Elizabeth H. Boughton

Trade-Offs Among Ecosystem Services and Disservices on a Florida Ranch

On the Ground We consider the trade-offs among “good” ecosystem services and “bad” ecosystem disservices attributable to past and current ranchland management and how such trade-offs depend on analysis at the scale of the ranch, the region, or the Earth. We focus on trade-offs in ecosystem services at one working ranch—Buck Island Ranch, location of the MacArthur Agro-ecology Research Center, lying in the headwaters of Floridas Everglades—and managed for 25 years as a full-scale cow–calf operation by Archbold Biological Station, one of the worlds preeminent ecological research centers. The synthesis of how this ranch functions as an ecosystem (species, habitats, nutrient dynamics, hydrology, etc.) is set in the context of financial realities and economic viability. We develop a conceptual model to visualize trade-offs among ecosystem services and disservices, and provide insight into what it takes to be sustainable ecologically and economically.

Modification by an invasive ecosystem engineer shifts a wet prairie to a monotypic stand

At the landscape scale, ecosystem engineers are expected to increase species diversity; however, diversity could decline if the ecosystem engineer is over-abundant. Thus, invasive ecosystem engineers are expected to have strong impacts, due to their high abundances and novel disturbances. An invasive ecosystem engineer, the feral swine (Sus scrofa), is a species that creates intense soil disturbances, altering soil and plant communities. In this study, we examine the effects of this invasive ecosystem engineer on experimental plant plots that had been protected for over a decade. Feral swine avoided recently burned plots and preferred plots with N addition. Rooted plots shifted from a bunchgrass dominated wet prairie to a monotypic stand of the native, Lachnanthes caroliana. Feral swine were also attracted to plots with existing patches of L. caroliana suggesting a potential positive feedback between swine activity and L. caroliana patch expansion that could result in an alternative state.

Interactive effects of pasture management intensity, release from grazing and prescribed fire on forty subtropical wetland plant assemblages

Summary 1. Pasture management intensity, livestock grazing and prescribed fire are three widespread agricultural practices that affect small, isolated wetlands, but few studies have investigated their individual and interactive effects. Pasture management intensity refers to the degree of human alteration of grassland, ranging from intensively managed pastures planted with introduced forage, fertilizer/lime additions and artificial drainage to semi-natural pastures with mixed native and non-native vegetation, no fertilizer/lime additions and little or no artificial drainage. 2. We examined individual and interactive effects of these three agricultural practices on individual, isolated wetlands using a replicated, full-factorial experiment on 40 entire wetlands in south Florida, USA. Wetlands were embedded in two pasture management intensities: intensively managed and semi-natural. 3. After three years of treatment initiation, vegetation of wetlands released from grazing and unburned embedded in semi-natural pastures had significantly lower evenness and coefficient of conservatism scores compared to wetlands released from grazing and burned, grazed unburned wetlands and grazed burned wetlands in the same pasture management intensity. For wetlands embedded in intensively managed pastures, evenness and coefficient of conservatism scores did not differ among treatments. 4. Release from grazing increased abundance of the native, weedy herb, Eupatorium capillifolium. 5. Grazing interacted with prescribed fire to affect shrub abundance and non-native richness; relative abundance of shrubs and non-native richness were greater in wetlands released from grazing and burned and did not differ among burn treatments in grazed wetlands. Interactive effects, especially three-way interactions, were uncommon and not as important as differences between the two pasture management intensities. 6. Synthesis and applications. Vegetation diversity and floristic quality of wetlands embedded in intensively managed pastures resisted common restoration management techniques such as release from grazing and prescribed fire, at least in the short term. In contrast, removing all top-down disturbances from wetlands embedded in semi-natural grasslands can negatively affect vegetation species diversity and floristic quality. Future studies should examine how intensity and seasonality of grazing and prescribed fire affect wetland vegetation, and track long-term responses to evaluate lag effects.

