BioOne.org will be down briefly for maintenance on 14 May 2025 between 18:00-22:00 Pacific Time US. We apologize for any inconvenience.
Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact helpdesk@bioone.org with any questions.
Over the last 150 years, agriculturally-productive landscapes of the Midwestern United States have been heavily transformed by human land use; presently, little native vegetation remains and few protected areas exist. Natural areas that have persisted through this extended period of landscape change, however, may comprise important reservoirs of biodiversity and may contain biotic and structural legacies important for understanding and restoring native ecosystems. Here we integrate several data sources (including original Public Land Survey records, state atlases, aerial photography, and forest inventory data) to identify and characterize potential remnant woodlands within the 27,520 ha Clear Creek watershed in eastern Iowa. Analysis across data sources reveals that these woodlands have likely changed substantially in extent, configuration, and composition since pre-Euro-American settlement. While the combination of early data sources reveals substantial deforestation within the watershed, the processes of reforestation and afforestation characterize landscape change since 1940. Potentially remnant woodlands today comprise only 0.3%–2.6% of the watershed, and are concentrated in or near riparian zones. Compositional shifts are indicative of changes in the key processes regenerating contemporary woodlands in comparison to their historical counterparts; oak species (Quercus alba L., Q. rubra L., Q. macrocarpa Michx.) were historically dominant whereas Acer saccharinum L., Salix nigra Marsh., Ulmus americana L., and A. negundo L. are dominant today. Our delineation revealed numerous candidate remnant woodland patches, and informs future field research and ongoing conservation efforts in the watershed.
Fire suppression and altered water drainage often change community structure and species composition in human-dominated ecosystems. We describe the decline of sawgrass marshes between 1940 and 2002, and assess the current condition of remnant marshes within the MacKay Tract, an isolated wetland embedded within rapidly developing eastern Orlando, Florida. We tested the correlation between live sawgrass and presence of adult hardwood trees and seedlings (primarily red maple, Acer rubrum) and describe vegetation in plots with different levels of tree encroachment. Total area occupied by open sawgrass in the MacKay Tract has declined dramatically the last 60 years; in 2006, open sawgrass comprised only 12% of the area covered in 1940. Tree basal cover was negatively associated with live sawgrass and positively related to red maple seedling density, but not associated with dead sawgrass tussocks. Sawgrass was positively correlated with the second axis of a non-metric multidimensional scaling ordination on understory plant assemblage, while red maple seedlings and several species associated with disturbed areas were significantly negatively correlated with this axis. Another nine plant species were positively correlated with the first axis, while Osmunda cinnamomea (cinnamon fern) was negatively associated with it. We suggest that woody species are continuing to colonize what is left of the sawgrass marsh. Without intervention (e.g., restoring hydrologic flow and fire), the sawgrass (Cladium jamaicense Crantz) area within the marsh will continue being replaced by woody and exotic species.
KEYWORDS: community structure, habitat heterogeneity, habitat use, mammal species diversity, Neotoma mexicana, Peromyscus gratus, population dynamics, population extinctions
We studied the influence of habitat loss and fragmentation in species diversity, population dynamics, and habitat use in a small mammal community in xeric palo loco (Senecio praecox) thickets at Reserva Ecologica del Pedregal de San Angel, a completely isolated nature reserve in Mexico City, Distrito Federal, from 1989 through 1990. It is a heterogeneous region, dominated by an old lava flow, with many boulders and crevices. Small mammals were captured using Sherman live traps in two 0.81-ha grids; each grid contained 10 rows and 10 columns, separated by 10 m. Nine species have disappeared since 1957 as a result of the loss of particular habitat such as grasslands, habitat fragmentation, and other causes. In our study, we recorded nine species; five species were exclusively recorded in the continuous native scrub of the reserve. Therefore, they are good indicators of the sites in the reserve that maintain the less perturbed habitats. Interestingly, no introduced rodents (i.e., roof rat (Rattus rattus) and house mouse (Mus musculus)) were found in the continuous scrub of the reserve. Only six were caught in our grids (three were relatively common, represented by more than 10 individuals). Reproduction and maximum population densities of all species were very seasonal and peak at time of available high food resources, suggesting that food availability was the limiting factor.
The National Parks System of Argentina (NPSA) comprises 33 protected areas (3,546,044 ha) and represents 1.25% of the country's total area. The goal of this work is to provide the first description of the distribution of invasive mammal species within the NPSA based on various information sources in order to assist future decision making concerning management strategies for these species. The occurrence of invasive mammals in different areas of the NPSA was determined from diverse sources: internal reports, mammal collections, survey questionnaires, and literature review. Sixteen invasive species are established within 26 of the 33 (78.7%) protected areas of NPSA. The most widespread species is European hare (Lepus europaeus Linnaeus), followed by wild boar (Sus scrofa Linnaeus). Highest relative invasion indices are recorded in areas within the Patagonian forest, followed by areas in the Patagonian steppe. Two clearly different situations are present in the protected areas of the NPSA: (1) areas situated within the southern ecoregions, where invasive species have mostly been introduced for big game hunting purposes or fur farming, and (2) areas situated within the northern ecoregions, where the dominant invaders are feral species linked to cattle farming activities.
