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

Published source details Boughton E.H., Quintana-Ascencio P.F., Bohlen P.J., Fauth J.E. & Jenkins D.G. (2016) Interactive effects of pasture management intensity, release from grazing and prescribed fire on forty subtropical wetland plant assemblages. Journal of Applied Ecology, 53, 159-170.
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This study is summarised as evidence for the following.

	Action	Category
	Exclude or remove livestock from historically grazed freshwater marshes Action Link
	Use prescribed fire to maintain or restore disturbance: freshwater marshes Action Link

Exclude or remove livestock from historically grazed freshwater marshes

A replicated, paired, controlled study in 2006–2009 in 40 freshwater marshes within a ranch in Florida, USA (Boughton et al. 2016) found that fencing to exclude cattle typically had no significant effect on the plant community composition, vegetation quality, species richness or diversity. Statistical significance was assessed for all results, but data were generally not reported. After 1–3 summers, the overall plant community composition was similar in marshes fenced to exclude cattle and marshes that remained grazed (data not reported). The same was true for the relative abundance of forbs, grass-like plants and shrubs. However, the relative abundance of dogfennel Eupatorium capillifolium was greater in exclusion marshes (2–5%) than in grazed marshes (0–1%). Exclusion and open marshes also had similar overall plant species diversity and richness, and similar native plant species richness. In two of three years, the extent to which species were characteristic of pristine Florida marshes was similar in exclusion and open marshes (data reported as a conservatism score). In the other year, the effect of cattle exclusion on this outcome was more complicated, differing between marshes and depending on whether they were burned or not. The study also reported data on the frequency of individual plant species (see original paper). Methods: The study used forty 0.5–1.5 ha marshes, grouped into five blocks of eight, within a 4,000-ha ranch. In February 2007, twenty marshes (four marshes/block) were fenced with barbed wire to exclude cattle (but not other mammals). The other 20 marshes (four marshes/block) were left open to cattle. In each block, two fenced and two grazed marshes were also burned in February 2008. Plant species presence/absence was recorded in October before (2006) and after (2007–2009) fencing, in fifteen 1-m² quadrats/marsh.

(Summarised by: Nigel Taylor)
Use prescribed fire to maintain or restore disturbance: freshwater marshes

A replicated, paired, controlled study in 2006–2009 in 40 freshwater marshes within a ranch in Florida, USA (Boughton et al. 2016) found that prescribed burning typically had no significant effect on the overall plant community composition, richness and diversity, but had mixed effects on vegetation quality. Statistical significance was assessed for all results, but data were generally not reported. After one and two summers, burned and unburned marshes contained similar overall plant communities (based on the species present and their abundance; data not reported). In four of six cases, burned and unburned marshes supported a similar relative abundance of forbs, grass-like plants and shrubs (with mixed effects depending on the group, year and grazing in the other two cases). Burned and unburned marshes also had similar overall plant species diversity and richness, and similar native plant species richness. After two summers, species in burned marshes were less characteristic of pristine Florida marshes, on average, than were the species in unburned marshes (data reported as a conservatism score). The effect of burning on this outcome after one summer was more complicated, differing between marshes and depending on whether they were grazed or not. Methods: The study used forty 0.5–1.5 ha marshes, grouped into five blocks of eight, within a 4,000-ha ranch that was historically managed with sporadic prescribed burns. In February 2008, twenty marshes (four marshes/block) were deliberately burned. The other 20 marshes (four marshes/block) were left unburned. In each block, two burned and two unburned marshes were also fenced to exclude cattle. Plant species presence/absence was recorded in October before (2006) and after (2008, 2009) burning, in fifteen 1-m² quadrats/marsh.

(Summarised by: Nigel Taylor)