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Anthropogenic climate and non-climate drivers of change are causing significant impacts on estuarine and coastal marine environments. Climate change poses a particular threat to the structure and function of biotic communities in these environments because it acts on the most extensive temporal and spatial scales relative to other anthropogenic drivers of change. The interaction of multiple environmental drivers exacerbates degradation of ecosystem condition. Estuaries are most susceptible to climate-change mediated biotic shifts and direct anthropogenic impacts due to burgeoning human population growth and development in coastal watersheds. Multiple anthropogenic drivers of change, which often interact synergistically, alter physical, chemical, and biological characteristics. Ecological responses may be increasingly nonlinear, with cumulative effects manifested by marked changes in organism abundance, distribution, diversity, and productivity. Detrimental biotic effects in impacted coastal environments cascade up from individual organisms to population and community levels, culminating in ecosystem-level changes including reduced services. Multiple drivers of change and their impacts are increasing in estuarine and coastal marine environments with greater anthropogenic forcing in the coastal zone and global effects of climate change, creating greater challenges for environmental management and conservation programs.

The National Estuarine Research Reserve System (NERRS) is an integrated network of 29 protected and coordinated estuarine reserve sites in 23 states and one territory (Puerto Rico) covering more than 525,000 ha of estuarine habitat, adjoining wetlands, and uplands that encompass 19 biogeographical regions along the Atlantic, Gulf of Mexico, and Pacific coasts, as well as the Caribbean Sea and Great Lakes. NERRS is an ecosystem-based research and monitoring network of sites serving as platforms to develop quantitative databases of value to coastal management programs in identifying and tracking short-term variability and long-term changes in the integrity and biodiversity of estuarine systems nationwide due to natural perturbations and anthropogenic disturbances. The reserve sites also play a vital role in assessing coastal issues of local, regional, and national significance for the purpose of sustaining estuarine systems and coastal lands, such as evaluating their responses to climate change and other major stressors to inform coastal decision-making and public awareness for the protection and resilience of natural resources and coastal communities. Over the past four decades, NERRS sites have collected large volumes of research and monitoring data of great utility in characterizing estuarine environments and addressing an array of resource-management concerns, including degraded water quality, loss and alteration of essential habitat, impacted fisheries, invasive species, and conservation.

Salt marsh ecosystems provide many critical ecological functions, yet they are subject to considerable disturbance ranging from direct human alteration to increased inundation due to climate change. We assessed emergent salt marsh plant characteristics in the Tuckerton Peninsula, a large expanse (~2,000 ha) of highly inundated habitat along the southern New Jersey coast, USA. Key salt marsh plant parameters were monitored in the heavily grid-ditched northern segment, Open Marsh Water Management (OMWM) altered central segment, and the shoreline altered southern segment of the peninsula in the summer months of 2011 and 2013. Plant species composition and three metrics of abundance and structure (maximum canopy height, percent areal cover, and shoot density) were examined among marsh segments, along transects within segments, seasonally by month, and between years. Despite seasonal or annual variability, the northern segment of the marsh differed in plant species composition from the central and southern segments. This difference was partly due to greater percent areal cover in the northern segment of such upper marsh species as Spartina patens and Distichlis spicata. S. patens also exhibited higher shoot densities in the northern segment than the central segment. Despite the higher abundance of upper marsh species, marsh surface elevations were lower in the northern segment than in the central or southern segments, suggesting the influence of altered hydrology due to human activities. Understanding current variation in the emergent salt marsh vegetation along the peninsula will help inform future habitat change in other coastal wetlands of New Jersey and the mid-Atlantic region subject to natural and anthropogenic drivers.

Spatial and temporal characteristics of Zostera marina (eelgrass) in the Barnegat Bay-Little Egg Harbor Estuary are compared before (2004-2011) and after (2012-2013) major fertilizer legislation (Fertilizer Law A2290) was enacted in New Jersey (USA) to reduce nutrient inputs from fertilizers to water bodies in the state. A significant decrease of Z. marina biomass and areal cover occurred in this eutrophic estuary between 2004 and 2011 concomitantly with increasing nitrogen and phosphorus loading from the watershed. The rate of decline in aboveground and belowground biomass was significantly sharper during 2004-2006 than during 2008-2010. In 2010, Z. marina biomass dropped to a very low level (mean aboveground biomass = 7.7 g dry wt mDŽ mean belowground biomass = 27.0 g dry wt m&#452), persisting through the last sampling period (October-November) in 2013. Biomass and areal cover of Z. marina decreased even further after Fertilizer Law A2290 was enacted in January 2012, with the lowest values recorded from August to November each year. These low values are the result of ongoing eutrophication of the system. More seagrass monitoring and research are necessary in future years to determine if the fertilizer law will have a positive effect on Z. marina condition in the estuary over the long term.