Roadside habitat: Boon or bane for pollinating insects?

Pollinators, which provide vital services to wild ecosystems and agricultural crops, are facing global declines and habitat loss. As undeveloped land becomes increasingly scarce, much focus has been directed recently to roadsides as potential target zones for providing floral resources to pollinators. Roadsides, however, are risky places for pollinators, with threats from vehicle collisions, toxic pollutants, mowing, herbicides, and more. Although these threats have been investigated, most studies have yet to quantify the costs and benefits of roadsides to pollinators and, therefore, do not address whether the costs outweigh the benefits for pollinator populations using roadside habitats. In this article, we address how, when, and under what conditions roadside habitats may benefit or harm pollinators, reviewing existing knowledge and recommending practical questions that managers and policymakers should consider when planning pollinator-focused roadside management.

Bumble bee diet breadth increases with local abundance and phenophase duration, not intraspecific variation in body size.

Patterns of abundance across space and time, and intraspecific variation in body size, are two species attributes known to influence diet breadth and the structure of interaction networks. Yet, the relative influence of these attributes on diet breadth is often assumed to be equal among taxonomic groups, and the relationship between intraspecific variation in body size on interaction patterns is frequently neglected. We observed bee-flower interactions in multiple locations across Montana, USA, for two growing seasons and measured spatial and temporal patterns of abundance, along with interspecific and intraspecific variation in body size for prevalent species. We predicted that the association between spatial and temporal patterns of abundance and intraspecific variation in body size, and diet breadth, would be stronger for bumble bee compared to non-bumble bee species, because species with flexible diets and long activity periods can interact with more food items. Bumble bees had higher local abundance, occurred in many local communities, more intraspecific variation in body size, and longer phenophases compared to non-bumble bee species, but only local abundance and phenophase duration had a stronger positive association with the diet breadth of bumble bee compared to non-bumble bee species. Communities with a higher proportion of bumble bees also had higher intraspecific variation in body size at the network-level, and network-level intraspecific variation in body size was positively correlated with diet generalization. Our findings highlight that the association between species attributes and diet breadth changes depending on the taxonomic group, with implications for the structure of interaction networks.

Mycorrhizae influence plant vegetative and floral traits and intraspecific trait variation.

PREMISE: Arbuscular mycorrhizal fungi (AMF) can strongly influence host plant vegetative growth, but less is known about AMF effects on other plant traits, the relative impacts of AMF on vegetative growth versus floral traits, or AMF-induced intraspecific variation in traits. METHODS: In an experimental greenhouse study, we inoculated seven species of wildflowers with six species of AMF in a factorial design. We assessed how the AMF-forb combinations influenced plant survival, vegetative biomass, and floral traits and whether AMF effects on floral traits were similar in magnitude and direction to effects on vegetative biomass. For one forb species, we investigated intraspecific plant trait variation within and across AMF treatments. RESULTS: AMF species varied from negative to positive in their effects on host plants. AMF often had inconsistent effects on vegetative biomass versus floral traits, and therefore, quantifying one or the other may provide a misleading representation of potential AMF effects. AMF treatments generated key variation in plant traits, especially floral traits, with potential consequences for plant-pollinator interactions. Given increased intraspecific trait variation in Linum lewisii plants across AMF species compared to uninoculated individuals or single AMF treatments, local AMF diversity and their host plant associations may scale up to influence community-wide patterns of trait variation and species interactions. CONCLUSIONS: These results have implications for predicting how aboveground communities are affected by belowground communities. Including AMF effects on not just host plant biomass but also functional traits and trait variation will deepen our understanding of community structure and function, including pollination.

Characterization Factors to Assess Land Use Impacts on Pollinator Abundance in Life Cycle Assessment.

While wild pollinators play a key role in global food production, their assessment is currently missing from the most commonly used environmental impact assessment method, Life Cycle Assessment (LCA). This is mainly due to constraints in data availability and compatibility with LCA inventories. To target this gap, relative pollinator abundance estimates were obtained with the use of a Delphi assessment, during which 25 experts, covering 16 nationalities and 45 countries of expertise, provided scores for low, typical, and high expected abundance associated with 24 land use categories. Based on these estimates, this study presents a set of globally generic characterization factors (CFs) that allows translating land use into relative impacts to wild pollinator abundance. The associated uncertainty of the CFs is presented along with an illustrative case to demonstrate the applicability in LCA studies. The CFs based on estimates that reached consensus during the Delphi assessment are recommended as readily applicable and allow key differences among land use types to be distinguished. The resulting CFs are proposed as the first step for incorporating pollinator impacts in LCA studies, exemplifying the use of expert elicitation methods as a useful tool to fill data gaps that constrain the characterization of key environmental impacts.

