Payments for ecosystem services (PES) programs are one prominent strategy to address economic externalities of resource extraction and commodity production, improving both social and ecological outcomes. But do PES and related incentive programs achieve that lofty goal? Along with considerable enthusiasm, PES has faced a wide range of substantial critiques. In this paper, we characterize seven major classes of concerns associated with common PES designs, and use these as inspiration to consider potential avenues for improvements in PES outcomes and uptake. The problems include (1) new externalities, (2) misplacement of rights and responsibilities, (3) crowding out existing motivations, (4) efficiency-equity tradeoffs, (5) monitoring costs, (6) limited applicability, and (7) top-down prescription/alienating agency. As currently practiced, many PES programs are thus of limited benefit and even potentially detrimental to sustainability. From this dire conclusion, we highlight several innovations that might be combined and extended in a novel approach to PES that may address all seven problems. Recognizing that PES necessarily articulate and even normalize values, our proposed approach entails designing these institutions intentionally to articulate rights and responsibilities conducive to sustainability-those we might collectively seek to entrench. Problems remain, and new ones may arise, but the proposed approach may offer a way to reimagine PES as a major social and economic tool for enabling sustainable relationships with nature, conserving and restoring ecosystems and their benefits for people now and in the future.

The upstream passage of sturgeon (family Acipenseridae) past barriers such as dams has become a concern of fisheries managers in California. Knowledge about the swimming abilities of adult sturgeon species, particularly with relationship to fish ladders, is limited. Wild adult white sturgeon Acipenser transmontanus (n = 25; total length, 135–198 cm) captured in the San Francisco Estuary and Yolo Bypass toe drain were swum in a variable‐speed aluminum flume (24.4 m long × 2.1 m wide × 1.4 m deep) to evaluate swimming behavior around simulated fish‐ladder‐type partial baffles. Four baffle types (one horizontal ramp and three different vertical slot designs) set in two configurations were tested at three velocity regimes (velocity range around baffles, 0.28–2.52 m/s). In general, faster velocities (0.76–1.07 m/s) cued fish to swim upstream sooner (≤100 s). Among the baffle types, the percentage of successful passage was variable, and no statistically significant pattern was detected. The tail‐beat frequency of fish significantly increased in the high‐velocity (to 2.52 m/s) regions of the flume adjacent to the energy‐dissipating baffles, where sturgeon were able to pass by swimming in bursts, followed by a resting and recovery period in slower water. Successful white sturgeon passage structures should incorporate rapid‐velocity (e.g., 0.84–2.52‐m/s) sections between somewhat slower (e.g., 0.51–0.68‐m/s) sections for rest and recovery.

Concern over passage of sturgeon barriers, has focused attention on fishway design that accommodates its swimming performance. In order to evaluate swimming performance, regarding fish ladder type partial barriers, wild adult sturgeons, Acipenser transmontanus; 121-176 cm fork length, were captured in the San Francisco Bay Estuary and Yolo Bypass toe drain. Hydrodynamic forces and kinematic parameters for swimming performance data were collected in a laboratory flume under three flow conditions through barriers and ramp. The experiments were conducted in a 24.4 m long, 2.1 m wide, and 1.62 m deep aluminum channel. Two geometric configurations of the laboratory model were designed based on channel characteristics that have been identified in natural river systems. At a given swimming speed and fish size, the highest guidance efficiencies of successful white sturgeon passage as a function of flow depth, flow velocity, turbulence intensity, Reynolds number, Froude number and shear velocity observed in the steady flow condition, tested with the horizontal ramp structure, occurred at an approach velocity of 0.33 ms -1 . The guidance efficiency of successful sturgeon passage increased both with increasing flow velocity and Froude number, and decreased both with the flow depth and the turbulence intensity. This study also provides evidence that tail beat frequency increases significantly with swimming speed, but tail beat frequency decreases with fish total length. Stride length increases both with swimming speed and fish total length. The importance of unsteady forces is expressed by the reduced frequency both with swimming speed and fish total length. Regression analysis indicates that swimming kinematic variables are explained by the swimming speed, the reduced frequency and the fish total length. The results emphasize the importance of fish ladder type patchiness when a fishway is designed for the passage of sturgeon.

Our study objective was to test passage performance of adult wild-caught white sturgeon Acipenser transmontanus (123-225 cm TL) in a simulated mid-section of a 24.4-m-long experimental fishway incorporating vertical barriers, a 4% bed slope, and a series of five, paired vertical baffles (with 0.61-m slot widths) to dissipate flowing-water kinetic energy as well as to provide guidance for upstream migration. Fish, in good physical condition, reaching the upstream end of our flume in both the low (50% of the fish) and high (48%) tailwater treatments exceeded that of fish in poor condition (5%). To assist in evaluating performance we examined the physiological stress responses of a small sample of these sturgeon. Blood samples from four, cannulated fish showed post-swimming peaks in hematocrit and plasma cortisol concentrations, compared with pre-swimming and (24-h) post-experiment levels. In addition, plasma pH showed decreases and mean plasma lactate showed increases post-swimming, indicating white-muscle recruitment. Overall, a relatively high percentage of adult white sturgeon in good physical condition, successfully ascended the sturgeon-compatible fishway and displayed burst-swimming-associated stress responses typical of many teleostean fishes, followed by complete recovery after 24 h.

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