The invasion of exotic annual grasses including cheatgrass medusahead and North Africa grass have drastically altered grassland ecosystems across the western United States. Continuous efforts have been made to reclaim these ecosystems through the application of annual grass selective herbicides. The effectiveness of these herbicides and the response of vegetation post application is well documented, but research is lacking in how these treatments directly affect mule deer forage quality, quantity, and composition throughout the year. Our objectives were to evaluate the efficacy of using imazapic (Open Range G, Wilbur-Ellis) to improve summer mule deer forage and assess the potential negative effects of the herbicide on winter forage availability. In fall of 2020, imazapic was applied to fifteen, 8-ha plots established within telemetered mule deer home ranges located in grassland habitat surrounding Heppner, Oregon, United States. Paired treatment and control plots were monitored for 2 yr in the summer and fall of 2021 and summer of 2022. Our results suggest that imazapic applications can be used to increase the nutritional quality of forage but may temporarily reduce the quantity of forage available in the first summer after treatment. In the second summer, forage biomass increased significantly but crude protein and digestible energy contents of forage were no longer superior within treatment plots. Imazapic applications had no effect on winter forage biomass or nutritional quality of forage available. Imazapic treatments appear to be an effective strategy to improve summer mule deer forage quality and quantity without adversely affecting winter food sources.

中文翻译：

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评估甲马烟处理对黑尾鹿饲料质量、数量和成分的影响

外来一年生草类（包括水母草和北非草）的入侵极大地改变了美国西部的草原生态系统。人们不断努力通过使用一年生草选择性除草剂来恢复这些生态系统。这些除草剂的有效性和施用后植被的反应已有详细记录，但缺乏这些处理如何直接影响长尾鹿全年草料质量、数量和成分的研究。我们的目标是评估使用甲咪草烟（Open Range G，Wilbur-Ellis）改善夏季黑尾鹿饲料的功效，并评估该除草剂对冬季饲料可用性的潜在负面影响。 2020 年秋季，甲草烟被应用于 15 个 8 公顷的地块，这些地块位于美国俄勒冈州赫普纳周围草原栖息地的遥测黑尾鹿栖息地内。在 2021 年夏季和秋季以及 2022 年夏季，对配对处理地块和对照地块进行了为期两年的监测。我们的结果表明，甲马草烟的施用可用于提高饲料的营养质量，但可能会暂时减少第一阶段可用饲料的数量。治疗后夏季。第二个夏季，饲草生物量显着增加，但处理区内饲草的粗蛋白和可消化能含量不再占优势。甲草烟的施用对冬季牧草生物量或可用牧草的营养质量没有影响。甲马草处理似乎是提高夏季黑尾鹿草料质量和数量而不会对冬季食物来源产生不利影响的有效策略。