C. DAVID BERTELSEN Adjunct Associate Research Scientist, UA SNRE Associated Researcher, UA Herbarium PRESENTED AT THE R.I.S.E. SYMPOSIUM OCTOBER 26, 2019 5 ≈1100 ac (0.6% of the entire range) I’ve explored only ≈ 80 ac on foot, Mt. Kimball Trail (white line) including the trail, 3.5 miles of the 4158 ft elevation gain canyon bottom, and several side drainages. 4 First hiked to Mt. Kimball in 1981 Data collection began in 1984 along five 1-mile long transects 3 SANTA 2 CATALINA MOUNTAINS 1 RINCON MOUNTAINS X CHECKLIST FOR DATA COLLECTION 1711 hikes to the peak (over 17,350 miles including X shorter hikes) 181,056 flowering records 82,573 vertebrate records 263,629 total records Cool Season (November-March) Tradescantia occidentalis SW CLIMATE: VARIABILITY AND DROUGHT Cool Season (November-March) The current drought is now the 4th worst megadroughtWarm Season (May in 1200-October) years SOURCE: Woodhouse et al. (2010) A 1,200-year perspective of 21st century drought in southwestern North American. PNAS 107:21283-21288. More frequent and prolonged drought is symptomatic of climate change Tradescantia occidentalis -10 -3 -2 -1 10 15 0 1 2 3 4 5 -5 0 5 Climate data source: www.prism.oregonstate.edu source: data Climate 1984 1984 89 the beenabove have area the study in temperatures annual average Since 1994, 1985 1985 PRECIPITATION ANOMALIES, 1984 ANOMALIES, PRECIPITATION 1986 1986 1984 ANOMALIES, TEMPERATURE 1987 1987 1988 1988 1989 1989 1990 1990 1991 1991 1992 1992 1993 1993 1994 1994 1995 89 the above been has precipitation annual years, 25 last the In 1995 1996 - 1996 1998 in except average year 1997 1997 1998 1998 1999 1999 2000 2000 - 2001 2001 - 2018 (0 = 1930 2018 (0 = 1930 2002 2002 2003 2003 2004 - 2004 year average in only 7 years 7 only in average year 2005 2005 2006 2006 2007 2007 - 2008 2008 - 2018 AVERAGE) 2018 AVERAGE) 2009 2009 2010 2010 2011 2011 2012 2012 2013 2013 2014 2014 2015 2015 2016 2016 2017 2017 2018 2018 -10 10 15 -5 0 5 83-84 84-85 85-86 86-87 87-88 88-89 89-90 90-91 91-92 92-93 93-94 warm seasons. warm 89 the above significantly been has 1994 precipitation October Since 94-95 95-96 96-97 97-98 98-99 99-00 - year averages in only 6 cool seasons and 6 and seasons 6 cool onlyin averages year 00-01 01-02 02-03 03-04 04-05 05-06 06-07 07-08 08-09 09-10 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 18-19 Funastrum heterophyllum Responses at the species level, not at the community level Phenology changes (i.e., earlier or later onset of flowering, changes in length of growing seasons); Changes in abundance (i.e., increases, decreases, and disappearances); Changes in composition (i.e., in growth forms and non-native species); and Shifts, extensions, and contractions of species ranges to higher elevations/latitudes. Funastrum heterophyllum Carnegiea gigantea Carnegiea gigantea Castilleja tenuiflora “Although species extinctions are of great evolutionary importance, and will generally cause greater impacts on ecosystem function.” Dirzo, R.D., H.S. Young, M. Galetti, G. Caballos, N.J.B. Isaac, and B. Collen (2018) Defaunation in the Anthropocene. Science 345: 401-406 “We conclude that any mechanism of global change that selectively destroys small habitat patches will lead to imminent extinctions in most discrete metacommunities.” Deane, D.C. and F. He (2018) Loss of the smallest patches will reduce species diversity in most discrete habitat networks. Global Change Biology 24:5802-5814 Castilleja tenuiflora Allium macropetalum Today I will describe some of the cumulative changes—which I think are fundamental and transforming—that have occurred in less than 20 years. These changes involve both sudden and gradual change. Sudden change is hard to miss. Gradual change, however, is difficult to detect. It’s hard to see what isn’t there—even if you have baseline data. Gradual change is usually unrecognized until cumulative effects result in crossing a threshold. Allium macropetalum Arizona black rattlesnake (juvenile) Reticulate Gila Monster Arizona black rattlesnake (juvenile) Reticulate Gila Monster Lupinus sparsiflorus Abutilon parishii Hackelia ursina Stachys coccinea All of the flowers shown in this presentation are of species that have declined or disappeared since 2002. Hesperidanthus Heuchera sanguinea linearifolius Circium arizonicum Agastache rupestris During the first 11 years of my study the only significant change I was aware of was the steady increase in the number of plant taxa I was seeing— likely because the 1970s were relatively dry and the 1980s, relatively wet. 90% of the current flora Lupinus sparsiflorus hadAbutilon been parishii identifiedHackelia by ursina1994. Stachys coccinea All of the flowers shown in this presentation are of species that have declined or disappeared since 2002. Relatively little change in the flora was seen in the next 7 years. When I first saw significant changes in vegetation in 2002, I began to consciously look for change, and the more I looked, the more I saw. Having an 18-year