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Norman C. Ellstrand - One of the best experts on this subject based on the ideXlab platform.

  • nonlocal transplantation and outbreeding depression in the Subshrub lotus scoparius fabaceae
    American Journal of Botany, 2001
    Co-Authors: Alicia M. Montalvo, Norman C. Ellstrand
    Abstract:

    The genetic background of transplants used to create or augment wild populations may affect the long-term success of restored populations. If seed sources are from differently adapted populations, then the relative performance of progeny from crosses among populations may decrease with an increase in genetic differences of parents and in the differences of parental environments to the transplant location. We evaluated the potential for such outbreeding depression by hybridizing individuals from six different populations of Lotus scoparius var. scoparius and L. s. var. brevialatus. We used allozyme data to calculate genetic distances between source populations, and compiled climatic data and measured soil traits to estimate environmental distances between source populations. We found significant outbreeding depression following controlled crosses. In the greenhouse, the success of crosses (seeds/flower 3 seedlings/seed) decreased with increasing genetic distance between populations revealing genetically based outbreeding depression unrelated to local adaptation. After outplanting to one native site (in situ common garden), field cumulative fitness of progeny (survival 3 fruit production) decreased significantly with mean environmental distance of the parental populations to the transplant site, but not with genetic distance between the crossed populations. This result is consistent with a disruption of local adaptation. At the second, ecologically contrasting common garden, where low survival reduced statistical power, field cumulative fitness (survival3 progeny height) did not decrease significantly with either environmental distance or genetic distance. Overall, intervariety crosses were 40 and 50% as fit (seeds/flower 3 seedlings/seed 3 survival 3 fruits at the first garden or 3 height at the second) as intravariety crosses. These results suggest that the cumulative outbreeding depression was caused by a combination of genetically based ecological differences among populations and other genomic coadaptation. We conclude that mixing genetically differentiated seed sources of Lotus scoparius may significantly lower the fitness of augmented or restored populations. Genetic and environmental similarities of source populations relative to the transplant site should be considered when choosing source materials, a practice recommended by recent seed transfer policies. Geographic separation was not a good surrogate for either of these measures.

  • transplantation of the Subshrub lotus scoparius testing the home site advantage hypothesis
    Conservation Biology, 2000
    Co-Authors: Arlee M Montalvo, Norman C. Ellstrand
    Abstract:

    : The long-term success of restored populations may be jeopardized by the collection locality of transplants if they are ill matched to their new environment. The home-site advantage hypothesis predicts that the relative success of introduced populations will decrease as their genetic and environmental distance to the local native population increases. We evaluated this hypothesis for a geographically variable shrub, Lotus scoparius, in southern Californian coastal sage scrub by planting two common-garden experiments with seedlings from 12 source populations. The common-garden sites differed in environment and were each home to different source populations of the two taxonomic varieties, L. s. var. scoparius or L. s. var. brevialatus. We used allozyme data from each source population to calculate genetic distances between populations, and a combination of climatic data and soil traits to calculate environmental distances. At the more mesic, coastal common garden, cumulative fitness of transplants (survival × flower production) was inversely related to genetic distance between source and resident populations. At the more xeric, inland common garden, cumulative fitness (survival × size) decreased significantly with both genetic and environmental distance after one taxonomic variety was excluded from analyses. Geographic distance was only weakly correlated with genetic distance and had little value in predicting cumulative fitness of transplants. Our data support the home-site advantage hypothesis and the idea that mis-matching source populations of these genetically differentiated seed sources may result in lowered success of restored or constructed populations. The genetic and environmental similarities of source populations should be considered when source materials are chosen for transplantation. Resumen: El exito a largo plazo de poblaciones restauradas puede ser expuesto a riesgos por la localizacion de la colecta de transplantes si estos no corresponden adecuadamente a su nuevo ambiente. La hipotesis sobre las ventajas de la ubicacion del hogar predice que el exito relativo de poblaciones introducidas decrecera al incrementarse su distancia genetica y ambiental de la poblacion nativa local. Evaluamos esta hipotesis para un arbusto geograficamente variable, Lotus scoparius, en el matorral de salvia costero del sur de California, sembrado en dos experimentos en jardines comunes con plantulas de 12 poblaciones fuente. Los sitios de jardines comunes difirieron en ambientes y cada uno fue hogar de una de las diferentes poblaciones fuente de las dos variedades taxonomicas, L. s. var. scoparius, o L. s. var. brevialatus. Utilizamos datos de alozimas de cada poblacion fuente para calcular las distancias geneticas entre poblaciones, y una combinacion de datos climaticos y datos de caracteristicas del suelo para calcular las distancias ambientales. En el jardin comun costero mas mesico, la adaptabilidad acumulativa de transplantes (sobrevivencia × produccion de flores) estuvo inversamente relacionada con la distancia genetica entre las poblaciones fuente y residente. En el jardin comun tierra adentro, mas xerico la adaptabilidad acumulativa (sobrevivencia × tamano) disminuyo significativamente tanto con la distancia, tanto genetica como ambiental, despues de excluir una variedad taxonomica del analisis. La distancia geografica estuvo solo debilmente correlacionada con la distancia genetica y tuvo muy poco valor en la prediccion de la adaptabilidad acumulativa de los transplantes. Nuestros datos apoyan la hipotesis de las ventajas de la ubicacion del hogar y el hecho de que la falta de correspondencia de las poblaciones fuente de aquellas semillas geneticamente diferenciadas pueden resultar en un exito reducido de poblaciones restauradas o construidas. Las similitudes geneticas y ambientales de poblaciones fuente deberan ser tomadas en consideracion al seleccionar fuentes de materiales para transplantes.

