Ecological Monographs Research Articles

Cool‐Blooded Bees for Cool‐Weather Flowers

Photo 1. The Sierra de Cazorla mountains in southeastern Spain, where the study was carried out. The area is characterized by rugged topography, high habitat and species diversity, and outstanding degree of preservation of natural vegetation. Photo credit: Carlos M. Herrera. Photo 2. As in many other mountain areas from mid-latitudes of the Holarctic realm, the flowering season in plant communities of the Sierra de Cazorla starts well before the end of winter, when ambient temperatures are still cool even in the clearest, sunniest days. Some plants living at high elevations, as the daffodil Narcissus longispathus (Amaryllidaceae) shown in the picture, sometimes have to face the latest snowfalls of the winter while already bearing open flowers. Photo credit: Carlos M. Herrera. Photo 3. A sampler of early-blooming plants from the Sierra de Cazorla area having mining bees of the genus Andrena as their main pollinators. Clockwise from the top left (percentage of bee pollinators contributed by species of Andrena shown in parentheses): Iberis carnosa (Brassicaceae, 100%); Hepatica nobilis (Ranunculaceae, 80%); Crocus nevadensis (Iridaceae, 79%); Draba hispanica (Brassicaceae, 71%); Narcissus hedraeanthus (Amaryllidaceae, 67%); and Fritillaria lusitanica (Liliaceae, 63%). Photo credit: Carlos M. Herrera. Photo 4. The genus Andrena is the second largest genus of bees, with ~1,600 described species worldwide. They pollinate many wild plants in boreal and temperate habitats of Eurasia and North America, particularly species flowering in winter and early spring. Out of the nearly 100 Andrena species recorded to date from the Sierra de Cazorla region, 30 were included in our study on their thermal ecology. Some of these are featured in these pictures. Clockwise from the top left: Andrena baetica (on Ornithogalum umbellatum, Asparagaceae); Andrena bicolor (on Primula acaulis, Primulaceae); Andrena congruens (on Eryngium campestre, Apiaceae); Andrena fulva (on Rosmarinus officinalis, Lamiaceae); Andrena lagopus (on Diplotaxis catholica, Brassicaceae); Andrena nigroaenea (on Erodium cheilanthifolium, Geraniaceae); Andrena sardoa (on Asphodelus cerasiferus, Xanthorrhoeaceae); and Andrena trimmerana (on Berberis hispanica, Berberidaceae). Photo credit: Carlos M. Herrera. These photographs illustrate the article “Seasonality of pollinators in Mediterranean montane habitats: cool-blooded bees for early-blooming plants” by Carlos M. Herrera, Alejandro Núñez, Luis O. Aguado and Conchita Alonso published in Ecological Monographs. https://doi.org/10.1002/ecm.1570

Geology‐Climate Interactions are Key Determinants of Climate‐Change Refugia in Japanese Mountain Streams

