Hydrologic Connectivity and Flow Generation from California Vernal Pool, Swale, and Headwater Stream Complexes to Downstream WatersStepchinski, Leanne M.; Rains, Mark C.; Lee, Lyndon C.; Lis, Richard A.; Nutter, Wade L.; Rains, Kai C.; Stewart, Scott R.
doi: 10.1007/s13157-023-01678-3pmid: N/A
Many headwater wetlands are integrated into flowpath networks and can serve as sources of streamflow for downgradient waters. We demonstrate this with five years of data in vernal pool, swale, and headwater stream complexes in the Central Valley, California. Long-term United States Geological Survey data suggest that the mean flow duration from the smallest watersheds in this region, including those with vernal pool, swale, and headwater stream complexes, is ~ 85 days per year. Our data concur, indicating that the annual days of flow per year from our vernal pool, swale, and headwater stream complexes ranges from ~ 20–200, but is ~ 85 when annual precipitation is 100% of normal. Peak stages are evident first in vernal pools which then propagate sequentially downstream through swales, headwater streams, and to the Sacramento River at celerities of ~ 1-1.5 m/s, consistent with expected flood wave velocities. Geospatial analyses show that these vernal pool, swale, and headwater stream features cover > 4% of the study area. Our results suggest these systems can be significant sources of streamflow, and therefore play an important role in maintaining the chemical, physical, and biological integrity of downstream waters, which has important implications for the definition of waters of the United States subject to regulation under the Clean Water Act.
Flexitraits, Natural Chemical Tracers of Plant Competition and Productivity in Pacific MangrovesFry, Brian; O’Mara, Kaitlyn; Riekenberg, Philip M.; Wassenaar, Leonard I.; Cormier, Nicole
doi: 10.1007/s13157-023-01672-9pmid: N/A
Metabolomic and genomic markers in plants have helped diagnose evolutionary pressures and resulting modern-day floristic diversification. Here we use a different set of metrics, 17 biochemical measures made at the whole tissue or bulk tissue level, to study diversification in resource use and productivity among Pacific mangroves. Three mangrove species Bruguiera gynmorhiza (BRGY), Rhizphora apiculata (RHAP), and Sonneratia alba (SOAL) were studied across 5 sites on the island of Kosrae, Federated States of Micronesia with measurements of the following chemical metrics: C, N, P, K, Na, Mg, Ca, B, S, Mn, Fe, Cu, Zn elements and isotope values δ2H, δ13C, δ15N, and δ34S. Species were remarkably distinct in chemical profiles, showing significant differences across all metrics. This indicated long-term resource use partitioning and optimization, with metrics showing physiology and patch-related differences. The patch-related differences meant that metrics were not really fixed in species, but represented flexible traits (“flexitraits”) in fingerprinting mangrove ecology. Effects of tree harvesting could be fingerprinted with the metrics at one of the Kosrae sites. Modeling showed two results. (1) Conservation efforts to preserve low-nutrient specialists like BRGY probably should involve removal of competing SOAL and RHAP rather than nutrient reductions. (2) Although mangrove growth rates were most limited by P, water was a strongly co-limiting factor. This study introduces a new physiological parameter to plant ecology, a water-to-phosphorus ratio, “normalized δ13C/P” or “f13C/P”, that should generally help diagnose how plant N and P nutrient use can be co-limited by water.
Modified, Ecologically Destructed, and Disappeared – History of Urban Wetlands in Helsinki Metropolitan AreaAlikhani, Somayeh; Nummi, Petri; Ojala, Anne
doi: 10.1007/s13157-023-01671-wpmid: N/A
Urban wetlands are one of the important natural resources in cities and have an essential role in the sustainability of the urban environment. They offer various ecosystem services in cities, for example, by mitigating the risk of floods, providing water purification, groundwater regulation, and biodiversity promotion. Urban wetlands also provide recreational opportunities such as swimming and boating, that improve citizens’ well-being. Unfortunately, human activities and environmental factors have been the primary reasons that have destroyed urban wetlands. To identify the main factors which threaten wetlands, as a case study, we investigated the environmental history of six urban wetlands in Helsinki starting from 19th century to the present. We collected historical information from available documents such as research articles, technical reports, maps, and photos, and then we compared the past situation of these urban wetlands with the current conditions throughout history. We also support our statements by referring to urban wetlands with similar conditions from different continents to explain the reasons for wetlands’ disappearance, degradation, or survival. We show that population growth, land-use change, and climate change have been the main threats that have caused the degradation and even the loss of urban wetlands. We discuss the influencing factors which threaten urban wetlands and we highlight the role of policy and decision-makers in the rehabilitation and maintenance of urban wetlands.
