The Spanish and Mexican Baseline of California Tree and Shrubland Distributions Since the Late 18Th Century

Aliso: A Journal of Systematic and Evolutionary Botany Volume 33 | Issue 1 Article 4 2015 The pS anish and Mexican Baseline of California Tree and Shrubland Distributions Since the Late 18th Century Richard A. Minnich University of California, Riverside Brett R. Goforth California State University, San Bernardino Richard Minnich Dept. of Earth Sciences, University of California, Riverside, [email protected] Follow this and additional works at: http://scholarship.claremont.edu/aliso Part of the Botany Commons, and the Forest Sciences Commons Recommended Citation Minnich, Richard A.; Goforth, Brett R.; and Minnich, Richard (2015) "The pS anish and Mexican Baseline of California Tree and Shrubland Distributions Since the Late 18th Century," Aliso: A Journal of Systematic and Evolutionary Botany: Vol. 33: Iss. 1, Article 4. Available at: http://scholarship.claremont.edu/aliso/vol33/iss1/4 Aliso, 33(1), pp. 5–76 ISSN 0065-6275 (print), 2327-2929 (online) THE SPANISH AND MEXICAN BASELINE OF CALIFORNIA TREE AND SHRUBLAND DISTRIBUTIONS SINCE THE LATE 18TH CENTURY RICHARD A. MINNICH1,3 AND BRETT R. GOFORTH2 1Department of Earth Sciences, University of California, Riverside, California 92521; 2Department of Geography and Environmental Studies, California State University, San Bernardino, California 92407 3Corresponding author ([email protected]) ABSTRACT Historical distributions of 31 tree species, chaparral, and coastal sage scrub described by Spanish land explorers in the late eighteenth and early nineteenth centuries (1769–1806) and in land grant disenõs (1784– 1846) are reconstructed at 634 localities across central and southern California. This baseline predates most formal botanical surveys by nearly a century, allowing for assessment of vegetation change over the broadest time frame for comparison with pre-historical evidences and future distributions. Spanish accounts are compared with historical sources in the Mexican era (1821–1848), American settlement (1848– 1929), and modern range maps of the 1929–1934 Vegetation Type Map (VTM) survey. Among tree species that were recorded in Spanish explorations, the site-specific localities are consistent with VTM maps at the spatial resolution of the land expeditions. In contrast with massive deforestation across eastern North America since European colonization, hardwood and conifer forests in California sustained inconsequen- tial cutting during Hispanic settlement. Spanish accounts and Mexican disenõs occasionally provide remarkable detail of fine-scale distributions which have not changed over the past two centuries, including Pinus radiata forest at Cambria and Monterey, the eastern limit of Quercus lobata and Q. agrifolia woodlands with Aesculus californica in the Salinas Valley, as well as isolated stands of Cupressus macrocarpa and C. sargentii. Disjunct occurrences of trees in southern California were recorded at the same places they occur today, including an isolated grove of Q. engelmannii at the Baldwin Park Arboretum, and the Pinus coulteri stand in the mountains above Santa Barbara. The southern margin of mixed conifer forest in the San Bernardino Mountains has remained on the crest of the range since Garce´s’ account in 1776. Long-term tree distributions are evaluated with respect to land use, grazing and climate change. We advocate the use of historical records as proxy data for climate change studies. Key words: California trees, chaparral, coastal sage scrub, Geographical Information Systems, Google Earth, plant geography, species ranges, vegetation change, vegetation history, vegetation type map. INTRODUCTION influences the amount of change that can be detected, i.e., the “shifting baseline syndrome” in ecological studies (Jackson et al. To map changes in vegetation distributions at broad 2001). The story you tell depends on when you start the story. temporal and spatial scales it is necessary to designate In California—the coastal region from the U.S.-Baja a “baseline” of historical records for comparison to extant California Mexico boundary to San Francisco settled in the ranges. In long-lived forest and shrubland ecosystems, species Spanish (1769–1821) and Mexican eras (1821–1848)—a central change is slow and often emerges only when compared with question is the extent to which the natural vegetation was documentation that predates formal scientific study. Inevita- modified since the onset of Spanish colonization in 1769. bly, such documentation lacks precision of observations Previous studies have reconstructed profound change in (Minnich and Franco-Vizcaıńo 1998; Jackson et al. 2001; California herbaceous ecosystems with the displacement of Minnich 2008): historical documentary records are limited to written