Ecology of Red Maple Swamps in the Glaciated Northeast: A ...

was the most likely reason for differences in cammunity
stnxeture heLween floodplain and nonfloodplain
sites.
Wether stand structure in nonfloodplain red
maple? swamps variee with water regime is unclear.
%e density and basal area have been
shown to h bt,h higher (Ehrenfeld and Gulick
1981; I ~wry 1984) and lower (Ehrenfeld 1986;
Paratley and Mley 1986) on wetter sites. Cornpariaon
of results of diffc?rent, studies is difficult
because tho range of hydrologic conditions examined
and tile meanings of "wetter" md "'drier"
oftmn vary widely Further, tree density is influenced
by tmth stand ago and stand origin (Rraiewa
1983). ?Ille ability of red maple to dominate sites
that, mnge widely in wet,nc~s itself suggests that,
carlee e~tablisff~d, the trees adapt well fa the prev~ilrtlg
tiydrcrlogic regime and th:tt, unusually low
dr~-lait,y or basrrl arcsiz can bc expect.ed to occur only
where sitp wctxless ~ XCOO~W thi: spi*cies' t,oleranc
lcvei.
I-ts*lntIvc al_tt~nrlnltce ntld lion~;tu.q of shrubs
hrtvt bsoxk iihuwrl 14 iricri?i~s~ wit,h wetlleas in
rxonflc~)d~rlai~r red nri~ple swurnys (Ehrcrrfcld and
Gtilick 1989; Lowry 1084; Swift et a1. 1984; Paratlemy
arrd Fahcy 1986). In lthode Island, Lowry
folitrld that both ~lcsxlsity and perce~;?.it,agc cover of
strm-labs were greakst ~t ita as with the highest
nlcexx water l~vels, but he noted that. these sites
rtlsr, hixd tha lowent txcw canopy c30vr;r, the most
i,mranr~r~rc~ci xllicrort*licf, nnd the highest ground-
WH~&T p11. j\. sf.rong rcfnt,io~;?.i bctwccn wrttsr rcgirne
and tbn ~Lructure of troth tliti woody ul~ci~rstory trierce 1981; Tiner 1985) or in oxbows or on floodaxtd
the grt>tit~tX vqc~tation layer wm obscrvcd by
fwati~y and fi'tklley (1986) in a New York mixed
carlifer hwrtiwood swamp. In severely flooded and
nmeslterratdy floacic;d areas of the swwnp, woody
rzadcrstory cica~.rsitieas were 18,M6 and 10,881
sf~*rsts//kn, ms~rcct ivtaly, while values for seeps and
moderatc3Iy dry areas were 7,429 and
8,9:5G stn*mJX~n. The perccntngc. cover of woody
seedlings, prijtlirroicts, i\lld blyupl~ytes was found
conducted in southern New England and New
ta vary e3i&-;?.iifionrli,ly aiuorlg six gwoun(I v~~getatiorl York.
asaociatiorxs 13s well. Sedges and rnosscs wcrc
mosL abundant in those red maple cornnxunities Hydrologic Variation Among Swamp
wikh the highest ~a-rean water levels daring the Cammunitios
growing season. 12c*rcentnge cover of woody seed- Damn~an and Kershner (1977) identified soil
lings was in a msderabfy wet red maple
comnunity th~t received large inflow of nutrientrich
surface Water fmm a newby creek during the
spring.
%search in red maple swmnps in southern
New Jersey (Ehrenfeld and Gulick 1981; Ehren-
feid 1986) reaffirms the conelusiom drawn in
glaciated areas of the Northeast. In two separate
studies, shrub density and biomass were much
higher in wet hardwood swamps than in dry hardwood
swamps. While the biomass of herbs was
small to negligible at these sites, its relative eontribution
to total biomass was much greater at the
wetter sites; herb biomass totaled 195 kg/ha in the
wet swamps, but only 53 kfia in the dry swamps.
If the influence of hydrology on vegetation structure
is to be further elucidated, however, detailed
measurements of standard hydrologic parameters
over several years will be required.
Influence on Floristic Composition
The influence of water regime or soil moisture
on species composition and distribution in wetland
forests has been most clearly demonstrated
in floodplain communities. In the bottomland
hmdwood forests of the southern United States,
which often include a red maple component, plant
community composition has been shown to be a
function of the timing, frequency, and duration of
flooding or of anaerobic soil conditions ('Monk
1%; Brown et al. 1979; Huffman and Forsythe
1981; Conner and Day 1982; Parsons and Ware
1982). A strong relation between species distribution
and hydrologic regime has been shown on
northeastern floodplains as well. In this region,
red maple generally occurs in alluvial basins on
the inncr floodplain (Buell and Wiskndahl 1955;
plain terraces (Pierce 1981; Holland and Burk
1984; Metzler and Damman 1985) where the forest
is less frequently flooded by river waters and
the soil is less well drained after floods subside
than on the outer floodplain. Information on relationships
between water regime and the floristics
of nonfloodplain red maple swamps in the glaciated
Northeast comes primarily from research
n~oisLure regime as a key determinant of floristic
variation in western Connecticut forests located
over till and gneissic bedrock. They described
three red maple swamp communities in that region
and suggested that the floristic differences
anxong those communities were caused by differ-