Geoscience Reference
In-Depth Information
Beech
AD 500
period
500 BC
Younger
Lime
period
3000 BC
Older
Lime
period
6000 BC
Hazel-
Pine
period
Birch-
Pine
period
Younger
Dryas
period
Allerød
period
Older
Dryas period
7000 BC
8300 BC
9000 BC
9700 BC
Figure 3-33.
Composite pollen diagram based on multiple sample sites in eastern Denmark, in which pollen
production of each species is taken into account. Black
=
trees and shrubs, dotted-gray
=
dwarf shrubs, lined
=
herbs
and grass. The periods shown on left side are developed throughout much of northern Europe and rel ect climate
change, soil development and plant migration. The Atlantic (gray) represents a climax forest dominated by elm,
linden (lime), oak, and other hardwood trees. The impact of early agriculture becomes marked in the Sub-boreal and
Sub-Atlantic periods. Dates are uncorrected radiocarbon ages. Adapted from Iversen (1973, Fig. 34). Copyright:
Geological Survey of Denmark and Greenland (GEUS).
include information on a given species' habitat,
distribution, range and health, reproductive and
breeding patterns.
To produce reliable results, monitoring
methods should employ scientii cally tested
survey sampling designs and follow set i eld
recording protocols (Fig. 3-35). New technolo-
gies such as GPS, GIS and remote sensing also
may be used to aid in capturing, analyzing and
publishing these data. Monitoring methods that
are easy to implement and quick to conduct,
include stakeholders, and are repeatable, scale
appropriate and sensitive to local geographic
contexts increase data reliability.
In addition to these elements, i eld survey
methods documenting fauna must be mindful of
seasonal or episodic patterns of occurrence with
birds, i sh, amphibians and other migrating
species. To increase chances of recording
species, careful attention must be given to the
activity patterns of target animals. Field visits
should be coordinated during peak activity time,
keeping in mind that some species may be more
active at night or during early morning and
evening hours. All the same, as Tyre et al. (2003)
suggested, several factors would inl uence the
ability to observe a species at any given time.
These include the spatial extent of the home
range of a species, prevailing climatic condi-
tions, the sample and survey design, and the
expertise of the surveyor to identify and record
species. Scientists conducting faunal surveys
especially guard against false absences or the
failure to detect a species, which can skew the
results of a study. Increasing the number of site
visits could increase the chances of spotting
target species.
One noteworthy example of a monitoring and
survey method is the North American Breeding
Bird Survey (BBS). Initiated in 1966, this annual
breeding-season bird survey uses government
and non-government experts and local