[Evolution of Emergency Department Characteristics in Child and Adolescent Psychiatry: A Retrospective Review over Two Decades]. / Entwicklung der Charakteristika von Notaufnahmen in der Kinder- und Jugendpsychiatrie.

Evolution of Emergency Department Characteristics in Child and Adolescent Psychiatry: A Retrospective Review over Two Decades Abstract. Objective: Emergency inpatient admissions to child and adolescent psychiatric hospitals because of a mental health crisis represent a substantial proportion of all inpatient admissions and have increased substantially over time. This study examines changes in the characteristics of this patient group at a university care clinic over two decades. Method: We evaluated the emergency admissions from 1996, 2002, 2008, and 2014 of the Child and Adolescent Psychiatry Clinic in Tübingen retrospectively using sociodemographic data, psychosocial circumstances, and diagnoses. Results: We evaluated a total of N = 403 emergency admissions. The emergency admissions in the periods mentioned increased by 405 %. Especially patients from families with separated parents and with multiple diagnoses increased over time. Conclusions: From 1996 to 2014, there was a significant increase in emergency admissions. The results also indicate that more complex disease situations and less favorable psychosocial conditions are occurring. The findings underscore the need to improve the clinical care of children and adolescents during acute mental health crises and work toward their prevention. There is also a need to focus broad societal discussion on improving overall mental health during childhood development. There is an urgent need for prospective studies to identify the factors leading to the increase in emergency admissions among children and adolescents.

Uncovering patterns of freshwater positive interactions using meta-analysis: Identifying the roles of common participants, invasive species and environmental context.

Positive interactions are sensitive to human activities, necessitating synthetic approaches to elucidate broad patterns and predict future changes if these interactions are altered or lost. General understanding of freshwater positive interactions has been far outpaced by knowledge of these important relationships in terrestrial and marine ecosystems. We conducted a global meta-analysis to evaluate the magnitude of positive interactions across freshwater habitats. In 340 studies, we found substantial positive effects, with facilitators increasing beneficiaries by, on average, 81% across all taxa and response variables. Mollusks in particular were commonly studied as both facilitators and beneficiaries. Amphibians were one group benefiting the most from positive interactions, yet few studies investigated amphibians. Invasive facilitators had stronger positive effects on beneficiaries than non-invasive facilitators. We compared positive effects between high- and low-stress conditions and found no difference in the magnitude of benefit in the subset of studies that manipulated stressors. Future areas of research include understudied facilitators and beneficiaries, the stress gradient hypothesis, patterns across space or time and the influence of declining taxa whose elimination would jeopardise fragile positive interaction networks. Freshwater positive interactions occur among a wide range of taxa, influence populations, communities and ecosystem processes and deserve further exploration.

Seeing through the static: the temporal dimension of plant-animal mutualistic interactions.

Most studies of plant-animal mutualistic networks have come from a temporally static perspective. This approach has revealed general patterns in network structure, but limits our ability to understand the ecological and evolutionary processes that shape these networks and to predict the consequences of natural and human-driven disturbance on species interactions. We review the growing literature on temporal dynamics of plant-animal mutualistic networks including pollination, seed dispersal and ant defence mutualisms. We then discuss potential mechanisms underlying such variation in interactions, ranging from behavioural and physiological processes at the finest temporal scales to ecological and evolutionary processes at the broadest. We find that at the finest temporal scales (days, weeks, months) mutualistic interactions are highly dynamic, with considerable variation in network structure. At intermediate scales (years, decades), networks still exhibit high levels of temporal variation, but such variation appears to influence network properties only weakly. At the broadest temporal scales (many decades, centuries and beyond), continued shifts in interactions appear to reshape network structure, leading to dramatic community changes, including loss of species and function. Our review highlights the importance of considering the temporal dimension for understanding the ecology and evolution of complex webs of mutualistic interactions.

High-severity wildfire limits available floral pollen quality and bumble bee nutrition compared to mixed-severity burns.