accounts of land explorations and settlers, as well as indigenous wildflower fields by exotic annual grasses and forbs cadastral surveys, newspaper accounts, and early photographs. introduced from Mediterranean Europe and the Middle East, Observers also lacked precise methods of field survey gained by a transformation whose onset predates the first scientific modern scientific protocols and taxonomic nomenclature. surveys of the region (Huenneke 1989; D’Antonio and Consequently, a large body of records is needed because Vitousek 1992; Sims and Risser 2000; Minnich 2008). individual sources typically provide observations incidental to California was first described in brief encounters during the the study of vegetation. Records are especially informative at Cabrillo (1542) and Vizcaıńo voyages (1602) (Minnich 2008: fixed locations that can be traced through time (Grove and 10). Cabrillo sailed northward from Navidad, Mexico, and Rackham 2001). The choice of historical reference also kept within sight of shore along Baja California and southern California. Vizcaıńo also explored the coast of Baja California and southern California and discovered the Bay of San Diego and Monterey. Both expeditions left rare, mostly cursory, ’ 2015. The Author(s). CC-BY. This open access article is accounts of vegetation (Bolton 1916). The earliest comprehen- distributed under a Creative Commons Attribution License, which allows unrestricted use, distribution, and reproduction in any medium, sive historical baseline of vegetation is the record of late provided that the original author(s) and source are credited. Articles eighteenth century Spanish land explorations by Franciscan can be downloaded at http://scholarship.claremont.edu/aliso/. missionaries and soldiers. By 1772, missions were already being 6 Minnich and Goforth ALISO established between San Diego and San Francisco, but allowing the identification of many common plants to modern missionaries concluded they had insufficient manpower to species (Minnich 2008: 298–302).2 In many cases plant establish missions in northern Baja California (Minnich 2008: descriptions could be interpreted to species level because only 13). A “concordat” was made between the Franciscan and one member of the genus is known at the site of observation. Dominican orders. The Dominicans agreed to take over the Another primary source in the Spanish and Mexican eras Jesuit mission system in the deserts of Baja California, and to are disenõs, or sketch maps of land grants across the coastal establish new missions in Mediterranean lands of northern Baja plains and valleys of California. Disenõs were submitted as California. The Franciscans would control the mission system part of a petition submitted to the Governor of California to in Alta California. The concordat eventually became the basis obtain land-grant concessions (Becker 1964; Cleland 1964; for the division of Baja California, Mexico, from California. Hornbeck 1983). We examined 638 disenõs archived in the This study examines records of tree species’ localities given California State Library.3 Their basic annotations include in the expedition journals of Portola´ (1769–1770, 1772), Anza a scale and north arrow, the boundaries of adjoining land- (1774, 1776) and Paloú (1774) for coastal southern and central grants, and the location of a ranch house. Most include names California (Brown 2001; Bolton 1908, 1911, 1926, 1927, 1930, of regional landmark features like roads, rivers, and mountains 1931, 1933; CATE 2014; routes shown in Fig. 1). These in the area. About 10% of disenõs give plant names. Since the sources provide a large dataset of tree species localities used to maps are impressionistic rather than planimetric, localities of test for changes in distribution. We also examine the Zalvidea plant names can be resolved only to the scale of the land grant (1805) and Moraga (1806) expeditions into the great central itself.4 Most disenõs describe areas of quality pasture for cattle valley, still unsettled by Spanish colonists at that time (Cook grazing near the coast, with symbols and Spanish plant names 1960, 1962). We review untranslated Spanish accounts as for trees occurring on the land grant (Minnich 2008: 90). Rare primary sources of information to establish the vocabulary of land grants in the interior central valley were described as species or plant assemblages, which on occasion have been “barrens,” evidently for lack of feed to support herds of cattle. erroneously translated (e.g., Minnich 2008: 26–28). These During the American settlement period, formal surveys of accounts, as well as those of later Mexican, European and California lands, including botany and vegetation, were American settlers in the nineteenth century, describe vegeta- conducted by

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