Monitoring Change in a Central U.S. Calcareous Glade: Resampling Transects Established in 1993

Sutter, Robert; Govus, Thomas E.; Smyth, Regan L.; Nordman, Carl; Pyne, Milo; Hogan, Terri

doi:10.3375/043.031.0209

Cited by 10 publications

(6 citation statements)

References 3 publications

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“…However, recent changes to historical disturbance regimes, patterns in human land-use, and landscape fragmentation have altered grasslands throughout the southern U.S. (Noss 2013). At present, microhabitat conditions that are optimal for growth and flowering in A. bibullatus are now rare in unmanaged LCG ecotones, because fireintolerant cedar colonizes and persists in all but the thinnest soil microhabitats (Sutter et al 2011). Cedar encroachment is a homogenizing force that reduces light availability, decreases the abundance of C 4 grasses, increases soil moisture, and favors shade-tolerant bryophytes ( Fig.…”

Section: Forest Edge or Degraded Ecotone?mentioning

confidence: 99%

“…Glade ecotones are typically very narrow and markedly abrupt transition zones between open glade and surrounding forest, with deeper pockets of soil that support perennial forbs and C 4 grasses. Rare perennial forbs restricted to these ecotones often occur in small, declining populations (Albrecht and McCue 2010;Sutter et al 2011;Thompson et al 2006), and tend to be intolerant of the drought-prone open rock outcrops (Baskin and Baskin 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Although LCG ecotones are presumably maintained by locally abrupt changes in edaphic conditions (Baskin and Baskin 1999;Quarterman 1950a;Ware 2002), several lines of evidence suggest woody vegetation is expanding into rock outcrop systems and shrinking ecotone habitat. The abundance of fire-sensitive, mesophytic tree species is increasing in forests adjacent to LCGs (Adams et al 2012), and long-term declines in the abundance of LCG endemics are associated with recent increases in woody cover, especially Juniperus virginiana L. (commonly known as eastern red cedar; hereafter 'cedar'; Sutter et al 2011). Evidence of reduced gene flow and genetic variation over time in the focal species of this study further suggests that these island-like outcrops were historically connected by a more open landscape matrix (Morris et al 2002).…”

Section: Introductionmentioning

confidence: 99%

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Habitat change in insular grasslands: Woody encroachment alters the population dynamics of a rare ecotonal plant

Albrecht

Becknell

Long

2016

Biological Conservation

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Inferring habitat requirements of rare plants can be challenging when the few remaining populations occur in sites with divergent successional states. In island-like rock outcrop systems within forest landscapes, edaphic conditions are assumed to modulate successional patterns, but changes to disturbance regimes in the landscape matrix could alter ecotone microenvironments over time. We used demographic surveys and controlled experiments with a dispersal-limited and endangered ecotonal plant, Astragalus bibullatus, to test the hypothesis that woody encroachment from the forest matrix threatens rare plants in globally imperiled limestone cedar glades. Tree canopy cover was more important than edaphic conditions or ground-layer structure for explaining variation in demographic structure. As tree canopy cover increased, stem densities, flowering, and seed production declined. Over three-years, per plant inflorescence production, fruit production, and fruit set were markedly greater in open microhabitats than in edge or closed microhabitats. In contrast, seedling densities peaked in edge and closed microhabitats. Seedling recruitment and seed production were spatially decoupled across a canopy cover gradient, suggesting that shaded sites historically had lower tree canopy cover. Shade reduced growth rates and biomass of seedlings and adults under nonlimiting moisture conditions. Although A. bibullatus can persist in degraded ecotones using multiple demographic strategies, growth, flowering and seed production depend on open microhabitats. Our results demonstrate that woody encroachment effects in temperate grasslands extend to island-like rock outcrop systems with unique edaphic conditions. Conservation and recovery programs with rare ecotonal plants should integrate restoration of historical disturbance regimes in the landscape matrix.