J. Zhou - One of the best experts on this subject based on the ideXlab platform.

  • responses of soil moisture in different land cover types to rainfall events in a re vegetation catchment area of the loess plateau china
    Catena, 2013
    Co-Authors: S. Wang, Guangyao Gao, Yu Liu, J. Zhou
    Abstract:

    Implementation of the Grain-for-Green project has resulted in significantly increased vegetative cover on the Loess Plateau of China during the past few decades. The plant communities influence soil moisture recharge and usage processes, particularly the input process, which is directly related to transformation of the limited precipitation into available soil water in the semi-arid Loess Plateau. A study to measure soil moisture dynamics of typical land cover types associated with precipitation events was conducted in a re-vegetated catchment area. Smart probes were inserted at 6 different depths below the ground surface under grass (Andropogon), Subshrub (Artemisia scoparia), shrub (Spiraea pubescens), tree (Robinia pseudoacacia), and crop (Zea mays) vegetation to record volumetric soil moisture at 10-minute intervals for a period of 60 days during the growing season in 2011. The advance of the wetting front and total accumulated infiltrated water were measured. The rainfall events were sporadic with widely different intensities, and the soil moisture was replenished mainly by 3-4 heavy precipitation events during July and August. The mean soil moisture content profiles of the 5 vegetation types can be ordered as crop>grass>Subshrub>tree>shrub and this relationship displayed time stability. The different land cover types clearly influenced the water infiltration and water input amounts in the re-vegetated area. The Subshrub site showed the highest total infiltration amount (164 mm) with precipitation (227 mm) during the study period. The grass site had an infiltration amount of 156 mm. The tree site had a total precipitation of 154 mm and an infiltration amount of 97 mm. The infiltration amount was 136 mm for the shrub site and was the lowest (83 mm) for the crop site. Natural grasses displayed a rapid infiltration rate and the wetting front was able to reach a greater depth. (c) 2012 Elsevier B.V. All rights reserved.

  • The hydrological responses of different land cover types in a re-vegetation catchment area of the Loess Plateau, China
    Copernicus Publications, 2012
    Co-Authors: S. Wang, G. Y. Gao, J. Zhou
    Abstract:

    The impact of re-vegetation on soil moisture dynamics was investigated by comparing five land cover types. Soil moisture and temperature variations under grass (<i>Andropogon</i>), Subshrub (<i>Artemisia scoparia</i>), shrub (<i>Spiraea pubescens</i>), tree (<i>Robinia pseudoacacia</i>), and crop (<i>Zea mays</i>) vegetation were monitored in an experiment performed during the growing season of 2011. There were more than 10 soil moisture pulses during the period of data collection, and the surface soil moisture of all of the land cover types showed an increasing trend. Corn cover was associated with consistently higher soil moisture readings than the other surfaces. Grass and Subshrubs showed an intermediate moisture level, with that of grass being slightly higher than that of Subshrub most of the time. Shrubs and trees were characterized by lower soil moisture readings, with the shrub levels consistently being slightly higher than those of the trees. With the exception of the corn land cover type, the average soil temperature showed the same regime as the average moisture content, but exhibiting a downward trend throughout the observation period. Three typical decreasing periods were chosen to compare the differences in water losses. In periods of both relatively lower and higher water soil moisture contents, Subshrubs lost the largest amount of water. The daily water loss associated with corn was most variable. The tree and shrub sites presented an intermediate level, with that of tree being slightly higher compared to shrub; the daily water loss trends of these two land cover types were similar and were more stable than those of the other types. The amount of water loss related to the grass land cover type is determined by the initial moisture content. Soil under Subshrubs acquired and retained soil moisture resources more efficiently than the other cover types, representing an adaptive vegetation type in this area

Houari Benamar - One of the best experts on this subject based on the ideXlab platform.

Houaria Bendjedou - One of the best experts on this subject based on the ideXlab platform.

Maria Paniw - One of the best experts on this subject based on the ideXlab platform.

