Stochastic Processes during Invasion: The Influence of Population Size on Style-Morph Frequency Variation in Lythrum salicaria (Purple Loosestrife)

2016 ◽  
Vol 177 (5) ◽  
pp. 409-418 ◽  
Author(s):  
Christopher M. Balogh ◽  
Spencer C. H. Barrett
Keyword(s):  
Stochastic Processes ◽  
Population Size ◽  
Lythrum Salicaria ◽  
Purple Loosestrife ◽  
Frequency Variation ◽  
Morph Frequency

Morph frequencies and floral variation in a heterostylous colonizing weed, Lythtum salicaria

1997 ◽  
Vol 75 (7) ◽  
pp. 1034-1045 ◽  
Author(s):  
Tarun K. Mal ◽  
Jon Lovett-Doust
Keyword(s):  
Clonal Growth ◽  
Significant Interaction ◽  
Spatial Separation ◽  
Lythrum Salicaria ◽  
Purple Loosestrife ◽  
Frequency Of Occurrence ◽  
Floral Variation ◽  
Morphometric Analyses ◽  
Herbaceous Perennial ◽  
Morph Frequency

Lythrum salicaria (purple loosestrife) is an exotic weed that arrived in North America from Europe during the early 1800s. It is a herbaceous perennial with a trimorphic breeding system. Seventy-four populations of L. salicaria were surveyed from Windsor, Ontario, to the Gaspé Peninsula in Quebec. Fifty of the populations were significantly anisoplethic (i.e., unequal frequencies of the three flower morphs), including 10 populations that were nontrimorphic. Populations with fewer than 100 plants tended to have one or even two morphs missing. Although larger populations rarely lacked a morph, they did show significantly skewed morph frequencies. Indices of clonal size, such as number of ramets per genet and genet diameter, differed significantly among sites, and clonal growth also showed significant interaction between morph and site. One-way analyses of variance indicated that morphs differed in terms of either number of ramets per genet or genet diameter in 16% of populations. Morphometric analyses of flowers from 49 populations showed significant variability in floral traits among genets, flower morphs, and sites. Results indicated frequent reduction in herkogamy (spatial separation between anther and stigma), with variant flowers having very little or no stigma–anther separation. Mean stigma–anther separation was lowest in the mid-morph individuals, followed by the short and long morphs. Correspondingly, the frequency of variant flowers was greatest in mid-morph individuals and least in long-morph individuals. Isoplethic and anisoplethic populations did not differ, for any morph, in the frequency of occurrence of these variant flowers. Key words: Lythrum salicaria, purple loosestrife, isoplethy, morph frequency, heterostyly, variant flowers, stigma–anther separation.

Effect ofGalerucellaspp. on survival of purple loosestrife (Lythrum salicaria) roots and crowns

Weed Science ◽  
1999 ◽  
Vol 47 (3) ◽  
pp. 360-365 ◽  
Author(s):  
Elizabeth J. Stamm Katovich ◽  
Roger L. Becker ◽  
David W. Ragsdale
Keyword(s):  
Plant Stress ◽  
Growing Season ◽  
Lythrum Salicaria ◽  
Purple Loosestrife ◽  
Biological Control Agents ◽  
Plant Mortality ◽  
Galerucella Calmariensis ◽  
Galerucella Pusilla ◽  
Crown Tissue ◽  
Severe Leaf

Starch levels, used as a measure of plant stress, were not consistently reduced in root or crown tissue of purple loosestrife plants after 2 yr of severeGalerucella calmariensisorGalerucella pusilla(Coleoptera: Chrysomelidae) defoliation. Early in the season, defoliation fromGalerucellaspp. approached 100%, but the majority ofLythrum salicariaplants regrew by the end of August, resulting in an average reduction of 81% of the aboveground biomass compared to the control. The stress imposed byGalerucellaspp. defoliation was less than that achieved from more severe stress imposed by mechanical shoot clipping at 2- or 4-wk intervals from June to October. Both shoot-clipping treatments killed the majority of plants after one growing season.Galerucellaspp. feeding reduced plant stature, which may reduce competitiveness. However, considering the extensive carbohydrate reserves present in the large woody crowns ofLythrum salicaria, it will require in excess of 2 yr of consistent, severe leaf defoliation to cause plant mortality. A combination of stresses, such as winter crown injury, or other biological control agents in addition toGalerucellaleaf defoliation may be required for plant mortality.

Influence of Nontarget Neighbors and Spray Volume on Retention and Efficacy of Triclopyr in Purple Loosestrife (Lythrum salicaria)

Weed Science ◽  
1996 ◽  
Vol 44 (1) ◽  
pp. 143-147 ◽  
Author(s):  
Elizabeth J. Stamm Katovich ◽  
Roger L. Becker ◽  
Brad D. Kinkaid
Keyword(s):  
Plant Density ◽  
Spray Deposition ◽  
Soil Surface ◽  
Lythrum Salicaria ◽  
Purple Loosestrife ◽  
Central Target ◽  
Basal Portion ◽  
Spray Volume ◽  
Vegetative Propagules ◽  
Target Plant

