In situ Genetic Resources
2. Presentation and organization
About BEC (Biogeoclimatic Ecosystem Classification)
In order to evaluate the current degree of
protection and the need for additional gene conservation activities, good census
information is needed on population sizes for species of concern in currently
protected in situ reserves. We have completed an analysis on in situ conservation
in BC for all 50 tree species. This has been conducted by combining data on species
coverage for tens of thousands of botanical plots in the province with the distribution
of biogeoclimatic ecological classification (BEC) units using geographic information
systems and spatial analysis. This information is being used to determine: 1)
where additional information is needed (e.g. genetic structure and degree of population
differentiation for minor angiosperm and conifer tree species not previously investigated);
and 2) where additional in situ protection needed.
Presentation and organization of material
this section we present climate analysis results and climate data generated for
the biogeoclimatic zones and subzones of BC.
cataloguing information for species composition, and protected areas and land
use summaries presented here are organized by biogeoclimatic zone. For each zone
there is brief description of the general geographic location and climate. Photographs
from some of the common ecosystems and landscapes of the zone are posted and can
be explored using 3D imaging software.Species composition and the results from
a gap and threat analysis (Protected Area status and land use statistics) are
summarized at the zone level and links are provided for the same information compiled
at the subzone/variant level. A similar analysis has been performed on the basis
of seed planning units instead of BEC units. The results are not posted here but
can be found in Hamann et. al. 2004.
For each of BC's major tree species we have
compiled species summaries which include information on basic life history, ecology,
uses, distribution, reproduction, demographics, ex situ collections, genetic
structure, and resource management and seed transfer. In these summaries in
situ protection is calculated by BEC zone. Estimates of in situ protection
by Protected Area can be found in Hamann
et. al. 2005.
Hamann, A., Smets, P., Aitken, S. N. and Yanchuk, A. D. 2005.
ecogeographic framework for in situ conservation of forest trees
British Columbia. Can. J. For. Res. 35:2553-2561.
"Supplementary Data" for this publication (posted on the CFCG
website: in situ
Hamann, A., S. N. Aitken, A. D. Yanchuk. 2004. Cataloguing
protection of genetic resources for major commercial forest
British Columbia. Forest Ecology and Management 197: 295-305. "Extended
Manuscript and Data" for this publication (PDF
A Brief History
The BEC classification system was
developed by V.J. Krajina and his students in the 1960's and the 1970's. It was
adopted by the BC Ministry of Forests in 1976 and is widely used today for forest,
range and wildlife management. Refinement and expansion of the classification
system is ongoing and has been extended to seral ecosystems and non-forested ecosystems
such as wetlands and riparian areas, grasslands, alpine tundra and parkland. Here
we briefly describe some of the components as they relate to this project. For
more detailed information on the BEC system see the BC Ministry of Forest BEC
or Meidinger, D. and J. Pojar. 1991. Ecosystems of British Columbia. BC Ministry
of Forests, Victoria, BC. 330pp.
BEC is a hierarchical land classification system that groups ecosystems
using climate, soil and vegetation characterisitics. At the highest level, the
regional level, the province is divided into 14 zones. These zones are large geographic
areas with relatively uniform climate, i.e. similar regional or macroclimate.
Zones are usually named after one, two or three of the dominant climax species.
The names can also include another general distinguishing feature of the area
such as geographic location (interior, coastal,) or climate (subboreal, boreal,
montane). The names can be written in full or abbreviated: Coastal Western Hemlock
Zone or CWH zone.
Subzones and variants
are further divided into climatically distinct subzones. Subzones are named first
with a descriptor of relative precipitation (moisture) and then either relative
temperature or continentality. For example, subzones in the CWH zone range from
very dry maritime (CWHxm) to very wet hypermaritime (CWHvh). Subzones that have
considerable variation in climate are further divided into variants. Variants
are areas which are slightly drier, wetter, snowier, warmer, or colder than typical
but with a vegetation community that is not different enough to be considered
unique or distinct subzones. Numbers are used to identify variants, e.g. CWHvh1
climate class modifiers applied when naming subzones are relative. In most cases
they are inferred from the vegetation communities and not derived from actual
weather station data. With the availability of new climate data in GIS format
covering the entire province (elevation adjusted PRISM data) we have further quantified
the climatic differences between subzones/variants.
The variety of ecosystems that occur in each subzone or variant are described
using site classification. Site classification describes the pattern of ecosystems
across the landscape as it relates to specific site conditions (soil moisture
and nutrients). For the purpose of cataloguing in-situ conservation of
genetic resources of forest trees we perform most of the analysis at the zone
or subzone/variant level and do not use finer levels of classification. Generally,
species only show broad patterns of adaptation to macro-climatic conditions (zone
level of the BEC system). However, if a tree species exhibits a disjunct distribution
or other spatial patterns restricting geneflow, genetic differentiation may be
observed at the subzone/variant level.
some cases we use a simplified BEC system as a framework, where some small variants
and subzones are grouped if they are geographically adjacent, similar in species
composition, and similar in climatic conditions. Major genetic differentiation
within these combined landscape units would not be expected for any tree species.
This simplified system is used when evaluating (1) the protection status of tree
species, (2) land use patterns, (3) potential impact of climate change, and (4)
policy recommendations for landscape units. Subzones and variants were not combined
when calculating species composition statistics.