The effect of the invasive Asclepias syriaca on the ground-dwelling arthropod fauna

Biologia ◽  
2015 ◽  
Vol 70 (1) ◽  
Author(s):  
Róbert Gallé ◽  
Nóra Erdélyi ◽  
Nikolett Szpisjak ◽  
Csaba Tölgyesi ◽  
István Maák

AbstractThe management of natural and seminatural systems often leads to disturbance associated with the appearance of non-native species. The spread of these species is increasing due to global environmental changes combined with local management interventions. These non-native species may establish self-sustaining populations influencing ecosystem functions, including the habitat use of native species. Here we explore the response of diplopods, spider and ant assemblages and the activity-density of individual species to the establishment of the non-native plant species, Asclepias syriaca in a disturbed poplar forest in Hungary. The relationship between the species richness of spiders and ants and the structural features of A. syriaca was weak. We found a significant relationship between the structural features of A. syriaca stands and the density and activity of the diplopod Megaphyllum unilineatum. We explain this relationship by the modified microclimate and litter quality of the habitats invaded by A. syriaca. The species composition of ant and spider assemblages was sensitive to A. syriaca. Asclepias syriaca had a negative local effect on the abundance of two spider species which were common in the studied forest. However, A. syriaca positively influenced the abundance of two ant species, most probably via indirect trophic relationships, as they feed on aphids living on A. syriaca. Our study shows that invasive plants can have mixed effects on local invertebrate assemblages. It is therefore crucial to understand how native assemblages respond to these changes in order to better manage these novel ecosystems and maximize their biodiversity benefits.

Author(s):  
Lohengrin A. Cavieres ◽  
◽  

Biological invasions are one the most important drivers of the current environmental changes generating important biodiversity losses. Although several hypotheses have been proposed to understand the mechanisms underpinning biological invasions, most of them relate to negative interactions among native and invasive species, where the capacity for many invasive species to reduce diversity is often attributed to a greater competitiveness. However, neighbouring species can also show facilitative interactions, where the presence of one species can facilitate another directly by improving environmental conditions or indirectly through negative effects on a third party species. This chapter reviews the scientific literature on plant invasion, seeking examples of where facilitative interactions either among native and non-native plant species or among non-native species were demonstrated. There are several examples of native species that directly facilitate a non-native species, while examples of native species having a negative effect either on a native or a non-native species that compete with a target non-native, generating a net indirect facilitative effect of the native on the target non-native, are less numerous. Direct facilitation among non-native species has been reported as part of the 'invasional meltdown' phenomenon (Chapter 8, this volume). There are cases where non-native species can have a negative effect on a native species that competes with a target non-native, generating a net indirect facilitative effect among the non-natives. Finally, a non-native species can have a direct facilitative effect on native species, which might have important implications in restoration.


Author(s):  
Lohengrin A. Cavieres

Abstract Biological invasions are one the most important drivers of the current environmental changes generating important biodiversity losses. Although several hypotheses have been proposed to understand the mechanisms underpinning biological invasions, most of them relate to negative interactions among native and invasive species, where the capacity for many invasive species to reduce diversity is often attributed to a greater competitiveness. However, neighbouring species can also show facilitative interactions, where the presence of one species can facilitate another directly by improving environmental conditions or indirectly through negative effects on a third party species. This chapter reviews the scientific literature on plant invasion, seeking examples of where facilitative interactions either among native and non-native plant species or among non-native species were demonstrated. There are several examples of native species that directly facilitate a non-native species, while examples of native species having a negative effect either on a native or a non-native species that compete with a target non-native, generating a net indirect facilitative effect of the native on the target non-native, are less numerous. Direct facilitation among non-native species has been reported as part of the 'invasional meltdown' phenomenon (Chapter 8, this volume). There are cases where non-native species can have a negative effect on a native species that competes with a target non-native, generating a net indirect facilitative effect among the non-natives. Finally, a non-native species can have a direct facilitative effect on native species, which might have important implications in restoration.


2011 ◽  
Vol 59 (7) ◽  
pp. 670 ◽  
Author(s):  
J. Dorrough ◽  
S. McIntyre ◽  
M. P. Scroggie

Livestock grazing and fertilisation are primary management activities that determine variation in plant species composition within grazed temperate grassy ecosystems of Australia. The present paper provides an extensive catalogue of the responses of individual species to grazing and fertilisation that can be used to guide management and restoration in differing situations. A hierarchical model that links plant species identities, simple plant traits and two continuous predictive variables (livestock density and available phosphorus) was used to estimate probability of occurrence of plant species across grazing and phosphorus gradients. Certain species and groups of species, particularly native perennial geophytes, ferns and shrubs, were especially sensitive to increases in each of these management gradients, whereas a small group of exotic plants were most tolerant. In the moderately intensive livestock production landscapes sampled, most native plant species preferred ungrazed areas with low available phosphorus. Many non-native plant species also tolerated or preferred such habitats. Less than 1% of all observed species are predicted to occur at high levels of available phosphorus (75 mg kg–1) and heavy stocking (9 dry sheep equivalents ha–1). There is, however, a suite of native species that persist at moderate livestock densities, but only if soils are not phosphorus-enriched. These data can be used to guide options for restoration including ranking of potential sites or selection of species for reintroduction. In most cases, livestock grazing intensity is thought to be the primary factor influencing plant species composition in grazed woodlands. These data, however, highlight the great importance of fertilisation history in limiting ground-layer plant diversity and determining options for management.


