Showing papers on "Native plant published in 1999"

Exotic plant species invade hot spots of native plant diversity

Abstract: Some theories and experimental studies suggest that areas of low plant spe- cies richness may be invaded more easily than areas of high plant species richness. We gathered nested-scale vegetation data on plant species richness, foliar cover, and frequency from 200 1-m 2 subplots (20 1000-m 2 modified-Whittaker plots) in the Colorado Rockies (USA), and 160 1-m 2 subplots (16 1000-m 2 plots) in the Central Grasslands in Colorado, Wyoming, South Dakota, and Minnesota (USA) to test the generality of this paradigm. At the 1-m 2 scale, the paradigm was supported in four prairie types in the Central Grasslands, where exotic species richness declined with increasing plant species richness and cover. At the 1-m 2 scale, five forest and meadow vegetation types in the Colorado Rockies contradicted the paradigm; exotic species richness increased with native-plant species richness and foliar cover. At the 1000-m 2 plot scale (among vegetation types), 83% of the variance in exotic species richness in the Central Grasslands was explained by the total percentage of nitrogen in the soil and the cover of native plant species. In the Colorado Rockies, 69% of the variance in exotic species richness in 1000-m 2 plots was explained by the number of native plant species and the total percentage of soil carbon. At landscape and biome scales, exotic species primarily invaded areas of high species richness in the four Central Grasslands sites and in the five Colorado Rockies vegetation types. For the nine vegetation types in both biomes, exotic species cover was positively correlated with mean foliar cover, mean soil percentage N, and the total number of exotic species. These patterns of invasibility depend on spatial scale, biome and vegetation type, spatial autocorrelation effects, availability of resources, and species-specific responses to grazing and other disturbances. We conclude that: (1) sites high in herbaceous foliar cover and soil fertility, and hot spots of plant diversity (and biodiversity), are invasible in many landscapes; and (2) this pattern may be more closely related to the degree resources are available in native plant communities, independent of species richness. Exotic plant in- vasions in rare habitats and distinctive plant communities pose a significant challenge to land managers and conservation biologists.

Ecological Genetics and the Restoration of Plant Communities: Mix or Match?

Abstract: We present a conceptual framework for choosing native plant material to be used in restoration projects on the basis of ecological genetics. We evaluate both the likelihood of rapid establishment of plants and the probability of long-term persistence of restored or later successional communities. In addition, we consider the possible harmful effects of restoration projects on nearby ecosystems and their native resident populations. Two attributes of the site to be restored play an important role in determining which genetic source will be most appropriate: (1) degree of disturbance and (2) size of the disturbance. Local plants or plants from environments that “match” the habitat to be restored are best suited to restore sites where degree of disturbance has been low. Hybrids or “mixtures” of genotypes from different sources may provide the best strategy for restoring highly disturbed sites to which local plants are not adapted. Cultivars that have been modified by intentional or inadvertent selection have serious drawbacks. Nevertheless, cultivars may be appropriate when the goal is rapid recovery of small sites that are highly disturbed.

Predicting the Landscape‐Scale Distribution of Alien Plants and Their Threat to Plant Diversity

Abstract: Invasive alien organisms pose a major threat to global biodiversity. The Cape Peninsula, South Africa, provides a case study of the threat of alien plants to native plant diversity. We sought to identify where alien plants would invade the landscape and what their threat to plant diversity could be. This information is needed to develop a strategy for managing these invasions at the landscape scale. We used logistic regression models to predict the potential distribution of six important invasive alien plants in relation to several environmental variables. The logistic regression models showed that alien plants could cover over 89% of the Cape Peninsula. Acacia cyclops and Pinus pinaster were predicted to cover the greatest area. These predictions were overlaid on the current distribution of native plant diversity for the Cape Peninsula in order to quantify the threat of alien plants to native plant diversity. We defined the threat to native plant diversity as the number of native plant species (divided into all species, rare and threatened species, and endemic species) whose entire range is covered by the predicted distribution of alien plant species. We used a null model, which assumed a random distribution of invaded sites, to assess whether area invaded is confounded with threat to native plant diversity. The null model showed that most alien species threaten more plant species than might be suggested by the area they are predicted to invade. For instance, the logistic regression model predicted that P. pinaster threatens 350 more native species, 29 more rare and threatened species, and 21 more endemic species than the null model would predict. Comparisons between the null and logistic regression models suggest that species richness and invasibility are positively correlated and that species richness is a poor indicator of invasive resistance in the study site. Our results emphasize the importance of adopting a spatially explicit approach to quantifying threats to biodiversity, and they provide the information needed to prioritize threats from alien species and the sites that need urgent management intervention.

