Vegetation and soil within estuarine ecosystems play an integral role in ecological processes within pocket estuaries. However, physical barriers, caused by culverts diminish hydrological inputs, sediment exchange, an...Vegetation and soil within estuarine ecosystems play an integral role in ecological processes within pocket estuaries. However, physical barriers, caused by culverts diminish hydrological inputs, sediment exchange, and habitat connectivity. The restoration of estuaries by bridge replacement reconnects <span>the aquatic corridor, however, the recovery of plant communities and soil s</span>ubstrate is not well understood. This observational study monitored four estuary restoration sites of variable ages (0 - 12 years) in Western Washington, USA. Plant community composition, soil organic carbon, organic matter, and soil nutrients were assessed. Percent soil carbon was different among the pre-restoration and youngest (3-year) post-restoration site (<i>P</i> = 0.03), suggesting an initial decrease in carbon and organic matter during restoration. Both N and P were deficient at the newest, lower restoration site, presumably linked to the lack of organic matter required for adequate cation exchange capacity and nutrient/plant exchange (<i>P</i> < 0.05). Plant species diversity was higher at the intermediate (9-year) and oldest post-restoration sites (12-year;<i>P</i> = 0.02). Vegetation composition was primarily native species with few invasive plants present. The results of this study illustrate that tidal marsh plant communities are influenced by the development of salinity and vertical gradients with older sites having an increase in species diversity. Future surveys are ongoing to <span>better understand how these sites recover organic matter and tidal marsh co</span>mmunities to form adequate estuarine habitat over time.展开更多
Background:Habitat degradation is known to have a major impact on the composition of bird communities,yet how these communities recover following such disturbance is less understood.This study examined bird community ...Background:Habitat degradation is known to have a major impact on the composition of bird communities,yet how these communities recover following such disturbance is less understood.This study examined bird community changes from pre-logging to recovery over the course of habitat disturbance caused by the development of the Hulu Terengganu Hydroelectric Dam Project in Peninsular Malaysia,between 2007 and 2018.Bird surveys were conducted using point count observations and mist netting in the dam area from the prelogging phase until the operation phase.Results:It was observed that while bird species significantly declined after large-scale habitat clearance between the pre-logging and construction phases,they showed positive signs of recovery from the inundation to operation phases.These findings indicate that the bird community is still recovering,and the permanent loss of habitat required by most of the original species has not occurred,as evidenced by recolonisation.Bird species composition differed across phases due to varying habitat conditions.The turnover rate and immigration rate(recolonisation and newly recorded species)were higher between the construction and operation phases.It was also observed that insectivorous birds were more heavily affected than others by changes to the landscape,which highlights the versatility,survivability and tolerance of certain species to extreme disturbance and habitat modification.Conclusion:Although the operation phase showed an incremental change in bird species richness due to recolonisation and newly recorded species,this value remains far from that of the pre-logging phase.We predict that bird species recovery will continue to increase for some time before reaching a plateau among the newly created islands,reservoir and catchment area of the dam.展开更多
文摘Vegetation and soil within estuarine ecosystems play an integral role in ecological processes within pocket estuaries. However, physical barriers, caused by culverts diminish hydrological inputs, sediment exchange, and habitat connectivity. The restoration of estuaries by bridge replacement reconnects <span>the aquatic corridor, however, the recovery of plant communities and soil s</span>ubstrate is not well understood. This observational study monitored four estuary restoration sites of variable ages (0 - 12 years) in Western Washington, USA. Plant community composition, soil organic carbon, organic matter, and soil nutrients were assessed. Percent soil carbon was different among the pre-restoration and youngest (3-year) post-restoration site (<i>P</i> = 0.03), suggesting an initial decrease in carbon and organic matter during restoration. Both N and P were deficient at the newest, lower restoration site, presumably linked to the lack of organic matter required for adequate cation exchange capacity and nutrient/plant exchange (<i>P</i> < 0.05). Plant species diversity was higher at the intermediate (9-year) and oldest post-restoration sites (12-year;<i>P</i> = 0.02). Vegetation composition was primarily native species with few invasive plants present. The results of this study illustrate that tidal marsh plant communities are influenced by the development of salinity and vertical gradients with older sites having an increase in species diversity. Future surveys are ongoing to <span>better understand how these sites recover organic matter and tidal marsh co</span>mmunities to form adequate estuarine habitat over time.
基金funded by Tenaga Nasional Berhad Research(TNBR),grant number ST-2017-010.
文摘Background:Habitat degradation is known to have a major impact on the composition of bird communities,yet how these communities recover following such disturbance is less understood.This study examined bird community changes from pre-logging to recovery over the course of habitat disturbance caused by the development of the Hulu Terengganu Hydroelectric Dam Project in Peninsular Malaysia,between 2007 and 2018.Bird surveys were conducted using point count observations and mist netting in the dam area from the prelogging phase until the operation phase.Results:It was observed that while bird species significantly declined after large-scale habitat clearance between the pre-logging and construction phases,they showed positive signs of recovery from the inundation to operation phases.These findings indicate that the bird community is still recovering,and the permanent loss of habitat required by most of the original species has not occurred,as evidenced by recolonisation.Bird species composition differed across phases due to varying habitat conditions.The turnover rate and immigration rate(recolonisation and newly recorded species)were higher between the construction and operation phases.It was also observed that insectivorous birds were more heavily affected than others by changes to the landscape,which highlights the versatility,survivability and tolerance of certain species to extreme disturbance and habitat modification.Conclusion:Although the operation phase showed an incremental change in bird species richness due to recolonisation and newly recorded species,this value remains far from that of the pre-logging phase.We predict that bird species recovery will continue to increase for some time before reaching a plateau among the newly created islands,reservoir and catchment area of the dam.