Author(s):  
Lohegrin A. Cavieres ◽  
◽  

Biological invasions are one the most important drivers of the current environmental changes generating important biodiversity losses. Although several hypotheses have been proposed to understand the mechanisms underpinning biological invasions, most of them relate to negative interactions among native and invasive species, where the capacity for many invasive species to reduce diversity is often attributed to a greater competitiveness. However, neighbouring species can also show facilitative interactions, where the presence of one species can facilitate another directly by improving environmental conditions or indirectly through negative effects on a third party species. This chapter reviews the scientific literature on plant invasion, seeking examples of where facilitative interactions either among native and non-native plant species or among non-native species were demonstrated. There are several examples of native species that directly facilitate a non-native species, while examples of native species having a negative effect either on a native or a non-native species that compete with a target non-native, generating a net indirect facilitative effect of the native on the target non-native, are less numerous. Direct facilitation among non-native species has been reported as part of the 'invasional meltdown' phenomenon (Chapter 8, this volume). There are cases where non-native species can have a negative effect on a native species that competes with a target non-native, generating a net indirect facilitative effect among the non-natives. Finally, a non-native species can have a direct facilitative effect on native species, which might have important implications in restoration.


Oecologia ◽  
2021 ◽  
Author(s):  
Jörg Bendix ◽  
Nicolay Aguire ◽  
Erwin Beck ◽  
Achim Bräuning ◽  
Roland Brandl ◽  
...  

AbstractTropical mountain ecosystems are threatened by climate and land-use changes. Their diversity and complexity make projections how they respond to environmental changes challenging. A suitable way are trait-based approaches, by distinguishing between response traits that determine the resistance of species to environmental changes and effect traits that are relevant for species' interactions, biotic processes, and ecosystem functions. The combination of those approaches with land surface models (LSM) linking the functional community composition to ecosystem functions provides new ways to project the response of ecosystems to environmental changes. With the interdisciplinary project RESPECT, we propose a research framework that uses a trait-based response-effect-framework (REF) to quantify relationships between abiotic conditions, the diversity of functional traits in communities, and associated biotic processes, informing a biodiversity-LSM. We apply the framework to a megadiverse tropical mountain forest. We use a plot design along an elevation and a land-use gradient to collect data on abiotic drivers, functional traits, and biotic processes. We integrate these data to build the biodiversity-LSM and illustrate how to test the model. REF results show that aboveground biomass production is not directly related to changing climatic conditions, but indirectly through associated changes in functional traits. Herbivory is directly related to changing abiotic conditions. The biodiversity-LSM informed by local functional trait and soil data improved the simulation of biomass production substantially. We conclude that local data, also derived from previous projects (platform Ecuador), are key elements of the research framework. We specify essential datasets to apply this framework to other mountain ecosystems.


2017 ◽  
Vol 9 (4) ◽  
pp. 86 ◽  
Author(s):  
Cristina A. Gómez-Moya ◽  
Talita P. S. Lima ◽  
Elisângela G. F. Morais ◽  
Manoel G. C. Gondim Jr. ◽  
Gilberto J. De Moraes

The expansion of red palm mite (RPM), Raoiella indica (Acari: Tenuipalpidae) in Brazil could impact negatively the native plant species, especially of the family Arecaceae. To determine which species could be at risk, we investigated the development and reproductive potential of R. indica on 19 plant species including 13 native species to the Brazilian Amazon (12 Arecaceae and one Heliconiaceae), and six exotic species, four Arecaceae, a Musaceae and a Zingiberaceae. Values of the instantaneous rate of increase (ri) were initially estimated at 7, 14, 21 and 28 days after infestation of each species. Higher values of ri (> 0.05) were determined on the Arecaceae Adonidia merrillii, Astrocaryum jauari, Cocos nucifera, Bactris simplicifrons, Mauritia flexuosa, Phoenix dactylifera and Socratea exorrhiza, and on the Heliconiaceae Heliconia psittacorum Sassy; these were classified as “potential primary hosts”. Lower, but still positive values of ri (0-0.05) were determined on the Arecaceae Bactris maraja, Oenocarpus bacaba, Oenocarpus bataua and on the Musaceae Musa × paradisiaca (Prata variety); these were classified as “potential secondary hosts”. Negative values of ri were determined for the remaining plants, i.e., the Arecaceae Astrocaryum aculeatum, Attalea maripa, Bactris gasipaes, Elaeis guineensis, Euterpe oleracea, Euterpe precatoria, and the Zingiberaceae Alpinia rosea; these were considered “non-hosts”. Species with ri < 0.05 were considered not to be threatened by the RPM. Biological parameters of RPM were evaluated on the plant species with positive ri (except B. maraja) and two native species with negative ri (E. oleracea and E. precatoria). Mean developmental time ranged from 14.7 days on C. nucifera to 21.4 days on Musa × paradisiaca, showing a significant influence of the plant substrate. Immature viability, oviposition rate, net reproductive rate (R0) and intrinsic rate of increase (rm) were affected by the plant species.


