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Climate change & future in gardens and preserves sierra club 2017


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Talk to Sierra Club chapter on effects of climate change on local gardens and nature preserves

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Climate change & future in gardens and preserves sierra club 2017

  1. 1. © Project SOUND Climate Change & the Future of Local Parks, Preserves and Gardens Constance M. Vadheim - CSUDH (emeritus) Palos Verdes-South Bay Group/Los Angeles Chapter of the Sierra Club - 2017 April 26, 2017
  2. 2. 15 of the past 16 years have been the warmest on record – that’s a trend we can’t deny! © Project SOUND slowdown-in-global-warming-in-recent-years.html
  3. 3. But, why worry about slightly warmer temperatures (in Los Angeles County)? © Project SOUND
  4. 4. © Project SOUND What, specifically, does climate change mean for the South Bay & for S. California?
  5. 5. Predicting future climate: always difficult  Problems of scale:  Dealing with large scale/global causes & effects  Small scale – what individuals/ states, etc. are interested in  Many factors (and their interactions) are important  Some factors are unpredictable (volcanic eruptions)  No long-term data on many of these factors  We’ve never experienced changes anything like this © Project SOUND
  6. 6. Atmosphere/ocean/sea-ice general circulation models (AOGCMs)  Three-dimensional models of the global atmosphere used in climate modeling  Couple atmospheric GCMs (AGCMs), oceanic GCMs (OGCMs) and increasingly additional data.  Based on laws of physics  Complex – require big computers & lots of time to run the simulations  Results are ‘checked/verified’ by comparing to past/present  Used to predict the effects of climate change © Project SOUND Global atmospheric modeling began in the mid-1950’s
  7. 7. Factors that go into currant AOGCM models  The hydrosphere: the oceans and other bodies of water  The cryosphere: including sea ice, glaciers and ice sheets  The atmosphere: composition and behavior  The biosphere: the amounts and types of animals and plants  The geosphere: tectonic variations such as volcanic eruptions and moving continents © Project SOUND tough-gig/
  8. 8. Hadley Model - average maximum temps © Project SOUND
  9. 9. Predicting future climate on a smaller, local scale is much more difficult © Project SOUND
  10. 10. Most planners currently use data from several models (and several scenarios) to predict  When models concur, the result is more likely to be correct  Can compare models and try to understand the reason for the differences – increases our understanding of the processes  Allows to ‘bracket’ what the likely effects will be © Project SOUND
  11. 11. Cal-Adapt: California’s climate change data/ mapping source  Developed by UC Berkeley's Geospatial Innovation Facility  Data have been gathered from California’s scientific community, and represent the most current data available wherever possible.  Provides data and maps to planners, researchers and the public – Climate Tools are easy to use. © Project SOUND http://cal- climate-models/
  12. 12. The Climate Change in the Los Angeles Region Project  Series of studies by atmospheric scientists at UCLA (and others)  Employ innovative techniques, applying multiple global climate models to the Los Angeles region  Goal: to provide detailed projections of climate change (through 2100)  Why important? Direct planning at all levels (National/state government to your own backyard) © Project SOUND Read about it yourself: • • •
  13. 13. First Report (2012):"Mid-Century Warming in the Los Angeles Region."  By mid-century, Los Angeles will experience temperatures similar to what we experience today about 75- 80% of the time (274-292 days a year)  If we don't reduce global greenhouse gas emissions, Los Angeles will continue to get warmer. By the end of the century, temperatures will be like they are today only 50- 65% of the time (1 83- 243 days a year) © Project SOUND • hotter than normal temperatures will likely be experienced primarily in late summer and early fall (our typical hot, dry period). • December to January and July to August are projected to change the most (relative to today).