Dispersal and local environment affect the spread of an invasive apple snail (Pomacea maculata) in Florida, USA

Dispersal and local environmental factors are major determinants of invasive species distribution. We examined how both dispersal-related geospatial characteristics and environmental factors influence an ongoing invasion of wetlands in a south-central Florida ranchland by non-native apple snails (Pomacea maculata, Ampullariidae). We found P. maculata in 73 (43%) of a random set of 171 wetlands in 2014. We used model selection to evaluate multiple hypotheses of predictors of P. maculata occurrence in 95 wetlands with standing water, including spatially-explicit distances in ditches from wetlands to the presumed entry point, Euclidean (overland) distances, presence/absence of ditches in wetlands, and environmental variables (e.g. pH). We also performed a 5-month field experiment in 20 wetlands to evaluate if snail absence was associated with conditions that limit survival and growth (i.e. unfavorable habitats). Snail occurrence was primarily associated with presence of ditches in wetlands and more neutral wetland pH. These variables more plausibly explained snail occurrence than did Euclidean (overland) distance and minimum ditch travel (rectilinear) distance from propagule sources (a major waterway). Wetland pH best explained survival and growth under the experimental conditions. We found no evidence that prior occupancy by conspecifics affected survival and growth, suggesting that dispersal limitation may contribute to lack of occupancy of wetlands, despite suitable pH. Our study supports man-made conduits as facilitators of dispersal by non-native species, where environmental characteristics (here pH) then also affect colonization within habitats. An understanding of both dispersal mechanisms and local environmental factors is necessary to better predict invasive species distribution.

Reproductive traits of Lachnanthes caroliniana (Lam.) Dandy related to patch formation following feral swine rooting disturbance1

Abstract Understanding plant reproductive traits is important to discerning underlying mechanisms of patch formation by clonal plants after soil disturbance. Reproductive traits that are likely important to patch formation include regeneration ability of rhizomes, seed production and long-term germination ability, and seed presence in the seedbank. In this study, reproductive traits of the clonal plant Lachnanthes caroliniana (Lam.) Dandy that were dominating patches disturbed by feral swine were assessed. The study assessed the ability of rhizomes to resprout in relation to rhizome size (10 cm to 20 cm or 20 cm to 30 cm) and burial depth (buried or surficial). Field surveys were conducted in monocultures to measure the density of inflorescences and seed production. A seed germination and longevity growth chamber experiment was conducted to test the effect of moist or submersed conditions. Finally, a seed bank assay measured the field germination ability of L. caroliniana. Rhizomes had, on average, 81% survival rate and 100% buried rhizomes; rhizome size did not affect survival. Seed production was high with 126,579 seeds per m2, but in the growth chamber germination was low (0.5%) and short-lived, with nearly all germinates occurring by 51 days and one germinant at 129 days. Only one seedling of L. caroliniana germinated from the seed bank of soil collected prior to the current years seed rain, also supporting a short-lived seed bank, as suggested by the timeline of the seed germination study results. These results suggest that reproductive traits of rhizome resprouting and high production of seeds (approx. 600 germinants per m2) may give this species a competitive advantage to form dense patches following feral swine rooting disturbance. Since feral swine continuously return to patches of L. caroliniana, it is likely that this plant and other disturbance-adapted clonal species could increase at the landscape scale as feral swine populations continue to rapidly expand.