2016 ◽  
Vol 371 (1694) ◽  
pp. 20150269 ◽  
Author(s):  
Santiago Soliveres ◽  
Peter Manning ◽  
Daniel Prati ◽  
Martin M. Gossner ◽  
Fabian Alt ◽  
...  

Species diversity promotes the delivery of multiple ecosystem functions (multifunctionality). However, the relative functional importance of rare and common species in driving the biodiversity–multifunctionality relationship remains unknown. We studied the relationship between the diversity of rare and common species (according to their local abundances and across nine different trophic groups), and multifunctionality indices derived from 14 ecosystem functions on 150 grasslands across a land-use intensity (LUI) gradient. The diversity of above- and below-ground rare species had opposite effects, with rare above-ground species being associated with high levels of multifunctionality, probably because their effects on different functions did not trade off against each other. Conversely, common species were only related to average, not high, levels of multifunctionality, and their functional effects declined with LUI. Apart from the community-level effects of diversity, we found significant positive associations between the abundance of individual species and multifunctionality in 6% of the species tested. Species-specific functional effects were best predicted by their response to LUI: species that declined in abundance with land use intensification were those associated with higher levels of multifunctionality. Our results highlight the importance of rare species for ecosystem multifunctionality and help guiding future conservation priorities.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0237894
Author(s):  
Amy E. Kendig ◽  
Vida J. Svahnström ◽  
Ashish Adhikari ◽  
Philip F. Harmon ◽  
S. Luke Flory

Infectious diseases and invasive species can be strong drivers of biological systems that may interact to shift plant community composition. For example, disease can modify resource competition between invasive and native species. Invasive species tend to interact with a diversity of native species, and it is unclear how native species differ in response to disease-mediated competition with invasive species. Here, we quantified the biomass responses of three native North American grass species (Dichanthelium clandestinum, Elymus virginicus, and Eragrostis spectabilis) to disease-mediated competition with the non-native invasive grass Microstegium vimineum. The foliar fungal pathogen Bipolaris gigantea has recently emerged in Microstegium populations, causing a leaf spot disease that reduces Microstegium biomass and seed production. In a greenhouse experiment, we examined the effects of B. gigantea inoculation on two components of competitive ability for each native species: growth in the absence of competition and biomass responses to increasing densities of Microstegium. Bipolaris gigantea inoculation affected each of the three native species in unique ways, by increasing (Dichanthelium), decreasing (Elymus), or not changing (Eragrostis) their growth in the absence of competition relative to mock inoculation. Bipolaris gigantea inoculation did not, however, affect Microstegium biomass or mediate the effect of Microstegium density on native plant biomass. Thus, B. gigantea had species-specific effects on native plant competition with Microstegium through species-specific biomass responses to B. gigantea inoculation, but not through modified responses to Microstegium density. Our results suggest that disease may uniquely modify competitive interactions between invasive and native plants for different native plant species.


2020 ◽  
Author(s):  
Michael Joy ◽  
KJ Foote ◽  
P McNie ◽  
M Piria

© 2019 CSIRO. The number of New Zealand's freshwater fish listed as threatened has increased since 1992 when the first New Zealand threat classification system list was compiled. In this study, temporal and land cover-related trends were analysed for data on freshwater fish distribution, comprising more than 20 000 records for the 47 years from January 1970 to January 2017 from the New Zealand Freshwater Fish Database. The analysis included individual species abundance and distribution trends, as well as an index of fish community integrity, namely the Index of Biotic Integrity (IBI). Of the 25 fish species that met the requirements for analysis to determine changes in the proportion of sites they occupied over time, 76% had negative trends (indicating declining occurrence). Of the 20 native species analysed for the proportion of sites occupied over time, 75% had negative trends; 65% of these were significant declines and more species were in decline at pasture sites than natural cover sites. The average IBI score also declined over the time period and, when analysed separately, the major land cover types revealed that the IBI declined at pasture catchment sites but not at sites with natural vegetation catchments.


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