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This is a review of over 400 published research papers on free-living, non-testate amoebae during the approximate last half century (1965-2017) particularly focusing on three topics: Biogeography, Ecology, and Physiology. These topics were identified because of the substantial attention given to them during the course of the last half century, and due to their potential importance in issues of local and global expanse, such as: aquatic and terrestrial stability of habitats, ecosystem processes, biogeochemistry and climate change, and the role of eukaryotic microbes generally in ecosystem services. Moreover, there are close epistemological and thematic ties among the three topics, making a synthesis of the published research more systematic and productive. The number of reviewed publications for each of the three individual topics is presented to illustrate the trends in publication frequencies during the historical period of analysis. Overall, the number of total publications reviewed varied somewhat between 1965 and early 2000 (generally less than 10 per year), but increased to well over 10 per year after 2000. The number of Biogeography and Ecology studies identified in the online citations increased substantially after the mid 1990s, while studies focusing on Physiology were relatively more abundant in the first decade (1965-1974) and less were identified in the 1985 to 2004 period. Citations to the literature are listed in tables for each of the three topics for convenience in retrieving references to specific aspects, and representative examples of the cited research in the tables are reviewed in the text under subheads dedicated to each of the three topics. Biogeographic studies largely focused on the geographic distribution and localized patterns of occurrence of amoebae, with more recent studies incorporating more attention to likely correlates with environmental and biotic factors in the distribution and community composition of amoebae. Ecological studies reviewed in the later decades tended to focus more on community dynamics, the effects of environmental variables on communities (including climate-related topics), a trend toward more physiological ecology studies, combined field-based and experimental studies, and incorporation of newer methodologies such as molecular genetics. In general, physiology studies in the first decades of the review tended to focus on topics of cell physiology such as basic biochemistry, enzyme assays, mechanisms of cell division and development, encystment, and motility. Later studies examined broader topics such as osmoregulation, nutrition, fine structure evidence of cellular changes during the life cycle (including encystment and excystment), and issues related to asexual and sexual reproduction, with increasing substantial evidence of evolutionary patterns and phylogenetics based on molecular evidence. A final section on Conclusions and Recommendations summarizes the findings and presents some potentially productive approaches to future research studies on Amoebozoa within the three designated topics of analysis. [ABSTRACT FROM AUTHOR]

Theory posits that community dynamics organize at distinct hierarchical scales of space and time, and that the spatial and temporal patterns at each scale are commensurate. Here we use time series modeling to investigate fluctuation frequencies of species groups within invertebrate metacommunities in 26 boreal lakes over a 20-year period, and variance partitioning analysis to study whether species groups with different fluctuation patterns show spatial signals that are commensurate with the scale-specific fluctuation patterns identified. We identified two groups of invertebrates representing hierarchically organized temporal dynamics: one species group showed temporal variability at decadal scales (slow patterns of change), whilst another group showed fluctuations at 3 to 5-year intervals (faster change). This pattern was consistently found across all lakes studied. A spatial signal was evident in the slow but not faster-changing species groups. As expected, the spatial signal for the slow-changing group coincided with broad-scale spatial patterns that could be explained with historical biogeography (ecoregion delineation, and dispersal limitation assessed through a dispersal trait analysis). In addition to spatial factors, the slow-changing groups correlated with environmental variables, supporting the conjecture that boreal lakes are undergoing environmental change. Taken together our results suggest that regionally distinct sets of taxa, separated by biogeographical boundaries, responded similarly to broad-scale environmental change. Not only does our approach allow testing theory about hierarchically structured space-time patterns; more generally, it allows assessing the relative role of the ability of communities to track environmental change and dispersal constraints limiting community structure and biodiversity at macroecological scales. [ABSTRACT FROM AUTHOR]