Seaweeds of the Brave Boat Harbor salt marsh and adjacent open coast of southern Maine

46 Pages·2001·20.8 MB·English

by  A C Mathieson

RHODORA,
Vol. 103, No. 913, 1-46, 2001
pp.
HARBOR
SEAWEEDS OF THE BRAVE BOAT SALT
MARSH AND ADJACENT OPEN COAST OF SOUTHERN
MAINE
Arthur Mathieson
C.
Department of Plant Biology and Jackson Estuarine Laboratory,
NH
New
Durham, 03824
University of Hampshire,
[email protected]
e-mail:
Dawes
Clinton
J.
FL
Department of Biology, University of South Florida, Tampa, 33620
Michelle Anderson
L.
Biology Program and Jackson Estuarine Laboratory,
NH
New
Durham, 03824
University of Hampshire,
Edward
Hehre
J.
Department of Plant Biology and Jackson Estuarine Laboratory,
NH
New
Durham, 03824
University of Hampshire,
A
abstract. comparison of species richness 51 coastal and estuarine
at
Maine encompassing from Cape Neddick,
sites in southern given, the area
is
York, to Fort Foster, Kittery, and including the Brave Boat Harbor salt marsh
A
(York/Kittery). of 148 taxa was recorded, which relatively high
total
is
New
compared to other coastal or estuarine areas in northern England. Sea-
weed populations exhibited three major distributional patterns: coastal (41%),
coastal-estuarine (51%), and estuarine (8%). Perennial species dominated
open coastal and outer estuarine locations, while annuals were most conspic-
uous at inner estuarine sites. Twenty-nine taxa were restricted to a single site
(2% occurrence), whereas 19 were found 21-36 (41-71% occurrence).
at sites
Diversity in Brave Boat Harbor's main tidal channel was relatively high (83
species), presumably because of coastal and estuarine influences, diversity of
uncommon
new
habitats, and limited anthropogenic impacts. Six or seaweeds
were recorded from Brave Boat Harbor, including the invasive green alga
Codium Urospora
fragile subsp. tomentosoides, the green algal epiphyte cur-
brown Melanosiphon
vata, the tubular opportunistic alga intestinalis, the en-
tangled or partially embedded ecads Fucus vesiculosus ecad volubilis and F.
spiralis ecad lutarius, and a dwarf embedded moss or "muscoides-like" Fu-
cus. The prolific growth of psammophytic populations of F. spiralis on sandy
bluffs Brave Boat Harbor also unique, as typically grows on hard
at
is it
substrata within contiguous muddy estuaries. was most abundant in the
It
outer third of the Harbor, along with detached ecad lutarius. Ascophyllum
its
nodosum ecad scorpioides and F. vesiculosus ecad volubilis grew commonly
as detached or buried populations in the interior parts of the Harbor, while
the "muscoides-like ,, Fucus was found on outer high sandy marsh surfaces.
1
Rhodora
2
[Vol. 103
Key Words: seaweeds, ecology. Brave Boat Harbor marsh, nearshore
salt
open southern Maine.
coast,
marshes Maine
Salt in are rather limited both occurrence
in
and area] coverage (Jacobson and Jacobson 1989; Jacobson
et
al.
No
1987). major wetlands occur within two of
tidal the state's
embayments, Cobscook Bay
largest extreme eastern Washing-
in
County Bay Fundy
ton (an extension of the of with wide-ranging
tidal amplitudes and swift currents) and the sheltered Penobscot
Bay region of Hancock, Waldo, and Knox
Counties. Small, mar-
ginal marshes occur from midcoastal Lincoln and Sagadahoc
tidal
Counties Casco Bay (Cumberland
to County). Further south,
broad expanses
of wetlands Scarborough,
tidal in Wells, York,
and Kittery are comparable to those of the Great Bay Estuary
New
System Maine
of and Hampshire, Hampton-Seabrook
the
New
marsh Hampshire, and many marshlands
in large extending
from the Merrimack and Parker Rivers Cape Cod, Massachu-
to
setts.