Photo 1. Example of the confluence of a volcanic and nonvolcanic stream (left panel). The right panel is a thermal photograph of the confluence taken using a TVS-500 camera (Nippon Avionics Co., Ltd.) on September 17, 2019, where blue colors correspond to the cold water from the volcanic stream mixing with the warmer (orange) water from the nonvolcanic stream. Photo credit: Kenta Iwasaki. Photo 2. View of a volcanic stream, Ponnunobe stream, the Sorachi river, Hokkaido, Japan. The stream is located inside the University of Tokyo Hokkaido Forest. Many springs (top panels) occur in around the main channel (bottom panel). In this region, the mean summer water temperature of volcanic streams is 3°C colder than that of nonvolcanic streams on average. Photo credit: Yu Nagasaka. Photo 3. Wrinklehead sculpin (upper panel: Cottus nozawae) and Southern Asian Dolly Varden (lower panel: Salvelinus curilus) two major cold-water species in northern Japan. Their distribution is tightly restricted by summer water temperature. Photo credit: Yu Nagasaka (upper panel) and Chiharu Furusawa (lower panel). Photo 4. View of biotic and abiotic surveys in mountain streams, Japan. Macroinvertebrates (upper left panel) and fish (lower left panel) were collected once in each monitoring stream. Water loggers were installed with short sections of perforated PVC pipes to facilitate water exchange and shield them from sunlight (right panels). Photo credit: Jorge García Molinos. Photo 5. Dynamic changes in riverscapes at a monitoring site due to a large flood associated with Typhoon Hagibis, 2019 (before: upper panel, after: lower panel). Monitoring of water temperature in the Japanese archipelago is very challenging because of the many typhoons hitting the archipelago every summer season. Unfortunately, the temperature data of this site in 2019 was not available due to the loss of the logger. The yellow bridge at the upper-left corner of the picture offers a good visual reference to compare both pictures. Photo credit: Nobuo Ishiyama. These photographs illustrate the article “Underlying geology and climate interactively shape climate change refugia in mountain streams” by Ishiyama, N., Sueyoshi, M., García Molinos, J., Iwasaki, K., Negishi, J. N., Koizumi, I., Nagayama, S., Nagasaka, A., Nagasaka, Y. & Nakamura, F. published in Ecological Monographs. https://doi.org/10.1002/ecm.1566

Plant community data collected by Robert H. Whittaker in the Siskiyou Mountains, Oregon and California, USA.

In 1949-1951, ecologist Robert H. Whittaker sampled plant community composition at 470 sites in the Siskiyou Mountains (Oregon and California; also known as Klamath or Klamath-Siskiyou Mountains). His primary goal was to develop methods to quantify plant community variation across environmental gradients, following on his seminal work challenging communities as discrete entities. He selected the Siskiyous because of their diverse and endemic-rich flora, which he attributed to geological complexity and an ancient stable climate. He chose sites to span gradients of topography, elevation, geologic substrate, and distance from the coast. He used the frequencies of indicator species in his data to assign sampling locations to positions on the topographic gradient, nested within the elevational and substrate gradients. He originated in this study the concept of diversity partitioning, in which gamma diversity (species richness of a community) equals alpha diversity (species richness in homogeneous sites) times beta diversity (species turnover among sites along gradients). Diversity partitioning subsequently became highly influential and new developments on it continue. Whittaker published his Siskiyou work covering paleohistory, biogeography, floristics, vegetation, gradient analysis, and diversity partitioning in Ecological Monographs in 1960. Discussed in 2 pages of his 60-page monograph, diversity partitioning accounts for >95% of its current >4300 citations. In 2006, we retrieved Whittaker's Siskiyou data in hard copy from the Cornell University archives and entered them in a database. We used these data for multiple published analyses, including some based on (re)sampling the approximate locations of a subset of his sites. Because of the continued interest in diversity partitioning and in historic data sets, here we present his data, including 359 sampling locations and their descriptors and, for each sample, a list of species with their estimated percent cover (herbs and shrubs) and numbers by diameter at breast height (DBH) category (trees). Site descriptors include the approximate location (road, trail, or stream), elevation, topographic aspect, geologic substrate (serpentine, gabbro, or diorite), and dominant woody vegetation of each location. For 111 sites, including the small number chosen to represent the distance-to-coast gradient, we could not locate his data. There are no copyright restrictions and users of these data should cite this data paper in any publications that result from its use. The authors are available for consultations about and collaborations involving the data.

Metabolic Acclimation at Multiple Levels and Vulnerabilities to Climate Warming Across Latitudes

Photo 1. A female Takydromus wolteri basking. The photograph was taken during the lizard collection. Photo credit: Lai-gao Luo. Photo 2. A female Takydromus septentrionalis. The photograph was taken during the lizard collection. Photo credit: Hong-liang Lu. Photo 3. A male Takydromus sexlineatus basking. The photograph was taken during the lizard collection. Photo credit: Bao-jun Sun. These photographs illustrate the article “Higher metabolic plasticity in temperate compared to tropical lizards suggests increased resilience to climate change” by Baojun Sun, Caroline M. Williams, Teng Li, John R. Speakman, Zengguang Jin, Hongliang Lu, Laigao Luo, and Weiguo Du, published by Ecological Monographs. https://doi.org/10.1002/ecm.1512.

