Assessment of Wetlands Reserve Program restoration efforts as measured by occupancy of amphibian metamorphs

Transcription

1 Assessment of Wetlands Reserve Program restoration efforts as measured by occupancy of amphibian metamorphs Doreen Mengel Department of Fisheries and Wildlife Sciences University of Missouri Columbia, MO and David L. Galat U. S. Geological Survey Cooperative Fish and Wildlife Research Unit University of Missouri Columbia, MO

2 EXTINCTION CRISIS FOR AMPHIBIANS Frogs, toads and other species dying off -- new fungus magnifies environmental problems David Perlman, Chronicle Science Editor Friday, July 7, 2006 Dead frogs linked to global warming; Amphibians under worldwide threat Climate change, fungal disease threaten frogs Tue Oct 24, :23pm ET Experts develop global action plan to save amphibians facing extinction

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6 Reasons for Amphibian Declines Habitat alteration and destruction Disease and pathogens Global climate change Invasive species Chemical contamination Commercial trade

7 Wetland-, or pond-, breeding amphibians: require lentic habitat for egg-laying and larval development.

8 Complex Life Cycle Terrestrial Phase - Adults Aquatic Phase - Larvae

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11 % loss of wetlands statewide MN MI WI OH IA IL IN MO KY AR TN AL MS LA State

12 Wetlands Reserve Program A voluntary USDA program designed to convert marginal, flood-prone agricultural lands back into wetlands.

13 Wetlands Reserve Program Program Emphasis Protect, restore, and enhance the functions and values of wetland ecosystems to attain: Habitat for migratory birds and wetland-dependent dependent wildlife Water quality Attenuation of water flows during flooding Recharge of ground water Protection and enhancement of open space Protection of native flora and fauna Contribution to educational and scientific scholarship

14 Wetlands Reserve Program Available in Missouri in One of 9 states participating in pilot program. First year, Natural Resources Conservation Service (NRCS) 19 landowner contracts to restore 1,696 acres. To date 772 contracts, pending or completed, to restore 116,094.

15 Wetlands Reserve Program Three Criteria for Emphasis Areas Historic presence of wetlands Identified in 1989 MDC Wetland Management Plan and referenced in North American Wetland Management Plan Areas of concentrated, present-day waterfowl use

16 Wetlands Reserve Program Lower Grand River basin one of 3 emphasis areas Flood attenuation Water quality improvement Wetland habitat for migratory wildlife

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19 Evolution of Thought Process

20 Walk-away

21 Maximize Hydrology

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24 Naturalistic

25 Floodway Setback levee

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27 To what extent are management objectives being met?

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29 Need a reference condition

30 Goal of WRP is to restore the hydrological and biological characteristics of wetlands Amphibians can serve as surrogate for reference condition. Because amphibians distribute themselves across hydrological gradient, representation by all local amphibian populations on WRP restored wetlands would infer program is meeting its goal. Success = metamorphs as they represent recruitment and recruitment = species success at population level.

31 Natural Hydroperiods High probability of Survival to Metamorphosis Balanced Predator populations Wetland Low levels of contaminants High density and diversity of suitable wetland habitats Natural habitat between wetlands High probability of successful dispersal and recolonization Terrestrial Natural Vegetation cover Undisturbed terrestrial habitats Low exposure to chemical compounds Maintenance of Viable Populations and Regional Diversity of Amphibians High probability of Adult Survival modified from Mushet et al. 2006

32 External Drivers Embrace uncertainty (Graphic after Nichols and Runge - April 2005) Environmental Variation Condition Today Management Actions Decision Model of the system Partial Control Structural uncertainty Condition Tomorrow Partial Observability Observed System State

33 External Drivers Embrace uncertainty (Graphic after Nichols and Runge - April 2005) Environmental Variation Condition Today Management Actions Partial Control Structural uncertainty Decision Model of the system Condition Tomorrow Partial Observability Observed System State

34 Successful Wetland Restoration High Amphibian species richness and abundance associated with WRP tracts

35 Species richness generally estimated with presence absence inventories Absence: ambiguous state as a species not seen may be present but undetected. Viewed as somewhat uninformative if not paired with abundance.

36 Abundance difficult to measure particularly with species such as amphibians that exhibit high variation in numbers. Time and resources usually limited.

37 Occupancy modeling offers alternative to abundance estimates. Occupancy: proportion of suitable habitat within a defined area occupied by the target species. Shifts focus from how many at various locations to what fraction of the landscape does the species inhabit.

38 MacKenzie et al. (2002) single-season, single species occupancy model that allows estimation of proportion of area occupied as a function of measured covariates while accounting for imperfect detection.

39 Research goal Assess WRP restoration efforts by determining if restored wetlands on WRP tracts within the lower Grand River basin provide recruitment habitat for local amphibian populations.

40 Objective Determine relative species richness of the metamorphic amphibian assemblage occurring on walk-away, maximize hydrology, and naturalistic management strategies applied on WRP easement tracts within the lower Grand River basin as a function of regional-scale, site-scale, and landscape-scale covariates.

