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forest age associated with "checkerboard" ownership patterns in the West, then section
boundaries will not work, and you will need to start the grid at a random location.
As was mentioned above, managers can decide where to sample, but our
recommendations are generally to sample in cover types and areas which there is some
evidence of historical lynx occurrence. Maps of broad cover-types associated with
historic lynx occurrence are available for the contiguous US. These cover-type maps, or
local vegetation coverage, can serve as a guide for determining priority of survey efforts.
We would caution that, early in the process, deciding a priori that an area cannot support
lynx without detailed local knowledge, is not without risk. If grids are designed as a
representative sample of a particular cover type, sampling within this cover type
provides no information about any other cover type. There will always be this trade-off:
tight stratification rules will presumably increase the efficacy, but they limit the
inference. Additionally, this grid-based approach works best and is most efficient in
areas where cover types are reasonably contiguous.
Exactly how you resolve the relative importance of these two properties: efficacy vs
inference, and hence how you stratify your landscape prior to sampling, will largely be a
function of local knowledge, priorities, and vegetation patterns. Two examples may
provide insight into this process. In the Superior NF a question of primary importance
is: Do we have any resident populations of lynx? To answer this question, the Superior
will be looking to place grids in those areas where they have the most recent evidence of
lynx occurrence and where the habitat appears to be most suitable. In the Okanogan NF,
the presence of lynx in the area studied by Koehler and Brittell is not in question. The
Okanogan, therefore is placing grids in areas where they have some information that
lynx occur, and would like to gather more data concerning these lynx. They are not,
therefore, necessarily placing the surveys in the "best" areas, as is the Superior, but they
are still only surveying in-and-adjacent-to cool wet forest types.