Trait‐based Inference of Ecological Network Assembly: A Conceptual Framework and Methodological Toolbox

Photo 1. Foothill humid forests in the Andes of southern Ecuador. Photo Credit: Eike Lena Neuschulz. Photo 2. The Andean forest near sunset. Photo Credit: Eike Lena Neuschulz. Photo 3. Vegetation diversity in the Andean forest. Photo Credit: Eike Lena Neuschulz. Photo 4. Sharp elevational changes shape biodiversity in the Andes. Photo Credit: Eike Lena Neuschulz. Photo 5. Grey-breasted mountain toucan looking for some fruit. Photo Credit: Matthias Schleuning. These photographs illustrate the article “Trait-based inference of ecological network assembly: a conceptual framework and methodological toolbox” by Emma-Liina Marjakangas, Gabriel Muñoz, Shaun Turney, Jörg Albrecht, Eike Lena Neuschulz, Matthias Schleuning, and Jean-Philippe Lessard published in Ecological Monographs. https://doi.org/10.1002/ecm.1502.

Fungi Living in Plant Roots have Low Habitat and Host Specificities, But Highly Restricted Distributions

Photo 1. A sampling site in the Veluwe region, The Netherlands, with local fauna. Photo credit: Jose G. Maciá-Vicente Photo 2. Collection of plant samples in a grassland at Los Alcornocales Natural Park, in southern Spain. Photo credit: Jose G. Maciá-Vicente Photo 3. An Eriophorum sp. plant being dug out at Fulufjället National Park, in Sweden. Photo credit: Jose G. Maciá-Vicente Photo 4. Processing of root samples in the laboratory, back in Frankfurt am Main in Germany. Photo credit: Jose G. Maciá-Vicente Photo 5. Microscope images of fungal hyphae (arrows) colonizing roots of different plant species. All images were taken at 100× magnification. Photo credit: Jose G. Maciá-Vicente These photographs illustrate the article “Local endemism and ecological generalism in the assembly of root-colonizing fungi” by Jose G. Maciá-Vicente and Flavius Popa published in Ecological Monographs. https://doi.org/10.1002/ecm.1489

Embryonic Thermal Tolerance Shapes the Vulnerability of lizards to Climate Change

Photo 1. A female northern grass lizard Takydromus septentrionalis from the high-latitude population basking at Kunyushan Mountain, Yantai, China. The photo was taken during lizard collection. Photo credit: Bao-jun Sun. Photo 2. A male northern grass lizard T. septentrionalis from the high-latitude population basking at Kunyushan Mountain, Yantai, China. Photo credit: Bao-jun Sun. Photo 3. A juvenile northern grass lizard T. septentrionalis from the high-latitude population searching for food at Kunyushan Mountain, Yantai, China. Photo credit: Bao-jun Sun. These photographs illustrate the article “Latitudinal embryonic thermal tolerance and plasticity shape the vulnerability of oviparous species to climate change” by Bao-jun Sun, Liang Ma, Yang Wang, Chun-rong Mi, Lauren B. Buckley, Ofir Levy, Hong-liang Lu and Wei-guo Du, published in Ecological Monographs. https://doi.org/10.1002/ecm.1468.

Solidago canadensis, a Flower or Weed?

