Climate Change across the Playa Lakes Region Understanding, Managing, Responding John H. Matthews, PhD Climate Adaptation Specialist, Freshwater 18 January 2008

Climate Trends Across the Playa Region With little geographic relief, the region has relatively minor microclimatic variation Two major climate gradients exist: temperature (north & south) and precipitation (east & west) Regional climate has varied widely over the past 20k yrs; otters used to live in the Texas Panhandle With little geographic relief, the region has relatively minor microclimatic variation Two major climate gradients exist: temperature (north & south) and precipitation (east & west) Regional climate has varied widely over the past 20k yrs; otters used to live in the Texas Panhandle precipitation temperature more-permanent surface water less-permanent surface water

This Period of Climate Change is Different There is not a single new climate we are moving toward; we are entering a series of new climates over the next few centuries During past climate shifts, the ranges of species moved around, but we because we have altered the natural landscape so much range shifts are far more difficult now Many species face serious non-climate threats; climate change is another log on the fire There is not a single new climate we are moving toward; we are entering a series of new climates over the next few centuries During past climate shifts, the ranges of species moved around, but we because we have altered the natural landscape so much range shifts are far more difficult now Many species face serious non-climate threats; climate change is another log on the fire Why Be Concerned Now? The climate is changing quickly; the pace of change is increasing All aspects of climate are changing, not just air temperature It hasn’t been this warm for 650k years and probably >1.5 million The climate is changing quickly; the pace of change is increasing All aspects of climate are changing, not just air temperature It hasn’t been this warm for 650k years and probably >1.5 million

Large-scale Trends: 1975–2015 wetter drier Annual precipitation is increasing over most of North America except for the southwestern USA More extreme droughts and flooding are occurring Spring precip is increasing (2 to 12%) and summer precip is declining (-15% to +4%) Winter temps are increasing more than summer temps Less snow and more rain in winter, earlier springs, longer summer & fall Annual precipitation is increasing over most of North America except for the southwestern USA More extreme droughts and flooding are occurring Spring precip is increasing (2 to 12%) and summer precip is declining (-15% to +4%) Winter temps are increasing more than summer temps Less snow and more rain in winter, earlier springs, longer summer & fall changes relative to 1990

Agricultural Impacts 100° longitude rain-fedagriculture irrigatedagriculture,ranching The 100th meridian is the traditional division between irrigated and reliably rain-fed agriculture Widespread groundwater pumping extended this boundary west, but it is moving east again Severe droughts like those of the 1930s and 1950s will become more common Higher evapotranspiration rates may counteract increased spring precipitation trends Aquifer use is likely to increase; Ag markets may need to move to “less-thirty” crops Evapotranspiration rates are increasing in several regions already Many crops maturing ~1–3 days per decade earlier over the past 50 years The 100th meridian is the traditional division between irrigated and reliably rain-fed agriculture Widespread groundwater pumping extended this boundary west, but it is moving east again Severe droughts like those of the 1930s and 1950s will become more common Higher evapotranspiration rates may counteract increased spring precipitation trends Aquifer use is likely to increase; Ag markets may need to move to “less-thirty” crops Evapotranspiration rates are increasing in several regions already Many crops maturing ~1–3 days per decade earlier over the past 50 years

Forest & Woodland Impacts Fire is likely to return as a major form of disturbance Junipers & cedars are sensitive to fires and are declining in some areas of the US & Canada Invasive insect herbivores are moving north as a result of warmer winters Increased drought stress reduces fertility Fire is likely to return as a major form of disturbance Junipers & cedars are sensitive to fires and are declining in some areas of the US & Canada Invasive insect herbivores are moving north as a result of warmer winters Increased drought stress reduces fertility

Grassland & Shrubland Impacts Native grasses are resistant to “normal” droughts Soil dynamics are changing from climate change in the prairies Severe droughts & altered soil nutrient availability spread invasive grasses and shrubs Invasive insect herbivores are also moving north Native grasses are resistant to “normal” droughts Soil dynamics are changing from climate change in the prairies Severe droughts & altered soil nutrient availability spread invasive grasses and shrubs Invasive insect herbivores are also moving north

Freshwater Habitat Impacts Unpredictable precip & temps reduces number of wetlands and size of lakes, rivers Most stable: large, permanent, deep catchments Most threatened: short-hydroperiod, small, shallow, playas in the SW Special concern: shallow warm water sloughs, dry playas, wet meadows, temporary streams, sandhills Invasive aquatic and emergent vegetation expanding with drought Land-use has a major impact on hydroperiod Unpredictable precip & temps reduces number of wetlands and size of lakes, rivers Most stable: large, permanent, deep catchments Most threatened: short-hydroperiod, small, shallow, playas in the SW Special concern: shallow warm water sloughs, dry playas, wet meadows, temporary streams, sandhills Invasive aquatic and emergent vegetation expanding with drought Land-use has a major impact on hydroperiod