  14. 14. What difference can a few degrees change have on our local plants and animals? © Project SOUND
  15. 15. Thankfully, plants are pretty adaptable (they have to be to survive)  Plants usually have several back-up systems for dealing with specific environmental stresses.  Local species tend to be adaptable – we live in a fickle Mediterranean climate  Many local plant species tolerate a range of:  Light conditions  Yearly precipitation  Soil nutrients & pH  Temperatures  Each plant species is unique – some are more adaptable than others. © Project SOUND
  16. 16. In local Parks & Preserves, the direct effects of more high temperature days (taken alone) will probably be small  We will only have 5-20 days > 95°/year  Many native plants have adaptations that allow them to withstand some ‘high heat’  Local native plants programmed to ‘expect’ high temperatures in late summer/fall  But remember:  These are averages – some years will have many more hot days & some will be in winter  Increasing temperatures lead to other climate changes  Each plant is different – some are more heat-tolerant than others © Project SOUND World-wide, plant species tend to be affected (stressed) by temperatures > 85° F.
  17. 17. Local Preserves are affected by urban heat island effects  Some microclimates are hotter than the average (due location)  Suburban areas retain more heat – and are noticeably hotter – than surrounding rural areas © Project SOUND
  18. 18. © Project SOUND We will likely see some direct effects of heat on plants in local urban/suburban parks, preserves and gardens
  19. 19. But temperature has important indirect effects on plants as well…and some of these are critical  All plants have optimal temperature ranges – in general, plants from hotter places have higher ranges  Temperatures higher and lower than the optima affect literally everything a plant does:  Taking up water  Growing new leaves, branches  Producing flowers, fruits & seeds  Warding off pests & diseases  Timing of life & seasonal changes  Just plain staying alive! © Project SOUND applications-in-agriculture/extreme-temperature-responses-oxidative- stress-and-antioxidant-defense-in-plants temperatures just beyond the optimal range can greatly affect both survival and reproduction
  20. 20. Some local plants have lower optimal temperatures  Lower optima: [California encelia]  Often perennial plants that grow rapidly in winter or early spring  Often flower in spring – but may in cooler fall period  May be completely/mostly dormant in summer/fall (but not always) – avoid heat and drought  Includes a number of local shrubs, perennials, grasses, bulbs  Give gardens/Preserves spring color  Higher optima: [Coast quailbush]  Grow and flower in warm weather of later spring, summer  May be evergreen; shrubs w/ deep roots  Includes some local plants, warm season grasses, some desert plants © Project SOUND Calif. encelia Coast quailbush
  21. 21. Studies on food plants document the effects of high temperatures on food plants grown in local gardens Food Plant High Temperature Effects (shown by research) Tomato Reduced fruit number (with only slight ↑ temp) Lettuce  Shortened growing season  Increased incidence of tip burn  Early bolting (flowering onset) Stone fruits Decreased fruit size and quality (effects of both higher temps & decreased chill hours) Citrus Reduced frost losses and increased yields in N. CA; possible decreases in S. CA Grapes  Premature ripening and possible quality reduction  Increased yield variability © Project SOUND
  22. 22. © Project SOUND Anything that affects plants will also affect the animals that depend on them Climate change will affect plants in local Preserves and gardens (sometimes indirectly)
  23. 23. Heat is not just annoying – it stresses most living things (including humans)  Greater risk of death from dehydration, heat stroke/ exhaustion, heart attack, stroke, and respiratory distress  By mid-century, extreme heat events in urban centers such as Los Angeles are projected to cause two to three times as many heat- related deaths as there are today.  High temperatures stress living creatures - from bacteria to mammals. © Project SOUND thermometer-or-thermostat-leader/
  24. 24. Garden strategies to combat heat: create shade with trees, large shrubs & vines  Look closely at your existing trees  Are they healthy? Young enough to survive your lifetime? In the right places to provide needed shade?  Plant trees to S & W of buildings NOW  Choose trees/large shrubs that provide ‘value added’; fruits; habitat value; etc.  Choose water-wise native species if possible © Project SOUND Use vines and trellises creatively; native vines have many good attributes in addition to their shade
