Multi-Scaled Socio-Ecology of the Everglades FCE III Conceptual Framework

Transcription

1 FRESH WATER SUPPLY 1 Multi-Scaled Socio-Ecology of the Everglades FCE III Conceptual Framework Global Climate Change Regional Climate Modulation 2 B O Carbon Cycle P T Organic Matter EXTERNAL DRIVERS LOCAL RESPONSES Global Socioeconomic Change Regional Water Management and Land Use Everglades Coastal Gradient 1 Geochemistry Carbon Cycle Consumers Primary Production Socio-ecological feedbacks South Florida Urban Gradient Resource Demand, Use, Stewardship and Management Decisions 1 MARINE WATER SUPPLY FCE III LTER Goals: 1 Water : How do water management decisions interact with climate change to determine freshwater distribution? 2 Carbon: How does the balance of fresh and marine water supplies regulate C uptake, storage, and fluxes by influencing water residence time, nutrient availability, and salinity? 3 Legacies: How does historic variability in the relative supply of fresh and marine water modify ecosystem sensitivity to further change? 4 Scenarios: What are alternative socio-ecological futures for South Florida under contrasting climate change and water management scenarios? Past 3 Present 4 Future

2 Party crashers: displaced marsh consumers regulate a prey subsidy to an estuarine consumer Ross Boucek & Jennifer Rehage Florida International University rbouc003@fiu.edu

3 Pulsed resource subsidies Resource pulse Instantaneous resource iincrease (Holt 2008) Subsidy Pulses across ecosystem b boundaries (Anderson et al. 2008) Yang et al Bird guano Mass emergences of aquatic insects Salmon in Pacific NW Seaweed deposits on beaches

4 Pulsed resource subsidies Subsidies can fuel almost all biological activity within (Polis et al. 2004; Spiller 2010) recipient ecosystems Marine to terrestrial

5 Information gap What regulates the flow of resources from one system to another?? Energy Energy? Paetzold et al. 2008

6 Consumers from donor communities important Deplete resources locally Nothing to transfer (Epichan et al. 2010) Track resources across boundaries Compete with recipient consumers Energy Energy Paetzold et al. 2008

7 In the Pacific Northwest Salmon migrate up river to spawn Subsidizing upstream communities River Ocean

8 Sea lions Track Salmon Up River River Ocean

9 Sealions reduce salmon subsidies by 65% River Ocean Recycling marine energy to the oceans Leaving hungry bears

10 Leading to Aggressive Management Naughton et. al. 2011

11 depth (cm) Everglades Ecotone: Wet season Marsh Estuary Marsh water level ( SH1; ) Year

12 depth (cm) Everglades Ecotone: Wet season Marsh Marsh Prey Estuary Marsh water level ( SH1; ) Year

13 depth (cm) Everglades Ecotone: Wet season Marsh Marsh Predators Estuary Marsh water level ( SH1; ) Year

14 depth (cm) Everglades Ecotone: Dry Season Marsh Marsh Predators Estuarine predators Estuary Marsh Prey Marsh water level ( SH1; ) Year

15 Research questions (1) Does marsh drying push freshwater prey into the estuary? (2) How do consumers respond to the pulse? (3) Are freshwater consumers reducing marsh subsidies for estuarine consumers?

16 Focal taxa: 2 freshwater + 1 estuarine consumer Gar, bass, bowfin and snook dominate Electrofishing (#/100m) Consumers show marked seasonality Largemouth Bass Wet Early Dry Late Dry Gar Bass Bowfin Snook Tarpon American eel Gray snapper Sheepshead Redfish Jack crevalle Ladyfish

17 Study system: ecotonal sites at ENP First and second order oligohaline estuarine creeks < 1.2 m depth < 10 PSU salinity 600 m

18 Hypotheses During drydown Prey abundance Post drydown Prey abundance Predator abundance Marsh prey consumption Diet segregation Predator condition Predator abundance Marsh prey consumption Diet segregation Predator condition

19 Marsh depth (cm) Tracking predator-prey abundance Data collection Continuously sampled 5 sites Nov 2010 to June 2011 Electrofishing Minnow traps * sampling events water level Statistics Compared time & species using GLMs Predator abundance * * * * * * * * * Prey abundance 4 functional groups -100 Sunfishes Cyprinodontoids Invertebrates Estuarine prey Sep Nov Jan Mar May Jul Sep 10 Nov 10 Jan 11 March 11 May 11 July 11 USGS station SH1

20 Stomach contents Data Collection Pulsed gastric lavage Statistics 100% effective in bass & snook (Adams et al Hartleb & Moring 1995) Compared effects of time & species using Scheirer-Ray-Hare test (Dytham 1999) Time partitioned into 4 hydrologic stages biomass of freshwater and estuarine prey consumed Numerical proportions of each prey functional group stomachs sampled Bass Bowfin Snook

