Roger Rosentreter

Biological Soil Crusts of North America

Biological soil crusts in North America are diverse and found in many different habitats. On a broad scale, there are several different vegetation zones or ecoregions in western North America that contain biological soil crusts as major components (Fig. 2.1, Table 2.1). These include hot deserts (Mojave, Chihuahuan, Sonoran; see Chap. 1, Photos 34, 35), cool deserts (Great Basin, Colorado Plateau; also often denoted as semideserts, Photos 29–33), the coastal woodlands, chaparral and islands of California; and the subhumid grasslands of the Great Plains. These habitats span a large range of annual precipitation (75–740 mm) and annual mean temperatures (4–24°C). Soil crusts are also found on a smaller scale in shallow lithic sites, infertile forest soils, alpine habitats, and more mesic ecosystems as an early successional vegetation type.

Lichens as Nesting Material for Northern Flying Squirrels in the Northern Rocky Mountains

We examined the composition of nest material used by northern flying squirrels ( Glaucomys sabrinus ) occupying artificial nest boxes in central Idaho and western Montana. Nests were constructed almost entirely of arboreal lichens (96% lichen by volume). In both regions, three species of Bryoria dominated nesting material although a total of 15 species of lichens were identified in 159 nest samples from central Idaho. Species of lichens used for nests differed across four types of forest vegetation. Nests in stands of lodgepole pine ( Pinus contortd ) had more Bryoria fremontii and less B. pseudofuscescens than nests in other forest types. The rank-order abundance of lichens used in nests was related to the rank-order abundance of lichens collected from forests at nest sites, although the relationship was not strong. We suggest that lichen nests may function to reduce thermal energy expenditures during winter or act as food caches. The dominant lichen used in nests lacked acids and other secondary compounds found in other arboreal lichens and, thus, may be more palatable to squirrels.

Recovery of biological soil crusts following wildfire in Idaho

Abstract Invasion of sagebrush steppe by exotic annual grasses has modified the structure of shrubland communities over much of the western United States by increasing fuel loads and therefore the frequency of wildfire. Active revegetation with perennial species that encourage the growth of biological soil crusts is critical on many burned sites to prevent dominance by exotic, weedy vegetation. However, active regeneration is likely to lead to a disruption of the soil surface and impact adversely on soil crust communities which are important for stability and functioning of shrub communities. We examined the recovery of biological soil crusts on sagebrush steppe following wildfire. Burning resulted in significantly reduced shrub cover and enhanced annual grass and annual forb cover compared with unburned sites. Burning also resulted in substantially reduced diversity and richness of crust taxa, increased cover of short mosses, but reduced cover of lichens and tall mosses growing on the shrub hummocks. Post-fire recovery of perennial grasses and biological soil crusts was greatest on seeded sites compared with unseeded sites dominated by exotic grasses, despite the disturbance associated with the rangeland seeding treatment. Our results indicate that seeding is necessary to facilitate recovery of biological soil crusts and hasten the development of the perennial component of the shrubland and therefore increase landscape structure. These findings suggest that seeding perennial grasses and resting from livestock grazing reduces exotic annual grasses after fire and benefits native mosses.

Vagrant Lichens in North America

Vagrant lichen taxa are presently recognized in several genera. Xanthoparmelia con- tains the largest number of vagrant taxa and is the most widely distributed geographically, with vagrant taxa represented in several habitats in North America and other continents. Aspicilia has the second largest number of vagrant taxa worldwide, including A. fruticulosa (Eversm.) Flagey, reported new for North America from Idaho, Montana, Oregon, Utah, and Wyoming. Habitat supporting vagrant lichens is typically windswept, semi-arid, and sparsely vegetated. In some areas attached, erratic, and vagrant taxa of Rhizoplaca occur sympatrically. Environmentally modified erratic forms of attached taxa of Dermatocarpon, Lecanora, and Umbilicaria occur in habitats occupied by vagrant taxa. Reproduction in vagrant lichens is typically by large unspecialized veg- etative fragments. Due to widescale land disturbance, livestock grazing, and the dispersal strategies of vagrant lichens, some taxa are so fragmented in their distribution that they may become extinct.

Notes on the Lichens and Allied Fungi of British Columbia. II

Based on field studies and herbarium research, 46 species of lichens and lichenicolous fungi are reported new to British Columbia. The following 15 species are documented for Canada for the first time: Agonimia tristicula, Catapyrenium daedaleum, Cladonia luteoalba, Collema auriforme, Dactylospora lobariella, Fulgensia desertorum, Massalongia microphylliza, Pannaria ahlneri, Peltula euploca, Physcia callosa, Psora montana, Sticta wrightii, Usnea wirthii, Vester- grenopsis elaeina, and Xanthoparmelia planilobata. An additional nine species are new to North America north ofMexico: Acroscyphus sphaerophoroides, Biatoropsis usnearum, Hawksworthiana peltigericola, Leptogium brebissonii, L. schraderi, Lichenochora thallina, Scutula miliaris, Sphae- rellothecium araneosum, and Trapelia corticola.

