HyperNiche for Windows
98, 00,
ME, NT, XP, and Vista
Multiplicative Habitat Modeling
Version 1
To order: In Canada or USA call 1-800-690-4499 or Order
Online or Fax/Mail |
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HyperNiche is designed to be user-friendly software for
nonparametric regression. Our primary purpose is to provide a flexible tool for
multiplicative habitat modeling habitat models where the predictors are combined
multiplicatively rather than additively. We believe this is the most flexible,
powerful approach to habitat modeling. For in-depth explaination see Why NPMR?
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HyperNiche has many
potential uses:
- Build habitat models for species presence-absence (estimate
likelihood of occurrence in relation to multiple habitat parameters or other predictors).
- Build habitat models for species abundance (estimate abundance in
relation to predictors).
- Estimate physiological response surfaces in relation to 1, 2, or
more environmental parameters. Open your physiological variables as the response
matrix and your environmental variables as the predictor matrix.
- Build empirical models of species diversity in relation to
multiple predictors. Place your diversity measures (calculated with PC-ORD or a spreadsheet) in the response matrix.
- Relate community ordination scores to multiple environmental
variables. Save your ordination scores in a spreadsheet, then open this as the
response matrix and your environmental variables as the predictors.
- Optimize sample stratification choose combinations of
variable to maximize differences in a response variable among strata. Place
potential stratifying variables in the predictor matrix, then conduct a free search to
find the best combination of variables for predicting the response.
- Build multiple regression models for any nonlinear response to
multiple interacting factors.
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Simple, ecologically reasonable response surfaces pose difficult challenges to
traditional habitat modeling tools. HyperNiche
provides tools that easily find complex response surfaces, such as this hump that combines
sigmoid and Gaussian curves. |
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Comparison of NPMR in HyperNiche with other
methods of habitat modeling
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Comparison of GAM or GAMs (Generalized additive models) and
NPMR:
- GAMs and NPMR share the use of smoothing functions. Individual terms are
combined additively in GAMs and multiplicatively in NPMR.
- GAMs model interactions by adding specific terms, while they are modeled
automatically with a multiplicative kernel function in NPMR.
- Commercial software for GAMs is more expensive and harder to use than
NPMR in HyperNiche.
- GAMs have no theoretical basis for additive terms in controlling species
response functions, while NPMR has an explicit theoretical and biological foundation as a
statistical representation of Shelfords Law of Tolerance.
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Comparison of logistic regression and NPMR:
- In logistic regression (a form of generalized linear model, GLM) the
analyst must specify in advance the form of the response function for each predictor and
their interactions (e.g. sigmoid, hump-shaped, linear), even when the analyst has no
theoretical basis for choosing one response type over another, while NPMR is open to any
form of response function.
- Interactions must be modeled explicitly with logistic regression, by
adding specific terms, while they are modeled automatically in NPMR.
- Commercial software for logistic regression is more expensive and harder
to use than NPMR in HyperNiche.
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Comparison of MARS (Multivariate adaptive regression splines)
and NPMR:
- MARS fits separate splines to different intervals of the predictors,
while NPMR applies a multidimensional kernel smoother.
- Both MARS and NPMR can fit response surfaces that differ fundamentally in
shape in different parts of the surface.
- Both MARS and NPMR seek the best model by a numerically intensive and
exhaustive search through the domain of possible models.
- Both MARS and NPMR are well suited to modeling interactions. NPMR does so
automatically, while MARS users request consideration of interactions up to a specified
level.
- Commercial software for GAMs is more expensive and harder to use than
NPMR in HyperNiche.
- MARS has no theoretical basis in the biology of species response to
habitat factors, while NPMR has an explicit theoretical and biological foundation as a
statistical representation of Shelfords Law of Tolerance.
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