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Oak reproduction is often scarce or lacking in oak savannas under ecological restoration management, despite the fact that large canopy gaps created by the removal of invasive brush allow abundant sunlight to reach the ground surface. I conducted two experiments to investigate the effect of manipulating surface vegetation on the acorn-caching behavior of squirrels (gray squirrel Sciurus carolinensis; fox squirrel S. niger; or southern flying squirrel Glaucomys volans) and blue jays (Cyanocitta cristata). In Experiment 1, I created 10 × 10 m bare-ground patches prior to the time of acorn dispersal in restored white oak (Quercus alba) savanna and in adjacent unrestored brushy oak woods. I then compared oak seedling establishment in these bare patches the following summer to seedling establishment in unaltered tall vegetation. In Experiment 2, I used a combination of late-summer burning, tilling with an agricultural disc, and applying herbicide to create bare-ground patches adjacent to established oak woods, and then compared oak seedling establishment in these areas the following summer to that in burn-only, mow-only, and unaltered vegetation. In both experiments, oak seedling establishment was greater in areas denuded of ground vegetation. This agrees with previous research, which concluded that blue jays have a preference for storing acorns in areas of low to bare surface vegetation.
This paper analyzes the spatial distribution of environmental infractions (EIs) in the “Núcleo Caraguatatuba” (NuCar) division of the Serra do Mar State Park (PESM in Portuguese) in Brazil. This region, NuCar, of the PESM is a protected area with potential for economic and tourism development. Between 2000 and 2016, 117 environmental infractions were registered according to three sources of data: (1) Brazilian Institute of Geography and Statistics, (2) Forestry Foundation database, and (3) DataGeo, a Spatial Data Infrastructure (SDI) combining environmental and socioeconomic database spatial/environmental data for the state of São Paulo. The three most common violations were deforestation, irregular occupation, and heart of palm extraction. Geospatial analysis of the data focused on the main roads and trails and different zones defined by the Park Management Plan corresponded to these areas of increased access. As well as suggestions for increased control and surveillance of cluster areas to restrict opportunities for EIs, this paper also discusses other aspects of management that influence the number of violations in protected areas. These include open, respectful communication between residents and park management to reduce conflict and enacting the socio-environmental park program and the PESM management.
The oases of the Baja California peninsula have served as biological refugia for unique and relict biological groups since the late Pleistocene. In this paper, we identified and analyzed the floristics associations in aquatic and riparian vegetation. We also investigated impacts of human activity and geographic factors on the oasis vegetation. A total of 248 species, including relic (e.g., Thelypteris puberula, Epipactis gigantea) and 56 nonnative species, were identified. Some exotic plants such as Cryptostegia grandiflora, Arundo donax, and Pennisetum ciliare were invasive. Species richness of the oasis plants exhibited a stronger correlation with oasis size (or area) but less with latitude, longitude, and elevation. Human activities, including introductions of exotic species, appeared as a threat to the oasis vegetation. Presence of the rare and relict species warrants a high-priority protection of these unique and vanishing mesic ecosystems from human threats.
Restoration is a critical component of grassland conservation worldwide, but grassland management requires disturbances that maintain the habitat. Further, successful restorations need to support not just a vegetative community, but also a diverse community of other organisms that contribute to a range of ecosystem functions. Large herbivore grazers like American bison (Bison bison) can be an important part of these management strategies, but their role in functions like nutrient cycling relies in part on dung beetles (Scarabaeidae: Scarabaeinae and Aphodiinae, and Geotrupidae), which provide valuable ecosystem services by removing and burying dung. We evaluated dung beetle community responses and dung decomposition in restored and remnant prairies shortly (1.5 y) after bison reintroduction. Dung beetle abundance was significantly greater where bison were present, where prescribed fire had been applied in the past year, and in older restorations and remnants. These same environmental characteristics also shifted the composition of beetle communities, but not total community biomass, as the increased abundance was driven by small-bodied species. Dung decomposition varied with bison presence and site age, with the highest rates of decomposition in an old restoration with bison present. These results indicate that dung beetle communities are capable of rapidly responding to bison introduction, a promising sign that land managers may be able reestablish ecosystem-level processes driven by large grazers in restored grasslands.
Carbon (C) storage and accumulation in forests is of growing importance as climate change focuses our attention on rising greenhouse gas emissions. In 2012, we measured total ecosystem C pools (including live vegetation, dead wood, and soils) in two unmanaged, mixed-species stands in central Maine, USA. The stands are adjacent to one another and serve as references against which silvicultural treatments can be compared. The soil parent material of the stands was different (marine sediments versus glacial till), which provided an ideal opportunity to compare C stocks between these stands. We used tree ring analysis and repeated forest inventories to estimate tree and dead wood recruitment patterns and past disturbance severity. Site quality influenced C trajectories through its influence on tree species composition, which in turn strongly determined stand susceptibility to insect outbreaks. In 2012, total ecosystem C stocks were 196.3 ± 9.6 Mg ha–1 (mean ± SD) in the stand on soils derived from marine sediments and 247.0 ± 17.7 Mg ha–1 in the stand on soils derived from glacial till. Differences in average total ecosystem C stocks were primarily driven by the live tree C pool. Despite the occurrence of several partial disturbance events from 1954 to 2012, live tree C stocks increased over time in both stands. Average C accumulation in recruited dead wood was also positive, indicating that aboveground biomass served as a C sink. Our results can be used to inform decisions related to C objectives in unmanaged stands of similar species composition and soils.