Burning and Seeding Influence Soil Surface Morphology in an Artemisia Shrubland in Southern Idaho

We compared the morphology of soil surfaces dominated by Wyoming big sagebrush at burned-seeded, burned-unseeded, and unburned sites in southern Idaho. Both burning and seeding resulted in significant changes in soil surface morphology. Unburned sites were dominated by Type I (shrub- and grass tussock-dominant coppice) and Type II (lichen- and moss-covered coppice bench)surfaces, while burned-seeded sites were dominated by Types I, II, and III (bare or lichen-covered microplains between the individual coppices) surfaces. Type V surfaces (severely-disturbed, annual grass-dominant microsites) predominated on the burned-unseeded sites. Burning and subsequent conversion of native shrubland to exotic grassland results in a predominance of Type V surfaces unless seeding is used to reintroduce perennials or the surface is allowed to recover in the absence of subsequent fire and disturbance. The benefits of postfire revegetation and subsequent recovery of soil surfaces conducive to germination and establishment of perennial grass and shrub communities outweigh the initial short-term disturbance associated with drill seeding.

Texosporium sancti-jacobi, a Rare Western North American Lichen

The lichen Texosporium sancti-jacobi (Ascomycetes: Caliciales) is known from only four general locations worldwide, all in western U.S.A. Typical habitat of Texosporium has the following characteristics: arid or semiarid climate; nearly flat ground; noncalcareous, nonsaline, fine- or coarse-textured soils developed on noncalcareous parent materials; little evidence of recent disturbance; sparse vascular plant vegetation; and dominance by native plant species. Within these constraints Texosporium occurs on restricted microsites: partly decomposed small mammal dung or organic matter infused with soil. The major threat to long-term survival of Texosporium is loss of habitat by extensive destruction of the soil crust by overgrazing, invasion of weedy annual grasses and resulting increases in fire frequency, and conversion of rangelands to agriculture and suburban developments. Habitat protection efforts are important to perpetuate this species. The lichen Texosporium sancti-jacobi (Tuck.) Nadv. is globally ranked (conservation status G2) by the United States Rare Lichen Project (S. K. Pittam 1990, pers. comm.). A rating of G2 means that globally the species is very rare, and that the United States Rare Lichen Project maintains a file on the species, notifies local governmental jurisdic- tions of occurrences, and, as warranted, seeks listing on the U.S. Fish and Wildlife Service Threatened

Vagrant Dermatocarpon in Western North America

Dermatocarpon miniatum (L.) Mann and D. reticulatum Magn. have vagrant forms with the gross morphology of D. vagans Imsh. Dermatocarpon vagans is not a distinct species. Rather, it is an environmental modification of D. reticulatum. Optimum habitat for vagrant Der- matocarpon in the western United States has the following characteristics: mostly flat, exposed areas with sparse vegetation; thin rocky basalt soils; seasonal shallow ponding; and a climate with hot dry summers and cold winters. Several lichen genera contain both attached and unattached (vagrant) forms. The most prominent of these genera in arid and semiarid regions of North America and Eurasia are Aspicilia, Dermatocarpon, Rhizoplaca, and Xanthoparmelia. Distinct vagrant species are presently recognized in all of these gen- era. The validity of several of these taxa has been questioned (Weber 1967, 1977). As more free-living material is collected in these genera, the distinctness of the vagrant species needs to be reexamined. In some cases, e.g., Rhizoplaca, more study is likely to lead to more, rather than fewer, vagrant species. A single vagrant species, D. vagans Imsh., has been described in the genus Dermatocarpon (Im- shaug 1950). In outward form it is unlike all other Dermatocarpon, having tightly rolled lobes and a three-dimensional habit. This taxon has been re- ported from only two sites apart from the type lo- cality (Eversman 1990; Imshaug 1950). Additional collecting on the basalt plains and plateaus between the Rocky Mountains and the Cascade Range re- vealed that this growth form is locally common, but restricted to an unusual habitat. Furthermore, va- grant forms co-occur with more typical, nonvagrant Dermatocarpon species. We sought to determine whether this taxon represents a distinct species or whether it is an environmental modification of the more common, sympatric Dermatocarpon species.

Effect of Ozone on the Lichen Cladonia arbuscula and the Trebouxia Phycobiont of Cladina stellaris

The chlorophyll content of Cladonia arbuscula (Wallr.) Rabenh. thalli and of a Trebouxia phycobiont isolated from Cladina stellaris (Opiz) Brodo increased after the organisms were exposed for one week to an ozone concentration of 0.1 ppm. Concentrations of ozone above 0.1 ppm did not significantly affect the chlorophyll content relative to those of the controls. There were no discernible morphological effects that could be attributed to

Monitoring Biodiversity and Ecosystem Function: Grasslands, Deserts, and Steppe

During the past century, land managers have grappled with methods to assess both the condition (health) and degree of change (trend) of arid landscapes [77]. Traditional approaches have focused on the documentation of various attributes of vascular plant communities [34]. More recently however, Australian and American researchers have incorporated data on biological soil crust taxa (lichens, bryophytes and cyanobacteria) in condition and trend assessment of arid lands (rangelands) [32, 57, 78, 80] principally due to the growing recognition that these organisms are critical for rangeland stability. In this chapter, “rangelands” refers to landscapes or vegetation communities which are dominated by native vegetation, are used predominantly for grazing, recreation or traditional ownership (e.g. aboriginal occupation or transhumance), but excludes commercial non-native forests or areas of intensive agriculture. Lichens of native forests are discussed in Will-Wolf et al. (chapter 14, this volume).