Gregg E. Moore

Belowground biomass of Phragmites australis in coastal marshes.

Abstract The distribution of below ground biomass within monotypic stands of invasive Phragmites australis (Common Reed) was documented from a series of oligo-, meso-, and polyhaline coastal marshes in New Hampshire. Soil profiles were described, and live biomass was documented growing to a maximum depth of 95 cm for roots and 85 cm for rhizomes. Our data show that invasive P. australis utilizes a greater depth range than native graminoids (90% within the top 70 cm and top 20 cm, respectively). We corroborate prior anecdotal observations and provide further evidence illustrating the potential for this invasive plant to access resources (i.e., water and nutrients) at depths greater than the native species with which it competes.

A Floristic Comparison of Seaweeds from James Bay and Three Contiguous Northeastern Canadian Arctic Sites

Abstract The seaweed flora from James Bay, Canada is compared with three contiguous northeastern Canadian Arctic areas (Hudson Bay, Hudson Strait, and the Ellesmere-Baffin Islands area extending northward to the Arctic Ocean). A conspicuous reduction pattern was evident with 131 taxa recorded for the Ellesmere-Baffin Islands area, 106 for Hudson Strait, 81 from Hudson Bay, and 44 in James Bay. The Ellesmere-Baffin Islands area has a more rocky open coastal environment and higher salinities than James Bay, which is more highly sedimented and impacted by hydroelectric development and freshwater discharge. The Ellesmere-Baffin Islands area (∼32–30.5‰) has a higher mean number of shared taxa (90.0 ± 18.4 SE) than James Bay (37.6 ± 2.7 SE), while Hudson Strait and Hudson Bay have intermediate values of 78 ± 14.1 SE and 64 ± 9.2 SE, respectively. The combined flora from the four areas consists of 164 taxa, including 49 red, 65 brown, 1 chrysophyte, and 49 green algae. Fifty of these total taxa (31%) were only found in one area, with 25 occurring between Ellesmere Island and Baffin Island, 13 within the Strait proper, and 6 in both Hudson and James Bays. Strong habitat and salinity gradients, as well as the great distances between collection sites and the haphazard nature of collections may have contributed to these restrictive patterns. Cheneys (1977) floristic ratio documents that all four geographies (including their composite flora) have cold water floras. Four new distributional records are documented from James Bay: Chaetomorpha minima, Elachista fucicola, Phyllophora pseudoceranoides, and Spyridia filamentosa. The cryptogenic taxon Spyridia, which has unclear origins, is a warm-water disjunct in the northwestern Atlantic previously known only from one site in Nova Scotia and a few locations in southern Maine/New Hampshire but mostly south of Cape Cod, Massachusetts. A single introduced species (Dumontia contorta from Europe) is recorded from James Bay and the Ellesmere-Baffin Islands area, while none are documented from the other areas.

Recovering Salt Marsh Ecosystem Services through Tidal Restoration

Some would maintain that conservation and restoration activities are justified on ethical grounds alone (see review by Brennan and Lo 2008). However, demonstration of the economic benefit of ecosystems can help drive social and governmental support for conservation; and restoration and economic limitations could force choices among restoration activities. To aid decision making we need to estimate the values that restored ecosystems will provide for society. But defining these values remains a significant challenge, particularly within the context of restoration in which functions have been impaired and may contribute only incremental services over the varying course of the restoration process. Nonetheless, wetlands have direct and indirect economic value to local communities, and they provide services that benefit society as a whole. The term “ecosystem services” encompasses benefits that have direct economic value and those that have indirect public benefits. Evaluating and quantifying ecosystem services is a challenge regardless of the system status: natural, disturbed, or in various stages of restoration.

Mapping soil pore water salinity of tidal marsh habitats using electromagnetic induction in Great Bay Estuary, USA.

