landscapes with long, wide corridors Desperately seekingstable 50-year-old Paul Beier and Andy Gregory, Northern Arizona University
Do conservation corridors really work? (“It depends.”) What are the traits of successful conservation corridors? Paul Beier and Andy Gregory, Northern Arizona University
For 10 years, I’ve been designing corridors for focal species so we can conserve them... A B … before we develop the rest of the matrix.
South Coast Missing Linkages: 11 designs 2002-2008 Over 240,000 acres conserved
Arizona Missing Linkages 16 Linkage Designs 2006-2008 are being implemented (e.g., these wildlife crossings near Tucson)
Bay Area Critical Linkages: 14 designs 2009-2012 California Desert Connectivity: 23 designs 2011-2012
I’ve helped develop 64 Linkage Designs since 2001 The good news: These plans are being implemented! Thescaryquestion: “Will thesecorridors work?”
Do conservation corridors work? Each corridor design is a prediction: These long swaths of land will support gene flow between the two wildland blocks even after the matrix land has been converted to uses incompatible with wildlife movement.
But… don’twealreadyknowthat corridors work? Gilbert-Norton et al. (2011. Conservation Biology 24:660-668) summarized 78 corridor experiments: Corridors increased movement between patches by 50% on average.
Conservation corridor Typical corridor study 1-ha clearcut patches connected by 150 x 25 m corridor within forest (Savannah River Ecology Lab) • length ½ to 100 km • width > 1 km • matrix: cities, farms • desired response: long-term gene flow; patch occupancy • length < 150 m • width < 100 m • matrix: natural land cover • measured response: animal movement Past research does not tell us whether conservation corridors work.
Let’s find & study 100 “de facto” conservation corridors – anywhere on Earth. Criteria: Cities, suburbs, row crops 1. Stable landscape for decades (long enough for landscape pattern to produce a genetic signal) >½ km • 2. Matrix is human-dominated non-habitat. • 3. Focal species: any flightless mammal, reptile, amphibian, or arthropod that avoids matrix. • 4. At least ½ km between patches • 5. At least one type of reference: • Isolated patches, or Sampling locale • Intact area as big as corridor plus linked patches
Horskins et al (2006): the corridor failed. Connected patches Isolated patches Genetic distance between patches connected by a corridor was high – just as high as between isolated patches. … and much higher than between sampling areas within intact habitat. Cities, suburbs, & row crops Genetic distance CP1 IP1 SL1 Samples in intact area >½ km CP2 IP2 SL2
Mech & Hallett (2001): the corridors worked - ? Isolated patches Connected patches Genetic distance Genetic distances between 3 pairs of patches connected by corridors were lower than between isolated patches. … but much higher than between sampling areas within intact habitat. Cities, suburbs, & row crops Samples in intact area CP1 IP1 SL1 >½ km CP2 IP2 SL2
Desperately seekingstable 50-year-old landscapes with long, wide corridors A large sample will show: Cities, suburbs, & row crops 1. That some corridors do promote gene flow at the same levels as intact landscapes, and other corridors fail. >½ km 2. Which factors are associated with corridors that work. n = 1 Landscapes = replicates
Desperately seekingstable 50-year-old landscapes with long, wide corridors Learn more or suggest landscapes at www.docorridorswork.org Cities, suburbs, & row crops $250 honorarium for sites we use A M Y Ask your friends to find us on Facebook. >½ km B N Z
Focal Species • Any species that uses the habitat patches and the corridor but not the matrix • Species with short generation times and smallish Ne are preferred
Current status & project update • WE STILL NEED >60 MORE SITES….. • WE ARE STILL DESPERATE • June 2011, project initiated 0, study sites • July 2011, Launched our website and sent out a mass email plea for site suggestions • September - November 2011, Second mass email and publication of plea for study sites in Frontiers, BES, and other professional organization blogs and news letters As of 19-January 2012: • Website has had >1,500 visits, from >80 countries • 38 landscapes meeting criteria (subject to ground-check): US, Germany, Netherlands, Poland, Uganda, India, Kenya, Ethiopia, South Africa, Costa Rica, Brazil, Argentina, & Sabah Borneo.
A corridor design is a prediction that “this land will support gene flow between the two wildlands evenafter the other matrix land has been converted to uses incompatible with wildlife movement.” If we want to test this prediction, we must study gene flow in landscapes where the corridors are of similar size as conservation corridors, and where the matrix has been converted. “This project is the most important thing that could be done in the study of corridors, and one of the top 3 most important things that can be done in all of conservation biology.” - Dr. Nick Haddad, NC State University