Vascular plant colonization and vegetation development on sea-born volcanic islands in the Aegean (Greece)

Climate change is expected to alter the Arctic’s carbon (C) balance and changes in these C-rich ecosystems may contribute to a positive feedback on global climate change. Low-center mudboils, a form of patterned ground in the Arctic, are distinct landforms in which the exchange of greenhouse gases between the atmosphere and soil has not been fully characterized, but which may have an important influence on the overall C balance of tundra ecosystems. Chamber systems were used to sample net ecosystem exchange of CO2 (NEE) and CO2 and CH4 effluxes along a 35-m transect intersecting two mudboils in a wet sedge fen in Canada’s Southern Arctic (lat. 64°52′N, long. 111°34′W) during the summer months in 2008. Mudboil features gave rise to dramatic variations in vegetation, soil temperature and thaw depth, and soil organic matter content along this transect. Variations in NEE were driven by variations in the amount of vascular vegetation, while CO2 and CH4 effluxes were remarkably similar among the two mudboil (CO2 effluxes: 1.1 ± 0.9 and 1.4 ± 0.7 µmol m-2 s-1; CH4 effluxes: 83.1 ± 189.4 and 23.1 ± 9.4 nmol m-2 s-1, ± 1 standard deviation) and the sedge fen (CO2 effluxes: 1.6 ± 0.7 mol m-2 s-1 ; CH4 effluxes: 28.0 ± 62.0 nmol m-2 s-1) sampling areas. Vegetation appeared to play an important role in limiting temporal variations in CH4 effluxes through plant mediated transport in both mudboil and sedge fen sampling areas. One of the mudboils had negligible vascular plant colonization presumably due to more active frost heave processes. The relatively high CO2 and CH4 efflux in this mudboil area was speculated to be a result of growth and decomposition of cryptogamic organisms, inflow of dissolved organic C, and warmer soil temperatures. Key words: Patterned ground, nonsorted circle, tundra, net ecosystem exchange, methane, carbon dioxide

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Plant colonization, succession and ecosystem development on Surtsey with reference to neighbouring islands

Biogeosciences ◽

10.5194/bg-11-5521-2014 ◽

2014 ◽

Vol 11 (19) ◽

pp. 5521-5537 ◽

Cited By ~ 22

Author(s):

B. Magnússon ◽

S. H. Magnússon ◽

E. Ólafsson ◽

B. D. Sigurdsson

Keyword(s):

Species Richness ◽

Plant Biomass ◽

Vascular Plant ◽

Plant Cover ◽

Soil Formation ◽

Plant Succession ◽

Permanent Plots ◽

Plant Colonization ◽

Nutrient Input ◽

Species Richness And Diversity

Abstract. Plant colonization and succession on the volcanic island of Surtsey, formed in 1963, have been closely followed. In 2013, a total of 69 vascular plant species had been discovered on the island; of these, 59 were present and 39 had established viable populations. Surtsey had more than twice the species of any of the comparable neighbouring islands, and all of their common species had established on Surtsey. The first colonizers were dispersed by sea, but, after 1985, bird dispersal became the principal pathway with the formation of a seagull colony on the island and consequent site amelioration. This allowed wind-dispersed species to establish after 1990. Since 2007, there has been a net loss of species on the island. A study of plant succession, soil formation and invertebrate communities in permanent plots on Surtsey and on two older neighbouring islands (plants and soil) has revealed that seabirds, through their transfer of nutrients from sea to land, are major drivers of development of these ecosystems. In the area impacted by seagulls, dense grassland swards have developed and plant cover, species richness, diversity, plant biomass and soil carbon become significantly higher than in low-impact areas, which remained relatively barren. A similar difference was found for the invertebrate fauna. After 2000, the vegetation of the oldest part of the seagull colony became increasingly dominated by long-lived, rhizomatous grasses (Festuca, Poa, Leymus) with a decline in species richness and diversity. Old grasslands of the neighbouring islands Elliđaey (puffin colony, high nutrient input) and Heimaey (no seabirds, low nutrient input) contrasted sharply. The puffin grassland of Elliđaey was very dense and species-poor. It was dominated by Festuca and Poa, and very similar to the seagull grassland developing on Surtsey. The Heimaey grassland was significantly higher in species richness and diversity, and had a more even cover of dominants (Festuca/Agrostis/Ranunculus). We forecast that, with continued erosion of Surtsey, loss of habitats and increasing impact from seabirds a lush, species-poor grassland will develop and persist, as on the old neighbouring islands.

