Zokor activity promotes soil water infiltration in the Mu Us sandy land of northern Shaanxi,China

Zokors are common subterranean rodents that inhabit agricultural fields, shrublands, and grasslands in the arid and semi-arid regions of China. Zokor burrowing activities can alter soil structure and affect soil hydrological processes;however, there are few studies regarding their effects on soil preferential flow in the Mu Us sandy land. An evaluation of the effects of zokor disturbance on their habitat and soil water is important for understanding the ecological role of zokors in the soil ecosystem of the Mu Us sandy land. A field dye-tracing experiment was conducted in the Gechougou watershed on the southeastern edge of the Mu Us sandy land to investigate the effect of zokor burrowing activity on soil preferential flow characteristics. Our results showed that the density of zokor tunnels was the highest(0.40–0.46 m m^(-2)) under 30%–50% vegetation coverage and that the tunnels were approximately 3 cm from the surface.Both stained area ratio and stained path number were higher at sites with zokors than without zokors. Stained path widths were 10–80 and > 80 mm at zokor-harboring sites exhibiting homogeneous flow and heterogeneous finger flow, respectively. In the absence of zokors, homogeneous flow and highly interacted macropore flow were predominant. Soil water content below the zokor tunnels was higher than that above the tunnels. Moderate disturbance of soil structure by zokor activity facilitated soil water infiltration. These results enabled a better understanding of the effect of soil fauna on soil structure and hydrological processes and provided recommendations for ecological construction and renovation in arid and semi-arid regions.

Antifertility effects of levonorgestrel,quinestrol,and their mixture(EP-1)on plateau zokor in the Qinghai–Tibetan Plateau

The plateau zokor(Eospalax baileyi)is a key species in the Qinghai-Tibetan Plateau ecosystem,and fertility control could be an ideal approach to manage populations of this subterranean species.In this laboratory study,we explored the effects of the mixture of levonorgestrel and quinestrol(EP-1,1:2),quinestrol(E),and levonorgestrel(P)on the reproductive status of plateau zokors.Groups of 5 animals of each sex were treated with different concentrations of EP-1(1,5,and 10 mg/kg),E(0.33,3.3,and 6.6 mg/kg),and P(0.67,3.35,and 6.7 mg/kg)by oral gavage over 7 successive days and killed on day 15.Body mass reduction was observed in the EP-1 and E groups.EP-1 and E significantly reduced the weight of testis and epididymis at 10 and 3.3 mg/kg,respectively.Sperm count and motility were significantly reduced by 5 mg/kg EP-1 and 0.33 mg/kg E.The levels of serum testosterone,estradiol,luteinizing hormone,and follicle stimulating hormone were significantly reduced by 5 mg/kg EP-1 and 3.3 mg/kg E.EP-1 and E significantly increased the uterine and ovarian weights at 10 and 3.3 mg/kg,respectively.In the plateau zokors,treatment with P had no influence on the reproductive status.These data demonstrate that EP-1 and E have an inhibitory effect on a range of reproductive parameters in the plateau zokors.Further assessment is required to determine the effects on breeding and recruitment in enclosure orfield experiments.

Antioxidant response to severe hypoxia in Brandt’s vole Lasiopodomys brandtii

The antioxidant defense system is essential for animals to cope with homeostasis disruption and overcome oxidative stress caused by adverse environmental conditions such as hypoxia.However,our understanding of how this system works in subterranean rodents remains limited.In this study,Brandt’s vole Lasiopodomys brandtii was exposed to normoxia(21%O_(2))or hypoxia(mild or severe hypoxia:10%or 5%O_(2))for 6 h.Changes in key enzymes of the classic enzymatic antioxidant system at both mRNA and enzyme activity levels,and tissue antioxidant levels of the low-molecular-weight antioxidant system were determined in brain,liver,and kidney.Transcript levels of the upstream regulator NF-E2-related factor 2(Nrf2)were also measured.We found that the mRNA expression of Nrf2 and its downstream antioxidant enzyme genes in L.brandtii were relatively conserved in response to hypoxia in most tissues and genes tested,except in the liver.Hepatic Nrf2,Cu/Zn SOD,GPx1,and GPx3 levels were significantly upregulated in response to mild hypoxia,whereas Mn SOD level decreased significantly in severe hypoxia.Unmatched with changes at the RNA level,constitutively high and relatively stable antioxidant enzyme activities were maintained throughout.For the low-molecular-weight antioxidant system,an abrupt increase of cerebral ascorbic acid(AA)levels in hypoxia indicated a tissue-specific antioxidant response.Although hypoxia did not cause significant oxidative damage in most tissues tested,the significant decrease in antioxidant enzyme activities(GPX and GR)and increase in lipid peroxidation in the kidney suggest that prolonged hypoxia may pose a critical threat to this species.