As Mann
noted by seaweeds
(1982), estuarine play
a variety
of functional roles northern marshes, including primary
in salt
production, provision of numerous
critical habitat for organisms,
and production of abundant
organic matter via cycles.
detrital
Although
these roles are generally understood, there are few de-
tailed assessments of seaweed communities Maine marsh-
in salt
es, except for floristic descriptions of the York River Estuary
(Mathieson and
et 1993) inner riverine sections of the Great
al.
Bay
Estuary System, including the Piscataqua and Salmon
Falls
Rivers (Mathieson and Hehre 1986; Mathieson and Penniman
1991).
The
present study intended com-
to characterize the species
is
and
position variability spatially and temporally) of estuarine
(i.e.,
and nearshore open seaweed between Cape
coastal populations
Neddick, York, and Maine
Fort Foster, Kittery, (Figures 1-3),
including those of Brave Boat Harbor
(hereafter designated as
BBH). The
represents one of major
latter site three estuaries with-
from
in this area, including, north to south (Figures and the
2),
1
BBH
York
River (Maine), (Maine), and the Piscataqua River
New
(Maine and Hampshire). The Harbor
located the town-
is in
ships of York and Kittery, Maine, and partly owned by the
is
National Wildlife Fedcration/U.S. Fish and Wildlife Service
with-
—
Mathieson Seaweeds of Brave Boat Harbor
2001] et al. 3
o 40
7
>
l
MAINE
42°
5
GULF OF MAINE
-
ESTUARY
YORK RIVER
BRAVE BOAT HARBOR
GREAT
BAY
ESTUARY SYSTEM
NEW
HAMPSHIRE
-SEABROOK
HAMPTON
ESTUARY SYSTEM
43°20'
MERRIMACK RIVER
MASS.
ESTUARY
MILE
I
New
Figure The coastline of northern England between southern
1.
Maine and northern Massachusetts, showing diverse coastal and estuarine
habitats.
in Rachel Carson Wildlife Reserve (ca. 162 ha). has a rich
its It
human when
history dating back to at least 1645, sections of the
marsh were alloted to residents for fodder and the rearing of cattle
Records from
(archives, Kittery Historical Society). the early
BBH
1700s detail the geography of and interrelationship with
its
Gerrish Island, Cutts Island, Chauncey Creek, and the Kittery
'
4 Rhodora
[Vol. 103
1
i
3
7 4
70°45' °
YORK POND
-
CN
MAINE
YORK
43°06' -
RIVER
YORK
KITTERY
1
BRAVE BOAT
j^T
v^
HARBOR BBHS
'"CUTTS /lO -
1-
"^•SP
[•SISP
Cgerrish
<^>
1
#
PISCATAQUA RIVER
43°04'
5km
NEW HAMPSHIRE
ATLANTIC OCEAN
l
New
Figure Southern Maine and Hampshire showing
2. coastlines, the
location of coastal and estuarine habitats. See Appendix for abbreviations.
Point mainland (Figures 2 and Both and Chauncey
islands
3).
Creek named
Samuel
are for original Drake's
settlers (cf. travel
memoirs,
archives, Kittery Historical Society).
The
goals of our study were compare
three-fold: to the
(1)
number
and types of seaweeds from and
six coastal estuarine
BBH
habitats (Figures 2 and including
the area of York/Kit-
3),
Maine;
provide would
tery, to a detailed baseline
(2) floristic that
aid in future conservation of these valuable habitats; to com-
(3)
BBH
pare and
distributional patterns with other
floristic in estu-
New
aries within northern England.
—
Mathieson Seaweeds Brave Boat Harbor
of
2001] et 5
al.
YORK
A
CHAUNCEY CREEK
GERRISH ISLAND
ATLANTIC OCEAN
Figure The twenty-one estuarine study along the main channel of
3. sites
Brave Boat Harbor (BBH), plus 23 other within four contiguous
sites tidal
The "A" "B"
tributaries. dashed lines at letters and indicate the locations of
road crossings and culvert at tributaries #1 and #4, respectively, while letter
"C"
designates the approximate delineation of town boundaries between
York and
Kittery.