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Vascular plant colonisation of Surtsey Island (1965-1990) - a dataset

Biodiversity Data Journal ◽

10.3897/bdj.8.e54812 ◽

2020 ◽

Vol 8 ◽

Author(s):

Pawel Wasowicz ◽

Sally Thorsteinsson ◽

Borgþór Magnússon ◽

Eyþór Einarsson ◽

Valgeir Bjarnason ◽

...

Keyword(s):

Primary Succession ◽

Vascular Plant ◽

Field Studies ◽

Plant Distribution ◽

Distribution Data ◽

Plant Colonisation ◽

Unique Event ◽

Volcanic Islands ◽

Colonisation Dynamics ◽

Succession Processes

The process of ecosystem development over time that takes place on a new substrate devoid of biological activity (such as, for example, lava) is called primary succession. Research on primary succession is not easy, as it is limited to rare occasions when a piece of land totally lacking in any pre-existing life occurs. The emergence of volcanic islands is such an occasion; it is a unique event that allows a natural experiment in the study of colonisation processes and primary succession. Surtsey (located in the Vestmannaeyar archipelago off the southern coast of Iceland) is an iconic example of a place where primary succession has been studied for decades and where human disturbance has been minimised due to significant geographic isolation and early protection efforts. Here, we present a georeferenced dataset of vacular plant occurrences collected during the field studies carried out on Surtsey Island during the first three decades of its existence. To date, no dataset containing plant distribution data documenting the process of early stages of colonisation of Surtsey has been published. What is more, to our knowledge, there is no other dataset that can be compared with our Surtsey data that is readily available for researchers working on plant colonisation dynamics and primary succession processes. Here, we present a complete, geo-referenced dataset of all plant occurrences (10,094 in total) collected on Surtsey between 1965 and 1990.

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Non-native species in the vascular flora of highlands and mountains of Iceland

10.7287/peerj.preprints.1165v1 ◽

2015 ◽

Author(s):

Pawel Wasowicz

Keyword(s):

Plant Species ◽

Native Species ◽

Hot Springs ◽

Vascular Plant ◽

Temporal Trends ◽

Plant Colonization ◽

Native Plant ◽

Alien Plant ◽

Alien Flora ◽

Central Highland

Highlands and mountains of Iceland (defined here as areas located above 400 m a.s.l) are considered to be the largest remaining wilderness areas in Europe. The present study provides first comprehensive and up-to-date data on non-native plant species from this area. The study was aimed to provide a checklist of alien plant species recorded from highland and mountain areas of Iceland, assess their naturalisation status, define spatial patterns and hotspots of their distribution and analyse temporal trends in the data. The presence of 18 non-native vascular plant species was evidenced including 13 casuals and 5 naturalised taxa (1 invasive). The results showed that the central highland is most vulnerable to alien plant colonisation, while mountain and highland areas in other parts of the country are much less impacted by non-native plant taxa. Clear hotspots of occurrence of alien flora can be defined and their geographic location corresponds to places of touristic interest such as hot springs, geothermal areas, mountain huts and shelters as well as main roads and tracks. Temporal trends characterizing non-native plant colonization show clearly that the process is still in its initial phase. The research suggests that human-mediated dispersal is the major force contributing to increased invasion risk within the investigated area.

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Non-native species in the vascular flora of highlands and mountains of Iceland

10.7287/peerj.preprints.1165v3 ◽

2015 ◽

Author(s):

Pawel Wasowicz

Keyword(s):

Alien Species ◽

Plant Species ◽

Hot Spots ◽

Vascular Plant ◽

Temporal Trends ◽

Second Step ◽

Plant Colonization ◽

Native Plant ◽

Alien Plant ◽

Vascular Plant Species

The highlands and mountains of Iceland, defined here as areas located above 400 m above sea level (m.a.s.l.) are one of the largest remaining wilderness areas in Europe. The present study was aimed to provide the first comprehensive and up-to-date data on non-native plant species from this region. The study was aimed to answer the following questions: (1) How many non-native vascular plant species inhabit highland and mountainous environments in Iceland? (2) Do temporal trends in alien species immigration to Iceland and highland areas differ? (3) Do human disturbed and undisturbed areas within Icelandic highlands differ in terms of alien species occurrence? (4) Is spread within the highland areas a second step in alien plant colonization? and (5) Can we point out hot-spots in the distribution of non native taxa within highlands? Overall, 16 non-native vascular plant species were detected, including 11 casuals and 5 naturalized taxa (1 invasive). Results showed that temporal trends in alien species immigration to Iceland and to highland areas are similar, but it is clear that the process of colonization of highland areas is still in its initial phase. It was evidenced that non-native plants tend to occur close to man-made infrastructure and buildings including huts, shelters, road network etc. Analysis of spatio-temporal patterns showed that the spread within highland areas is a second step in non-native plant colonization in Iceland. Several statically significant hot spots of alien plant occurrences were be identified using Getis-Ord Gi* statistic and linked to human disturbance. This research suggests that human-mediated dispersal is the main driving force increasing the risk of invasion in Icelandic highlands and mountain areas.