Native and alien species diversity at the local and regional scales in a grazed California grassland

Abstract: Serpentine meadows in Northern California supported higher species richness at the 1-m2 scale than adjacent nonserpentine meadows, and had a considerably higher proportion of native species. Within each soil type, total species richness (natives plus aliens) was unrelated to biomass, cover, soil depth, or soil characteristics (N, P, Ca++, Mg++, water-holding capacity). However, the proportion of native species on serpentine was higher in meadows with lower levels of phosphorus and a lower calcium/magnesium ratio; the proportion of native species in nonserpentine meadows was higher on cool (north to northeast facing) slopes. At a regional scale, some of these effects were partly reversed; the rate at which new species accumulated with the addition of new sites, or beta diversity, was highest for native plant species in nonserpentine meadows. All of the above effects were independent of whether grazing by cattle was absent (removed 13 years ago) or present. The status of low-productivity serpentine soils as a refuge for native grassland species appears to be the result of their abiotic resistance to alien species, but not of a negative relationship between productivity and total species richness.

The role of patch area and habitat diversity in explaining native plant species richness in disturbed suburban forest patches in northern Belgium

Abstract: Relatively easy measurable patch overwhelming importance of patch area relative to habitat variables in determining species richness. This characteristics (especially habitat diversity measures)

Differences in earthworm densities and nitrogen dynamics in soils under exotic and native plant species.

Abstract: Previous studies of the invasion of two exotic plants – Berberis thunbergii and Microstegium vimineum – in hardwood forests of New Jersey have shown a significant increase of pH in soils under the invasive plants as compared with soils from under native shrubs (Vaccinium spp). We present a further investigation of soil properties under the exotic plants in question. We measured the densities of earthworms in the soil under the two exotics and the native shrubs in three parks in New Jersey. In the same populations we also measured the extractable ammonium and nitrate in the top 5 cm of the soil, as well as the respiration of the soils and the potential rates of mineralization (aerobic lab incubation). In addition, we measured the nitrate reductase activity in leaves of the two exotic plants and several native shrubs and trees. Although there were differences between parks, we observed significantly higher earthworm densities in the soil under the exotic species. The worms were all European species. Soil pH, available nitrate and net potential nitrification were significantly higher in soils under the two exotic species. In contrast, total soil C and N and net ammonification were significantly higher under native vegetation. Nitrate reductase activities were much higher in the leaves of exotic plants than in the leaves of native shrubs and trees. Changes in soil properties, especially the change in nitrogen cycling, associated with the invasion of these two plant species may permit the invasion of other weedy or exotic species. Our results also suggest that even if the two exotic species were removed, the restoration of the native flora might be inhibited by the high nitrate concentrations in the soil.

Loss of native aquatic plant species in a community dominated by Eurasian watermilfoil

Abstract: Ecological evaluation of the impact of an exotic species upon native plant species is frequently a combination of historical data prior to introduction and after full establishment with little observation in between. The introduction of Myriophyllum spicatum L. (Eurasian watermilfoil) into Lake George, New York, U.S.A. was first noted in 1985. In 1987, a few newly established plants were allowed to grow unimpeded by human management to document the rate of colonization of this species into a new habitat with its ultimate dominance over, and systematic elimination of, native species. This changing community has been closely monitored over the past decade. Initially a 6 m2 grid system composed of 144 0.5 m2 plots with four radiating transect lines was laid out with the isolated M. spicatum plants as the center. The site was revisited between 1987 and 1997 to mark the extent of the developing M. spicatum bed and its effect on the composition of the native plant community. Since 1987, the area of dense growth has expanded in all directions, impeded only where some physical barrier, such as upper or lower water depth limits or sediment type curtailed its growth. Concurrently, with this expansion, a decline in species richness and abundance of native species was observed.