41 Regional Scale Covariates Management strategy (walk-away, max hydr, naturalistic) Tract size Site Scale Covariates Permanency of restored wetland Type and proportion of restored wetlands Amphibian species richness associated with WRP tracts Pred aquatic inverts Presence of fish Littoral zone Anthropomorphic influences (levees, borrows, roads) Landscape Covariates Other wetlands Isolation Terrestrial habitats Vegetation

42 Regional Scale Covariates Management strategy (walk-away, max hydr, naturalistic) Tract size Site Scale Covariates Permanency of restored wetland Type and proportion of restored wetlands Amphibian species richness associated with WRP tracts Pred aquatic inverts Presence of fish Littoral zone Anthropomorphic influences (levees, borrows, roads) Landscape Covariates Other wetlands Isolation Terrestrial habitats Vegetation

43 Regional Scale Covariates Management strategy (walk-away, max hydr, naturalistic) Tract size Site Scale Covariates Permanency of restored wetland Type and proportion of restored wetlands Amphibian species richness associated with WRP tracts Pred aquatic inverts Presence of fish Littoral zone Anthropomorphic influences (levees, borrows, roads) Landscape Covariates Other wetlands Isolation Terrestrial habitats Vegetation

44 108 WRP tracts included in sample

45 Actual Number of Tracts Sampled Included: 13 Walk-aways 18 Maximize Hydrology 19 Naturalistics Total of 50 tracts

46 Study Design Season: based on breeding chronology of amphibian assemblage within Lower Grand River basin. Three sampling periods: 1 March 15 April, 1 May 15 June, 1 July 15 August.

47 Study Design Season: based on breeding chronology of amphibian assemblage within Lower Grand River basin. Three sampling periods: 1 March 15 April, 1 May 15 June, 1 July 15 August. Actual sampling periods: 8 March 5 May, 14 May 10 July, 23 July? September.

48 Amphibian Sampling Design Sample unit: 50 m X 50 m block or 2500 m 2 randomly selected 9 11 blocks per tract

49 Amphibian Sampling Design Sampling methods: Follow guidelines provided by Heyer et al. (1994) and Olsen et al. (1997) Three methods: Aquatic funnel trap surveys Visual encounter surveys Dip-net surveys

50 Amphibian Sampling Design Sampling methods: Aquatic funnel trap surveys each block received 9-11 traps all individuals captured were counted; included amphibians, reptiles, aquatic invertebrates, and fish

51 Amphibian Sampling Design Sampling methods: Visual encounter surveys walk along waterline and search for evidence of amphibians Adults, juveniles, egg masses, tadpoles, metamorphs.

52 Amphibian Sampling Design Sampling methods: Dip-net surveys Survey each habitat proportional to its representation. More likely to provide information on larval salamanders and anurans than VES.

53 Regional Species Pool: 16 species Central newt (Notophthalmus viridescens) Plains spadefoot toad (Spea bombifrons) Spotted salamander (Ambystoma maculatum) Small-mouthed salamander (A. texamum) E. tiger salamander (A. tigirnum) American toad (Bufo americanus) Woodhouse s toad (B. woodhouseii) Blanchard s cricket frog (Acris crepitans) Gray treefrogs (Hyla chrysoscelis-versicolor) Northern spring peeper (Pseudacris crucifer) Western chorus frog (P. triseriata) Great Plains narrow-mouthed toad (Gastrophryne olivacea) Northern crayfish frog (Rana areolata) Plains leopard frog (R. blairi) Bullfrog (R. catesbeiana) Green frog (R. clamitans) Southern leopard frog (R. spenocephala) Wood frog (R. sylvatica) Actual Number of Species Sampled: 11

54 Expected Benefits Agencies required to quantify effects of conservation practices to ensure continued program funding. Amphibians provide means to quantify WRP s goal of achieving the greatest wetland functions and values, along with optimum wildlife habitat, on every acre enrolled in the program.

55 Expected Benefits Decision-making process- what to monitor, when, level of effort Potential resources: landowners, resource managers, local school groups

56 Natural Hydroperiods High probability of Survival to Metamorphosis Balanced Predator populations Wetland Low levels of contaminants High density and diversity of suitable wetland habitats Natural habitat between wetlands High probability of successful dispersal and recolonization Terrestrial Within tract scale Natural Vegetation cover Undisturbed terrestrial habitats Low exposure to chemical compounds Maintenance of Viable Populations and Regional Diversity of Amphibians High probability of Adult Survival modified from Mushet et al. 2006

57 Natural Hydroperiods High probability of Survival to Metamorphosis Balanced Predator populations Wetland Low levels of contaminants High density and diversity of suitable wetland habitats Natural habitat between wetlands High probability of successful dispersal and recolonization Terrestrial Regional scale Natural Vegetation cover Undisturbed terrestrial habitats Low exposure to chemical compounds Maintenance of Viable Populations and Regional Diversity of Amphibians High probability of Adult Survival modified from Mushet et al. 2006

58 Natural Hydroperiods High probability of Survival to Metamorphosis Balanced Predator populations Wetland Low levels of contaminants High density and diversity of suitable wetland habitats Natural habitat between wetlands High probability of successful dispersal and recolonization Terrestrial Landscape scale Natural Vegetation cover Undisturbed terrestrial habitats Low exposure to chemical compounds Maintenance of Viable Populations and Regional Diversity of Amphibians High probability of Adult Survival modified from Mushet et al. 2006

59 External Drivers Embrace uncertainty (Graphic after Nichols and Runge - April 2005) Environmental Variation Condition Today Management Actions Decision Model of the system Partial Control Structural uncertainty Reduced uncertainty More informed future decisions Condition Tomorrow Partial Observability Observed System State

60 Acknowledgments Missouri Department of Conservation Natural Resources Conservation Service- CEAP Committee Members: Raymond D. Semlitsch Joshua J. Millspaugh Field Technicians: -Shauna Marquardt -Richard Cooper -Amber Tetzner -Katie Bond

61 Questions?