Impacts: 2015–2050 Severe shortening of southern & southwestern playa hydroperiods Number of wet playas in summer/fall will decline due to higher evaporation & lower precipitation rates Migratory corridors will shift toward reliable water sources: rivers, large lakes/reservoirs. Many species will probably shift east of current routes, especially in fall Overwintering waterfowl & waterbird species will be more concentrated, located around fewer & smaller water bodies Avian disease tranmission frequency will increase as a result Changes in soil moisture, nutrient availability will favor invasive grasses & insect herbivores Fire frequency will increase, reducing deciduous forest cover and mature prairie, juniper, and cedar stands Severe shortening of southern & southwestern playa hydroperiods Number of wet playas in summer/fall will decline due to higher evaporation & lower precipitation rates Migratory corridors will shift toward reliable water sources: rivers, large lakes/reservoirs. Many species will probably shift east of current routes, especially in fall Overwintering waterfowl & waterbird species will be more concentrated, located around fewer & smaller water bodies Avian disease tranmission frequency will increase as a result Changes in soil moisture, nutrient availability will favor invasive grasses & insect herbivores Fire frequency will increase, reducing deciduous forest cover and mature prairie, juniper, and cedar stands

Winners Bird species that breed in the playa region in spring may do well with more precip, milder winter Species with ranges now to the south and SW of the playa region will be moving north as “native exotics” Species that are habitat generalists and found in other regions of the continent may prove more flexible Species that consume primarily insects & plants rather than amphibians/reptiles Species that are not threatened elsewhere in their range Bird species that breed in the playa region in spring may do well with more precip, milder winter Species with ranges now to the south and SW of the playa region will be moving north as “native exotics” Species that are habitat generalists and found in other regions of the continent may prove more flexible Species that consume primarily insects & plants rather than amphibians/reptiles Species that are not threatened elsewhere in their range

Habitat specialists, as a group Species that consume amphibians Species that breed in summer or show drought mortality Species that forage or breed in fire-sensitive habitats Species that migrate south in late summer/early fall Species already facing population declines Species that prefer deeper playas & wetlands Habitat specialists, as a group Species that consume amphibians Species that breed in summer or show drought mortality Species that forage or breed in fire-sensitive habitats Species that migrate south in late summer/early fall Species already facing population declines Species that prefer deeper playas & wetlands Losers

New Planning Tools? PLJV could model precipitation, hydroperiod, land use, and evapotranspiration interactions under different climate scenarios 2007 Wetlands paper from Smith lab (Tsai et al. [27(3)] is an excellent start, but data from other regions is needed; must link weather with climate How much regional variation will exist? Will precipitation increases outweigh ET increases in the sandhill wetlands? Should the PLJV form a climate monitoring/analysis/study network or partnership? PLJV could model precipitation, hydroperiod, land use, and evapotranspiration interactions under different climate scenarios 2007 Wetlands paper from Smith lab (Tsai et al. [27(3)] is an excellent start, but data from other regions is needed; must link weather with climate How much regional variation will exist? Will precipitation increases outweigh ET increases in the sandhill wetlands? Should the PLJV form a climate monitoring/analysis/study network or partnership?

Issues to Consider The Conservation Reserve Program protects many playas; how can this program be improved/extended? Will shifts in crops and ranching alter availability of surface water? How to address increasing late-summer and early-fall impacts: fewer & smaller water bodies, containing less water with lower water quality? How can farmers and ranchers actively help in improving grassland and playa quality & quantity in a changing climate? The Conservation Reserve Program protects many playas; how can this program be improved/extended? Will shifts in crops and ranching alter availability of surface water? How to address increasing late-summer and early-fall impacts: fewer & smaller water bodies, containing less water with lower water quality? How can farmers and ranchers actively help in improving grassland and playa quality & quantity in a changing climate?

Conclusions The climate is already changing Spring precipitation is increasing but will likely decline in other seasons, resulting in a regional net drying The number of wet playas in summer/fall will likely decrease Climate analyses should be incorporated into planning in the same way as GIS analyses The ultimate impact may also depend on how farmers and ranchers respond to economic challenges of climate change The climate is already changing Spring precipitation is increasing but will likely decline in other seasons, resulting in a regional net drying The number of wet playas in summer/fall will likely decrease Climate analyses should be incorporated into planning in the same way as GIS analyses The ultimate impact may also depend on how farmers and ranchers respond to economic challenges of climate change

Author contact information: John H Matthews, PhD Climate Adaptation Specialist, Freshwater World Wildlife Fund Author contact information: John H Matthews, PhD Climate Adaptation Specialist, Freshwater World Wildlife Fund