Determination of Yield and Botanical Composition of the Meadow and Grassland in Çolpan Village at the Shores of Lake Van

This study was carried out at the meadows and pastures in Çolpan village of Van province in 2020. In the study, matter yield, botanical composition, plant covered area, rate of decreaser/increaser/invader species were determined. The Loop method was used to determine the botanical composition. In grassland area were identified 69 species belonging to 17 families. In meadow area were identified 20 species belonging to 6 families. The amount of Poaceae, Fabaceae and other families found in the grassland area were determined as 18.66%, 15.65%, and 65.69%, respectively. In the meadow area, the amount of Poaceae, Fabaceae and other families were determined as 67.50%, 15.0%, and 17.50%, respectively. Artemisia spicigera (4.74%) Taeniatherum caput-medusae (5.0%) Arenaria serpyllifolia (5.0%) Medicago monantha (5.92%) species were the most common species found in the grassland area. Hordeum brevisubulatum (25.5%), Bromus scoparius (16.75%), and Taraxacum androssovii (9.25%) species were the most common species found in the meadow area. According to the ratio of good plants, pasture was classified as poor pasture and meadow was in the moderate meadow class. Grassland and meadow matter yields were found to be 91.4 kg/da and 385.2 kg/da, respectively. In the grassland of Çolpan village, invader species were found to be dense. It was concluded that grassland area should be improved.

Urban landscape selection by Eurasian collared dove (Streptopelia decaocto) in eastern Spain

The Eurasian collared dove (Streptopelia decaocto) is an invader species, and its distribution is continuously on the increase. Today its expansion has spread to the American continent. In this study we describe the effects of the urban environment on the Eurasian collared dove in eastern Spain. The abundance and presence of this dove were analyzed in 46 localities using counting points. Overall, 220-point counts were surveyed between autumn 2015 and late-winter 2016. A hierarchical partitioning analysis was used to identify explanatory variables of different types such as resources, climate and urban structure, and human presence, which may influence the presence and abundance of this species. In the case of presence, the number of town inhabitants, parks, mean minimum temperature, exotic vegetation and schools had a positive association, while pedestrian number and restaurants had a negative association. Abundance was positively related to native vegetation, exotic vegetation, and water, while urban area was negatively associated with it. Exotic vegetation was the only variable that has a positive relation to presence and abundance. These results can help to predict the use of urban habitats in potential localities for its invasion.

Recent fire activity in the boreal forests of central western Siberia is unprecedented in the past 5000 years: palaeoenvironmental evidence contextualises a burning issue

<p>Although wildfire events in Siberia have increased in frequency and intensity over recent decades, in the absence of long-term records, it is not clear how far this trend deviates from baseline conditions. Short-term datasets categorise the forest fire regime in Siberia as one of surface, litter fires alternating withdevastating crown fires, although there is significant variability within this region likely reflecting vegetation composition. However, a comprehensive understanding of how vegetation composition and properties determine fire regimes remains lacking. To address this question we used two peat records spanning the last 2500 yr and a 5000 yr, respectively of charcoal morphologies-derived fire regime, pollen-based vegetation dynamics and stable isotope and testate amoebae-based climate reconstructions from boreal forests in central western Siberia, combined with fire-related functional traits of key boreal tree species. Compared to the trend over the 5000 yr period (mean fire return interval=FRI of 400 yr), our reconstructed mean FRI of 145 yr for the last five centuries is notably the shortest in the record. Most fires in this area tend to be surface, litter fires, although over the last centuries surface fires show an increased trend towards crowning. Frequent fires between 5000 and 4000 cal yr BP and 1500 cal yr BP to the present were concurrent with the dominance of invader species (primarily Betula) and fire endurer (mainly herbs) with prevalence of resisters (Pinus sylvestris, Pinus sibirica). Longer fire return intervals (up to 500 yr) between 4000 and 1500 cal yr BP were associated with the dominance of fire resisters with a considerable proportion of fire avoiders (Abies sibirica and Picea obovata). The rising number of fire episodes and the intensification of fire events over the past 1500 years have likely promoted fire-adapted plant communities (invaders and endurers) that can rapidly reach maturity, contributing to the reduction of avoider and resister species. This trend demonstrates that fire avoider species particularly fail to regenerate if the intervals between fire episodes are too short and thatan increasing number of fire episodes can drive land cover towards more fire-adapted plant communities. Our long-term perspective shows that the current fire regime lies significantly outside baseline conditions, which may drive future change in forest composition towards an increased prevalence of invader species. This study also contributes to an understanding of disturbance regimes in Pinus-Betula forests and considers the potential of tree species to adapt to new fire regimes.</p><p> </p>

Transient invaders can induce shifts between alternative stable states of microbial communities

Microbial dispersal often leads to the arrival of outsider organisms into ecosystems. When their arrival gives rise to successful invasions, outsider species establish within the resident community, which can markedly alter the ecosystem. Seemingly less influential, the potential impact of unsuccessful invaders that interact only transiently with the community has remained largely ignored. Here, we experimentally demonstrate that these transient invasions can induce a lasting transition to an alternative stable state, even when the invader species itself does not survive the transition. First, we develop a mechanistic understanding of how environmental changes caused by these transient invaders can drive a community shift in a simple, bistable model system. Beyond this, we show that transient invaders can also induce switches between stable states in more complex communities isolated from natural soil samples. Our results demonstrate that short-term interactions with an invader species can induce lasting shifts in community composition and function.