High-severity wildfires, which can homogenize floral communities, are becoming more common relative to historic mixed-severity fire regimes in the Northern Rockies of the U.S. High-severity wildfire could negatively affect bumble bees, which are typically diet generalists, if floral species of inadequate pollen quality dominate the landscape post-burn. High-severity wildfires often require more time to return to pre-burn vegetation composition, and thus, effects of high-severity burns may persist past initial impacts. We investigated how wildfire severity (mixed- vs. high-severity) and time-since-burn affected available floral pollen quality, corbicular pollen quality, and bumble bee nutrition using percent nitrogen as a proxy for pollen quality and bumble bee nutrition. We found that community-weighted mean floral pollen nitrogen, corbicular pollen nitrogen, and bumble bee nitrogen were greater on average by 0.82%N, 0.60%N, and 1.16%N, respectively, in mixed-severity burns. This pattern of enhanced floral pollen nitrogen in mixed-severity burns was likely driven by the floral community, as community-weighted mean floral pollen percent nitrogen explained 87.4% of deviance in floral community composition. Only bee percent nitrogen varied with time-since-burn, increasing by 0.33%N per year. If these patterns persist across systems, our findings suggest that although wildfire is an essential ecosystem process, there are negative early successional impacts of high-severity wildfires on bumble bees and potentially on other pollen-dependent organisms via reductions in available pollen quality and nutrition. This work examines a previously unexplored pathway for how disturbances can influence native bee success via altering the nutritional landscape of pollen.

Plant traits moderate pollen limitation of introduced and native plants: a phylogenetic meta-analysis of global scale.

The role of pollination in the success of invasive plants needs to be understood because invasives have substantial effects on species interactions and ecosystem functions. Previous research has shown both that reproduction of invasive plants is often pollen limited and that invasive plants can have high seed production, motivating the questions: How do invasive populations maintain reproductive success in spite of pollen limitation? What species traits moderate pollen limitation for invaders? We conducted a phylogenetic meta-analysis with 68 invasive, 50 introduced noninvasive and 1931 native plant populations, across 1249 species. We found that invasive populations with generalist pollination or pollinator dependence were less pollen limited than natives, but invasives and introduced noninvasives did not differ. Invasive species produced 3× fewer ovules/flower and >250× more flowers per plant, compared with their native relatives. While these traits were negatively correlated, consistent with a tradeoff, this did not differ with invasion status. Invasive plants that produce many flowers and have floral generalisation are able to compensate for or avoid pollen limitation, potentially helping to explain the invaders' reproductive successes.

Drought and increased CO2 alter floral visual and olfactory traits with context-dependent effects on pollinator visitation.

Climate change can alter species interactions essential for maintaining biodiversity and ecosystem function, such as pollination. Understanding the interactive effects of multiple abiotic conditions on floral traits and pollinator visitation are important to anticipate the implications of climate change on pollinator services. Floral visual and olfactory traits were measured from individuals of four forb species subjected to drought or normal water availability, and elevated or ambient concentrations of CO2 in a factorial design. Pollinator visitation rates and community composition were observed in single-species and multi-species forb assemblages. Drought decreased floral visual traits and pollinator visitation rates but increased volatile organic compound (VOC) emissions, whereas elevated CO2 positively affected floral visual traits, VOC emissions and pollinator visitation rates. There was little evidence of interactive effects of drought and CO2 on floral traits and pollinator visitation. Interestingly, the effects of climate treatments on pollinator visitation depended on whether plants were in single- or multi-species assemblages. Components of climate change altered floral traits and pollinator visitation, but effects were modulated by plant community context. Investigating the response of floral traits, including VOCs, and context-dependency of pollinator attraction provides additional insights and may aid in understanding the overall effects of climate change on plant-pollinator interactions.

Drought and leaf herbivory influence floral volatiles and pollinator attraction.

The effects of climate change on species interactions are poorly understood. Investigating the mechanisms by which species interactions may shift under altered environmental conditions will help form a more predictive understanding of such shifts. In particular, components of climate change have the potential to strongly influence floral volatile organic compounds (VOCs) and, in turn, plant-pollinator interactions. In this study, we experimentally manipulated drought and herbivory for four forb species to determine effects of these treatments and their interactions on (1) visual plant traits traditionally associated with pollinator attraction, (2) floral VOCs, and (3) the visitation rates and community composition of pollinators. For all forbs tested, experimental drought universally reduced flower size and floral display, but there were species-specific effects of drought on volatile emissions per flower, the composition of compounds produced, and subsequent pollinator visitation rates. Moreover, the community of pollinating visitors was influenced by drought across forb species (i.e. some pollinator species were deterred by drought while others were attracted). Together, these results indicate that VOCs may provide more nuanced information to potential floral visitors and may be relatively more important than visual traits for pollinator attraction, particularly under shifting environmental conditions.

