Annual Review of Ecology, Evolution, and Systematics

▪ Abstract  Mammals are exposed to a diverse array of parasites and infectious diseases, many of which affect host survival and reproduction. Species that live in dense populations, large social groups, or with promiscuous mating systems may be especially vulnerable to infectious diseases owing to the close proximity and higher contact rates among individuals. We review the effects of host density and social contacts on parasite spread and the importance of promiscuity and mating structure for the spread and evolution of sexually transmitted diseases. Host social organization and mating system should influence not only parasite diversity and prevalence but may also determine the fitness advantages of different transmission strategies to parasites. Because host behavior and immune defenses may have evolved to reduce the spread and pathogenicity of infectious diseases, we also consider selective pressures that parasites may exert on host social and mating behavior and the evolutionary responses of hosts at both the immunological and behavioral levels. In examining these issues, we relate modeling results to observations from wild populations, highlighting the similarities and differences among theoretical and empirical approaches. Finally, the epidemiological consequences of host sociality are very relevant to the practical issues of conserving mammalian biodiversity and understanding the interactions between extinction risk and infectious diseases.

Các phương pháp tiếp cận dựa trên đặc tính đang ngày càng được sử dụng trong sinh thái học. Cộng đồng tảo, với lịch sử phong phú về các hệ thống mô hình trong sinh thái học cộng đồng, rất lý tưởng để áp dụng và phát triển thêm các khái niệm này. Tại đây, chúng tôi tóm tắt các thành phần thiết yếu của các phương pháp dựa trên đặc tính và duyệt xét việc áp dụng lịch sử cũng như tiềm năng của chúng trong việc tìm hiểu sinh thái cộng đồng tảo. Các trục sinh thái quan trọng liên quan đến tảo bao gồm thu nhận và sử dụng ánh sáng và dinh dưỡng, tương tác với kẻ thù tự nhiên, sự biến đổi hình thái, độ nhạy cảm với nhiệt độ, và các phương thức sinh sản. Các sự đánh đổi giữa các đặc tính này đóng vai trò quan trọng trong việc xác định cấu trúc cộng đồng. Môi trường nước ngọt và biển có thể lựa chọn một chuỗi các đặc tính khác nhau do các đặc tính vật lý và hóa học khác nhau của chúng. Chúng tôi mô tả các kỹ thuật toán học để tích hợp các đặc tính vào các biện pháp tăng trưởng và thể lực và dự đoán cách cấu trúc cộng đồng thay đổi dọc theo các gradient môi trường. Cuối cùng, chúng tôi vạch ra các thách thức và định hướng tương lai cho việc áp dụng các phương pháp dựa trên đặc tính vào sinh thái học tảo.

Bivalve molluscs are abundant in marine and freshwater ecosystems and perform important ecological functions. Bivalves have epifaunal or infaunal lifestyles but are largely filter feeders that couple the water column and benthos. Bivalve ecology is a large field of study, but few comparisons among aquatic ecosystems or lifestyles have been conducted. Bivalves impact nutrient cycling, create and modify habitat, and affect food webs directly (i.e., prey) and indirectly (i.e., movement of nutrients and energy). Materials accumulated in soft tissue and shells are used as environmental monitors. Freshwater mussel and oyster aggregations in rivers and estuaries are hot spots for biodiversity and biogeochemical transformations. Historically, human use includes food, tools, currency, and ornamentation. Bivalves provide direct benefits to modern cultures as food, building materials, and jewelry and provide indirect benefits by stabilizing shorelines and mitigating nutrient pollution. Research on bivalve-mediated ecological processes is diverse, and future synthesis will require collaboration across conventional disciplinary boundaries.

Secondary tropical forests that are in a state of regeneration following clearing for agriculture are now more abundant than primary forests. Yet, despite their large spatial extent and important role in the global carbon (C) cycle, secondary tropical forests are understudied, which challenges our ability to predict how tropical landscapes will respond to future disturbance and global change. We summarize research advances on alterations to C and nutrient dynamics during reforestation and how these are influenced by ecosystem state factors. During forest succession, aboveground biomass stocks and litter fluxes increase in a predictable way, but patterns in soil C dynamics are highly variable. The heterogeneous response of nutrients to reforestation is influenced by multiple factors, including losses incurred during prior land use and management. In contrast to primary tropical forests, where productivity is often limited by rock-derived nutrients, secondary forest growth may be more limited by nutrients from the atmosphere. Future research should identify which nutrients constrain forest regrowth.