  25. 25. December to January and July to August are projected to change the most (relative to today) © Project SOUND  What can we expect (S. Bay)?  Warmer nights (on average) in summer  Warmer days in winter (on average)  Warmer nights in winter; fewer nights below 45° F. The more heat-absorbing surfaces that surround us, the warmer the nights (whenever we have sunny days)
  26. 26. Decreasing hours of chill: bad for W. Coast agriculture  ‘Chill factor’ – the number of hours below a certain temperature required to trigger some plant behavior (often flowering)  Most important for fruiting trees/shrubs, ‘winter annuals’ and biennials  Fruit and nut production in California will likely be seriously affected  May also affect those of us that grow ‘low chill’ fruits in home gardens [Anna apple; Fuji apple; Black Mission fig; Santa Rosa plum] © Project SOUND DECREASING CHILL HOURS, 2070-2099
  27. 27. How will decreased hours of chill affect local native plants (in gardens & Preserves)?  Some native shrubs from slightly higher elevations, more northern latitudes and the high desert (which experience more chill) will likely not produce as well/reliably:  Manzanita?  Native cherries & other Prunus  ? Coffeeberry & other Rhamnus species  ??? Hard to predict  Research is desperately needed on native species that provide food for birds & other creatures. © Project SOUND Lots of research on effects of heat on crop species – very little on native plant species
  28. 28. Subtle changes in temperature can effect sensitive systems – in plants and in the climate/environment  Global/local temperatures (including ocean temperatures) affect:  Precipitation: amount, timing and type  Winds: patterns, timing, velocity  Humidity: degree, timing  Soil conditions: moisture, organisms Everything is interconnected
  29. 29. In fact, the last 5 years have been a pretty good lesson in stress & ecosystems © Project SOUND
  30. 30. © Project SOUND heat smog drought Santa Ana winds unusual rain patterns Yep, it’s all interconnected – small changes in temperature can have big effects
  31. 31. Precipitation changes in U.S. : 1901-2015 © Project SOUND precipitation  Most of the U.S. saw increased precipitation  The Southwest (including S. CA) saw significant decreases
  32. 32. The past 5 years have taught us about drought  All of California in some level of drought 2013-2016  Estimated Population in Drought Areas: 36,660,308 © Project SOUND
  33. 33. Yearly precipitation : hard to predict © Project SOUND  The period October through March tends to be wetter than usual in a swath extending from southern California eastward across Arizona, southern Nevada and Utah, New Mexico, and into Texas.  In rainy years, there are more rainy days, and there is more rain per rainy day. El Nino winters can be two to three times wetter than La Nina winters in this region.
  34. 34. Predicting S. California’s future precipitation is challenging © Project SOUND  Role of El Nino events is not well understood – and they have a role in our precipitation  We have complex topography  Our area lies right between two areas on which most models agree:  An area of more precipitation to the north  An area of significantly less precipitation to the south
  35. 35. “21st Century Precipitation Changes over the Los Angeles Region” - 2014  Major findings:  Probably about the same amount of precipitation overall (some models suggest slightly higher – some slightly lower)  Continued high year-to-year variability  Less precipitation falling as snow (40% decrease in snowfall) due to increasing temperatures  Higher wintertime stream/runoff flows  Need to capture/infiltrate to conserve as much water as possible  For more see: _V2.pdf © Project SOUND
  36. 36. Slight decrease or slight increase?  Probably wisest to assume somewhat drier conditions – and less water available for home gardens  Year-to-year variability will likely increase  Plan for drought years  Plan enough flexibility to deal with wet years:  Plant choices  Water infiltration/ conservation © Project SOUND PV peninsula Much of South Bay Los Angeles average since 1877 thru 2012 (135 years): 14.98 inches
  37. 37. Local precipitation is influenced by many factors  Large scale  Overall global temperatures & temperature gradients  Ocean temperatures and temperature gradients  Location of the Polar and Subtropical Jet Streams  Many other factors, including some we know little about  Local  Proximity to the ocean  Local temperature gradients (specifically, desert vs. coast)  Elevation  Location in relationship to mountain ranges © Project SOUND