Figure 1. Flowers or weeds? S. canadensis is one of the worst exotic weeds in China (A). Yet, farmers grow it as a cut flower (B). Because diploid cytotypes grow faster and flower earlier than other polyploids, all cultivated S. canadensis cytotypes for cut flowers are diploids. We found that diploids are sterile under hot-summer temperature south of 24°C-isotherm range and cultivation of S. canadensis will not lead to naturalization. However, the risk for naturalization increases in regions north of 20ºC-isotherm range. Photo credit: Sheng Qiang. Figure 2. Population of Solidago canadensis in native and introduced range in North America and China, respectively. S. canadensis plants are significantly taller and denser in the introduced range in China (Jiangsu) (A) than in their native range of North America (Pennsylvania, USA) (B). S. canadensis plants often outcompete native plants in invasive habitats and essentially become monoculture-type communities. Photo credit: Sheng Qiang. Figure 3. Dramatic difference in height of Solidago canadensis between native and invasive populations. S. canadensis plants can often be over 4m in height in China (Nanjing) (A), but are usually below 2m in North America (Ottawa, Canada) (B). Photo credit: Sheng Qiang. Figure 4. Field sampling site diagram. At each site, sampling plots were separated by at least 10 m to minimize the probability of sampling multiple ramets from individual genets. Photo credit: Guoqi Chen. Figure 5. Pollen germination and pollen tube growth on a stigma. (A) Pollen germination; (B) pollen tube growth; (C) penetration of pollen tubes into an ovary. Photo credit: Beibei Yao. These photographs illustrate the article “Solidago canadensis, a flower or weed?” by Sheng Qiang, Jiliang Cheng, Guoqi Chen, Beibei Yao published in Ecological Monographs. https://doi.org/10.1002/ecm.1445.

A Bed Bug is Not as Bad Anymore to its Bird Host

Photo 1. Cliff swallows are colonially nesting birds widely distributed across much of western and central North America. They build gourd-shaped mud nests, and breeding colonies can range up to 6,000 nests in size. Photo by Charles R. Brown. Photo 2. Swallow bugs are close relatives of human bed bugs and live in the cliff swallows’ mud nests or the nesting substrate year-round. They feed on blood of both nestling and adult swallows, and a single nest can contain up to 3,000 bugs. Photo by Art Gingert. Photo 3. Cliff swallows formerly nested almost exclusively on the sides of steep cliffs underneath horizontal overhangs, where colonies tended to be smaller, the nests less stable, and swallow bug populations smaller than after the birds’ switch to artificial nesting sites. Photo by Charles R. Brown. Photo 4. As artificial structures such as bridges, buildings, and highway culverts increased throughout much of North America, cliff swallows switched to nesting on these sites almost entirely in many parts of their range. This switch exposed them to more swallow bugs than when the birds used cliff nesting sites. Photo by Charles R. Brown. Photo 5. By repeating experiments from the 1980s in which we fumigated some nests in colonies to remove swallow bugs and left others exposed to natural numbers of bugs, we demonstrated that swallow bugs are less costly to cliff swallows now than they were 35 years ago. Photo by Stacey L. Hannebaum. These photographs illustrate the article “The cost of ectoparasitism in cliff swallows declines over 35 years” by Charles R. Brown, Stacey L. Hannebaum, Valerie A. O’Brien, Catherine E. Page, Bruce Rannala, Erin A. Roche, Gigi S. Wagnon, Sarah A. Knutie, Amy T. Moore, and Mary Bomberger Brown published in Ecological Monographs https://doi.org/10.1002/ecm.1446

Long‐Term Biodiversity Benefits from Invasive Mammalian Pest Control in Ecological Restorations

Photo I: 47 km of pest Xcluder™ fencing protects Sanctuary Mountain Maungatautari, New Zealand, where invasive mammalian pests have been eradicated and native species are being restored. Photo credit: Neil Fitzgerald. This photograph illustrates the article “Long-term biodiversity trajectories for pest-managed restorations: eradication vs. suppression” by Binny RN, Innes J, Fitzgerald N, Pech R, James A, Price R, Gillies C and Byrom AE published in Ecological Monographs. https://doi.org/10.1002/ecm.1439.

