scholarly journals Impact of grazing intensities on reproduction patterns of elm trees (Ulmus pumila) in degraded sandy lands in China

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9013 ◽  
Author(s):  
Yi Tang

The effect of grazing on patterns of reproduction in trees has been little reported. We explored the effects of grazing intensities on reproductive growth, allocation patterns, and duration in elm trees (Ulmus pumila L.) at the Horqin Sandy Land, a degraded area in northern China. Current-year shoots were selected from branches and harvested from individual elm trees subjected to one of four grazing intensities (heavy, moderate, light, and no grazing). Shoots, flower buds, flowers, seeds, leaf buds, and leaves were collected, dried, and weighed. Results showed that the biomass in heavy, moderate and light grazing treatments is significantly higher than in no grazing treatment (P < 0.05). The reproductive allocation of U. pumila in heavy grazing treatment was significantly higher from that in the no grazing treatment (P < 0.05). Additionally, we found that reproduction of U. pumila ended later in grazed plots, suggesting the duration of reproduction is extended with grazing disturbance. Our findings suggest that U. pumila may prolong it s duration of reproduction and alter its reproductive biomass in response to grazing. It is not clear whether these effects are related to damage to U. pumila trees by grazers or whether they are due to grazers affecting soil properties or plant competitors around U. pumila trees.

Trees ◽  
2013 ◽  
Vol 28 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Hua Su ◽  
Yonggeng Li ◽  
Wei Liu ◽  
Hong Xu ◽  
Osbert Jianxin Sun

2021 ◽  
Vol 127 ◽  
pp. 107599
Author(s):  
Hanbing Zhang ◽  
Jian Peng ◽  
Chaonan Zhao ◽  
Zihan Xu ◽  
Jianquan Dong ◽  
...  

Solid Earth ◽  
2016 ◽  
Vol 7 (4) ◽  
pp. 1085-1094 ◽  
Author(s):  
Jiao Tang ◽  
Carlos Alberto Busso ◽  
Deming Jiang ◽  
Ala Musa ◽  
Dafu Wu ◽  
...  

Abstract. As a native tree species, Ulmus pumila var. sabulosa (sandy elm) is widely distributed in the Horqin Sandy Land, China. However, seedlings of this species have to withstand various depths of sand burial after emergence because of increasing soil degradation, which is mainly caused by overgrazing, climate change, and wind erosion. An experiment was conducted to evaluate the changes in its survivorship, morphological traits, and biomass allocation when seedlings were buried at different burial depths: unburied controls and seedlings buried vertically up to 33, 67, 100, or 133 % of their initial mean seedling height. The results showed that partial sand burial treatments (i.e., less than 67 % burial) did not reduce seedling survivorship, which still reached 100 %. However, seedling mortality increased when sand burial was equal to or greater than 100 %. In comparison with the control treatment, seedling height and stem diameter increased at least by 6 and 14 % with partial burial, respectively. In the meantime, seedling taproot length, total biomass, and relative mass growth rates were at least enhanced by 10, 15.6, and 27.6 %, respectively, with the partial sand burial treatment. Furthermore, sand burial decreased total leaf area and changed biomass allocation in seedlings, partitioning more biomass to aboveground organs (e.g., leaves) and less to belowground parts (roots). Complete sand burial after seedling emergence inhibited its re-emergence and growth, even leading to death. Our findings indicated that seedlings of sandy elm showed some resistance to partial sand burial and were adapted to sandy environments from an evolutionary perspective. The negative effect of excessive sand burial after seedling emergence might help in understanding failures in recruitments of sparse elm in the study region.


Geoderma ◽  
2020 ◽  
Vol 363 ◽  
pp. 114146
Author(s):  
Yong-Sheng Wu ◽  
Xin-Rong Li ◽  
Hasi-Eerdun ◽  
Rui-Ping Yin ◽  
Tie-Jun Liu

Author(s):  
Jinsheng Li ◽  
Jianying Shang ◽  
Ding Huang ◽  
Shiming Tang ◽  
Tianci Zhao ◽  
...  

The distribution of soil particle sizes is closely related to soil health condition. In this study, grasslands under different grazing intensities and different cultivation ages grasslands were selected to evaluate the dynamics of soil particle size redistribution in different soil layers. When the grazing intensity increased, the percentage of 2000~150-μm soil particles in the 0–10-cm soil layer decreased; 150~53-μm soil particles remained relatively stable among the grazing intensities—approximately 28.52%~35.39%. However, the percentage of less than 53-μm soil particles increased. In cultivated grasslands, the larger sizes (>53 μm) of soil particles increased and the smaller sizes (<53 μm) decreased significantly (p < 0.05) in the 0–10 cm-soil layer with increasing cultivation ages. The increase in small soil particles (<53 μm) in topsoil associated with grazing intensity increased the potential risk of further degradation by wind erosion. The increase in big soil particles (>53 μm) in topsoil associated with cultivation ages decreased the soil capacity of holding water and nutrient. Therefore, to maintain the sustainability of grassland uses, grazing grasslands need to avoid heavy grazing, and cultivated grasslands need to change current cultivation practices.


2020 ◽  
Vol 461 ◽  
pp. 117980 ◽  
Author(s):  
Ming-Yong Li ◽  
Li-Dong Fang ◽  
Chun-Yang Duan ◽  
Yu Cao ◽  
Hong Yin ◽  
...  

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