The beta-diversity of species interactions: Untangling the drivers of geographic variation in plant-pollinator diversity and function across scales.

PREMISE OF THE STUDY: Geographic patterns of biodiversity have long inspired interest in processes that shape the assembly, diversity, and dynamics of communities at different spatial scales. To study mechanisms of community assembly, ecologists often compare spatial variation in community composition (beta-diversity) across environmental and spatial gradients. These same patterns inspired evolutionary biologists to investigate how micro- and macro-evolutionary processes create gradients in biodiversity. Central to these perspectives are species interactions, which contribute to community assembly and geographic variation in evolutionary processes. However, studies of beta-diversity have predominantly focused on single trophic levels, resulting in gaps in our understanding of variation in species-interaction networks (interaction beta-diversity), especially at scales most relevant to evolutionary studies of geographic variation. METHODS: We outline two challenges and their consequences in scaling-up studies of interaction beta-diversity from local to biogeographic scales using plant-pollinator interactions as a model system in ecology, evolution, and conservation. KEY RESULTS: First, we highlight how variation in regional species pools may contribute to variation in interaction beta-diversity among biogeographic regions with dissimilar evolutionary history. Second, we highlight how pollinator behavior (host-switching) links ecological networks to geographic patterns of plant-pollinator interactions and evolutionary processes. Third, we outline key unanswered questions regarding the role of geographic variation in plant-pollinator interactions for conservation and ecosystem services (pollination) in changing environments. CONCLUSIONS: We conclude that the largest advances in the burgeoning field of interaction beta-diversity will come from studies that integrate frameworks in ecology, evolution, and conservation to understand the causes and consequences of interaction beta-diversity across scales.

Predicting plant-pollinator interactions: concepts, methods, and challenges.

Plant-pollinator interactions are ecologically and economically important, and, as a result, their prediction is a crucial theoretical and applied goal for ecologists. Although various analytical methods are available, we still have a limited ability to predict plant-pollinator interactions. The predictive ability of different plant-pollinator interaction models depends on the specific definitions used to conceptualize and quantify species attributes (e.g., morphological traits), sampling effects (e.g., detection probabilities), and data resolution and availability. Progress in the study of plant-pollinator interactions requires conceptual and methodological advances concerning the mechanisms and species attributes governing interactions as well as improved modeling approaches to predict interactions. Current methods to predict plant-pollinator interactions present ample opportunities for improvement and spark new horizons for basic and applied research.

Diversity and distribution of orchid bees (Hymenoptera: Apidae, Euglossini) in Belize.

Background: Orchid bees are abundant and widespread in the Neotropics, where males are important pollinators of orchids they visit to collect fragrant chemicals later used to court females. Assemblages of orchid bees have been intensively surveyed in parts of Central America, but less so in Belize, where we studied them during the late-wet and early-dry seasons of 2015-2020. Methods: Using bottle-traps baited with chemicals known to attract a variety of orchid bee species, we conducted surveys at sites varying in latitude, historical annual precipitation, elevation, and the presence of nearby agricultural activities. Each sample during each survey period consisted of the same number of traps and the same set of chemical baits, their positions randomized along transects. Results: In 86 samples, we collected 24 species in four genera: Euglossa (16 species), Eulaema (3), Eufriesea (3), and Exaerete (2). During our most extensive sampling (December 2016-February 2017), species diversity was not correlated with latitude, precipitation, or elevation; species richness was correlated only with precipitation (positively). However, a canonical correspondence analysis indicated that species composition of assemblages varied across all three environmental gradients, with species like Eufriesea concava, Euglossa imperialis, and Euglossa viridissima most common in the drier north, and Euglossa ignita, Euglossa purpurea, and Eulaema meriana more so in the wetter southeast. Other species, such as Euglossa tridentata and Eulaema cingulata, were common throughout the area sampled. Mean species diversity was higher at sites with agricultural activities than at sites separated from agricultural areas. A Chao1 analysis suggests that other species should yet be found at our sites, a conclusion supported by records from adjacent countries, as well as the fact that we often added new species with repeated surveys of the same sites up through early 2020, and with the use of alternative baits. Additional species may be especially likely if sampling occurs outside of the months/seasons that we have sampled so far.

