Effects of Long-Term Removal of Sheep Grazing on the Seedbanks of High-Level Grasslands and Blanket Bogs

Marrs, Rob H.,McAllister, H.A.,Cho, K.,Rose, Rob J.,O'Reilly, J.,Furnes, M.,Lee, Hyohyemi National Institute of Ecology 2020 국립생태원회보(PNIE) Vol.1 No.1

Many areas of vegetation in the British uplands have reduced species diversity as a result of sheep overgrazing. It has been suggested that abandonment or re-wilding strategies might be used to reverse this. A likely first step would be the removal or reduction of grazing livestock from upland areas, with a presumption that this would lead to a recovery in species richness. However, we do not know if this would work, or the timescales involved. One of the important areas where more knowledge is needed is information on the size and composition of soil seedbanks as regeneration from zseed is a likely pathway of recovery. Here, we compared seedbanks in both grazed and ungrazed plots in five experiments at Moor House NNR in the northern Pennines; these sheep grazing exclusion experiments were started 52 and 63/64 years ago. Soil samples (n=10) were collected from both grazed and ungrazed plots in each experiment, and seed emergence counted in glasshouse trials. We detected only seeds of common species and very few dicotyledonous species. This suggests that the soil seedbank is unlikely to be a reliable source of the less common species for ecological restoration in these upland communities, suggesting an extinction debt. Therefore, seed addition and the creation of suitable safe-sites for germination may be needed in conjunction with grazing controls to allow the establishment of plants that will increase the species richness of the vegetation. However, this interventionist restoration approach remains to be tested.

An Adaptive Local Management Approach Cannot Overcome Large-Scale Trends: A Long-Term Case-Study for Saxifraga hirculus Conservation

Marrs, Rob H.,O'Reilly, John,Rose, Rob J.,Lee, HyoHyeMi,Alday, Josu G. National Institute of Ecology 2022 국립생태원회보(PNIE) Vol.3 No.3

Saxifraga hirculus is classified as a vulnerable plant species in Europe, and it is confined to base-rich flushes in the British uplands. However, a lack of available information about its conservation status hampers the development of adaptive strategies for its in-situ conservation, especially with respect to grazing. To assess the effectiveness of sheep grazing in maintaining viable populations of S. hirculus, we compared the community dynamics of the vegetation in a base-rich flush over 44 years in two plots: one sheep-grazed under business-as-usual sheep grazing densities and the other fenced to exclude grazing. The plots were established in 1972, and the abundances of all vascular plants, bryophytes, and litter were measured at six intervals until 2016. Our results showed that although the presence of S. hirculus was maintained in both plots over the 44 years, it declined and reached a minimum between 1995 and 2010, when it was close to extinction. Since 2013, Saxifraga has recovered only slightly. Interestingly, the S. hirculus response appeared to be independent of grazing treatment, but it mirrored wider changes in the vegetation composition and structure within the flush over the 44 years. These changes are similar to others reported in broader uplands that have been attributed to a combination of reduced nitrogen and sulfur deposition and global warming. Thus, the simple adaptive management approach of "just managing" sheep grazing appeared ineffectual for preserving the S. hirculus population. S. hirculus showed signs of recovery at the end of the study period within this base-rich flush.

Vertical and longitudinal variations in plant communities of drawdown zone of a monsoonal riverine reservoir in South Korea

Cho, Hyunsuk,Marrs, Rob H.,Alday, Josu G.,Cho, Kang-Hyun The Ecological Society of Korea 2019 Journal of Ecology and Environment Vol.43 No.2

Background: The plant communities within reservoir drawdown zones are ecologically important as they provide a range of ecosystem services such as stabilizing the shoreline, improving water quality, enhancing biodiversity, and mitigating climate change. The aim of the study was therefore to identify the major environmental factors affecting these plant communities within the drawdown zone of the Soyangho Reservoir in South Korea, which experiences a monsoonal climate, and thereafter to (1) elucidate the plant species responses and (2) compare the soil seedbank composition along main environmental gradients. Results: Two main environmental gradients affecting the plant community structure were identified within the drawdown zone; these were a vertical and longitudinal gradient. On the vertical dimension, a hydrological gradient of flood/exposure, the annual-dominated plant community near the water edge changed to a perennial-dominated community at the highest elevation. On the longitudinal dimension from the dam to the upstream, plant species composition changed from an upland forest-edge community to a lowland riverine community, and this was correlated with slope degree, soil particle size, and soil moisture content. Simultaneously, the composition of the soil seedbank was separated along the vertical gradient of the drawdown zone, with mainly annuals near the water edge and some perennials at higher elevations. The species composition similarity between the seedbank and extant vegetation was greater in the annual communities at low elevation than in the perennial communities at higher elevation. Conclusions: The structures of plant community and soil seedbank in the drawdown zone of a monsoonal riverine reservoir were changed first along the vertical and secondly along the longitudinal gradients. The soil seedbank could play an important role on the vegetation regeneration after the disturbances of flood/exposure in the drawdown zone. These results indicate that it is important to understand the vertical and longitudinal environmental gradients affecting shoreline plant community structure and the role of soil seedbanks on the rapid vegetation regeneration for conserving and restoring the drawdown zone of a monsoonal reservoir.