Cover

The Bulletin of the Ecological Society of AmericaVolume 102, Issue 2 e01878 CoverFree Access Cover First published: 01 April 2021 https://doi.org/10.1002/bes2.1878AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat Abstract COVER PHOTO: Healthy colonies of purple gorgonian, Paramuricea clavata, at 40 m depth in Illots de Ponent Marine Reserve, Ibiza, Spain. These gorgonians are an important habitat-forming species, now threatened by climate change-related warming events and other impacts. Long-term studies of the species, led by Dr. Cristina Linares, form one of the data sets used to evaluate demographic methods by Doak et al. in a recent Ecological Monographs study (https://doi.org/10.1002/ecm.1447). Photo credit: Cristina Linares. Volume102, Issue2April 2021e01878 RelatedInformation

Controls on Somatic Growth and Population Dynamics of Rainbow Trout

Photo 1: A rainbow trout holding immediately downstream of Glen Canyon Dam in the clearwater Glen Canyon reach of the Colorado River. Photo credit: David Herasimtschuk, Freshwaters Illustrated. Photo 2: Rainbow trout holding over a cobble bar in the clearwater Glen Canyon reach of the Colorado River and feeding on drifting aquatic invertebrates. Photo credit: David Herasimtschuk, Freshwaters Illustrated. Photo 3: Nighttime boat electrofishing was used to capture rainbow trout for tagging. Time-lapse photography captures the path of electrofishing boats on left and right shores. Captured fish were brought to a centrally located processing boat (foreground) to be measured, weighed, tagged, and scanned, and were then returned to their original capture site. Photo credit: Dustin Patar. Photo 4: The Marble Canyon reach of the Colorado River can be very turbid during the summer monsoon season. High turbidity reduced feeding efficiency and growth rates of rainbow trout, which, combined with higher water temperatures and reduced prey production, led to a severe collapse of the population in this reach. Photo credit: Dustin Patar. Photo 5: The confluence of the Little Colorado River (LCR, entering from top of photograph) and the Colorado River. The LCR is an important spawning and rearing area for endangered Humpback Chub. Juvenile Humpback Chub disperse from the LCR into the main stem Colorado River where their survival and growth rates are reduced due to cooler water temperature and competition and predation from non-native rainbow trout. Our sampling reaches IVa and IVb are located in the Colorado River upstream (left side of photograph) and downstream (right side of photograph) of the confluence. Occasional floods from the LCR result in high levels of turbidity downstream of the confluence which reduces growth rates and densities of rainbow trout. Photo credit: Ted Grussing, tedgrussing photography. These photographs illustrate the article “Changes in prey, turbidity, and competition reduce somatic growth and cause the collapse of a fish population” by J. Korman, M.D. Yard, M.C. Dzul, C.B. Yackulic, M.J. Dodrill, B.R. Deemer, and T.A. Kennedy published in Ecological Monographs. https://doi:10.1002/ecm.1427

In silico trio biomarkers for bacterial vaginosis revealed by species dominance network analysis

BV (bacterial vaginosis) influences 20%–40% of women but its etiology is still poorly understood. An open question about BV is which of the hundreds of bacteria found in the human vaginal microbiome (HVM) are the major force driving the vaginal microbiota dysbiosis. Here, we recast the question of microbial causality of BV by asking if there are any prevalent ‘signatures’ (network motifs) in the vaginal microbiome networks associated with it? We apply a new framework [species dominance network analysis by Ma & Ellison (2019): Ecological Monographs) to detect critical structures in HVM networks associated with BV risks and etiology. We reanalyzed the 16 s-rRNA gene sequencing datasets of a mixed-cohort of 25 BV patients and healthy women. In these datasets, we detected 15 trio motifs that occurred exclusively in BV patients. We failed to find any of these 15 trio motifs in three additional cohorts of 1535 healthy women. Most member-species of the 15 trio motifs are BV-associated anaerobic bacteria (BVAB), Ravel’s community-state type indicators, or the most dominant species; virtually all species interactions in these trios are high-salience skeletons, suggesting that those trios are strongly connected ‘cults’ associated with the occurrence of BV. The presence of the trio motifs unique to BV may act as indicators for its personalized diagnosis and could help elucidate a more mechanistic interpretation of its risks and etiology. We caution that scarcity of large longitudinal datasets of HVM also limited further verifications of our findings, and these findings require further clinical tests to launch their applications.

