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Details can be found in the following manuscript. Contact author Brooks for further inquiries. Brooks, J. M., Baxter, C. V., Warren, D. R., & MacNeill, K. L. (2025). Enter the Mosaic: Aquatic‐Terrestrial Reciprocal Fluxes and Food Webs Are Dynamically Interdependent Across Space and Through Time. Freshwater Biology, 70(9), e70094. 

ABSTRACT Decades‐old research describes dynamic interdependence among aquatic and terrestrial food webs, leading to calls for integrating cross‐ecosystem linkages with landscape ecology to evaluate dynamics of spatially‐subsidised food webs. Though development of meta‐community theory has suggested that such spatial dynamics may help sustain biodiversity, empirical data remain limited. In northern Yellowstone National Park, over a century of terrestrial wildlife dynamics, including the extirpation and subsequent reintroduction of wolves, have contributed to a habitat mosaic in which stream‐riparian ecosystems are dominated by either woody or herbaceous vegetation. In the context of this habitat mosaic, we addressed the overarching questions: (1) Are habitat mosaics associated with spatial and temporal variation in reciprocal fluxes and linked food webs and (2) how do biodiversity, organism traits and species interactions influence, and are they influenced by, that spatial and temporal variation?From 2019 to 2021, we intensively sampled eight headwater streams to characterise reciprocal fluxes of aquatic and terrestrial invertebrates and the patterns of potential responses by fish, birds, bats and spiders. We evaluated sites individually as well as how they contributed to a meta‐community.We found that local stream‐riparian ecosystems contributed to a mosaic in which reciprocal fluxes of invertebrates among local patches were asynchronous and tracked by both aquatic and terrestrial consumers in ways mediated by organism traits. Within sites, aquatic and terrestrial invertebrate fluxes were seasonally asynchronous with each other, but these patterns varied from site to site. Across the mosaic, comparisons of daily aquatic insect emergence varied from 25% to 167% among streams and did so variably throughout the year, revealing asynchronous dynamics created at the meta‐community scale. Daily inputs of terrestrial invertebrates were similarly asynchronous across the mosaic, varying from 14% to 170%. These asynchronies were positively correlated with invertebrate beta diversity and associated with varying riparian vegetation, stream temperature, and flow regimes. In turn, in situ consumers tracked the allochthonous invertebrate prey in ways that were mediated by site context (i.e., local habitat characteristics) and consumer traits (e.g., range, foraging strategy and breeding requirements).Based on these observations as an example, we infer there is not one way for food webs to be reciprocally and spatially linked, but multiple ways that can vary both across a spatial mosaic and through time. Our findings provide empirical evidence suggesting potential relationships between habitat complexity and the maintenance of biodiversity via aquatic‐terrestrial reciprocal fluxes and dynamic interdependence across mosaics. 

Abstract Changing climate conditions are expected to cause increases in the frequency and severity of drought conditions in many areas around the world, including the Pacific Northwest region of North America. While drought impacts manifest across the landscape, headwater streams are particularly susceptible to droughts due to limited deep‐water habitats and low water volumes that allow for substantial increases in water temperature. While low volumes of water and increased stream temperature will likely affect all aquatic species to some degree, the response of different taxa to these impacts is expected to vary with differences in physiological needs and habitat preferences among species. Using a before–after control‐impact (BACI) experimental design, this study investigates how reduced streamflow and increased stream temperature affect the two dominant apex predators in headwater streams of the Pacific Northwest, coastal cutthroat trout (Oncorhynchus clarkii clarkii) and coastal giant salamander (Dicamptodon tenebrosus). In a second‐order stream in the H.J. Andrews Experimental Forest in OR, USA, experimental flow diversions created decoupled drought conditions of reduced streamflow and elevated temperatures. Low‐flow conditions were created by diverting water around a 100‐m stream reach and this diverted water was passively warmed before re‐entering a downstream channel to create an increased temperature reach. We compared fish and salamander abundances and stream habitat in an upstream unmanipulated reference reach to the two experimental reaches. Relative increases in temperature ranged between 0.41 and 0.63°C, reflecting realistic stream warming in this region during drought events. Trout responded positively to increased temperatures, showing an increase in abundance, biomass, condition factor, and growth, whereas salamanders responded negatively in all metrics except condition. The low‐flow reach diverted approximately 50% of the flow, resulting in a relative pool area reduction of about 20%. Relative to the reference reach, salamanders displayed a net positive abundance response while trout declined in the low‐flow reach. The contrasting responses of these populations to decoupled drought conditions suggest that interactions of flow and temperature changes together will influence drought responses of the vertebrate communities of headwater streams. 