Transient invaders can induce shifts between alternative stable states of microbial communities

Microbial dispersal often leads to the arrival of outsider organisms into ecosystems. When their arrival give rise to successful invasions, outsider species establish within the resident community, which can dramatically alter the ecosystem. Seemingly less influential, the potential impact of unsuccessful invaders that interact only transiently with the community has remained largely ignored. Here, we experimentally demonstrate that such transient invasions can perturb the stability of microbial ecosystems and induce a lasting transition to an alternative stable state, even when the invader species itself does not survive the transition. First, we develop a mechanistic understanding of how environmental changes caused by such transient invaders can drive a community shift in a simple, bistable model system. Beyond this, we show that transient invaders can also induce switches between stable states in more complex communities isolated from natural soil samples. Our results demonstrate that short-term interactions with an invader species can induce lasting shifts in community composition and function.One Sentence SummaryTransient invaders can cause lasting shifts in community composition and function.

Diagnosis, presence of endoparasites, and local knowledge on the infestation of the exotic giant African snail (gastropoda: pulmonata: achatinidae), in the urban zone of Rio Branco, Acre, Brazil

The giant African land snail, Lissachatina fulica is considered to be one of the world's worst invader species. This snail can provoke major economic and public health problems in urban areas, in particular as a potential vector of nematodes that infect both humans and animals. In this context, the present study investigated the extent of the infestation of this exotic snail in the urban neighborhoods of the city of Rio Branco, verified the presence of endoparasites in these snails, and evaluated the knowledge of local residents with regard to the presence of this invader species. For this, daytime surveys were conducted between August 2015 and June 2016. For the analysis of endoparasites, 44 live specimens were sent to the National Reference Laboratory for Schistosomiasis-Malacology (LRNEM) of the Oswaldo Cruz Institute (FIOCRUZ). The knowledge of local residents in the infested neighborhoods was investigated using questionnaires with direct, closed questions. The exotic invader species (L. fulica) was detected in 24 of the 36 neighborhoods visited. A total of 858 L. fulica specimens were collected, of which, 329 were alive and 527 were dead. The total length of the shell ranged from 0.7 to 14.2 cm, with a mean±standard deviation of 4.8±2.21 cm. The density of snails in the areas surveyed varied from 0.34 individuals/m2 to 3.54 individuals/m2, while the mean density within the whole study area was estimated to be 0.54 individuals/m2. Mature eggs were found in only 9 (2.7%) of the 329 specimens dissected. The endoparasitological analysis revealed the presence of rhabditiform larvae in 84% of the specimens examined, as well as the nematodes Aelurostrongylus abstrusus (22.7% of the specimens) and Strongyluris sp. (2.2%). A total of 39 local residents were interviewed, and while all were conscious of the presence of the mollusk, none knew its origin or the most adequate way of dealing with it. The results of the study indicate an ample infestation of the city of Rio Branco by L. fulica, and confirmed a complete lack of intervention on the part of the local authorities for the implementation of measures foe the control and management of this pest within the urban zone of Rio Branco.

Can the mother plant age of Acacia melanoxylon (Leguminosae) modulate the germinative response to fire?

Acacia melanoxylon R.Br. (Leguminosae) is one of the most widely distributed tree species in the world. It has significant commercial use but can be a danger to natural ecosystems as an invader species. For these reasons it is necessary to have a deep knowledge about its germinative response to fire and the role the mother plant age plays in that response. In this work we assessed the effects of the interaction of the mother plant age with the main fire agents (smoke, charcoal, ash and heat) on the germinative response of A. melanoxylon. To reach this aim, germination tests were conducted with seeds from young, intermediate and mature mother plants, with 20 treatments each applied. Results show that fire can act as a great stimulator of the germination of A. melanoxylon but it can also strongly inhibit it. The mother plant age does not modify the final germination values, but it influences the time in which the first germinations occur after fire. This trait can be more important than the final germination percentage when looking at the success of post-fire regeneration. These results have important implications for A. melanoxylon management, for both species control and ecological restoration purposes.

Bioinvasion of Tradescantia zebrina Heynh. (Commelinaceae) in uplands, State of Paraíba, Brazil

The study of invader species and their consequences to the environment represents an important reinforcement to the knowledge of environmental preservation. This work aimed to evaluate the invasive aspects of Tradescantia zebrina Heynh., subsidizing information to their adequate management or control. The study area is compound by a Open Ombrophylous Forest in the Municipality of Areia, Paraíba State, Brazil. The evaluated variables were populational density, biomass, biometry, invasion velocity and impacts of species under resilience of native vegetation. The results found density of 627 +/- 16 individuals/m2, (mean +/- standard deviation), 25.9 +/- 68 cm length and 0.21 +/- 0.03 cm de diameter with positive relationship between both variables (r = 0.24; t = 2.4; p = 0.02) and biomass of 16.9 g (leaves), 10.6 g (stems) and 1.3 g (roots) for each 100 sampled individuals, being that in each m2, reached to have 18.8 +/- 5,1 g leaf biomass, 22.4 +/- 7.6 g stem biomass and 3.4 +/- 1.3 g root biomass. The population showed a rapid expansion occupying 0.30 +/- 0.09 m2 after seven days and 0.51 +/- 0.15 m2 in eighty four days. Parcels without the invader species (SE) showed expansive accumulation of individuals throughout the evaluation time, while in the parcels with the species (CE) the number of individuals exhibit few changes (p = 0.021 and H = 5.327). The results exhibit the biological invasion in the UFPB Campus II by T. zebrina, represents a threat to the local biodiversity due to its aggressive invasive behavior.