Shifts in pollinator composition and behavior cause slow interaction accumulation with area in plant-pollinator networks.

Although ecologists have a solid understanding of the positive species-area relationship, little is known about how and why variation in habitat area influences the richness, structure, and function of species interaction networks. To address this, we investigated plant-pollinator interaction networks of the herbaceous rocky outcrop communities in Ozark glades (Missouri, USA) of different areas. We quantified the degree to which the increase in the number of species interactions with area differed from a null model based on sampling, where numbers of individuals increase with area. Although plant-pollinator interactions were expected to increase more steeply with area than species richness as a result of sampling, the observed rate of increase was considerably lower than expected. Two mechanisms could lead to this pattern: a higher proportion of specialist species in larger glades or generalist pollinators becoming more selective in their diets in larger glades. We found support for the former hypothesis, and those changes in species composition were strong enough to outweigh behavioral changes in the opposite direction; generalist pollinators were more selective in smaller glades. If these results are general, larger habitats may be needed to conserve interactions than would be thought based on species accumulation curves.

Effects of an invasive plant transcend ecosystem boundaries through a dragonfly-mediated trophic pathway.

Trophic interactions can strongly influence the structure and function of terrestrial and aquatic communities through top-down and bottom-up processes. Species with life stages in both terrestrial and aquatic systems may be particularly likely to link the effects of trophic interactions across ecosystem boundaries. Using experimental wetlands planted with purple loosestrife (Lythrum salicaria), we tested the degree to which the bottom-up effects of floral density of this invasive plant could trigger a chain of interactions, changing the behavior of terrestrial flying insect prey and predators and ultimately cascading through top-down interactions to alter lower trophic levels in the aquatic community. The results of our experiment support the linkage of terrestrial and aquatic food webs through this hypothesized pathway, with high loosestrife floral density treatments attracting high levels of visiting insect pollinators and predatory adult dragonflies. High floral densities were also associated with increased adult dragonfly oviposition and subsequently high larval dragonfly abundance in the aquatic community. Finally, high-flower treatments were coupled with changes in zooplankton species richness and shifts in the composition of zooplankton communities. Through changes in animal behavior and trophic interactions in terrestrial and aquatic systems, this work illustrates the broad and potentially cryptic effects of invasive species, and provides additional compelling motivation for ecologists to conduct investigations that cross traditional ecosystem boundaries.

The role of timing in intraspecific trait ecology.

Intraspecific trait variation has tremendous importance for species interactions and community composition. A major source of intraspecific trait variation is an organism's developmental stage; however, timing is rarely considered in studies of the ecological effects of intraspecific variation. Here, we examine the role of time in the ecology of intraspecific trait variation, focusing on plants and their interactions with other organisms. Trait variation due to differences in developmental timing has unique features and dynamics, distinguishing it from variation due to genes or the environment. When time is considered in studies of intraspecific trait ecology, the degree of variability in timing within a population becomes a key factor structuring trait-mediated ecological interactions and community processes.

Effects of Temperature and Wildflower Strips on Survival and Macronutrient Stores of the Alfalfa Leafcutting Bee (Hymenoptera: Megachilidae) Under Extended Cold Storage.

Megachile rotundata (F.) is an important pollinator of alfalfa in the United States. Enhancing landscapes with wildflowers is a primary strategy for conserving pollinators and may improve the sustainability of M. rotundata. Changing cold storage temperatures from a traditionally static thermal regime (STR) to a fluctuating thermal regime (FTR) improves overwintering success and extends M. rotundata's shelf life and pollination window. Whether floral resources enhance overwintering survival and/or interact with a thermal regime are unknown. We tested the combined effects of enhancing alfalfa fields with wildflowers and thermal regime on survival and macronutrient stores under extended cold storage (i.e., beyond one season). Megachile rotundata adults were released in alfalfa plots with and without wildflower strips. Completed nests were harvested in September and stored in STR. After a year, cells were randomly assigned to remain in STR for 6 months or in FTR for a year of extended cold storage; emergence rates were observed monthly. Macronutrient levels of emerged females were assessed. FTR improved M. rotundata survival but there was no measurable effect of wildflower strips on overwintering success or nutrient stores. Timing of nest establishment emerged as a key factor: offspring produced late in the season had lower winter survival and dry body mass. Sugars and glycogen stores increased under FTR but not STR. Trehalose levels were similar across treatments. Total lipid stores depleted faster under FTR. While wildflowers did not improve M. rotundata survival, our findings provide mechanistic insight into benefits and potential costs of FTR for this important pollinator.

