risk assessment of batrachochytrium salamandrivorans introduction into the united states
TRANSCRIPT
RISK ASSESSMENT OF BATRACHOCHYTRIUM SALAMANDRIVORANS INTRODUCTION INTO THE UNITED STATES
William Sutton Dept. of Ag. and Env. Sciences Tennessee State University Nashville, TN 37209 [email protected]
Science 2015, Vol: 349(6247):481–482
• Worldwide, salamander diversity >670 species
• North America accounts for nearly 48% of global salamander diversity
• 9 of 10 salamander families reside in North America
• At least 4 families occur solely in NA (Amphiumidae, Dicamptodontidae, Rhyacotritonidae, Sirenidae)
• Majority of known diversity of family Plethodontidae occurs in North America
Bsal Risk Assessment Model Methods
• Unknowns - Climatic niche of Bsal in Asia and United States - Full suite of potential salamander hosts - Locations of infected animals in Bsal native range
• Known factors
- Three species identified as carriers of Bsal (based on Martel et al. 2014) a. Cynops pyrrhogaster (Japanese Newt) b. Cynops cyanurus (Chuxiong Fire-bellied Newt) c. Paramesotriton deloustali (Tam Dao Salamander) - Potential shipping ports where Bsal is most likely to be spread in the US
Photo: Bill Sutton Cynops pyrrhogaster
Cynops cyanurus
Paramesotriton deloustali
Bsal Risk Assessment Model Development • Climatic Niche Model development - Known occurrences of 3 carrier species in Asia (proxy) - 133 occurrences - Majority of occurrences C. pyrrhogaster - Six bioclimatic variables (www.worldclim.org)
• Random occurrences used to supplement dataset - Based on known natural history characteristics - C. cyanurus and P. deloustali
• Maxent v. 3.3 to estimate potential climatic niche - Correlative, presence-only modeling algorithm
Bsal Risk Assessment Model Methods
• Resulting “Asia” model projected onto NA climate conditions
• Map projection represents a logistic output of estimated suitability
Bsal Risk Assessment Model Methods
• Acquired range maps for ~300 salamanders in the United States
• Expert opinion used to derive and/or edit ranges for 11
species
• Maps were rasterized and summed to create additive species richness layer
Bsal Risk Assessment Model Methods
• Final Risk Assessment Model - Derived as the following equation - Relative Risk = SpRich * Log ClimSuit
Appalachia and Southeast US
• Highest taxonomic diversity • 7/10 Families
• Plethodontidae • Salamandridae
• Up to 29 co-occurring species
• Many endemic species • Includes Eastern Newt range
Photos by Henk Wallays and Todd Pierson
West Coast of the US
• Highest Bsal habitat suitability • 5/10 Families
• Salamandridae and Plethodontidae
• Up to 12 co-occurring species • Includes Rough-skinned newt range
Photos by Tiffany Yap, Harry Greene, Todd Pierson, and Sam Murray 1
5
Central Highlands of Mexico • Sierra Madre Occidental, Sierra
Madre Oriental, and Trans-Mexican Volcanic Belt
• Hotspots of tropical salamander diversity
• High endemism; high beta diversity
• Many are threatened or endangered
Photos by Abel Batista, Todd Pierson, Sean Rovito
Which NA Ports Pose Greatest Threats for Bsal Introduction?
Identification of At-Risk Ports:
• Shipments 2010 – 2014
• Native ranges in Asia
• Shipments through Asia
• 99% shipments from Asia
• 98% of shipments Asian species
• 91% of shipments contained C. pyrrhogaster, C. cyanurus, & P. deloustali
Take Home Messages • Preventative measures are much more effective than emergency
measures - Irreversible biological consequences may be avoided
• USFWS could place ban on salamander introductions until adequate
mgmt. efforts are in place
• Efforts are required to monitor zones of high Bsal vulnerability
• The pet trade industry MUST play a large role in this process for preventative measures to be effective