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Questions: Grasslands provide important provisioning services worldwide and their management has consequences for these services. Management intensification is a widespread land‐use change and has accelerated across North America to meet rising demands on productivity, yet its impact on the relationship between plant diversity and productivity is still unclear. Here, we investigated the relationship between plant diversity and grassland productivity across nine ecoclimatic domains of the continental United States. We also tested the effect of management intensification on diversity and productivity in four case studies. Methods: We acquired remotely sensed gross primary productivity data (GPP, 1986–2018) and plant diversity data measured at different spatial scales (1, 10, 100, 400 m2), as well as climate variables including the Palmer drought index from two ecological networks. We used general linear mixed models to relate GPP to plant diversity across sites. For the case study analysis, we used linear mixed models to relate plant diversity to management intensity, and tested if the management intensity influenced the relationship between GPP (mean and temporal variation) and drought. Results: Across all sites, we observed positive relationships among species richness, productivity, and the temporal stability of mean annual biomass production. These relationships were not affected by the scale at which species richness was observed. In three out of the four case studies, we observed that management effects on species richness were only significant at broader scales (i.e., ≥10 m2) with no clear effect found at the commonly used 1‐m2 quadrat scale. In one case study, species‐poor, intensively managed pastures presented the highest productivity but were more sensitive to dry conditions than less intensified pastures. However, in other case studies, we did not observe significant effects of management intensity on the magnitude or stability of productivity. Conclusions: Generalization across studies may be difficult and require the development of intensification indices general enough to be applied across diverse management strategies in grazilands. Understanding how management intensification affects grassland productivity will inform the development of sustainable intensification strategies. [ABSTRACT FROM AUTHOR]

Biodiversity impacts are rarely included in systems analyses of livestock production. We piloted two approaches toward quantifying biodiversity impacts, pressure‐state‐response (PSR) and potential species loss (PSL), at a cow–calf operation in Florida for which extensive environmental data were available. Using these approaches, we compared livestock production on two vegetation types, semi‐native pasture (SNP) and improved pasture (IMP), and we found fewer deleterious effects on biodiversity associated with SNP (characterized by low stocking rates and no fertilizer) than with IMP, as evidenced by a lower PSL and greater biotic integrity under PSR. Both approaches agreed in the direction of the outcome, but we argue that, when possible, they should be applied complementarily to inform both absolute and per‐unit product biodiversity impacts of livestock production. This research demonstrates how to incorporate biodiversity into life‐cycle perspectives of livestock sustainability assessments when data availability varies, supporting the expansion of multi‐metric, holistic evaluations that are absent from most livestock system analyses. [ABSTRACT FROM AUTHOR]

Seasonally inundated wetlands are threatened ecosystems worldwide and increasingly important targets for wetland restoration programs. However, restoring such ecosystems is difficult, as it requires mimicking the historical shifts between dry and flooded states. In this study, we evaluate the responses of agriculturally impacted seasonal wetlands to pasture-scale hydrological restoration. We selected 15 seasonal wetlands in central Florida (10 within restoration easements and five in unrestored pastures) and excluded cattle from five of the restored wetlands. We monitored each wetland from 2011 to 2016 to document potential changes in water levels, plant species richness, beta diversity, floristic quality, and cover of obligate wetland species. Vegetation responses to restoration were gradual and subtle, becoming detectable only five years following restoration. By 2016, restored wetlands had significantly lower cover of facultative upland species and higher cover of obligate wetland species. Species richness was higher in unrestored wetlands due to the presence of many facultative upland species. Beta diversity within wetlands and floristic quality based on coefficient of conservatism were not affected by restoration. We did not find strong effects of cattle exclusion on post-restoration diversity metrics, but we observed a large increase in the native grass, Panicum hemitomon Schult. This study showed mixed outcomes when measured against the goals of restoring wetland communities. It also highlighted the need for more active restoration approaches to regain historical communities or promote target species (e.g. Coleataenia abscissa (Swallen) LeBlond). We emphasize the need for costly restoration activities to be coupled with long-term monitoring to assess success. [ABSTRACT FROM AUTHOR]

