The keystone species concept provides a valuable framework for integrating findings across traditional disciplines that scale from the cellular level (chemical defense and chemosensory reception) and the organismal level (behavioral traits) to the community level (species interactions). Select bioactive compounds cause disproportionately large effects by connecting such seemingly disparate processes as microbial loop dynamics and apex predation. Outstanding examples of these “molecules of keystone significance” draw on four distinct compounds: dimethylsulfoniopropionate, saxitoxin, tetrodotoxin, and pyrrolizidine alkaloids. Through convergent evolution, they inform phylogenetically diverse species; initiate major trophic cascades; and structure respective communities within terrestrial, freshwater, coastal-ocean, and open-ocean environments. Their relevance to conservation biology involves the protection of threatened species or habitats in the face of natural- and human-induced disturbances.

Traditionally, stream channel planform has been viewed as a function of larger watershed and valley-scale physical variables, including valley slope, the amount of discharge, and sediment size and load. Biotic processes serve a crucial role in transforming channel planform among straight, braided, meandering, and anabranching styles by increasing stream-bank stability and the probability of avulsions, creating stable multithread (anabranching) channels, and affecting sedimentation dynamics. We review the role of riparian vegetation and channel-spanning obstructions—beaver dams and logjams—in altering channel-floodplain dynamics in the southern Rocky Mountains, and we present channel planform scenarios for combinations of vegetation and beaver populations or old-growth forest that control logjam formation. These conceptual models provide understanding of historical planform variability throughout the Holocene and outline the implications for stream restoration or management in broad, low-gradient headwater valleys, which are important for storing sediment, carbon, and nutrients and for supporting a diverse riparian community.

A major focus in evolutionary ecology lies in explaining the evolution and maintenance of social systems. Although most theoretical formulations of social system evolution were initially inspired by studies of birds, mammals, and insects, incorporating a wider taxonomic perspective is important for testing deeply entrenched theory. Here, we review the contribution of studies of habitat-specialist coral reef fishes to our understanding of the evolutionary ecology of animal social systems. These fishes are ecologically similar but display remarkable variation in mating systems, social organization, and sex allocation strategies. By reviewing recent research, we demonstrate their amenability for experimental testing of key concepts in social evolution and for generating novel insights, including the ultimate reasons for female reproductive suppression, group living, and bidirectional sex change. Habitat-specialist reef fishes are a tried and tested group of model organisms for advancing our understanding of the evolution and ecology of social systems in animals.

Understanding how complex organisms function as integrated units that constantly interact with their environment is a long-standing challenge in biology. To address this challenge, organismal biology reveals general organizing principles of physiological systems and behavior—in particular, in complex multicellular animals. Organismal biology also focuses on the role of individual variability in the evolutionary maintenance of diversity. To broadly advance these frontiers, cross-compatibility of experimental designs, methodological approaches, and data interpretation pipelines represents a key prerequisite. It is now possible to rapidly and systematically analyze complete genomes to elucidate genetic variation associated with traits and conditions that define individuals, populations, and species. However, genetic variation alone does not explain the varied individual physiology and behavior of complex organisms. We propose that such emergent properties of complex organisms can best be explained through a renewed emphasis on the context and life-history dependence of individual phenotypes to complement genetic data.

Ecosystem-service production is strongly influenced by the landscape configuration of natural and human systems. Ecosystem services are not only produced and consumed locally but can be transferred within and among ecosystems. The time and distance between the producer and the consumer of ecosystem services can be considered lags in ecosystem-service provisioning. Incorporation of heterogeneity and lag effects into conservation incentives helps identify appropriate governance systems and incentive mechanisms for effective ecosystem-service management. These spatiotemporal dimensions are particularly apparent in river—riparian systems, which provide a suite of important ecosystem services and promote biodiversity conservation at multiple scales, including habitat protection and functional connectivity. Management of ecosystem services with spatiotemporal lags requires an interdisciplinary consideration of both the biophysical landscape features that produce services and the human actors that control and benefit from the creation of those services.

Recent increases in capabilities for gathering, storing, accessing, and sharing data are creating corresponding opportunities for scientists to use data generated by others in their own research. Although sharing data and crediting sources are among the most basic of scientific ethical principles, formal ethical guidelines for data reuse have not been articulated in the biological sciences community. This article offers a framework for developing ethical principles on data reuse, addressing issues such as citation and coauthorship, with the aim of stimulating a conversation in the science community and with the goal of having professional societies formally incorporate considerations of data reuse into their codes of ethics.

Two approaches to the estimation of relative potency for dose—time—response assays are compared: the application of a generalized linear model to the dichotomized responses and survival analysis of the time to response. Survival analysis is widely used in other fields; however, its application to bioassays has been uncommon. A description of the application of survival analysis to bioassays is provided. A worked example follows, using mouse challenge assay data. This demonstrates that estimates of relative potency based on the time to response can have considerably lower variance than those based on dichotomized responses. A simulation study further supports this conclusion. Routine use of survival analysis techniques has the potential to reduce the number of animals used in bioassay trials by ensuring that the maximum value is recovered from each animal, in line with the new European Union directive on the protection of animals used for scientific purposes.