Greenhouse studies were conducted to determine the influence of plant density and spray volume on the retention, spray deposition, efficacy, and translocation of the amine salt of triclopyr in purple loosestrife. More spray solution was retained on leaves at 935 Lha−1than at 94 Lha−1at populations of 0, 4, or 8 nontarget neighbors. Spray coverage decreased with decreasing height within the plant canopy when spray cards were placed in the top, middle, and soil surface adjacent to the central target plant. Within a population, spray card coverage generally increased as spray volume increased. Regrowth from the crown was affected by spray volume, and uniform spray coverage of the plant was required for adequate control of vegetative regrowth and was achieved with spray volumes of 374 and 935 L ha−1spray volume. Regrowth of purple loosestrife was greater at 94 Lha−1at all three plant populations indicating that less herbicide penetrated the canopy to reach the basal portion of the plant. A laboratory experiment was conducted to investigate the translocation of radiolabelled triclopyr to roots and crowns of purple loosestrife. Only 0.3 to 1.4% of absorbed14C-labelled material was translocated to roots and crowns. Low spray volumes and dense stands of purple loosestrife would likely result in poor control because inadequate amounts of triclopyr reach the basal portion of the plant and translocate to vegetative propagules.

Variation in floral morph ratios in tristylous Oxalis squamata (Oxalidaceae): an Andean alpine endemic

Botany ◽  
2012 ◽  
Vol 90 (11) ◽  
pp. 1180-1185 ◽  
Author(s):  
Spencer C.H. Barrett ◽  
Mary T.K. Arroyo
Keyword(s):  
Clonal Propagation ◽  
Frequency Variation ◽  
Significant Heterogeneity ◽  
Approach To Equilibrium ◽  
Central Chile ◽  
Large Populations ◽  
Negative Frequency Dependent Selection ◽  
Morph Ratios ◽  
Floral Morph ◽  
Morph Frequency

Negative frequency-dependent selection resulting from disassortative mating should result in equal morph ratios in tristylous populations at equilibrium. However, surveys of morph-frequency variation in tristylous species commonly report deviations from equality. Here, we report variation in morph ratios in Oxalis squamata Zucc., an endemic of the Andean region of Chile and Argentina. Absence of clonal propagation in this species allows unambiguous estimates of the morph ratio of genets. We sampled floral morph ratios in 20 populations occurring in Central Chile and investigated the relation between morph evenness in populations and their size. All populations of O. squamata were tristylous but with significant heterogeneity among populations in morph ratios. Although small populations exhibited a greater variance in morph evenness, biased ratios were also evident in several large populations. We found no evidence of morph loss or a consistent bias in morph frequencies as reported in some tristylous species. Biased morph frequencies in large populations probably arise from episodic sexual recruitment following disturbance and a slow approach to equilibrium.

Winter survival of late emerging purple loosestrife (Lythrum salicaria) seedlings

Weed Science ◽  
2003 ◽  
Vol 51 (4) ◽  
pp. 565-568 ◽  
Author(s):  
Elizabeth J. Stamm Katovich ◽  
Roger L. Becker ◽  
Jane L. Byron
Keyword(s):  
Lythrum Salicaria ◽  
Winter Survival ◽  
Purple Loosestrife

Isozyme characterization of genetic diversity in Minnesota populations of purple loosestrife,Lythrum salicaria(lythraceae)

1996 ◽  
Vol 83 (3) ◽  
pp. 265-273 ◽  
Author(s):  
Mark S. Strefeler ◽  
Elizabeth Darmo ◽  
Roger L. Becker ◽  
Elizabeth J. Katovich
Keyword(s):  
Genetic Diversity ◽  
Lythrum Salicaria ◽  
Purple Loosestrife

The Biology and Management of Purple Loosestrife (Lythrum salicaria)

1998 ◽  
Vol 12 (2) ◽  
pp. 397-401 ◽  
Author(s):  
Barbra H. Mullin
Keyword(s):  
Large Scale ◽  
Management Practices ◽  
Habitat Degradation ◽  
Control Measure ◽  
Management Strategies ◽  
Lythrum Salicaria ◽  
Wildlife Habitat ◽  
Purple Loosestrife ◽  
Riparian Areas ◽  
Wetland Ecosystems

Purple loosestrife is an invasive, introduced plant that is usually associated with wetland, marshy, or riparian sites. It is found across the northern tier states and provinces in North America. Purple loosestrife affects the diversity of native wetland ecosystems. Infestations lead to severe wildlife habitat degradation, loss of species diversity, and displacement of wildlife-supporting native vegetation, such as cattails and bulrushes. The plant spreads effectively along waterways, and the thick, matted root system can rapidly clog irrigation ditches, resulting in decreased water flow and increased maintenance. Effective management of purple loosestrife along waterways and in riparian areas requires integrating management strategies to prevent further introductions, detecting and eradicating new infestations, and containing and controlling large-scale infestations. Management practices that aid in the control of purple loosestrife include herbicide, physical, and biological practices. Each infestation site should be individually evaluated to determine the appropriate control measure. Factors to be considered include the proximity and type of vegetation on the site, whether the water is flowing or still, and the utilization of the site and the water (domestic, irrigation, recreation, or scenic value).

Sign in / Sign up

Export Citation Format

Share Document