TY - JOUR T1 - Comparing the effects of climate and land use on surface water quality using future watershed scenarios JF - Science of the Total Environment Y1 - 2019 A1 - Motew, Melissa A1 - Chen, Xi A1 - Carpenter, Stephen R. A1 - Booth, Eric G. A1 - Seifert, Jenny A1 - Qiu, Jiangxiao A1 - Loheide, Steven P. A1 - Turner, Monica G. A1 - Zipper, Samuel C. A1 - Kucharik, Christopher J. KW - climate KW - land use KW - Manure KW - phosphorus KW - Surface water quality KW - Watershed AB - Eutrophication of freshwaters occurs in watersheds with excessive pollution of phosphorus (P). Factors that affect P cycling and transport, including climate and land use, are changing rapidly and can have legacy effects, making future freshwater quality uncertain. Focusing on the Yahara Watershed (YW) of southern Wisconsin, USA, an intensive agricultural landscape, we explored the relative influence of land use and climate on three indicators of water quality over a span of 57 years (2014–2070). The indicators included watershed-averaged P yield from the land surface, direct drainage P loads to a lake, and average summertime lake P concentration. Using biophysical model simulations of future watershed scenarios, we found that climate exerted a stronger influence than land use on all three indicators, yet land use had an important role in influencing long term outcomes for each. Variations in P yield due to land use exceeded those due to climate in 36 of 57 years, whereas variations in load and lake total P concentration due to climate exceeded those due to land use in 54 of 57 years, and 52 of 57 years, respectively. The effect of land use was thus strongest for P yield off the landscape and attenuated in the stream and lake aquatic systems where the influence of weather variability was greater. Overall these findings underscore the dominant role of climate in driving inter-annual nutrient fluxes within the hydrologic network and suggest a challenge for land use to influence water quality within streams and lakes over timescales less than a decade. Over longer timescales, reducing applications of P throughout the watershed was an effective management strategy under all four climates investigated, even during decades with wetter conditions and more frequent extreme precipitation events. VL - 693 SN - 0048-9697 UR - http://www.sciencedirect.com/science/article/pii/S0048969719334047 ER - TY - JOUR T1 - Management of minimum lake levels and impacts on flood mitigation: A case study of the Yahara Watershed, Wisconsin, USA JF - Journal of Hydrology Y1 - 2019 A1 - Chen, Xi A1 - Motew, Melissa M. A1 - Booth, Eric G. A1 - Zipper, Samuel C. A1 - Loheide, Steven P. A1 - Kucharik, Christopher J. KW - ecosystem services KW - Flood exposure assessment KW - Hydrologic model KW - Lake level management AB - Lake level regulation is commonly used to manage water resources and mitigate flood risk in watersheds with linked river–lake systems. In this study, we first assess exposure, in terms of both population and land area, to flooding impacts in the Yahara Watershed’s chain of four lakes in southern Wisconsin as affected by minimum lake level management. A flooding exposure assessment shows that the areas surrounding the upstream lakes, Mendota and Monona, have dense urban areas with high populations that are exposed to flooding; Waubesa has low elevations along its lakeshore, resulting in a large potential flooding area; and the most downstream lake, Kegonsa, has a large area of surrounding cropland that is exposed to flooding but impacts a limited population. We then use a linked modeling framework of a land surface model (Agro-IBIS) and a hydrologic-routing model (THMB) to simulate daily lake level over a study period of 1994–2013 in the Yahara Watershed with different minimum lake level management strategies. Modeling results show that the peak lake levels and corresponding exposed land area and population to flooding will decrease under a lower target minimum lake level. However, at the same time, the number of days that the lake level is below winter minimum will increase, which may adversely affect ecosystem health. In addition, our sensitivity analysis indicates that reducing target minimum lake levels will help mitigate flood risk in terms of both flood magnitude and frequency. Nevertheless, this must be balanced against the need to maintain adequately high lake levels for ecosystem services and recreational functions of the lakes. VL - 577 SN - 0022-1694 UR - http://www.sciencedirect.com/science/article/pii/S0022169419306407 JO - Journal of Hydrology ER - TY - JOUR T1 - Nonlinear groundwater influence on biophysical indicators of ecosystem services JF - Nature Sustainability Y1 - 2019 A1 - Qiu, Jiangxiao A1 - Zipper, Samuel C. A1 - Motew, Melissa A1 - Booth, Eric G. A1 - Kucharik, Christopher J. A1 - Loheide, Steven P. AB - Groundwater is a fundamental control on