  38. 38. 2016: Where’s our El Niño?  Many areas are getting above normal precipitation. Why aren’t we?  Blame it on a strong mass of high pressure  Heats our atmosphere  Causes the wet, subtropical Jet Stream to move North or South (keeps it out)  Brings us (you guessed it) Santa Ana Winds © Project SOUND Los Angeles Times – January 22, 2016
  39. 39. We can’t really explain why the masses of high pressure have been so strong/constant recently  We do know they’ve influenced our weather – significantly - for at least the past 4 years  That’s reason for concern – is this our new normal?  Are the past 5 years a taste of things to come? Many implications for Western L.A. County. © Project SOUND
  40. 40. © Project SOUND
  41. 41. Local Preserves & gardens are now vulnerable to heat waves throughout the year  High temperatures are often accompanied by dry conditions.  Santa Ana conditions constitute a ‘double (maybe triple) whammy’. © Project SOUND
  42. 42. © Project SOUND California wildlands dramatically illustrate the combined effects of heat, drought & wind
  43. 43. We needn’t discuss the direct effects of drought on local gardens © Project SOUND  Longer ‘fall warm period’ – lasting well into December or later in some years  ? More variable/earlier onset of spring warm season  ? Shorter rainy season  Drying winds
  44. 44. Plants are particularly sensitive to the effects of temperature & moisture at certain stages of development  Seed germination  Development of the flower (particularly the pollen-producing organs)  Pollen production & viability  Pollen transfer (‘pollination’)  Actual fertilization process (several steps)  Seed/propagule development © Project SOUND Note that all of these impact the reproductive success of a plant – and ultimately of a species
  45. 45. Stages of the reproductive cycle have to happen at the right time – timing is everything  Temperature  Soil moisture  Humidity  Light  Pollinator availability  Seed distribution system availability © Project SOUND So, over time, plants have modified their reproductive cycles to synchronize with their local climate reproduction
  46. 46. Plants regulate their daily and yearly behaviors based on cues from the environment  Intensity and color of light  Periods of light and dark  Temperature  Soil moisture (precipitation)  Physical factors  Wind  Other, including chemicals in the air, water & soil  Animals  Other plants © Project SOUND
  47. 47. The ‘constant cues’ are necessary for things to happen at the ‘right time’ © Project SOUND
  48. 48. Many types of plant behaviors are temperature regulated (in at least some plants)  All or none effects  Flowering  Fruiting  Seed germination  Timing (earlier/later) effects  Timing of bud-set; leaf-loss  Timing of bud-break (leafing out)  Timing of seed germination  Timing of flowering & fruiting © Project SOUND
  49. 49. What types of temperature cues do plants use to regulate behaviors?  Number of hours below a certain temperature in a year (chill factor)  Number of days above a certain temperature  Number of consecutive days below a certain temperature  The difference between high and low temperatures in a 24 hour period © Project SOUND Plants use the most reliable cues (in their particular climate) to ensure that key behaviors (like pollen production) don’t happen too soon behaviorurldefaultvmlo.html
  50. 50. What happens when ‘constant’ environmental cues change too quickly? These are the questions that keep biologists and Preserve Managers awake at night! © Project SOUND
  51. 51. The ‘Perils of Pollen’: is pollen the weak link in our hotter, drier, more variable world?  Direct effects:  Production of viable pollen  Pollination/fertilization (pollen germination, pollen tube growth, and fertilization)  Indirect effects:  Timing/development of female flowers or floral parts  Pollinator availability (biologic & abiotic)  Pollination/fertilization (pollen-stigma interaction, fertilization) © Project SOUND The consequences of incorrect timing can be catastrophic
  52. 52. So what – I’ll just go and buy some more seed © Project SOUND
  53. 53. If a plant species can’t reproduce, ultimately it will die out, at least in that area © Project SOUND Native grasses failed to reproduce Any plant species loss has the potential to affect all the animal species which depend on it
  54. 54. The timing of a plant’s life cycle is not just important for the plant © Project SOUND
