Impacts of stressors on the emergence and growth of wetland plant species in Pennsylvania, USA

Mahaney, Wendy M.; Wardrop, Denice H.; Brooks, Robert

doi:10.1672/0277-5212(2004)024[0538:iosote]2.0.co;2

Cited by 19 publications

(14 citation statements)

References 29 publications

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“…Individual plant species responses to stressors are also likely to be influenced by the hydrologic and geomorphologic characteristics of different wetland classes (Mahaney et al, 2009). Also the toxic limits for nitrate in groundwater are likely to be much lower for some invertebrates than the drinking water limit, perhaps nearer to 2 mg L- …”

Section: Surface Water Wetlands and Groundwater-dependent Ecosystemsmentioning

confidence: 99%

A review of the impact of climate change on future nitrate concentrations in groundwater of the UK

Stuart

Gooddy

Bloomfield

et al. 2011

Science of The Total Environment

139

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This paper reviews the potential impacts of climate change on nitrate concentrations in groundwater of the UK using a Source-Pathway-Receptor framework. Changes in temperature, precipitation quantity and distribution, and atmospheric carbon dioxide concentrations will affect the agricultural nitrate source term through changes in both soil processes and agricultural productivity. Non-agricultural source terms, such as urban areas and atmospheric deposition, are also expected to be affected. The implications for the rate of nitrate leaching to groundwater as a result of these changes are not yet fully understood but predictions suggest that leaching rate may increase under future climate scenarios. Climate change will affect the hydrological cycle with changes to recharge, groundwater levels and resources and flow processes. These changes will impact on concentrations of nitrate in abstracted water and other receptors, such as surface water and groundwater-fed wetlands.The implications for nitrate leaching to groundwater as a result of climate changes are not yet well enough understood to be able to make useful predictions without more site-specific data.The few studies which address the whole cycle show likely changes in nitrate leaching ranging from limited increases to a possible doubling of aquifer concentrations by 2100.These changes may be masked by nitrate reductions from improved agricultural practices, but a range of adaption measures need to be identified. Future impact may also be driven by economic responses to climate change. The study draws on extensive literature mainly from the UK and so presents a UK-based perspective, although literature for other temperate climates is included to augment that from Keywordsthe UK and to demonstrate that the proposed framework and general conclusions have a wider applicability.The principal N input to UK groundwater is derived from manures, fertilisers, sewage sludges and crop residues in agricultural areas (DEFRA, 2006). There are also smaller inputs from urban point sources and aerial deposition (Wakida and Lerner, 2005). N fertiliser can be applied as urea or ammonia, as well as nitrate, but the non-nitrate forms are generally converted rapidly to nitrate in the soils of the UK (MAFF, 1999). A small percentage of applied N is lost to the atmosphere as NH 3 , NO or N 2 O (Destouni and Darracq, 2009;Skiba et al., 1997;Sommer and Hutchings, 1995). A proportion of soil N is leached as nitrate from the base of the soil. This is either stored in, or transmitted through, the unsaturated zone to groundwater. groundwater. They found that although an ensemble average suggests there will be about a 5% reduction in annual potential groundwater recharge across the study area, this was not statistically significant at the 95% confidence level and more importantly observed that the spread of results for simulated changes in annual potential groundwater recharge range from a 26% decrease to a 31% increase by the 2080s, with ten GCMs predicting a decrease and three a...

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Section: Surface Water Wetlands and Groundwater-dependent Ecosystemsmentioning

confidence: 99%

A review of the impact of climate change on future nitrate concentrations in groundwater of the UK

Stuart

Gooddy

Bloomfield

et al. 2011

Science of The Total Environment

139

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“…Several studies have found a one-time application of 0.5-1.0 cm of sediment can reduce seedling emergence in small-seeded species (Gleason et al 2003;Jurik et al 1994;Mahaney et al 2004;Peterson and Baldwin 2004). For larger seeds, a threshold appears to exist around 2 cm (Barry et al 2004;Bonis and Lepart 1994;Welling and Becker 1990;Zheng et al 2005).…”

Section: Seed Sizementioning

confidence: 99%

“…However, sedimentation creates a very smooth soil surface, filling in and eliminating microrelief (Werner and Zedler 2002). Studies of seed burial suggest that even small amounts of sediment may reduce emergence of small seeds (Barry et al 2004;Bonis and Lepart 1994;Gleason et al 2003;Jurik et al 1994;Mahaney et al 2004;Peterson and Baldwin 2004;Petru and Menges 2004;Welling and Becker 1990), indicating that sedimentation may favor large-seeded species over those with small seeds. Sediment texture may also play a role in germination, though this may vary by species.…”

Section: Introductionmentioning

confidence: 99%

Changes in riparian forest composition along a sedimentation rate gradient

2010

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Riparian forests are highly valued for maintaining water quality through the retention of sediments and nutrients. They also provide some of the most diverse and species-rich habitats in the world. What is largely unknown, however, is how sediment deposition affects plant community composition in these forests. The objective of this study was to examine changes in plant community composition across a gradient of increasing rates of sedimentation in riparian forests in the southeastern Coastal Plain, USA. Seventeen plots were established within riparian forests receiving between 0 and 5.5 cm year -1 of sediment deposits. Species density and biomass estimates were collected annually from 2002 to 2006 for overstory and mid-story plant species within each plot. Percent cover and nested frequency of understory plant species were determined annually during 2004-2006. Measures of community composition in the understory, mid-story, and overstory layers of forests were compared to changes in environmental factors associated with increased sedimentation. In the understory, annual, exotic, and upland species had higher importance values in plots receiving high sediment deposition. The densities of shade-intolerant and N-fixing species in the mid-story also increased with increasing sedimentation rates. Increased overstory mortality was associated with high sedimentation rates, though increases in understory light levels in these gaps were not the main driver of understory species changes. Edaphic factors, such as soil texture, moisture, and temperature, were significantly correlated to species composition in all three forest layers, suggesting that changes in soil physical structure due to sedimentation may drive community-level changes in these forests.

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“…Because much of the world's population is situated close to coasts and waterways, the dramatic increases in urbanisation have produced concomitant decreases in the area of wetlands (Harty 2004;Wang et al 2005). Even intact wetlands suffer a variety of impacts from urbanisation including increased loads of nutrients and pollutants (Kerry et al 2004;Mallin et al 2004;McPherson et al 2005), and increased eutrophication (Mahaney et al 2004;Taylor et al 2004) and sedimentation (Lohrer et al 2004;Mahaney et al 2004). In turn these lead to a range of detrimental ecological effects including reduced species richness, modified faunal assemblages (Argent and Carline 2004) and reductions in the number of 'sensitive' species (Gray 2004).…”

Section: Introductionmentioning

confidence: 99%

“…In turn these lead to a range of detrimental ecological effects including reduced species richness, modified faunal assemblages (Argent and Carline 2004) and reductions in the number of 'sensitive' species (Gray 2004). Influences on plant communities are particularly wide-spread (Mahaney et al 2004), and include reduced native vegetation cover (Alberti et al 2004), compromised health and growth of aquatic plants (Balestri et al 2004) and reductions in shoreline plant diversity (Elias and Meyer 2003).…”

Section: Introductionmentioning

confidence: 99%