Abstract
With the increasing appreciation that sea grass habitats are in global decline, there is a great need to be able to efficiently and effectively assess and characterize the status and trends of sea grass in our coastal ecosystems. This paper examines the utility of remotely sensed vs. in situ plot-based monitoring using the Barnegat Bay-Little Egg Harbor (BB-LEH), New Jersey, USA estuarine system as a case study. Eelgrass (Zostera marina) is the dominant species, while widgeon grass (Ruppia maritima) is also common in lower salinity regions of the BB-LEH. Aerial imagery collected during the months of July and August 2009 was interpreted and mapped using object based image analysis techniques, similar to techniques used in the 2003 mapping survey of this system. Boat-based in situ monitoring data were collected concurrently with the aerial photography to assist the image interpretation and for an independent accuracy assessment. We compared the remotely-sensed mapping of sea grass cover change (in 2003 vs. 2009) vs. in situ plot-based monitoring conducted from 2004 through 2009. Comparison of the remotely-sensed vs. the in situ plot-change analysis suggests that the two methodologies had broadly similarly results, with the percent area showing declines in sea grass cover greater than those that exhibited increases. In conclusion, the two studies provide corroborating evidence that sea grass has declined in percent cover in the BB-LEH system during the decade of the 2000’s. While remotely-sensed surveys provide synoptic information for a “big picture” view on sea grass distribution, site specific in situ sampling is required to determine other aspects of sea grass status, e.g. above vs. below-ground biomass, blade length, shoot density, epiphytic loading, etc. Either method alone gives an incomplete picture. As demonstrated in this study, to fully characterize the spatial extent, health, and density of sea grass meadows across the entire estuary, combining remote sensing surveys concomitantly with comprehensive in situ assessment provides the most robust approach.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Beem NT, Short FT (2008) Sub tidal eelgrass declines in the great bay estuary, new Hampshire and Maine, USA. Estuar Coasts 32:202–205
Blaschke T (2010) Object based image analysis. ISPRS J Photogramm Remote Sens 65(1):2–16
Bricker SB, Ferreira JG, Simas T (2003) An integrated methodology for assessment of estuarine trophic status. Ecol Model 169:39–60
Burkholder J, Tomasko D, Touchette B (2007) Sea grass and eutrophication. J Exp Mar Biol Ecol 350:46–72
Dobson JE, Bright EA, Ferguson RL, Field DW, Wood LL, Haddad KD, Iredale H, Jensen JR, Klemas VV, Orth RJ, Thomas JP (1995) NOAA coastal change analysis program (C-CAP): guidance for regional implementation. NOAA Technical Report NMFS 123, Washington
Ferguson RL, Wood LL, Graham DB (1993) Monitoring spatial change in sea grass habitat with aerial photography. Photogramm Eng Remote Sens 59:1033–1038
Fertig B, Kennish MJ, Sakowicz GP (2013) Changing eelgrass (Zostera marina L.) characteristics in a highly eu trophic temperate coastal lagoon. Aquat Bot 104:70–79
Fertig, B, Kennish MJ, Sakowicz GP, Reynolds LK (2014) Mind the Data Gap: Identifying and assessing drivers of changing eutrophication condition. Estuaries and Coasts Online First.
Finkbeiner, M, Stevenson B, Seaman R (2001) Guidance for benthic habitat mapping: an aerial photographic approach. NOAA CSC 20117-PUB. http://www.csc.noaa.gov/benthic/mapping/pdf/bhmguide.pdf
Gastrich MD, Lathrop RG, Haag S, Weinstein MP, Danko M, Caron D, Schaffner R (2004) Assessment of brown tide blooms, caused by Aureococcus anophagefferens, and contributing factors in New Jersey coastal bays: 2000–2002. Harmful Algae Special Issue Brown Tides 3:305–320
Handley L, Altsman D, DeMay R (eds) (2007) Seagrass status and trends in the Northern Gulf of Mexico: 1940–2002: U.S. Geological Survey Scientific Investigations Report 2006–5287, 267 p.
Kendrick GA, Hegge BJ, Wyllie A, Davidson A, Lord DA (2000) Changes in sea grass cover on success and parmelia banks, Western Australia between 1965 and 1995. Estuar Coast Shelf Sci 50:341–353
Kennish MJ, Haag SM, Sakowicz GP (2008) Seagrass demographic and spatial habitat characterization in little egg harbor, New Jersey, using fixed transects. J Coast Res SI 55:148–170
Kennish MJ, Haag SM, Sakowicz GP (2010) Seagrass decline in New Jersey coastal lagoons: a response to increasing eutrophication. In: Kennish MJ, Paerl HW (eds) Coastal lagoons: critical habitats of environmental change. Taylor and Francis Publishers, Boca Raton, pp 167–201
Kurz RC, Tomasko DA, Burdick D, Ries TF, Patterson K, Finck R (2000) Recent trends in sea grass distributions in southwest Florida coastal waters. In: Bortone SA (ed) Sea grasses: monitoring, ecology, physiology and management CRC Press, Boca Raton, FL, pp 157–166.
