Ecohydrology: Understanding the Dynamic Relationship between Biota and Abiotic Environment

1. Ecohydrology Fall 2019 Matt Cohen SFRC

2. Introductions Name Department Title of your research (thesis, dissertation) Ecohydrology Ordination Applied Hydrology Ecology MC MC Theoretical

3. Course Goals • Study the dynamic and reciprocal interplay between biota and their abiotic environment (broadly construed “hydrology”) • Develop conceptualsynthesis skills by focusing a large topic area into a small space [paper] • Develop hypothesis and analysis skills by addressing a research question [project] • Develop teaching skills by guiding a group learning experience [discussion]

4. Defining and Defending the Term • “There are cracks in everything…that’s how the light gets in.” – Leonard Cohen • Reality is a continuum over space and (deep) time • Mantle-Soil-Water-Biota-Atmosphere-(Human) Continuum • Disciplines are “convenient” fictions • Information silos focus questions but limit them too. This creates “cracks” that require interdisciplinarity. • Disaggregation vs. aggregation of knowledge • Ecohydrology is the essential aggregation of physical and biological theory towards understanding patterns in nature • Ecohydrology: A science which seeks to describe hydrological mechanisms that underlie ecological pattern and processes Rodriguez-Iturbe (2000)

5. Ecologists have studied water effects on: Animal dispersal, habitat suitability and fecundity Plant ecophysiology Soil dynamics Population ecology and community dynamics Carbon fluxes Non-native plant invasion Cropping systems Hydrologists have studied vegetation effects on: Soil erosion and geomorphology Evaporation at land surface Infiltration and runoff dynamics Atmospheric boundary layer Albedo and radiation Soil moisture – rainfall feedback Climate change Channel hydraulics Is it new?

6. Is it general? • Plant-soil-water relations starkly different: • Wetland hydrology (peats, fens, bogs, marshes) • Artic hydrology (boreal forests, tundra) • Tropical hydrology (rain forests, mangrove swamps) • Arid hydrology (grasses-shrublands, succulents) • Mountain hydrology • The basis principle – that hydrology and ecology are best understood as reciprocal bodies of knowledge – IS general.

7. Is it practical? • Course emphasis on theory and methods • Recent examples of applicability: • Minimum flows and levels or e-flows (regulatory) • Restoration principles and targets • Definition of Waters of the US (connectivity) • Disturbance-hydrology feedbacks (Western USA) • Forest water yield (Evaristo and McDonnell vs. Kirchner et al.) • Nutrient enrichment in lakes vs. rivers

8. Administrative Debris • Instructor: Dr. Matt Cohen • mjc@ufl.edu • http://sfrc.ufl.edu/ecohydrology/FOR6564.html • 352-846-3490 • Office hours MF 10-12 (or by appointment) • Meeting times • Tuesday: 1:55-2:45 MCCBG108 • Thursday: 12:50-2:45 MCCBG108

9. More Debris • Recommended Text: • Hydroecology and Ecohydrology: Past, Present and Future. 2007. P.J. Wood, D.M. Hannah and J.P. Sadler (eds.) • Primary literature

10. Assignments • Lead class discussion – 25% • One student each week (except weeks 1 and 2) • Select 1 paper from instructor’s list (more next) • Everyone gets one week to read this; read it • Provide background, context, summary, critique • Bring additional literature where necessary • Synthesis paper – 35% • 15-20 page paper due October 3rd. • Topic area selected (with instructor) by Sept. 12th • Synthesis – pick a question with broad scope • A little relief: Ecological functions and autogenesis of wetland microtopography

11. Assignments • Group (n = 2-3) Project – 40% • Proposal due Oct. 12th • Small equipment/sample costs covered • Drafts due Nov. 21; Final due Dec. 5. • Potential subject areas: • Analysis of wetland controls on watershed DOC yield • Water yield responses following Hurricane Michael • Analysis of diurnal streamflow variation • Analysis of Thames River metabolism • Analysis of breaks in C-Q patterns for evidence of biotic retention • Analysis of spring river SAV patch vs. sediment

12. Homework Assignment • Identify three candidate papers for discussion • One in your area of expertise/focus • One in an area of (new) interest • One synthesis/vision paper • Send them to me by Thursday. A full list of papers from which you can choose your discussion lead will follow in ca. 1 week (with a calendar).