Acquiring Water Services From Northern Everglades Ranchlands

On the Ground The Northern Everglades Payment for Environmental Services (NE-PES) Program implemented by the South Florida Water Management District (SFWMD) is a unique example of an operating market-like payment for environmental services program on working ranchlands. The SFWMD enters into 10-year contracts to pay ranchers who dedicate parts of their ranch to providing water retention or nutrient removal services. NE-PES monitoring procedures were designed to assure that water was managed as agreed to in the contracts and annual payments only were made if contract terms were honored. Key challenges to the design of monitoring procedures were that the protocol must 1) satisfy the buyer that they were getting the services they paid for, 2) assure the sellers that the services they provide are being fairly assessed, and 3) be feasible to administer over a large number of ranches in an expansive working agricultural landscape.October 2013 88 Rangelands In January of 2011, South Florida Water Management District (SFWMD) issued a solicitation under the Northern Everglades Payment for Environmental Services (NE-PES) Program.1 The solicitation asked cattle ranchers to propose on-ranch water management practices to retain water and slow runoff toward Lake Okeechobee—a water retention service—or propose how they might remove nutrients from off-ranch water before that water reached the lake—a nutrient removal service. In responding to the solicitation, the ranchers requested the payment that would make them willing to provide these services during a 10-year contract period. The SFWMD reviewed the responses to the solicitation and, after negotiating with the ranchers, chose to enter into contracts with eight ranchers. A second solicitation was issued in winter 2013. Twenty proposals were submitted and a final selection of contracts is expected in late summer 2013. Environmental services such as improved water quality, wildlife habitat, carbon sequestration, and hydrologic flow modification can be provided from working ranchlands.2 Payment for Environmental Services (PES) programs seek to increase the level of such services, above what would be provided by these lands in the future. Equally important, PES can support the financial viability of cattle ranching, a land use compatible with conservation objectives but one with low profit margins. For these reasons PES programs on ranchlands are advocated with increasing frequency.3 In fact, the NE-PES program is a unique example of an operating PES program built on market-like principles. The distinguishing feature that makes NE-PES market-like is that payments only are made if the services are provided. This makes the NE-PES different from programs that only pay a share of the cost for the installation of best management practices. The link between realized services and the payment requires a monitoring protocol for documenting service provision. However, that monitoring protocol must be feasible to administer across large landscapes, given inevitable limits on the monitoring budget. Of course the protocol must satisfy the buyers that they are getting the services they pay for and assure the sellers that the services they provide are being fairly assessed. For this reason it is noteworthy that while the NE-PES payment only is made if the buyer believes that the service is provided, the monitoring protocol does not directly measure the service level. Therefore, before describing the NE-PES protocol we first introduce the collaborative process that led up to the NE-PES in order to explain how the SFWMD (buyer) and the rancher (sellers) agreed on a protocol that was not based on directly measuring the service. Acquiring Water Services From Northern Everglades Ranchlands

From Dusty Trails to Waning Wetlands – 67th SRM Annual Meeting & Trade ShowAcquiring Water Services From Northern Everglades Ranchlands: Assuring buyers that they get what they paid for

On the Ground The Northern Everglades Payment for Environmental Services (NE-PES) Program implemented by the South Florida Water Management District (SFWMD) is a unique example of an operating market-like payment for environmental services program on working ranchlands. The SFWMD enters into 10-year contracts to pay ranchers who dedicate parts of their ranch to providing water retention or nutrient removal services. NE-PES monitoring procedures were designed to assure that water was managed as agreed to in the contracts and annual payments only were made if contract terms were honored. Key challenges to the design of monitoring procedures were that the protocol must 1) satisfy the buyer that they were getting the services they paid for, 2) assure the sellers that the services they provide are being fairly assessed, and 3) be feasible to administer over a large number of ranches in an expansive working agricultural landscape.October 2013 88 Rangelands In January of 2011, South Florida Water Management District (SFWMD) issued a solicitation under the Northern Everglades Payment for Environmental Services (NE-PES) Program.1 The solicitation asked cattle ranchers to propose on-ranch water management practices to retain water and slow runoff toward Lake Okeechobee—a water retention service—or propose how they might remove nutrients from off-ranch water before that water reached the lake—a nutrient removal service. In responding to the solicitation, the ranchers requested the payment that would make them willing to provide these services during a 10-year contract period. The SFWMD reviewed the responses to the solicitation and, after negotiating with the ranchers, chose to enter into contracts with eight ranchers. A second solicitation was issued in winter 2013. Twenty proposals were submitted and a final selection of contracts is expected in late summer 2013. Environmental services such as improved water quality, wildlife habitat, carbon sequestration, and hydrologic flow modification can be provided from working ranchlands.2 Payment for Environmental Services (PES) programs seek to increase the level of such services, above what would be provided by these lands in the future. Equally important, PES can support the financial viability of cattle ranching, a land use compatible with conservation objectives but one with low profit margins. For these reasons PES programs on ranchlands are advocated with increasing frequency.3 In fact, the NE-PES program is a unique example of an operating PES program built on market-like principles. The distinguishing feature that makes NE-PES market-like is that payments only are made if the services are provided. This makes the NE-PES different from programs that only pay a share of the cost for the installation of best management practices. The link between realized services and the payment requires a monitoring protocol for documenting service provision. However, that monitoring protocol must be feasible to administer across large landscapes, given inevitable limits on the monitoring budget. Of course the protocol must satisfy the buyers that they are getting the services they pay for and assure the sellers that the services they provide are being fairly assessed. For this reason it is noteworthy that while the NE-PES payment only is made if the buyer believes that the service is provided, the monitoring protocol does not directly measure the service level. Therefore, before describing the NE-PES protocol we first introduce the collaborative process that led up to the NE-PES in order to explain how the SFWMD (buyer) and the rancher (sellers) agreed on a protocol that was not based on directly measuring the service. Acquiring Water Services From Northern Everglades Ranchlands