Food Quantity–Quality Interactions and Their Impact on Consumer Behavior and Trophic Transfer

Interactions between predator and prey species play a crucial role in defining nutrient and energy cycling in food webs. Most consumers experience frequent changes in food quantity and quality which impact their fitness. We assessed how consumers regulate their feeding behavior and digestive physiology in a new fitness-optimization model. Our results reveal that food quantity and quality show strong interactions in shaping consumer responses such as feeding, recycling, and growth rates. Our analysis shows that the inclusion of regulatory flexibility of consumers improves predictions of predator–prey dynamics and nutrient flows in food webs. Photo credit: Ole F. Nielsen. This photograph illustrates the article “Food quantity–quality interactions and their impact on consumer behavior and trophic transfer” by Alfred Burian, Jens M. Nielsen, and Monika Winder published in Ecological Monographs. https://doi.org/10.1002/ecm.1395

Density‐dependent growth and survival in salmonids: Quantifying biological mechanisms and methodological biases

AbstractUnderstanding the complex variation in patterns of density‐dependent individual growth and survival across populations is critical to adaptive fisheries management, but the extent to which this variation is caused by biological or methodological differences is unclear. Consequently, we conducted a correlational meta‐analysis of published literature to investigate the relative importance of methodological and biological predictors on the shape and strength of density‐dependent individual growth and survival in salmonids. We obtained 160 effect sizes from 75 studies of 12 species conducted between 1977 and 2019 that differed in experimental approach (sensu Ecological Monographs, 54, 187–211; 65 laboratory experiments, 60 observational field studies, and 35 field experiments). The experimental approach was the strongest factor influencing the strength of density dependence across studies: density‐dependent survival was stronger than growth in field observational studies, whereas laboratory experiments detected stronger density‐dependent growth than survival. The difference between density‐dependent growth and survival was minimal in field experiments, and between lotic and lentic habitats. The shape of density dependence (logarithmic, linear, exponential or density‐independent) could be predicted with 66.7% accuracy based solely on the experimental approach and the density gradient (highest/lowest*100) of the study. Overall, the strength and shape of density dependence were primarily influenced by methodological predictors, while biological factors (predator presence, food abundance, and species) had predictable but modest effects. For both empirical studies and adaptive fisheries management, we recommend using field experiments with a density gradient of at least 470% to detect the proper shape of the density‐dependent response, or accounting for potential biases if observational or laboratory studies are conducted.

Spatiotemporal Patterns of Microbial Composition and Diversity in Precipitation

We characterized trends of bacteria and fungi assemblages from 72 precipitation events in three US states over four seasons. We determined that (1) bacterial assemblages were associated with season and high-altitude characteristics of storms, whereas fungal assemblages were correlated with particular spatial locations; and (2) bacterial assemblages had higher contributions to total β-diversity from nestedness, due to taxa losses during dispersal, particularly among potentially ice-nucleating bacteria, whereas fungal assemblages had higher contributions to total β-diversity from taxa turnover. Our findings advance the understanding of aerosolized microbial deposition and the development of theory concerning potential assembly rules for bioaerosol assemblages. These photographs illustrate the article “Spatiotemporal patterns of microbial composition and diversity in precipitation” by K. Aho, C. F. Weber, B. C. Christner, B. A. Vinatzer, C. E. Morris, R. Joyce, K. Failor, J. T. Werth, A. L. H. Bayless-Edwards, and D. G. Schmale III, published in Ecological Monographs. https​://doi.org/10.1002/ecm.1394

