Evaluating the success of horseshoe crab and migratory shorebird ...
Evaluating the success of horseshoe crab and migratory shorebird habitat restoration on Delaware Bay beaches damaged by Superstorm Sandy Niles and Associates Lawrence Niles, Dianne Daly & Joseph Smith American Littoral Society Tim Dillingham, William Shadel & Aleksandr Modjeski NJ Div Fish and Wildlife Amanda D. Dey & Matthew S. Danihel Stockton Coastal Research Center Steven Hafner Conserve Wildlife Foundation David Wheeler Wetlands Institute Lenore Tedesco & Lisa Ferguson
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Delaware bay’s horseshoe crabs population is the largest in the world PPIllerBefe w -Tgailliffrni*W-gr"J"SIWPyr- '
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Ruddy Turnstones, Semipalmated Sandpipers, Sanderling, Red Knot rely on Delaware Bay Crabs to breed
Long migrations leave birds emaciated and in need of easily digestible fat- producing horseshoe crab eggs
Bird numbers followed declines in overharvested horseshoe crabs. After 15 years of ineffective regulation, recovery remains elusive. .
Then hurricane sandy devastated delaware bay beaches in 2012, threatening another catastrophic loss of shorebirds
Our restoration began within months of Sandy and continues this year. The following slides describe the key aspects of the beaches and the response of both crabs and birds Moores Beach Before
Sand grain size 1.0
coarse sand
0.6 mm
Graphic mean (phi)
0.8 0.6 0.4 0.2
1 mm
0.0
restored
-0.2 -0.4
v. coarse sand
unrestored
Sand moisture 16 14
13.3%
% moisture
12 10 8 6
5.6%
4 2 0
restored unrestored
Horseshoe crab abundance control beaches restored beaches Thompsons beach
Mean horseshoe crab count per transect
400
300
200
100
0
May 12-18
May 19-23
May 26-30
Moores Beach: restoration increases spawning crabs 800
Horseshoe crab count per 50m transect mean +/- SE
restored in 2013
restored in 2014
600
mm
400
200
0
2013
2014
2013
2014
Horseshoe Crab Eggs
Egg cluster density control beaches restored beaches Thompsons Beach
Egg cluster density Per m2, 0-20cm deep (mean +/- SE)
30
20
10
0
May 12-18 May 19-23 May 26-30
Date
Jun 5-9
Jun 16-20
Jun 23-29
Embryo and larva cluster density control beaches restored beaches Thompsons Beach
Embryo and larva cluster density Per m2, 0-20cm deep (mean +/- SE)
30
20
10
0
May 12-18 May 19-23 May 26-30
Date
Jun 5-9
Jun 16-20
Jun 23-29
Less egg clusters at shallower sand depths Egg clusters 0-20cm deep per m2
25
20
15
Significantly lower egg density 30cm and below
10
5
0
0-10cm 11-20cm 21-30cm 31-40cm >41cm
Shorebird numbers
Red Knot
Ruddy Turnstone
Sanderling
Semipalmated Sandpiper
Sand movement from restoration sites • sand moved into tidal creek mouths • and into unrestored areas
-25%
-2% -3%
-38%
S. Reeds Cooks
Kimbles
Baycove
Pierces
Control beach – only 40% of sample sites were >40cm deep in 2013 while 100% were >40cm depth in 2014
Moores Beach Elevation change 3 months after restoration, 2014
1-2’ 0-1’ 0 -0-1’ -1-2’ -2-3’
Creek shoals, the most important crab and shorebird habitat on the bay
[email protected]
Our project goals for the next 2 years of restoration
South Fortescue
Restoring Thompsons Beach 2012 1932 1995 2002
We will re-create natural oyster reefs to improve beach resiliency
Oyster Reef Experiment on B. Hollinger shellfish lease will test impact of reefs and aquaculture racks on horseshoe crabs
Stockton Center for Coastal Resources will conduct a NJ bay-wide sentiment transport study to determine best path to long-term resiliency
American Littoral Society and Conserve Wildlife Foundation of NJ thanks: • • • • • • • • •
US Fish and Wildlife Foundation Community Foundation of NJ NJ Natural Lands Trust Partnership for Delaware Bay Estuary Inc. US Fish and Wildlife Service –Department of Interior Corporate Wetlands Restoration Partnership Downe, Maurice River, Middle Townships Cape May County NJ Division of Fish and Wildlife –NJ Dept of Environmental Protection
And volunteers from NJ and all over the world
•
•W I
Delaware bay’s horseshoe crabs population is the largest in the world PPIllerBefe w -Tgailliffrni*W-gr"J"SIWPyr- '
•-
•- r !