The Variation in the Species Composition of the Soil Seed Bank in the Natural Flood Plain Vegetation along the Urban Reach of Han River, South Korea

Lee, Hyo-Hye-Mi,Marrs, Rob H.,Lee, Eun-Ju The Korean Society of Limnology 2011 생태와 환경 Vol.44 No.1

We described the above-ground plant species composition and measured a range of soil physico-chemical properties and the composition and size of the soil seed bank in the remnant natural vegetations on the flood plains of the Han River within Seoul, South Korea. We used analysis of variance and multivariate analyses to analyse the data and S${\o}$rensen's similarity index to compare the composition of the vegetation and seed banks. The soils were circum-neutral and composed of mainly sand and silt fractions with a very limited clay component; a gradient based on sand/clay proportions was identified. The soil seed banks varied markedly between- and within-sites and had much greater species diversity than the above-ground vegetation. Two of the major dominants in the vegetation (Miscanthus saccariflorus and Phragmites australis) were found at very low densities in the seed bank. The site differences appeared to be correlated with the sand-clay gradient, suggesting that the soil properties differentially affected seed inputs into the soil, or that the processes than controlled sediment deposition during floods was also important in differentially affecting seed deposition. Lastly, there was relatively little similarity between the vegetation, dominated mainly by perennials, and the seed bank which contained a relatively large proportion of annuals and biennials. This result suggests that after disturbance caused by flooding there is the potential for many other species to colonize. This may impinge on the regeneration potential of the sites and cause concern for the future conservation of these important remnants of natural vegetation.

Floristic Composition and Phytomass in the Drawdown Zone of the Soyangho Reservoir, Korea

Cho, Hyunsuk,Jin, Seung-Nam,Marrs, Rob H.,Cho, Kang-Hyun Korean Society of Ecology and Infrastructure Engin 2018 Ecology and resilient infrastructure Vol.5 No.2

The Soyangho Reservoir in Korea has a large drawdown zone, with an annual maximum water level fluctuation of 37 m due to dam operations to maintain a stable water supply and control flooding, especially during the monsoon period. The floristic composition, distribution and biomass of the major plant communities in the drawdown zone of the Soyangho Reservoir were assessed in order to understand their responses to the wide water level fluctuation. Species richness of vascular plants was low, and species composition was dominated by herbaceous annuals. Principal coordinates analysis using both flora and environmental data identified slope angle and the distance from the dam as important factors determining floristic composition. The species richness was low in the steep drawdown zone close to the dam, where much of the soil surface was almost devoid of vegetation. In shallower slopes, distant from the dam plant communities composed of mainly annuals were found. The large fluctuation in water level exposed soil where these annuals could establish. An overall biomass of 122 t (metric tons) Dry Matter was estimated for the reservoir, containing ca 3.6 t N (nitrogen) and ca 0.3 t P (phosphorus); the role of the vegetation of the drawdown zone in carbon sequestration and water pollution were briefly discussed.

Identification of a Novel Keyhole Phenotype in Double-Disk Diffusion Assays of Clindamycin-Resistant Erythromycin-Sensitive Strains of <i>Streptococcus agalactiae</i>

Srinivasan, Usha,Miller, Brady,Debusscher, Joan,Marrs, Carl F.,Zhang, Lixin,Seo, Yong Soo,Oh, Kwan-Young,Kim, Moon Young,Yoon, Hye-Ryung,Ki, Moran,Foxman, Betsy Mary Ann Liebert 2011 Microbial drug resistance Vol.17 No.1

The Variation in the Species Composition of the Soil Seed Bank in the Natural Flood Plain Vegetation along the Urban Reach of Han River, South Korea

( Hyo Hye Mi Lee ),( Rob H. Marrs ),( Eun Ju Lee ) 한국하천호수학회(구 한국육수학회) 2011 생태와 환경 Vol.44 No.1

We described the above-ground plant species composition and measured a range of soil physico-chemical properties and the composition and size of the soil seed bank in the remnant natural vegetations on the flood plains of the Han River within Seoul, South Korea. We used analysis of variance and multivariate analyses to analyse the data and Sorensen`s similarity index to compare the composition of the vegetation and seed banks. The soils were circum-neutral and composed of mainly sand and silt fractions with a very limited clay component; a gradient based on sand/clay proportions was identified. The soil seed banks varied markedly between- and within-sites and had much greater species diversity than the above-ground vegetation. Two of the major dominants in the vegetation (Miscanthus saccariflorus and Phragmites australis) were found at very low densities in the seed bank. The site differences appeared to be correlated with the sand-clay gradient, suggesting that the soil properties differentially affected seed inputs into the soil, or that the processes than controlled sediment deposition during floods was also important in differentially affecting seed deposition. Lastly, there was relatively little similarity between the vegetation, dominated mainly by perennials, and the seed bank which contained a relatively large proportion of annuals and biennials. This result suggests that after disturbance caused by flooding there is the potential for many other species to colonize. This may impinge on the regeneration potential of the sites and cause concern for the future conservation of these important remnants of natural vegetation.

