iii) large patches of R. larix. Variation in size and growth was common among axes, and portions of some axes were clearly perennial. Plants grew most rapidly in the spring and summer (up to 1.2 mm/day) with a large amount of variation occurring between and within zones and among seasons. Overall, plants at the higher site were shorter and had fewer branches during most of the year than plants at the lower site. Gametophytes were more common in the higher site, while tetrasporophytes predominated at both sites. Reproductive axes were present throughout the observation period, although little recruitment of sexual propagules was seen, implying that populations may be maintained by vegetative perennation of individual plants.

scholarly journals Rainfall-runoff relationships at event scale in western Mediterranean ephemeral streams

2021 ◽  
Author(s):  
Roberto Serrano-Notivoli ◽  
Alberto Martínez-Salvador ◽  
Rafael García-Lorenzo ◽  
David Espín-Sánchez ◽  
Carmelo Conesa-García
Keyword(s):  
Western Mediterranean ◽  
Additive Models ◽  
Future Climate Change ◽  
Ephemeral Streams ◽  
Return Periods ◽  
Rainfall Runoff ◽  
Event Scale ◽  
Rainfall Events ◽  
Flow Generation ◽  
Terrain Characteristics

Abstract. Ephemeral streams are highly dependent on rainfall and terrain characteristics and, therefore, very sensitive to minor changes in these environments. Western Mediterranean area exhibits a highly irregular precipitation regime with a great variety of rainfall events driving the flow generation on intermittent watercourses, and future climate change scenarios depict a lower magnitude and higher intensity of precipitation in this area, potentially leading to severe changes in flows. We explored the rainfall-runoff relationships in two semiarid watersheds in southern Spain (Algeciras and Upper Mula) to model the different types of rainfall events required to generate new flow in both intermittent streams. We used a nonlinear approach through Generalized Additive Models at event scale in terms of magnitude, duration, and intensity, contextualizing resulting thresholds in a long-term perspective through the calculation of return periods. Results showed that the average ~ 1.2-day and <1.5 mm event was not enough to create new flows. At least a 4-day event ranging from 4 to 20 mm, depending on the watershed was needed to ensure new flow at a high probability (95 %). While these thresholds represented low return periods (from 4 to 10 years), the great irregularity of annual precipitation and rainfall characteristics, makes prediction highly uncertain. Almost a third part of the rainfall events resulted in similar or lower flow than previous day, emphasizing the importance of lithological and terrain characteristics that lead to differences in flow generation between the watersheds.

Individual Growth and Reproduction

2019 ◽  
pp. 38-56
Author(s):  
Ken H. Andersen
Keyword(s):  
Life History ◽  
Growth Model ◽  
Life Histories ◽  
Maximum Size ◽  
Individual Growth ◽  
Energy Budgets ◽  
Asymptotic Size ◽  
The Individual ◽  
Growth And Reproduction

This chapter develops descriptions of how individuals grow and reproduce. More specifically, the chapter seeks to determine the growth and reproduction rates from the consumption rate, by developing an energy budget of the individual as a function of size. To that end, the chapter addresses the question of how an individual makes use of the energy acquired from consumption. It sets up the energy budgets of individuals by formulating the growth model using so-called life-history invariants, which are parameters that do not vary systematically between species. While the formulation of the growth model in terms of life-history invariants is largely successful, there is in particular one parameter that is not invariant between life histories: the asymptotic size (maximum size) of individuals in the population. This parameter plays the role of a master trait that characterizes most of the variation between life histories.

scholarly journals Individual Rainfall Change Based on Observed Hourly Precipitation Records on the Chinese Loess Plateau from 1983 to 2012

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2268
Author(s):  
Wenbin Ding ◽  
Fei Wang ◽  
Kai Jin ◽  
Jianqiao Han ◽  
Qiang Yu ◽  
...  
Keyword(s):  
Loess Plateau ◽  
Heavy Rainfall ◽  
Rainfall Intensity ◽  
Rainfall Amount ◽  
The Loess Plateau ◽  
Total Rainfall ◽  
Rainfall Events ◽  
Rainfall Duration ◽  
Rainfall Frequency ◽  
Annual Total

The magnitude and spatiotemporal distribution of precipitation are the main drivers of hydrologic and agricultural processes in soil moisture, runoff generation, soil erosion, vegetation growth and agriculture activities on the Loess Plateau (LP). This study detects the spatiotemporal variations of individual rainfall events during a rainy season (RS) from May to September based on the hourly precipitation data measured at 87 stations on the LP from 1983 to 2012. The incidence and contribution rates were calculated for all classes of rainfall duration and intensity to identify the dominant contribution to the rainfall amount and frequency variations. The trend rates of regional mean annual total rainfall amount (ATR) and annual mean rainfall intensity (ARI) were 0.43 mm/year and 0.002 mm/h/year in the RS for 1983–2012, respectively. However, the regional mean annual total rainfall frequency (ARF) and rainfall events (ATE) were −0.27 h/year and −0.11 times/year, respectively. In terms of spatial patterns, an increase in ATR appeared in most areas except for the southwest, while the ARI increased throughout the study region, with particularly higher values in the northwest and southeast. Areas of decreasing ARF occurred mainly in the northwest and central south of the LP, while ATE was found in most areas except for the northeast. Short-duration (≤6 h) and light rainfall events occurred mostly on the LP, accounting for 69.89% and 72.48% of total rainfall events, respectively. Long-duration (≥7 h) and moderate rainfall events contributed to the total rainfall amount by 70.64% and 66.73% of the total rainfall amount, respectively. Rainfall frequency contributed the most to the variations of rainfall amount for light and moderate rainfall events, while rainfall intensity played an important role in heavy rainfall and rainstorms. The variation in rainfall frequency for moderate rainfall, heavy rainfall, and rainstorms is mainly affected by rainfall duration, while rainfall event was identified as a critical factor for light rainfall. The characteristics in rainfall variations on the Loess Plateau revealed in this study can provide useful information for sustainable water resources management and plans.

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