▪ Abstract  Mutualisms occur when interactions between species produce reciprocal benefits. However, the outcome of these interactions frequently shifts from positive, to neutral, to negative, depending on the environmental and community context, and indirect effects commonly produce unexpected mutualisms that have community-wide consequences. The dynamic, and context dependent, nature of mutualisms can transform consumers, competitors, and parasites into mutualists, even while they consume, compete with, or parasitize their partner species. These dynamic, and often diffuse, mutualisms strongly affect community organization and ecosystem processes, but the historic focus on pairwise interactions decoupled from their more complex community context has obscured their importance. In aquatic systems, mutualisms commonly support ecosystem-defining foundation species, underlie energy and nutrient dynamics within and between ecosystems, and provide mechanisms by which species can rapidly adjust to ecological variance. Mutualism is as important as competition, predation, and physical disturbance in determining community structure, and its impact needs to be adequately incorporated into community theory.

Seed dispersal is key to the persistence and spread of plant populations. Because the majority of plant species rely on animals to disperse their seeds, global change drivers that directly affect animals can cause cascading impacts on plant communities. In this review, we synthesize studies assessing how disperser loss alters plant populations, community patterns, multitrophic interactions, and ecosystem functioning. We argue that the magnitude of risk to plants from disperser loss is shaped by the combination of a plant species’ inherent dependence on seed dispersal and the severity of the hazards faced by their dispersers. Because the factors determining a plant species’ risk of decline due to disperser loss can be related to traits of the plants and dispersers, our framework enables a trait-based understanding of change in plant community composition and ecosystem functioning. We discuss how interactions among plants, among dispersers, and across other trophic levels also mediate plant community responses, and we identify areas for future research to understand and mitigate the consequences of disperser loss on plants globally.

This review proposes ten tentative answers to frequently asked questions about dispersal evolution. I examine methodological issues, model assumptions and predictions, and their relation to empirical data. Study of dispersal evolution points to the many ecological and genetic feedbacks affecting the evolution of this complex trait, which has contributed to our better understanding of life-history evolution in spatially structured populations. Several lines of research are suggested to ameliorate the exchanges between theoretical and empirical studies of dispersal evolution.

Genome sequence data are now being routinely obtained from many nonmodel organisms. These data contain a wealth of information about the demographic history of the populations from which they originate. Many sophisticated statistical inference procedures have been developed to infer the demographic history of populations from this type of genomic data. In this review, we discuss the different statistical methods available for inference of demography, providing an overview of the underlying theory and logic behind each approach. We also discuss the types of data required and the pros and cons of each method. We then discuss how these methods have been applied to a variety of nonmodel organisms. We conclude by presenting some recommendations for researchers looking to use genomic data to infer demographic history.

▪ Abstract  Landscape ecology focuses on the reciprocal interactions between spatial pattern and ecological processes, and it is well integrated with ecology. The field has grown rapidly over the past 15 years. The persistent influence of land-use history and natural disturbance on contemporary ecosystems has become apparent. Development of pattern metrics has largely stabilized, and they are widely used to relate landscape pattern to ecological responses. Analyses conducted at multiple scales have demonstrated the importance of landscape pattern for many taxa, and spatially mediated interspecific interactions are receiving increased attention. Disturbance remains prominent in landscape studies, and current research is addressing disturbance interactions. Integration of ecosystem and landscape ecology remains challenging but should enhance understanding of landscape function. Landscape ecology should continue to refine knowledge of when spatial heterogeneity is fundamentally important, rigorously test the generality of its concepts, and develop a more mechanistic understanding of the relationships between pattern and process.

The use of artificial lighting to illuminate the night has provided substantial benefits to humankind. It has also disrupted natural daily, seasonal, and lunar light cycles as experienced by a diversity of organisms, and hence it has also altered cues for the timings of many biological activities. Here we review the evidence for impacts of artificial nighttime lighting on these timings. Although the examples are scattered, concerning a wide variety of species and environments, the breadth of such impacts is compelling. Indeed, it seems reasonable to conclude that the vast majority of impacts of artificial nighttime lighting stem from effects on biological timings. This adds support to arguments that artificial nighttime lighting has a quite pervasive and marked impact on ecological systems, that the rapid expansion in the global extent of both direct illuminance and skyglow is thus of significant concern, and that a widespread implementation of mitigation measures is required.