Assessing the success of hydrological restoration in two conservation easements within Central Florida ranchland

In the USA, the United States Department of Agriculture (USDA) Natural Resource Conservation Service (NRCS) has restored millions of acres of wetlands through its Wetland Reserve Easement (WRE) programs. However, few quantitative studies have explored whether WREs have enhanced wetland hydrology and wetland plant communities. Additionally, USDA Compatible Use Permits for cattle grazing and other management practices are sometimes issued for WREs, but little is known about potential benefits/detriments of such practice on the success of wetland restoration. In this study, we tested if hydrological restoration of previously drained species poor pastures increased water depth and hydroperiod. Restoration involved plugging key ditches, adding water control structures and a berm. We also tested if hydrological restoration increased plant diversity (alpha and beta), floristic quality (using coefficient of conservatism) and increased the cover of wetland species (using species wetland status). Finally, we tested if cattle grazing had an effect on the success of restoration by comparing grazed plots to fenced plots. We studied two conservation easements (a total of 748 acres) located on semi-native pastures in central Florida, USA. We monitored vegetation using permanent transects stratified by vegetation type before (2004–2005) and after (2012) the restoration (2008). We assessed wetland hydroperiod using groundwater wells set up in 2003 and located within and outside the boundaries of these two easements. We used linear mixed models and multivariate analyses to compare vegetation and hydroperiods pre- and post-restoration. Number of flooded days increased following restoration in one of the easements, but we did not detect significant changes in hydrology in the other easement. Floristic quality, beta diversity and cover of obligate wetland species increased in both conservation easements and in most vegetation types. These vegetation changes were likely due to restoration activities since annual rainfall was not significantly different pre- and post-restoration. Cattle grazing did not have a negative or positive effect on the success of restoration, nor did we detect any positive effect of grazing on the success of restoration. Overall, our study shows that hydrological restoration can enhance wetland hydroperiod, water depth and wetland vegetation, but more resources should be allocated to short- and long-term monitoring of the restoration success.

Effects of experimental season of prescribed fire and nutrient addition on structure and function of previously grazed grassland

Aims Understanding the drivers of grassland structure and function following livestock removal will inform grassland restoration and management. Here, we investigated the effects of fire and nutrient addition on structure and function in a subtropical semi-native grassland recently released from grazing in south-central Florida. We examined responses of soil nutrients, plant tissue nutrients, biomass of live, standing dead and litter, and plant species composition to experimental annual prescribed fire applied during different seasons (wet season vs. dry season), and nutrient additions (N, P and N + P) over 9 years. Methods Experimental plots were set up in a randomized block split-plot design, with season of prescribed fire as the main treatment and nutrient addition as the subplot treatment. Species cover data were collected annually from 2002 to 2011 and plant tissue and plant biomass data were collected in 2002–2006 and 2011. Soil nutrients were analyzed in 2004, 2006 and 2011. Important Findings Soil total phosphorus (P) levels increased substantially with P addition but were not influenced by prescribed fire. Addition of P and N led to increased P and N concentrations in live plant tissues, but prescribed fire reduced N in live tissue. Levels of tissue N were higher in all plots at the beginning of the experiment, an effect that was likely due to grazing activity prior to removal of livestock. Plant tissue N steadily declined over time in all plots, with annually burned plots declining faster than unburned plots. Prescribed fire was an important driver of standing dead and litter biomass and was important for maintaining grass biomass and percent cover. Nutrient addition was also important: the addition of both N and P was associated with greater live biomass and woody forbs. Removal of grazing, lack of prescribed fire, and addition of N + P led to a reduction of grass biomass and a large increase in biomass of a woody forb. Annual prescribed fire promoted N loss from the system by reducing standing dead and litter, but maintained desirable biomass of grasses.