کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4520420 1625157 2015 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Where do you draw the line? Determining the transition thresholds between estuarine salt marshes and terrestrial vegetation
ترجمه فارسی عنوان
خط را کجا رسم کردی؟ تعیین آستانه گذار بین نماتدهای نمک فاضلاب و پوشش گیاهی زمینی
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم زراعت و اصلاح نباتات
چکیده انگلیسی


• We found clear environmental correlates and thresholds for terrestrial vegetation but none for salt marsh vegetation.
• Terrestrial vegetation cover declined with increasing soil electrical conductivity
• Terrestrial vegetation cover declined with increasing groundwater electrical conductivity, and groundwater salinity and sediment moisture content
• This information will contribute to understanding of the boundary dynamics between these two vegetation types and the delineation of estuaries.

The aim of this study was to determine if abiotic thresholds are responsible for maintaining the salt marsh–terrestrial vegetation boundary. In eight estuaries along the South African coast, sediment and groundwater characteristics were measured in quadrats spanning the salt marsh, ecotone and terrestrial habitats. The cover of salt marsh vegetation showed no obvious limitation to any of the recorded environmental variables. This supports Purer's hypothesis that the upper boundary of estuaries is limited by competition. In contrast, terrestrial vegetation cover declined with increasing sediment electrical conductivity (threshold ~ 20–30 mS/cm), groundwater electrical conductivity (threshold ~ 60–80 mS/cm), and groundwater salinity (threshold ~ 20–40 ppt) and sediment moisture content (threshold ~ 20–25%). These variables were strongly correlated, and may be operating synergistically or a subset of these may be responsible for restricting terrestrial vegetation from occurring in the salt marsh. In the absence of landuse changes at the salt marsh–terrestrial boundary, salt marshes are unlikely to be unaffected by rising sea-levels as a landward migration will not be constrained by abiotic factors.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: South African Journal of Botany - Volume 101, November 2015, Pages 153–159
نویسندگان
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