![[Old] Chesapeake Research Consortium](https://chesapeake.org/wp-content/uploads/2017/01/LogoForDarkBack.png)
- were subjected to external peer-review and accessible through library services;
- were published after January 1, 2016;
- were authored or co-authored by individuals employed with one of the seven principal CRC member institutions or with other major Chesapeake Bay Program partners; and
- have direct relevance to the science and/or management of the Chesapeake Bay or its watershed.
Further details about the the submission process can be found here. Further details about the purpose and "value added" of the RCCP collection (relative to other on-line databases) can be found here.
Prior predation alters community resistance to an extreme climate disturbance
Short-term physical disturbances occur amid a backdrop of longer-term biotic interactions, including predation, which shape communities. Effects of consumer interactions typically begin in early stages of assembly and continue throughout post-disturbance recovery. Despite decades of predation and disturbance research, few studies examine how consumer interactions during these different time periods may affect community responses to disturbance. Here we use replicate communities of tropical, sessile invertebrates to ask whether fish predation during initial assembly (before) and recovery (after) influences community resistance to a hurricane-level low-salinity event. Results revealed that pre-event predation determined whether communities shifted in biomass and community structure following disturbance. Communities that assembled without predators responded to the low-salinity event strongly, with large shifts in community composition and a mean loss of 54% of pre-disturbance biomass after a one-month recovery period. In contrast, those that experienced predation during initial assembly were strikingly resistant to disturbance, which had no effect on species composition or biomass. Results were driven by predator removal of a dominant competitor, which gave rise to more disturbance-resistant communities. These findings highlight the potential for past trophic interactions to shape community stability in the face of physical disturbances predicted to escalate with global change.
Get PDFIncreased grassland arthropod production with mammalian herbivory and eutrophication: a test of mediation pathways
Increases in nutrient availability and alterations to mammalian herbivore communities are a hallmark of the Anthropocene, with consequences for the primary producer communities in many ecosystems. While progress has advanced understanding of plant community responses to these perturbations, the consequences for energy flow to higher trophic levels in the form of secondary production are less well understood. We quantified arthropod biomass after manipulating soil nutrient availability and wild mammalian herbivory, using identical methods across 13 temperate grasslands. Of experimental increases in nitrogen, phosphorus, and potassium, only treatments including nitrogen resulted in significantly increased arthropod biomass. Wild mammalian herbivore removal had a marginal, negative effect on arthropod biomass, with no interaction with nutrient availability. Path analysis including all sites implicated nutrient content of the primary producers as a driver of increased arthropod mean size, which we confirmed using 10 sites for which we had foliar nutrient data. Plant biomass and physical structure mediated the increase in arthropod abundance, while the nitrogen treatments accounted for additional variation not explained by our measured plant variables. The mean size of arthropod individuals was 2.5 times more influential on the plot-level total arthropod biomass than was the number of individuals. The eutrophication of grasslands through human activity, especially nitrogen deposition, thus may contribute to higher production of arthropod consumers through increases in nutrient availability across trophic levels.
Get PDFPhosphorus uptake and availability and short-term seedling growth in three Ontario soils amended with ash and biochar
Phosphorus (P) can be a limiting nutrient in terrestrial ecosystems and adding biochar or wood ash can increase plant-available P. We added wood ash and biochar to microcosms containing three acidic Ontario soils planted with red pine or sugar maple seedlings and observed seedling growth responses, as well as amendment-induced changes in soil P pools, microbial P, and enzyme activity. Neither ash nor biochar consistently increased seedling growth; instead sugar maple and red pine seedlings often had opposing responses to the same amendment–soil combination. Overall, these results indicate that it is important to carefully consider both the chemical and physical characteristics of the soil and the ash or biochar, as well as the nutrient requirements of the target tree species, to effectively use these amendments to reduce P limitation.
Get PDFPhylogeography and connectivity of molluscan parasites: Perkinsus spp. in Panama and beyond
Panama is a major hub for commercial shipping between two oceans, making it an ideal location to examine parasite biogeography, potential invasions, and the spread of infectious agents. Our goals were to (i) characterise the diversity and genetic connectivity of Perkinsus spp. haplotypes across the Panamanian Isthmus and (ii) combine these data with sequences from around the world to evaluate the current phylogeography and genetic connectivity of these widespread molluscan parasites. We collected 752 bivalves from 12 locations along the coast of Panama including locations around the Bocas del Toro archipelago and the Caribbean and Pacific entrances to the Panama Canal, from December 2012 to February 2013. We used molecular genetic methods to screen for Perkinsus spp. and obtained internal transcribed spacer region (ITS) ribosomal DNA (rDNA) sequences for all positive samples. Our sequence data were used to evaluate regional haplotype diversity and distribution across both coasts of Panama, and were then combined with publicly available sequences to create global haplotype networks. We found 26 ITS haplotypes from four Perkinsus spp. (1–12 haplotypes per species) in Panama. Perkinsus beihaiensis haplotypes had the highest genetic diversity, were the most regionally widespread, and were associated with the greatest number of hosts. On a global scale, network analyses demonstrated that some haplotypes found in Panama were cosmopolitan (Perkinsus chesapeaki, Perkinsus marinus), while others were more geographically restricted (Perkinsus olseni, P. beihaiensis), indicating different levels of genetic connectivity and dispersal. We found some Perkinsus haplotypes were shared across the Isthmus of Panama and several regions around the world, including across ocean basins. We also found that haplotype diversity is currently underestimated and directly related to the number of sequences. Nevertheless, our results demonstrate long-range dispersal and global connectivity for many haplotypes, suggesting that dispersal through shipping probably contributes to these biogeographical patterns.
