Systematics of \u3cem\u3eGratiola\u3c/em\u3e (Plantaginaceae)

Gratiola (Plantaginaceae tribe Gratioleae) is a genus of ca. 33 wetland-adapted herbaceous species found mostly in temperate or tropical-montane regions of the Americas, Eurasia, and Australasia. The only worldwide taxonomic treatment of Gratiola was published more than 160 years ago and only a few representatives of the genus have been included in published molecular phylogenetic studies. The overall aim of this investigation was to provide a modern systematic study of Gratiola by determining the phylogenetic placement of Gratiola within the Gratioleae using chloroplast DNA sequence data (Chapter 2); examining the phylogenetic relationships, morphological character evolution, and biogeographical patterns within Gratiola using a combination of chloroplast DNA sequence data and morphology (Chapter 3); and conducting a taxonomic study of the Gratiola neglecta species complex, a group of four closely related and predominantly eastern North American species (Chapter 4). This dissertation is the accumulation of information from three original research papers. The first paper (Chapter 2) has been accepted for publication in Systematic Botany. The second paper (Chapter 3) will be submitted to Systematic Botany. The third paper (Chapter 4) has been published in the Journal of the Botanical Research Institute of Texas. The results from this study show (1) that Gratiola sensu lato (including Amphianthus, Fonkia, Sophronanthe, and Tragiola) is monophyletic and firmly embedded in a monophyletic Gratioleae and is sister to the Old World genera Hydrotriche and Limnophila; (2) that the 33 species (including four undescribed taxa) of Gratiola group into four major clades (Diandrae, Gratiola, Nibora, Sophronanthe) that are each morphologically cohesive and largely correspond to major biogeographic regions; and (3) that the Gratiola neglecta Complex includes four species (G. neglecta, G. floridana, G. graniticola, and G. quartermaniae), two of which constitute previously undescribed species that are morphologically and ecologically distinct

Population Dynamics and Angler Exploitation of the Unique Muskellunge Population in Shoepack Lake, Voyageurs National Park, Minnesota

A unique population of muskellunge Esox masquinongy inhabits Shoepack Lake in Voyageurs National Park, Minnesota. Little is known about its status, dynamics, and angler exploitation, and there is concern for the long-term viability of this population. We used intensive sampling and mark–recapture methods to quantify abundance, survival, growth, condition, age at maturity and fecundity and angler surveys to quantify angler pressure, catch rates, and exploitation. During our study, heavy rain washed out a dam constructed by beavers Castor canadensis which regulates the water level at the lake outlet, resulting in a nearly 50% reduction in surface area. We estimated a population size of 1,120 adult fish at the beginning of the study. No immediate reduction in population size was detected in response to the loss of lake area, although there was a gradual, but significant, decline in population size over the 2-year study. Adults grew less than 50 mm per year, and relative weight (W r) averaged roughly 80. Anglers were successful in catching, on average, two fish during a full day of angling, but harvest was negligible. Shoepack Lake muskellunge exhibit much slower growth rates and lower condition, but much higher densities and angler catch per unit effort (CPUE), than other muskellunge populations. The unique nature, limited distribution, and location of this population in a national park require special consideration for management. The results of this study provide the basis for assessing the long-term viability of the Shoepack Lake muskellunge population through simulations of long-term population dynamics and genetically effective population size