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Climate change and coastal wetland salinization: Physiological and ecological consequences for Arctic waterfowl

Coastal wetland salinization related to warming climate has the potential to impact ecological systems globally. In Alaska, the Yukon-Kuskokwim Delta (YKD) supports large concentrations of breeding water birds and is an ecologically important area for conservation of migratory bird biodiversity. On the YKD, the majority of waterfowl nest in low elevation coastal tundra where storm surges drive saline water into terrestrial wetland habitats. Because newly hatched water birds lack functional salt glands to process saline water, salinization may negatively impact their growth and survival. We investigated potential demographic impacts of wetland salinization by conducting controlled physiological experiments to determine consequences of saline water exposure to spectacled Somateria fischeri and Steller's eider Polysticta stelleri ducklings, and analysed habitat suitability based on experimentally defined tolerance thresholds and sampled wetland salinity levels. We found physiological and behavioural pathologies in <1 week old ducklings at exposure levels of 6 parts per thousand (ppt), and found some evidence of reduced growth in ducklings first exposed after 1 week of age. We conclude that the acute toxicity threshold for ducklings <1 week of age is ≤6 ppt. We found that the area of coastal tundra where wetland salinity exceeded 6 ppt varied considerably among years, suggesting that some portion of the breeding range is unsuitable for rearing ducklings in some years. However, we also found that most eiders in most years nested in areas with salinity at or exceeding the tolerance threshold for ducklings, suggesting that nesting eiders do not appear to avoid saline habitats. We suggest that localized fresh water refugia currently may allow resilience to salinization during the critical period. Understanding how species and habitats respond to climate driven changes is essential for predicting future patterns of distribution and abundance, and is necessary for making informed decisions about conservation priorities. Our study provides insights into the extent of wetland salinization in Alaska, mechanism of impact and current ecological consequences on avian communities depending on these habitats. With ongoing climate change, the probability of species crossing physiological tolerance thresholds of wetland salinity may change in the future.

Functional Ecology

Time series of suspended-solids concentration, salinity, temperature, and total mercury concentration in San Francisco Bay during water year 1998

Many physical processes affect how constituents within San Francisco Bay vary. Processes and their associated time scales include turbulence (seconds), semidiurnal and diurnal tides (hours), the spring-neap tidal cycle (days), freshwater flow (weeks), seasonal winds (months), ecological and climatic changes (years), and geologic changes (thousands of years). Continuous time series of data on basic state variables of the bay, such as suspended-solids concentration (SSC), salinity, and water temperature, provide insight on the effect and relative importance of physical processes on the bay. SSC time series and Regional Monitoring Program (RMP) water-quality data can be used to calculate time series of some traceelement concentrations (Schoellhamer, 1997a, 1997b). The purpose of this chapter is to describe qualitatively time series of SSC, salinity, water temperature, and mercury during water year 1998 (October 1997 through September 1998). Salinity, temperature, and sediment are important components of the San Francisco Bay estuarine system. Salinity and temperature affect the hydrodynamics (Monismith et al., 1996; Schoellhamer and Burau, 1998), geochemistry (Kuwabara et al., 1989), and ecology (Cloern, 1984; Nichols et al., 1986; Jassby et al., 1995) of the bay. Suspended sediments limit light availability in the bay, which, in turn, limits primary production (Cloern, 1987; Cole and Cloern, 1987), and thus food for higher trophic levels. Sediments deposit in ports and shipping channels, which must be dredged to maintain navigation (U.S. Environmental Protection Agency, 1992). Potentially toxic substances, such as metals and pesticides, adsorb to sediment particles (Kuwabara et al., 1989; Domagalski and Kuivila, 1993; Flegal et al., 1996; Schoellhamer, 1997a, 1997b). The transport and fate of suspended sediments are important factors in determining the transport and fate of constituents adsorbed on the sediments. For example, the concentration of suspended particulate chromium in the bay appears to be controlled primarily by sediment resuspension (Abu-Saba and Flegal, 1995). Concentrations of dissolved trace elements are greater in South Bay than elsewhere in San Francisco Bay, and bottom sediments are believed to be a significant source (Flegal et al., 1991). The sediments on the bay bottom provide habitat for benthic communities that can ingest these substances and introduce them into the food web (Luoma et al., 1985; Brown and Luoma, 1995, Luoma 1996). Bottom sediments also are a reservoir of nutrients that contribute to the maintenance of estuarine productivity (Hammond et al., 1985).

