Davies K W, Bates J D, Madsen M D, Nafus A M
USDA - Agricultural Research Service, 67826-A Hwy 205, Burns, OR, 97720, USA,
Environ Manage. 2014 May;53(5):1015-22. doi: 10.1007/s00267-014-0255-5. Epub 2014 Feb 27.
Western juniper (Juniperus occidentalis ssp. occidentalis Hook) encroachment into mountain big sagebrush (Artemisia tridentata spp. vaseyana (Rydb.) Beetle) steppe has reduced livestock forage production, increased erosion risk, and degraded sagebrush-associated wildlife habitat. Western juniper has been successfully controlled with partial cutting followed by prescribed burning the next fall, but the herbaceous understory and sagebrush may be slow to recover. We evaluated the effectiveness of seeding perennial herbaceous vegetation and sagebrush at five sites where juniper was controlled by partially cutting and prescribed burning. Treatments tested at each site included an unseeded control, herbaceous seed mix (aerially seeded), and the herbaceous seed mix plus sagebrush seed. In the third year post-treatment, perennial grass cover and density were twice as high in plots receiving the herbaceous seed mix compared to the control plots. Sagebrush cover and density in the sagebrush seeded plots were between 74- and 290-fold and 62- and 155-fold greater than the other treatments. By the third year after treatment, sagebrush cover was as high as 12 % in the sagebrush seeded plots and between 0 % and 0.4 % where it was not seeded. These results indicate that aerial seeding perennial herbaceous vegetation can accelerate the recovery of perennial grasses which likely stabilize the site. Our results also suggest that seeding mountain big sagebrush after prescribed burning encroaching juniper can rapidly recover sagebrush cover and density. In areas where sagebrush habitat is limited, seeding sagebrush after juniper control may increase sagebrush habitat and decrease the risks to sagebrush-associated species.
西部刺柏（Juniperus occidentalis ssp. occidentalis Hook）侵入山地大艾草（Artemisia tridentata spp. vaseyana (Rydb.) Beetle）草原，降低了牲畜饲料产量，增加了侵蚀风险，并破坏了与艾草相关的野生动物栖息地。通过部分砍伐并在次年秋季进行规定火烧，西部刺柏已得到成功控制，但草本下层植被和艾草的恢复可能较慢。我们评估了在五个通过部分砍伐和规定火烧控制刺柏的地点播种多年生草本植被和艾草的效果。每个地点测试的处理包括未播种对照、草本种子混合物（空中播种）以及草本种子混合物加艾草种子。在处理后的第三年，与对照地块相比，接受草本种子混合物的地块多年生草的覆盖度和密度高出两倍。播种艾草地块的艾草覆盖度和密度比其他处理高出74至290倍以及62至155倍。到处理后的第三年，播种艾草地块的艾草覆盖度高达12%，未播种的地块则在0%至0.4%之间。这些结果表明，空中播种多年生草本植被可以加速多年生草的恢复，这可能会稳定该地点。我们的结果还表明，在规定火烧入侵的刺柏后播种山地大艾草可以迅速恢复艾草的覆盖度和密度。在艾草栖息地有限的地区，在控制刺柏后播种艾草可能会增加艾草栖息地，并降低对与艾草相关物种的风险。