Observation and Confirmation of Foliar Ozone Symptoms of Native Plant Species of Switzerland and Southern Spain

Abstract: Tropospheric ozone is considered as the major pollutant of concern to the health and productivity of forests in the eastern United States and has more recently become of increasing concern within the forests of southern Europe. Recent observations have clearly demonstrated foliar injury symptoms to be occurring on many tree and native plant species within remote forested areas. Several plant genera (and a few species within genera) found in both the forests of Switzerland and the southern coastal region of Spain exhibit field symptoms typical of ambient ozone exposures. Ozone exposures for many species have been conducted under controlled CSTR conditions and within open-top chambers within the study areas. Results have confirmed that the O3-like foliar symptoms as observed under natural forest and open grown conditions for many native tree, shrub, and herbaceous species in Spain and Switzerland are caused by exposures to ambient O3.

A field study of the effects of elevated CO2 and plant species diversity on ecosystem-level gas exchange in a planted calcareous grassland

Abstract: The relationship between plant species diversity and ecosystem CO2 and water vapour fluxes was investigated for planted calcareous grassland communities composed of 5, 12, or 32 species assembled from the native plant species pool. These diversity manipulations were done in factorial combination with a CO2 enrichment experiment in order to investigate the degree to which ecosystem responses to elevated CO2 are altered by a loss of plant diversity. Ecosystem CO2 and H2O fluxes were measured over several 24-h periods during the 1994 and 1995 growing seasons. Ecosystem CO2 assimilation on a ground area basis decreased with decreasing plant diversity in the first year and this was related to a decline in above-ground plant biomass. In the second year, however, CO2 assimilation was not affected by diversity, and this corresponded to the disappearance of a diversity effect on above-ground biomass. Irrespective of diversity treatment, CO2 assimilation on a ground area basis was linearly related to peak above-ground biomass in both years. Elevated CO2 significantly increased ecosystem CO2 assimilation in both years with no interaction between diversity and CO2 treatment, and no corresponding increase in above-ground biomass. There were no significant effects of diversity on water vapour flux, which was measured only in the second year. There were indications of a small CO2 effect on water vapour flux (3–9% lower at elevated CO2 depending on the light level). Our findings suggest that decreasing plant species diversity may substantially decrease ecosystem CO2 assimilation during the establishment of such planted calcareous grassland communities, but also suggest that this effect may not persist. In addition, we find no evidence that plant species diversity alters the response of ecosystem CO2 assimilation to elevated CO2.

Resource use and foraging patterns of honeybees, Apis mellifera, and native insects on flowers of Eucalyptus costata

Abstract: Introduced honeybees have become well established throughout Australia and concerns have been raised about their impact on the native flora and fauna. Such concerns include the possible depletion of nectar resources by honeybees to the detriment of native animals and the ability of honeybees to pollinate Australian plants. The foraging patterns and resource utilization of honeybees (Apis mellifera) and native insects on flowers of yellow Mallee (Eucalyptus costata) (Behr & F. Muell, ex F. Muell.) were studied in Wyperfeld National Park during spring 1994. Seventy-four insect species visited the flowers with the most prevalent being honeybees, native bees (Lasioglossum and Hylaeus) and ants (Iridiomyrmex). Honeybees began foraging at lower temperatures than native bees and hence had initial access to the nectar supply that was primarily produced overnight by E. costata. However, the majority (90%) of early morning visits to flowers by honeybees involved the collection of pollen. Honeybees did not forage for nectar in substantial numbers until after native insects were active. Despite both consumption and evaporation, nectar supplies remained available at midday and at one site remained available for consumption at dusk. Honeybees regularly made contact with the receptive stigmata while foraging for pollen and hence had pollen loads consisting of numerous E. costata grains present on their body. These activities are indicative of the behaviour required by insects to facilitate pollination. Given the unique morphology of many native flowers and the contrasting findings from studies to date, it is critical that generalisations about the effect of honeybees in the Australian environment are not made from studies on a limited number of native plant species.

