TY - JOUR
T1 - Responses of sawgrass and spikerush to variation in hydrologic drivers and salinity in Southern Everglades marshes
AU - Childers, Daniel L.
AU - Iwaniec, David
AU - Rondeau, Damon
AU - Rubio, Gustavo
AU - Verdon, Emilie
AU - Madden, Christopher J.
N1 - Funding Information:
We gratefully acknowledge the field and lab assistance provided by many people to generate these data over the years. Thanks to Gregory Noe for helpful discussions during the development of the ANPP model, and to Jennifer Richards, Chuck Hopkinson, the Wetland Ecosystem Ecology Lab at FIU, and several anonymous reviewers for comments on the manuscript. Permission to access our sites in Everglades National Park was granted through Department of the Interior research permits. This research was supported by the South Florida Water Management District under several sequential contracts, and by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research Program (DEB-9901514). This is contribution #300 of the Southeast Environmental Research Center at Florida International University.
PY - 2006/10
Y1 - 2006/10
N2 - Aboveground net primary production (ANPP) by the dominant macrophyte and plant community composition are related to the changing hydrologic environment and to salinity in the southern Everglades, FL, USA. We present a new non-destructive ANPP technique that is applicable to any continuously growing herbaceous system. Data from 16 sites, collected from 1998 to 2004, were used to investigate how hydrology and salinity controlled sawgrass (Cladium jamaicense Crantz.) ANPP. Sawgrass live biomass showed little seasonal variation and annual means ranged from 89 to 639 gdw m-2. Mortality rates were 20-35% of live biomass per 2 month sampling interval, for biomass turnover rates of 1.3-2.5 per year. Production by C. jamaicense was manifest primarily as biomass turnover, not as biomass accumulation. Rates typically ranged from 300 to 750 gdw m-2 year-1, but exceeded 1000 gdw m-2 year-1 at one site and were as high as 750 gdw m-2 year-1 at estuarine ecotone sites. Production was negatively related to mean annual water depth, hydroperiod, and to a variable combining the two (depth-days). As water depths and hydroperiods increased in our southern Everglades study area, sawgrass ANPP declined. Because a primary restoration goal is to increase water depths and hydroperiods for some regions of the Everglades, we investigated how the plant community responded to this decline in sawgrass ANPP. Spikerush (Eleocharis sp.) was the next most prominent component of this community at our sites, and 39% of the variability in sawgrass ANPP was explained by a negative relationship with mean annual water depth, hydroperiod, and Eleocharis sp. density the following year. Sawgrass ANPP at estuarine ecotone sites responded negatively to salinity, and rates of production were slow to recover after high salinity years. Our results suggest that ecologists, managers, and the public should not necessarily interpret a decline in sawgrass that may result from hydrologic restoration as a negative phenomenon.
AB - Aboveground net primary production (ANPP) by the dominant macrophyte and plant community composition are related to the changing hydrologic environment and to salinity in the southern Everglades, FL, USA. We present a new non-destructive ANPP technique that is applicable to any continuously growing herbaceous system. Data from 16 sites, collected from 1998 to 2004, were used to investigate how hydrology and salinity controlled sawgrass (Cladium jamaicense Crantz.) ANPP. Sawgrass live biomass showed little seasonal variation and annual means ranged from 89 to 639 gdw m-2. Mortality rates were 20-35% of live biomass per 2 month sampling interval, for biomass turnover rates of 1.3-2.5 per year. Production by C. jamaicense was manifest primarily as biomass turnover, not as biomass accumulation. Rates typically ranged from 300 to 750 gdw m-2 year-1, but exceeded 1000 gdw m-2 year-1 at one site and were as high as 750 gdw m-2 year-1 at estuarine ecotone sites. Production was negatively related to mean annual water depth, hydroperiod, and to a variable combining the two (depth-days). As water depths and hydroperiods increased in our southern Everglades study area, sawgrass ANPP declined. Because a primary restoration goal is to increase water depths and hydroperiods for some regions of the Everglades, we investigated how the plant community responded to this decline in sawgrass ANPP. Spikerush (Eleocharis sp.) was the next most prominent component of this community at our sites, and 39% of the variability in sawgrass ANPP was explained by a negative relationship with mean annual water depth, hydroperiod, and Eleocharis sp. density the following year. Sawgrass ANPP at estuarine ecotone sites responded negatively to salinity, and rates of production were slow to recover after high salinity years. Our results suggest that ecologists, managers, and the public should not necessarily interpret a decline in sawgrass that may result from hydrologic restoration as a negative phenomenon.
KW - ANPP
KW - Everglades
KW - Hydrology
KW - LTER
KW - Restoration
KW - Sawgrass
UR - http://www.scopus.com/inward/record.url?scp=33746689688&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33746689688&partnerID=8YFLogxK
U2 - 10.1007/s10750-006-0137-9
DO - 10.1007/s10750-006-0137-9
M3 - Article
AN - SCOPUS:33746689688
SN - 0018-8158
VL - 569
SP - 273
EP - 292
JO - Hydrobiologia
JF - Hydrobiologia
IS - 1
ER -