Floristic Composition and Phytomass in the Drawdown Zone of the Soyangho Reservoir, Korea

Hyunsuk Cho,Seung-Nam Jin,Rob H. Marrs,Kang-Hyun Cho 응용생태공학회 2018 Ecology and resilient infrastructure Vol.5 No.2

The Soyangho Reservoir in Korea has a large drawdown zone, with an annual maximum water level fluctuation of 37 m due to dam operations to maintain a stable water supply and control flooding, especially during the monsoon period. The floristic composition, distribution and biomass of the major plant communities in the drawdown zone of the Soyangho Reservoir were assessed in order to understand their responses to the wide water level fluctuation. Species richness of vascular plants was low, and species composition was dominated by herbaceous annuals. Principal coordinates analysis using both flora and environmental data identified slope angle and the distance from the dam as important factors determining floristic composition. The species richness was low in the steep drawdown zone close to the dam, where much of the soil surface was almost devoid of vegetation. In shallower slopes, distant from the dam plant communities composed of mainly annuals were found. The large fluctuation in water level exposed soil where these annuals could establish. An overall biomass of 122 t (metric tons) Dry Matter was estimated for the reservoir, containing ca 3.6 t N (nitrogen) and ca 0.3 t P (phosphorus); the role of the vegetation of the drawdown zone in carbon sequestration and water pollution were briefly discussed.

The Relationship between the Soil Seed Bank and Above-ground Vegetation in a Sandy Floodplain, South Korea

Hyung-Jin Cho,Seung-Nam Jin,Hyohyemi Lee,Rob H. Marrs,Kang-Hyun Cho 응용생태공학회 2018 Ecology and resilient infrastructure Vol.5 No.3

In a monsoonal climate, the soil seed bank can play an important role in plant regeneration after the severe annual floods that disturb above-ground vegetation within the riparian zone. To investigate the relationship between the soil seed bank and vegetation, we measured the species composition of the soil seed bank and the extant above-ground vegetation in six major plant communities (Artemisia selengensis, Miscanthus sacchariflorus, Persicaria nodosa, Phalaris arundinacea, Phragmites japonica, and Rorippa palustris) in the Cheongmicheon Stream, Korea. A total of 21 species germinated from the floodplain soil seed banks. The most diverse seed bank (21 species) was found in the A. selengensis community, wheres the lowest number of species was found in the R. palustris community (2 species). Most soil seed banks were composed of annuals (90%), exceptions being Rumex crispus and Artemisia princeps, which are perennial ruderals. The similarity of species composition between the soil seed bank and above-ground vegetation was low with Sorensen’s similarity indices averaging 29% (range 12 - 42%). Crucially, existing dominant perennials of the extant vegetation including A. selengensis, M. sacchariflorus, P. japonica and P. arundinacea were absent from the soil seed bank. In conclusion, the soil seed banks of the floodplains of the Cheongmicheon Stream were mainly composed of viable seeds of ruderal plants, which could germinate rapidly after severe flood disturbance. The soil seed bank may, therefore, be useful for the restoration of the early succession stages of riparian vegetation after flood disturbances.

Effects of flooding on the seed bank and soil properties in a conservation area on the Han River, South Korea

Lee, H.,Alday, J.G.,Cho, K.H.,Lee, E.J.,Marrs, R.H. Elsevier Science 2014 Ecological engineering Vol.70 No.-

Flooding can have a major impact on riverside plant communities, and this is likely to be especially important in monsoonal climates, where large floods occur after heavy rain. In urban areas where riparian vegetation remnants are the only vegetation of conservation interest remaining, understanding the impacts that floods have on these ecosystems is needed to inform their future conservation. Accordingly, we assessed the impact of a flood caused by Typhoon ''Ewiniar'' on the soil seed bank of five plant communities of the only remaining fragment of high-quality riverine habitat within the Seoul city stretch of the Han River (South Korea). We surveyed the seed bank composition of the five dominant plant communities before and after the flood. We also measured selected soil physico-chemical properties in each community. We used univariate and multivariate methods to examine the effect of the flood on both seed bank and soil physico-chemical properties. Flooding resulted in variable deposition of sediment within the plant communities; four communities varied from 14.6 to 18.8cm but the fifth (dominated by Miscanthus sacchariflorus) had much less sediment (4.8cm). The physico-chemical properties of the surface soil also changed after the flood, with the sediment particle size being the most affected. The species richness and composition of the seed bank suffered significant changes after the flood. In both cases there was a homogenization process, with was also impinged on species with different life-forms (annuals and perennials). Our results suggest that an extreme flood can affect the riparian vegetation seed bank by removing wetland plant species and allowing common and ruderal species to establish. There may also be different interactions between the different plant communities in terms of sediment capture and this translates into altered soil conditions and seed banks. These results are of use to conservation policy-makers aiming to conserve a native flora within severely modified urban rivers, and these remnant areas can provide an important seed source of wetland plants to aid restoration of riparian ecosystems.