Introducing wetland offset markets under development-restoration conflicts: The role of public offset credit supply.

Wetland offset markets (WOMs) are increasingly applied worldwide as powerful tools for mitigating conflicts between wetland development and restoration. Reducing benefit uncertainty is key to promoting private restoration and introducing WOMs, which necessitates sufficient and stable price signals. Given that governments are important suppliers in WOMs, this article aims to explore the role of public offset credit (OC) supply in delivering and adjusting price signals during WOM formation and evolution. A general spatial agent-based wetland offset market model is built to simulate landowners' behavior, price dynamics, and WOM evolution under different public OC supply schemes. The results show that the spontaneous formation of WOMs is a time-consuming process. Price signals of public OCs reduce price fluctuations at the early stage of WOMs. This price stabilizing effect can cause a long-term reduction in benefit uncertainty perceived by landowners. Therefore, public OCs can facilitate WOM formation either through the supply side with high supply prices or through the demand side with low supply prices. During the entire WOM evolution process, due to landowners' readaptation, cheap public OCs can cause significant market fluctuations following the ceasing of cheap public supplies. The impacts of public OC on wetland development and restoration might change over time, and the suitability of public OC supplies under different long-term wetland management preferences was analyzed. These findings can further the understanding of the process of introducing a new market mechanism, such as WOMs, and the role of the government as a supplier. The research results provide insights for WOM practices, public restoration and OC supply scheme design, and wetland development-restoration conflict coordination.

Flexibility trade-offs in conservation offsets.

Conservation offsets promise cost-effective conservation of biodiversity, especially under economic and environmental change, because they represent a more flexible approach to biodiversity conservation, allowing for the economic development of ecologically valuable land provided that this development is offset by restoration of previously developed areas. The level of flexibility is determined by the trading rules. Lax rules allow for more flexibility, which promises cost savings, but will likely lead to unintended loss of biodiversity. I analyzed the trade-off between economic costs and ecological benefits (biodiversity conservation) in biodiversity offsetting with an ecological-economic model that considered the three main types of offset flexibility: spatial, temporal, and ecosystem type. I sought to examine the influence of ecological and economic conditions on offset flexibility trade-offs. Large variation in the conservation costs and small costs of habitat restoration strongly increased trading activity and reduced the ecological benefit. The ecological benefit was most sensitive to spatial flexibility when a short range of ecological interaction was considered. At a large interaction range, spatial flexibility delivered large cost savings without overly reducing the ecological benefit. Risks and time lags associated with habitat restoration favored an offsetting scheme in which credits are awarded with the initiation of restoration projects rather than their successful completion-given appropriate offsetting multipliers were chosen. Altogether, under scarce resources, the level of flexibility in an offsetting scheme should be chosen by carefully balancing ecological benefits and economic costs.

Compromisos de flexibilidad en las compensaciones por conservación Resumen Las compensaciones por conservación prometen conservar la biodiversidad de forma rentable, especialmente de frente al cambio ambiental y económico. Ya que representan una estrategia más flexible para la conservación de la biodiversidad, esto permite el desarrollo económico de suelo con valor ecológico siempre y cuando este desarrollo esté compensado por la restauración de áreas con desarrollo previo. El nivel de flexibilidad está determinado por las reglas de intercambio. Las reglas laxas permiten una mayor flexibilidad, que promete ahorros, pero probablemente derive en la pérdida no intencionada de la biodiversidad. Analicé los compromisos entre los costos económicos y los beneficios ecológicos (conservación de la biodiversidad) en las compensaciones por biodiversidad con un modelo ecológico-económico que consideraba los tres tipos principales de flexibilidad: espacial, temporal y por tipo de ecosistema. Traté de examinar la influencia de las condiciones ecológicas y económicas sobre los compromisos de flexibilidad en las compensaciones. Una gran variación en los costos de conservación y los pequeños costos de la restauración del hábitat incrementaron fuertemente la actividad de intercambio y redujeron el beneficio ecológico. El beneficio ecológico fue más sensible a la flexibilidad espacial cuando consideré un corto alcance de la interacción ecológica. Con un alcance extenso, la flexibilidad espacial ofreció grandes ahorros son reducir por mucho el beneficio ecológico. Los riesgos y retrasos temporales asociados con la restauración del hábitat favorecieron un esquema de compensaciones en el que los créditos se otorgan al inicio del proyecto de restauración en lugar de con la conclusión exitosa del mismo-siempre y cuando se hayan elegido multiplicadores de compensación adecuados. En conjunto, si se tienen pocos recursos, el nivel de flexibilidad en un esquema de compensaciones debería elegirse con un balance cuidadoso entre los beneficios ecológicos y los costos económicos.

