Landscape Ecology 1222022 Landscape Ecology Matsinos 4 Landscape

Landscape Ecology 12/2/2022 Landscape Ecology Matsinos 4

Landscape ecology • Landscape ecology addresses the importance of spatial configuration for ecological processes. • Landscape ecology often focuses on spatial extents that are much larger than those traditionally studied in ecology. landscape ecology evolved from ecosystem ecology! 12/2/2022 Landscape Ecology Matsinos 5

Landscape processes • Spatial pattern and heterogeneity matter!! – Biogeochemical hot spots – Patch interactions 12/2/2022 Landscape Ecology Matsinos 6

Two aspects of spatial heterogeneity • Gradients or series of gradients which has gradual variation over space – No boundaries – No corridors – No patches • Mosaics where there are distinct boundaries 12/2/2022 Landscape Ecology Matsinos 7

Properties of patches • • • Size Shape Connectivity Boundaries Configuration 12/2/2022 Landscape Ecology Matsinos 8

Causes of heterogeneity • 1. State factors – Climatic gradients – Geologic boundaries – Topographic patterns 12/2/2022 Landscape Ecology Matsinos 9

Causes of heterogeneity • 1. State factors • 2. Historical legacies – Founder effects • species influence ecosystem processes • May reflect stochastic patterns of colonization – Historical land-use patterns 12/2/2022 Landscape Ecology Matsinos 10

Much of the Fairbanks region was clear-cut during the Gold Rush 12/2/2022 Landscape Ecology Matsinos 11

Causes of heterogeneity • 1. State factors • 2. Historical legacies • 3. Disturbance – – Disturbance can create patches of different ages Some disturbances are huge and/or infrequent Natural disturbances such as fire Human activity such as plowing fields and building roads. . Alter natural pattern of heterogeneity and patch dynamics 12/2/2022 Landscape Ecology Matsinos 12

Causes of heterogeneity • • 1. State factors 2. Historical legacies 3. Disturbance 4. Interactions among sources of heterogeneity 12/2/2022 Landscape Ecology Matsinos 13

Shifting steady-state mosaic • Disturbance creates patches of different ages • Landscape may be in steady state – Gap phase succession – Gopher patches in grassland • Every spot disturbed every 3 -5 yr – Age of rainforest trees only 80 -140 yr • Primary forest 1000 s of years old 12/2/2022 Landscape Ecology Matsinos 14

Steady-state landscape mosaic 12/2/2022 Landscape Ecology Matsinos 15 Gunderson and Holling 2002

Impact of disturbance depends on: Size Frequency 12/2/2022 Landscape Ecology Matsinos 16

Non-steady-state mosaics • Some disturbances are huge and/or infrequent • Create large patches of a single age – Yellowstone Park fires • Not in equilibrium with environment • Continuum between steady-state and non-steady-state mosaics 12/2/2022 Landscape Ecology Matsinos 17

Human disturbances • Alter natural pattern of heterogeneity and patch dynamics 12/2/2022 Landscape Ecology Matsinos 18

Shifting agriculture Steady-state mosaic with long rotations Non-steady-state mosaic with short rotations 12/2/2022 Landscape Ecology Matsinos 19

Interactions among sources of heterogeneity • Disturbance probability depends on – Landscape heterogeneity – Previous disturbance history • Negative feedbacks: reduced disturbance probability – Effect of fire on fire probability – Pathogen outbreaks: waves of disturbance 12/2/2022 Landscape Ecology Matsinos 20

Root pathogens initiate succession Increase nitrogen availability Reduce probability of pathogen outbreak 12/2/2022 Landscape Ecology Matsinos 21

Interactions among sources of heterogeneity • Disturbance probability depends on – Landscape heterogeneity – Previous disturbance history • Negative feedbacks: reduced disturbance probability • Positive feedback: increased disturbance probability – Effect of fire on insect outbreaks or logging » Fire increases probability of insects or logging » Makes landscape structure less predictable 12/2/2022 Landscape Ecology Matsinos 22

Interactions among sources of heterogeneity • Disturbance probability depends on – Landscape heterogeneity – Previous disturbance history – Human impacts • Roads increase probability of land-use change – Best single predictor of land-use change • Landscape heterogeneity influence human impact 12/2/2022 Landscape Ecology Matsinos 23

Topographic heterogeneity influences human impact Plains are converted to high-intensity agriculture Uplands are mosaic of subsistence farming Black: Natural Gray: Grazed White: Croplands Northern 12/2/2022 Argentina Landscape Ecology Matsinos 24

Mechanisms of Patch Interaction • Topography and land-water interactions – Gravitational redistribution • Landslides and erosion • Transfers to aquatic ecosystems – Influence of landscape pattern • Role of riparian zone 12/2/2022 Landscape Ecology Matsinos 25