MATERIALS AND METHODS
made Maine
Seasonal collections were 51 southern
at sites in
(Figures 2 and Appendix): seven nearshore open coastal
3; lo-
cations between Cape Neddick, York (43°09.93'N, 70°35.41'W),
and Fort Foster, Kittery, on the outermost Piscataqua River
(43°04.0'N, 70°41.77'W); 21 estuarine along the main chan-
sites
BBH,
nel of York/Kittery (43°06.0'N, 70°39.33'W); 23 additional
Rhodora
6
[Vol. 103
BBH
estuarine four contiguous of and
sites in tidal tributaries
connected marshes (Figure Descriptions of each
salt 3). site, in-
cluding and given Appen-
location, habitats, substrata, are the
in
dix. Periodic sampling of coastal populations was conducted be-
tween 1965-1985 Mathieson and Hehre
1986), while addi-
(cf.
BBH
tional seasonal sampling of these and various was done
sites
between 1997-1999.
Methods
of collection and identification are similar to those of
Mathieson
et (1998), with seasonal collections of conspic-
al. all
uous seaweeds from diverse intertidal (on foot) and shallow sub-
SCUBA).
tidal habitats (by Samples were returned (within one
hour after being collected) to the Jackson Estuarine Laboratory,
where they were identified and prepared as voucher specimens.
The Adey
following taxonomic references were and
utilized:
Adey McLachlan
1973; Bird and 1992; Blair 1983; Bliding 1963,
1968; Blomster et 1999; Burrows 1991; Dixon and Irvine
al.
Wegeberg
1977; Diiwel and 1996; Farlow 1881; Fletcher 1987;
Hoek
Harper and Saunders, 2000; 1963, 1982; Irvine 1983; Irvine
Maggs Hommer-
and Chamberlain 1994; Kingsbury 1969; and
sand 1993; Schneider and Searles 1991; Sears 1998; Silva
et
al.
Webber
1996; Taylor 1957; Villalard-Bohnsack 1995; and Wilce
Wynne
1971; Woelkerling 1973; and Heine The nomen-
1992).
employed
clature primarily follows South and Tittley (1986), ex-
cept for recent changes noted by Sears (1998) and Silva
et al.
Approximately 3500 voucher specimens documenting
(1996).
these studies have been deposited the Albion R. Hodgdon Her-
in
New
barium Hampshire
the University of (nha).
at
Several comparisons have been made: compila-
fioristic a
(1)
number
tion of species composition and of taxa each
at site; (2)
an enumeration of percentage and mean number
of taxa for
total
each of the six major coastal and estuarine habitats; a sum-
(3)
mary
of intraspecific patterns for total taxa in each habitat (e.g.,
BBH
number number
the of taxa 21 an assessment of
at sites); (4)
and percentage of shared taxa each major Percent
for habitat.
similarity values (C) were determined using Czekanowski's co-
(Bray and
efficient Curtis 1957):
2W
=
C
+
b
a
where "a" the number of taxa the tfc b" the
is at first site, is
—
Mathieson Seaweeds Brave Boat Harbor
of 7
et
2001 al.
J
"W"
number number
at the second site, and is the of taxa in
common
to both.
Longevity were enumerated according
characteristics to the
scheme outlined by Knight and Parke (1931), with taxa desig-
nated as annuals (aseasonal or seasonal), perennials, or pseudo-
perennials, depending upon their span, growth, and repro-
life
ductive characteristics (Mathieson 1989). Delineations were
New
based upon throughout England (Coleman and
studies
field
Mathieson Femino and Mathieson Hehre and Ma-
1975; 1980;
Lamb Zimmerman
Hehre and
thieson 1970; 1970; 1964;
et
al.
Ma-
Mathieson Mathieson and Hehre
1979; 1982, 1983, 1986;
thieson 1993, 1996, 1998; Mathieson, Hehre and Reynolds
et
al.