biophysical processes underpinning essential ecosystem services (ES). However, interactions and feedbacks among groundwater, climate and multiple ES remain less well understood. We investigated groundwater effects on a portfolio of food, water and biogeochemical ES indicators in an urbanizing agricultural watershed. Our results show that food production, water quality and quantity, and flood control are most sensitive to groundwater, with the strongest responses under wet and dry climate extremes. Climate mediates groundwater effects, such that several ES have synergies during dry climate, but trade-offs (groundwater increased some ES but declined others) under wet climate. There is substantial spatial heterogeneity in groundwater effects on ES, which is driven primarily by water table depth (WTD) and is also sensitive to soil texture and land cover. Most ES indicators respond nonlinearly to WTD when groundwater is within a critical depth (approximately 2.5 m) of land surface, indicating that small WTD changes can have disproportionately large effects on ES in shallow groundwater areas. Within this critical WTD, increasingly shallow groundwater leads to nonlinear increases in surface flood risk, sediment erosion and phosphorus yield; nonlinear decreases in drainage to the deep vadose zone and thus groundwater recharge; and bidirectional responses of crop and grass production, carbon storage and nitrate leaching. Our study illustrates the complex role of groundwater in affecting multiple ES and highlights that strategically managing groundwater may enhance ES resilience to climate extremes in shallow groundwater settings. SN - 2398-9629 UR - https://doi.org/10.1038/s41893-019-0278-2 JO - Nature Sustainability ER - TY - JOUR T1 - Scale-dependent interactions between tree canopy cover and impervious surfaces reduce daytime urban heat during summer JF - Proceedings of the National Academy of Sciences Y1 - 2019 A1 - Ziter, Carly D. A1 - Pedersen, Eric J. A1 - Kucharik, Christopher J. A1 - Turner, Monica G. KW - air temperature KW - ecosystem services KW - landscape context KW - urban forest KW - urban heat island AB - Cities worldwide are experiencing record-breaking summer air temperatures, with serious consequences for people. Increased tree cover is suggested as a climate adaptation strategy, but the amount of tree canopy cover needed to counteract higher temperatures associated with impervious surface cover is not known. We used a bicycle-mounted measurement system to quantify the interaction of canopy cover and impervious surface cover on urban air temperature. Daytime air temperature was substantially reduced with greater canopy cover (≥40%) at the scale of a typical city block (60–90 m), especially on the hottest days. However, reducing impervious surfaces remained important for lowering nighttime temperatures. Results can guide strategies for increasing tree cover to mitigate daytime urban heat and improve residents’ well-being.As cities warm and the need for climate adaptation strategies increases, a more detailed understanding of the cooling effects of land cover across a continuum of spatial scales will be necessary to guide management decisions. We asked how tree canopy cover and impervious surface cover interact to influence daytime and nighttime summer air temperature, and how effects vary with the spatial scale at which land-cover data are analyzed (10-, 30-, 60-, and 90-m radii). A bicycle-mounted measurement system was used to sample air temperature every 5 m along 10 transects (∼7 km length, sampled 3–12 times each) spanning a range of impervious and tree canopy cover (0–100%, each) in a midsized city in the Upper Midwest United States. Variability in daytime air temperature within the urban landscape averaged 3.5 °C (range, 1.1–5.7 °C). Temperature decreased nonlinearly with increasing canopy cover, with the greatest cooling when canopy cover exceeded 40%. The magnitude of daytime cooling also increased with spatial scale and was greatest at the size of a typical city block (60–90 m). Daytime air temperature increased linearly with increasing impervious cover, but the magnitude of warming was less than the cooling associated with increased canopy cover. Variation in nighttime air temperature averaged 2.1 °C (range, 1.2–3.0 °C), and temperature increased with impervious surface. Effects of canopy were limited at night; thus, reduction of impervious surfaces remains critical for reducing nighttime urban heat. Results suggest strategies for managing urban land-cover patterns to enhance resilience of cities to climate warming. UR - http://www.pnas.org/content/early/2019/03/19/1817561116.abstract JO - Proc Natl Acad Sci USA ER - TY - JOUR T1 - Continuous separation of land use and climate effects on the past and future water balance JF - Journal of Hydrology Y1 - 2018 A1 - Zipper, Samuel C. A1 - Motew, Melissa A1 - Booth, Eric G. A1 - Chen, Xi A1 - Qiu, Jiangxiao A1 - Kucharik, Christopher J. A1 - Carpenter, Stephen R. A1 - Loheide II, Steven P. KW - Baseflow KW - Climate change KW - Evapotranspiration KW - Land use change KW - Streamflow KW - Urbanization AB - Understanding the combined and separate effects of climate and land use change on the water cycle is necessary to mitigate negative impacts. However, existing methodologies typically divide data into discrete (before and after) periods, implicitly representing climate and land use as step changes when in reality these changes are often gradual. Here, we introduce a new regression-based methodological framework designed to separate climate and land use effects on any hydrological flux of interest continuously through time, and estimate uncertainty in the contribution of these two drivers. We present two applications in the Yahara River Watershed (Wisconsin, USA) demonstrating how our approach can be used to understand synergistic or antagonistic relationships between land use and climate in either the past or the future: (1) historical streamflow, baseflow, and quickflow in an urbanizing subwatershed; and (2) simulated future evapotranspiration, drainage, and direct runoff from a suite of contrasting climate and land use scenarios for the entire watershed. In the historical analysis, we show that ∼60% of recent streamflow changes can be attributed to climate, with approximately equal contributions from quickflow and baseflow. However, our continuous method reveals that baseflow is significantly increasing through time, primarily due to land use change and potentially influenced by long-term increases in groundwater storage. In the simulation of future changes, we show that all components of the future water balance will respond more strongly to changes in climate than land use, with the largest potential land use effects on drainage. These results indicate that diverse land use change trajectories may counteract each other while the effects of climate are more homogeneous at watershed scales. Therefore, management opportunities to counteract climate change effects will likely be more effective at smaller spatial scales, where land use trajectories are unidirectional. VL - 565 UR - http://www.sciencedirect.com/science/article/pii/S0022169418306188 ER - TY - JOUR T1 - Current and historical land use influence soil‐based ecosystem services in an urban landscape JF - Ecological Applications Y1 - 2018 A1 - Ziter, Carly A1 - Turner, Monica G. KW - carbon KW - ecosystem services KW - Historical ecology KW - land‐use change KW - phosphorus KW - runoff regulation KW - saturated hydraulic conductivity KW - soil KW - Urban ecosystems KW - Water quality AB - Abstract Urban landscapes are increasingly recognized as providing important ecosystem services (ES) to their occupants. Yet, urban ES assessments often ignore the complex spatial heterogeneity and land?use history of cities. Soil?based services may be particularly susceptible to land?use legacy effects. We studied indicators of three soil?based ES, carbon storage, water quality regulation, and runoff regulation, in a historically agricultural urban landscape and asked (1) How do ES indicators vary with contemporary land cover and time since development? (2) Do ES indicators vary primarily among land?cover classes, within land?cover classes, or within sites? (3) What is the relative contribution of urban land?cover classes to potential citywide ES provision? We measured biophysical indicators (soil carbon [C], available phosphorus [P], and saturated hydraulic conductivity [Ks]) in 100 sites across five land?cover classes, spanning an ~125?year gradient of time since development within each land?cover class. Potential for ES provision was substantial in urban green spaces, including developed land. Runoff regulation services (high Ks) were highest in forests; water quality regulation (low P) was highest in open spaces and grasslands; and open spaces and developed land (e.g., residential yards) had the highest C storage. In developed land covers, both C and P increased with time since development, indicating effects of historical land?use on contemporary ES and trade?offs between two important ES. Among?site differences accounted for a high proportion of variance in soil properties in forests, grasslands, and open space, while residential areas had high within?site variability, underscoring the leverage city residents have to improve urban ES provision. Developed land covers contributed most ES supply at the citywide scale, even after accounting for potential impacts of impervious surfaces. Considering the full mosaic of urban green space and its history is needed to estimate the kinds and magnitude of ES provided in cities, and to augment regional ES assessments that often ignore or underestimate urban ES supply. SN - 1051-0761 UR - https://doi.org/10.1002/eap.1689 JO - Ecological Applications ER - TY - JOUR T1 - How do land-use legacies affect ecosystem services in United States cultural landscapes? JF - Landscape Ecology Y1 - 2017 A1 - Ziter, Carly A1 - Graves, Rose A. A1 - Turner, Monica G. KW - Agricultural ecosystems KW - Exurban ecosystems KW - Historical ecology KW - land-use change KW - Urban ecosystems AB - Landscape-scale studies of ecosystem services (ES) have increased, but few consider land-use history. Historical land use may be especially important in cultural landscapes, producing legacies that influence ecosystem structure, function, and biota that in turn affect ES supply. Our goal was to generate a conceptual framework for understanding when land-use legacies matter for ES supply in well-studied agricultural,urban, and exurban US landscapes. We synthesized illustrative examples from published literature in which landscape legacies were demonstrated or are likely to influence ES. We suggest three related conditions in which land-use legacies are important for understanding current ES supply. (1) Intrinsically slow ecological processes govern ES supply, illustrated for soil-based and hydrologic services impaired by slowly processed pollutants. (2) Time lags between land-use change and ecosystem responses delay effects on ES supply, illustrated for biodiversity-based services that may experience an ES debt. (3) Threshold relationships exist, such that changes in ES are difficult to reverse,and legacy lock-in disconnects contemporary landscapes from ES supply, illustrated by hydrologic services. Mismatches between contemporary landscape patterns and mechanisms underpinning ES supply yield unexpected patterns of ES. Today’s land-use decisions will generate tomorrow’s legacies, and ES will be affected if processes underpinning ES are affected by land-use legacies. Research priorities include understanding effects of urban abandonment, new contaminants, and interactions of land-use legacies and climate change. Improved understanding of historical effects will improve management of contemporary ES, and aid in decision-making as new challenges to sustaining cultural landscapes arise. SN - 1572-9761 UR - http://dx.doi.org/10.1007/s10980-017-0545-4 JO - Landscape Ecology ER - TY - JOUR T1 - The Influence of Legacy P on Lake Water Quality in a Midwestern Agricultural Watershed JF - Ecosystems Y1 - 2017 A1 - Motew, Melissa A1 - Chen, Xi A1 - Booth, Eric G. A1 - Carpenter, Stephen R. A1 - Pinkas, Pavel A1 - Zipper, Samuel C. A1 - Loheide, Steven P. A1 - Donner, Simon D. A1 - Tsuruta, Kai A1 - Vadas, Peter A. A1 - Kucharik, Christopher J. AB - Decades of fertilizer and manure applications have led to a buildup of phosphorus (P) in agricultural soils and sediments, commonly referred to as legacy P. Legacy P can provide a long-term source of P to surface waters where it causes eutrophication. Using a suite of numerical models, we investigated the influence of legacy P on water quality in the Yahara Watershed of southern Wisconsin, USA. The suite included Agro-IBIS, a terrestrial ecosystem model; THMB, a hydrologic and nutrient routing model; and the Yahara Water Quality Model which estimates water quality indicators in the Yahara chain of lakes. Using five alternative scenarios of antecedent P storage (legacy P) in soils and channels under historical climate conditions, we simulated outcomes of P yield from the landscape, lake P loading, and three lake water quality indicators. Legacy P had a significant effect on lake loads and water quality. Across the five scenarios for Lake Mendota, the largest and most upstream lake, average P yield (kg ha−1) varied by −41 to +22%, P load (kg y−1) by −35 to +14%, summer total P (TP) concentration (mg l−1) by −25 to +12%, Secchi depth (m) by −7 to +3%, and the probability of hypereutrophy by −67 to +34%, relative to baseline conditions. The minimum storage scenario showed that a 35% reduction in present-day loads to Lake Mendota corresponded with a 25% reduction in summer TP and smaller reductions in the downstream lakes. Water quality was more vulnerable to heavy rainfall events at higher amounts of P storage and less so at lower amounts. Increases in heavy precipitation are expected with climate change; therefore, water quality could be protected by decreasing P reserves. SN - 1435-0629 UR - http://dx.doi.org/10.1007/s10021-017-0125-0 JO - Ecosystems ER - TY - JOUR T1 - Quantifying indirect groundwater-mediated effects of urbanization on agroecosystem productivity using MODFLOW-AgroIBIS (MAGI), a complete critical zone model JF - Ecological Modeling Y1 - 2017 A1 - Zipper, Samuel C. A1 - Soylu, Mehmet Evren A1 - Kucharik, Christopher J. A1 - Loheide II, Steven P. KW - agroecosystem modeling KW - Dynamic vegetation models KW - Groundwater recharge KW - Groundwater-land surface coupling KW - Land use change KW - Urbanization AB - Sustainably accommodating future