Electromagnetic induction was used to measure apparent conductivity of soil pore water within 15 oligohaline to polyhaline tidal marshes of the Great Bay Estuary in New Hampshire, USA. The instrument was linked to a differential global positioning system via a hand-held field computer to geo-reference data. Apparent conductivity was converted to salinity using a regression derived from field data, and mapped to illustrate spatial salinity gradients throughout the marshes. Plant communities occurring at the study sites included native low marsh, high marsh, and brackish tidal riverbank marsh, as well as communities dominated by native and non-native common reed, Phragmites australis. Results revealed mean salinity values were significantly different between each of the community categories sampled within the Estuary. Due to management concerns over expansion of Phragmites within the Estuary, we mapped the salinity range for this community and provided graphic and numerical estimates of potential Phragmites habitat based on salinity alone (26% of the total acreage surveyed). Electromagnetic induction is an efficient tool for rapid reconnaissance of apparent conductivity and salinity gradients in tidal marsh soils that can be superimposed on aerial imagery to estimate suitable habitat for restoration or invasive control based on salinity ranges.

Distribution of Mangrove Habitats of Grenada and the Grenadines

ABSTRACT Moore, G.E.; Gilmer, B.F., and Schill, S.R., 2015. Distribution of mangrove habitats of Grenada and the Grenadines. Mangroves of Grenada and the Grenadines represent significant habitat within the regional context of the Eastern Caribbean. Losses of mangroves through storms, development, and climate change have negative impacts on critical ecosystem services. Estimates of mangrove area exist in the literature but do not fully reflect current conditions, effects of disturbance, and results of recovery; they also do not differentiate these areas by community types. Advances in imagery and remote sensing approaches allow higher-resolution resource mapping. We used remote sensing, image interpretation, and field verification techniques to provide current estimates of the extent and distribution of mangroves. Our results provide the greatest areal total of mangroves to date. Despite loss of mangroves in the recent past, we accounted for approximately 15% more hectares than estimated in the 1990s and 28% more than predicted by hypothetical models for 2005. The discrepancies between prior and current mapped areas are likely due to differences in mapping precision and incomplete surveys that omitted the smaller Grenadine islands but also reflect actual increases in cover from natural recovery and recruitment following historic storm events. Basin mangroves represented the greatest area, while riverine and scrub contributed the least. Fringe mangroves were moderately abundant but were composed of small, isolated patches with high vulnerability to coastal storms and limited opportunity for inland retreat. Documenting the presence and distribution of mangroves, and specifically mangrove community types, will be of value to conservation, restoration, and management planning in light of predicted sea level rise and climate change effects.

Distribution, Pore-Water Chemistry, and Stand Characteristics of the Mangroves of the United Arab Emirates

ABSTRACT Moore, G.E.; Grizzle, R.E.; Ward, K.M., and Alshihi, R.M., 2015. Distribution, pore-water chemistry, and stand characteristics of the mangroves of the United Arab Emirates. Mangroves are the dominant coastal vegetation of the United Arab Emirates (UAE), occupying one of the driest mangrove habitats in the world. However, published estimates of mangroves do not represent current conditions for the country as a whole. This study provides an up-to-date estimate of UAEs mangroves, summarizing their habitat characteristics, stand heights, and pore-water conditions. Estimates of mangrove cover are based upon remote sensing, aerial photointerpretation, and field verification. Our results document more mangroves than previously estimated for Abu Dhabi and the nation altogether. Mapped areas were classified into three descriptive density cover classes to facilitate interpretation of the data: low (<10%), moderate (10–75%), and high (>75%). The high-density class reflects prior national estimates for mangrove coverage (roughly 3613 ha), while moderate- and low-density classes contributed an additional 5659 ha and 4344 ha (respectively) to the national total. The largest contiguous mangrove area was 710 ha, while the smallest mapped area was 0.03 ha. Mapped mangrove habitat types included fringe, basin, and overwash, with average heights of 3.36 ± 0.25 m and density of 61.83% ± 5.01%. Stand height and pore-water sulfide concentrations were significantly different between habitat types, while stand density, pore-water salinity, and redox potential were highly variable. In sum, approximately 13,616 ha of mangrove area was mapped, roughly three times more than prior estimates. This is the first study in recent years to document the full areal extent of mangroves and associated stand characteristics across the seven emirates.