Gravity determines direction of flow: donor vs. recipient Nature of patch determines importance in transfers Riparian zones are important filters configuration: between uplands and streams function: high plant uptake and denitrification 12/2/2022 Landscape Ecology Matsinos 26

Nitrogen inputs to major rivers determine nitrogen outputs Most nitrogen that enters a river is carried to ocean Little denitrification or other losses 12/2/2022 Landscape Ecology Matsinos 27

Mechanisms of Patch Interaction • Topographic and land-water interactions – Gravitational redistribution – Influence of landscape pattern – Properties of recipient ecosystems • Riparian ecosystems • Lakes on a topographic gradient 12/2/2022 Landscape Ecology Matsinos 28

Mechanisms of Patch Interaction • 1. Topographic and land-water interactions • 2. Atmospheric Transfers – Natural patterns • Transfers of gases (e. g. , NH 3) • Dust transfer 12/2/2022 Landscape Ecology Matsinos 29

Atmospheric transport Trace gases and dust produced in one place are transported and deposited downwind 12/2/2022 Landscape Ecology Matsinos 30

Mechanisms of Patch Interaction • 1. Topographic and land-water interactions • 2. Atmospheric Transfers – Natural patterns – Human impacts swamp natural transfers • Acid rain • Ammonia from fertilized fields and stockyards • Dust deposition from agricultural lands 12/2/2022 Landscape Ecology Matsinos 31

Acid rain Ecosystems are remarkably resilient to N deposition Eventually reach N saturation Begin to leak N and cations NPP declines Susceptible to other stresses 12/2/2022 Landscape Ecology Matsinos 32

Mechanisms of Patch Interaction • 1. Topographic and land-water interactions • 2. Atmospheric Transfers – Natural patterns – Human impacts swamp natural transfers • • 12/2/2022 Acid rain Ammonia from fertilized fields and stockyards Dust deposition from agricultural lands Altered energy exchange Landscape Ecology Matsinos 33

Clearing for agriculture in W. Australia altered climate 30% less ppt over farmlands 10% more ppt over heathlands Why? 12/2/2022 Landscape Ecology Matsinos 34 Photo: S. Chambers

Land clearing changes energy balance Higher albedo (less energy absorbed) More ET from irrigation (cools surface) Less sensible heat (less convective uplift) 12/2/2022 Landscape Ecology Matsinos 35

Mechanisms of Patch Interaction • 1. Topographic and land-water interactions • 2. Atmospheric Transfers • 3. Movements of plants and animals – Sheep carry nutrients to hilltops where they camp – Salmon carry marine nutrients to streams • Anadromous strategy is concentrated at high latitudes – 12/2/2022 People transport nutrients to fields and cities Landscape Ecology Matsinos 36

Horizontal flows produce patterns Transfer of nutrients by animals produces spatial patterns in nutrient pools and cycling rates and influences productivity. 12/2/2022 Landscape Ecology Matsinos 37

Mammalian herbivores use multiple patches in landscape Alter ecosystem structure Speed nutrient cycling Speed succession by removing early successional species ALDER : WILLOW RATIO 6 5 4 3 2 1 0 BROWSED 12/2/2022 Landscape Ecology Matsinos UNBROWSED 38

Mechanisms of Patch Interaction • • 1. Topographic and land-water interactions 2. Atmospheric Transfers 3. Movements of plants and animals 4. Disturbance spread 12/2/2022 Landscape Ecology Matsinos 39

Disturbance Dynamics CLIMATE Carbon Dynamics Lightning Thermokarst Harvest regime Fire regime Forest Dynamics Landscape structure Hydrologic regime 12/2/2022 Aquatic systems Landscape Ecology Matsinos 40

Fires occur frequently in the boreal forest 12/2/2022 Landscape Ecology Matsinos 41

Fire is a major agent of patch interactions in landscapes 12/2/2022 Landscape Ecology Matsinos 42

Fire size important • Distance to seed source (e. g. , white spruce) • Size of future fires • Carrying capacity for edge species (e. g. , deer) • Spread of pests and pathogens 12/2/2022 Landscape Ecology Matsinos 43

Human activities are now the largest cause of changes in landscape heterogeneity • Change natural vegetation from being the “matrix” to being the “patch” • Can’t understand landscape processes without considering human activities – People are integral components of regional systems 12/2/2022 Landscape Ecology Matsinos 44

Conversion of natural vegetation from “matrix” to “patch” Black patches are natural or semi-natural veg Gray patches have been modified by grazing White patches are agricultural fields Northern Argentina 12/2/2022 Landscape Ecology Matsinos 45

