Tick-, Mosquito-, and Rodent-Bourne Parasite Sampling Designs for the National Ecological Observatory Network

Parasites and pathogens are increasingly recognized as significant drivers of ecological and evolutionary change in natural ecosystems. Concurrently, transmission of infectious agents among human, livestock, and wildlife populations represents a growing threat to veterinary and human health. In light of these trends and the scarcity of long-term time series data on infection rates among vectors and reservoirs, the National Ecological Observatory Network (NEON) will collect measurements and samples of a suite of tick-, mosquito-, and rodent-borne parasites through a continental-scale surveillance program. Here, we describe the sampling designs for these efforts, highlighting sampling priorities, field and analytical methods, and the data as well as archived samples to be made available to the research community. Insights generated by this sampling will advance current understanding of and ability to predict changes in infection and disease dynamics in novel, interdisciplinary, and collaborative ways

Connectivity: insights from the U.S. Long Term Ecological Research Network

Ecosystems across the United States are changing in complex and surprising ways. Ongoing demand for critical ecosystem services requires an understanding of the populations and communities in these ecosystems in the future. This paper represents a synthesis effort of the U.S. National Science Foundation-funded Long-Term Ecological Research (LTER) network addressing the core research area of “populations and communities.” The objective of this effort was to show the importance of long-term data collection and experiments for addressing the hardest questions in scientific ecology that have significant implications for environmental policy and management. Each LTER site developed at least one compelling case study about what their site could look like in 50–100 yr as human and environmental drivers influencing specific ecosystems change. As the case studies were prepared, five themes emerged, and the studies were grouped into papers in this LTER Futures Special Feature addressing state change, connectivity, resilience, time lags, and cascading effects. This paper addresses the “connectivity” theme and has examples from the Phoenix (urban), Niwot Ridge (alpine tundra), McMurdo Dry Valleys (polar desert), Plum Island (coastal), Santa Barbara Coastal (coastal), and Jornada (arid grassland and shrubland) sites. Connectivity has multiple dimensions, ranging from multi-scalar interactions in space to complex interactions over time that govern the transport of materials and the distribution and movement of organisms. The case studies presented here range widely, showing how land-use legacies interact with climate to alter the structure and function of arid ecosystems and flows of resources and organisms in Antarctic polar desert, alpine, urban, and coastal marine ecosystems. Long-term ecological research demonstrates that connectivity can, in some circumstances, sustain valuable ecosystem functions, such as the persistence of foundation species and their associated biodiversity or, it can be an agent of state change, as when it increases wind and water erosion. Increased connectivity due to warming can also lead to species range expansions or contractions and the introduction of undesirable species. Continued long-term studies are essential for addressing the complexities of connectivity. The diversity of ecosystems within the LTER network is a strong platform for these studies

Tick-, Mosquito-, and Rodent-Borne Parasite Sampling Designs for the National Ecological Observatory Network [Special Feature: NEON Design]

Parasites and pathogens are increasingly recognized as significant drivers of ecological and evolutionary change in natural ecosystems. Concurrently, transmission of infectious agents among human, livestock, and wildlife populations represents a growing threat to veterinary and human health. In light of these trends and the scarcity of long-term time series data on infection rates among vectors and reservoirs, the National Ecological Observatory Network (NEON) will collect measurements and samples of a suite of tick-, mosquito-, and rodent-borne parasites through a continental-scale surveillance program. Here, we describe the sampling designs for these efforts, highlighting sampling priorities, field and analytical methods, and the data as well as archived samples to be made available to the research community. Insights generated by this sampling will advance current understanding of and ability to predict changes in infection and disease dynamics in novel, interdisciplinary, and collaborative ways

Macroinvertebrate fauna of an iron-rich stream in the wet tropics of Australia: a comparative analysis of communities using a rapid bioassessment protocol

The present study examined an iron-rich stream in the Wet Tropics of Queensland, Australia, and used a Rapid Bioassessment Protocol to compare its macroinvertebrate fauna with that of (1) a nearby, undisturbed stream and (2) the second order stream formed from their junction. The undisturbed stream supported significantly greater levels of macroinvertebrate abundance and taxonomic richness than either the iron-rich or junction stream. The latter two streams did not differ significantly for either measure, suggesting that iron-layering effects maintain potency even at increased distances from the source (>1 km). Percent Similarity (PSij) and Shannon-Weiner Diversity (H′) indices were used to compare the streams' macroinvertebrate communities, while two biotic indices (SIGNAL) were employed to estimate water quality. The undisturbed stream exhibited greater invertebrate diversity and higher water quality relative to the other two streams. Species assemblage patterns were comparable to iron-rich stream studies from the temperate region: mayfly and caddisfly nymphs were almost completely absent from the sites of iron-deposition while they comprised the majority of the invertebrates in the undisturbed stream. The conservation issues and management implications surrounding the release of water from stratified dams and reservoirs are discussed

Data from: Parasite metacommunities: evaluating the roles of host community composition and environmental gradients in structuring symbiont communities within amphibians