{"Abstract":["Three distinct reaches in McRae Creek west tributary (MCTW) within the HJ Andrews Experimental Forest in western Oregon were designated for manipulation and data collection. Manipulations included increasing the temperature (T), reducing streamflow (Q), and a reference (R reach). Population estimates of vertebrates, specifically Coastal Cutthroat Trout and Coastal Giant Salamander, were obtained using three-pass depletion methods in each reach. A Before-After-Control-Impact (BACI) design was implemented, distinguishing between the "Before" and "After" periods. "Before" surveys were conducted from July 18th to 20th, 2022, while "After" surveys occurred from September 8th to 9th, 2022. During the surveys, each species was identified, noting life stage, and relevant measurements were taken. For trout, these included the length from the snout to the tail fork (Length_Fork_Vent), the snout to the tail (Length_Tail), and weight. In the "Before" survey, all trout were tagged with elastomer tags: red for the T reach, yellow for the Q reach, and orange for the R reach. Trout larger than 80 mm also received PIT tags in their abdominal cavities. Salamanders were measured similarly, not elastomer or PIT tags were applied. During the "After" survey, no new elastomer or PIT tags were inserted; only previously tagged fish were recorded. Additionally, stream cross-sections were surveyed every 5 meters to document stream dimensions. Recorded data included the location, reach, sample date, BACI status, and distance downstream from the upstream cross-section (0 meters). Measurements at each cross-section included wetted width, bankfull width, and depths at five evenly spaced points. Furthermore, pools were identified and measured in each reach, noting the maximum pool depth, depth at the outflow, width, and length. Temperature sensors were installed in each reach, recording stream temperature every 15 minutes. Sensor locations were recorded as the distance downstream from the top of each reach."]} 

Abstract As we contemplate the future of forest landscapes under changing climate conditions and land‐use demands, there is increasing value in studying historic forest conditions and how these landscapes have changed following past disturbances. Historic landscape paintings are a potential source of data on preindustrial forests with highly detailed, full‐color depictions of overstory and understory environments. They display key details about forest community composition, microhabitat features, and structural complexity from a time well before the advent of color photography. Despite these paintings' potential, their scientific applications have been impeded by questions of validity. How truly accurate are the images portrayed in these paintings? How much of an image is an artist's manipulation of a scene to best illustrate an allegory or romanticized view of nature? Following an established assessment model from historical ecology for evaluating resource validity, we demonstrate how scholarship on art history can be integrated with ecological understanding of forest landscapes to follow this model and address these questions of image veracity in 19th century American art. Further, to illustrate the potential use of these historic images in ecological studies, we present in a case study assessing microhabitat features of 10 different paintings. While this paper explores 19th century landscape art broadly, we focus our art historical review in particular on Asher Durand, a prolific and influential artist associated with the so‐called “Hudson River School” in the mid‐1800s. Durand left clear records about his perspectives on accurately depicting nature, and from a review of images and writings of Durand, we find support for the potential use of many of his paintings and sketches in historic forest ecology research. However, we also identify important caveats regarding potential ecological interpretations from these images. More broadly, because 19th century landscape paintings are not always directly transcriptive, and because regional art cultures differed in the 1800s, we cannot within this paper speak about landscape image veracity across all 19th century landscape art. However, in following established methods in historical ecology and integrating tools from art history research, we show that one can identify accurate historic landscape paintings for application in scientific studies. 

Many headwaters across temperate North America have uniform mid‐succession riparian forests recovering from historic land clearing. These young riparian stands contrast with late‐succession forests, which have complex structural characteristics including canopy gaps. Canopy gaps provide structural diversity that can be important for terrestrial species, and they are also hypothesized to be important features for aquatic environments. The light patches below gaps create productivity hotspots in streams and therefore create potential for increased stream apex predator abundances through bottom‐up food web drivers. However, increasing light may also affect stream temperature, a consideration for coldwater fish (salmonids). We established an experimental before‐after control‐impact study to explicitly assess how creating canopy gaps in the riparian forest affects the abundance and biomass of coastal cutthroat trout (Oncorhynchus clarkii clarkii) and Pacific giant salamanders (Dicamptodon tenebrosus) in paired reference and treatment reaches at five replicate streams. Gaps were designed to resemble those in old‐growth forests in the treatment reach of each system although wood was explicitly left out of the stream. At four of five sites, we found small and generally consistent positive responses in adult cutthroat trout and total vertebrate biomass to localized increases in light but only 2 years after treatment. Results suggest that opening riparian canopies adjacent to streams via gaps is a viable tool to enhance structural complexity of riparian forests without negatively impacting stream vertebrates; however, a single gap alone had small effects on aquatic vertebrates. More or larger gaps would likely be needed to notably enhance aquatic apex predators.