  55. 55. Plants, animals and seasons: disturbing new trends world-wide  Many plant species are responding to climate change by advancing the onset of events in the yearly cycle.  The earlier onset of bud burst, flowering, and fruiting could have major impacts on timing-sensitive relationships with pollinators, seed dispersers, and herbivores.  Events that have long occurred in synchrony may become decoupled, which could especially impact plant species with specialized pollinators and seed dispersers. © Project SOUND
  56. 56. We need also consider the direct effects of climate change on pollinators, other insects and reptiles/amphibians  Some species – and types of animals – are more vulnerable  Animal reproduction and survival are directly influenced by:  Temperature  Water  Soil moisture  Wind  Air pollutants  Both plants and animals are facing new biotic challenges – pests and pathogens © Project SOUND
  57. 57. Air pollution: what can we expect in the future?  ↑ emissions due increased population?  Smoke from wild fires  ? More stagnant air  ? More particulates (due to decreased precipitation)  Because warm, stagnant air tends to increase the formation of ozone, climate change is likely to increase levels of ground-level ozone in already-polluted areas and increase the number of days with poor air quality © Project SOUND
  58. 58. Santa Ana winds & air pollution in western L.A. county  Santa Anas (off-shore flow) mean more air pollution in our area – you may have noticed this recently  ? Longer season for Santa Anas  Maybe 20% fewer Santa Ana events as winter temps in desert increase  But even past records suggest more extremes © Project SOUND ana-wind-conditions.html wind-season-may-be-stretched-by-climate-change/
  59. 59. Heat, drought and air pollution can increase plant susceptibility to pests & pathogens © Project SOUND Polyphagous shot hole borer
  60. 60. Plant diseases are changing  In both animals and plants, an unprecedented number of fungal and fungal- like diseases have recently caused some of the most severe die-offs and extinctions ever witnessed in wild species, and are jeopardizing food security.  Consequences for local Preserves and gardens:  More severe effects of old pests (plants are less able to cope)  New pests adapted to the changing climate: temperature & precipitation The past two decades have seen an increasing number of virulent infectious diseases in natural populations and managed landscapes.
  61. 61. Temperature & precipitation: the most important influences on plant distribution
  62. 62. What will a future California look like?
  63. 63. The grim realities: plant communities in a time of significant climate change  Climate change is already impacting plants and altering the structure of plant communities.  Species that are particularly vulnerable to climate change include:  Those with limited ranges and dispersal abilities (long lifespan and/or limited seed dispersal.  Some isolated or disjunct species (including those isolated by human incursion)  Plant genetic composition may change in response to the selection pressure of climate change. © Project SOUND
  64. 64. The grim realities: plant communities in a time of significant climate change  Evidence from historical plant migrations (e.g. those that occurred at the end of previous ice ages) suggests that while some species will migrate to areas with appropriate climates, many plant species will not be able to migrate fast enough to keep pace with current rates of warming.  Some plant communities or species associations may be lost as species move and adapt at different rates. © Project SOUND
  65. 65. The grim realities: plant communities in a time of significant climate change  Increased invasions by alien species may occur, as conditions become more suitable for exotic species whilst native species become less well suited to their environment. © Project SOUND
  66. 66. Some winners and losers based on our five-year drought: local results  Winners  Large coastal sage scrub, chaparral & oak woodland evergreen shrubs & trees  Local native sub-shrubs that are dry- season dormant  Desert wash/seasonal riparian species  Native/non-native plants that got a little supplemental water  Invasives: grasses, herbaceous weeds  Losers  Smaller local species: grasses, herbaceous perennials; ?? some annuals  Riparian species  Natives from N. CA (in our area) © Project SOUND