1981; Mathieson and Penniman 1986a, 1986b, 1991; Mathieson,
Reynolds and Hehre 1981; Reynolds and Mathieson 1975; Sears
Webber The
and Wilce 1975; Stone 1970; and Wilce 1971).
et
al.
number
and percentage of annual and perennial taxa each of
at
major were enumerated.
the six habitats
BBH
We
compared mean number
the of taxa per site in the
area and thirteen other estuaries between the York River in Maine
and the Merrimack River Massachusetts (Figure The
in lo-
1).
number
cation, of collecting sites, and extent of tidal limits for
BBH
the area are summarized in the Appendix. Similar data,
based upon previous publications (Mathieson and Fralick 1972,
Mathieson and Hehre Mathieson
1973; 1986; et 1993), giv-
al. is
ME,
below York 20
en for the other estuarine habitats: River,
NH
ME,
and 0-7.5 km; Piscataqua and 59 and
River,
sites sites
NH,
0-19.4 km; Bay, and 13.8-19.8 km; Great
21
Little sites
Bay, NH, 16 and 20.6-25.1 km; Bellamy River, NH, 10
sites sites
NH,
and 16.6-22.9 km; Cocheco River, 17 and 20.2-25.3
sites
km; Lamprey NH, and 25.3-28.0 km; Oyster
River, 9 sites River,
NH
NH, 14 and 18.4-22.7 km; Salmon Falls River, and ME,
sites
NH,
16 and 20—26.4 km; Squamscott River, 16 and
sites sites
25.9-36.3 km; Winnicut NH, 4 and 25.4-27.7 km;
River,
sites
NH,
Hampton-Seabrook 49 and 0.6—5.9 km;
Estuary, the
sites
MA,
Merrimack River Estuary, 19 and 0-13.7 km.
sites
Seasonal measurements of surface water temperatures and
sa-
BBH
were recorded seven the main channel of
linities at sites in
km
(Figure extending from the mouth (site #1, 0.1 inland) to
3),
km
Road
headwaters near Brave Boat Harbor #19, 1.6
tidal (site
This was accomplished using hand-held thermometer
inland). a
and refractometer, with an accuracy of °C and 0.5%c, respec-
0.1
Rhodora
8 [Vol. 103
Analogous sampling was done seven along
tively. at sites tribu-
which and
tary #1, delineates Cutts Island has "coastal environ-
ments" both ends (Figure Appendix). #la
at 3; Site located
is
km
0.53 and 4.2 from the Harbor's mouth and open coast near
km
Sewards Cove, respectively, while #lj 2.0 and 2.7 from the
is
same
geographical Most sampling was done
locations. pre-
at
dicted low tides (Anonymous 1996), proceeding from outer to
inner areas relative to the Harbor's mouth.
HABITAT INSCRIPTION AND ECOLOGY
The coastline between Cape Neddick, Maine, and Portsmouth
New
Hampshire many
Harbor, (Figure has geological and
to-
2),
common.
pographical features in These include the presence of
scattered offshore islands (Boon Island and of Shoals), broad
Isles
arcuate bays, large rocky headlands, and scattered sandy barrier
beaches front of extensive marshes Mathieson and
in salt
(cf.
Hehre The compared
1986). terrain relatively with coastal
is flat
Bedrock composed
regions to the northeast. primarily of low-
is
grade metasedimentary rock intruded by large plutons of granite
and syenite (Belknap 1987; Kelley 1987; Mathieson
et al. et al.
Wave
1991). action on the nearshore open coast variable, from
is
exposed (Cape Neddick), semi-exposed and
(Seapoint)
to shel-
tered (Fort Foster). Substrata vary from massive rock outcrops
to
boulders, cobbles, and sand Appendix). Three major
(cf. estuaries
are located sequentially between Cape Neddick and Portsmouth
BBH
Harbor (Figures and the York River Estuary, the marsh
2):
1
complex
(including the Cutts and Gerrish Island marshes), and
The
the Piscataqua River. York and Piscataqua Rivers are the
km
largest estuarine habitats, extending 7.5 and 19.4 inland,
re-
spectively; headwaters of the former are York Pond (Mathieson
at
merges
et al. 1993); the latter into Little Bay, Great Bay, and the
km
Squamscott
River (Figure extending 36.3 inland (Mathie-
1),
BBH
son and Hehre The main
1986). channel about
tidal at
is
km
1.9 in length; Cutts and Gerrish Island marshes are inner
tidal
km
and extend 0.39-4.2 and 2.4-4.2
tributaries inland, respec-
Appendix).