California

Key ecological responses to nitrogen are altered by climate change

Climate change and anthropogenic nitrogen deposition are both important ecological threats. Evaluating their cumulative effects provides a more holistic view of ecosystem vulnerability to human activities, which would better inform policy decisions aimed to protect the sustainability of ecosystems. Our knowledge of the cumulative effects of these stressors is growing, but we lack an integrated understanding. In this Review, we describe how climate change alters key processes in terrestrial and freshwater ecosystems related to nitrogen cycling and availability, and the response of ecosystems to nitrogen addition in terms of carbon cycling, acidification and biodiversity.

Nature Climate Change

Estimating heterotrophic respiration at large scales: Challenges, approaches, and next steps

Heterotrophic respiration (HR), the aerobic and anaerobic processes mineralizing organic matter, is a key carbon flux but one impossible to measure at scales significantly larger than small experimental plots. This impedes our ability to understand carbon and nutrient cycles, benchmark models, or reliably upscale point measurements. Given that a new generation of highly mechanistic, genomic-specific global models is not imminent, we suggest that a useful step to improve this situation would be the development of “Decomposition Functional Types” (DFTs). Analogous to plant functional types (PFTs), DFTs would abstract and capture important differences in HR metabolism and flux dynamics, allowing modelers and experimentalists to efficiently group and vary these characteristics across space and time. We argue that DFTs should be initially informed by top-down expert opinion, but ultimately developed using bottom-up, data-driven analyses, and provide specific examples of potential dependent and independent variables that could be used. We present an example clustering analysis to show how annual HR can be broken into distinct groups associated with global variability in biotic and abiotic factors, and demonstrate that these groups are distinct from (but complementary to) already-existing PFTs. A similar analysis incorporating observational data could form the basis for future DFTs. Finally, we suggest next steps and critical priorities: collection and synthesis of existing data; more in-depth analyses combining open data with rigorous testing of analytical results; using point measurements and realistic forcing variables to constrain process-based models; and planning by the global modeling community for decoupling decomposition from fixed site data. These are all critical steps to build a foundation for DFTs in global models, thus providing the ecological and climate change communities with robust, scalable estimates of HR.

Ecosphere

Minimal shift of eastern wild turkey nesting phenology associated with projected climate change

Climate change may induce mismatches between wildlife reproductive phenology and temporal occurrence of resources necessary for reproductive success. Verifying and elucidating the causal mechanisms behind potential mismatches requires large-scale, longer-duration data. We used eastern wild turkey ( Meleagris gallopavo silvestris ) nesting data collected across the southeastern U.S. over eight years to investigate potential climatic drivers of variation in nest initiation dates. We investigated climactic relationships with two datasets, one inclusive of successful and unsuccessful nests (full dataset) and another of just successful nests (successfully hatched dataset), to determine whether successfully hatched nests responded differently to weather changes than all nests did. In the full dataset, each 10 cm increase in January precipitation was associated with nesting occurring 0.46-0.66 days earlier, and each 10 cm increase in precipitation during the 30 days preceding nesting was associated with nesting occurring 0.17-0.21 days later. In the successfully hatched dataset, a 10 cm increase in March precipitation was associated with nesting occurring 0.67-0.74 days earlier, and an increase of one unit of variation in February maximum temperature was associated with nesting occurring 0.02 days later. We combined the results of these modeled relationships with multiple climate scenarios to understand potential implications of future climate change on wild turkey nesting phenology; results indicated that mean nest initiation date is projected to change by <0.1 day by 2040-2060. Wild turkey nesting phenology did not track changes in spring green-up timing, which could result in phenological mismatch between the timing of nesting and the availability of resources critical for successful reproduction.

Climate Change Ecology

Contrasting demographic responses under future climate for two populations of a montane amphibian

For species with complex life histories, climate change can have contrasting effects for different life stages within locally adapted populations and may result in responses counter to general climate change predictions. Using data from two, 14-year demographic studies for a North American montane amphibian, Cascades frog ( Rana cascadae ), we quantified how aspects of current climate influenced annual survival of larvae and adult stages and modeled the stochastic population growth rate (λ s ) of each population for current (1980–2006) and future periods (2080s). Climate drivers of survival for the populations were similar for larvae (i.e., decreases in precipitation lead to pond drying and mortality), but diverged for terrestrial stages where decreases in winter length and summer precipitation had opposite effects. By the 2080s, we predict one population will be in sharp decline (λ s = 0.90), while the other population will remain nearly stable (λ s = 0.99) in the absence of other stressors, such as mortality due to disease. Our case study demonstrates a result counter to many climate envelope predictions in that stage-specific responses to local climate and hydrology result in a higher extinction risk for the more northern population.

California, Oregon, Washington

Modeling current and future distribution of invasive tegu lizards along geopolitical boundaries in the contiguous United States: Implications for invasion threat

Historically, constrained temperature ranges limited the spread of invasive herpetofauna into temperate climates, but climate change is predicted to facilitate broader distributions. There are three species of tegu lizards native to South America and available in the pet trade that have a high risk of invasion and deleterious impacts to native ecosystems in the United States (US). There are four populations of the black and white tegu ( Salvator merianae ) in Florida and sightings as far north as North Carolina and west as California. Red tegus ( S. rufescens ) have been observed in Florida, and there is an established population of gold tegus ( Tupinambis teguixin ) in Florida. We updated previous distribution models for the contiguous United States (CONUS) that used occurrence points from their native range in South America to evaluate potential changes given current and future climate scenarios (+2 °C and +4 °C warming). Under current climate conditions, one or more tegu species have the potential to occupy most ecoregions in the CONUS. Under a + 4 °C warming scenario, suitable habitat increases by 11 % for S. merianae , 31 % for S. rufescens . The proportion of suitable habitat for T. teguixin was small under all scenarios, but increased from 0.0003 to 0.0017. For S. merianae , parts of Florida become less suitable, while suitability increases in this region for the other two species. Additionally, much of the western US is projected to be suitable for S. rufescens . Our case study underscores the potential for climate change to compound invasion threats that could outpace effective managerial responses.

contiguous United States

Climatological effects on survival, recruitment, and possible extirpation of a Sierra Nevada anuran

The drivers of population dynamics are a primary interest of ecologists, and predicting the consequences of climate variability on wildlife populations benefits from an understanding of how weather causes variation in the vital rates of populations. Given recent and projected extremes in annual precipitation in the Sierra Nevada of California, USA, including two severe droughts, we sought to examine the role of snowpack and summer water availability on the population dynamics and potential extirpation of a meadow population of the U.S. Endangered Sierra Nevada yellow-legged frog ( Rana sierrae ) using a long-term capture-mark-recapture dataset. We found that snowpack and summer water availability affected both survival and recruitment probabilities. Although these variables only explained approximately 17 % of the annual variation in adult survival, they explained 81 % of the variation in recruitment into the adult population. Following two severe, extended droughts and a nearby wildfire, the population consisted of 20 or fewer individuals with >95 % certainty, and 10 or fewer individuals with 64 % certainty. If realized, increased precipitation volatility and extended droughts likely present an additional threat to some meadow populations of this endangered frog.

California

Global groundwater solute composition and concentrations

Informed analysis of policies related to food security, global climate change, wetland ecology, environmental nutrient flux, element cycling, groundwater weathering, continental denudation, human health, etc. depends to a large extent on quantitative estimates of solute mass fluxes into and out of all global element pools including the enigmatic global aquifer systems. Herein for the first time, we proffer the mean global solute concentration of all major and selected minor and trace solutes in the active groundwater that represents 99% of liquid fresh water on Earth. Concentrations in this significant element pool have yielded to a geospatial machine learning kNN-nearest neighbors’ algorithm with numerous geospatial predictors utilizing a large new lithology/climate/aquifer age/elevation based solute database. The predicted concentrations are consistent with traditional solute ratios, concentrations, and thermodynamic saturation indices.

Groundwater

Time series Of suspended-solids concentration, salinity, temperature, and total mercury concentration in San Francisco Bay during water year 1996

Many physical processes affect how constituents within San Francisco Bay vary. Processes and their associated time scales include turbulence (seconds), semidiurnal and diurnal tides (hours), the spring-neap tidal cycle (days), freshwater flow (weeks), seasonal winds (months), ecological and climatic changes (years), and geologic changes (thousands of years). The effect and relative importance of physical processes on the Bay can be determined from continuous time series of suspended-solids concentration (SSC), salinity, and water temperature. SSC time series and Regional Monitoring Program (RMP) waterquality data can be used to calculate time series of some trace-element concentrations (Schoellhamer, 1997). The purpose of this chapter is to qualitatively describe time series of SSC, salinity, water temperature, and mercury during water year 1996 (October 1995 through September 1996). In addition, a calculated time series of mercury will be used to evaluate the accuracy of using instantaneous water samples to evaluate a 4-day average water-quality objective.

California

Ecological and management implications of climate change induced shifts in phenology of coastal fish and wildlife species in the Northeast CASC region

Climate change is causing species to shift their phenology, or the timing of recurring life events such as migration and reproduction, in variable and complex ways. This can potentially result in mismatches or asynchronies in food and habitat resources that negatively impact individual fitness, population dynamics, and ecosystem function. Numerous studies have evaluated phenological shifts in terrestrial species, particularly birds and plants, yet far fewer evaluations have been conducted for marine animals. This project seeks to improve our understanding of shifts in the timing of seasonal migration, spawning or breeding, and biological development (i.e. life stages present, dominant) of coastal fishes, marine mammals,and migratory shore and seabirds along the U.S Atlantic coast. Ideally the suite of species selected will allow us to compare whether fish, marine mammals, shore and seabird predators are shifting their phenology at different rates than their primary prey and optimal habitat conditions, thus influencing trophic interactions and population dynamics. A comprehensive literature review will be conducted simultaneous to data collection and synthesis to determine what is known, and what knowledge/information/data gaps exist regarding regional phenological responses of coastal species to climate change. Project results will help managers assess the vulnerability of coastal species to climate change by providing information on how they are responding to impacts in the region.

Conference Paper

Declining ecological resilience and invasion resistance under climate change in the sagebrush region, United States

In water-limited dryland ecosystems of the Western United States, climate change is intensifying the impacts of heat, drought, and wildfire. Disturbances often lead to increased abundance of invasive species, in part, because dryland restoration and rehabilitation are inhibited by limited moisture and infrequent plant recruitment events. Information on ecological resilience to disturbance (recovery potential) and resistance to invasive species can aid in addressing these challenges by informing long-term restoration and conservation planning. Here, we quantified the impacts of projected future climate on ecological resilience and invasion resistance (R&R) in the sagebrush region using novel algorithms based on ecologically relevant and climate-sensitive predictors of climate and ecological drought. We used a process-based ecohydrological model to project these predictor variables and resulting R&R indicators for two future climate scenarios and 20 climate models. Results suggested widespread future R&R decreases (24%–34% of the 1.16 million km 2 study area) that are generally consistent among climate models. Variables related to rising temperatures were most strongly linked to decreases in R&R indicators. New continuous R&R indices quantified responses to climate change; particularly useful for areas without projected change in the R&R category but where R&R still may decrease, for example, some of the areas with a historically low R&R category. Additionally, we found that areas currently characterized as having high sagebrush ecological integrity had the largest areal percentage with expected declines in R&R in the future, suggesting continuing declines in sagebrush ecosystems. One limitation of these R&R projections was relatively novel future climatic conditions in particularly hot and dry areas that were underrepresented in the training data. Including more data from these areas in future updates could further improve the reliability of the projections. Overall, these projected future declines in R&R highlight a growing challenge for natural resource managers in the region, and the resulting spatially explicit datasets provide information that can improve long-term risk assessments, prioritizations, and climate adaptation efforts.

western United States

Responding to ecological transformation in Capitol Reef National Park, Utah—Employee perspectives from pilot interviews from the Cross-Park Resist-Assist-Direct Project

Executive Summary Climate change is causing a range of changes that can affect the natural, cultural, and built resources of the Nation’s protected areas and affect opportunities to visit and recreate in these spaces. Changes in temperature and precipitation patterns also affect species and habitats, leading to ecological transformation. This report describes findings from pilot research conducted in Capitol Reef National Park, Utah (hereinafter referred to as “Capitol Reef” or “the Park”) as part of a larger interagency study of how National Park Service (NPS) staff are considering management of transforming ecosystems. Semi-structured interviews were used to assess how Capitol Reef employees (n=9) understand the challenge of ecological transformation, including their perceptions of how climate change is affecting the Park’s natural and cultural resources, the multiple timeframes over which employees respond to climate change impacts, and their awareness and understanding of ecological transformation and the Resist-Accept-Direct (RAD) framework, which was developed to address ecological transformation, that is, ecosystems changing in response to changes in climate conditions (Schuurman and others, 2020, 2022). The interviews also solicited employee perceptions about constraints and enabling factors that allow Capitol Reef to effectively respond to ecological transformation. The report uses a conceptual framework that has been used by the National Park Service Climate Change Response Program (Clifford and others, 2022) to structure the reporting of the data about constraints and enabling factors, with sections describing the role of factors internal to an individual employee (culture, worldviews, and understanding of an ecological system) and contextual factors external to an individual (institutional context, social feasibility and scientific uncertainty as influenced by available scientific information). Participating Capitol Reef staff perceived the most pressing climate impacts in the Park as increasing air temperatures, aridity, and flash floods, which are impacting natural and cultural resources, public safety, and infrastructure. Staff mostly agreed on what the future landscape (approximately 50 years into the future) may look like at Capitol Reef in terms of changes in vegetation and future temperature and precipitation conditions. However, staff had more divergent views or were uncertain about how specific species will adapt to future conditions (for example, how endemic plants might shift their ranges) and are grappling with which management strategies to take at which times. Staff also had differing opinions about how much data is needed to prompt action. Interviewees agreed that leadership in the Park had made climate change a priority and created a climate-attuned culture among staff. Participating employees described the park culture at Capitol Reef as collaborative, with frequent communication and work across divisions, which, as an example, shapes responses to flash floods and other events (for example, working across divisions on search and rescue, or repairing fencing that is washed out by storms). This collaborative, climate-attuned culture may help Capitol Reef in future problem-solving as it grapples with how to respond to climate change and ecological transformation in the Park.

Utah

Editorial: Plant phenology shifts and their ecological and climatic consequences

Climate change is causing plant phenology to shift, with consequences for ecosystems and the Earth’s climate. Over the last decades, the timing of many important phenological events has advanced in spring, such as leaf emergence and flowering, or been delayed in fall, such as leaf coloration and leaf fall. The consequences of such phenological shifts are still largely unknown, but are hypothesized to have cascading effects on ecosystems, carbon and water cycles, and Earths’ climate. With this research topic, we aimed to synthesize and inspire innovative research in plant phenology to address research questions and challenges on the consequences of phenological shifts on ecosystem function and local hydrology. The articles presented here improve our understanding of the physiological mechanisms responsible for the current phenological changes in spring and fall and provide insight into some of the consequences of these changes on hydrological cycles and ecosystem functioning.

Frontiers in Plant Science

Climate change-induced vegetation shifts lead to more ecological droughts despite projected rainfall increases in many global temperate drylands

Drylands occur world-wide and are particularly vulnerable to climate change since dryland ecosystems depend directly on soil water availability that may become increasingly limited as temperatures rise. Climate change will both directly impact soil water availability, and also change plant biomass, with resulting indirect feedbacks on soil moisture. Thus, the net impact of direct and indirect climate change effects on soil moisture requires better understanding. We used the ecohydrological simulation model SOILWAT at sites from temperate dryland ecosystems around the globe to disentangle the contributions of direct climate change effects and of additional indirect, climate change-induced changes in vegetation on soil water availability. We simulated current and future climate conditions projected by 16 GCMs under RCP 4.5 and RCP 8.5 for the end of the century. We determined shifts in water availability due to climate change alone and due to combined changes of climate and the growth form and biomass of vegetation. Vegetation change will mostly exacerbate low soil water availability in regions already expected to suffer from negative direct impacts of climate change (with the two RCP scenarios giving us qualitatively similar effects). By contrast, in regions that will likely experience increased water availability due to climate change alone, vegetation changes will counteract these increases due to increased water losses by interception. In only a small minority of locations, climate change induced vegetation changes may lead to a net increase in water availability. These results suggest that changes in vegetation in response to climate change may exacerbate drought conditions and may dampen the effects of increased precipitation, i.e. leading to more ecological droughts despite higher precipitation in some regions. Our results underscore the value of considering indirect effects of climate change on vegetation when assessing future soil moisture conditions in water-limited ecosystems.

Global Change Biology

Linear and nonlinear effects of temperature and precipitation on ecosystem properties in tidal saline wetlands

Climate greatly influences the structure and functioning of tidal saline wetland ecosystems. However, there is a need to better quantify the effects of climatic drivers on ecosystem properties, particularly near climate-sensitive ecological transition zones. Here, we used climate- and literature-derived ecological data from tidal saline wetlands to test hypotheses regarding the influence of climatic drivers (i.e., temperature and precipitation regimes) on the following six ecosystem properties: canopy height, biomass, productivity, decomposition, soil carbon density, and soil carbon accumulation. Our analyses quantify and elucidate linear and nonlinear effects of climatic drivers. We quantified positive linear relationships between temperature and above-ground productivity and strong positive nonlinear (sigmoidal) relationships between (1) temperature and above-ground biomass and canopy height and (2) precipitation and canopy height. Near temperature-controlled mangrove range limits, small changes in temperature are expected to trigger comparatively large changes in biomass and canopy height, as mangrove forests grow, expand, and, in some cases, replace salt marshes. However, within these same transition zones, temperature-induced changes in productivity are expected to be comparatively small. Interestingly, despite the significant above-ground height, biomass, and productivity relationships across the tropical–temperate mangrove–marsh transition zone, the relationships between temperature and soil carbon density or soil carbon accumulation were not significant. Our literature review identifies several ecosystem properties and many regions of the world for which there are insufficient data to fully evaluate the influence of climatic drivers, and the identified data gaps can be used by scientists to guide future research. Our analyses indicate that near precipitation-controlled transition zones, small changes in precipitation are expected to trigger comparatively large changes in canopy height. However, there are scant data to evaluate the influence of precipitation on other ecosystem properties. There is a need for more decomposition data across climatic gradients, and to advance understanding of the influence of changes in precipitation and freshwater availability, additional ecological data are needed from tidal saline wetlands in arid climates. Collectively, our results can help scientists and managers better anticipate the linear and nonlinear ecological consequences of climate change for coastal wetlands.

Ecosphere

Climate change and disturbance interactions: Workshop on climate change and disturbance interactions in western North America, Tucson, Ariz., 12-15 February 2007

Warming temperatures across western North America, coupled with increased drought, are expected to exacerbate disturbance regimes, particularly wildfires, insect outbreaks, and invasions of exotic species. Many ecologists and resource managers expect ecosystems to change more rapidly from disturbance effects than from the effects of a changing climate by itself. A particular challenge is to understand the interactions among disturbance regimes; for example, how will massive outbreaks of bark beetles, which kill drought-stressed trees by feeding on cambial tissues, increase the potential for large severe wildfires in a warming climate? Researchers in climatology, ecosystem science, fire and insect ecology, and landscape modeling from across western North America convened in Tucson, Ariz., for a 2 and a half day intensive workshop to identify new research directions in climate change and disturbance ecology. Four work groups focused on different aspects of the response of disturbance regimes to climate change: (1) extreme events and climatic variability (2) the effects of changing disturbance regimes on ecosystems, (3) disturbance interactions and cumulative effects, and (4) developing new landscape disturbance models. The workshop was structured with the analytic hierarchy process, a decision support method for achieving consensus from diverse groups of experts without sacrificing individual contributions.

Eos, Earth and Space Science News

A Bayesian approach for temporally scaling climate for modeling ecological systems

With climate change becoming more of concern, many ecologists are including climate variables in their system and statistical models. The Standardized Precipitation Evapotranspiration Index (SPEI) is a drought index that has potential advantages in modeling ecological response variables, including a flexible computation of the index over different timescales. However, little development has been made in terms of the choice of timescale for SPEI. We developed a Bayesian modeling approach for estimating the timescale for SPEI and demonstrated its use in modeling wetland hydrologic dynamics in two different eras (i.e., historical [pre-1970] and contemporary [post-2003]). Our goal was to determine whether differences in climate between the two eras could explain changes in the amount of water in wetlands. Our results showed that wetland water surface areas tended to be larger in wetter conditions, but also changed less in response to climate fluctuations in the contemporary era. We also found that the average timescale parameter was greater in the historical period, compared with the contemporary period. We were not able to determine whether this shift in timescale was due to a change in the timing of wet&ndash;dry periods or whether it was due to changes in the way wetlands responded to climate. Our results suggest that perhaps some interaction between climate and hydrologic response may be at work, and further analysis is needed to determine which has a stronger influence. Despite this, we suggest that our modeling approach enabled us to estimate the relevant timescale for SPEI and make inferences from those estimates. Likewise, our approach provides a mechanism for using prior information with future data to assess whether these patterns may continue over time. We suggest that ecologists consider using temporally scalable climate indices in conjunction with Bayesian analysis for assessing the role of climate in ecological systems.

Ecology and Evolution