Effects of Burning and Grazing on a Coastal California Grassland

Abstract: We tested the effects of fall burning and protection from livestock grazing as management to enhance native grasses on a coastal grassland in central California. Plants from the Mediterranean, introduced beginning in the late 1700s, have invaded and now dominate most of California's grasslands. Coastal grasslands are generally less degraded than those inland and have higher potential for restoration and conservation. Productivity of the experimental plots varied annually and declined over the course of the study because of rainfall patterns. Foliar cover of the native Danthonia californica (California oatgrass) increased more under grazing than grazing exclusion and did not respond to burning. Two other natives, Nassella pulchra (purple needlegrass) and Nassella lepida (foothill needlegrass), responded variably to treatments. The response of N. pulchra differed from that reported on more inland sites in California. Restoring these grasslands is complicated by differing responses of target species to protection from grazing and burning. The current practice of managing to enhance single species of native plants (e.g., N. pulchra) may be detrimental to other equally important native species.

Environmental Weeds and Loss of Native Plant Biodiversity: Some Australian Examples

Abstract: At the species level, weeds have been primarily responsible for the presumed extinction of four Australian plant species and have the potential to force many more native plants to extinction. We discuss two known examples and describe research in progress on several endangered native plant species in relation to the threat posed by the non-native weed Bridal creeper (Asparagus asparagoides). At the ecosystem level, weeds may modify the functioning of natural ecosystems, usually negatively but sometimes positively, depending on the group of organisms being considered. Two Australian weed invasions that have positive, neutral and negative impacts on the invaded ecosystems are discussed. Of the various threats to native plant biodiversity, we conclude that increasing fragmentation of natural vegetation is a major factor that allows weeds to establish and dominate and thereby threaten still further the continued existence of native plant species and the Australian ecosystems in which they occur.

Earthworm responses to plant species' loss and elevated CO2 in calcareous grassland

Abstract: The objectives of this study were: (1) to quantify the effects of plant species' loss from designed calcareous grassland communities at a field site in northwestern Switzerland on the size and composition of earthworm communities, and (2) to evaluate how exposure of plant communities to elevated atmospheric CO2 might alter the effects of plant species' loss on earthworm communities. We non-destructively censused earthworm communities in each of 24 1.2 m2 experimental plots in autumn 1996 when soils were wet and earthworms were active. Each plot contained an experimental plant community with 31, 12 or 5 native plant species (eight plots each). Half of the plots in each species treatment were exposed to ambient CO2 concentrations (350 μL CO2 L-1) and half to elevated CO2 (600 μL CO2 L-1) using screen-aided CO2 control. The study was conducted in the fourth year after community establishment and the third year of CO2 treatment as part of a long-term study on the interactive effects of plant species' loss and elevated CO2 on grassland communities. The size (density and biomass) of earthworm communities declined linearly when the number of plant species in the community was reduced from 31 to 5 species (e.g. 32 ± 1 g m-2 to 23 ± 2 g m-2) due mainly to a decline in the endogeic worm species Allolobophora rosea which was the most abundant of nine earthworm species observed (nearly half of all worms in each plot). However, no changes in the relative contribution of individual species or the three main earthworm ecological groups (anecics, endogeics, epigeics) to the entire earthworm community were observed with declining number of plant species. The responses of earthworm communities to plant species'; loss appear to reflect changes in community fine root biomass in the topsoil (e.g. declining worm biomass with declining fine root biomass) observed in parallel studies conducted at this site. Further the results of this study demonstrate that a loss of plant species from these calcareous grassland communities may also alter the age structure of earthworm communities, but not significantly influence their diversity or composition. Our data also indicate that rising atmospheric CO2 may not greatly impact the size and composition of worm communities or alter the effects of plant species' loss on earthworm communities. Therefore, the disappearance of plant species from these native grasslands, as a result of ever increasing human activities, may be expected to lead to reductions in the size of earthworm communities and the ecosystem services they provide.

Land use change effects on breeding bird community composition.

Abstract: We identified land uses, vegetation cover types, and landscape patterns associated with avian community diversity in 2 rural landscapes in a hardwood forest-tallgrass prairie ecotone that differ with regard to human population density. We obtained long-term (24 years) changes in avian community composition through records from the North American Breeding Bird Survey. We obtained historical and present land use, vegetation cover types, and landscape structure of both landscapes from high-resolution aerial photography. Avian community composition in the low density rural population landscape was primarily related to the amount of land in deciduous forest and land treated with fire or herbicides. In contrast, avian community composition in the high density rural population landscape was primarily related to the amount of land in deciduous forest, native grassland, and roads. Changes in vegetation cover type were related to changes in the avian community composition by increasing prairie habitat associated species in the low density rural population and generalist habitat associated species in the high density rural population landscapes. Loss of neotropical migrants and increased number of generalist species in the high density rural population landscape was related to decreased native vegetation, road development, and increased landscape fragmentation. Biologists and conservationists in this region should focus attention on preserving biological diversity of rural ecosystems by maintaining native plant communities.