We compared the extent to which exotic species are associated with horse trails, old roads, and intact communities within three native vegetation types in Ozark National Scenic Riverways, Missouri. We used a general linear model procedure and a Bonferroni multiple comparison test to compare exotic species richness, exotic to native species ratios, and exotic species percent cover across three usage types (horse trails, old roads, and intact communities) and three community types (river bottoms, upland waterways, and glades). We found that both exotic species richness and the ratio of exotic species to native species were greater in plots located along horse trails than in plots located either in intact native communities or along old roads. Native community types did not differ in the number of exotic species present, but river bottoms had a significantly higher exotic to native species ratio than glades. Continued introduction of exotic plant propagules may explain why horse trails contain more exotic species than other areas in a highly disturbed landscape.
Japanese barberry (Berberis thunbergii DC.) has rarely been observed to experience noticeable defoliation from insect or mammal herbivores, and this freedom from enemies is presumed to contribute to its invasiveness. However, during the summer of 2007, I observed extensive defoliation of current year's shoots on Berberis populations across central and northern New Jersey. Additional reports from volunteer observers showed that similar amounts of herbivory occurred in southern New York. I examined the upper 15 cm on a sample of 4868 current year's shoots on 320 plants in a population in New Jersey; of these shoots, 11.6% were completely defoliated, 65.3% were partially defoliated, and 23.1% showed no defoliation. Only 9% of plants showed no defoliation on any shoot; 87% of these were small plants with less than three stems per root base. The fraction of stems completely or partially defoliated was higher on larger plants (more stems per root base), but did not vary with slope position, plant density, or numbers of current year's shoots per plant. The defoliating agent was shown to be Coryphista meadii, the barberry geometer, a lepidopteran native to all of North America. Further studies will be necessary to determine if the herbivory is recurrent, if it is occurring throughout the introduced range of B. thunbergii, and if it has impacts on barberry's reproduction, growth, and survivorship.
Prescribed burning has been used by the North Carolina Division of Parks and Recreation (DPR) since 1974 to reduce hazardous fuel loads, to restore/maintain specific habitats, and to preserve rare species populations within state parks, recreation areas, and natural areas. System-wide staff training, development of burn prescriptions, and burning procedures were mandated according to agency guidelines. During 2002–2007, prescribed burns within state park properties were conducted mostly in the coastal plain, but system-wide coverage was far less than adequate to maintain fire-dependent communities. The number of hectares treated per year as a percentage of the number needing treatment decreased yearly. In addition to weather conditions, common obstacles to achieving burning goals included conflicts with other responsibilities, lack of trained staff/dedicated funding, and increasing wildland-urban interfaces. Prescribed burning data and associated information from state parks and natural areas in Virginia, South Carolina, Georgia, and Florida indicated that interagency burning agreements, full-time burning staff, and use of contractors have improved burning results significantly in recent years. Prescribed fire councils have served as advocates for prescribed burning at state-wide levels, while prescribed burning legislation has helped to limit smoke and, in some states, fire damage liability. Suggested enhancements for the DPR prescribed burn program include: use of both internal and external burning organizations, development of cooperative agreements with analogous programs, pursuit of earmarked state funds and outside grants, expansion of staff burn training, active participation in prescribed fire advocacy groups, and site-specific public information/education to address local concerns and to promote benefits of prescribed burning.
One of the most comprehensive attempts at biodiversity conservation in Russia and the former Soviet Union has been the establishment of an extensive network of protected natural areas. Among all types of protected areas in Russia, zapovedniks (strictly protected scientific preserves) have been the most effective in protecting biodiversity at the ecosystem scale. Russia has 101 zapovedniks with a total area of 34.3 million ha, representing 2% of Russian territory. The mission of zapovedniks is to protect native biodiversity and ecosystem processes as well as to facilitate the study of natural ecosystem processes and functions. In this manuscript, we provide a brief history of Russian ecosystem preservation and outline the goals and administrative organization of the Russian zapovednik system as it currently functions, as well as the characteristics, problems, and values of the system.
All jurisdictions face a problem of effectively allocating scarce resources to conservation efforts. Key steps in improving allocation of conservation resources are establishing specific goals to guide conservation efforts, ensuring that those goals address the challenges of jurisdictional rarity, and creating tools that can assign species quickly to appropriate actions and rank species or ecosystems for conservation effort. We describe goals for conservation that assist resource allocation within jurisdictions and two tools to help the process. One tool sorts species into practical groups for conservation action. It creates groups of species requiring similar actions. The other tool assigns conservation priorities. It orders species or ecosystems based on criteria governing risk, modified by feasibility, stewardship responsibility, disjunctiveness, and pattern of range collapse. Priorities can be ordered within an action group, within a goal, or as an overall rank. Results of applying the approach are illustrated using examples from British Columbia.
Mangrove forests provide an important ecosystem service of safeguarding human societies from natural disasters along tropical coastal zones. With recent major coastal disasters, including the South Asian tsunami in 2004 and the observed protection buffer that mangroves have provided, valuating mangrove ecosystems for protecting coastal areas from natural disasters is a necessity for appropriate conservation planning of ecosystem services. In this article, I assess the avoidance and replacement costs of mangrove ecosystems in South Asia, in reference to the South Asian tsunami of 2004. The findings demonstrate that the coastal protection value of mangroves exceeds direct-use values of mangroves, such as forest harvesting and mariculture, by over 97%. Mangrove ecosystems are highly valuable for protection against natural coastal disasters, and their conservation and restoration are needed to maintain national and global natural capital.
This article is only available to subscribers. It is not available for individual sale.
Access to the requested content is limited to institutions that have
purchased or subscribe to this BioOne eBook Collection. You are receiving
this notice because your organization may not have this eBook access.*
*Shibboleth/Open Athens users-please
sign in
to access your institution's subscriptions.
Additional information about institution subscriptions can be foundhere