An Approach for the Assessment of Indirect Effects to Threatened and Endangered Species Exposed to Herbicides: Glufosinate Case Study

Transcription

1 An Approach for the Assessment of Indirect Effects to Threatened and Endangered Species Exposed to Herbicides: Glufosinate Case Study R. Scott Teed, Scientist, Intrinsik Environmental Sciences Inc. September 1 st, 2011

2 Co-Authors D.R.J. Moore, Intrinsik Environmental Sciences (US), Inc., New Gloucester, Maine, United States T. Hall, Bayer CropScience Inc., Research Triangle Park, North Carolina, United States S. Rodney, Intrinsik Environmental Sciences Inc., Ottawa, Ontario R.L. Breton, Intrinsik Environmental Sciences Inc., Ottawa, Ontario, Canada G.J. Sabbagh, Bayer CropScience Inc., Bayer Research Park, Stilwell, Kansas, United States

3 Overview ESA listed species Indirect effects Glufosinate case study Preliminary conclusions

4 ESA Listed Species 1379 ESA listed species (FWS website accessed Aug 22 nd, 2011) Under the ESA, EPA must consider listed species when registering a pesticide (a proposed action) Question: Are threatened or endangered species, and/or designated critical habitat likely exposed to direct or indirect effects of the action? If a listed species is not exposed, the action is unlikely to cause jeopardy to the species, or result in destruction or adverse modification of habitat under the ESA (NMFS, 2010) Minimal guidance to conduct effects determinations

5 Indirect Effects Herbicides may impact listed wildlife or aquatic animal species indirectly via many mechanisms, examples: Reduced primary productivity Altered structure and function of plant communities Reduced availability of favored dietary items Reduced availability of nesting habitat Current EPA guidance on assessing potential for indirect effects to listed species is limited, i.e., if no risk for direct effects to prey or habitat, then no concern for indirect effects EPA expected to produce more extensive guidance in the near future

6 Indirect Effects Framework for Evaluating Indirect Effects for Herbicides (Intrinsik, 2008) Tiered approach o o o o Tier 1 Screening-Level ERA Tier 2 Refined ERA Tier 3 Ecosystem Modeling Tier 4 Field, Microcosm, and Mesocosm Studies Listed wildlife species are typically generalists and are not dependent on only one or a few plant species. Therefore the protection goal for indirect effects is at the community level of organization The protection goal for direct effects to listed species is at the individual level of organization

7 Glufosinate Registered in 2000 Uses Pre-plant and post-emergent control of broadleaf, biennial and perennial weeds and grasses Crops: Apples, berries, canola, corn, cotton, currants, grapes, grass grown for seed, potatoes, rice soybeans, sugar beets, tree nuts Non-Crops: Golf course turf, ornamentals, lawns, general weed control

8 Fate of Glufosinate Water - Low persistence (T d) Soil - Medium to low mobility in loamy and clay soils, high mobility in sandy soil, low persistence (<23 d) Air - Not volatile Biota - No bioconcentration (fish), rapidly excreted Dissipation T days on terrestrial plants

9 National Endangered Species Assessment # Species Amaranth seabeach Paul Kelly, EPA Salt marsh harvest mouse

10 Case Study Use Pattern Application Rate (lbs ai/acre) Number of Applications/ Retreatment Interval Application Method Tree nuts, vines, apples / 10 d Ground Cotton / 10 d Aerial Where are apples and cotton grown, by county? What listed mammalian species co-occur with these use patterns and how do we establish a distance beyond which their food availability and habitat are not at risk?

11 County Co-Occurrence Tools FESTF NatureServ Multi Jurisdictional Database (MJD) FESTF Information Management System (IMS) Contain data on the locations of listed species & crop locations (county level) Listed Species / County / Glufosinate Use Pattern

12 County Co-Occurrence Analysis Map: Apples & T&E species Co-occurrence by county: 73 listed mammal species in apple growing counties 49 listed mammal species in cotton growing counties Which of these species may be affected indirectly?