Large-scale PVA modeling of insects in cultivated grasslands: The role of dispersal in mitigating the effects of management schedules under climate change.

In many species, dispersal is decisive for survival in a changing climate. Simulation models for population dynamics under climate change thus need to account for this factor. Moreover, large numbers of species inhabiting agricultural landscapes are subject to disturbances induced by human land use. We included dispersal in the HiLEG model that we previously developed to study the interaction between climate change and agricultural land use in single populations. Here, the model was parameterized for the large marsh grasshopper (LMG) in cultivated grasslands of North Germany to analyze (1) the species development and dispersal success depending on the severity of climate change in subregions, (2) the additional effect of grassland cover on dispersal success, and (3) the role of dispersal in compensating for detrimental grassland mowing. Our model simulated population dynamics in 60-year periods (2020-2079) on a fine temporal (daily) and high spatial (250 × 250 m2) scale in 107 subregions, altogether encompassing a range of different grassland cover, climate change projections, and mowing schedules. We show that climate change alone would allow the LMG to thrive and expand, while grassland cover played a minor role. Some mowing schedules that were harmful to the LMG nevertheless allowed the species to moderately expand its range. Especially under minor climate change, in many subregions dispersal allowed for mowing early in the year, which is economically beneficial for farmers. More severe climate change could facilitate LMG expansion to uninhabited regions but would require suitable mowing schedules along the path. These insights can be transferred to other species, given that the LMG is considered a representative of grassland communities. For more specific predictions on the dynamics of other species affected by climate change and land use, the publicly available HiLEG model can be easily adapted to the characteristics of their life cycle.

Coherent Transfer of Transverse Optical Momentum to the Motion of a Single Trapped Ion.

Using a structured light beam carrying orbital angular momentum, we demonstrate excitation of the center-of-mass motion of a single atom in the transverse direction to the beam's propagation. This interaction enables quantum control of atomic motion in all axes with a single beam direction, which leads to applications in quantum computing and simulations with ion crystals. Here we demonstrate all the key features required for these applications, namely, coherent dynamics and strong carrier suppression in a configuration with the ion centered in the beam, which allows for single ion addressing and also provides robustness against pointing instabilities. To quantify transverse momentum transfer, we observe coherent dynamics on the sidebands of the S_{1/2} to D_{5/2} transition near 729 nm of a singly charged ^{40}Ca^{+} ion, cooled near the ground state of motion in the 3D harmonic potential of a Paul trap, and placed at the center of a first-order Laguerre-Gaussian beam. Exchange of quanta in the perpendicular direction to the beam's wave vector k is observed with a centered vortex shaped beam, together reduction of the parasitic carrier excitation by a factor of 40. This is in sharp contrast to the vanishing spin-motion coupling at the center of the Gaussian beam. Further, we characterize the coherent interaction by an effective transverse Lamb-Dicke factor η_{⊥}^{exp}=0.0062(5) which is in agreement with our theoretical prediction η_{⊥}^{theo}=0.0057(1).

Optical Superresolution Sensing of a Trapped Ion's Wave Packet Size.