Establishing tallgrass prairie on grazed permanent pasture in the upper midwest

Abstract: The goal of the study was to learn whether native prairie grasses and, eventually, a diverse mixture of native forbs could be incorporated in permanent pastures by means of rotational grazing by cattle. An experiment was established on a farm in northeastern Iowa on a pasture that had never been plowed but had been grazed since the 1880s. One treatment was protected from grazing to test for the presence of remnant vegetation. Andropogon gerardii , Sorghastrum nutans , Panicum virgatum , and Desmanthus illinoensis were introduced in plots first treated with glyphosate; seeds were either drilled (DR) or hand-broadcast and incorporated by controlled cattle trampling (BT). Seedling establishment and aboveground biomass were followed over 3 years. There was no evidence for remnant native plants on uplands, but seven species of native forbs and four native graminoids flowered in exclosures erected within waterways. D. illinoensis initially established up to 12 seedlings/m 2 but had disappeared from all but one plot by the third year. Variation in native grass establishment among replicate plots within treatments was very high, ranging initially from 0.2 to 9.9 plants/m 2 . In August of the second year, native grasses made up only 8% of the available forage in DR plots and 1% of BT plots. One year later, however, native grasses made up 56% of the available forage in DR plots and 37% of BT plots, and these differences were significant ( p 5 0.05). A pilot study seeded in late winter (frost seeding) suggested that seeds spread after cattle trampling produced five times more seedlings (2.5/m 2 ) than seeds spread before cattle trampling (0.5/m 2 ). Frost seeding had advantages because

Selecting plant species for ecological restoration: A perspective for land managers

Abstract: We recommend in this paper that land managers adopt a policy of mandatory use of native plant species for revegetation and restoration of severe disturbances on wildlands throughout the Interior West. A review of the relative advantages and disadvantages of using introduced and native species suggests that selection criteria based on ecological adaptability and suitability are more consistent with the objectives of ecosystem management than are criteria based on cost, availability, familiarity, or other nonecological considerations. We suggest that land managers initiate a policy requiring the collection and accumulation of native seral species throughout their respective regions and districts to be used in restoration activities. Further, we suggest that such a policy will foster closer ties between public land managers and public research scientists, and will enhance the implementation of science-based land management.

Propagation and establishment of aquatic plants : a handbook for ecosystem restoration projects

Abstract: : Unlike natural lakes, reservoirs generally do not have well-developed aquatic plant communities. As man-made ecological systems, reservoirs are relatively young and often lack aquatic plant propagules of appropriate native plant species. These man-made systems are also operated to achieve specific project objectives such as flood control, navigation, etc. As a result of these reservoir operations, water levels often fluctuate dramatically, making natural establishment of aquatic plants from seeds difficult or impossible. Reservoirs are also frequently populated by large numbers of opportunistic omnivores such as common carp. Grazing by these omnivores and aquatic herbivores may be too intense to allow natural establishment, particularly in light of the low numbers of propagules and relatively harsh environmental conditions offered by many reservoirs. In order to establish a diverse native plant community, robust propagules of desirable aquatic plant species must be introduced into selected, favorable environments and be provided with protection from grazing during early establishment. This handbook provides general information on production of aquatic plant propagules and methods of planting that should facilitate the development of diverse native plant communities. An appendix provides specific information on propagation and planting of selected native aquatic plant species.

Nutrient cycling and growth in forest ecosystems of south western Australia: Relevance to agricultural landscapes

Abstract: Nutrient and hydrologic cycles in harvested native forests in southern Australia are largely balanced. For example, we have little or no evidence of any decline in nutrient capital or availability in harvested forests. Short-term and small-scale reductions in evapotranspiration due to loss of leaf area after harvesting are adequately balanced at the landscape scale by large areas of regenerating or older-age forest. In contrast, agricultural systems on similar soils are a) dependent on large inputs of fertilisers to maintain growth and b) frequently subject to increasing salinity and waterlogging or other forms of degradation. The large-scale replacement of long-lived communities of perennial and often deep- rooting native species with annual crops or other communities of shallow-rooting species might be better managed within the framework of knowledge developed from studies of native plant communities. However, application of such a mimic concept to systems of low natural productivity is limited when agricultural systems require continued high productivity. Nonetheless, the mimic concept may help in developing sustainable management of agriculture on marginal lands, and contribute to the nutritional resilience of agroecosystems. Relevant characteristics for mimic agroecosystems in south western Australia include: high species diversity, diversity of rooting attributes, utilisation of different forms of nutrients (especially of N and P) in space and time, and the promotion of practices which increase soil organic matter content.