The effect of natural disturbances on forest biodiversity: an ecological synthesis.

Disturbances alter biodiversity via their specific characteristics, including severity and extent in the landscape, which act at different temporal and spatial scales. Biodiversity response to disturbance also depends on the community characteristics and habitat requirements of species. Untangling the mechanistic interplay of these factors has guided disturbance ecology for decades, generating mixed scientific evidence of biodiversity responses to disturbance. Understanding the impact of natural disturbances on biodiversity is increasingly important due to human-induced changes in natural disturbance regimes. In many areas, major natural forest disturbances, such as wildfires, windstorms, and insect outbreaks, are becoming more frequent, intense, severe, and widespread due to climate change and land-use change. Conversely, the suppression of natural disturbances threatens disturbance-dependent biota. Using a meta-analytic approach, we analysed a global data set (with most sampling concentrated in temperate and boreal secondary forests) of species assemblages of 26 taxonomic groups, including plants, animals, and fungi collected from forests affected by wildfires, windstorms, and insect outbreaks. The overall effect of natural disturbances on α-diversity did not differ significantly from zero, but some taxonomic groups responded positively to disturbance, while others tended to respond negatively. Disturbance was beneficial for taxonomic groups preferring conditions associated with open canopies (e.g. hymenopterans and hoverflies), whereas ground-dwelling groups and/or groups typically associated with shady conditions (e.g. epigeic lichens and mycorrhizal fungi) were more likely to be negatively impacted by disturbance. Across all taxonomic groups, the highest α-diversity in disturbed forest patches occurred under moderate disturbance severity, i.e. with approximately 55% of trees killed by disturbance. We further extended our meta-analysis by applying a unified diversity concept based on Hill numbers to estimate α-diversity changes in different taxonomic groups across a gradient of disturbance severity measured at the stand scale and incorporating other disturbance features. We found that disturbance severity negatively affected diversity for Hill number q = 0 but not for q = 1 and q = 2, indicating that diversity-disturbance relationships are shaped by species relative abundances. Our synthesis of α-diversity was extended by a synthesis of disturbance-induced change in species assemblages, and revealed that disturbance changes the ß-diversity of multiple taxonomic groups, including some groups that were not affected at the α-diversity level (birds and woody plants). Finally, we used mixed rarefaction/extrapolation to estimate biodiversity change as a function of the proportion of forests that were disturbed, i.e. the disturbance extent measured at the landscape scale. The comparison of intact and naturally disturbed forests revealed that both types of forests provide habitat for unique species assemblages, whereas species diversity in the mixture of disturbed and undisturbed forests peaked at intermediate values of disturbance extent in the simulated landscape. Hence, the relationship between α-diversity and disturbance severity in disturbed forest stands was strikingly similar to the relationship between species richness and disturbance extent in a landscape consisting of both disturbed and undisturbed forest habitats. This result suggests that both moderate disturbance severity and moderate disturbance extent support the highest levels of biodiversity in contemporary forest landscapes.

The future of plant-pollinator diversity: understanding interaction networks across time, space, and global change.

Structural analysis of plant-pollinator networks has revealed remarkably high species and interaction diversity and highlighted the species important for pollination services. Although techniques to analyze plant-pollinator networks began to emerge a decade ago, the characterization of spatiotemporal variation of interactions is still in its infancy. Understanding the ecological and evolutionary causes and consequences of spatial and temporal variation in plant-pollinator interactions is important for both basic and applied questions in community structure and function, the evolution of floral traits, and the development of optimal conservation strategies. Here we review observational, theoretical, and experimental studies of temporal and spatial variation in plant-pollinator interaction networks to establish a foundation for future studies to incorporate perspectives in spatiotemporal variation. Such perspectives are crucial given the rapid environmental changes associated with habitat loss, climate change, and biological invasions, which we discuss in this context. The inherent plasticity of plant-pollinator interactions and network structure suggests that many species should be able to persist by responding to environmental changes quickly, even though the identity of their mutualistic partners may change.