Isolated, seasonal wetlands within agricultural landscapes are important ecosystems. However, they are currently experiencing direct and indirect effects of agricultural management surrounding them. Because wetlands provide important ecosystem services, it is crucial to determine how these factors affect ecological communities. Here, we studied the long‐term effects of land‐use intensification, cattle grazing, prescribed fires, and their interactions on wetland plant diversity, community dynamics, and functional diversity. To do this, we used vegetation and trait data from a 14‐year‐old experiment on 40 seasonal wetlands located within seminatural and intensively managed pastures in Florida. These wetlands were allocated different grazing and prescribed fire treatments (grazed vs. ungrazed, burned vs. unburned). Our results showed that wetlands within intensively managed pastures have lower native plant diversity, floristic quality, evenness, and higher nonnative species diversity and exhibited the most resource‐acquisitive traits. Wetlands embedded in intensively managed pastures were also characterized by lower species turnover over time. We found that 14 years of cattle exclusion reduced species diversity in both pasture management intensities and had no effect on floristic quality. Fenced wetlands exhibited lower functional diversity and experienced a higher rate of community change, both due to an increase in tall, clonal, and palatable grasses. The effects of prescribed fires were often dependent on grazing treatment. For instance, prescribed fires increased functional diversity in fenced wetlands but not in grazed wetlands. Our study suggests that cattle exclusion and prescribed fires are not enough to restore wetlands in intensively managed pastures and further highlights the importance of not converting seminatural pastures to intensively managed pastures. Our study also suggests that grazing levels applied in seminatural pastures maintained high plant diversity and prevented tree and shrub encroachment and that in the absence of grazing, prescribed fire became crucial to maintaining higher species evenness. [ABSTRACT FROM AUTHOR]

Evapotranspiration (ET) constitutes the largest loss of water from subtropical grassland and wetland ecosystems, yet data in much of the world have high uncertainty at the landscape scale as there is little information on plant water use. Additionally, anthropogenic alterations to grasslands are a major threat globally and alter ecosystem water use, but the impact of these changes is often unquantified. A major reason for this is the complexity and expense of field‐based ET quantification methods such as agricultural lysimeters and eddy covariance systems. Accurate measurements of ET are critical for sustainable water management. This study developed two different low‐cost lysimeters—weighing‐type and water level‐based, to measure ET under partly controlled conditions for single species as well as mixed grassland and wetland communities. Lysimeters were placed in an open‐sided, transparent‐roofed shadehouse and watered periodically. ET values were then compared with (i) actual ET from an eddy covariance tower onsite, (ii) vapour transport‐based reference ET models (FAO Penman–Monteith, modified Turc and Abtew simple radiation models), and (iii) reference ET data customized for vegetation types from the Florida Automated Weather Network (FAWN). Both weighing‐type and water level lysimeters yielded seasonal patterns and annual magnitudes similar to other ET methods. Annual ET measurements from single‐species weighing‐type lysimeters (ranging from 881 to 1278 mm for four plant species, n = 5 per species, 20 in total) and water level lysimeters (1085 ± 306 mm, plant community average, n = 31) were about 10–20% lower than reference ET models (~1300 mm) and similar to FAWN data (1050 mm). Actual ET from eddy covariance was 722 mm for 10 months (missing data for February and March), while weighing lysimeter measurements for the dominant grass Paspalum notatum was 885 mm for the same 10 months. While rainfall exclusion and watering can result in ET differing from actual field conditions, low‐cost lysimeters can provide an independent measure of ET for comparison with regional ET models/remote sensing data lacking field validation. Thereby, low‐cost lysimeters are potentially useful for water resources and ecosystem management in data‐poor regions of the world. [ABSTRACT FROM AUTHOR]

Biotic and abiotic factors interact with dominant plants—the locally most frequent or with the largest coverage—and nondominant plants differently, partially because dominant plants modify the environment where nondominant plants grow. For instance, if dominant plants compete strongly, they will deplete most resources, forcing nondominant plants into a narrower niche space. Conversely, if dominant plants are constrained by the environment, they might not exhaust available resources but instead may ameliorate environmental stressors that usually limit nondominants. Hence, the nature of interactions among nondominant species could be modified by dominant species. Furthermore, these differences could translate into a disparity in the phylogenetic relatedness among dominants compared to the relatedness among nondominants. By estimating phylogenetic dispersion in 78 grasslands across five continents, we found that dominant species were clustered (e.g., co‐dominant grasses), suggesting dominant species are likely organized by environmental filtering, and that nondominant species were either randomly assembled or overdispersed. Traits showed similar trends for those sites (<50%) with sufficient trait data. Furthermore, several lineages scattered in the phylogeny had more nondominant species than expected at random, suggesting that traits common in nondominants are phylogenetically conserved and have evolved multiple times. We also explored environmental drivers of the dominant/nondominant disparity. We found different assembly patterns for dominants and nondominants, consistent with asymmetries in assembly mechanisms. Among the different postulated mechanisms, our results suggest two complementary hypotheses seldom explored: (1) Nondominant species include lineages adapted to thrive in the environment generated by dominant species. (2) Even when dominant species reduce resources to nondominant ones, dominant species could have a stronger positive effect on some nondominants by ameliorating environmental stressors affecting them, than by depleting resources and increasing the environmental stress to those nondominants. These results show that the dominant/nondominant asymmetry has ecological and evolutionary consequences fundamental to understand plant communities. [ABSTRACT FROM AUTHOR]