Lathrop RG, Haag SM (2011) Assessment of Seagrass Status in the Barnegat Bay – Little Egg Harbor Estuary System: 2003 and 2009. Center for Remote Sensing & Spatial Analysis, Rutgers University, New Brunswick, NJ. 56 p. http://crssa.rutgers.edu/projects/coastal/sav/downloads/CRSSAreport2011-01_Assessment_Seagrass_in_BBAY_LEH_2003_and_2009.pdf
Lathrop RG, Styles RM, Seitzinger SP, Bognar JA (2001) Use of GIS mapping and modeling approaches to examine the spatial distribution of sea grasses in Barnegat Bay, New Jersey. Estuaries 24(6):904–916
Lathrop RG, Montesano P, Haag SM (2006) A multi-scale segmentation approach to mapping sea grass habitat using airborne digital camera imagery. Photogramm Eng Remote Sens 72(6):665–675
Macomber RT, Allen D (1979) The New Jersey submerged aquatic vegetation distribution atlas final report. Earth Satellite Corporation, Washington
Moore KA, Wilcox DJ, Orth R (2000) Analysis of abundance of submersed aquatic vegetation communities in the Chesapeake Bay. Estuaries 23:115–127
Orth RJ, Batiuk RA, Bergstrom PW, Moore KA (2002) A perspective on two decades of policies and regulations influencing the protection and restoration of submerged aquatic vegetation in Chesapeake Bay, USA. Bull Mar Sci 71:1391–1403
Orth RJ, Carruthers TJB, Dennison WC, Duarte CM, Fourqurean JW, Heck KL, Hughes AR, Kendrick GA, Kenworthy WJ, Olyarnik S, Short FT, Waycott M, Williams SL (2006) A global crisis for sea grass ecosystems. BioScience 56(12):987–996
Orth R, Marion SR, Moore KA, Wilcox DJ (2010) Eelgrass (Zostera marina L.) in the Chesapeake Bay region of the Mid-Atlantic coast of the USA: challenges in conservation and restoration. Estuaries and Coasts 33:139–150
Orth RJ, McGlathery KJ (2012) Eelgrass recovery in the coastal bays of the Virginia Coast Reserve, USA. Mar Ecol Prog Ser 448:173–176
Robbins BD, Bell SS (1994) Seagrass landscapes: a terrestrial approach to the marine sub tidal environment. Trends Ecol Evol 9:301–304
Scavia D, Bricker SB (2006) Coastal eutrophication assessment in the United States. Biogeochemistry 79:187–208
Short FT (2007) Eelgrass Distribution in the Great Bay Estuary: 2005. Final Report to the New Hampshire Estuaries Project. University of New Hampshire, Durham, NH. http://www.prep.unh.edu/resources/pdf/eelgrass_distribution_in-unh-07.pdf
Short FT, McKenzie LJ, Coles RG, Vidler KP (2002) Sea grass net manual for scientific monitoring of sea grass habitat. QDPI, Cairns
Short FT, McKenzie LJ, Coles RG, Vidler KP, Gaeckle JL (2006) Sea grass Net Manual for Scientific Monitoring of Seagrass Habitat, Worldwide edition. University of New Hampshire Publication. 75 pp. http://marine.unh.edu/jel/faculty/fred2/seagrassnet-manuals/seagrassnet-manual-08.pdf
Waycott M, Duarte CM, Carruthers TJB, Orth RJ, Dennison WC, Olyarnik S, Calladine A, Fourqurean JW, Heck KL, Hughes AR, Kendrick GA, Kenworthy WJ, Short FT, Williams SL (2009) Accelerating loss of sea grasses across the globe threatens coastal ecosystems. PNAS 106(3):12377–12381
Wazniak CE, Hall MR, Carruthers TJB, Sturgis B, Dennison WC, Orth RJ (2007) Linking water quality to living resources in a Mid-Atlantic lagoon system. Ecol Appl 17(5):S64–S78
Acknowledgments
This project was funded by the Barnegat Bay Partnership, the New England Interstate Water Pollution Control Commission and the New Jersey Agricultural Experiment Station. We express our sincere appreciation for the assistance of Gina Petruzzelli, Greg Sakowicz, Chris Huch and the staff at Rutgers University Marine Field Station in the collection of the field reference data.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Lathrop, R.G., Haag, S.M., Merchant, D. et al. Comparison of remotely-sensed surveys vs. in situ plot-based assessments of sea grass condition in Barnegat Bay-Little Egg Harbor, New Jersey USA. J Coast Conserv 18, 299–308 (2014). https://doi.org/10.1007/s11852-014-0319-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11852-014-0319-y