population growth and meeting global food requirements requires understanding feedbacks between ecosystems and belowground hydrological processes. Here, we introduce MODFLOW-AgroIBIS (MAGI), a new dynamic ecosystem model including groundwater flow, and use MAGI to explore the indirect impacts of land use change (urbanization) on landscape-scale agroecosystem productivity (corn yield). We quantify the degree to which urbanization can indirectly impact yield in surrounding areas by changing the amount of groundwater recharge locally and the water table dynamics at landscape scales. We find that urbanization can cause increases or decreases in yield elsewhere, with changes up to approximately +/− 40% under the conditions simulated due entirely to altered groundwater-land surface interactions. Our results indicate that land use change in upland areas has the largest impact on water table depth over the landscape. However, there is a spatial mismatch between areas with the largest water table response to urbanization elsewhere (upland areas) and locations with the strongest yield response to urbanization elsewhere (midslope areas). This mismatch arises from differences in baseline water table depth prior to urbanization. Yield response to urbanization in lowland areas is relatively localized despite large changes to the vertical water balance due to stabilizing ecohydrological feedbacks between root water uptake and lateral groundwater flow. These results demonstrate that hydrological impacts of land use change can propagate through subsurface flow to indirectly impact surrounding ecosystems, and these subsurface connections should be considered when planning land use at a landscape scale to avoid negative outcomes associated with land use change. VL - 359 SN - 0304-3800 UR - http://www.sciencedirect.com/science/article/pii/S0304380017300789 JO - Ecological Modelling ER - TY - JOUR T1 - Urban heat island-induced increases in evapotranspirative demand JF - Geophysical Research Letters Y1 - 2017 A1 - Zipper, Samuel C. A1 - Schatz, Jason A1 - Kucharik, Christopher J. A1 - Loheide, Steven P. KW - ecohydrology KW - plant water use KW - reference evapotranspiration KW - urban climatology KW - urban ecology KW - urban heat island KW - Urban systems KW - Water supply AB - Although the importance of vegetation in mitigating the urban heat island (UHI) is known, the impacts of UHI-induced changes in micrometeorological conditions on vegetation are not well understood. Here we show that plant water requirements are significantly higher in urban areas compared to rural areas surrounding Madison, WI, driven by increased air temperature with minimal effects of decreased air moisture content. Local increases in impervious cover are strongly associated with increased evapotranspirative demand in a consistent manner across years, with most increases caused by elevated temperatures during the growing season rather than changes in changes in growing season length. Potential evapotranspiration is up to 10% higher due to the UHI, potentially mitigating changes to the water and energy balances caused by urbanization. Our results indicate that local-scale land cover decisions (increases in impervious cover) can significantly impact evapotranspirative demand, with likely implications for water and carbon cycling in urban ecosystems. SN - 1944-8007 UR - http://dx.doi.org/10.1002/2016GL072190 ER - TY - JOUR T1 - The biodiversity–ecosystem service relationship in urban areas: a quantitative review JF - Oikos Y1 - 2016 A1 - Ziter, Carly AB - By 2050, up to 75% of people globally will live in cities. Despite the potential ramifications of this urbanization for ecosystem services (ES), and the importance of locally produced ES for the health and wellbeing of urban residents, syntheses addressing the underlying ecology of ES provision rarely include urban areas. Here, I conduct a quantitative review of urban ES studies in the ecological literature, synthesizing trends across the discipline. I also quantify the extent to which this work considers the organisms and ecosystem components responsible for ES provision using two approaches: assessment of biodiversity–ES relationships, and an adaptation of the service provider concept. The majority of urban ES studies were conducted in western, developed countries, and typically assessed a single service in a single city – largely ignoring ES synergies and tradeoffs, and cross-city comparisons. While several different ES are studied in urban ecosystems, the field is dominated by weather and climate-related regulating services, with assessments of cultural services particularly lacking. Most studies described a habitat type as the service provider; however, studies that considered the biodiversity–ES relationship were more likely to identify a specific functional group, community, or population as the key provider of an ES. The