Fertilisation experiments have demonstrated that nutrient availability is a key determinant of biomass production and carbon sequestration in grasslands. However, the influence of nutrients in explaining spatial variation in grassland biomass production has rarely been assessed. Using a global dataset comprising 72 sites on six continents, we investigated which of 16 soil factors that shape nutrient availability associate most strongly with variation in grassland aboveground biomass. Climate and N deposition were also considered. Based on theory‐driven structural equation modelling, we found that soil micronutrients (particularly Zn and Fe) were important predictors of biomass and, together with soil physicochemical properties and C:N, they explained more unique variation (32%) than climate and N deposition (24%). However, the association between micronutrients and biomass was absent in grasslands limited by NP. These results highlight soil properties as key predictors of global grassland biomass production and point to serial co‐limitation by NP and micronutrients. [ABSTRACT FROM AUTHOR]

Increasing demand for agricultural products is driving grassland management intensification with subsequent impacts on ecosystem services and disservices. Key questions related to grassland production as well as environmental and social concerns must be addressed to ensure sustainability. We propose a unified perspective, addressing numerous trade‐offs and synergies between grassland ecosystem services and disservices, and considering an array of ecological and human consequences associated with history and ongoing shifts in management strategies. Much of our discussion utilizes evidence from humid grasslands; however, our examples and recommendations have global implications for the future of grassland management. We characterize four categories of ecosystem services and disservices (provisioning, supporting, regulating, and cultural) provided by perennial grasslands that are extensively managed (low or no input, never cultivated) or intensively managed (high‐input, cultivated). We explore a range of potential outcomes following transition from extensive to intensive agroecosystems around the globe. Additionally, we suggest specific research priorities to better evaluate ecosystem services and disservices across management intensities. Finally, we highlight potential benefits of landscape mosaics that include grasslands across a continuum of extensive to intensive strategies. [ABSTRACT FROM AUTHOR]

The effects of altered nutrient supplies and herbivore density on species diversity vary with spatial scale, because coexistence mechanisms are scale dependent. This scale dependence may alter the shape of the species–area relationship (SAR), which can be described by changes in species richness (S) as a power function of the sample area (A): S = cAz, where c and z are constants. We analysed the effects of experimental manipulations of nutrient supply and herbivore density on species richness across a range of scales (0.01–75 m2) at 30 grasslands in 10 countries. We found that nutrient addition reduced the number of species that could co‐occur locally, indicated by the SAR intercepts (log c), but did not affect the SAR slopes (z). As a result, proportional species loss due to nutrient enrichment was largely unchanged across sampling scales, whereas total species loss increased over threefold across our range of sampling scales. [ABSTRACT FROM AUTHOR]

Global change is impacting plant community composition, but the mechanisms underlying these changes are unclear. Using a dataset of 58 global change experiments, we tested the five fundamental mechanisms of community change: changes in evenness and richness, reordering, species gains and losses. We found 71% of communities were impacted by global change treatments, and 88% of communities that were exposed to two or more global change drivers were impacted. Further, all mechanisms of change were equally likely to be affected by global change treatments—species losses and changes in richness were just as common as species gains and reordering. We also found no evidence of a progression of community changes, for example, reordering and changes in evenness did not precede species gains and losses. We demonstrate that all processes underlying plant community composition changes are equally affected by treatments and often occur simultaneously, necessitating a wholistic approach to quantifying community changes. [ABSTRACT FROM AUTHOR]