Foundational biogeography: Vegetation of the Great Smoky Mountains (Ecological Monographs, 26: 1–80, 1956), by Robert H. Whittaker

A seminal paper in biogeography is reviewed. Whittaker’s 1956 paper in Ecological Monographs introduced gradient analysis as a conceptual framework. This approach replaced community classification as the preferred methodology among US ecologists and biogeographers. It later developed into the foundation for species distribution modeling. Although the paper underlies a continuing rift between US and European scientists, both groups recognize its importance for relating ecological processes to geographical patterns.

Emerging Reservoir Delta‐Backwaters: Biophysical Dynamics and Riparian Biodiversity

Dams have been built on most of the world's large rivers. Thousands more are being proposed in countries with developing economies. Dams have major ecological consequences for river systems, including the loss of native riparian forests. Sediment that historically moved downstream and sustained coastal deltas is now accumulating at tributary and mainstem confluences in reservoirs worldwide. Our study found that vegetation communities similar to those destroyed in reservoirs are re-establishing on these emerging delta-backwaters. This understudied expansion of riparian forest is compensating, to a yet unknown degree, for the massive losses of ecosystem services caused by river damming. Photo credit: Gray Tappan. Photo credit: Malia Volke. Photo credit: Malia Volke. Photo credit: Malia Volke. Photo credit: Gray Tappan. These photographs illustrate the article “Emerging reservoir delta-backwaters: biophysical dynamics and riparian biodiversity” by Malia A. Volke, W. Carter Johnson, Mark D. Dixon, Michael L. Scott published in Ecological Monographs. https://doi.org/10.1002/ecm.1363

Regional Variation in Interior Alaskan Boreal Forests is Driven by Fire Disturbance, Topography, and Climate

We developed landscape-scale spatial models of tree species occupancy and abundance in Yukon–Charley Rivers National Preserve (YCNP), a remote and little-studied region in east-central Alaska. We compared these results with similar work completed in Denali National Park (see Roland et al. 2013). These two areas are a study in contrasts. Specifically, YCNP is a highly continental region with warmer growing seasons, a topographically diverse lowland landscape, and a considerably greater footprint of recent fire disturbance. Our two study areas thus effectively frame a “natural experiment” that allowed us to examine various hypotheses regarding expected changes in the Alaskan boreal forest due to a rapidly warming climate in Alaska. These photographs illustrate the article “Regional variation in interior Alaskan boreal forests is driven by fire disturbance, topography, and climate” by Carl A. Roland, Joshua H. Schmidt, Samantha G. Winder, Sarah. E. Stehn, and E. Fleur Nicklen published in Ecological Monographs. https://doi.org/10.1002/ecm.1369

Mechanisms of Population Persistence for a Rare Endemic Plant

Small populations are particularly susceptible to extinction, and the ways that these populations persist over time is a puzzle in conservation and ecology. Understanding the mechanisms that increase the chances for small populations of rare species to persist is important to global biodiversity. Desert yellowhead is a rare endemic plant that occurs in only two small populations in central Wyoming, USA. These populations appear to have persisted with remarkable stability; spatial asynchrony in growth among subpopulations results in a portfolio effect, and negative density dependence allows the population to recover from low numbers. In the future, warmer temperatures and potentially increased variation in precipitation could diminish these stabilizing mechanisms. Photo credit: Reilly Dibner. These photographs illustrate the article “Multiple Mechanisms Confer Stability to Isolated Populations of a Rare Endemic Plant” by Reilly R. Dibner, Megan L. Peterson, Allison M. Louthan, and Daniel F. Doak published in Ecological Monographs. https://doi.org/10.1002/ecm.1360