tively
(cf.
km
Brave Boat Harbor (about 2.7 2 located behind sand
a
is
)
and cobble barrier beach near Seapoint (Figures 2 and Appen-
3;
dix). The sand body inside the mouth of the Harbor resembles a
(Boothroyd However,
flood tidal delta 1978). the currents are
—
Mathieson Seaweeds of Brave Boat Harbor 9
2001] et
al.
weaker than those of classical mesotidal estuaries like the Parker
Bay somewhat
River and Essex Massachusetts and provide a
in
different configuration (Franz Anderson, pers. comm.). Tides near
BBH
the mouth of are uniformly semi-diurnal, with an average
m
(Anonymous
amplitude of about 2.6 1996). Currents and pe-
mouth
from
riodic inundations cause variable salinities the to the
Road
headwaters Brave Boat Harbor (see below).
tidal at
BBH
The main channel of divided by the York and Kittery
is
town Although populated and devoid
(Figure sparsely
line
3). it is
Harbor
of industry, shellfish harvesting restricted to the outer
is
due to contamination by fecal coliform bacteria. Tributaries #1
#4 show some presumably due
and signs of eutrophication, to
septic discharge.
BBH
The marshes were probably formed about 10,000
salt
years before present (YBP), following the retreat of the Wis-
last
consin ice sheet and subsequent stabilization of sea levels (Belk-
nap et 1987; Jacobson and Jacobson 1989; Jacobson et al.
al.
Most marshes Gulf of Maine flourished during
1987). tidal in the
time, upper bays behind coastal sand barriers and di-
this filling
minishing their tidal channels into smaller creeks. Like other salt
BBH
marshes between southern Maine and Massachusetts, re-
How-
ceives an abundance of fresh water (Jacobson et 1987).
al.
more sandy and erosive environment than the York
ever, a
is
it
marshes
and Piscataqua Rivers or the Cutts and Gerrish Islands
(Mathieson and Hehre Mathieson and
1986; et al. 1993), it is
New
Hampton-Sea-
more analogous geologically Hampshire's
to
brook Estuary (Mathieson and Fralick 1972) and the Parker River
area of Massachusetts (Boothroyd 1978). There extensive ero-
is
sion of BBH's outer marsh (Figure possibly reflecting strong
4),
(Stevenson and
tidal currents, rising sea levels et al. 1986), re-
New
England and
duced sediments due expansion of forests
to
increased conservation measures over the past 100 years.
soil
Many
marsh
deep ponds and potholes occur the outer (see
in
from
below), probably caused by ice rafting, surface collapse un-
dermining of the sand and dieback of marsh grass because
layer,
of wrack deposition. Thus, the outer marsh shows a patchy phys-
iography, with extensive dissection and superficial channels.
BBHN
BBHS;
The BBH's main and
channel
entrance
to (sites
Ap-
Figures 2 and dominated by boulders and cobbles
3) (cf.
is
pendix), which were probably deposited after the retreat of the
YBP
Laurentide Glacier about 50,000 (Kelley 1987). Just inside
10 Rhodora
Vol. 103
|
/
*J \. J
Figure 4. Photographs of the main tidal channel o( Brave Boat Harbor-
m
showing (A) the broad, sandy mouth and (B) nearby eroded bluffs (1.5-3
high) with high marsh vegetation consisting of Spartina patens (SP) and an
understory of the dwarf muscoides-like Fucus. Fucus spiralis (FS) attached
is
to the sediment below the high marsh while Pilayella littoralis occurs as
strands hanging from
the
cliff.
the Harbor's mouth, the shoreline sandy and resembles Hood
is a
tidal delta (Boothroyd 1978). The exposed nature of area
this
is
demonstrated by
several features: (1) surface ripples on the sand
caused by tidal currents; (2) absence of a low marsh with Spartina
alterniflora Loisel.; extensive erosion and slumping of
(3) the