Savannas, Barrens, and Rock Outcrop Plant Communities of North America

1999 ◽  
Keyword(s):  
North America ◽  
Plant Communities ◽  
Rock Outcrop

scholarly journals Pleistocene Megafaunal Collapse, Novel Plant Communities, and Enhanced Fire Regimes in North America

Science ◽  
2009 ◽  
Vol 326 (5956) ◽  
pp. 1100-1103 ◽  
Author(s):  
J. L. Gill ◽  
J. W. Williams ◽  
S. T. Jackson ◽  
K. B. Lininger ◽  
G. S. Robinson
Keyword(s):  
North America ◽  
Plant Communities ◽  
Fire Regimes

Introduction

2007 ◽  
Author(s):  
Earl B. Alexander ◽  
Roger G. Coleman ◽  
Todd Keeler-Wolfe ◽  
Susan P. Harrison
Keyword(s):  
North America ◽  
Plant Species ◽  
Plant Communities ◽  
Special Interest ◽  
Deep Understanding ◽  
Plant Evolution ◽  
Ultramafic Rocks ◽  
Serpentine Soils ◽  
Distinctive Features ◽  
Very High

Ultramafic, or colloquially “serpentine,” rocks and soils have dramatic effects on the vegetation that grows on them. Many plants cannot grow in serpentine soils, leaving distinctive suites of plants to occupy serpentine habitats. Plants that do grow on serpentine soils may be stunted, and plant distributions are commonly sparse relative to other soils in an area. Plant communities on serpentine soils are usually distinctive, even if one does not recognize the plant species. Because of these distinctive features, ultramafic rocks and serpentine soils are of special interest to all observers of landscapes. Geology underlies both conceptually and literally the distinctive vegetation on serpentine soils. The occurrence of special floras on particular substrates within particular regions makes rocks and soils of key significance to plant evolution and biogeography. Sophisticated interpretations of these interrelationships require a combined knowledge of geology, soils, and botany that few people possess. Even highly specialized professionals generally lack the requisite expertise in all three disciplines. The science of ecology, which in principle concerns interactions among all aspects of the environment, seldom incorporates a deep understanding of rocks and soils. Some scientists have attempted to bridge this gap through creating a discipline known as geoecology (Troll 1971, Huggett 1995), which forms the basis for our interdisciplinary exploration of serpentine rocks and soils in western North America. The term “serpentine” is applied in a general sense to all ultramafic rocks, soils developed from them, and plants growing on them. Ultramafic rocks are those with very high magnesium and iron concentrations. The word serpentine is derived from the Latin word serpentinus, meaning “resembling a serpent, or a serpent’s skin,” because many serpentine rocks have smooth surfaces mottled in shades of green to black. The distinctive chemistry of ultramafic rocks and serpentine soils restricts the growth of many plants and makes them refuges for plants that thrive in serpentine habitats, including serpentine endemics (species that are restricted to these soils) and other species that have evolved means of tolerating these habitats. Often the means of tolerance include visible adaptations such as slow growth and relatively thick, spiny foliage.

scholarly journals Endemic plants of the central grassland of North America: distribution, ecology, and conservation status

2017 ◽  
Vol 11 (1) ◽  
pp. 193-234
Author(s):  
James H. Locklear
Keyword(s):  
At Risk ◽  
North America ◽  
Biological Diversity ◽  
Conservation Status ◽  
Endemic Plants ◽  
Rock Outcrop ◽  
Conservation Action ◽  
Shrub Steppe ◽  
Llano Uplift ◽  
Centers Of Endemism

This paper enumerates the endemic plants of the Central Grassland of North America. The Central Grassland encompasses the full extent of the tallgrass, mixed-grass, and shortgrass prairie ecological systems of North America plus floristically related plant communities that adjoin and/or interdigitate with the midcontinental grasslands including savanna-open woodland systems, shrub-steppe, and rock outcrop communities. There are 382 plant taxa endemic to the Central Grassland, 300 endemic species (eight of which have multiple subspecific taxa endemic to the region) and 72 endemic subspecies/varieties of more widely distributed species. Nine regional concentrations of endemic taxa were identified and are described as centers of endemism for the Central Grassland: Arkansas Valley Barrens, Edwards Plateau, Llano Estacado Escarpments, Llano Uplift, Mescalero-Monahans Dunes, Niobrara-Platte Tablelands, Raton Tablelands, Red Bed Plains, and Reverchon Rocklands. In addition to hosting localized endemics, these areas are typically enriched with more widely-distributed Central Grassland endemics as well as peripheral or disjunct occurrences of locally-rare taxa, making them regions of high floristic diversity for the Central Grassland. Most of the endemics (299 or 78%) are habitat specialists, associated with rock outcrop, sand, hydric, or riparian habitats. There is a strong correlation between geology and endemism in the Central Grassland, with 59% of the endemics (225 taxa) associated with rock outcrop habitat. Of the 382 Central Grassland endemics, 124 or 33% are of conservation concern (NatureServe ranking of G1/T1 to G3/T3). Of these at-risk taxa, 78 or 63% are primarily associated with one of the centers of endemism identified in the study. It is hoped these findings will be useful in focusing conservation action on the habitats, ecological associations, and regions of the Central Grassland that host the highest concentrations of unique and at-risk plant species and associated biological diversity.

Sign in / Sign up

Export Citation Format

Share Document