baseline certainly facilitated recognition ofHesperidanthus the impacts of on-going drought. Heuchera sanguinea linearifolius Circium arizonicum Agastache rupestris Graptopetalum rusbyi Because annuals tend to track climate fluctuations while perennials are better adapted to long-term climate variability, perennials are probably better indicators of climate-driven impacts to ecosystems There has been little or no recruitment of perennial species in decline. Graptopetalum rusbyi DESERT SCRUB ≈ 2O.9% OF TOTAL AREA, 41% OF FLORA (251 TAXA) At all elevations, annuals are most susceptible to decreasing precipitation. But in desert scrub, annuals make up 44% of the taxa. Since 2002, native spring annuals have not rebounded in years with good winter precipitation resulting in considerably more bare ground. Has there been a reduction in the seed banks? Non-native annuals continue to quickly respond to improved conditions. Carlowrightia arizonica • 185 Saguaros have died, including 35 in 2002, 24 in 2011, and 7 so far this year. Most mortality has been on the west side of the canyon and usually occurs late May & June. • Compass Barrel Cactus, once dominant, has been nearly replaced by a faster growing hybrid barrel (Compass x California Barrel). Nearly all mortality has been of Compass Barrel. Carlowrightia arizonica Cylindropuntia versicolor • Most native grasses (e.g., Bush Muhly, Fescues, Fluff Grass, and the ternipes variety of Spidergrass) are nearly gone, but Lehmann Lovegrass, Natal Grass, Buffelgrass, Mediterranean Grass, and Soft Feather Pappusgrass (all invasive) have increased. • Parry Penstemon, once common here, is now rare. The center of the population has shifted to Oak Woodland, more than 1200 ft higher.Cylindropuntia versicolor Xeroriparian systems, characterized by intermittent streams, merit a lot more attention because of their high biodiversity and the fact that they serve as refugia in times of drought. Such systems are likely to be the future state of the lush riparian areas we love so much. Commelina erecta • Most native species typical of riparian areas such as Flatsedges, Rushes, Cupgrasses, Hummingbird Trumpet, Yellow Monkey Flower, and Hooker Evening Primrose have sharply declined or disappeared. • The number of Engelmann x Tulip Pricklypear hybrids has increased. Commelina erecta Passiflora mexicana • Most non-native annual grasses such as Wild Oats, Wild Barley, and Rabbitfoot Grass have declined, but Buffelgrass, Annual Bluegrass, Fountain Grass, and invasive Pappusgrass have increased greatly. • The highly invasive African Sumac tree began to invade the canyon bottom in 2006. It’s still being sold in nurseries and is well established along the Rillito. These canyon drainages provide a direct link between urban, suburban, and wildland areas. Passiflora mexicana SCRUB GRASSLAND ≈7.8% OF TOTAL AREA, 49.8% OF FLORA (305 TAXA) Scrub Grassland is limited here, but until recently it has been dominated by native grasses. 44 native grass taxa have been observed on this slope. This is changing, however, and this association will be likely be transformed into an “Africanized” grassland dominated by non- natives, particularly Lehmann Lovegrass and invasive Pappusgrass. Fire would likely hasten this change. Cnidoscolus angustidens • As many native grasses (e.g., Longtongue Muhly, Cotta grass, Green Spangletop, and the ternipes variety of Spidergrass) have declined, Lehmann Lovegrass, invasive Pappusgrass, and Stink Grass have increased exponentially. • In 2015-2017, meter-high invasive Pappusgrass (an annual) was so dense on one slope that it crowded out nearly all native grasses, including Bull Grass, Side-Oats Grama, Hairy Grama, Cane Beardgrass, and Arizona Cottontop (all perennials). • ` Cnidoscolus angustidens Dipterostemon capitatus subsp. pauciflorus • In the summers of 2013 and 2014, 58 Staghorn Chollas and many Engelmann Pricklypears died; but the Englemann x Tulip Pricklypear and the Barrel Cactus hybrids have increased. • Wavy Cloak Fern has replaced Scaly Cloak Fern. Dipterostemon capitatus subsp. pauciflorus OAK WOODLAND ≈32.9 % OF TOTAL AREA, 49.3 % OF FLORA (303 TAXA) If current trends continue, this will likely become Scrub Grassland as trees and large shrubs continue to die. Lehmann Lovegrass remains the dominant grass species in the area burned in 2015. In the burn area, more native species have reappeared in Oak Woodland than in Oak- pine Woodland, but native diversity has declined sharply in both areas. Fire would likely hasten the conversion. Oxalis albicans • Mohave Penstemon and Wild Cotton are the only native species that clearly benefited from the fire, at least from what I’ve seen so far. • Many herbaceous perennial, subshrub, and shrub species have declined. • All reproductive Palmer agave plants were gone by 2006, largely due to pocket gopher herbivory. Oxalis albicans Talinum aurantiacum • The gentilis variety of Spidergrass is the only native grass that has increased significantly in OW since 2002.