摘要:

AbstractInterest in using native grass species for restoration is increasing, yet little is known about the ecology and genetics of native grass populations or the spatial scales over which seed can be transferred and successfully grown. The purpose of this study was to investigate the genetic structure within and among populations ofElymus glaucusin order to make some preliminary recommendations for the transfer and use of this species in revegetation and restoration projects. Twenty populations from California, Oregon, and Washington were analyzed for allozyme genotype at 20 loci, and patterns of variation within and among populations were determined. Allozyme variation at the species level was high, with 80% of the loci polymorphic and an average expected heterozygosity (an index of genetic diversity) of 0.194. All but two of the populations showed some level of polymorphism. A high degree of population differentiation was found, with 54.9% of the variation at allozyme loci partitioned among populations (Fst= 0.549). A lesser degree of genetic differentiation among closely spaced subpopulations within one of the populations was also demonstrated (Fst= 0.124). Self‐pollination and the patchy natural distribution of the species both likely contribute to the low level of gene flow (Nm= 0.205) that was estimated. Zones developed for the transfer of seed of commercial conifer species may be inappropriate for transfer ofE. glaucusgermplasm because conifer species are characterized by high levels of gene flow. Limited gene flow inE. glaucuscan facilitate the divergence of populations over relatively small spatial scales. This genetic differentiation can be due to random genetic drift, localized selective pressures, or both. In order to minimize the chances of planting poorly adapted germplasm, seed ofE. glaucusmay need to be collected in close proximity to the proposed restoration sit

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00101.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractFew early examples of forest restoration projects are extant in the formerly forested parts of eastern North America. In this paper I present the history and status of an early forest restoration project in a denuded gravel pit in Ontario, Canada. The site was part of a deciduous forest until 1840, at which time forest clearing occurred. From 1874 to 1886 the site was exploited as a gravel pit. In 1887, under the direction of William Brown, it was planted with 14 species of coniferous and deciduous trees, of which 10 are still present. No soil preparation was carried out. The trees were pruned for 7 years, but in 1892 intensive maintenance ceased. In the 107 years since planting, the site has acquired some structural characteristics similar to the surrounding native deciduous forest, but it retains characteristics of an artificial community. Canopy cover has increased from 85% to over 95% since 1930 and is primarilyJuglans nigraandAcer platan aides, Survivorship and current growth rates of native and exotic taxa have been similar. Recruitment patterns suggest thatJ. nigraandA. platanoideswill dominate the canopy over the next century. The site is a useful example of the progress and problems created by attempts at forest restoration today.

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00102.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe restoration of the high botanical diversity of the premining jarrah (Eucalyptus marginata) forest is a major priority of rehabilitation following bauxite mining in southwestern Australia. This study investigated the effects of different ripping, seeding, and scarifying dates on the establishment of plants from propagules stored in the topsoil and from applied seed on areas being rehabilitated after mining. Seed stored in the topsoil, rather than applied seed, was the major contributor to plant diversity. Ripping late (April) or scarifying in June significantly reduced the number of species and numbers of individual plants that established from propagules in the topsoil. Species originating from broadcast seed were most numerous when the seed was broadcast in April or after scarifying in June. Scarifying before seeding, particularly in June, increased the establishment of species from the broadcast seed. To make best use of the applied seed, without jeopardizing the establishment of species from the topsoil, pits should be ripped and sown by April. We list a number of strategies that can help maximize plant numbers and botanical diversity on rehabilitated bauxite mines, which may also be of more general application for restoring the original native vegetation on disturbed sites.

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00103.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThis study investigates the influence of gap width and turf type on the growth of planted seedlings of the Australian forbBulbine bulbosa(bulbine lily) and subsequent recruitment of this species from self‐sown seed. In a low‐productivity turf ofDanthonia setacea(bristly wallaby grass), plantedBulbineseedlings established satisfactorily in all gaps 50 mm wide or larger. In highly productive turfs ofFestuca arundinacea(tall fescue) successful, establishment and growth of planted seedlings required a competition‐free gap more than 200 mm wide. Successful recruitment of self‐sownBulbineseedlings was observed in all gap widths inDanthoniaturfs. InFestuca, however, seedling recruitment was low, irrespective of gap width. The results are related to establishing Bulbine bulbosa in habitat reconstruction programs in southeastern Au

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00104.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractWe conducted a study of the flood tolerance of nine wetland tree species on seven soil types. Seedlings were subjected to 11 months of continuous shallow inundation or moist soil conditions on three mineral soils, two organic soils, a manufactured soil designed to mimic the practice of layering muck over mineral soil, and a stockpiled topsoil.Taxodium ascendens, T.distichum, Acer rubrum, andPinus serotinasuffered no mortality;Fraxinus carolininna(1%),Liquidambar styraciflua (8%), P. elliottii(8%), andGordonia lasianthus (24%) suffered low to moderate mortality; andPersea palustris(46%) suffered significant mortality. In general, greatest net height and total biomass were achieved on moist organic soils, and least net height and total biomass were achieved on stockpiled topsoil and inundated soils. Responses to hydrological conditions were less pronounced forTaxodiumspp. If the results of this experiment are transferable to the field, thenAcer rubrum, Fraxinus caroliniana, Pinus serotina, Taxodium ascendens, andTaxodium distichumseedlings can reasonably be expected to survive at least one year under a broad range of hydrological and edaphic conditions. With the exception of Taxodium spp., first‐year growth for the species of this study can be facilitated by maintaining moist but not inundated conditions. These findings suggest that transfer of organic soils will benefit restoration and creation efforts, and that layering organic soil over mineral soil is more effective than using mineral soils or stockpiled topsoi

