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41.
IDW‐Plus: An ArcGIS Toolset for Calculating Spatially Explicit Watershed Attributes for Survey Sites 下载免费PDF全文
Erin E. Peterson Alan R. Pearse 《Journal of the American Water Resources Association》2017,53(5):1241-1249
Watershed characteristics such as land‐use and land‐cover affect stream condition at multiple scales, but it is widely accepted that conditions in close proximity to the stream or survey site tend to have a stronger influence. Although spatially weighted watershed metrics have existed for years, nonspatial lumped landscape metrics (i.e., areal mean or percentage) are still widely used because relatively few technical skills are needed to implement them. The Inverse Distance Weighted Percent Land Use for Streams (IDW‐Plus) custom ArcGIS toolset provides the functionality to efficiently calculate six spatially explicit watershed metrics which account for the Euclidean or flow length distance to the stream or outlet, as well as the probability for overland runoff. These include four distance‐weighted metrics, those being inverse Euclidean distance to the stream or outlet, and the inverse flow length to the stream or outlet. Two tools are also included to generate hydrologically active (i.e., runoff potential), inverse flow length to the stream or outlet metrics. We demonstrate the tools using real data from Southeast Queensland, Australia. We also provide detailed instructions, so readers can recreate the examples themselves before applying the tools to their own data. 相似文献
42.
Lirman D Gracias NR Gintert BE Gleason AC Reid RP Negahdaripour S Kramer P 《Environmental monitoring and assessment》2007,125(1-3):59-73
The recent decline in the condition of coral reef communities worldwide has fueled the need to develop innovative assessment
tools to document coral abundance and distribution rapidly and effectively. While most monitoring programs rely primarily
on data collected in situ by trained divers, digital photographs and video are used increasingly to extract ecological indicators, provide a permanent
visual record of reef condition, and reduce the time that divers spend underwater. In this study, we describe the development
and application of a video-based reef survey methodology based on an algorithm for image registration and the estimation of
image motion and camera trajectory. This technology was used to construct two-dimensional, spatially accurate, high-resolution
mosaics of the reef benthos at a scale of up to 400 m2. The mosaics were analyzed to estimate the size and percent cover of reef organisms and these ecological indicators of reef
condition were compared to similar measurements collected by divers to evaluate the potential of the mosaics as monitoring
tools. The ecological indicators collected by trained divers compared favorably with those measured directly from the video
mosaics. Five out of the eight categories chosen (hard corals, octocorals, Palythoa, algal turf, and sand) showed no significant differences in percent cover based on survey method. Moreover, no significant
differences based on survey method were found in the size of coral colonies. Lastly, the capability to extract the same reef
location from mosaics collected at different times proved to be an important tool for documenting change in coral abundance
as the removal of even small colonies (<10 cm in diameter) was easily documented. The two-dimensional video mosaics constructed
in this study can provide repeatable, accurate measurements on the reef-plot scale that can complement measurements on the
colony-scale made by divers and surveys conducted at regional scales using remote sensing tools. 相似文献
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Swails Erin Yang X. Asefi S. Hergoualc’h K. Verchot L. McRoberts R. E. Lawrence D. 《Mitigation and Adaptation Strategies for Global Change》2019,24(4):575-590
Mitigation and Adaptation Strategies for Global Change - Carbon dioxide (CO2) emissions from Southeast Asia peatlands are contributing substantially to global anthropogenic emissions to the... 相似文献
48.
Federal land management agencies, such as the USDA Forest Service, have expanded the role of recreation partners reflecting
constrained growth in appropriations and broader societal trends towards civic environmental governance. Partnerships with
individual volunteers, service groups, commercial outfitters, and other government agencies provide the USDA Forest Service
with the resources necessary to complete projects and meet goals under fiscal constraints. Existing partnership typologies
typically focus on collaborative or strategic alliances and highlight organizational dimensions (e.g., structure and process)
defined by researchers. This paper presents a partner typology constructed from USDA Forest Service partnership practitioners’
conceptualizations of 35 common partner types. Multidimensional scaling of data from unconstrained pile sorts identified 3
distinct cultural dimensions of recreation partners—specifically, partnership character, partner impact, and partner motivations—that
represent institutional, individual, and socio-cultural cognitive domains. A hierarchical agglomerative cluster analysis provides
further insight into the various domains of agency personnel’s conceptualizations. While three dimensions with high reliability
(RSQ = 0.83) and corresponding hierarchical clusters illustrate commonality between agency personnel’s partnership suppositions,
this study also reveals variance in personnel’s familiarity and affinity for specific partnership types. This real-world perspective
on partner types highlights that agency practitioners not only make strategic choices when selecting and cultivating partnerships
to accomplish critical task, but also elect to work with partners for the primary purpose of providing public service and
fostering land stewardship. 相似文献
49.