Extreme Drought Event Affects Demographic Rates and Functional Groups in Tropical Floodplain Forest PatchesPereira, Kelly Marianne Guimarães; Cordeiro, Natielle Gomes; Santana, Lucas Dezidério; Pyles, Marcela Venelli; Ribeiro, Miriana Araújo; da Silva, Ana Carolina; van den Berg, Eduardo
doi: 10.1007/s13157-023-01673-8pmid: N/A
Floodplains exert restrictions on the development of plants, and the structure and composition of alluvial forests reflect those limitations. We aimed to evaluate how contrasting periods of drought and flooding affect the demographic rates of alluvial forest patches and how these effects are related to forest functional traits and diversity. We studied six alluvial forest fragments in the floodplain along the Sapucaí River in Minas Gerais State, Brazil. We carried out forest inventories in two sequential periods (2005–2011, 2011–2017). We also measured functional traits for species with higher densities and evaluated how the diversity index varied over time. We found that the period with drought (2011–2017) presented higher mortality, higher loss of basal area, and lower recruitment than the period with flood (2005–2011). The alluvial forest responded more intensely and negatively to the impacts of drought (second period) than to the impacts of flooding (first period). Lower diversity plots had higher mortality and basal area loss. We found overall degradation of the alluvial forest with a loss of basal area, a decrease in tree density, and an increase in species with acquisitive functional traits related to a strong drought effect. Thus, increasing extreme events like stronger floods but particularly droughts in function of climate change may be especially pernicious for alluvial forest persistence.
Contribution of Hydrological Connectivity in Maintaining Aquatic Plant Communities in Remnant Floodplain Ponds in Agricultural LandscapesNagata, Yu; Ishiyama, Nobuo; Nakamura, Futoshi; Shibata, Hideaki; Fukuzawa, Karibu; Morimoto, Junko
doi: 10.1007/s13157-023-01684-5pmid: N/A
The expansion of the agricultural landscape has led to the fragmentation of floodplains. These remnant floodplain ponds serve as important habitats for aquatic plants. Hydrological connectivity between floodplain ponds, facilitated by artificial watercourses, plays an important role in providing a migration course for mobile animals, such as fish. However, little is known about the contribution of artificial watercourses to the dispersal of aquatic plants, which are passive dispersers, between floodplain ponds. This study aimed to elucidate the effects of hydrological connectivity through artificial watercourses and environmental factors on the structure and composition of aquatic plant communities in lowland floodplain ponds. Vegetation and environmental surveys of 20 floodplain ponds were conducted in the agricultural landscape of northern Japan. Path analysis was used to clarify the effects of local- and landscape-scale environmental variables on aquatic plant communities with respect to species richness and species coverage. The path analysis results suggested that both hydrological connectivity between floodplain ponds and eutrophication were influential determinants of the species richness of aquatic plant communities. The study findings indicate that water quality management, connectivity conservation, and restoration should be prioritized to maintain aquatic plant communities in degraded floodplain ponds.