21 # of prey per trap pair # of fish per 100 m Prey Predators Diet Fitness gains Electrofishing Sunfishes Estuarine prey Sunfishes Cyprinodontoids Minnow traps Cyprinodontoids Invertebrates Estuarine prey Invertebrates 40 0 Species, p =.001 Time, p =.001 Species x time, p =.001 Not sampled Nov. Dec. Jan. Feb. Early Mar. Late Mar. April May June Estuarine Prey

22 # of prey per trap pair # of fish per 100 m Marsh water depth (cm) Prey Predators Diet Fitness gains USGS station SH1 Electrofishing Minnow traps Not sampled Nov. Dec. Jan. Feb. Early Mar. Marsh water level Late Mar. Sunfishes Estuarine Prey Cyprinodontoids Invertebrates Estuarine Prey April May June Marsh drying Species, p =.001 Time, p =.001 Species x Time, p =.001

23 # of fish per 100 m Prey Predators Diet Fitness gains Pre drydown Early drydown Late drydown Post drydown Nov. Dec. Jan. Feb. Early Mar. Late Mar. April May June Species, p =.001 Time, p =.001 Species x Time, p =.001

24 Biomass (grams) consumed per 100 m Prey Predators Diet Fitness gains Freshwater prey Species, p <.001 Time, p <.001 Species x Time, p = Estuarine prey Pre drydown Early drydown Late drydown Post drydown Species, p <.001 Time, p =.2915 Species x Time, p =.965

25 Numerical Proportion Prey Predators Diet Fitness gains Species, p =.001 Time, p =.001 Species x Time, p =.01 Species, p =.001 Time p =.001 Species x Time, p =.47 Species, p =.001 Time p =.001 Species x Time, p =.85 Sunfishes Cyprinodontoids Invertebrates Pre drydown Early drydown Late drydown post drydown Dish = 10 cm

26 Condition Prey Predators Diet Fitness gains Pre drydown Early drydown * Late drydown * Post drydown * * * Nov. Dec. Jan. Feb. Early Mar. Late Mar. April May June Bass, p =.001 Snook, p =.001 Bowfin, p =.001

27 Summary of results During drydown Post drydown Prey abundance Prey abundance Predator abundance Predator abundance Marsh prey consumption Marsh prey consumption Diet segregation Diet segregation Predator condition Predator condition

28 Summary of results During drydown Post drydown Prey abundance Prey abundance Predator abundance Predator abundance Marsh prey consumption Marsh prey consumption Diet segregation Diet segregation Predator condition Predator condition

29 Summary of results During drydown Post drydown Prey abundance Prey abundance Predator abundance Predator abundance Marsh prey consumption Marsh prey consumption Diet segregation Diet segregation Predator condition Predator condition

30 Summary of results During Drydown Post Drydown Prey Abundance Prey Abundance Predator Abundance Predator Abundance Marsh prey consumption Marsh prey consumption Diet Segregation Diet Segregation

31 Summary of results During drydown Post drydown Prey abundance Prey abundance Predator abundance Predator abundance Marsh prey consumption Marsh prey consumption Diet segregation Diet segregation Predator condition Predator condition

32 Implications Marsh consumers regulate subsidy 36% Marsh consumers Estuarine consumers 59% 5%

33 Implications In a series of years with high rainfall Marsh consumers Estuarine consumers

34 Implications In a series of dry years Marsh consumers Estuarine consumers

35 Implications: Angler catches, Feb-June 40 snook bass Angler catch per day Recaptured bass!! Fished nearly every full moon of every month at the Rookery branch since 1982 Anglers in group wear counters to record bass and snook caught per day. Using similar lures since

36 Implications: Angler catches Feb-June Angler catch per day Bass years snook bass

37 Implications: Angler catches, Feb - June Angler catch per day Snook years snook bass

38 Everglades: World Class Snook Fishery Snook fishery maybe enhanced by subsidies 18,246 of anglers target snook at ENP /yr (Osborne 2006) Generating 4 million dollars per year (Fedler 2009 & Ault et al. 2010) Understanding and conserving snook High quality foraging opportunities important

39 Moving on to FCE III Trexler et al increased freshwater flow increases marsh fish production Proportion of subsidy to snook does not change, but the subsidy increases Sea level rise Snook prey availability Increased freshwater flow Large subsidy Small subsidy Magnitude of subsidy

40 Please Visit Poster #216 Acknowledgements USGS RECOVER FCE LTER FIU Rehage Lab Aaron Adams Craig Layman Michael Heithaus Amy Narducci Dave Rose and the southernmost bass anglers