Alleviation of summer drought boosts establishment success of Pinus sylvestris in a Mediterranean mountain:: an experimental approach
Alleviation of summer drought boosts establishment success of Pinus sylvestris in a Mediterranean mountain:: an experimental approach
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DOI：
10.1007/s11258-005-6626-5
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发表时间：
2005-12-01
期刊：
影响因子：
1.7
通讯作者：
Gómez, JM
中科院分区：
文献类型：
--
作者：
Castro, J;Zamora, R;Gómez, JM
在樟子松分布区最南端进行了灌溉试验，研究夏季干旱对樟子松林分建立的影响。浇水是在第一个生长季节模拟中夏季条件下进行的，我们监测了第一个生长季节的生存和生长的后果和第二个生长季节的延迟后果。此外，我们考虑了由微生境，种子被发现后分散（裸土，灌木下，成年松树下）创建的异质性。夏季干旱是所有小生境的主要死亡因子。浇水增加了出苗率，幼苗存活率比不浇水的对照点增加了一倍。当考虑到对出苗和存活的累积效应时，差异甚至更高，浇灌地块的总体招募率为22.4%，对照为7.9%。灌溉增加了裸土和灌木下的生长，但对松树下的生长影响不大，这表明辐射是这个微生境的限制因素。灌溉对生长参数的积极影响持续在第二个生长季节，尽管水没有增加的第二年，表现出延迟的后果干旱对幼苗的性能。因此，夏季干旱限制了樟子松建立在这些最南端的森林，减少招聘和增长。这可能会导致发展的残余动态在这些孑遗种群在目前的区域增加与全球变暖相关的干旱和降雨量的变化。
We performed an irrigation experiment to study the impact of summer drought on Pinus sylvestris establishment at its southernmost distribution limit. Watering was done during the first growing season simulating mesic summer conditions, and we monitored the consequences for survival and growth during the first growing season and the delayed consequences on the second growing season. In addition, we considered the heterogeneity created by the microhabitats, where seeds are found after dispersal (bare soil, under shrubs, and under adult pines). Summer drought was the main mortality factor in all the microhabitats. Watering increased emergence and doubled seedling survival compared to non-watered control sites. Differences were even higher when the cumulative effect on emergence and survival was considered, with an overall recruitment of 22.4% in watered plots vs. 7.9% in control. Irrigation increased growth in bare soil and under shrubs, but had scant effect on growth under pines, suggesting that radiation was the limiting factor in this microhabitat. The positive effect of irrigation on growth parameters persisted during the second growing season despite water was not added the second year, showing delayed consequences of drought on seedling performance. Summer drought thus limits Pinus sylvestris establishment in these southernmost forests by reducing both recruitment and growth. This might lead to the development of a remnant dynamic in these relict populations under the current regional increase in dryness and rainfall variability associated with global warming.