J Environ Qual. 2019 May;48(3):537-548. doi: 10.2134/jeq2018.03.0111.
Soil fauna plays a critical role in various ecosystem processes, but empirical data measuring its impact on greenhouse gas (GHG) emissions from rangelands are limited. We quantified the effects of dung beetles on in situ CO, CH, and NO emissions from simulated cattle dung deposits. Soil in meadows of the semiarid Nebraska Sandhills was treated with three treatments (dung pats with exposure and without exposure to dung beetles, and a no dung control). A closed-chamber method was used to measure GHG fluxes at 0, 1, 2, 3, 7, 10, 14, 21, 28, and 56 d after dung placement in the early season (June-August) and late season (July-September) in 2014 and 2015. The greatest dung beetle abundance was 6 ± 2 beetles per quarter pat on Day 7; the abundance decreased to <2 ± 0.6 on Day 14 and 28 and zero on Day 56. Dung beetles increased fluxes of CO by 0.2 g C d m, NO by 0.4 mg N d m (only in late season 2015), and CH by 0.2 mg C d m. These increases were due to beetle-made macropores that facilitated gas transport in wet dung (initial moisture = 4.6 g g on a dry-weight basis) within 7 d after dung placement. Seasonal environmental differences resulted in greater CO, NO, and CH fluxes in the early season than in the late season. This study concluded that dung beetles increased GHG fluxes from early- and late-season dung deposits on meadows of the semiarid Nebraska Sandhills.
土壤动物在各种生态系统过程中起着至关重要的作用，但衡量其对牧场温室气体（GHG）排放影响的经验数据有限。我们量化了蜣螂对模拟牛粪沉积物中原位 CO、CH 和 NO 排放的影响。在半干旱的内布拉斯加州沙丘草地的草甸中，用三种处理方法处理土壤（暴露和不暴露于蜣螂的粪斑，以及无粪对照）。在 2014 年和 2015 年的早期（6 月至 8 月）和晚期（7 月至 9 月）季节，使用封闭室法在粪肥放置后 0、1、2、3、7、10、14、21、28 和 56 天测量 GHG 通量。最大的蜣螂丰度是第 7 天每四分之一斑 6±2 只；丰度在第 14 天和第 28 天降至<2±0.6，第 56 天为零。蜣螂使 CO 的通量增加了 0.2 g C dm，NO 的通量增加了 0.4 mg N dm（仅在 2015 年的晚期季节），CH 的通量增加了 0.2 mg C dm。这些增加是由于蜣螂制造的大孔，在粪肥放置后 7 天内促进了湿粪（初始水分=干重的 4.6 g g）中的气体传输。季节环境差异导致早季和晚季的 CO、NO 和 CH 通量更大。本研究得出结论，蜣螂增加了半干旱内布拉斯加州沙丘草地早季和晚季粪肥沉积物的 GHG 通量。