Runnels Reverse Mega-pool Expansion and Improve Marsh Resiliency in the Great Marsh, Massachusetts (USA)McKown, J. Grant; Burdick, David M.; Moore, Gregg E.; Peter, Christopher R.; Payne, Andrew R.; Gibson, Jennifer L.
doi: 10.1007/s13157-023-01683-6pmid: N/A
One of the main mechanisms for salt marsh decline across the United States is the inability of the marsh surface to keep pace with sea level rise. The interior platform is especially vulnerable, leading to the encroachment of short form Spartina alterniflora pannes, pool formation, and ultimately runaway pool expansion if recovery is not possible. Coastal ecologists in New England have been implementing a restoration strategy of runnels, or shallow channels, to enhance drainage of oversaturated and ponding interior marshes. In 2015, runnels were constructed to drain two large and expanding pools in the Great Marsh System of Massachusetts, USA. Vegetation, elevation, and hydrology were monitored using field sampling and remote sensing analysis pre- and post-restoration over seven growing seasons to document the trajectory of the pools and adjacent salt marsh platforms. Pool drainage improved reflecting tidal cycles after three years. Substantial colonization of S. alterniflora and S. patens into the previously unvegetated pools required three growing seasons. In the adjacent platform, S. patens and Distichlis spicata increased in abundance with substantial declines in S. alterniflora. The runnel for one pool became blocked by vegetation after three years and inhibited drainage and recovery of the vegetation in the pool yet not the platform. Runnels may be a viable solution for restoring interior marshes following vegetation loss yet substantial improvements in vegetation and hydrology may require 3 – 5 years and complete recovery of the vegetation community in the regularly drained portion of the system for at least a decade.
Reproductive Strategy of the Annual Fish Leptopanchax Opalescens (Rivulidae) and Trade-Off Between Egg Size and Maximum Body Length in Temporary WetlandsGuedes, Gustavo Henrique Soares; Gomes, Iracema David; do Nascimento, Aparecida Alves; de Azevedo, Marcia Cristina Costa; de Araújo Souto-Santos, Igor Cavalcanti; Buckup, Paulo Andreas; Araújo, Francisco Gerson
doi: 10.1007/s13157-023-01680-9pmid: N/A
Leptopanchax opalescens is a critically endangered small annual fish. Reproductive traits of this species were studied to improve our understanding of the strategies that facilitate the occupation of temporary wetlands. We compiled egg diameter and maximum total length data from 136 neotropical killifishes (Rivulidae) to establish comparisons between species with different life histories. We tested the hypothesis that annual killifishes have smaller body sizes and eggs than non-annual killifishes, which may be associated with different life spans and embryonic diapause. Fish were collected from the Guandu River Hydrographic Region (southeastern Brazil). DNA barcoding was employed to confirm the species’ identity. The phases of gonadal development and spawn type were described using histological techniques. Egg size and fecundity were determined. Females with batch spawning and males with continuous spawning were detected. The batch fecundity ranged from 22 to 32 vitellogenic oocytes (mean 27 ± 7 SD). Maximum body size was similar between the two life cycles (p = 0.24), but egg size was smaller for annual killifishes (p < 0.001). Spawning in batches, synchronous modal development of oocytes, continued production of sperm in males, and a complex process of embryonic diapause are reproductive traits that favor the resilience of L. opalescens and other annual fish in temporary wetlands. We conclude that body size is not related to lifespan and that factors underlying the selection of different egg sizes between annual and non-annual killifish species may be associated with different life history strategies to deal with stressful habitats.
On the Topologies of micro/macrohabitats in the Mollusca-Sciomyzidae TaxoceneWilliams, Christopher David
doi: 10.1007/s13157-023-01681-8pmid: N/A
A new perspective on habitat is presented, which considers the topological relationships among macrohabitats of adults and the sub-set microhabitats of eggs and other juvenile stages. A model of seven topologies is presented using the snail-killing flies (Sciomyzidae: Diptera) as an exemplar; four of these topologies are drawn on a hydrological continuum from aquatic through shoreline to terrestrial, and three are presented as stand-alone specialized feeding groups. Colonisation-extinction dynamics are discussed in relation first to macrohabitat dynamics and then microhabitat structure. The topological perspective has wide application outside the Mollusca-Sciomyzidae taxocene e.g. in parasitoid wasp-host taxocenes, in phytophagous insect-host communities, for freshwater macro-invertebrates and even, in the context of a “landscape of fear”, for bird and mammal populations. The perspective taken is more “autecological” than the traditional “biotope” or resource view of habitats, yet is broad enough to encompass many different behavioural groups as shown for the Sciomyzidae.