We demonstrate superresolution optical sensing of the size of the wave packet of a single trapped ion. Our method extends the well-known ground state depletion (GSD) technique to the coherent regime. Here, we use a hollow beam to strongly saturate a coherently driven dipole-forbidden transition around a subdiffraction limited area at its center and observe state dependent fluorescence. By spatially scanning this laser beam over a single trapped ^{40}Ca^{+} ion, we are able to measure the wave packet sizes of cooled ions. Using a depletion beam waist of 4.2(1) µm we reach a spatial resolution which allows us to determine a wave packet size of 39(9) nm for a near ground state cooled ion. This value matches an independently deduced value of 32(2) nm, calculated from resolved sideband spectroscopy measurements. Finally, we discuss the ultimate resolution limits of our adapted GSD imaging technique in view of applications to direct quantum wave packet imaging.

A quantitative approach for the design of robust and cost-effective conservation policies under uncertain climate change: The case of grasshopper conservation in Schleswig-Holstein, Germany.

Climate is a major determinant of the world's distribution of biodiversity and species ranges are expected to shift as the climate changes. For conservation policies to be cost-effective in the long run these changes need to be taken into account. To some extent, policies can be adapted over time, but transaction costs, lock-in effects and path dependence limit the extent to which such adaptation is possible. Thus it is desirable that conservation policies be designed so that they are cost-effective in the long run even without future adaptations. Given that the future climate change is highly uncertain, the policies need to be robust to climatic uncertainty. In this paper we present an approach for the robustness analysis with regard to the cost-effectiveness of conservation policies in the face of uncertain climate change. The approach is applied to the conservation of a grasshopper species in the German federal state of Schleswig-Holstein. For the assessment of the cost-effectiveness of considered policies we develop a climate-ecological-economic model. We show that in the near future all considered policies have a similar level of robustness, while in the more distant future the policies differ substantially in their robustness and a trade-off emerges between the expected performance and robustness of a policy.

Compact embedded device for lock-in measurements and experiment active control.

We present a multi-purpose toolkit for digital processing, acquisition, and feedback control designed for physics labs. The kit provides in a compact device the functionalities of several instruments: function generator, oscilloscope, lock-in amplifier, proportional-integral-derivative filters, ramp scan generator, and a lock-control. The design combines field-programmable-gate-array processing and microprocessor programing to get precision, ease of use, and versatility. It can be remotely operated through the network with different levels of control: from simple off-the-shelf Web graphical user interface to remote script control or in-device programmed operation. Three example applications are presented in this work on laser spectroscopy and laser locking experiments. The examples include side-fringe locking, peak locking through lock-in demodulation, and complete in-device Pound-Drever-Hall modulation and demodulation at 31.25 MHz and advanced acquisition examples like real-time data streaming for remote storage.

Generating spatially optimized habitat in a trade-off between social optimality and budget efficiency.

Auctions have been proposed as alternatives to payments for environmental services when spatial interactions and costs are better known to landowners than to the conservation agency (asymmetric information). Recently, an auction scheme was proposed that delivers optimal conservation in the sense that social welfare is maximized. I examined the social welfare and the budget efficiency delivered by this scheme, where social welfare represents the difference between the monetized ecological benefit and the conservation cost incurred to the landowners and budget efficiency is defined as maximizing the ecological benefit for a given conservation budget. For the analysis, I considered a stylized landscape with land patches that can be used for agriculture or conservation. The ecological benefit was measured by an objective function that increases with increasing number and spatial aggregation of conserved land patches. I compared the social welfare and the budget efficiency of the auction scheme with an agglomeration payment, a policy scheme that considers spatial interactions and that was proposed recently. The auction delivered a higher level of social welfare than the agglomeration payment. However, the agglomeration payment was more efficient budgetarily than the auction, so the comparative performances of the 2 schemes depended on the chosen policy criterion-social welfare or budget efficiency. Both policy criteria are relevant for conservation. Which one should be chosen depends on the problem at hand, for example, whether social preferences should be taken into account in the decision of how much money to invest in conservation or whether the available conservation budget is strictly limited.

