Responses and resilience of tallgrass prairie streams to patch‐burn grazing

Abstract

Patch‐burn grazing (PBG) can promote terrestrial heterogeneity and biodiversity, but can temporarily increase stream nutrients and ecosystem metabolism, and alter macroinvertebrate assemblages. The impacts of grazing on stream channel morphology and post‐PBG recovery patterns are unclear. We assessed the influence of grazing in PBG managed grassland streams in Missouri, USA, and subsequent recovery when grazing ceased for 2 years. We hypothesized that grazing would degrade water quality, stream biotic integrity and channel morphology, but that riparian fencing would mitigate these effects. We predicted that biological and chemical variables in unfenced streams would return to pre‐PBG levels within 2 years after grazing ceased, but channel morphology would not. Six small headwater streams (two in ungrazed control watersheds, two in PBG watersheds with 10 m fenced riparian zones and two in PBG unfenced) were sampled over 7 years; 2 years before PBG, 3 years during PBG and 2 years post‐PBG. We sampled macroinvertebrates and water chemistry monthly when water was present and surveyed channel morphology at least once each study period. During grazing, unfenced watersheds showed the greatest changes in channel width, depth and area. During the post‐PBG period, one of the two unfenced watersheds showed partial recovery of channel morphology. Although grazing increased concentrations of nutrients and chlorophyll‐a, concentrations returned to pre‐PBG conditions after grazing ceased, indicating recovery. Very fine organic sediments increased in the unfenced watersheds compared to the control during grazing but recovered afterwards. Contributions of Chironomidae to total invertebrate abundance increased in the unfenced watersheds during grazing, and then decreased during the post‐PBG period. Riparian fencing mostly mitigated effects of grazing on the streams. Unfenced streams were resilient to effects of grazing in a PBG managed grassland, with most metrics recovering within 2 years after grazing ceased, except for channel morphology. Synthesis and applications. Grazing in a patch‐burn grazed managed grassland coupled with riparian fencing could be an effective conservation tool for land managers of prairies, with relatively modest influences on stream water quality and biotic integrity. Persistent changes in stream channel morphology and effects of longer periods of grazing deserve further research.

Precipitation regulates the livestock dung seed bank through above ground vegetation productivity in the Qaidam basin

“…For example, in grazing ecosystems, because of livestock feeding preferences, a large number of plant seeds accumulate in faeces (the ‘fertile island effect’) (Cai et al, 2020). The heterogeneity in the composition between the DSB and that of AGV indicates that the DSB is a potential driving force for the formation of grassland patching due to grazing (Fulgoni et al, 2020; Wang & Hou, 2021a, 2021b; Yu et al, 2012; Yu, Xu, Wang, Shang, & Long, 2013). Moreover, in arid environments such as the desert grassland of the study site, seed dispersal via dung pellets provides substantial protection for seeds until sufficient rainfall occurs to allow germination and seedling establishment, thus representing an adaptation for survival in this type of harsh environment.…”

Best Practices in River Water Restorations from Industrial Pollutions in Developing Countries

“…Although managers often try to reconstruct morphology, recovery of flow dynamics is less likely [19]. However, the restoration of their morphology is necessary for the restoration of services offered by ecosystems that are associated with flowing waters [20] River systems are complex and depend on what lies within them, their history, and the environment [21]. Therefore, to achieve ecologically efficient river restoration within the constraints imposed by anthropogenic systems, the principles of ecological restoration must be incorporated into the restoration process.…”

The Impacts of Different Anthropogenic Disturbances on Macroinvertebrate Community Structure and Functional Traits of Glacier-Fed Streams in the Tianshan Mountains

“…Natural grasslands constitute the main source of forage for livestock. The impacts of grazing on stream ecosystems include changes in nutrient load [28], changes in hydrology (e.g., flow regime, predictability, and water quantity) [29], and erosion processes that result in soil loss and sediment inputs to streams [30]. Livestock trampling the riverbed destroys habitats for benthic organisms [31].…”