Methods for Defining and Identifying Critical Habitat for Rare

and Endangered Species

Jeremy VanDerWal and Lesley Lovett-DoustDept. of Biological Sciences,

University of Windsor

• Two main theories:– Metapopulation theory and Landscape

ecology– Assume landscape is binary…composed

of patch and matrix

• Metapopulation ecology– Framework for understanding population

dynamics in spatially structured landscapes– remains focused on species characteristics

and the patch– patches may vary in size, degree of isolation,

quality, etc.– often ignores the matrix

The Patch

Patch-based modeling

• Attempts to relate species characteristics to characteristics of the patch -- i.e. – species abundance with patch size, shape,

quality…– probability of extinction/recolonization with

patch size, isolation...

The Matrix

• Landscape ecology– summarizes effects of landscape composition

and configuration on ecological processes– landscapes can not be simply classified as

patch and matrix• Matrix is composed of patches which are more or

less similar to the focal patch

– the matrix matters -- i.e. influences dispersal

Patch/matrix-based modeling

• Relate species characteristics to characteristics of the patch AND the surrounding matrix -- i.e. – species abundance with patch size, shape,

quality…AND also surrounding landuses, soil types, etc.

– probability of extinction/recolonization with patch size, isolation…BUT with isolation influenced by the matrix

Opuntia humifusa Prickly Pear Cactus

• Species at Risk in Canada (COSEWIC)• only 2 populations located at Point

Pelee National Park and on Pelee Island

Rules:• Within:

– primary or secondary successional savannas

– perimeter of PPNP (cannot be in Lake Erie)

• At least:– 10m from beach– 68m from marsh*– 128m from pond*– 174m from wet meadow*

• Cannot be within:– forest– on a road or trail– park infrastructure areas

* except along east beach

The challenge

• Binary landscape – patch / matrix– perspective of the organism– define habitat … delineate patch

• Scale of influence of the matrix– different environmental factors may have

influence on a species at different scales

• Incorporating multiple species…

> 12,000 rare species locations

# rare species = 4

73

2

93

The Landscape

Landscape sub-sampling

Landscape sub-sampling

Landscape sub-sampling

Hybrid model

LandscapeEcology &

MetapopulationTheory

Additional considerations??

FOCUSsoftware

GARPsoftware

Acknowledgements:

• Lesley Lovett-Doust

• Jon Lovett-Doust• Jan Ciborowski• Phil Graniero• Helen Murphy• Jeff Holland• Fellow grad

students• AERC• NHIC• NSERC• OGS• My wife, Andrea,

• AND my endangered species