An official website of the United States government
Songbird reproductive success can decline from consuming mercury-contaminated aquatic insects, but assessments of hydrologic conditions influencing songbird mercury exposure are lacking. We monitored breast feather total mercury (THg) concentrations and reproductive success in the U.S. federally listed endangered Cape Sable Seaside Sparrow (CSSS: Ammospiza maritima mirabilis) over three breeding seasons in the Florida Everglades. We used model comparison to explore the influence of annual hydrologic variation on adult CSSS THg concentrations, and tested mercury effects on individual reproductive success (individuals’ mate status, apparent nest success, and total productivity) that were scaled to estimates on population productivity using a demographic model. We identified four hydrologic models that explained annual variation in adult THg concentrations, with the top model showing a negative association between THg concentrations and drought length of the previous breeding season and a positive association between THg concentrations and dry-season water recession rate (model adjusted R2 = 0.82). Adult male mating probability declined by 63% across the range of THg concentrations observed. We found no mercury effect on CSSS nest success or total productivity. However, demographic modeling suggested the reduced mating could produce a 60% decrease in population productivity compared to a scenario with no THg impact. Our results suggest that CSSS mercury exposure is influenced by local hydrologic conditions that can increase early breeding failure (lack of breeding initiation) and potentially limit population productivity. This study is the first to describe CSSS mercury exposure and its potential reproductive costs at the individual and population levels.
more »
« less
Cape Sable Seaside Sparrow (Ammospiza maritima mirabilis) breast feather total mercury concentrations from the Florida Everglades, Florida, USA: breeding seasons 2016 - 2018
This dataset was used to determine hydrologic parameters influencing Cape Sable Seaside Sparrow (CSSS) mercury exposure and potential mercury effects on their reproductive success in the Florida Everglades. We collected breast feathers for total mercury determination from juvenile and adult CSSS during (or shortly after) three breeding seasons (March 1 to July 31) and monitored the same individuals' breeding performance (mate status, number of nest attempts, number of successful nest attempts, total productivity of nests, clutch size, total count of eggs, and hatch success). Hydrologic parameters (average water depths, drought length, water recession rate, and hydroperiod) were estimated using the Everglades Depth Estimation Network and in situ depth measurements. Data collection is complete.
more »
« less
- PAR ID:
- 10643705
- Publisher / Repository:
- Environmental Data Initiative
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
{"Abstract":["Environmental and diatom data were collected from sites in the Big Cypress National Preserve (BICY) by the South Florida/Caribbean Inventory and Monitoring Network of the National Park Service and from sites in the Everglades Protection Area (EPA) as part of the Monitoring and Assessment Program of the Comprehensive Everglades Restoration Plan. Samples from years 2012, 2013, 2019, 2019, and 2020 are included in this dataset. Environmental data include drier variables that have been found to influence diatom assemblage composition in the greater Everglades ecosystem, including periphyton mat total phosphorus (a proxy for phosphorus in the environment), water column pH, water column conductivity, water depth, days since last dry, and hydroperiod. Diatom data include diatom species composition as percent relative abundances. Code included is pertinent to the methods described in "Robust species optima estimates from non-uniformly sampled environmental gradients" by Solomon et al. 2025, Journal of Paleolimnology."]}more » « less
-
Abstract Emergent marsh and open water have been identified as alternate stable states in tidal marshes with large, relative differences in hydrogeomorphic conditions. In the Florida coastal Everglades, concern has been raised regarding the loss of non-tidal, coastal peat marsh via dieback of emergent vegetation and peat collapse. To aid in the identification of alternate stable states, our objective was to characterize the variability of hydrogeomorphic and biologic conditions using a field survey and long-term monitoring of hydrologic and geomorphic conditions across a range of vegetated (emergent, submerged) and unvegetated (open water) communities, which we refer to as “ecosystem states,” in a non-tidal, brackish peat marsh of the coastal Everglades. Results show (1) linear relationships among field-surveyed geomorphic, hydrologic, and biologic variables, with a 35-cm mean difference in soil surface elevation between emergent and open water states, (2) an overall decline in soil elevation in the submerged state that was related to cumulative dry days, and (3) a 2× increase in porewater salinity during the dry season in the emergent state that was also related to the number of dry days. Coupled with findings from previous experiments, we propose a conceptual model that describes how seasonal hydrologic variability may lead to ecosystem state transitions between emergent and open water alternate states. Since vegetative states are only moderately salt tolerant, as sea-level rise pushes the saltwater front inland, the importance of continued progress on Everglades restoration projects, with an aim to increase the volume of freshwater being delivered to coastal wetlands, is the primary management intervention available to mitigate salinization and slow ecosystem state shifts in non-tidal, brackish peat marshes.more » « less
-
Climate and human modifications, including restoration, are changing freshwater availability in wetland ecosystems. Changes in spatiotemporal variability in water depth can influence biogeochemistry and aquatic metabolism (net ecosystem productivity, gross primary productivity [GPP], and ecosystem respiration [ER]). In subtropical wetlands, flocculent organic matter (floc) is a dominant form of organic matter made up of periphyton, macrophytes, and microbes. How changes in water depth with climate and human modifications of subtropical wetlands influence biogeochemistry and the metabolism of floc is uncertain and necessary to understand the consequences for carbon (C) cycling. We collected seasonal floc samples from shorter‐hydroperiod marshes (Taylor Slough Panhandle [TS/Ph]) and longer‐hydroperiod marshes (Shark River Slough [SRS]) in Everglades National Park (Florida, U.S.A.). We measured floc‐specific metabolism and biogeochemistry during the wet (May–November) and dry seasons (December–April) when marsh conditions differed in water depth, photosynthetically active radiation (PAR), floc chlorophylla, bulk density, and C and nutrients. Floc biogeochemistry was driven by hydrologic changes in water depth, while floc metabolism was influenced by floc biogeochemistry and PAR in both marshes. Floc‐specific metabolism was more net heterotrophic (GPP < ER) in TS/Ph than in SRS, driven by floc bulk density, total nitrogen, total C, total phosphorus, and total inorganic C. Increasing water depths with freshwater restoration may drive higher rates of C loss in shallower compared to deeper marshes. Understanding how hydrologic changes affect organic matter lability and respiration is important in managing C storage in ecosystems.more » « less
-
Doi, Hideyuki (Ed.)A central tenant of the Comprehensive Everglades Restoration Plan (CERP) is nutrient reduction to levels supportive of ecosystem health. A particular focus is phosphorus. We examine links between agricultural production and phosphorus concentration in the Everglades headwaters: Kissimmee River basin and Lake Okeechobee, considered an important source of water for restoration efforts. Over a span of 47 years we find strong correspondence between milk production in Florida and total phosphate in the lake, and, over the last decade, evidence that phosphorus concentrations in the lake water column may have initiated a long-anticipated decline.more » « less