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Seabirds and seals as drivers of plant succession on Surtsey

Surtsey research ◽

10.33112/surtsey.14.10 ◽

2020 ◽

Vol 14 ◽

pp. 115-130

Author(s):

Borgthór Magnússon ◽

Gudmundur A. Gudmundsson ◽

Sigmar Metúsalemsson ◽

Sandra M. Granquist

Keyword(s):

Plant Cover ◽

Plant Succession ◽

Present Species ◽

Permanent Plots ◽

Plant Colonization ◽

Grey Seal ◽

Breeding Area ◽

Vegetation Development ◽

Dense Patch ◽

First Time

Plant colonization and succession on Surtsey have been monitored since 1965. In 2019, the 75th species of vascular plants was detected on the island, 62 species were present and about 40 species had established viable populations. Over the last decade colonization has slowed down and the number of present species not increased. The rising number of seagulls breeding on the island after 1985 had a great impact on plant colonization and vegetation development. While most parts of the island remained barren, a grassland area (13 ha in 2018) developed in the main seagull breeding colony on the southern part of the island. This development is attributed to transfer of nutrients from sea to land by the seagulls. In recent years a dense patch of vegetation, 2 ha in 2018, has also developed on the low, northern spit of the island, where a few pairs of seagulls breed in the spring and grey seals haul out and breed in the fall in considerable numbers. In a survey conducted during the grey seal pupping period in 2019, the seal abundance and spatial distribution was mapped accurately for the first time. The results show that the dense vegetation of the spit and seal distribution are clearly overlapping. The continuous shrinking of the island and its spit has led to an increasing concentration of the seals in their breeding area. Based on a literature survey we estimated the nitrogen (N) input from sea to land by the grey seals as 9-13 kg N/ha in 2019. This compares to an estimated input of 5-30 kg N/ha/yr by the seagulls breeding in the same area during 2015-2019. Within the grey seal and seagull breeding area on the spit of the island, a distinct community of shore plants has developed. Measurements of plant cover and biomass in permanent plots on Surtsey in 2018 and 2019 show that development on part of the spit is reaching a similar state as in the old gull colony on the southern part of the island. This suggests that the grey seals along with the seagulls are important drivers of plant succession on the northern spit. Further research on the effects of the seals on nutrient transfer from sea to land and ecosystem development on Surtsey is recommended.

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Application of the Scholander pressure bomb to studies on endophytic bacteria of plants

Canadian Journal of Microbiology ◽

10.1139/m97-058 ◽

1997 ◽

Vol 43 (5) ◽

pp. 411-416 ◽

Cited By ~ 18

Author(s):

J. Hallmann ◽

J. W. Kloepper ◽

R. Rodríguez-Kábana

Keyword(s):

Endophytic Bacteria ◽

Vascular Plant ◽

Taxonomic Diversity ◽

Common Species ◽

Root Surface ◽

Plant Colonization ◽

Root Cortex ◽

Bacillus Spp ◽

Pressure Bomb ◽

Bomb Method

The Scholander pressure bomb system, which expresses vascular plant sap, was compared with the trituration method, in which roots are surface disinfested and triturated, for recovery of endophytic bacteria. The two methods were compared for recovery of indigenous and introduced endophytes from roots of several plant genera. The pressure bomb method was acceptable for routine recovery of endophytes from cotton (Gossypium hirsutum), soybean (Glycine max), and bean (Phaseolus vulgaris), but owing to tissue collapse under pressure, the method did not work reliably for cucumber (Cucumis sativa) or tomato (Lycopersicon esculentum) seedlings. High bacterial densities on the root surface, experimentally obtained by dipping cotton roots into a suspension of Enterobacter asburiae JM22 immediately prior to processing, did not affect the population densities of recovered indigenous endophytic bacteria by the pressure bomb technique but resulted in increased bacterial densities for the trituration method. Internal populations of JM22 following application as a seed treatment were statistically equivalent with the trituration and pressure bomb techniques. Analysis of taxonomic diversity of a group of indigenous endophytes recovered with the trituration and pressure bomb techniques indicated some differences between the two groups. The total number of bacterial genera and species recovered was greater using the pressure bomb method. Gram-positive species, such as Bacillus spp., were more frequently isolated with the trituration method than with the pressure bomb method. Agrobacterium radiobacter and less common species were more often isolated using the pressure bomb technique. Pseudomonas spp. and Phyllobacterium spp. were recovered with equal frequencies using both techniques. These results suggest that the two techniques sample two different internal habitats available for colonization by endophytic bacteria, i.e., the trituration method recovering mainly endophytes residing in the root cortex and the pressure bomb method detecting vascular colonists. A combination of both methods is recommended for understanding the full pattern of internal plant colonization by endophytic bacteria.Key words: endophytic bacteria, Scholander pressure bomb, isolation method, cotton.