Lessons from historical rangeland revegetation for today's restoration

Abstract: Rangeland revegetation in the Western United States historically was applied at a large scale for soil conservation and forage production purposes. Principles of revegetation that have developed over years of research include matching site potential and plant materials adaption, use of appropriate seedbed preparation and sowing techniques, and development of large supplies of seed of adapted plants. Although many of these large-scale projects were extremely successful in terms of their original objectives, they often lacked native plant diversity. Increased use of native species for revegetation of these lands, in the face of exotic weed spread, will require a more detailed knowledge of disturbance effects relative to site potential and of native plant requirements for establishment and persistence in mixed communities.

Investigation of the relationships between biomass reduction, soil disturbance, soil nutrients and weed invasion in basalt plains native grassland remnants in Victoria, Australia

Abstract: The investigations reported in this thesis examined the relationships between biomass reduction (burning and mowing), soil disturbance, soil nutrient levels (N, P and K) and weed invasion in native grassland remnants in Victoria, Australia. The study was carried out at three native grassland remnant sites, Derrimut grassland reserve, Laverton grassland reserve and Victoria University of Technology, St. Albans campus grassland reserve on the westem edge of Melboume, Australia. These grassland remnants belong to the Western Basalt Plains grassland community which is listed as threatened in Victoria, and which forms part of the lowland temperate grasslands which once extended across south eastern Australia. A major threat to the survival of these communities is invasion by a variety of weeds. Weed invasion is often markedly enhanced by disturbance of the soil due to ploughing and overgrazing. It is known that some type of biomass reduction (burning, mowing or grazing) is required to prevent the dominant native perennial tussock grasses from over shadowing the diversity of forbs that grow between the tussocks, but the effects of various biomass reduction methods on weediness, and the underlying causes of weediness, have not been studied in any depth. The outcomes of the investigation are currently being applied to the management and rehabilitation of lowland grassland remnants. Most previous studies of lowland grassland rehabilitation and management have assumed that the key determinant of competition between native and exotic plant species in lowland grasslands is above-ground cover. The results reported in this thesis clearly show that below-ground competition for nutrients is also important in determining the extent of exotic and native plant growth in intact and disturbed areas. The successful establishment of native species during revegetation, with low levels of weed growth, will depend on the extent to which below ground growth of natives is achieved to lower available nutrient levels quickly, and prevent large scale growth of exotics. The management of lowland grassland remnants with low levels of flatweeds and annual grasses will likewise depend on the maintenance of a healthy sward of native vegetation which can keep available nutrients in the soil at low levels, especially when above-ground cover is removed by biomass reduction actions such as burning, mowing and grazing.

Native plant restoration on the Going-to-the-Sun Road, Glacier National Park

Abstract: Since 1991, 53 acres of roadside vegetation and soil were removed along sections of the historic Going-to-the-Sun Road during road rehabilitation activities. Restoration strategies used indigenous plant material to re-establish plant cover, prevent erosion, compete with exotics, and improve aesthetics. From several hundred collections, simple seed mixes were created that included early colonizers and late seral species. Native forbs, shrubs, and trees were propagated as bareroot and containerized material. Grass was grown as seed and increased to larger quantities with offsite seed production plantings. Revegetation incorporated a combination of plant and soil salvage, seeding, inplanting, and natural regeneration. Our monitoring program was used to assess results and to help make decisions about species selection, seeding rates, successional strategies, and realistic objectives for restoration.