Evaluating Tidal Wetland Restoration Performance Using National Estuarine Research Reserve System Reference Sites and the Restoration Performance Index (RPI)

Evaluations of tidal wetland restoration efforts suffer from a lack of appropriate reference sites and standardized methods among projects. To help address these issues, the National Estuarine Research Reserve System (NERRS) and the NOAA Restoration Center engaged in a partnership to monitor ecological responses and evaluate 17 tidal wetland restoration projects associated with five reserves. The goals of this study were to (1) determine the level of restoration achieved at each project using the restoration performance index (RPI), which compares change in parameters over time between reference and restoration sites, (2) compare hydrologic and excavation restoration projects using the RPI, (3) identify key indicator parameters for assessing restoration effectiveness, and (4) evaluate the value of the NERRS as reference sites for local restoration projects. We found that the RPI, modified for this study, was an effective tool for evaluating relative differences in restoration performance; most projects achieved an intermediate level of restoration from 2008 to 2010, and two sites became very similar to their paired reference sites, indicating that the restoration efforts were highly effective. There were no differences in RPI scores between hydrologic and excavation restoration project types. Two abiotic parameters (marsh platform elevation and groundwater level) were significantly correlated with vegetation community structure and thus can potentially influence restoration performance. Our results highlight the value of the NERRS as reference sites for assessing tidal wetland restoration projects and provide improved guidance for scientists and restoration practitioners by highlighting the RPI as a trajectory analysis tool and identifying key monitoring parameters.

A globally rare coastal salt pond marsh system at Odiorne Point State Park, Rye, New Hampshire.

Abstract Vegetation patterns in the coastal salt pond marsh system at Odiorne Point State Park in Rye, New Hampshire, the states only viable example, are described based on recent surveys and historical data. Four natural communities occur within the system: coastal salt pond flat, coastal salt pond emergent marsh, coastal salt pond meadow marsh, and highbush blueberry–winterberry shrub thicket. The first three communities are newly described in New Hampshire and the northeastern US coastline. A total of 69 native or naturalized vascular plant taxa from 54 genera and 33 families have been documented in the system at Odiorne Point between 1967 and 2011. The families best represented were Cyperaceae (10 taxa), Poaceae (9 taxa), and Asteraceae (6 taxa); the largest genera were Eleocharis (4 taxa), Hypericum (4 taxa), and Agrostis (3 taxa). In 2011, only 35 of the 69 plant taxa were documented; a difference that can be attributed, at least partially, to the variable nature of hydrologic and salinity influences on the system. Of the 69 plant taxa, three are rare in New Hampshire and five are both non-native and invasive in the state and region. The uncertainty of the nativity status of Typha angustifolia, the dominant species in the marsh, has significant implications for future management decisions. Measurement of surface and pore water salinity in late summer of 2011 revealed essentially fresh water conditions at the surface (1.1 ± 0.5 ppt SE), whereas pore water occurring 10 cm and 40 cm below the soil surface was mesohaline (5.8 ± 1.8 and 8.1 ± 1.8 ppt SE, respectively). Mean pore water salinity differed significantly among the natural communities examined, suggesting that hydrology and salinity influence species composition and distribution within coastal salt pond marsh systems. This globally rare system, distributed from Maine to New Jersey, shares similar dominant species across its range, although some of the state rare species it supports differ along a latitudinal gradient.

Status of the Eastern Grasswort, Lilaeopsis chinensis (Apiaceae), in the Great Bay Estuary, New Hampshire, U.S.A

Abstract A survey of oligohaline and mesohaline tidal marshes along the upper reaches of eight tidal rivers in the Great Bay Estuary of New Hampshire was conducted to document the occurrence of eastern grasswort, Lilaeopsis chinensis, a state-listed, rare species. Historical sites were visited to assess the presence, absence, or significant population changes of this rare coastal species. We re-located four of five historically documented element occurrences, noted the plants potential expansion on several rivers and a decline at three other sites, and identified a new occurrence on a river system with no prior documented accounts. The results suggest that overall, L. chinensis has been relatively stable for the last 60 years, although the loss of plants at three of the sites suggests it is threatened by continued development (dams and tidal restrictions) and associated impacts to water quality.