13 Spray Drift Analyses Groundspray (Apples) Wolf and Caldwell (2001), Saskatchewan, Canada 18 m boom at 60 cm height, XR8003 nozzles, 6 trials, windspeed ( km/h) Three replicate measurements of fall out drift at each setback considered (1 120 m from boom edge) Aerial (Cotton) Caldwell and Wolf (2004), Saskatchewan, Canada Fixed wing monoplane AT502, wingspan of 15.2 m Travel speed approximately 225 km/h, release height of 3 m, windspeed km/h Three trials with 3 rep measurements of fall out drift at each setback considered ( m from flight line)

14 Fallout Percentage of Applied (%) Fallout Percentage of Applied (%) Spray Drift Curves Groundspray Data (medium droplet size) Selected Worst Case Trial Data Three-Parameter Log Weibull Model E-05 1E-06 Aerial Drift Data (medium droplet size) Selected Worst-Case Trial Data Two-Parameter Weibull Model Distance from Flight Path (m) Distance from Application (m) Aerial drift data from Caldwell and Wolf (2004) (Cotton) Ground spray drift data from Wolf and Caldwell (2001) (Apples)

15 Exposure Analyses Drift curves used to estimate downwind deposition and establish distance Multiple applications were accounted for assuming a foliar dissipation half-life of 5.5 d The peak temporal residues at various setback distances would occur after the final application 20 parallel, non-overlapping, upwind passes assumed

16 Metrics for Effects to Available Food and Habitat Species Sensitivity Distribution (SSD) Generated using SSD Master (5 models) 6 GLP Tier II studies (oat, carrot, onion, soybean, cucumber, tomato, cabbage) EC25 (lbs/acre) for vegetative vigor Community-level endpoint

17 Proportion of Plant Species Affected SSD for Terrestrial Plants HC20 = 0.11 lbs/acre Onion Soybean Cucumber Oat Effects to community structure and function typically occur at HC20 and above Functional redundancy 0.4 Cabbage Probit/Normal CDF Model 0.2 Tomato 95% Fiducial Limits Carrot Dry Weight EC25 Estimates Application rate in lb a.i./a

18 Proximity Analysis Drift Curves + SSD = Refined Proximity Analysis FESTF Species occurrence / land cover proximity database Provides distances from species element occurrences (EO) to USGS land cover Also FESTF critical habitat proximity database not included in this analysis

19 Proximity Analysis Inclusion zone an offfield area used to identify species that require a more refined analysis for direct and/or indirect effects

20 Inclusion Zone for Apples - Ground 2 m, 0.11 lb a.i./a HC20 HC20 for effects to community of plants occurs 2 m downwind

21 Inclusion Zone for Cotton - Aerial 20 m, 0.11 lb a.i./a HC20 HC20 for plant community effects occurs 20 m downwind

22 Proximity Analysis Co-occurrence by county: USDA National Land Class Data: Class 82 with listed mammals 2 m proximity distance (HC20) Primarily large wide ranging species

23 Case Study Initial co-occurrence analysis found: Apples: 73 mammals Cotton: 49 mammals Refined proximity analysis results: Apples: 39 mammals Cotton: 20 mammals Science-based proximity exclusion for indirect effects to 34 and 29 species associated with apples and cotton, respectively Additional exclusions or protections? (e.g., biological - diet) Remaining species still to be evaluated for indirect effects

24 Possible Future Analyses For highly mobile species (e.g., bears, cats) Determine proportion of their habitat in the field and inclusion zone Calculate proportion of exposed habitat vs foraging range Determine risk Obligate vs non-obligate species Karner Blue Butterfly / Wild Lupine Continue with Intrinsik guidance for indirect effects of herbicides (Intrinsik, 2008)

25 Conclusions Assessing risk of indirect effects of pesticides to ESA listed species in the United States is a huge undertaking Drift curves and other refined tools (SSDs) can be used to reduce the number of listed species requiring assessment and aid in the development of exclusions/protections Framework and guidance are required to ensure scientific defensibility and consistency

26 Thank You