Management of small mammals in a relict grassland in california's central valley

Abstract: Populations of many small mammals in the western United States have declined as a consequence of changes in land-use patterns over the past century. ln California's Central Valley these changes have resulted in replacement of native grassland vegetation by non-native annual grasses. Jepson Prairie is a natural reserve that has been set aside to preserve native vernal pool and bunchgrass habitats. Jepson Prairie also provides habitat for several state and federally listed threatened or endangered species, including plants insects, and vertebrates. Current management of the reserve includes prescribed burning and grazing by domestic sheep to foster restoration of native grasses. We examined the effects of prescribed burning on small mammals by censusing small mammal communities inhabiting burned and unburned habitats over a one-year period. Nine censuses (6720 trap-nights) resulted in a total of 2 15 captures of five species. Three of these species (deer mouse, Pemmyscw maniculatus, California vole, Microtus californicus, and Botta's gopher, Thomomys bottae) are common in many parts of California. The remaining two are either reduced in numbers (California kangaroo rat, Dipodomys californicus) or listed as Federal Special Concern (FSC) species by the state of California (San Joaquin pocket mouse, Pemgnathus inornatus inornatus); it is worth noting that only one capture was made of the latter species. In general, extremely low and varying capture rates suggest that Jepson Prairie may be poorly suited to supporting populations of small mammals, although habitat management could substantially improve conditions for these species. For sites such as Jepson Prairie to be managed to maintain small mammal populations, we recommend 1) acquisition of upland habitat to provide refuge from seasonal flooding; 2) control of domestic and feral cats; and 3) a comprehensive prescribed burning program to restore native plant species, reducing the need for grazing.

Collection and production of indigenous plant material for national park restoration

Abstract: The National Park Service is taking the "Restoration" approach to reestablishing native plant communities by salvaging topsoil and by seeding and planting native indigenous plant mate- rials. In this way, they are making every effort to protect the genetic integrity of the often unique native plant resource. Since 1985, Yellowstone and Glacier National Parks have been working with the USDA Natural Resources Conservation Service, Plant Materi- als Center in Bridger, MT, to identify native plant species from which seed can be readily collected, propagated on a large scale, and successfully reestablished on disturbed roadsides. Early colonizers are utilized for initial protection and stabilization, but late seral dominant species are added to mixtures to add longevity to result- ing plant communities. Revegetation, reclamation, and restoration all imply the reestablishment of plant cover on a disturbed site, but if taken literally may imply three levels or intensities of site mitigation. "Revegetation" is simply the reestablishment of plant cover, often a monoculture of an introduced plant species. Although relatively inexpensive, revegetation may not offer permanence or ecological stability. "Reclamation" has been defined historically as the process of returning disturbed land to a condition that approximates the original site conditions and is habitable by the same or similar plants and animals that existed on the site before disturbance (Redente and others 1994). Restoration strives to emulate the structure, function, diversity, and dynamics of a specific ecosystem. Topsoil salvage can preserve the soil biota along with viable propagules in indigenous plant materials. By utilizing native indigenous materials (seed, cuttings, trans- plants), the genetic integrity and diversity of the native plant communities may be maintained. Even with soil sal- vage and the use of native indigenous plants, restoration must not be interpreted as a discrete event, but rather as an ongoing process involving the reestablishment of nutrient cycling, plant succession, and plant community dynamics. The U.S. Department of the Interior, National Park Ser- vice has adopted a policy of restoration of all disturbed sites related to road construction, visitor impact, and facility maintenance. The National Park Service is committed to maintaining the genetic integrity of the unique native flora, with secondary goals of erosion control, competition with exotic and noxious invasive plants, and improving overall

Impact of Aquatic Plant Management Methodologies on Eurasian Watermilfoil Populations in Southeast Wisconsin

Abstract: Declines and increases in Eurasian watermilfoil populations (Myriophyllum spicatum L.) throughout North American Lakes have highlighted the need for long-term studies. Similarly, understanding the long-term implications of different aquatic plant management techniques (e.g., mechanical harvesting, chemical treatment, no management) is a crucial component of aquatic plant management. We examined the aquatic plant communities and management techniques for nine Southeast Wisconsin lakes for a period of 6 to 9 years prior to 1996 to assess the long-term population changes of Eurasian watermilfoil subjected to different management regimes. In eight of the nine lakes, the Eurasian watermilfoil populations either declined in frequency or remained constant; while in seven of the nine lakes the native aquatic plant community either increased in average number of plant species per sample location or remained constant The long-term aquatic plant community information for these nine case study lakes suggest ...