Management of Landscapes for Established Invasive Species

Long-term management strategies are invoked once an invasive species has become established and spread beyond feasible limits for eradication or containment. Although an invasive species may be well-established in small to large geographical areas, prevention of its spread to non-affected areas (e.g., sites, regions, and cross-continent) through early detection and monitoring is an important management activity. The level for management of established invasive species in the United States has increasingly shifted to larger geographical scales in the past several decades. Management of an invasive fish may occur at the watershed level in the western States, with watershed levels defined by their hydrologic unit codes (HUC) ranging from 2 digits at the coarsest level to 8 digits at the finest level (USGS 2018). Invasive plant management within national forests, grasslands, and rangelands can be implemented at the landscape level (e.g., Chambers et al. 2014), although management can still occur at the stand or base level. Landscapes in this chapter refer to areas of land bounded by large-scale physiographic features integrated with natural or man-made features that govern weather and disturbance patterns and limit frequencies of species movement (Urban et al. 1987). These are often at a large physical scale, such as the Great Basin.

Quantifying the Payments for Ecosystem Services among hydrologic units in Zhujiang River Basin, China based on the indicator of Optional Capacity Value

Ecosystem services (ES) are fundamental to human being’s livelihoods, production and survival. However, the spatial mismatch between ES supply and demand is a common phenomenon. Payments for Ecosystem Services (PES) provide a way to promote the complementary advantages and benefits equilibrium between ES supplier and beneficiary. At present, PES is mainly based on the tradeoff between the profit and loss of ecological conservation. The quantifying of PES mainly uses the opportunity cost of ES supplier and follows the principle of additionality, which neglects the benefits that arise from the basic (contrast to additional) ES experienced by ES beneficiary and ignores the rights and interests of ES supplier who supplies the basic ES. To resolve this problem, we proposed that we should set the value of ES experienced by ES beneficiary as the quantitative indicator of PES. Here, we introduced a new indicator (optional capacity value, OCV) to implement this idea. The ES OCV indicates the optional capacity of supporting the total value produced by human being’s economic and social activities provided by the total volume of an ES. In this paper, we calculated the ES OCV of water provision in Zhujiang River Basin (Pearl River Basin), China. Then, we discussed three scenarios of quantifying PES, based on the principles of (1) interests sharing and responsibilities bearing and (2) equal pay for equal work. The results showed that the ES OCV could describe the conditions that water resources in a hydrologic unit not only provide benefits to the hydrologic unit itself, but also provide benefits to downstream hydrologic units, and then could be a quantitative indicator for PES. This research provides a new PES scheme which would promote the coordinated development and ecological conservation among the regions with mismatch between ES supply and demand.

Multispecies and Watershed Approaches to Freshwater Fish Conservation

<em>Abstract</em>.—Native fish conservation areas (NFCAs) are watersheds where management emphasizes proactive conservation and restoration for long-term persistence of native fish assemblages while allowing for compatible uses. Native fish conservation areas are intended to complement traditional fisheries management approaches that are often reactive to population stressors and focused on single-species conservation efforts rather than complete assemblages. We identified potential NFCAs in the upper Snake River basin above Hells Canyon Dam using a process that ranked all subwatersheds (Hydrologic Unit Code 12) and used empirical data on distribution, abundance, and genetics for three native trout species (Bull Trout <em>Salvelinus confluentus</em>, Columbia River Redband Trout <em>Oncorhynchus mykiss gairdneri</em>, and Yellowstone Cutthroat Trout <em>O. clarkii bouvieri</em>, including the fine-spotted form) and both known occurrences and modeled potential distributions of native nongame fishes. Rankings also incorporated drainage network connectivity and land-protection status (e.g., national park, wilderness). Clusters of high-ranking subwatersheds were identified as potential NFCAs that were then classified according to the presence of nongame fishes identified as species of greatest conservation need in state wildlife action plans. The Pacific Creek and Goose Creek watersheds ranked high in the upper basin (above Shoshone Falls), and Little Jacks Creek and Squaw Creek ranked high in the lower basin. We then contrasted characteristics of a select few potential NFCAs, discuss the practical implementation and benefits of NFCAs for both fishes and other aquatic species in the upper Snake River basin, examined how the NFCA approach could enhance existing conservation partnerships, and discuss how designating select watersheds as NFCAs can create higher public awareness of the value of native fishes and other aquatic species and their habitats.

Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages

<i>Abstract.</i>—Fluvial threat assessments characterize the potential for fluvial habitat conditions to be degraded by differing types and intensities of anthropogenic activities occurring on the landscape, ultimately affecting stream biota. We present a threat assessment for fluvial habitats in Alaska based on six anthropogenic disturbance indices representing urbanization, agriculture/timber harvest, stream fragmentation, point-source pollution, infrastructure, and mines. These indices were combined to develop an overall index of contemporary threat of habitat alteration throughout Alaska using the 12-digit U.S. Geological Survey hydrologic unit code (HUC-12) framework (<i>n </i>= 13,997) and at a finer spatial resolution using local and network catchments for individual stream reaches within Southeast Alaska (<i>n </i>= 207,092). Overall, contemporary threat of habitat alteration indices showed that ~96% of fluvial habitats both statewide and for Southeast Alaska were at low or very low levels; however, anadromous fish habitats were under greater human pressure with nearly double the amount of moderately to severely disturbed habitats when compared to all fluvial habitats. We further evaluated potential future threats to fluvial habitats from mineral mining activities and climate change. More than 86% of existing mine claims statewide and 99% of claims in Southeast Alaska occur in areas of low and very low contemporary threat to fluvial habitats for anadromous fishes. Under climate change, July air temperatures are projected to increase ~1.9°C, on average, by mid-century within HUC-12s containing anadromous fish streams, indicating immense potential to warm streams with anadromous fishes within the state. This fluvial threat assessment demonstrates that overall threats from contemporary anthropogenic disturbance factors are generally low with localized areas of high intensity. However, future threats from mining and climate change have considerable potential to alter fluvial habitats for anadromous fishes in Alaska, particularly those currently unaltered by anthropogenic disturbances.

Past, current, and projected landscape configurational effects on streamflow within the Rocky River HUC-8 watershed of the Charlotte metropolitan region

This study examined past, current, and projected landscape configuration (LC) impacts on streamflow within a 3,553 square kilometer (km2) Hydrologic Unit Code (HUC)-8 Rocky River (RR) watershed of the Charlotte, North Carolina metropolitan region (CMR). Utilizing a monthly model, Thornthwaite Water Balance (TWB) simulations incorporating LC (blended contagion (CON)-adjusted curve numbers (CNs)) derived from two previous (2001, 2006) and one current (2011) US scale land cover/land use (LC/LU) time snapshots outperformed a blended original (ORG) CN watershed model during the 15-year (180-month) period from January 1999 to December 2013. Findings were confirmed using evaluations from several statistically based, hydrologic model performance predictors. Five-year comparisons of the 2001 time snapshot with the 2006 time snapshot and 2011 time snapshot indicated the least underestimation/overestimation of measured streamflow occurred during the 2001 time snapshot. This period had the highest measured runoff and points towards LC influences on streamflow simulation being potentially more quantifiable during periods of greater watershed precipitation. Watershed LC/LU and climatic data were also projected to the 2030 time snapshot under five different scenarios. Streamflow was projected to be about 2.6% higher in volume than what was estimated for the current (2011) time snapshot using a blended CON-adjusted TWB model.

A calibration-free, robust estimation of monthly land surface evapotranspiration rates for continental-scale hydrology

Continuous simulation of monthly evapotranspiration rates for 1979–2015 was performed by the latest, calibration-free version of the complementary relationship of evaporation over the conterminous United States. The results were compared to similar estimates of the WREVAP program and the North American Regional Reanalysis (NARR) project. Validation of the three methods was performed by the Parameter-Elevation Regressions on Independent Slopes Model precipitation and Hydrologic Unit Code level-6 runoff data. The present method outperforms the WREVAP and NARR estimates with a root-mean-square error (RMSE) of 89 mm yr−1, an R2 value of 0.87, an absolute bias (σ) of −5 mm yr−1, and slope (m) and intercept (c) values of 0.97 and 22 mm yr−1, respectively, for the best-fit line, in comparison to similar values (RMSE = 161 mm yr−1, R2 = 0.8, σ = 124 yr–1 mm yr−1, m = 0.88, c = 191 mm yr−1; and RMSE = 195 mm yr−1, R2 = 0.81, σ = 146 mm yr−1, m = 1.05, c = 120 mm yr−1) of the latter two methods. The value of the Priestley–Taylor (PT) coefficient was determined by inversion of the PT-equation via a model-independent identification of wet cells and their estimated surface temperatures.

Coastal Impervious Cover and Watershed Scale

Environmental planners seek techniques that will enable them to analyze impervious cover to develop sound management plans for coastal regions. The spatial scale in which impervious cover has traditionally been widely analyzed is mismatched to the fine-scale resolution needed for local environmental management. This study examines impervious cover in New Hanover County, North Carolina using LiDAR derived subwatersheds and United States Geological Survey (USGS) 14-digit hydrologic unit watersheds to evaluate potential scale-dependency of impervious cover estimates. Spatial analysis of impervious cover across multi-scale watersheds indicates that fine scale subwatersheds exhibit patterns not revealed with coarser watersheds. Spatial and cartographic analyses suggest that localized impervious development and its expansion in first-order drainages originating in coastal lagoon watersheds is more appropriately analyzed using fine-scale, LiDAR-derived watersheds. Results stress the importance of using scale in watershed management and hydrogeomorphic context to aid planners when making decisions involving impervious cover.