Get PDFLatitude, temperature and habitat complexity predict predation pressure in eelgrass beds across the Northern Hemisphere
Latitudinal gradients in species interactions are widely cited as potential causes or consequences of global patterns of biodiversity. However, mechanistic studies documenting changes in interactions across broad geographic ranges are limited. We surveyed predation intensity on common prey (live amphipods and gastropods) in communities of eelgrass (Zostera marina) at 48 sites across its Northern Hemisphere range, encompassing over 37° of latitude and four continental coastlines. Predation on amphipods declined with latitude on all coasts but declined more strongly along western ocean margins where temperature gradients are steeper. Whereas in situ water temperature at the time of the experiments was uncorrelated with predation, mean annual temperature strongly positively predicted predation, suggesting a more complex mechanism than simply increased metabolic activity at the time of predation. This large-scale biogeographic pattern was modified by local habitat characteristics; predation declined with higher shoot density both among and within sites. Predation rates on gastropods, by contrast, were uniformly low and varied little among sites. The high replication and geographic extent of our study not only provides additional evidence to support biogeographic variation in predation intensity, but also insight into the mechanisms that relate temperature and biogeographic gradients in species interactions.
Get PDFAsynchrony among local communities stabilises ecosystem function of metacommunities
Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species-level abundance data from 62 plant communities across five continents to assess mechanisms of temporal stability across spatial scales. We assessed how asynchrony (i.e. different units responding dissimilarly through time) of species and local communities stabilised metacommunity ecosystem function. Asynchrony of species increased stability of local communities, and asynchrony among local communities enhanced metacommunity stability by a wide range of magnitudes (1–315%); this range was positively correlated with the size of the metacommunity. Additionally, asynchronous responses among local communities were linked with species’ populations fluctuating asynchronously across space, perhaps stemming from physical and/or competitive differences among local communities. Accordingly, we suggest spatial heterogeneity should be a major focus for maintaining the stability of ecosystem services at larger spatial scales.
Get PDFThe Financial Impact of Different Stormwater Fee Types: A Case Study of Two Municipalities in Virginia
Eight stormwater user fees (SUFs) were applied to the City of Roanoke and the Town of Blacksburg, Virginia, to determine the effect each has on how land use type impacts the sources of revenue. Roanoke is larger and includes more industrial areas, but less multifamily impervious areas than Blacksburg, which translates differently in the SUFs. Residential parcels comprise the highest percentage of the revenue in all eight SUFs in Blacksburg and four in Roanoke. For both municipalities, two specific SUFs consistently comprised the highest percentage burden for residential homeowners while three other SUFs demonstrated the highest burden for commercial parcels. Open space parcels contain little impervious area, yet account for up to 27% of the revenue in the Blacksburg Area fee structure. Industrial parcels comprise more revenue in Roanoke, averaging 10.1-4.5% in Blacksburg. Fee types that are easier to administer (e.g., Flat fees) may not fully represent the stormwater contribution from the parcels. SUF types that more accurately represent the stormwater burden on the municipality are also more administratively intensive and are more variable with fee factors.
Get PDFEvaluation of Continuous Monitoring as a Tool for Municipal Stormwater Management Programs
The purpose of this study is to evaluate the uncertainty attributable to inadequate temporal sampling of stormwater discharge and water quality, and understand its implications for meeting monitoring objectives relevant to municipal separate storm sewer systems (MS4s). A methodology is presented to evaluate uncertainty attributable to inadequate temporal sampling of continuous stormflow and water quality, and a case study demonstrates the application of the methodology to six small urban watersheds (0.8–6.8km2 0.8 – 6.8 km 2 ) and six large rural watersheds (30–16,192km2 30 – 16,192 km 2 ) in Virginia. Results indicate the necessity of high-frequency continuous monitoring for accurately capturing multiple monitoring objectives, including illicit discharges, acute toxicity events, and stormflow pollutant concentrations and loads, as compared to traditional methods of sampling. For example, 1-h sampling in small urban watersheds and daily sampling in large rural watersheds would introduce uncertainty in capturing pollutant loads of 3–46% and 10–28%, respectively. Overall, the outcomes from this study highlight how MS4s can leverage continuous monitoring to meet multiple objectives under current and future regulatory environments.
Get PDFExperiences of Green Building Professionals with Water Related Systems
An internet survey sent to green building professionals explored the level of users' satisfaction with several water-saving products and methods.
Get PDF