Aims: The stress gradient hypothesis predicts that competition will be important in productive environments while facilitation will be common in environments with high stress or consumer pressure. However, abiotic stress and grazing may vary independently and even occur simultaneously. Here we examine the outcome of plant interactions in grazed wetlands where consumer pressure and abiotic stress occur concurrently. We hypothesized that cattle grazing and microhabitat would alter the outcome of plant interactions. Given that wetland edges are drier and less productive than wetland centers we expected that facilitation would be greatest in drier wetland edges due to greater abiotic stress regardless of cattle presence. Location: Archbold Biological Station's Buck Island Ranch (BIR), south‐central Florida, USA (27°09′ N, 81°11′ W). Methods: We conducted an experiment for two growing seasons in ten wetlands, five exposed to cattle grazing and five fenced. Two wetland obligate plants were included (Panicum hemitomon and Alternanthera philoxeroides), and plots were assigned to three treatments (a) all neighbors removed; (b) all neighbors removed except Juncus effusus, a dominant, unpalatable plant; and (c) all neighbors intact (control), in both wetland centers and edges. Differences in survival, change in height and number of leaves were assessed. Results: In ungrazed wetlands, plant survival was higher in wetland edges vs centers, while it did not differ between microhabitats in grazed wetlands. Survival in wetland edges was further increased by the presence of Juncus effusus. Positive interactions under grazed conditions were clear when plant height was assessed, but negative interactions affected leaf production in both ungrazed and grazed wetlands. Conclusions: Grazing interacts with wetland microhabitat to alter plant survival. Facilitative interactions on plant height were apparent in grazed wetlands. Understanding how plant interactions change under different biotic and abiotic contexts is important for informing ecosystem restoration and management. [ABSTRACT FROM AUTHOR]

Wetlands in agroecosystems provide multiple ecosystem services, including provisioning services such as forage production. Here, we examine how pasture management intensity (semi‐natural pastures vs. highly managed pastures (fertilized, heavily drained, planted with productive grasses), cattle exclusion (grazed vs. fenced), prescribed fire (burned vs. unburned), and their interactions affect provisioning services provided by small, isolated, and seasonally flooded wetlands in subtropical pastures and rangelands. We used a replicated, full‐factorial experiment on 40 seasonally flooded wetlands located in Florida (USA), and measured standing plant biomass and annual net primary productivity in each wetland. Biomass was sorted by species to calculate species abundance of palatable and unpalatable plants. We used general linear mixed models to evaluate the effect of treatments and their interactions on biomass quantity, plant tissue nutrients (% C, % N, and % P), and forage nutritive value (using in vitro organic matter digestibility). Plant standing biomass and productivity were greatest in wetlands embedded in highly managed pastures, but in grazed wetlands, a large proportion of this biomass was unpalatable to cattle. Excluding cattle from wetlands in highly managed pastures increased productivity, standing biomass, and the amount of palatable species (~6.3 t/ha) compared to grazed wetlands (~3.3 t/ha), especially when these wetlands were also exposed to prescribed fire. Total P in plant tissue was consistently higher in wetlands within highly managed pastures, but total N responses to treatments varied between years. In vitro digestibility was higher in vegetation from wetlands within highly managed pastures, but not in fenced wetlands despite the higher amount of palatable species, suggesting that palatability and digestibility were decoupled. Subtropical wetlands in agroecosystems provide substantial provisioning services, and our study suggests that targeted management can increase these services. However, the pasture type surrounding a wetland interacts with grazing and fire management to affect provisioning services. We propose that fencing off selected wetlands (specifically in highly managed pastures) followed by low‐intensity grazing with adequate resting periods could benefit ranchers and have less persistent impacts on this ecosystem. [ABSTRACT FROM AUTHOR]

The article presents a study which examined the environmental drivers affecting carbon dioxide (CO2) and methane (CH4) fluxes in temporary flooded subtropical wetlands. Also cited are the relationship between gross primary productivity (GPP) with radiation and temperature, the reasons behind soil inundation, and the role of subtropical and tropical wetlands in the global carbon (C) cycle.

