POSTFIRE RECRUITMENT OF 4 COOCCURRING BANKSIA SPECIES
POSTFIRE RECRUITMENT OF 4 COOCCURRING BANKSIA SPECIES
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DOI：
10.2307/2403899
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发表时间：
1987-08-01
影响因子：
5.7
通讯作者：
LAMONT, BB
中科院分区：
文献类型：
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作者：
COWLING, RM;LAMONT, BB
本文研究了秋、春两季烧伤后，影响扁枝木虱种群死亡率和存活率的因素。Br.，B。Leptophylla A.S.乔治，B。门齐耶西河Br.和B。prionotes林德利，在一个15岁的立场火灾易发灌木健康在澳大利亚西南部。记录了B从夏末到冬季从未燃烧的球果中释放的种子。menziesii（30%）和B.仅prionotes（3%）。两次烧伤后140天，除B外，所有物种95%以上的种子被释放。leptophylla在春季燃烧后的整个夏季保留17%的种子在球果中。从燃烧的球果种子释放的速度显着放缓后，所有物种的春天比秋季烧伤。秋季火烧后的扩散后种子捕食是可以忽略不计的，而它的范围从90%（B。prionotes）至98%（B.春天过后，燃烧。所有物种的种子在15 - 20 ℃下最佳发芽。C.秋烧后，围栏内田间发芽率为9%（B. menziesii）至69%（B. leptophylla）。更多的种子发芽的所有物种在未燃烧的比在秋季烧伤网站。春天燃烧后播种的种子在第二年夏天结束时没有发芽，它们的生存能力严重降低。大多数（54-97%）幼苗建立后，秋季烧伤已经死亡，主要是由于捕食，到夏末。捕食强度可能是不自然的高，由于小尺寸（c。2公顷）的资源丰富，秋烧补丁相对于邻近的大片未燃烧的灌木丛石南。显着减少幼苗内围栏后，秋季烧伤（32-52%）比在未燃烧的网站（71-80%）死亡，表明干旱诱导的死亡率在维持均匀年龄的人口在成熟的灌木丛生的重要性。到第一个冬天结束时，所有物种的每个亲本所招募的幼苗数量在秋季之后比春季燃烧之后高出两倍多。两次烧伤后2年以上，除B外，所有物种的幼苗更换水平均高于烧伤前的成虫密度。menziesii。在同一时期，未被烧毁的地区没有招募人员。为了维持班克西亚物种的数量，在冬季降雨开始之前，应该在秋季烧毁大片的灌木丛。财产保护和养护之间的冲突不能解决没有信息的火制度对灌木丛健康人群的影响。
The factors resonsible for genet mortality and survival after autumn and spring burns were studied for Banksia attenuata R. Br., B. leptophylla A.S. George, B. menziesii R. Br. and B. prionotes Lindley, in a 15-year-old stand of fire-prone scrub-health in south-western Australia. Late summer to winter seed release from unburnt cones was recorded for B. menziesii (30%) and B. prionotes (3%) only. One hundred and forty days after both burns, more than 95% of seeds of all species were released, except for B. leptophylla which retained 17% of seeds in cones throughout the summer after the spring burn. The rate of seed release from burnt cones was significantly slower for all species after the spring than the autumn burn. Post-dispersal seed predation after the autumn burn was negligible whereas it ranged from 90% (B. prionotes) to 98%(B. menziesii) after the spring burn. Seed of all species germinated optimally at 15-20.degree. C. After the autumn burn, field germination inside enclosures ranged from 9% (B. menziesii) to 69% (B. leptophylla). More seeds of all species germinated in the unburnt than in the autumn burn site. No seed sown after the spring burn had germinated by the end of the following summer and their viability was severely reduced. Most (54-97%) seedlings which established after the autumn burn had died, largely as a result of predation, by the end of the summer. Predation intensity was probably unnaturally high, due to the small size (c. 2 ha) of the resource-rich, autumn-burnt patch relative to the vast tracts of adjacent unburnt scrub-heath. Significantly fewer seedlings died inside enclosures after the autumn burn (32-52%) than in the unburnt site (71-80%), indicating the importance of drought-induced mortality in maintaining even-aged populations in mature scrub-heath. By the end of the first winter, the number of seedlings recruited per parent of all species was more than twice as high after the autumn than after the spring burn. More than 2 years after both burns, seedling replacement levels were higher than pre-burn adult densities for all species except B. menziesii. There was no recruitment in the unburnt area over the same period. In order to maintain the populations of the Banksia species, extensive tracts of scrub-heath should be burnt in autumn, prior to the onset of winter rain. Conflicts between property protection and conservation cannot be resolved without information on the fire-regime effects on scrub-heath populations.