دورية أكاديمية
Shifts in litterfall and dominant nitrogen sources after expansion of shrub thickets.
| العنوان: | Shifts in litterfall and dominant nitrogen sources after expansion of shrub thickets. |
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| المؤلفون: | Brantley ST; Department of Biology, Virginia Commonwealth University, Richmond, VA 23284, USA., Young DR |
| المصدر: | Oecologia [Oecologia] 2008 Mar; Vol. 155 (2), pp. 337-45. Date of Electronic Publication: 2007 Nov 27. |
| نوع المنشور: | Journal Article; Research Support, U.S. Gov't, Non-P.H.S. |
| اللغة: | English |
| بيانات الدورية: | Publisher: Springer Country of Publication: Germany NLM ID: 0150372 Publication Model: Print-Electronic Cited Medium: Print ISSN: 0029-8549 (Print) Linking ISSN: 00298549 NLM ISO Abbreviation: Oecologia Subsets: MEDLINE |
| أسماء مطبوعة: | Original Publication: Berlin ; New York, Springer. |
| مواضيع طبية MeSH: | Ecosystem*, Carbon/*analysis , Myricaceae/*chemistry , Nitrogen/*analysis , Soil/*analysis, Actinobacteria/metabolism ; Nitrogen Fixation/physiology ; Nitrogen Isotopes/analysis ; Plant Leaves/chemistry ; Poaceae/chemistry ; Seasons ; Virginia |
| مستخلص: | Woody encroachment into herbaceous ecosystems is emerging as an important ecological response to global change. A primary concern is alterations in C and N cycling and associated variations across a variety of ecosystems. We quantified seasonal variation in litterfall and litter N concentration in Morella cerifera shrub thickets to assess changes in litterfall and associated N input after shrub expansion on an Atlantic coast barrier island. We also used the natural abundance of (15)N to estimate the proportion of litterfall N originating from symbiotic N fixation. Litterfall for shrub thickets ranged from 8,991 +/- 247 to 3,810 +/- 399 kg ha(-1) year(-1) and generally declined with increasing thicket age. Litterfall in three of the four thickets exceeded previous estimates of aboveground annual net primary production in adjacent grasslands by 300-400%. Leaf N concentration was also higher after shrub expansion and, coupled with low N resorption efficiency and high litterfall, resulted in a return of as much as 169 kg N ha(-1) year(-1) to the soil. We estimated that approximately 70% of N returned to the soil was from symbiotic N fixation resulting in an ecosystem input of between 37 and 118 kg ha(-1) year(-1) of atmospheric N depending on site. Considering the extensive cover of shrub thickets on Virginia barrier islands, N fixation by shrubs is likely the largest single source of N to the system. The shift from grassland to shrub thicket on barrier islands results in a substantial increase in litterfall and foliar N concentration that will likely have a major impact on the size and cycling of ecosystem C and N pools. Increasing C and N availability in these nutrient-poor soils is likely to permanently reduce cover of native grasses and alter community structure by favoring species with greater N requirements. |
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| المشرفين على المادة: | 0 (Nitrogen Isotopes) 0 (Soil) 7440-44-0 (Carbon) N762921K75 (Nitrogen) |
| تواريخ الأحداث: | Date Created: 20071128 Date Completed: 20080603 Latest Revision: 20211020 |
| رمز التحديث: | 20221213 |
| DOI: | 10.1007/s00442-007-0916-7 |
| PMID: | 18040723 |
| قاعدة البيانات: | MEDLINE |
Find this article in full text from Springer Verlag. 
Full Text Finder | تدمد: | 0029-8549 |
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| DOI: | 10.1007/s00442-007-0916-7 |