Watershed Conservation Plan - Destination Erie

6.3.4 Predicted Effects of Climate Change on Forests
Predictions of the effect of modified temperature and rainfall in the Mid-Atlantic region of the
United States include possible major changes in the mix of forest tree species (Subak 2000); in particular,
maple–beech–birch forests may decline and be replaced by oak–hickory forests. Subak (2000) suggests
that combined changes in climate and vegetation will negatively affect migratory bird habitats and
contribute to a general decline in bird community diversity in our region. The forecast for the Great Lakes
region (Sousounis and Glick 2000) similarly predicts that warmer summers may cause reduction or loss
of some conifer and broadleaf tree species in Great Lakes forests. Sousounis and Glick (2000) also
indicate that animal species dependent upon specific habitats (migratory wood warblers) may suffer
declines, especially in the upper Great Lakes states of Michigan, Wisconsin, Minnesota. Michigan and
Minnesota are expected to possibly lose more than 50% of their wood warbler species. Warmer and
wetter climate expected across the Great Lakes region, coupled with CO 2 enrichment, may lead to
increased yields of some crops through 2050, followed by declines from 2051 to 2100 in the southern
Great Lakes (Sousounis and Glick 2000). This report suggests (and the authors of this plan concur) that
research is needed on the ability of vegetation communities to respond to global warming, and how the
dynamic of land use and management will interact with climate change. Sousounis and Glick (2000)
specifically recommend that adaptive management strategies should be used with forestry and land
management, and that tree planting and crop operations should select plant varieties more adaptable to
our changing climate.
At least one authoritative research investigation has already been carried out to gauge which local
tree species will likely decline with continuing climate change, and which species are likely to increase.
Iverson and Prasad (1998) used geographic information systems (GIS) to combine predictions for future
temperature and precipitation (from several different global climate models) with county-specific Forest
Inventory Analysis (FIA) data and local soils, land use, and elevation data to evaluate potential population
shifts for 80 different tree species in the eastern United States. Their model provides specific predictions
of future changes in the distribution of tree species for over 2000 counties east of the 100th meridian,
including Erie and Crawford Counties.
Iverson and Prasad's (1998) models predicts that many of the most important native tree species in
the study area will have their "ecological optima" shift at least 100 km (62 mi) to the north. Declines in
the study area are predicted for sugar maple, American beech, eastern hemlock, white pine, yellow birch,
red maple, and others. The models predict that several tree species that currently have a more southern
distribution, such as sweetgum (Liquidambar styraciflua) and chinkapin oak (Quercus muehlenbergii),
will shift northward into the greater study area (Iverson and Prasad 1998). One of the more disturbing
implications of these predictions is the likely impact of diminished numbers of hemlock and white pine
on the study area's coniferous and mixed forests, which have already been reduced by selective harvesting
and are critically important for wildlife habitat (PGC 2005) and water-quality protection.
7 RECREATIONAL RESOURCES AND PUBLIC INTERACTION WITH THE PENNSYLVANIA
LAKE ERIE WATERSHED
7.1. Recognized Recreational Resources
As noted above in this document (see chapter 1), surveys of the study area's residents conducted by
LERC in 2002 and 2003 as part of the present project indicate a general satisfaction with the region's
many and varied recreational opportunities. This speaks well of the accessibility and quality of the study
area's waters and related land-based resources, but also underscores the importance that these natural
resources be protected from unsustainable development and the pollution that accompanies it. Responses
made by study area residents surveyed in 2003 regarding outdoor recreational interests are graphically
represented in Figure 7.1. Picnicking (92%), motor boating (88%), swimming (87%), and fishing (86%)
are the activities showing the highest satisfaction ratings among those surveyed, closely followed by
non-motor boating, hunting, bicycling, and hiking in equal percentages (85%).
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