Cost-effectiveness of conservation payment schemes for species with different range sizes.

Payments to compensate landowners for carrying out costly land-use measures that benefit endangered biodiversity have become an important policy instrument. When designing such payments, it is important to take into account that spatially connected habitats are more valuable for many species than isolated ones. One way to incentivize provision of connected habitats is to offer landowners an agglomeration bonus, that is, a bonus on top of payments they are receiving to conserve land if the land is spatially connected. Researchers have compared the cost-effectiveness of the agglomeration bonus with 2 alternatives: an all-or-nothing, agglomeration payment, where landowners receive a payment only if the conserved land parcels have a certain level of spatial connectivity, and a spatially homogeneous payment, where landowners receive a payment for conserved land parcels irrespective of their location. Their results show the agglomeration bonus is rarely the most cost-effective option, and when it is, it is only slightly better than one of the alternatives. This suggests that the agglomeration bonus should not be given priority as a policy design option. However, this finding is based on consideration of only 1 species. We examined whether the same applied to 2 species, one for which the homogeneous payment is best and the other for which the agglomeration payment is most cost-effective. We modified a published conceptual model so that we were able to assess the cost-effectiveness of payment schemes for 2 species and applied it to a grassland bird and a grassland butterfly in Germany that require the same habitat but have different spatial-connectivity needs. When conserving both species, the agglomeration bonus was more cost-effective than the agglomeration and the homogeneous payment; thus, we showed that as a policy the agglomeration bonus is a useful conservation-payment option.

Rapid viability analysis for metapopulations in dynamic habitat networks.

For land-use planning, numerically fast and easily applicable tools are urgently needed that allow us to assess how landscape structure and dynamics affect biodiversity. To date, such tools exist only for static landscapes. We provide an analytical formula for the mean lifetime of species in fragmented and dynamic habitat networks where habitat patches may be destroyed and created elsewhere. The formula is able to consider both patch size heterogeneity and dynamics additionally to patch number and connectivity. It is validated through comparison with a dynamic and spatially explicit simulation model. It can be used for the optimization of spatio-temporal land-use patterns in real landscapes and for advancing our general understanding of key processes affecting the survival of species in fragmented heterogeneous dynamic landscapes.

Predicting metapopulation lifetime from macroscopic network properties.

This paper presents a comparatively simple approximation formula for the mean life time of a metapopulation in a habitat network where habitat patch arrangement may be irregular and patch sizes differ. It is based on previous work on the development of an analytical approximation formula by Frank and Wissel [K. Frank, C. Wissel, A formula for the mean lifetime of metapopulations in heterogeneous landscapes, Am. Nat. 159 (2002) 530] and extends it by abstracting from individual patch locations. The mean metapopulation lifetime is expressed as a function of four macroscopic network properties: the ratio of dispersal range and network size, the ratio of range of environmental correlation and network size, and the total number and (geometric mean) size of the patches. The analysis takes into account that (ceteris paribus) patches close to the boundary of the habitat network contribute less to metapopulation survival than patches close to the centre of the network. Ignoring this fact can lead to a substantial overestimation of the mean metapopulation lifetime. Due to its numerical simplicity, the formula can be used as a conservation objective function even in complex network design problems where the number of patches to be allocated is very large. Numerical tests of the formula show that it performs very well within a wide range of network structures.

Designing cost-effective payments for conservation measures to generate spatiotemporal habitat heterogeneity.

