کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4380626 1617696 2016 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Severe dry winter affects plant phenology and carbon balance of a cork oak woodland understorey
ترجمه فارسی عنوان
زمستان خشک شدید فنولوژی گیاه و تعادل کربن گیاهان زیر درختى جنگلی بلوط چوب پنبه را تحت تاثیر قرار می دهد
کلمات کلیدی
بوته؛ علفی؛ سوبر بلوط؛ تغییر آب و هوا خشکسالی زمستان؛ دریای مدیترانه
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک بوم شناسی، تکامل، رفتار و سامانه شناسی
چکیده انگلیسی


• We studied the effects of a severe dry winter on a cork oak woodland understorey.
• Plant phenology, seasonal water stress and carbon balance were assessed.
• Herbs were severely impacted contributing less than 10% to ecosystem assimilation.
• Shrubs were more resilient to the Mediterranean seasonal precipitation variability.
• Tree density and canopy cover influenced understorey contribution to ecosystem GPP.

Mediterranean climates are prone to a great variation in yearly precipitation. The effects on ecosystem will depend on the severity and timing of droughts. In this study we questioned how an extreme dry winter affects the carbon flux in the understorey of a cork oak woodland? What is the seasonal contribution of understorey vegetation to ecosystem productivity?We used closed-system portable chambers to measure CO2 exchange of the dominant shrub species (Cistus salviifolius, Cistus crispus and Ulex airensis), of the herbaceous layer and on bare soil in a cork oak woodland in central Portugal during the dry winter year of 2012. Shoot growth, leaf shedding, flower and fruit setting, above and belowground plant biomass were measured as well as seasonal leaf water potential. Eddy-covariance and micrometeorological data together with CO2 exchange measurements were used to access the understorey species contribution to ecosystem gross primary productivity (GPP).The herbaceous layer productivity was severely affected by the dry winter, with half of the yearly maximum aboveground biomass in comparison with the 6 years site average. The semi-deciduous and evergreen shrubs showed desynchronized phenophases and lagged carbon uptake maxima. Whereas shallow-root shrubs exhibited opportunistic characteristics in exploiting the understorey light and water resources, deep rooted shrubs showed better water status but considerably lower assimilation rates. The contribution of understorey vegetation to ecosystem GPP was lower during summer with 14% and maximum during late spring, concomitantly with the lowest tree productivity due to tree canopy renewal. The herbaceous vegetation contribution to ecosystem GPP never exceeded 6% during this dry year stressing its sensitivity to winter and spring precipitation.Although shrubs are more resilient to precipitation variability when compared with the herbaceous vegetation, the contribution of the understorey vegetation to ecosystem GPP can be quite variable and will ultimately depend of tree density and canopy cover.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Oecologica - Volume 76, October 2016, Pages 1–12
نویسندگان
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