Human activities • Two general categories of land-use change – Extensification • Expansion of area used by people – Intensification • Increased inputs (subsidies) per unit area 12/2/2022 Landscape Ecology Matsinos 46

Extensification • Two categories of extensification – 1. Land-use conversion • Change in dominant plant functional type (PFT) • e. g. , forest to pasture; savanna to agriculture – 2. Land-use modification • Significant human impact without change in PFT • e. g. , low-intensity to high-intensity agriculture; cattle grazing on savannas 12/2/2022 Landscape Ecology Matsinos 47

Extensification • 1. Land-use conversion – Deforestation is widespread in tropics • Most primary tropical forests (largest biome on Earth) will disappear in your lifetime • Also occurs in boreal Canada and Russia (second largest biome on Earth) – Reforestation in temperate zone • Agricultural abandonment after earlier deforestation 12/2/2022 Landscape Ecology Matsinos 48

Extensification • 1. Land-use conversion – Deforestation is widespread in tropics – Reforestation in temperate zone – Conversion of savannas to agriculture • This has already happened • (Ukraine, midwestern U. S. , pampas) – Urbanization will continue to increase • Most people will live in cities – often in best agricultural lands 12/2/2022 Landscape Ecology Matsinos 49

Conversion to agriculture causes loss of half of soil carbon within a few decades 12/2/2022 Landscape Ecology Matsinos 50

Extensification • 1. Land-use conversion • 2. Land-use modification – (most widespread human impact) – Grazing and burning of grasslands – Expansion of marine fisheries 12/2/2022 Landscape Ecology Matsinos 51

Intensification • Agriculture – Addition of fertilizers and pesticides – Runoff to aquatic ecosystems • Aquaculture – Fish farming – Shrimp farming 12/2/2022 Landscape Ecology Matsinos 52

Spatial and temporal scaling are essential to understand the global consequences of changes in ecosystems • Study plots are a miniscule proportion of globe • Want to project results back and forward in time 12/2/2022 Landscape Ecology Matsinos 53

Dominant controls over ecosystem processes depend on temporal scale 12/2/2022 Landscape Ecology Matsinos 54

The dominant controls over ecosystem processes change with temporal and spatial scale 1. Rapid, small-scale processes provide mechanism of larger-scale processes 2. Slow, large-scale processes are “constants” that provide context for faster, smaller-scale processes 12/2/2022 Landscape Ecology Matsinos 55

Approaches to spatial scaling • 1. Assume homogeneity 12/2/2022 Landscape Ecology Matsinos 56

Assuming Homogenous Space Global NEP simulated by the Terrestrial Ecosystem Model (TEM) assumes homogeneity within biomes to predict broad-scale patterns. 12/2/2022 Landscape Ecology Matsinos Eddy flux towers physically average measurements over area ~1 km 2. 57

Approaches to spatial scaling • 1. Assume homogeneity • 2. Paint by numbers – Multiply observed pool/flux by aerial extent of ecosystem – Provides rough approximation – Success depends on: • • Representativeness of measured values Accurate aerial extent of ecosystem types Inclusion of hot spots Homogeneity of process within an ecosystem type 12/2/2022 – (or valid regression Landscaperelationship Ecology Matsinos with indicator variable) 58

Mosaics • Paint-by-numbers–no interaction among sites, but not trivial! – Complex with multiple drivers or change through time – Need spatial distributions of each driver to predict process – Need the known relationships to predict for each site (cell) – Regression useful 12/2/2022 Multiple regression used to “paint by numbers” Landscape Ecology Matsinos 59

Mosaics • Advanced paint-by-numbers–no actual transfers among sites needed, but the context surrounding a site must be considered • Predictive model now based on the site plus surrounding neighborhood. • Composition and/or configuration within some distance needed to predict rate • Regression used here • Spatial statistics also useful 12/2/2022 Landscape Ecology Matsinos 60

Approaches to spatial scaling • 1. Assume homogeneity • 2. Paint by numbers • 3. Regression relationships – Scaling rules: e. g. , NPP-NDVI relationship – Generalizations that relate NPP, decomp, ET, etc. , to resource availability • 4. Process-based models – Must understand temporal and spatial scales of important controls Ecology processes Matsinos – 12/2/2022 Must understand. Landscape important 61

Ecosystem models differ in processes and controls Represented Optimal model structure depends on modeling goals 12/2/2022 Landscape Ecology Matsinos 62

Approaches to spatial scaling • • • 1. Assume homogeneity 2. Paint by numbers 3. Regression relationships 4. Process-based models 5. Large-scale measurements – Eddy covariance to measure carbon exchange • Averages across hot and cold spots – Inverse modeling based on atmospheric concentrations 12/2/2022 Landscape Ecology Matsinos 63