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

Table 8.1. Emrnpks ofgmss loss rates for inland vegetated wetlands in thegtaciated Northeast. Losses
include changes from wetland to mnwetland, wetland to open watel; and wetland to farmlad
(including cranberry bog).
-- -- --- - Location Percent loss Study period Source
-- - - -
--
Pennsylvania
Northern Poconos 15 1950's - 70's Tiner and Finn (1986)
Northwestern region 5 1950's - 70's Tiner and Finn (1986)
New Jersey
Passaic County 15 1940-78 Tiner (1985)
Central Passaic River basin 50 1940-78 Tiner (1985)
Rhode Island
South Kingstown 1 1939-72 Golet and Parkhumt (1981)
Massachusetts
Bristol Countya 7 1951-71 Larson et al. (1980)
plymouth countyb 2 1977-86 Tiner and Zinni (1988)
15 communitiesC 4 1951-77 Organ (1983)
Connecticut
Central regiod 0.6 1980-86 Tiner et al. (1989)
-- ---
aOnly nonforested wetlands were included in this study.
b~tudy area included most of Plymouth County and small sections of Norfolk, Rristol, and Barnstable counties.
CCommunities were scattered across the state, and repwsented a wide range of physiographlr characteristics and population
densities.
d~tudy area included two-thirds of Hartford County and smaller portions of New IIaven, Tolland, and Middlesex counties.
Information on losses of forested wetlands is even
more scarce. Because forested wetlands predominate
throughout the Northeast, the loss of these
wetlands is assumed to be at least as great as that
for other types of inland wetlands. With minor
exceptions, such as timber harvesting, the causes
of forested wetland alteration also are similar to
those for other inland wetland types.
Rates of Wetland Loss
Loss rates reported for inland vegetated wetlands
in the glaciated Northeast vary widely with
geographic location and with the geographic scope
of individual studies (Table 8.1). The greatest
losses have occurred near major metropolitan areas.
For example, nearly 50% of the wetland area
in the central Passaic River basin of northern New
Jersey was destroyed between 1940 and 1978;
losses in Passaic County as a whole approached
15% during that period ('ISner 1985). The 4% loss
of pdustrine vegetated wetlandbetween 1951 and
1977 in 15 communities scattered across the state
of Massachusetts (Organ 1983) is probably an
average figure for southern New England over
that period. In Bristol County, Mass., however, 7%
of the inland nonforested wetlands were lost over
roughly the same period (1951-71). Recent studies
show that the rate of wetland conversion in
southeastern Massachusetts-and undoubtedly
in other areas of the Northeast as well-remains
significant even after implementation of state and
federal regulatory programs. Tiner and Zinni
(1988), for example, found that over 2% (513 ha) of
the palustrine vegetated wetland in the Plymouth
County area of Massachusetts was converted to
upland, to open water, or to managed cranberry bogs
between 1977 and 1986. More than 260 ha of forested
wetlands were lost during that 9-year period.
Principal Causes of Wetland Loss
Although documentation is lacking, conversion
of wetlands for agriculture, the construction of
impoundments for hydropower and water supply,
and the cutting of swamp timber for lumber, fence
posts, and fuelwood were probably the dominant
fom of inland wetland alteration in the Northeast
prior t.o the mid-18Ws. Since that time, m d
especially since World War 11, urbanization has
emerged as the predominant force impacting wetlands
in most parts of this region. The extent and
causes of wetland loss have been documented in
several areas of southern New England (Table 8.2).