Dataset Information

Hydroperiod regime controls the organization of plant species in wetlands.

ABSTRACT: With urban, agricultural, and industrial needs growing throughout the past decades, wetland ecosystems have experienced profound changes. Most critically, the biodiversity of wetlands is intimately linked to its hydrologic dynamics, which in turn are being drastically altered by ongoing climate changes. Hydroperiod regimes, e.g., percentage of time a site is inundated, exert critical control in the creation of niches for different plant species in wetlands. However, the spatial signatures of the organization of plant species in wetlands and how the different drivers interact to yield such signatures are unknown. Focusing on Everglades National Park (ENP) in Florida, we show here that cluster sizes of each species follow a power law probability distribution and that such clusters have well-defined fractal characteristics. Moreover, we individuate and model those signatures via the interplay between global forcings arising from the hydroperiod regime and local controls exerted by neighboring vegetation. With power law clustering often associated with systems near critical transitions, our findings are highly relevant for the management of wetland ecosystems. In addition, our results show that changes in climate and land management have a quantifiable predictable impact on the type of vegetation and its spatial organization in wetlands.

SUBMITTER: Foti R

PROVIDER: S-EPMC3511740 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature

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Hydroperiod regime controls the organization of plant species in wetlands.

Foti Romano R del Jesus Manuel M Rinaldo Andrea A Rodriguez-Iturbe Ignacio I

Proceedings of the National Academy of Sciences of the United States of America 20121113 48

With urban, agricultural, and industrial needs growing throughout the past decades, wetland ecosystems have experienced profound changes. Most critically, the biodiversity of wetlands is intimately linked to its hydrologic dynamics, which in turn are being drastically altered by ongoing climate changes. Hydroperiod regimes, e.g., percentage of time a site is inundated, exert critical control in the creation of niches for different plant species in wetlands. However, the spatial signatures of the ...[more]

PMID: 23150589

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Project description:Thoughtfully managed hydroperiods in natural and artificial wetlands could potentially provide a combination of desirable flood control services and high ecological functions. To explore how managed freshwater wetlands typical of the Houston, Texas area would respond to different hydrological regimes that might occur if wetlands were drained in anticipation of a heavy rain that did not materialize, we conducted a mesocosm experiment with six flooding depths and seven drought durations, followed by seven months of recovery. We found that the speed in which mesocosms dried out was a function of initial water depth, with mesocosms initially set with greater water depths (30 cm) taking ~ 38 days to dry out versus zero days for wetlands that were completely drained. Individual plant species (14 species planted; 8 species common at the end of the recovery period) were affected by drought length, flooding depth, or their interaction, although details of these responses varied among the species. The composition of the plant community at the end of the drought period was strongly affected by drought length, and the effect of the drought length treatment persisted through seven months of post-drought recovery, with the 80- and 160-day drought treatments diverging most strongly from shorter drought treatments. Above- and below-ground biomass of plants was not affected by the treatments, but above-ground dead biomass (litter) decreased with increasing drought length. Densities of mosquito larvae, snails and tadpoles were temporally variable, and were affected more during the treatment period and early in recovery than after a disturbance event late in recovery. Our results indicate that managed wetlands in southeast Texas would be quite resilient to dry periods of up to 40 days in duration, especially if water was not completely drained at the beginning of the drought. In addition, many species would persist in managed wetlands even with droughts of up to 160 days. This indicates considerable potential for managing the hydroperiods of artificial detention ponds by retaining water longer to increase ecological function, with little to no loss of flood control services, and for managing the hydroperiods of natural wetlands by draining them in advance of anticipated rains to increase flood control services, with little to no loss of ecological function.

Project description:Oil sands process-affected water (OSPW) is a by-product of bitumen extraction from oil sands surface mining in Alberta, Canada. A major group of organics in OSPW known as naphthenic acid fraction compounds (NAFCs) are of concern due to their persistence and toxicity. Constructed wetland treatment systems have emerged as potential biological treatment approaches for reducing NAFC concentrations within OSPW. In this study, greenhouse-scale mesocosms simulating a constructed wetland consisting of coarse sand tailings (CST) and OSPW were used to evaluate the ability of Scirpus microcarpus, Triglochin maritima, and unplanted controls to attenuate NAFCs under spring/fall and summer temperatures (10°C/5°C and 20°C/10°C day/night). Overall, in this mesocosm system, NAFC attenuation was similar regardless of different design parameters such as plant type, plant presence, and temperature. By the end of the study, NAFCs attenuation was 30% to 50% lower than the initial OSPW depending on plant species, plant presence, and temperature. The relative abundance of the acutely toxic O2-NAFCs decreased over time, with an increase in the less toxic O3, O4, and SO3 classes. Various hydrocarbon-degrading microbial families such as Comamonadaceae and Xanthobacteraceae were found to be dominant in OSPW, while cyanobacteria (Trichormus) were enriched in the CST. Principal component analysis indicated that only time led to distinct clusters for NAFC composition, while plant type, temperature, and time influenced the microbial communities. Shifts in microbial communities over time corresponded to shifts in NAFCs, possibly due to a decrease in toxicity with increased oxidation of NAFCs and/or an increase in available nutrients from a decrease in plant fitness in the planted mesocosms. PRACTITIONER POINTS: Constructed wetland mesocosms for NAFC attenuation from OSPW comparing three planted/unplanted conditions under two temperatures. Mesocosms had 30%-50% removal of total NAFCs, with a decrease in O2-NAFCs and increase in O3, O4, and SO3 classes. NAFC composition only shifted with time, while microbial communities were influenced by plant type, temperature, and time. Lack of difference in NAFC attenuation between treatments could indicate a high level of functional redundancy between the microbial communities.

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Dataset Information

Hydroperiod regime controls the organization of plant species in wetlands.

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Hydroperiod regime controls the organization of plant species in wetlands.

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