|مجال التميز||تميز دراسي و بحثي|
|عنوان البحث:||Germination Assessment for Five Species of Acacia in Jibala, Saudi Arabia|
|رابط إلى البحث:||Click here|
|موجز عن البحث:||
Most Acacia species have a hard seed coat and therefore have become more resistant to unsuitable environmental conditions. The study aimed to assess the effects of different treatments on seed germination collected from five species of Acacia in Jibala, Al-Dawadmy, a city located in the Riyadh region of Saudi Arabia. The results showed that the highest germination percentage was 90.8%, with scarification treatment, while the lowest germination percentage was 30.9%, utilising a boiling treatment lasting seven minutes. Among the studied species, the seeds of A. ehrenbergiana produced the highest percentage of germination and the lowest germination time average among the studied species, while the lowest germination percentage and the highest germination time averages were found in A. nubica. Concluding, this study proved that scarification was the most effective technique for increasing germination rates, compared to other treatments.
|عنوان المؤتمر:||25th Biennial CERF Conference|
|تاريخ الإنعقاد:||3-7 November 2019|
|مكان الإنعقاد:||Mobile, Alabama, USA|
|طبيعة المشاركة:||Poster presentation|
|عنوان المشاركة:||Tidal elevations of UK saltmarshes: implications of the impacts of rising sea level|
Predicting the impacts of sea level rise on coastal landscapes requires a knowledge of their current morphology and the relationship between this and frequency of tidal inundation. We have examined the morphology of 35 UK saltmarshes using Light Detection and Ranging (Lidar) data. The majority have an extensive plateau lying at, or just below mean high water of spring tides (MHWS). In most cases, the marsh above this has a much steeper gradient, with halophytic vegetation growing on a pre-existing geomorphological surface (or a sea wall) and very limited sediment deposition. There are some exceptions to this. Where there have been recent sea level falls due to isostatic rebound, marine sediments now lie above MHWS. Where freshwater flow from land is great enough to allow a transition to freshwater marsh, deposition of peat continues to occur although in the UK, almost all these transitions have been truncated by extensive land reclamation.
This has several implications for the response of these marshes to sea level rise. In many cases, the upper marsh boundary can move only a very short distance inland; and the area of upland conversion will be limited. Coastal squeeze will occur even on unmodified coastlines. The presence of an extensive plateau indicates that a marsh is keeping pace with sea level rise, but to do so requires sufficient sediment supply to allow sediment deposition across the whole plateau at a rate equal to sea level rise. Increased dissection of a plateau by creeks indicates that the assimilative capacity of a marsh to respond to sea level rise may have been exceeded. Marsh platforms occur at around MHWS, but the water level during storm surges may be 2m or greater than this, so the extent to which saltmarshes will dissipate wave energy during storm surges has been overestimated.
BES Annual Meeting
|تاريخ الإنعقاد:||10 – 13 December 2019|
|مكان الإنعقاد:||Belfast, UK|
|طبيعة المشاركة:||Poster presentation|
|عنوان المشاركة:||Tidal elevations of UK saltmarshes: implications for ecosystem service delivery|
|ملخص المشاركة:||Textbook illustrations of saltmarshes usually picture an approximately uniform gradient from the pioneer zone to the upper tidal limit. But LIDAR data on 35 UK saltmarshes show that the majority have an extensive plateau lying at, or just below mean high water of spring tides (MHWS), with much steeper gradients above and below this. This pattern was described by geomorphologists several decades ago but is less well known in the ecological literature. It has significant implications for the ecosystem services provided by saltmarshes. Their elevation means that they will be submerged by 2 m or more of water during storm surges, limiting their effectiveness at dissipating wave energy. Sedimentation rates, and therefore carbon and nutrient burial, will be lower than on pioneer marshes. But soils will be relatively well oxygenated, so fluxes of the potent greenhouse gases methane and nitrous oxide may be lower than on the low marsh.|