In the absence of a disturbance regime, flora at historical oak sand barrens change as leaf litter builds up and increasing canopy cover shades bare soils. Over time, black oak sand barrens become more mesic, and other trees including Acer rubrum, Fraxinus sp., Prunus serotina, and Sassafras albidum often mix with oaks in the canopy. Three different restoration techniques were applied to recreate disturbance across 10 sites within degraded black oak (Quercus velutina) glacial kames, which are mounds of sand and gravel deposited by melting ice sheets: select canopy tree thinning favoring 5–30% tree canopy cover, forest floor leaf litter removal, and prescribed fire. Ground layer richness and abundance 1 and 3 y after treatment were assessed within modified North Carolina Vegetation Survey plots and compared against both temporally and spatially equivalent control sites. Thinning the canopy induced the greatest vegetation response in species diversity, whether as xeric-tolerant indicator species, graminoid species, as a taxonomic group, or pooling all plants. Leaf litter removal produced a modest pulse response from a few select species released from the shade-creating effects of accumulating leaf litter. Prescribed burns did not create a disturbance sufficient for any significant plant response, presumably because low-intensity burning minimally reduced leaf litter cover. Thus, manipulations that opened the canopy and reduced soil moisture more directly induced barren-species recovery than did efforts to recreate historical disturbance processes.
Natural areas are tracts of land with little or no evidence of past human influence and designated for research, education, and conservation. Many sites were selected to represent high-quality examples of both common and rare plant association groups. However, the extent to which natural areas characterize regional environmental conditions or gradients important for measuring and understanding the effects of climate change has not been examined. We compared the current collection of natural areas in Oregon and Washington to the broader natural ecosystems found in the region using four ecological parameters derived from existing datasets: forest structure, dominant tree species, vegetation formation classes, and elevation. We evaluated these data sets at both the regional and ecosystem scales and looked at the influence of land ownership in representing these parameters. Our results suggest that the Pacific Northwest natural areas network is well representative of all four parameters at the regional level. There were some gaps in representation at the ecoregion scale and across some land ownerships. Results from this study further support using natural areas for monitoring long-term climate change effects in the Pacific Northwest.
Collaborative efforts between indigenous peoples and government land managers are gaining recognition as important elements of forest restoration. Unique land allocations, such as the Research Natural Area (RNA) system of the US Forest Service, necessitate novel approaches to achieve desired outcomes among stakeholders. We describe a Traditional Ecological Knowledge (TEK) framework that integrates efforts among resource managers, tribal representatives, scientists, and a tribal youth intern program to conduct ecological restoration in a Jeffrey pine (Pinus jeffreyi) forest ecosystem of the western United States with a history of frequent fires. Reintroduction of TEK-based practices provided some moderation of fire effects during an unplanned wildfire event, benefiting both ecological conditions and a traditional Paiute Indian food source, piagi, the larvae of the Pandora moth (Coloradia pandora). Tribal youth learned about traditional food collection and land management practices, and federal managers discovered that TEK helped achieve ecological restoration goals. Our collaborative framework increased confidence in the mutual benefits of western science- and TEK-based forest management practices, creating a foundation for long-term partnership in ecosystem restoration.
Wildfires and events that follow such as flooding and erosion are natural disturbances in many ecosystems. However, when these types of postfire events threaten life, property, and resources they become a concern for resource managers, communities, and private landowners. A procedure for rapid assessment that uses different tools exists for federally owned lands, however after wildfire many non-federal landowners wonder how to manage and reduce risk on their lands. For this reason it is important to understand whether tools used by federal teams are accessible and approachable for non-federal users. We critically assessed tools for evaluating postfire landscapes that are used by federal teams through a scoring system for practicality of use by private or community land managers. Each tool was scored based on three criteria: required inputs, required equipment, and available guidance. Tools were further characterized by scope, scale, use of Curve Numbers, and capacity to incorporate treatments. Results show that the Soil Burn Severity Datasheet, the Burned Area Reports Database, the Rule of Thumb by Kuyumjian, and USGS Regression Equations are most accessible for non-federal audiences. FERGI and HEC-HMS are the least transferable. Currently available postfire assessment tools are usable by non-federal audiences, with some more approachable than others. As new tools are developed, opportunities exist to build tools that are more accessible to more diverse user groups.
Wetlands are an ecologically important yet threatened plant community type in many natural areas. Inventory and monitoring are essential components of protecting, managing, and restoring wetland resources. However, many challenges currently exist for resource managers looking to perform a comprehensive inventory of wetlands throughout expansive, topographically complex, and/or remote natural areas. Here we present ongoing work in Great Smoky Mountains National Park (GRSM) that is addressing these challenges using spatial modeling to inform on-the-ground surveys. Wetland communities occur throughout GRSM at all elevations but tend to be relatively small and patchily distributed. While simple models based on low (<10%) slope are informative to wetland surveys at low elevations (<1067 m), such models become ineffective in steep topography at high elevations. To address this issue, we developed and implemented parkwide maximum entropy (Maxent) wetland habitat suitability models incorporating 24 environmental variables. Using these models to guide wetland survey efforts for three years, we identified and mapped 93 new wetland occurrences and more than doubled our previous high-elevation (≥1067 m) wetland inventory in roughly half the time. Maxent modeling is a relatively easy to use tool that can help resource managers plan, prioritize, and implement field inventories efficiently and effectively. We encourage natural areas managers to adopt similar spatial modeling approaches to guide the detection of unique, patchily distributed plant community types such as glades, barrens, balds, or rock outcrop communities.
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