biodiversity–ES relationship itself was most frequently characterized as dependent on the composition of species, functional traits, or structures, rather than correlated with the magnitude of any specific biodiversity metric. While the study of ES in urban ecosystems is increasing, there exists considerable room for further research. Future studies would benefit by expanding the number and categories of ES assessed within and across cities, as well as broadening the geographical scope of urban ES research. Biodiversity–ES assessments in urban ecosystems would also benefit from an expansion of the biodiversity types considered, particularly regarding non-species based approaches, and consideration of non-native and invasive species. VL - 125 IS - 6 ER - TY - JOUR T1 - Drought effects on US maize and soybean production: spatiotemporal patterns and historical changes JF - Environmental Research Letters Y1 - 2016 A1 - Samuel C Zipper A1 - Jiangxiao Qiu A1 - Christopher J Kucharik KW - agriculture KW - Climate change KW - drought KW - food production KW - SPEI KW - yield variability AB - Maximizing agricultural production on existing cropland is one pillar of meeting future global foodsecurity needs. To close crop yield gaps, it is critical to understand how climate extremes such asdrought impact yield. Here, we use gridded, daily meteorological data and county-level annual yielddata to quantify meteorological drought sensitivity of US maize and soybean production from 1958 to2007. Meteorological drought negatively affects crop yield over most US crop-producing areas, andyield is most sensitive to short-term (1–3 month) droughts during critical development periods fromJuly to August. While meteorological drought is associated with 13% of overall yield variability,substantial spatial variability in drought effects and sensitivity exists, with central andsoutheastern US becoming increasingly sensitive to drought over time. Our study illustratesfine-scale spatiotemporal patterns of drought effects, highlighting where variability in cropproduction is most strongly associated with drought, and suggests that management strategies thatbuffer against short-term water stress may be most effective at sustaining long-term cropproductivity. VL - 11 SN - 1748-9326 UR - http://stacks.iop.org/1748-9326/11/i=9/a=094021 IS - 9 ER - TY - JOUR T1 - Is groundwater recharge always serving us well? Water supply provisioning, crop production, and flood attenuation in conflict in Wisconsin, USA JF - Ecosystem Services Y1 - 2016 A1 - Booth, Eric G. A1 - Zipper, Samuel C. A1 - Loheide II, Steven P. A1 - Kucharik, Christopher J. KW - Crop production KW - Flooding KW - Groundwater KW - Hydrologic services KW - Recharge KW - Water supply AB - Ecosystem service mapping can provide an avenue for making effective land management decisions in a holistic way. However, mapped quantities do not always appropriately represent the ecosystem services that are used by humans. We highlight this issue with a case study of groundwater recharge, water supply, flooding, and agricultural production in an urbanizing agricultural watershed in southern Wisconsin, USA. Groundwater recharge is typically treated as a beneficial ecosystem service or service indicator whose value to humans monotonically increases with the amount of recharge. While appropriate from a water supply perspective, this relationship breaks down when excess groundwater recharge leads to flooding and crop damage. We suggest moving beyond groundwater recharge as a stand-alone ecosystem service, and instead propose that observations and biophysical models should be used to quantify the final service humans receive from groundwater (e.g. reliability of water supply from a municipal well). Integration of such derived, point-based metrics with other ecosystem services that are more easily represented at the landscape scale remains a challenge for regional ecosystem service inventories and analyses. VL - 21, Part A SN - 2212-0416 UR - http://www.sciencedirect.com/science/article/pii/S2212041616302315 JO - Ecosystem Services ER - TY - JOUR T1 - Historical foundations and future directions in macrosystems ecology JF - Ecology Letters Y1 - 2016 A1 - Rose, Kevin C. A1 - Graves, Rose A. A1 - Hansen, Winslow D. A1 - Harvey, Brian J. A1 - Qiu, Jiangxiao A1 - Wood, Stephen A. A1 - Ziter, Carly A1 - Turner, Monica G. KW - Hierarchy theory KW - landscape ecology KW - macrosystems ecology KW - space–time KW - spatio-temporal AB - Macrosystems ecology is an effort to understand ecological processes and interactions at the broadest spatial scales and has potential to help solve globally important social and ecological challenges. It is important to understand the intellectual legacies underpinning macrosystems ecology: How the subdiscipline fits within, builds upon, differs from and extends previous theories. We trace the rise of macrosystems ecology