Many endangered species depend on certain types of agricultural or other forms of human land use. To conserve such species, schemes are set up in which land users receive payments for voluntarily managing their land in a biodiversity-enhancing manner. We developed a model-based framework for designing cost-effective payment schemes that generate spatiotemporal habitat heterogeneity to maximize the survival of multiple species under budget constraints. The framework integrates ecological and economic knowledge and consists of the derivation of an ecological benefit function and a budget function that are then combined to determine the cost-effective degree of spatiotemporal habitat heterogeneity. The ecological benefit function considers the timing of conservation measures, the induced habitat dynamics, and different degrees of substitutability among species. The budget function considers that the conservation agency may lack information about land users' individual conservation costs and personal attitudes and that land users can choose among different conservation measures. We applied the framework to a case study of grassland management, where the survival of three endangered species protected by the EU Habitats Directive depends on different types of land use. The lack of information available to the agency and the choice options of land users reduced the amount of conservation that can be financed with a given budget. Neglecting such findings may lead to an overestimation of the benefits of conservation programs.

Integrating economic costs into the analysis of flexible conservation management strategies.

Flexible conservation management, where measures (e.g., mowing of meadows, removing invasive species) are selected in each decision period depending on the current state of the ecological system, is generally perceived as superior to fixed management, where the same measure is applied in each decision period independent of the current state of the system. In past comparisons of fixed and flexible conservation strategies the additional costs that arise only in flexible strategies have usually been ignored. In this paper, we present a framework to integrate costs of flexible management into the evaluation of flexible conservation strategies. Using the example of an endangered butterfly species we demonstrate that the costs of flexible management may reverse the rank order of flexible and fixed conservation strategies, such that fixed strategies may lead to better ecological results than flexible ones for the same financial budget.

Ecological-economic modeling for biodiversity management: potential, pitfalls, and prospects.

Ecologists and economists both use models to help develop strategies for biodiversity management. The practical use of disciplinary models, however can be limited because ecological models tend not to address the socioeconomic dimension of biodiversity management, whereas economic models tend to neglect the ecological dimension. Given these shortcomings of disciplinary models, there is a necessity to combine ecological and economic knowledge into ecological-economic models. It is insufficient if scientists work separately in their own disciplines and combine their knowledge only when it comes to formulating management recommendations. Such an approach does not capture feedback loops between the ecological and the socioeconomic systems. Furthermore, each discipline poses the management problem in its own way and comes up with its own most appropriate solution. These disciplinary solutions, however, are likely to be so different that a combined solution considering aspects of both disciplines cannot be found. Preconditions for a successful model-based integration of ecology and economics include (1) an in-depth knowledge of the two disciplines, (2) the adequate identification and framing of the problem to be investigated, and (3) a common understanding between economists and ecologists of modeling and scale. To further advance ecological-economic modeling the development of common benchmarks, quality controls, and refereeing standards for ecological-economic models is desirable.

Multicriteria evaluation of simulated logging scenarios in a tropical rain forest.

Forest growth models are useful tools for investigating the long-term impacts of logging. In this paper, the results of the rain forest growth model FORMIND were assessed by a multicriteria decision analysis. The main processes covered by FORMIND include tree growth, mortality, regeneration and competition. Tree growth is calculated based on a carbon balance approach. Trees compete for light and space; dying large trees fall down and create gaps in the forest. Sixty-four different logging scenarios for an initially undisturbed forest stand at Deramakot (Malaysia) were simulated. The scenarios differ regarding the logging cycle, logging method, cutting limit and logging intensity. We characterise the impacts with four criteria describing the yield, canopy opening and changes in species composition. Multicriteria decision analysis was used for the first time to evaluate the scenarios and identify the efficient ones. Our results plainly show that reduced-impact logging scenarios are more 'efficient' than the others, since in these scenarios forest damage is minimised without significantly reducing yield. Nevertheless, there is a trade-off between yield and achieving a desired ecological state of logged forest; the ecological state of the logged forests can only be improved by reducing yields and enlarging the logging cycles. Our study also demonstrates that high cutting limits or low logging intensities cannot compensate for the high level of damage caused by conventional logging techniques.