  67. 67. What will our climate be like in the S. Bay? 1. Slight overall incr. in average temperatures, # high heat days 2. Significant changes in the temperature patterns:  Hotter July & August  Warmer winter/early spring  Warmer night temperatures – and less winter chill  More year-to-year temperature extremes © Project SOUND
  68. 68. What will our climate be like in the S. Bay? 3. Significant changes in the timing of seasons:  Longer fall dry season (into December or even longer)  Earlier spring (at least in some years)  Shorter winters 4. About the same amount of precipitation 5. More precipitation extremes: droughts and floods 6. Timing of onset of rains more variable © Project SOUND
  69. 69. What will our climate be like in the S. Bay? 7. More rain/less snow as temperatures rise. ? less irrigation 8. ? More (or less) frequent Santa Ana winds (all year-round - not just in fall/winter) 9. ? More smog © Project SOUND
  70. 70. What will be the likely consequences for plants and animals? 1. Some plants will be killed outright by temperature & precipitation extremes (including some that are not really so extreme) 2. Some plants will have a tough time reproducing, due to either direct or indirect consequences of temperature/precipitation 3. Changing seasonality may disrupt long-standing synchronicities:  Plants & weather  Plants and pollinators  Plants and other beneficial creatures © Project SOUND
  71. 71. What will be the likely consequences for plants and animals? 4. Some native plant species may not survive 5. The biodiversity in local native plant communities will change 6. Non-native invasive species – especially those better suited to the changing climate – will become more of a problem 7. New diseases & pests (of both plants and animals) will also affect biodiversity in Preserves and gardens © Project SOUND
  72. 72. What will be the likely consequences for plants and animals? 8. Temperature/precipitation & pollution extremes will render some plants more vulnerable to pests, pathogens, etc. 9. Animals of all sorts and sizes will likely be more vulnerable to starvation; creatures having more specialized relationships with plants will be most vulnerable © Project SOUND
  73. 73. What will be the likely consequences for plants and animals? 10. The biodiversity of creatures inhabiting our Preserves and gardens will likely change:  Due to direct effects of temperature, precipitation, etc.  Due to indirect effects:  Changing plant community  Changing predator/pathogen community  Dis-synchronicities that affect breeding and food sources © Project SOUND
  74. 74. Steps we can take, right now, in our gardens (home, school, parks, other)  Plant a water-wise tree for shade  Choose water-wise natives over non- natives  Better suited for our climate, soils  Provide better habitat  Re-think how we choose plants (gardens are more ‘insulated’ from drought)  Choose native plants that are rare/ endangered  Choose plants that provide habitat (may be critical in some years)  Choose hardy, drought-tolerant species (may be less susceptible to pests/disease/ etc. © Project SOUND
  75. 75. More steps to take  Let garden plants provide food: seeds, fruits, vegetation  Plant with the seasons – it stresses plants less  Change your watering strategy: good deep watering in winter/spring [we’ll have to educate our water companies]  Be sure that every drop of rain that falls on your garden stays in your garden  Be vigilant about invasive weeds and pests – certainly don’t plant any! © Project SOUND
  76. 76. Difficult choices to think about for our local Preserves  Should we water? When?  To supplement winter drought?  To allow us to do restoration in dry years?  To keep key species alive  Some plant species will not be able to reproduce in the wild. Should we artificially plant seedlings? Take other steps?  How do we prioritize species when supplying rare resources (like water) © Project SOUND
  77. 77. More difficult topics for consideration  How do we define ‘local plant community’ – static or changing?  How can we increase genetic diversity in small, local Preserves in times of climate change?  How best to maintain surveillance for invasive species, pests, pathogens? How best to combat these invaders (in a way that causes least impact on the ecosystem)? © Project SOUND
  78. 78. © Project SOUND The past few years have been stressful heat drought unusual rain patterns Santa Ana winds smog
  79. 79. But they have also taught us important lessons (if we’re willing to listen) © Project SOUND
  80. 80. …lessons that point towards the future © Project SOUND
  81. 81. © Project SOUND … and steps we can take (right now) to make that future more pleasant & sustainable