Search

Sustainable agricultural intensification could improve ecosystem service multifunctionality, yet empirical evidence remains tenuous, especially regarding consequences for spatially coupled ecosystems connected by flows across ecosystem boundaries (i.e., metaecosystems). Here we aim to understand the effects of land-use intensification on multiple ecosystem services of spatially connected grasslands and wetlands, where management practices were applied to grasslands but not directly imposed to wetlands. We synthesize long-term datasets encompassing 53 physical, chemical, and biological indicators, comprising >11,000 field measurements. Our results reveal that intensification promotes high-quality forage and livestock production in both grasslands and wetlands, but at the expense of water quality regulation, methane mitigation, non-native species invasion resistance, and biodiversity. Land-use intensification weakens relationships among ecosystem services. The effects on grasslands cascade to alter multifunctionality of embedded natural wetlands within the metaecosystems to a similar extent. These results highlight the importance of considering spatial flows of resources and organisms when studying land-use intensification effects on metaecosystems as well as when designing grassland and wetland management practices to improve landscape multifunctionality.It is not clear how agricultural intensification affects spatially coupled ecosystems. Here, the authors use long-term datasets on managed grasslands coupled with unmanaged wetlands showing that grassland intensification affects ecosystem service multifunctionality of spatially coupled wetlands [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]

Plant–plant interactions influence community assembly and species responses to environmental change. However, species interactions are complex phenomena influenced by context and scale. We conducted a one-year replacement experiment between two grasses in subtropical grasslands (native Axonopus fissifolius and non-native Paspalum notatum) in central Florida, USA. We evaluated interactions between these species at three ecological scales, 'pairwise interactions,' 'patch' (33 cm × 33 cm), and 'plot' (1 m x 3 m) and along a gradient (15 levels) of increasing non-native and decreasing native plot ground cover within enclosures in semi-native pastures. We transplanted 18 individuals of each species per plot (18 × 30 plots = 1080 plants in total) in a 2 × 2 design intersecting direct pairwise interactions (additional transplanted neighbor: absent/present) with recipient patch type (Axonopus fissifolius/Paspalum notatum). Leaf length, leaf number, and plant biomass were measured at the beginning and the end of the experiment along with soil nutrients and pH at patch level. Over 92% of the transplants survived. We observed an interactive effect between patch type (non-native vs. native dominated) and plant abundance at plot level on plant performance, suggesting that indirect effects at larger spatial scales can influence effects at smaller scales. Surprisingly, both species exhibited enhanced performance with increasing abundance of the non-native species at plot level. We discuss several mechanisms explaining these indirect effects including Paspalum notatum-induced changes in soil pH, soil feedbacks from the soil microbial community, preconditioning effects of the native species on the recipient soil, and positive density dependence effects after transplantation. [ABSTRACT FROM AUTHOR]

Beef cattle production in Florida consists of extensively managed cow-calf operations where animals are stocked on native and planted pastures with minimal P inputs. Despite the extensive literature documenting multiple benefits of cow-calf systems, concerns exist regarding their negative impacts on water quality, especially P in ecologically sensitive areas. This study evaluated farm-to-gate P balance for two cow-calf operations [a 3159-ha section of Archbold's Buck Island Ranch (BIR) and the 1170 ha University of Florida Range Cattle Research and Education Center (RCREC)] both managed using typical regional practices. Mean annual P inputs were 2.4 and 2.1 kg P ha−1 yr−1 in BIR and RCREC, respectively, with animal feed being the single largest source of P imported (71% and 42% of total P inputs in BIR and RCREC, respectively). Total P outputs were similar for both operations (~ 1.9 kg P ha−1 yr−1) and was mostly (77%) from sold animals. Estimated P balance was nearly balanced for both RCREC and BIR (0.3 and 0.5 kg P ha−1 yr−1, respectively), largely as a result of significant reductions in fertilizer inputs from earlier years. The relatively high enterprise efficiency (proportion of P outputs in animal product relative to P inputs; 81 to 97%) suggested that typical cow-calf operations as those evaluated in this study represent an environmentally sustainable land management. Although improving nutrient efficiency is an important goal for sustainable agriculture, achieving neutral balance may be unrealistic in low-input systems that are largely affected by seasonal variations in weather and soil legacy P effects. [ABSTRACT FROM AUTHOR]

Unpalatable plant species often act as biotic refuges by protecting neighboring plants from herbivores. This positive interaction can increase functional diversity in grazed ecosystems by protecting species sensitive to grazing. While many studies investigate pair-wise interactions between benefactors and beneficiaries, few show that these interactions result in community composition effects. We studied the effect of an unpalatable plant, Juncus effusus, on wetland plant communities in grazed and ungrazed plots. We tested the following predictions: (1) Juncus would increase plant functional diversity in grazed wetlands; (2) Juncus would have significant effects on community composition; and (3) the effects of Juncus on other species would change across the grazing gradient. We found that Juncus preserved functional diversity in grazed wetland communities by protecting species that decrease with grazing pressure. In multivariate analyses, grazing was the strongest driver of species composition but we found significant effects of Juncus on both vegetation change and species composition in grazed plots. Interactions with Juncus were facilitative in grazed plots and competitive in ungrazed plots, but did not vary along the grazing gradient (0.15-1.7 cows/ha). These results indicate that Juncus has significant community composition effects in grazed wetland plant communities. Understanding the effects of plant interactions such as these at the community level is essential to applying plant interactions to restoration or management. [ABSTRACT FROM AUTHOR]

Global change is associated with variable shifts in the annual production of aboveground plant biomass, suggesting localized sensitivities with unclear causal origins. Combining remotely sensed normalized difference vegetation index data since the 1980s with contemporary field data from 84 grasslands on 6 continents, we show a widening divergence in site-level biomass ranging from +51% to -34% globally. Biomass generally increased in warmer, wetter and species-rich sites with longer growing seasons and declined in species-poor arid areas. Phenological changes were widespread, revealing substantive transitions in grassland seasonal cycling. Grazing, nitrogen deposition and plant invasion were prevalent in some regions but did not predict overall trends. Grasslands are undergoing sizable changes in production, with implications for food security, biodiversity and carbon storage especially in arid regions where declines are accelerating., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Herbivores alter plant biodiversity (species richness) in many of the world's ecosystems, but the magnitude and the direction of herbivore effects on biodiversity vary widely within and among ecosystems. One current theory predicts that herbivores enhance plant biodiversity at high productivity but have the opposite effect at low productivity. Yet, empirical support for the importance of site productivity as a mediator of these herbivore impacts is equivocal. Here, we synthesize data from 252 large-herbivore exclusion studies, spanning a 20-fold range in site productivity, to test an alternative hypothesis-that herbivore-induced changes in the competitive environment determine the response of plant biodiversity to herbivory irrespective of productivity. Under this hypothesis, when herbivores reduce the abundance (biomass, cover) of dominant species (for example, because the dominant plant is palatable), additional resources become available to support new species, thereby increasing biodiversity. By contrast, if herbivores promote high dominance by increasing the abundance of herbivory-resistant, unpalatable species, then resource availability for other species decreases reducing biodiversity. We show that herbivore-induced change in dominance, independent of site productivity or precipitation (a proxy for productivity), is the best predictor of herbivore effects on biodiversity in grassland and savannah sites. Given that most herbaceous ecosystems are dominated by one or a few species, altering the competitive environment via herbivores or by other means may be an effective strategy for conserving biodiversity in grasslands and savannahs globally.