13. Sources of Primary Information • Key Journals • Ecohydrology • Water Resources Research • Ecology • Ecological Applications • Geophysical Research Letters • Hydrological Processes • Ecosystems • Hydrology and Earth System Sciences • Limnology and Oceanography • PNAS/Nature/Science/PLoS1 • Etc. …being out there.

14. Systems Thinking

15. - - + A Rat Infestation • Gainesville home built in 1928 • No rats when we moved in • Lived there for just under 2 years • “Massive” control efforts by the end • Owners of 2 large dogs • Exceedingly poor hunters • Neighborhood of cat owners • Every direction (E, W, N, S) had one or more felines • Drove the dogs crazy…ever-vigilant border patrols

16. Elements of Systems • Boundary (the yard) • Inputs and outputs (cats, dead rats) • Internal components (rats, dogs) • Interactions • Positive interactions (rats breeding) • Negative interactions (cats on rats, dogs on cats)

17. Why Systems? • Interactions create complexity • Emergent behavior • Water is “wet” • Traffic snarls (even without accidents) • The Rise of Fall of Pet Rocks • Thresholds (tipping points) exist • Predicting these is enormously important • Global climate change, business cycles, disease epidemics • Systems aren’t more complex than we think, they are more complex than we can think. • But…we have to try! $3.95 each (!)

18. Key Attributes of Systems I. • Mutual causality • Components affect each other, obscuring linear cause-effect • Popularity → sales → popularity • Poverty → soil erosion → poverty • Chicken → Egg → Chicken • Indirect effects • Component A exerts control over Component B via its action on Component C A B C A B

19. Aleutian Islands • Nutrients are essential for plant and animal production • Phosphorus (P) is often limiting nutrient • Essential for ribosomes and metabolism • Limited geologic source in the region • Amount of P controls the productivity of the ecosystem • Grassland production of Aleutian islands is P limited • Source of P is the guano of sea birds Abundant P Depleted P

20. Nitrogen and Sea Birds • Seabirds eat fish from the sea but poop on land • Major flow of P from sea to land that supports productive grasslands + Fish Marine Birds + Soil P Grassland Production +

21. Predator Control of Ecosystems Arctic Foxes • Introduce Arctic Foxes • Top-predator • Seabirds never had a terrestrial predator • Decimated the sea-bird populations - + Fish Marine Birds + Soil P Grassland Production + Roughly 3x more soil P AND biomass on fox-free islands than on fox-infested islands

22. Key Attributes of Systems II. • Consist of processes at different space/time scales • Fast and slow variables • Humans and viruses • Evolution and extinction • Systems are historically contingent • Deep dependence on what happened in the past • The Great Unfolding • Beta-max, Bacteria, Base 10 A B B A C

23. Fast & Slow:Time Lags in Complex Systems • Variables operating at different characteristic “speeds” interact • Those interactions are complex because they can be affected by delays • Sunburns (anticipating when to reapply) • Hangovers (anticipating when to say “no”) • This affects natural systems (predator-prey systems) AND economic and social systems (business cycles, shifts in behaviors)

24. Consider a Simple Ecosystem • One prey item (rabbits) that reproduce quickly in proportion to their numbers • One predator (foxes) that reproduce more slowly and eat rabbits in proportion the rabbit numbers • Complex dynamics Rabbits Foxes dR/dt = (b – p*F)*R dF/dt = (r*R - d)*F

25. Dependence on History: Algae, Nutrients, and Shallow Lakes • Shallow lakes (< 10 m deep) • Florida has thousands • Two alternative “states” • Rooted vegetation (macrophytes) • Algae • Shifts between the two occur catastrophically, and BOTH can occur under the same environmental conditions • Where you are depends on where you’ve been

