Influences of Plateau Zokor Burrowing on Soil Erosion and Nutrient Loss in Alpine Meadows in the Yellow River Source Zone of West China

Abstract

Plateau zokors (Eospalax baileyi) are an agent actively involved in causing soil erosion and meadow degradation in the Yellow River Source Zone of West China. This study aims to quantify the amount of soil and nutrient loss from zokor mounds in relation to slope gradient and rainfall intensity, and to assess the amount of soil loss in zokor-infested areas compared with healthy meadows in Henan County, Qinghai Province. The results showed that zokor mounds were gradually lowered at a rate of 1.8–3.9 cm h−1. Soil loss occurred two min after the rain began, reaching the maximum level during the first 20 min. The rate of soil loss and nutrient loss increased with the rainfall intensity and slope gradient. When the rainfall intensity rose from 5 to 10 mm h−1, and from 10 to 15 mm h−1, the total soil loss on 10° slopes increased by 2.5 times and 3.9 times, respectively, and soil nutrient loss increased by 1.7 times and 2.7 times, respectively. As the slope gradient steepened to 20°, the corresponding figures were 2.8 times and 4.3 times for total soil loss, and 1.8 times and 2.9 times, respectively, for soil nutrient loss. When the slope rose to 30°, the soil loss increased by 3.0 and 4.5 times, and the soil nutrient loss increased by 1.8 times and 3.1 times, respectively. There was a power function between soil loss and surface runoff (S = 0.2371Q2.2307, R2 = 0.9529). The soil was eroded at a rate of 256.6 g m−2 h−1 from zokor mounds, 17.7 times higher than in intact meadows, and 1.8 times higher than in partially recovered meadows. Most of the eroded soils had a mean diameter of 0–1.2 mm. It is recommended that artificial control of plateau zokors should be implemented, together with other ecological restoration measures to restrain the soil erosion problem caused by zokor activities.

Higher sediment redistribution rates related to burrowing animals than previously assumed as revealed by time-of-flight-based monitoring

“…These studies relied on applying tests under laboratory conditions using rainfall simulators; conducting several field campaigns weeks to months apart; or measuring the volume of excavated or eroded sediment in the field using instruments such as erosion pins, splash boards, or simple rulers (Imeson and Kwaad, 1976;Reichman and Seabloom, 2002;Wei et al, 2007;Le Hir et al, 2007;Li et al, 2018;T. C. Li et al, 2019;Voiculescu et al, 2019;Chen et al, 2021;Übernickel et al, 2021b;G. Li et al, 2019).…”

Time-Of-Flight monitoring reveals higher sediment redistribution rates related to burrowing animals than previously assumed

“…Previous studies estimated both positive as well as negative impacts of burrowing animals on sediment redistribution rates. The results were obtained by applying tests under laboratory conditions using rainfall simulators, conducting several field campaigns weeks to months apart, or by measuring the volume of excavated or eroded sediment in the field using methods such as erosion pins, splash boards, or simple rulers (Imeson and Kwaad, 1976;Reichman and Seabloom, 2002;Wei et al, 2007;Le Hir et al, 2007;Li et al, 2018;Li et al, 2019c;Li et al, 2019b;Voiculescu et al, 2019;Chen et al, 2021;Übernickel et al, 2021b;Li et al, 2019a). Although burrowing animals are generally seen as ecosystem engineers (Gabet et al, 2003;Wilkinson et al, 2009), their role in soil erosion, in general, and for numerical soil erosion models, in particular, is, to date, limited to predictions of the burrow locations and particle mixing at these locations (Black and Montgomery, 1991;Meysman et al, 2003;Yoo et al, 2005;Schiffers et al, 2011).…”

Soil Water Erosion and Its Hydrodynamic Characteristics in Degraded Bald Patches of Alpine Meadows in the Yellow River Source Area, Western China

“…In addition, plateau zokors (Eospalax baileyi) and plateau pika (Ochotona curzoniae) are abundant in the Yellow River source area [19]. As essential sources of biological disturbance in alpine meadow ecosystems, their digging and gnawing behaviors not only have a significant impact on vegetation and soil [20][21][22], but the loose mounds formed by their mounding can also directly form secondary bald patches of bare ground, as well as provide material sources for soil erosion [23][24][25]. Many scholars have shown that meadow degradation is closely related to the degree of development of bald patches, and soil erosion after meadow degradation positively influences further soil erosion and meadow degradation [26][27][28].…”