1. Ecologists increasingly report the structures of metacommunities for free-living species, yet far less is known about the composition of symbiont communities through space and time. Understanding the drivers of symbiont community patterns has implications ranging from emerging infectious disease to managing host microbiomes. 2. Using symbiont communities from amphibian hosts sampled from wetlands of California, USA, we quantified the effects of spatial, habitat filtering, and host community components on symbiont occupancy and overall metacommunity structure. 3. We built upon a statistical method to describe metacommunity structure that accounts for imperfect detection in survey data – detection error-corrected elements of metacommunity structure (DECEMS) – by adding an analysis to identify covariates of community turnover. We applied our model to a metacommunity of 8 parasite taxa observed in 3571 Pacific chorus frogs (Pseudacris regilla) surveyed from 174 wetlands over 5 years. 4. Symbiont metacommunity structure varied across years, showing nested structure in three years and random structure in two years. Species turnover was most consistently influenced by spatial and host community components. Occupancy generally increased in more southeastern wetlands, and snail (intermediate-host) community composition had strong effects on most symbiont taxa. 5. We have used sophisticated but accessible statistical methods to reveal that spatial components - which influence colonization - and host community composition - which mediates transmission - both drive symbiont community composition in this system. These methods allow us to associate broad patterns of community turnover to local, species-level effects, ultimately improving our understanding of spatial community dynamics

Diverging effects of host density and richness across biological scales drive diversity-disease outcomes

The data and analyses support results published in Johnson et al. 2024 Nature Communications (Diverging effects of host density and richness across biological scales drive diversity-disease outcomes). The data include estimates of trematode infections from multiple amphibian species, alongside predictors of transmission (e.g., infection pressure, host species richness, host densities, predator densities, amphibian competence). See "README.doc" for a guide to the data files and R scripts. All methods are included in the associated publication.All data were collected with the approval of the University of Colorado's Institutional Animal Care and Use Committee (protocol 1002.021302.01) and in accordance with sampling protocols approved by the California Department of Fish and Wildlife (SC-3683 and SC-10560) and the Santa Clara County Parks, East Bay Regional Parks District, East Bay Municipal Utility District, California State Parks and other local landowners</p

Data from: Experimental investigation of alternative transmission functions: quantitative evidence for the importance of non-linear transmission dynamics in host-parasite systems

1. Understanding pathogen transmission is crucial for predicting and managing disease. Nonetheless, experimental comparisons of alternative functional forms of transmission remain rare, and those experiments that are conducted are often not designed to test the full range of possible forms. 2. To differentiate among ten candidate transmission functions, we used a novel experimental design in which we independently varied four factors—duration of exposure, numbers of parasites, numbers of hosts, and parasite density—in laboratory infection experiments. 3. We used interactions between amphibian hosts and trematode parasites as a model system and all candidate models incorporated parasite depletion. An additional manipulation involving anesthesia addressed the effects of host behaviour on transmission form. 4. Across all experiments, non-linear transmission forms involving either a power law or a negative binomial function were the best-fitting models and consistently outperformed the linear density-dependent and density-independent functions. By testing previously published data for two other host-macroparasite systems, we also found support for the same non-linear transmission forms. 5. Although manipulations of parasite density are common in transmission studies, the comprehensive set of variables tested in our experiments revealed that variation in density alone was least likely to differentiate among competing transmission functions. Across host-pathogen systems, non-linear functions may often more accurately represent transmission dynamics and thus provide more realistic predictions for infection

Data from: Experimental investigation of alternative transmission functions: quantitative evidence for the importance of non-linear transmission dynamics in host-parasite systems

1. Understanding pathogen transmission is crucial for predicting and managing disease. Nonetheless, experimental comparisons of alternative functional forms of transmission remain rare, and those experiments that are conducted are often not designed to test the full range of possible forms. 2. To differentiate among ten candidate transmission functions, we used a novel experimental design in which we independently varied four factors—duration of exposure, numbers of parasites, numbers of hosts, and parasite density—in laboratory infection experiments. 3. We used interactions between amphibian hosts and trematode parasites as a model system and all candidate models incorporated parasite depletion. An additional manipulation involving anesthesia addressed the effects of host behaviour on transmission form. 4. Across all experiments, non-linear transmission forms involving either a power law or a negative binomial function were the best-fitting models and consistently outperformed the linear density-dependent and density-independent functions. By testing previously published data for two other host-macroparasite systems, we also found support for the same non-linear transmission forms. 5. Although manipulations of parasite density are common in transmission studies, the comprehensive set of variables tested in our experiments revealed that variation in density alone was least likely to differentiate among competing transmission functions. Across host-pathogen systems, non-linear functions may often more accurately represent transmission dynamics and thus provide more realistic predictions for infection

The role of warm, dry summers and variation in snowpack on phytoplankton dynamics in mountain lakes

Climate change is altering biogeochemical, metabolic, and ecological functions in lakes across the globe. Historically, mountain lakes in temperate regions have been unproductive because of brief ice-free seasons, a snowmelt-driven hydrograph, cold temperatures, and steep topography with low vegetation and soil cover. We tested the relative importance of winter and summer weather, watershed characteristics, and water chemistry as drivers of phytoplankton dynamics. Using boosted regression tree models for 28 mountain lakes in Colorado, we examined regional, intraseasonal, and interannual drivers of variability in chlorophyll a as a proxy for lake phytoplankton. Phytoplankton biomass was inversely related to the maximum snow water equivalent (SWE) of the previous winter, as others have found. However, even in years with average SWE, summer precipitation extremes and warming enhanced phytoplankton biomass. Peak seasonal phytoplankton biomass coincided with the warmest water temperatures and lowest nitrogen-to-phosphorus ratios. Although links between snowpack, lake temperature, nutrients, and organic-matter dynamics are increasingly recognized as critical drivers of change in high-elevation lakes, our results highlight the additional influence of summer conditions on lake productivity in response to ongoing changes in climate. Continued changes in the timing, type, and magnitude of precipitation in combination with other globalchange drivers (e.g., nutrient deposition) will affect production in mountain lakes, potentially shifting these historically oligotrophic lakes toward new ecosystem states. Ultimately, a deeper understanding of these drivers and pattern at multiple scales will allow us to anticipate ecological consequences of global change better