26. Self-Reinforcing Feedbacks in Shallow Lakes • Rooted Plant State • Plants require clear water • Plants stabilize sediments • Stable sediments keep water P concentrations low AND limit stirring • Low P limits algae and high clarity favors rooted plants • Algae State • Algae makes ooze • Ooze is easily stirred up, making the water turbid and recycling P • More P makes algae grow faster AND sediments looser via loss of plants • Regime shifts due to combined effects: • Too much P (human pollution) • Disturbances (pollution affects vulnerability)

27. Environmental Change and Ecosystem “State” Shifts Typical Models of Nature Emerging Model of Many Complex Systems Scheffer et al. (2001) - Nature

28. Example – a hydrological system Slow Sand “Trickling” Filter Depth = D[L] Area = A [L2] Saturated hydraulic conductivity (Ksat) [L T-1] *Porosity = f [-] h2 D h1= 0

29. Example – a hydrological system Slow Sand “Trickling” Filter Depth = D[L] Area = A [L2] Saturated hydraulic conductivity (Ksat) [L T-1] If Qin = Qouth2= ? If Qin > Qouth2= ? If Qin < Qouth2= ? constant increases decreases h2 D h1= 0 How to describe this relationship?

30. Influence diagram – hydrological system Qout h2 A homogenous, first-order, linear, ordinary differential equation… + - + Qin h2

31. Example – an ecohydrological system? Biofilm (“Schmutzdecke”) – gelatinous biofilm of bacteria fungi protozoa rotifera and a range of aquatic insect larvae. Biofilm thickness B = f (d): Slow Sand “Trickling” Filter Depth = D[L] Area = A [L2] Saturated hydraulic conductivity (Ksat) [L T-1] d h2 D h1= 0

32. Example – an ecohydrological system? Hydraulic conductivity affected by biofilm thickness Ksat = f (B): Slow Sand “Trickling” Filter Depth = D[L] Area = A [L2] Saturated hydraulic conductivity (Ksat) [L T-1] d h2 D h1= 0

33. Influence diagram – ecohydrological system h2 Qout + Ksat + Qin - - Biofilm + h2 +/-

34. EcohydrologyExamples to Animate Systems Concepts

35. Okavango Delta

36. Okavango Watershed The Okavango river shared by Angola, Namibia and Botswana Endorheic system Delta 12,000 km2 wetland system in a semi-arid environment

37. The Okavango Delta

38. Water is NOT from Local Rainfall • Rain falls in Angolan highlands • Flows through semi-arid zone (losing stream) • Water is critically limiting resource • Namibia for supply and power • Angola for irrigation • Botswana for biota (incl. rich tourists)

39. Gumare fault Kunyere fault Thanalakane fault Gumare fault At the tail end of the East African Rift system

40. Flood Characteristics • Strictly seasonal rainfall over southern Africa – warm rainy summers, dry cool winters • flood-pulsed wetland, with an annual flood event • flooding asynchronous with rainy season

41. Biodiversity

42. High End…. To Shoot an Elephant or Lion: $75,000 for license, $50,000 for lodging, food and transport To shoot pictures: $500-1000 per person per night

43. Perennially flooded

44. Seasonally inundated floodplains

45. Drylands

46. Material inputs to the Delta • Sediment: ~1,700,000 tons/yr • Dissolved Salts: ~500,000 tons/yr • Dust deposition: ~250,000 tons/yr?

47. Example 1 - Ecological processes from sediment inputs • Channel “avulsion” Surface aggradation and isostatic adjustment

48. Mechanism Distributary channels in the Okavango Delta Carry (and drop) sediment and distribute water Channels constrained by a dense mesh of macrophytes (papyrus) Rapid aggradation such that channels are higher than surrounding marsh Lower velocity/impoundment Increasing plant colonization further accelerates aggradation process Catastrophic bank failure and new channel initiation along pre-existing hippo trails McCarthy et al. (1992)

50. Major Consequences Locally