with respect to preceding theories and present a new hypothesis that integrates the multiple components of macrosystems theory. The spatio-temporal anthropogenic rescaling (STAR) hypothesis suggests that human activities are altering the scales of ecological processes, resulting in interactions at novel space–time scale combinations that are diverse and predictable. We articulate four predictions about how human actions are “expanding”, “shrinking”, “speeding up” and “slowing down” ecological processes and interactions, and thereby generating new scaling relationships for ecological patterns and processes. We provide examples of these rescaling processes and describe ecological consequences across terrestrial, freshwater and marine ecosystems. Rescaling depends in part on characteristics including connectivity, stability and heterogeneity. Our STAR hypothesis challenges traditional assumptions about how the spatial and temporal scales of processes and interactions operate in different types of ecosystems and provides a lens through which to understand macrosystem-scale environmental change. SN - 1461-0248 UR - http://dx.doi.org/10.1111/ele.12717 ER - TY - JOUR T1 - Invasive species triggers a massive loss of ecosystem services through a trophic cascade JF - Proceedings of the National Academy of Sciences Y1 - 2016 A1 - Walsh, Jake R. A1 - Carpenter, Stephen R. A1 - Vander Zanden, M. Jake AB - Despite growing recognition of the importance of ecosystem services and the economic and ecological harm caused by invasive species, linkages between invasions, changes in ecosystem functioning, and in turn, provisioning of ecosystem services remain poorly documented and poorly understood. We evaluate the economic impacts of an invasion that cascaded through a food web to cause substantial declines in water clarity, a valued ecosystem service. The predatory zooplankton, the spiny water flea (Bythotrephes longimanus), invaded the Laurentian Great Lakes in the 1980s and has subsequently undergone secondary spread to inland lakes, including Lake Mendota (Wisconsin), in 2009. In Lake Mendota, Bythotrephes has reached unparalleled densities compared with in other lakes, decreasing biomass of the grazer Daphnia pulicaria and causing a decline in water clarity of nearly 1 m. Time series modeling revealed that the loss in water clarity, valued at US$140 million (US$640 per household), could be reversed by a 71% reduction in phosphorus loading. A phosphorus reduction of this magnitude is estimated to cost between US$86.5 million and US$163 million (US$430–US$810 per household). Estimates of the economic effects of Great Lakes invasive species may increase considerably if cases of secondary invasions into inland lakes, such as Lake Mendota, are included. Furthermore, such extreme cases of economic damages call for increased investment in the prevention and control of invasive species to better maximize the economic benefits of such programs. Our results highlight the need to more fully incorporate ecosystem services into our analysis of invasive species impacts, management, and public policy. UR - http://www.pnas.org/content/early/2016/03/16/1600366113.abstract ER - TY - JOUR T1 - Urban heat island impacts on plant phenology: intra-urban variability and response to land cover JF - Environmental Research Letters Y1 - 2016 A1 - Samuel C Zipper A1 - Jason Schatz A1 - Aditya Singh A1 - Christopher J Kucharik A1 - Philip A Townsend A1 - Steven P Loheide KW - land surface phenology KW - remote sensing KW - sensor network KW - urban climate KW - urban ecology KW - urban heat island KW - vegetation phenology AB - Despite documented intra-urban heterogeneity in the urban heat island (UHI) effect, little is knownabout spatial or temporal variability in plant response to the UHI. Using an automated temperaturesensor network in conjunction with Landsat-derived remotely sensed estimates of start/end of thegrowing season, we investigate the impacts of the UHI on plant phenology in the city of Madison WI(USA) for the 2012–2014 growing seasons. Median urban growing season length (GSL) estimated fromtemperature sensors is ∼5 d longer than surrounding rural areas, and UHI impacts on GSL arerelatively consistent from year-to-year. Parks within urban areas experience a subdued expression ofGSL lengthening resulting from interactions between the UHI and a park cool island effect. Acrossall growing seasons, impervious cover in the area surrounding each temperature sensor explains >50%of observed variability in phenology. Comparisons between long-term estimates of annual meanphenological timing, derived from remote sensing, and temperature-based estimates of individualgrowing seasons show no relationship at the individual sensor level. The magnitude of disagreementbetween temperature-based and remotely sensed phenology is a function of impervious and grass coversurrounding the sensor, suggesting that realized GSL is controlled by both local land cover andmicrometeorological conditions. VL - 11 SN - 1748-9326 UR - http://stacks.iop.org/1748-9326/11/i=5/a=054023 IS - 5 ER - TY - JOUR T1 - Untangling the effects of shallow groundwater and soil texture as drivers of subfield-scale yield variability JF - Water Resources Research Y1 - 2015 A1 - Zipper, Samuel C. A1 - Soylu, Mehmet Evren A1 - Booth, Eric G. A1 - Loheide, Steven P. KW - 0402 Agricultural systems KW - 0486 Soils/pedology KW - 1813 Eco-hydrology KW - 1829 Groundwater hydrology KW - agroecosystem modeling KW - AgroIBIS-VSF KW - Hydrus-1D KW - Precision agriculture KW - soil-plant-atmosphere continuum KW - water table AB - Water table depth (WTD), soil texture, and growing season weather conditions all play critical roles in determining agricultural yield; however, the interactions among these three variables have never been explored in a systematic way. Using a combination of field observations and biophysical modeling, we answer two questions: (1) under what conditions can a shallow water table provide a groundwater yield subsidy and/or penalty to corn production?; and, (2) how do soil texture and growing season weather conditions influence the relationship between WTD and corn yield? Subfield-scale yield patterns during a dry (2012) and wet (2013) growing season are used to identify sensitivity to weather. Areas of the field that are negatively impacted by wet growing seasons have the shallowest observed WTD (< 1 m), while areas with consistently strong yield have intermediate WTD (1-3 m). Parts of the field that perform consistently poorly are characterized by deep WTD (> 3 m) and coarse soil textures. Modeling results find that beneficial impacts of shallow groundwater are more common than negative impacts under the conditions studied, and that the optimum WTD is shallower in coarser soils. While groundwater yield subsidies have a higher frequency and magnitude in coarse-grained soils, the optimum WTD responds to growing season weather at a relatively constant rate across soil types. We conclude that soil texture defines a baseline upon which WTD and weather interact to determine overall yield. Our work has implications for water resource management, climate/land use change impacts on agricultural production, and precision agriculture. This article is protected by copyright. All rights reserved. SN - 1944-7973 UR - http://dx.doi.org/10.1002/2015WR017522 ER - TY - JOUR T1 - Using evapotranspiration to assess drought sensitivity on a subfield scale with HRMET, a high resolution surface energy balance model JF - Agricultural and Forest Meteorology Y1 - 2014 A1 - Zipper, Samuel C. A1 - Loheide II, Steven P. KW - Drought response KW - Energy balance KW - Evapotranspiration KW - Precision agriculture KW - Spatial heterogeneity KW - Thermal imagery KW - Yield monitoring AB - Abstract Evapotranspiration (ET) rates provide a valuable within-season indicator of plant productivity, as well as data on fluxes of water in a landscape. Applying remote sensing for ET estimation has potential to improve the sustainable management of water resources in agricultural settings. Most current ET models, however, rely on ‘dry’ and ‘wet’ pixels within a given scene to partition turbulent fluxes between latent and sensible heat, thus limiting their ability to map ET throughout the growing season at extremely high (meter scale) spatial resolutions. Here, we develop a field-validated surface energy balance model, High Resolution Mapping of EvapoTranspiration (HRMET), which requires only basic meteorological data, spatial surface temperature and canopy structure data. We use HRMET to estimate ET rates over two commercial cornfields in south-central Wisconsin during the 2012 growing season, which was characterized by severe drought. HRMET results indicate that the magnitude of within-field variability in ET rates was primarily driven by water availability. The application of remotely sensed data to precision agriculture has also been hampered by turnaround time between image acquisition and availability. We introduce relative ET (ETR), which enables comparison of ET rates between image dates by normalizing for variability caused by weather and crop stage. ETR also provides an intuitive, index-like metric for evaluating spatial variability in ET on a subfield scale. ETR maps illuminate persistent patterns in ET across measurement dates that may be driven by soil water availability and topography. ETR is used to develop a novel paired-image technique that can map subfield sensitivity classes to stressors such as drought. Sensitivity class mapping can be used to circumvent issues related to turnaround time to facilitate the incorporation of remotely sensed data into precision agriculture. VL - 197 SN - 0168-1923 UR - http://www.sciencedirect.com/science/article/pii/S0168192314001518 ER -