Brian M. Shamblin Mark G. Dodd Dean A. Bagley Llewellyn M. Ehrhart Anton D. Tucker Chris Johnson Raymond R. Carthy Russell A. Scarpino Erin McMichael David S. Addison Kristina L. Williams Michael G. Frick Stefanie Ouellette Anne B. Meylan Matthew H. Godfrey Sally R. Murphy Campbell J. Nairn 《Marine Biology》2011,158(3):571-587
The southeastern United States supports one of two large loggerhead turtle (Caretta caretta) nesting aggregations worldwide and is therefore critical to global conservation and recovery efforts for the species. Previous studies have established the presence of four demographically distinct nesting populations (management units) corresponding to beaches from (1) North Carolina through northeastern Florida, (2) peninsular Florida, (3) the Dry Tortugas, and (4) northwest Florida. Temporal and geographic genetic structure of the nesting aggregation was examined utilizing partial mitochondrial control region haplotype frequencies from 834 samples collected over the 2002 through 2008 nesting seasons from 19 beaches as well as previously published haplotype data. Most rookeries did not exhibit interannual genetic variation. However, the interannual variation detected did significantly impact the interpretation of spatial genetic structure in northeastern Florida. Based on pairwise F ST comparisons, exact tests of population differentiation, and analysis of molecular variance, the present study upholds the distinctiveness of the four currently recognized management units and further supports recognition of discrete central eastern, southern (southeastern and southwestern), and central western Florida management units. Further subdivision may be warranted, but more intensive genetic sampling is required. In addition, tools such as telemetry and mark-recapture are needed to complement genetic data and overcome limitations of genetic markers in resolving loggerhead turtle rookery connectivity in the southeastern USA. 相似文献
50.
Kellner JR Asner GP Kinney KM Loarie SR Knapp DE Kennedy-Bowdoin T Questad EJ Cordell S Thaxton JM 《Ecological applications》2011,21(6):2094-2104
Escape from natural enemies is a widely held generalization for the success of exotic plants. We conducted a large-scale experiment in Hawaii (USA) to quantify impacts of ungulate removal on plant growth and performance, and to test whether elimination of an exotic generalist herbivore facilitated exotic success. Assessment of impacted and control sites before and after ungulate exclusion using airborne imaging spectroscopy and LiDAR, time series satellite observations, and ground-based field studies over nine years indicated that removal of generalist herbivores facilitated exotic success, but the abundance of native species was unchanged. Vegetation cover <1 m in height increased in ungulate-free areas from 48.7% +/- 1.5% to 74.3% +/- 1.8% over 8.4 years, corresponding to an annualized growth rate of lambda = 1.05 +/- 0.01 yr(-1) (median +/- SD). Most of the change was attributable to exotic plant species, which increased from 24.4% +/- 1.4% to 49.1% +/- 2.0%, (lambda = 1.08 +/- 0.01 yr(-1)). Native plants experienced no significant change in cover (23.0% +/- 1.3% to 24.2% +/- 1.8%, lambda = 1.01 +/- 0.01 yr(-1)). Time series of satellite phenology were indistinguishable between the treatment and a 3.0-km2 control site for four years prior to ungulate removal, but they diverged immediately following exclusion of ungulates. Comparison of monthly EVI means before and after ungulate exclusion and between the managed and control areas indicates that EVI strongly increased in the managed area after ungulate exclusion. Field studies and airborne analyses show that the dominant invader was Senecio madagascariensis, an invasive annual forb that increased from < 0.01% to 14.7% fractional cover in ungulate-free areas (lambda = 1.89 +/- 0.34 yr(-1)), but which was nearly absent from the control site. A combination of canopy LAI, water, and fractional cover were expressed in satellite EVI time series and indicate that the invaded region maintained greenness during drought conditions. These findings demonstrate that enemy release from generalist herbivores can facilitate exotic success and suggest a plausible mechanism by which invasion occurred. They also show how novel remote-sensing technology can be integrated with conservation and management to help address exotic plant invasions. 相似文献