Climate, physical landscapes, and biota interact to generate heterogeneous hydrologic conditions in space and over time, which are reflected in spatial patterns of species distributions. As these species distributions respond to rapid climate change, microrefugia may support local species persistence in the face of deteriorating climatic suitability. Recent focus on temperature as a determinant of microrefugia insufficiently accounts for the importance of hydrologic processes and changing water availability with changing climate. Where water scarcity is a major limitation now or under future climates, hydrologic microrefugia are likely to prove essential for species persistence, particularly for sessile species and plants. Zones of high relative water availability - mesic microenvironments - are generated by a wide array of hydrologic processes, and may be loosely coupled to climatic processes and therefore buffered from climate change. Here, we review the mechanisms that generate mesic microenvironments and their likely robustness in the face of climate change. We argue that mesic microenvironments will act as species-specific refugia only if the nature and space/time variability in water availability are compatible with the ecological requirements of a target species. We illustrate this argument with case studies drawn from California oak woodland ecosystems. We posit that identification of hydrologic refugia could form a cornerstone of climate-cognizant conservation strategies, but that this would require improved understanding of climate change effects on key hydrologic processes, including frequently cryptic processes such as groundwater flow.

Anticipating species movement under climate change is a major focus in conservation. Bioclimate models are one of the few predictive tools for adaptation planning, but are limited in accounting for (i) climatic tolerances in preadult life stages that are potentially more vulnerable to warming; and (ii) local‐scale movement and use of climatic refugia as an alternative or complement to large‐scale changes in distribution. To assess whether these shortfalls can be addressed with field demographic data, we used California valley oak (Quercus lobata Nee), a long‐lived species with juvenile life stages known to be sensitive to climate. We hypothesized that the valley oak bioclimate model, based on adults, would overpredict the species' ability to remain in the projected persisting area, due to higher climate vulnerability of young life stages; and underpredict the potential for the species to remain in the projected contracting area in local‐scale refugia. We assessed the bioclimate model projections against actual demographic patterns in natural populations. We found that saplings were more constricted around surface water than adults in the projected contracting area. We also found that the climate envelope for saplings is narrower than that for adults. Saplings disappeared at a summer maximum temperature 3 °C below that associated with adults. Our findings indicate that rather than a complete shift northward and upward, as predicted by the species bioclimate model, valley oaks are more likely to experience constriction around water bodies, and eventual disappearance from areas exceeding a threshold of maximum temperature. Ours is the first study we know of to examine the importance of discrete life stage climate sensitivities in determining bioclimate modeling inputs, and to identify current climate change‐related constriction of a species around microrefugia. Our findings illustrate that targeted biological fieldwork can be central to understanding climate change‐related movement for long‐lived, sessile species.

Despite the appeal of the iso/anisohydric framework for classifying plant drought responses, recent studies have shown that such classifications can be strongly affected by a plant's environment. Here, we present measured in situ drought responses to demonstrate that apparent isohydricity can be conflated with environmental conditions that vary over space and time. In particular, we (a) use data from an oak species (Quercus douglasii) during the 2012–2015 extreme drought in California to demonstrate how temporal and spatial variability in the environment can influence plant water potential dynamics, masking the role of traits; (b) explain how these environmental variations might arise from climatic, topographic, and edaphic variability; (c) illustrate, through a “common garden” thought experiment, how existing trait‐based or response‐based isohydricity metrics can be confounded by these environmental variations, leading to Type‐1 (false positive) and Type‐2 (false negative) errors; and (d) advocate for the use of model‐based approaches for formulating alternate classification schemes. Building on recent insights from greenhouse and vineyard studies, we offer additional evidence across multiple field sites to demonstrate the importance of spatial and temporal drivers of plants' apparent isohydricity. This evidence challenges the use of isohydricity indices, per se, to characterize plant water relations at the global scale.

The study of food systems is a quickly growing field. In high demand by postsecondary students, new food systems studies programs are emerging from a range of disciplines. Food systems are inherently complex and are best understood from a range of academic perspectives and practical contexts. We review current scholarship on food systems pedagogy and present approaches for developing and implementing food systems curricula. A literature review and our experience indicate that effective food systems program approaches include emphasizing interdisciplinarity and a systems approach and balancing experience, theory, and practical skills acquisition. We discuss strategies, challenges and opportunities for building food systems curricula.

Natural springs in water‐limited landscapes are biodiversity hotspots and keystone ecosystems that have a disproportionate influence on surrounding landscapes despite their usually small size. Some springs served as evolutionary refugia during previous climate drying, supporting relict species in isolated habitats. Understanding whether springs will provide hydrologic refugia from future climate change is important to biodiversity conservation but is complicated by hydrologic variability among springs, data limitations, and multiple non‐climate threats to groundwater‐dependent ecosystems. We present a conceptual framework for categorizing springs as potentially stable, relative, or transient hydrologic refugia in a drying climate. Clues about the refugial capacity of springs can be assembled from various approaches, including citizen‐science‐powered ecohydrologic monitoring, remote sensing, landowner interviews, and environmental tracer analysis. Managers can integrate multiple lines of evidence to predict which springs may become future refugia for species of concern, strengthening the long‐term effectiveness of their conservation and restoration, and informing climate adaptation for terrestrial and freshwater species.