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Prevalence and phenology of mycorrhizal colonization across populations of Lycopodiella inundata

10.1101/2020.05.07.080192 ◽

2020 ◽

Author(s):

Jill Kowal ◽

Elena Arrigoni ◽

Jordi Serra ◽

Martin Bidartondo

Keyword(s):

Mycorrhizal Fungi ◽

Habitat Restoration ◽

Vascular Plant ◽

Species Conservation ◽

Hyphal Growth ◽

Occurrence Rate ◽

Plant Colonization ◽

Functional Studies ◽

Temperature And Precipitation ◽

Nutrient Enhancement

AbstractMycorrhizal fungi are critical components of terrestrial habitats and agroecosystems. Recently, Mucoromycotina fine root endophyte (MucFRE) fungi were found to engage in nutritional mutualism with the rare plant Lycopodiella inundata (‘marsh clubmoss’), one of the earliest vascular plant lineages known to associate with MucFRE. The extent to which this mutualism plays a role in resilient plant populations can only be understood by examining its occurrence rate and phenological patterns.To test for prevalence and seasonality in colonization, we examined 1,297 individual L. inundata roots collected during spring and autumn 2019 from 11 semi-natural heathlands in Britain and the Netherlands. We quantified presence/absence of MucFRE-like hyphae and vesicles and explored possible relationships between temperature and precipitation in the months immediately before sampling.MucFRE-like hyphae were the dominant mycorrhizal fungi observed in all of the examined heathlands. However, we found significant differences in colonization between the two seasons at every site. Overall, 14% of L. inundata roots were colonised in spring (2.4% with vesicles) compared with 86% in autumn (7.6% with vesicles). Colonization levels between populations were also significantly different, and correlated with temperature and precipitation, suggesting some local environments may be more conducive to hyphal growth.These marked seasonal differences in host-plant colonization suggest that results about mycorrhizal status - typically drawn from single time point collections - should be carefully interpreted. Our findings are directly relevant to habitat restoration, species conservation plans, agricultural bio-inoculation nutrient enhancement treatments, microbial diversity and functional studies of host plants and symbionts.

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Non-native species in the vascular flora of highlands and mountains of Iceland

PeerJ ◽

10.7717/peerj.1559 ◽

2016 ◽

Vol 4 ◽

pp. e1559 ◽

Cited By ~ 10

Author(s):

Pawel Wasowicz

Keyword(s):

Alien Species ◽

Plant Species ◽

Hot Spots ◽

Native Species ◽

Vascular Plant ◽

Temporal Trends ◽

Plant Colonization ◽

Native Plant ◽

Alien Plant ◽

Vascular Plant Species

The highlands and mountains of Iceland are one of the largest remaining wilderness areas in Europe. This study aimed to provide comprehensive and up-to-date data on non-native plant species in these areas and to answer the following questions: (1) How many non-native vascular plant species inhabit highland and mountainous environments in Iceland? (2) Do temporal trends in the immigration of alien species to Iceland differ between highland and lowland areas? (3) Does the incidence of alien species in the disturbed and undisturbed areas within Icelandic highlands differ? (4) Does the spread of non-native species in Iceland proceed from lowlands to highlands? and (5) Can we detect hot-spots in the distribution of non-native taxa within the highlands? Overall, 16 non-native vascular plant species were detected, including 11 casuals and 5 naturalized taxa (1 invasive). Results showed that temporal trends in alien species immigration to highland and lowland areas are similar, but it is clear that the process of colonization of highland areas is still in its initial phase. Non-native plants tended to occur close to man-made infrastructure and buildings including huts, shelters, roads etc. Analysis of spatio-temporal patterns showed that the spread within highland areas is a second step in non-native plant colonization in Iceland. Several statically significant hot spots of alien plant occurrences were identified using the Getis-Ord Gi* statistic and these were linked to human disturbance. This research suggests that human-mediated dispersal is the main driving force increasing the risk of invasion in Iceland’s highlands and mountain areas.

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