Supporting Spartina: Interdisciplinary perspective shows Spartina as a distinct solid genus

In 2014 a DNA-based phylogenetic study confirming the paraphyly of the grass subtribe Sporobolinae proposed the creation of a large monophyletic genus Sporobolus, including (among others) species previously included in the genera Spartina, Calamovilfa, and Sporobolus. Spartina species have contributed substantially (and continue contributing) to our knowledge in multiple disciplines, including ecology, evolutionary biology, molecular biology, biogeography, experimental ecology, environmental management, restoration ecology, history, economics, and sociology. There is no rationale so compelling to subsume the name Spartina as a subgenus that could rival the striking, global iconic history and use of the name Spartina for over 200 years. We do not agree with the arguments underlying the proposal to change Spartina to Sporobolus. We understand the importance of taxonomy and of formalized nomenclature and hope that by opening this debate we will encourage positive feedback that will strengthen taxonomic decisions with an interdisciplinary perspective. We consider the strongly distinct, monophyletic clade Spartina should simply and efficiently be treated as the genus Spartina

Explaining the explosion: modelling hybrid invasions

The emergence of hybrids between native and introduced species is an increasingly widespread problem which can alter entire ecosystems. We present a general model for the hybridization of two plant species to investigate the conditions under which hybrid invasions can occur, and the ecological and genetic consequences of such hybridizations. We find that parental compatibility and fecundity are important determinants of whether (and at what rate) hybrid genotypes emerge. Enhanced hybrid fitness traits affect both the population's genetic structure and total rate of increase, with rapid selection for the fittest genotype. Conversely, if different genotypes maximize different life-history characteristics, the ensuing population can be genetically very variable. The model provides a novel approach to evaluate the contributions of population dynamic and genetic processes in the study of hybrid invasions

Vegetation and Flora of A Biodiversity Hotspot: Pine Hill, El Dorado County, California, USA

Volume: 56Start Page: 246End Page: 27

Effects of a firebreak on plants and wildlife at Pine Hill, a biodiversity hotspot, El Dorado County, California

We examined the effects of hand clearing and pile burning of chaparral on plants and wildlife on the perimeter of Pine Hill 1–2 years after clearing. Pine Hill is home to four federally listed plant species, necessitating botanical surveys prior to clearing activities to prevent harming these species. We found over 65 new locations for the listed plants. We compared vegetation within burn scars, in cleared only plots, and in intact chaparral (control) and the germination and survival of a listed species, Ceanothus roderickii (Pine Hill Ceanothus). The density of C. roderickii seedlings was far lower in the cleared, unburned treatment than in the burned treatments, while mature C. roderickii was only present in unburned treatments and mature chaparral. Intact chaparral had higher cover but lower species richness of both native and exotic species than all disturbed treatments. The cleared only treatment had almost three times the cover by exotic grasses as did the burned treatments, and cover by presumably palatable, native and exotic species, was almost twice that of the burned treatments; mature chaparral contained few palatable plants, i.e. those identified as having wildlife value by Conrad (1987). Increased availability of palatable plants in treated areas may have contributed to 3–4 times higher probabilities of detection by cameras of herbivores in treated versus intact chaparral; which may have attracted smaller predators (bobcats [Lynx rufus] and gray foxes [Urocyon cinereoargenteus]) that were positively associated with western grey squirrel (Sciurus griseus) detections. Large carnivore detections were higher in areas with higher mule deer (Odocoileus hemionus) detections. Larger animals (pumas [Puma concolor], black bears [Ursus americanus], and mule deer) were detected 2–4 times more in treated areas, likely due to the physical impediment of mature chaparral. Invasion of nonnative grasses and increased wildlife usage may have been accelerated through the creation of firebreaks; continued monitoring will investigate long-term effects

Evolution of a new ecotype of Spartina Alterniflora (Poaceae) in San Francisco Bay, California, USA

We report the discovery and spread of a dwarf ecotype of Spartina alterniflora in San Francisco Bay. Relative to typical S. alterniflora, this dwarf ecotype has one-fifth the tiller height (~21 cm), tenfold the tiller density (~4000 tillers/m²), and is restricted to growth in the upper intertidal zone. Chromosome counts of the dwarfs are identical to typical smooth cordgrass (2n = 62), and smooth cordgrass-specific random amplified DNA markers confirm the species identity of the dwarf. Field-collected clonal fragments of the dwarf grown for 2 yr under high-nutrient conditions maintained the dwarf syndrome, as did plants grown from the seed of a dwarf. The dwarf condition is not caused by endophytic fungi. The first dwarf smooth cordgrass patch was discovered in 1991, and by 1996 five separate dwarf patches had appeared within 200 m of the original. Since 1991, total area covered by the dwarf ecotype has increased sixfold to 140 m². The ecological range of the dwarf smooth cordgrass ecotype is similar to that of S. patens, a competitor on the Atlantic coast. We suggest that the absence of S. patens from most of San Francisco Bay has allowed the dwarf ecotype of smooth cordgrass to survive and spread