17: •2
7 ;
,T-t7- 4
Ruddy Turnstones, Semipalmated Sandpipers, Sanderling, Red Knot rely on Delaware Bay Crabs to breed
Long migrations leave birds emaciated and in need of easily digestible fat- producing horseshoe crab eggs
Bird numbers followed declines in overharvested horseshoe crabs. After 15 years of ineffective regulation, recovery remains elusive. .
Then hurricane sandy devastated delaware bay beaches in 2012, threatening another catastrophic loss of shorebirds
Our restoration began within months of Sandy and continues this year. The following slides describe the key aspects of the beaches and the response of both crabs and birds Moores Beach Before
Sand grain size 1.0
coarse sand
0.6 mm
Graphic mean (phi)
0.8 0.6 0.4 0.2
1 mm
0.0
restored
-0.2 -0.4
v. coarse sand
unrestored
Sand moisture 16 14
13.3%
% moisture
12 10 8 6
5.6%
4 2 0
restored unrestored
Horseshoe crab abundance control beaches restored beaches Thompsons beach
Mean horseshoe crab count per transect
400
300
200
100
0
May 12-18
May 19-23
May 26-30
Moores Beach: restoration increases spawning crabs 800
Horseshoe crab count per 50m transect mean +/- SE
restored in 2013
restored in 2014
600
mm
400
200
0
2013
2014
2013
2014
Horseshoe Crab Eggs
Egg cluster density control beaches restored beaches Thompsons Beach
Egg cluster density Per m2, 0-20cm deep (mean +/- SE)
30
20
10
0
May 12-18 May 19-23 May 26-30
Date
Jun 5-9
Jun 16-20
Jun 23-29
Embryo and larva cluster density control beaches restored beaches Thompsons Beach
Embryo and larva cluster density Per m2, 0-20cm deep (mean +/- SE)
30
20
10
0
May 12-18 May 19-23 May 26-30
Date
Jun 5-9
Jun 16-20
Jun 23-29
Less egg clusters at shallower sand depths Egg clusters 0-20cm deep per m2
25
20
15
Significantly lower egg density 30cm and below
10
5
0
0-10cm 11-20cm 21-30cm 31-40cm >41cm
Shorebird numbers
Red Knot
Ruddy Turnstone
Sanderling
Semipalmated Sandpiper
Sand movement from restoration sites • sand moved into tidal creek mouths • and into unrestored areas
-25%
-2% -3%
-38%
S. Reeds Cooks
Kimbles
Baycove
Pierces
Control beach – only 40% of sample sites were >40cm deep in 2013 while 100% were >40cm depth in 2014
Moores Beach Elevation change 3 months after restoration, 2014
1-2’ 0-1’ 0 -0-1’ -1-2’ -2-3’
Creek shoals, the most important crab and shorebird habitat on the bay
[email protected]
Our project goals for the next 2 years of restoration
South Fortescue
Restoring Thompsons Beach 2012 1932 1995 2002
We will re-create natural oyster reefs to improve beach resiliency
Oyster Reef Experiment on B. Hollinger shellfish lease will test impact of reefs and aquaculture racks on horseshoe crabs
Stockton Center for Coastal Resources will conduct a NJ bay-wide sentiment transport study to determine best path to long-term resiliency
American Littoral Society and Conserve Wildlife Foundation of NJ thanks: • • • • • • • • •
US Fish and Wildlife Foundation Community Foundation of NJ NJ Natural Lands Trust Partnership for Delaware Bay Estuary Inc. US Fish and Wildlife Service –Department of Interior Corporate Wetlands Restoration Partnership Downe, Maurice River, Middle Townships Cape May County NJ Division of Fish and Wildlife –NJ Dept of Environmental Protection
And volunteers from NJ and all over the world