Wetlands are an important source of CH4 globally. However, uncertainty surrounding the impact of anthropogenic activities on CH4 emissions from wetlands limits understanding of how these ecosystems will respond to management changes. Furthermore, by neglecting the potential for management to influence CH4 emissions likely inflates error of CH4 emissions for regional and global CH4 models. This study employed a replicated factorial experimental design to investigate how management of the agricultural landscape, including grazing and/or management intensity, influences net CH4 emissions from embedded, seasonal subtropical wetlands. This research further determined key mechanisms by which management decisions at the landscape scale modulate CH4 emissions from the embedded wetlands. Net CH4 exchange was measured using a closed chamber system over two complete wet/dry seasonal cycles in 16 wetlands embedded in either agronomically improved pastures (improved wetlands) or less intensively grazed unfertilized seminative pastures (seminative wetlands), as well as in grazed and ungrazed wetlands in each treatment. Emissions of CH4 were higher from improved wetlands (2.82 μmol m−2 s−1) than seminative wetlands (0.75 μmol m−2 s−1), particularly during the wet season. Enhanced CH4 emissions in improved wetlands relative to seminative wetlands were caused by increased soil wetness and by higher biomass in improved seminative wetlands. Unlike subtropical flooded pastures, our results showed that grazers do not alter CH4 emissions from subtropical wetlands. Current and future changes in management intensity of pastures may cause shifts in net soil CH4 emissions from embedded subtropical wetlands, which could further enhance this emission source. Key Points: Wetlands are methane sources, but little is known regarding how surrounding agricultural practices impact emissionsWetlands embedded in intensely managed pastures have higher methane emissions than wetlands surrounded by seminative landscapesWhether a wetland was grazed or ungrazed had no impact on the amount of methane released from the wetland [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Growing demand for food from finite agricultural lands requires the optimization of agricultural management, including the potential interactive effects of these practices on ecosystems. We experimentally examined the interactive and temporal effects of three ranching practices (pasture management intensity, livestock grazing, and prescribed fire) on soil nutrients in 40 geographically-isolated seasonal wetlands. Wetlands were embedded in a subtropical ranch, and the long-term experiment used a factorial design with wetlands as experimental units. Soils (0–15 cm) were collected three times over 9 years; at experiment start (2007), one year after prescribed burns started (2009), and seven years later (2016). Samples were analyzed for soil bulk density, organic matter (OM), total nitrogen (N), carbon (C), and phosphorous (P). A lag effect was observed in response to fire; differences were not observed in 2009, but were detected in 2016 after multiple fire cycles had occurred. Rangeland practices showed 2- and 3-way interactive effects, especially for total P and N stocks. Total P increased most in the wetlands embedded within highly managed, grazed, and burned pastures (2.31 ± 0.76 g m −2 yr −1 ), consistent with legacy effects of historical fertilizer application, cattle activity, and ash deposit due to fire. Wetlands in semi-natural and burned pastures had the lowest rates of soil N storage (5.13 ± 7.33 g m −2 yr −1 ) compared to all other treatments (24.5 ± 10.8 g m −2 yr −1 ). Total C stocks were not significantly impacted by ranching practices throughout the study. In summary, ranching practices can additively and interactively alter soil nutrient stocks after a time lag, and legacy effects of P application still impact wetlands decades later. Our study is one of few focused on ranchland wetlands and shows that wetlands in highly managed, grazed, and/or burned pastures can sequester soil P and N, playing an important role in nutrient processing for agricultural landscapes and watersheds. [ABSTRACT FROM AUTHOR]

Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species-level abundance data from 62 plant communities across five continents to assess mechanisms of temporal stability across spatial scales. We assessed how asynchrony (i.e. different units responding dissimilarly through time) of species and local communities stabilised metacommunity ecosystem function. Asynchrony of species increased stability of local communities, and asynchrony among local communities enhanced metacommunity stability by a wide range of magnitudes (1-315%); this range was positively correlated with the size of the metacommunity. Additionally, asynchronous responses among local communities were linked with species' populations fluctuating asynchronously across space, perhaps stemming from physical and/or competitive differences among local communities. Accordingly, we suggest spatial heterogeneity should be a major focus for maintaining the stability of ecosystem services at larger spatial scales. [ABSTRACT FROM AUTHOR]

Greater understanding of land management effects on species richness and composition is needed to manage biodiversity-related ecosystem services in agricultural ecosystems. Here we studied responses of vascular plants, macroinvertebrates, and ectothermic vertebrates to local and regional factors in two ranchland management intensities (semi-natural and highly-managed). Samples were collected in 40 separate wetlands embedded in the two management intensities. Based on community assembly theory, we expected a shift from regional to local-based factors as predictors of communities where local conditions become more limiting. We also expected highly managed ranchlands to most strongly “filter” community membership to become more homogeneous. Both predictions were supported though results sometimes differed among taxa. Wetland communities embedded in highly managed pastures were more homogeneous and significantly different from those in semi-natural pastures. Overall, regional factors related to propagule dispersal were most important in semi-natural pastures, and local factors (especially nutrients) were most important in highly managed pastures. However, some community metrics were consistently affected most by local or regional factors regardless of land use intensity. For instance, vegetation richness and vertebrate composition were consistently influenced by local factors, whereas macroinvertebrate composition was consistently influenced by regional factors. Based on our results, biodiversity conservation will be most effective if management efforts focus on improving local habitat conditions in highly managed areas, and on preserving regional heterogeneity in more natural areas. Taxon-specific conservation strategies should account for taxon-specific sensitivities to local and regional processes. [ABSTRACT FROM AUTHOR]