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Section: Forest Edge or Degraded Ecotone?mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Habitat change in insular grasslands: Woody encroachment alters the population dynamics of a rare ecotonal plant

Albrecht

Becknell

Long

2016

Biological Conservation

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“…These species included two well‐studied species, S. baicalensis and S. barbata , and two species native to warm climates, S. racemosa and S. wrightii . Furthermore, we selected three other Scutellaria species widely distributed in Europe, Asia, and North America, including S. altissima , S. tournefortii , and S. parvula (Hasaninejad et al, 2009 ; Shang et al, 2010 ; Sutter et al, 2011 ), respectively. During this analysis, we unexpectedly identified a 4′‐hydroxyflavone which has not been included in the recent biosynthetic studies of S. baicalensis .…”

Section: Introductionmentioning

confidence: 99%

Metabolite profiling reveals organ‐specific flavone accumulation in Scutellaria and identifies a scutellarin isomer isoscutellarein 8‐O‐β‐glucuronopyranoside

et al. 2021

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Scutellaria is a genus of plants containing multiple species with well‐documented medicinal effects. S. baicalensis and S. barbata are among the best‐studied Scutellaria species, and previous works have established flavones to be the primary source of their bioactivity. Recent genomic and biochemical studies with S. baicalensis and S. barbata have advanced our understanding of flavone biosynthesis in Scutellaria . However, as over several hundreds of Scutellaria species occur throughout the world, flavone biosynthesis in most species remains poorly understood. In this study, we analyzed organ‐specific flavone profiles of seven Scutellaria species, including S. baicalensis , S. barbata , and two species native to the Americas ( S. wrightii to Texas and S. racemosa to Central and South America). We found that the roots of almost all these species produce only 4′‐deoxyflavones, while 4′‐hydroxyflavones are accumulated exclusively in their aerial parts. On the other hand, S. racemosa and S. wrightii also accumulated high levels of 4′‐deoxyflavones in their aerial parts, different with the flavone profiles of S. baicalensis and S. barbata . Furthermore, our metabolomics and NMR study identified the accumulation of isoscutellarein 8‐ O ‐β‐glucuronopyranoside, a rare 4′‐hydroxyflavone, in the stems and leaves of several Scutellaria species including S. baicalensis and S. barbata , but not in S. racemosa and S. wrightii . Distinctive organ‐specific metabolite profiles among Scutellaria species indicate the selectivity and diverse physiological roles of flavones.

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“…However, recent studies demonstrated that woody encroachment, especially eastern redcedar ( Juniperus virginiana L.), in glade-forest ecotones reduced growth and reproduction of Astragalus , although plants can survive for many years as remnant populations under dense shade (Albrecht et al., 2016). Long-term declines in the abundance of other LCG endemics have similarly been linked to increased woody encroachment (Sutter et al. 2011).…”

Section: Study Species and Reintroduction Programmentioning

confidence: 99%

Habitat suitability and herbivores determine reintroduction success of an endangered legume

Albrecht

Long

2019

Plant Diversity

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Reintroductions of rare plants require detailed knowledge of habitat requirements, species interactions, and restoration techniques. Thus, incremental experimentation over many years may be required to develop adequate knowledge and techniques for successful reintroduction. To determine drivers of extinction in historical reintroductions of a federally endangered perennial ( Astragalus bibullatus ), we developed a reintroduction experiment to disentangle the relative importance of habitat quality, herbivores, and restoration technique on reintroduction success. In a factorial design, we manipulated access to vertebrate herbivores across different habitat types (mesic ecotone vs. xeric barren), and used founder populations comprised of more transplants and genetic sources than previous reintroduction attempts. In mesic ecotones where historical reintroductions failed, excluding herbivores, thinning woody encroachment to improve habitat quality, outplanting across a greater array of microhabitats, and increasing founder population size did not improve demographic rates over previous attempts. Compared to mesic ecotones, transplant survival rates and cumulative fruit production were more than two and ten times greater, respectively, in a xeric barren ecotone characterized by open, grassy, and dry microenvironmental conditions. Across all sites, herbivores decreased probabilities of survival and flowering of larger adult plants. Flowering rates were 80% greater inside relative to outside herbivore exclusion cages. Over a four-year period, only a single uncaged plant produced fruit. Our study demonstrates that habitat quality and vertebrate herbivory are key drivers of long-term persistence in rare plant reintroductions. Using incremental experiments that build on previous knowledge gained from long-term monitoring can improve reintroduction outcomes.

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Monitoring Change in a Central U.S. Calcareous Glade: Resampling Transects Established in 1993

Cited by 10 publications

References 3 publications

Habitat change in insular grasslands: Woody encroachment alters the population dynamics of a rare ecotonal plant

Habitat change in insular grasslands: Woody encroachment alters the population dynamics of a rare ecotonal plant

Metabolite profiling reveals organ‐specific flavone accumulation in Scutellaria and identifies a scutellarin isomer isoscutellarein 8‐O‐β‐glucuronopyranoside

Habitat suitability and herbivores determine reintroduction success of an endangered legume

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