Beneficial Reuse of Dredge Material for Salt Marsh Restoration: Early Recovery of Vegetation and Epifaunal Macroinvertebrate

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1 Metthea Yepsen Adrianna Zito-Livingston Jessie Buckner Projects funded by New Jersey Department of Environmental Protection and Department of Transportation, The National Fish and Wildlife Foundation, and The U.S. Army Corps of Engineers Photo credit: Metthea Yepsen/ TNC Beneficial Reuse of Dredge Material for Salt Marsh Restoration: Early Recovery of Vegetation and Epifaunal Macroinvertebrate

2 Outline Introduction to project What is beneficial reuse of dredged materials? Where are the project locations? Monitoring Vegetation EMI Results Placement Vegetation EMI What next? 2

3 Photo credit: Jackie Jahn, TNC Piloting the beneficial re use of dredged material for salt marsh restoration in New Jersey

4 Project Locations Fortescue Project Timelines Middle Township (Ring Island) Avalon Summer 2014~ 1 acres Black Skimmer Habitat and ~ 2 acre thinlayer placement Dec. 14 Jan. 15: ~6 acres marsh Nov. 15 Feb 16: ~ 42 acres marsh Fortescue Feb April 16; Dec Jan 16/ 17: ~14 acres marsh, 2 acres dune, 700 ft beach Avalon Middle Twsp. 4

5 Video by TNC Ring Island (during construction 2014) 5

6 Ring Island After Two Growing Seasons Photo: Damon Noe, TNC

7 Avalon Photo: Damon Noe (TNC) 7

8 Avalon After One Growing Season Photo: Damon Noe, TNC

9 Fortescue 9 drone photo by Damon Noe, fall 2016 (TNC)

10 Fortescue after one growing season Placed sediments Fortescue After One Growing Season Damage from machines Signs of vegetation recovery Aug Photo: Damon Noe, TNC 10

11 Monitoring June 24 th 2016 September 20 th 2016 Photo: Jessie Buckner, TNC Photo: Jaci Wollard, NJDEP 11

12 Study Design Acres: 42 Permanent Placement Plots: 54 Percent received sediment: 91 Acres: 23 Permanent Placement Plots: 77 Percent received sediment: 19 Acres: 2 Permanent Placement Plots: 24 Percent received sediment: 92 12

13 Vegetation and EMI Metrics Vegetation (1 m2 plot) Percent cover Stem height of dominant plant species Above and belowground biomass EMI (1/4 m2 sub plot) Species richness Categorical abundance of species Categorical abundance of crab burrows Depth of water Depth of sediment placement Photo of plot 13

14 Vegetation Monitoring Before After Photos: Metthea Yepsen, TNC 14

15 EMI Monitoring Epifaunal Macroinvertebrates Marsh snails (Melampus bidentatus) Mud dog whelks (Ilyanassa obsoleta) Mouse ear marsh snail (Ovatella myosotis) Common periwinkle (Littorina littorea) Ribbed Mussels (Geukensia demissa) Fiddler crab (Uca Pugnax) Purple marsh crab (Sesarma reticulatum) Burrows Crabs (p/a) Photos by TNC during monitoring Mud dog whelk (Ilyanassa obsoleta) next to quad marker. Marsh snail (Melampus bidentatus) aggregation 15

16 Results 90 Average depth of placement (cm) Placement Error bars are SD Ring Island Avalon Fortescue *Avalon average depth greater than shown. Depths >100m calculated as 100cm 16

17 Results Average depth of placement (cm) at Avalon comparing pools and marsh platform Pools Marsh platform Error bars are SD *depth in pools greater than shown. Depths >100cm calculated as 100cm 17

18 Results Ring Island: depth of placement 18

19 Results Vegetation cover at sites based on plot data Pre PP1 PP2 Pre PP1 Pre PP1 Ring Island Avalon Fortescue Control Placement Error bars are SD 19

20 Results 3.5 Average vegetation species richness/ m Control Placement Pre PP1 PP2 Pre PP1 Pre PP1 Ring Island Avalon Fortescue Error bars are SD 20

21 Results Average stem height of Spartina alterniflora (cm) Pre PP1 PP2 Pre PP1 Pre PP1 Ring Island Avalon Fortescue Error bars are SD Control Placement 21

22 Results Average EMI Richness per 0.25m 2 by site Control Placement Pre PP1 PP2 Pre PP1 Pre PP1 Error bars are SD Ring Island Avalon Fortescue 22

23 Results 3.5 Average EMI Richness by Habitat 1 year post placement Control Placement Error bars are SD Vegetated Unvegetated Pool Vegetated Unvegetated Pool Vegetated Unvegetated Pool Ring Island Avalon Fortescue Habitat is calculated by taking the average of the midpoints of the observed Braun-blanquet cover classes for each habitat type (Pool, Vegetated, Unvegetated). A plot must have at least 51% cover to be considered that habitat type. 23

24 Is Using Dredged Material for Marsh Restoration a Win Win Situation? The Jury is still out. It can provide sediment to marshes impacted by rising sealevel, subsidence, and erosion. It can provide a viable dredged material management alternative There is an initially large effect on the marsh ecosystem that will require time to recover Big project-specific questions to answer include: How long does it take for the marsh to be restored? Are there long-term negative impacts of such projects? Are there ways we can use this method that have less of an initial effect on the marsh ecosystem? Photo: Damon Noe, TNC

25 What Now? Monitoring, adaptive management, and sharing lessons learned Photo: Jessie Buckner, TNC Photo: Jaci Wollard, TNC Photo: M Yepsen, TNC 25

26 Metthea Yepsen Coastal Projects Manager 26