  • plant behavior and coexistence stem elongation of the carnivorous Subshrub drosophyllum lusitanicum within xerophytic shrub canopies
    Plant Ecology, 2021
    Co-Authors: Stephen J Brewer, Maria Paniw, Fernando Ojeda
    Abstract:

    For many species, facilitation can result in transient species coexistence, but subsequent competition can limit long-term coexistence. Adaptive phenotypic variation in response to increased competition following facilitation, however, could be a means of prolonging coexistence, although this hypothesis remains largely unexplored. Resprouting shrubs following fire in Mediterranean heathlands facilitate seedling establishment and growth of Subshrub species such as the carnivorous plant Drosophyllum lusitanicum. Nevertheless, shrub canopies interfere with prey capture by established D. lusitanicum plants, potentially reducing fitness with increasing time since fire. At three heathland sites in southwestern Spain, we examined the relationship between stem morphology and shrub canopy cover to determine whether D. lusitanicum exhibited vertical or horizontal elongation to avoid shade or interference with prey capture. We also quantified individual performance responses (e.g., survival, growth, flower production) as a function of stem morphology and size of D. lusitanicum plants and shrub canopy cover. Adult plants of D. lusitanicum showed greater vertical elongation with increasing shrub canopy cover. Small adult plants showed an increased likelihood of flowering with increasing shrub canopy cover. The number of flowers produced by flowering plants decreased with vertical elongation when shrub cover was low. We illustrate how coexistence of foundational shrubs and D. lusitanicum could be maintained by a combination of facilitation of D. lusitanicum seedlings and small adults by shrubs and adaptive changes in stem morphology in established individuals to avoid shrub interference, allowing the replenishment of a fire-regulated, persistent seed bank.

  • defining the role of fire in alleviating seed dormancy in a rare mediterranean endemic Subshrub
    Aob Plants, 2017
    Co-Authors: Fernando Ojeda, Maria Paniw, Adam T Cross, Shane R Turner, Kingsley W Dixon, David J Merritt
    Abstract:

    Fire is a topical issue in the management of many ecosystems globally that face a drying climate. Understanding the role of fire in such ecosystems is critical to inform appropriate management practices, particularly in the case of rare and ecologically specialized species. The Mediterranean heathlands are highly fire-prone and occur in a biodiversity hotspot increasingly threatened by human activities, and determining the reproductive thresholds of at-risk heathland species is critical to ensuring the success of future conservation initiatives. This study examined the germination biology of the threatened carnivorous Subshrub Drosophyllum lusitanicum, with specific focus on the role of fire-related cues (heat and smoke) in combination with seasonal temperatures and moisture conditions to determine how these factors regulate seed dormancy and germination. We found that D. lusitanicum produces water-permeable, physiologically dormant seeds with a fully developed, capitate embryo that when fresh (~1 month old) and without treatment germinate to 20-40 % within 4-8 weeks. Seeds possess a restricted thermal window (15-20 °C) for germination and a neutral photoblastic response. Seed dormancy was overcome through precision nicking of the seed coat (>90 % germination) or by short exposure to dry heat (80 or 100 °C) for 5-30 min (60-100 % germination). We propose seedling emergence from the soil seed bank may be cued by the passage of fire, or by soil disturbance from the movement and browsing of animals. Long-term population viability is likely to be contingent upon appropriate management of the persistent soil seed bank, as well as the adequate management of key ecological disturbances such as fire. Drosophyllum lusitanicum faces an increasingly bleak future in the absence of conservation and management initiatives aimed at reducing habitat fragmentation in heathlands and aligning fire management and livestock practices with biodiversity outcomes.

  • Transient facilitation of resprouting shrubs in fire-prone habitats
    Journal of Plant Ecology, 2017
    Co-Authors: Maria Paniw, Roberto Salguero-gómez, Fernando Ojeda
    Abstract:

    Fires play a crucial role mediating species interactions in the Mediterranean Basin, with one prominent example being the nursing effect of post-fire resprouting shrubs on tree recruits, which then outcompete their benefactors throughout succession. Yet, the community structuring role of resprouting shrubs as potential facilitators of post-fire recruiting Subshrub species, which are commonly outcompeted in late post-fire stages, has been overlooked. The aims of this work were to investigate (i) whether proximity to resprouting shrubs increased the demographic performance of a fire-adapted carnivorous Subshrub and (ii) whether mature shrubs negatively affected the performance of established plants through interference with prey capture.

  • Overview of the R code provided in the manuscript
    2017
    Co-Authors: Maria Paniw, Fernando Ojeda, Pedro Quintana-ascencio, Roberto Salguero-gómez
    Abstract:

    Here, we provide an overview of the R scripts and data files to accompany the main text, "Interacting livestock and fire may both threaten and increase viability of a fire-adapted Mediterranean carnivorous Subshrub" and found in this depository. The .R files should be opened with an R editor (e.g., R Studio). The R code is fully commented

  • isolation and characterization of microsatellite loci in the carnivorous Subshrub drosophyllum lusitanicum drosophyllaceae
    Biochemical Systematics and Ecology, 2014
    Co-Authors: Maria Paniw, Manuel Jesus Gillopez, Jose Gabriel Segarramoragues
    Abstract:

    Funding was provided by projects BREATHAL (CGL2011-28759/BOS; Spanish Ministerio de Ciencia e Innovacion-MICINN) and project P07-RNM-02869 (Junta de Andalucia, Spain). M.P. and M.J.G.-L. were supported by an FPI and FPU Ph.D. grants, respectively, from MICINN. J.G.S.-M. was supported by a ‘Ramon y Cajal’ (MICINN-RYC, Spain) postdoctoral contract.

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