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00105.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAnnual legumes are often used as nurse plants for restoration projects, but two commonly used legume species were competitors at all densities with Artemisiacalifornica(California sagebrush), a dominant shrub of southern California coastal sage scrub. Survival of Artemisia was not reduced by the lowest densities of the nativeLupinus succulentus(arroyo lupine) at ratios of Artemisia toLupinusof 1:1 or 1:3 or by the exotic Trifolium hirtum (rose clover) at the 1:1 density, but its survival was as low as 4% at the highest densities of Trifolium (1:16) and 1:32). Overall, Trifolium was more detrimental to survival of Artemisia, but the biomass of Artemisia was reduced by 90% or more in mixtures with both legumes even at the lowest densities of 1:1. The total soil nitrogen either did not change or decreased in two of the mixtures between planting and harvest dates, indicating that the legumes not only did not add nitrogen to the soil within one growing season but even depleted it in these two cases. Whereas Lupinus had greater aboveground bio‐mass than Trifolium, it had a lower root density than Trifolium. The Artemisia root system was more shallow than either Trifolium or Lupinus, possibly explaining the poor growth of Artemisia in mixtures, The legumes were one to two orders of magnitude greater in aboveground biomass than Artemisia at the 1:1 ratio and therefore may be inappropriate choices as nurse plants. There is no evidence from this study that either of these legumes can act as nurse plants, even at the lowest ratio of one nurse plant to on shrub. Nurse plants are probably more important in harsher environments than in coastal sage scru

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00106.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractWe monitored several herbaceous species for revegetating motorway slopes in Catalonia, Spain, a Mediterranean country. Two main kinds of treatments were applied: hydroseeding on bare marl, chalk, and slates, and hydroseeding on embankments over gentler slopes, where soil materials previously removed were spread before hydroseeding. The greatest herbaceous cover was obtained by hydroseeding after soil replacement, and marl was the most suitable bare substratum for hydroseeding. Physical characteristics such as schistosily plane in slates and softness or surface irregularity in chalk determined the outcome of revegetation efforts. The most immediate stabilization of soils was obtained on southern exposures with autumnal applications. Grasses, markedly of the generaLoliumandFestuca, were dominant in the herbaceous cover at the end of the monitoring period. Natural invasive vegetation was composed of ruderal species, but no representatives of the adjacent forest or maquis community were found.

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00107.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractExperimental plots of pulverized fuel ash (PFA), alone or mixed with flue gas desulphurization (FGD) gypsum, were seeded with topsoil from areas where PFA had been revegetated naturally, or with estuarine soil. Plots containing fresh PFA became more saline during the first three years due to formation of a salt crust, and these plots experienced colonization by halophytic species. Plots initially containing 2‐year‐old PFA declined in salinity throughout the experiment and were colonized by a richer plant community dominated by legumes. A total of 57 plant species was recorded in the two experiments. Of these,Melilotus officinalis(ribbed melilot),Medicago lupulina (black medick), Vulpia myuros(rat's tail fescue), andPuccinellia maritima(common saltmarsh grass) showed commercial potential for stabilizing these wastes, and by implication other saline or high‐boron mate

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00108.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractOver the last 150 years butterflies have declined rapidly in both distribution and abundance in Britain. The majority of species declines can be linked with widespread habitat destruction that has occurred over the same period. The resulting concern for their conservation has provided many examples of attempts at restoration, most of which have been unsuccessful. The most common reasons for failure appear to be unsuitability of the habitat or lack of knowledge of the species' requirements, but in many cases the recording of the attempt is inadequate for any assessment to be made. Case studies of recent restoration efforts for four butterfly species are used to illustrate that successful restoration depends on detailed study of the species1 ecology and–particularly–habitat requirements, the ability and the resources to manage the habitat to provide those requirements, and a formal scientific approach that maximizes the information gained from the restoration process. As more land in Britain is taken out of intensive agricultural use, opportunities will increase for restoration programs. Prominent and popular species indicative of particular habitats can act as a focus for restoration of the habitat as a wh

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00109.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractDuring the last two decadesChlamydotis undulata(houbara bustard) has declined drastically throughout its range, due primarily to over‐hunting and severe habitat degradation. The threatened extinction of local populations led the National Commission for Wildlife Conservation and Development of Saudi Arabia to implement ex‐ and in‐situ conservation measures: (1) a captive breeding program initiated in 1986, which achieved production of a self‐sustaining breeding flock as well as a surplus for reintroduction by 1992; (2) establishment of a 13,775‐km2 protected area around the last known breeding population in Saudi Arabia; (3) studies of wild birds, to determine densities, feeding ecology, and habitat requirements; and (4) studies on different release techniques (adult releases, sub‐adult releases, feather‐cut sub‐adult releases, and covey releases), carried out since 1991 within the 2,300‐km2fenced and protected area of the Mahaza

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00110.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY