Data integration is a statistical modeling approach that incorporates multiple data sources within a unified analytical framework. Macrosystems ecology-the study of ecological phenomena at broad scales, including interactions across scales-increasingly employs data integration techniques to expand the spatiotemporal scope of research and inferences, increase the precision of parameter estimates, and account for multiple sources of uncertainty in estimates of multiscale processes. We highlight four common analytical challenges to data integration in macrosystems ecology research: data scale mismatches, unbalanced data, sampling biases, and model development and assessment. We explain each problem, discuss current approaches to address the issue, and describe potential areas of research to overcome these hurdles. Use of data integration techniques has increased rapidly in recent years, and given the inferential value of such approaches, we expect continued development and wider application across ecological disciplines, especially in macrosystems ecology.
Effective conservation requires strategies to monitor populations efficiently, which can be especially difficult for rare or elusive species where field surveys require high effort and considerable cost. Populations of many reptiles, including Sonoran desert tortoises (Gopherus agassizii), are challenging to monitor effectively because they are cryptic, they occur at low densities, and their activity is limited both seasonally and daily. We compared efficiency and statistical power of 2 survey methods appropriate for tortoises and other rare vertebrates, linetransect distance sampling and site occupancy. In 2005 and 2006 combined, we surveyed 120 1-km transects to estimate density and 40 3-ha plots 5 times each to estimate occupancy of Sonoran desert tortoises in 2 mountain ranges in southern Arizona, USA. For both mountain ranges combined, we estimated density to be 0.30 adult tortoises/ha (95% CI 5 0.17-0.43) and occupancy to be 0.72 (95% CI 5 0.56-0.89). For the sampling designs we evaluated, monitoring efforts based on occupancy were 8-36% more efficient than those based on density, when contrasting only survey effort, and 17-30% more efficient when contrasting total effort (surveying, hiking to and from survey locations, and radiotracking). Occupancy had greater statistical power to detect annual declines in the proportion of area occupied than did distance sampling to detect annual declines in density. For example, we estimated that power to detect a 5% annual decline with 10 years of annual sampling was 0.92 (95% CI 5 0.75-0.98) for occupancy and 0.43 (95% CI 5 0.35-0.52) for distance sampling. Although all sampling methods have limitations, occupancy estimation offers a promising alternative for monitoring populations of rare vertebrates, including tortoises in the Sonoran Desert.
Although many species may be vulnerable to changes in climate, forecasting species-level responses can be challenging given the array of physiological, behavioral, and demographic attributes that might be affected. One strategy to improve forecasts is to evaluate how species responded to climatic variation in the past. We used 22 years of capture-recapture data for Sonoran desert tortoises (Gopherus morafkai) collected from 15 locations across their geographic range in Arizona to evaluate how environmental factors affected spatial and temporal variation in survival. Although rates of annual survival were generally high ([Formula: see text] = 0.92), survival of adults decreased with drought severity, especially in portions of their range that were most arid and nearest to cities. In three locations where large numbers of carcasses from marked tortoises were recovered, survival of adults was markedly lower during periods of severe drought ([Formula: see text] = 0.77-0.81) compared to all other periods ([Formula: see text] = 0.93-0.98). Assuming continued levels of dependency of humans on fossil fuels, survival of adult tortoises is predicted to decrease by an average of 3 % during 2035-2060 relative to survival during 1987-2008 in 14 of the 15 populations we studied. This decrease could reduce persistence of tortoise populations, especially in arid portions of their range. Temporal and spatial variation in drought conditions are important determinants of survival in adult desert tortoises.
The postdoctoral workforce comprises a growing proportion of the STEM community and plays a vital role in advancing science. Postdoc professional development, however, remains rooted in outdated realities. We propose enhancements to postdoc-centred policies and practices to better align this career stage with contemporary job markets and work life. By facilitating productivity, wellness, and career advancement, the proposed changes will benefit all stakeholders in postdoc success -including research teams, institutions, professional societies, and the scientific community as a whole. To catalyse reform, we outline recommendations for a) skills-based training tailored to the current career landscape, and b) supportive policies and tools outlined in postdoc handbooks. We also invite the ecology and evolution community to lead further progressive reform. Main Text (current word count 2188):Postdoctoral researchers ("postdocs"; Fig. 1A) contribute extensive research, teaching, and service to their supervising faculty, home institutions, and broader scientific communities [1][2][3][4] . In principle, these contributions are rewarded with opportunities to specialize and develop independence. In practice, however, postdocs' progress and well-being are constrained by social, mental, and financial challenges 1,5-7 . Further, the skills and credentials that are prioritized in postdoc positions are misaligned with contemporary job markets (e.g. [8][9][10][11] , Figure 1C). These issues highlight an urgent need for policies and practices that better support a growing postdoctoral workforce. Ultimately, this will benefit all stakeholders in postdoc success --providing ethical and far-reaching returns on time and resource investments [1][2][3][4][5]12 .Below, we describe five goals for enhancing postdoc professional development. We also highlight innovative examples of policies and practices from around the globe. Our recommendations are applicable to many STEM disciplines, but especially relevant to ecology and evolution. Alternative careers in these fields commonly require additional training [13][14][15] , and non-academic paths are often unknown to both postdocs and their mentors. This causes anxiety and reticence for postdocs who, by choice or by necessity, are considering nontraditional careers 1,16,17 . Fortunately, the ecology and evolution community is also poised to lead adaptive reform. Our research targets complex interactions spanning many levels of biological organization. Consequently, our community possesses the tools and perspectives needed for strategic, evidence-based engineering of workplace ecosystems 9 .Goal 1: Align career development with job markets 1,3,38,39 ). More effective mentorship can be facilitated through training, 36 and should be incentivized during hiring, evaluation, and merit-based promotion 40 .
Understanding how natural and anthropogenic processes affect population dynamics of species with patchy distributions is critical to predicting their responses to environmental changes. Despite considerable evidence that demographic rates and dispersal patterns vary temporally in response to an array of biotic and abiotic processes, few applications of metapopulation theory have sought to explore factors that explain spatiotemporal variation in extinction or colonization rates. To facilitate exploring these factors, we extended a spatially explicit model of metapopulation dynamics to create a framework that requires only binary presence–absence data, makes few assumptions about the dispersal process, and accounts for imperfect detection. We apply this framework to 22 yr of biannual survey data for lowland leopard frogs, Lithobates yavapaiensis, an amphibian that inhabits arid stream systems in the southwestern United States and northern Mexico. Our results highlight the importance of accounting for factors that govern temporal variation in transition probabilities, as both extinction and colonization rates varied with hydrologic conditions. Specifically, local extinctions were more frequent during drought periods, particularly at sites without reliable surface water. Colonization rates increased when larval and dispersal periods were wetter than normal, which increased the probability that potential emigrants metamorphosed and reached neighboring sites. Extirpation of frogs from all sites in one watershed during a period of severe drought demonstrated the influence of site‐level features, as frogs persisted only in areas where most sites held water consistently and where the amount of sediment deposited from high‐elevation wildfires was low. Application of our model provided novel insights into how climate‐related processes affected the distribution and population dynamics of an arid‐land amphibian. The approach we describe has application to a wide array of species that inhabit patchy environments, can improve our understanding of factors that govern metapopulation dynamics, and can inform strategies for conservation of imperiled species.
Dynamics of many amphibian populations are governed by the distribution and availability of water. Therefore, understanding the hydrological mechanisms that explain spatial and temporal variation in occupancy and abundance will improve our ability to conserve and recover populations of vulnerable amphibians. We used 16 years of survey data from intermittent mountain streams in the Sonoran Desert to evaluate how availability of surface water affected survival and adult recruitment of a threatened amphibian, the lowland leopard frog (Lithobates yavapaiensis). Across the entire study period, monthly survival of adults ranged from 0.72 to 0.99 during summer and 0.59 to 0.94 during winter and increased with availability of surface water (Z = 7.66; P < 0.01). Recruitment of frogs into the adult age class occurred primarily during winter and ranged from 1.9 to 3.8 individuals/season/pool; like survival, recruitment increased with availability of surface water (Z = 3.67; P < 0.01). Although abundance of frogs varied across seasons and years, we found no evidence of a systematic trend during the 16-year study period. Given the strong influence of surface water on population dynamics of leopard frogs, conservation of many riparian obligates in this and similar arid regions likely depends critically on minimizing threats to structures and ecosystem processes that maintain surface waters. Understanding the influence of surface-water availability on riparian organisms is particularly important because climate change is likely to decrease precipitation and increase ambient temperatures in desert riparian systems, both of which have the potential to alter fundamentally the hydrology of these systems.
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