Abstract: Semi-natural grasslands have become increasingly important to conservation in both temperate and subtropical regions due to their diversity and escalating pressures toward conversion or abandonment. As more semi-natural grasslands are incorporated into conservation easements or other protected areas, questions arise about appropriate management for maintaining biodiversity. We conducted an 8year split-plot experiment on the effect of season of burn and nutrient status on plant composition in semi-natural grassland released from ranchland management. Our objective was to find alternative approaches to manage semi-natural grasslands under varying nutrient enrichment when typical ranch management is ceased. We predicted that: (1) burning at high fertility would counteract competitive exclusion and increase diversity and that this increase would be greatest in the historical fire season (summer) to which species are adapted; and (2) that plant composition in plots released from disturbance would shift to greater abundance of competitive species, including shrubs, which would displace smaller grass and forb species and result in reduced diversity. Total species richness and graminoid richness were lowest in unburned, ungrazed plots. Graminoid richness was greatest in winter burned-grazed plots (due mainly to sedges) and forb richness was greatest in summer burn plots. In unburned plots, after 5years, a native shrub, Eupatorium capillifolium (Lam.) Small, and native forb, Lachnanthes caroliniana (Lam.) Dandy, became abundant and grasses declined. Winter burn plots were dominated by a small shrub, Euthamia graminifolia (L.) Nutt. var. hirtipes (Fernald) C. and J. Taylor. Our experiment suggests that maintaining grassland structure and reducing shrub cover in grasslands released from typical ranchland management in subtropical Florida requires burning, and that summer is the most beneficial season of burn to reduce shrub encroachment and encourage both graminoid and forb richness. [Copyright &y& Elsevier]

• The teabag index (TBI) was adopted to quantify subtropical wetland decomposition. • Land-use intensification, grazing, and fire interactively affected decomposition. • Hydrology and climate contributed to spatial–temporal variation in decomposition. • TBI is a useful indicator to inform wetland ecosystem service management. Understanding how global change drivers and their interactions affect decomposition in wetlands embedded in agricultural landscapes remains challenging, especially in tropical and subtropical biomes, which are disproportionately important for global carbon cycling yet with high uncertainties. In a long-term whole-ecosystem experiment, we used a widely-adopted indicator of decomposition, the Teabag Index (TBI), to investigate individual and interactive effects of surrounding land-use intensity, cattle grazing, and prescribed fire on seasonal wetland decomposition (i.e., decay rate k , and stabilization factor S) in an exemplar subtropical landscape in central-south Florida, USA. We ask: (1) How do land-use intensity and management practices affect the decomposition in seasonal wetlands? (2) How does wetland decomposition vary with hydrological gradient and seasonal climatic condition? (3) What are the dominant direct and indirect pathways through which land-use intensity and management practices affect wetland decomposition? Our results showed that, overall, surrounding land-use intensity exerted much stronger effects on litter decomposition compared to grazing and prescribed fire, and cattle grazing reduced decomposition rate k. There was a complex three-way interaction among land-use intensity, grazing and fire on the stabilization factor S – a proxy related to carbon sequestration potential. Grazing-fire interactive effects on S only existed in wetlands embedded in intensively-managed landscapes, where grazing reduced S in burned wetlands but did not affect S in unburned wetlands. Decay rate k showed profound temporal variation primarily driven by seasonal climatic conditions (especially precipitation), whereas S varied spatially along the hydrological gradient. Our structural equation modeling (SEM) analyses further revealed that effects on k were also indirectly manifested through changes on soil C/N, C/P, and pH, while effects on S were manifested through alterations in soil C/P ratio, pH, soil nutrients and water content. Our TBI results suggest that anthropogenic environmental changes, including land-use intensification, livestock introduction and fire suppression, could compromise carbon sequestration potential in tropical and subtropical seasonal wetlands. Our research highlights the importance of considering landscape context in wetland management and demonstrates the use of TBI as an indicator to quantify and inform combinations of land management and agricultural practices could conserve wetlands and sustain their vital functions and services, especially from the lens of promoting carbon storage and nutrient retention services. [ABSTRACT FROM AUTHOR]