scholarly journals Dispersal syndromes can impact ecosystem functioning in spatially structured freshwater populations

2019 ◽  
Vol 15 (3) ◽  
pp. 20180865 ◽  
Author(s):  
Chelsea J. Little ◽  
Emanuel A. Fronhofer ◽  
Florian Altermatt
Keyword(s):  
Leaf Litter ◽  
Ecosystem Functioning ◽  
Native Species ◽  
Evolutionary Dynamics ◽  
Species Turnover ◽  
Freshwater Ecosystems ◽  
Dispersal Syndromes ◽  
Leaf Consumption ◽  
Litter Processing ◽  
Freshwater Habitats

Dispersal can strongly influence ecological and evolutionary dynamics. Besides the direct contribution of dispersal to population dynamics, dispersers often differ in their phenotypic attributes from non-dispersers, which leads to dispersal syndromes. The consequences of such dispersal syndromes have been widely explored at the population and community level; however, to date, ecosystem-level effects remain unclear. Here, we examine whether dispersing and resident individuals of two different aquatic keystone invertebrate species have different contributions to detrital processing, a key function in freshwater ecosystems. Using experimental two-patch systems, we found no difference in leaf consumption rates with dispersal status of the common native species Gammarus fossarum . In Dikerogammarus villosus , however, a Ponto-Caspian species now expanding throughout Europe, dispersers consumed leaf litter at roughly three times the rate of non-dispersers. Furthermore, this put the contribution of dispersing D. villosus to leaf litter processing on par with native G. fossarum, after adjusting for differences in organismal size. Given that leaf litter decomposition is a key function in aquatic ecosystems, and the rapid species turnover in freshwater habitats with range expansions of non-native species, this finding suggests that dispersal syndromes may have important consequences for ecosystem functioning.

scholarly journals Dispersal syndromes can impact ecosystem functioning in spatially structured freshwater populations

2018 ◽  
Author(s):  
Chelsea J. Little ◽  
Emanuel A. Fronhofer ◽  
Florian Altermatt
Keyword(s):  
Leaf Litter ◽  
Ecosystem Functioning ◽  
Native Species ◽  
Evolutionary Dynamics ◽  
Species Turnover ◽  
Freshwater Ecosystems ◽  
Dispersal Syndromes ◽  
Leaf Consumption ◽  
Litter Processing ◽  
Freshwater Habitats

Dispersal can strongly influence ecological and evolutionary dynamics. Besides the direct contribution of dispersal to population dynamics, dispersers often differ in their phenotypic attributes from non-dispersers, which leads to dispersal syndromes. The consequences of such dispersal syndromes have been widely explored at the population and community level, however, to date, ecosystem-level effects remain unclear. Here, we examine whether dispersing and resident individuals of two different aquatic keystone invertebrate species have different contributions to detrital processing, a key function in freshwater ecosystems. Using experimental two-patch systems, we found no difference in leaf consumption rates with dispersal status of the common native species Gammarus fossarum. In Dikerogammarus villosus, however, a Ponto-Caspian species now expanding throughout Europe, dispersers consumed leaf litter at roughly three times the rate of non-dispersers. Furthermore, this put the contribution of dispersing D. villosus to leaf litter processing on par with native G. fossarum, after adjusting for differences in organismal size. Given that leaf litter decomposition is a key function in aquatic ecosystems, and the rapid species turnover in freshwater habitats with range expansions of non-native species, this finding suggests that dispersal syndromes may have important consequences for ecosystem functioning.

scholarly journals Nonlinear Effects of Intraspecific Competition Alter Landscape-Wide Upscaling of Ecosystem Function

2018 ◽  
Author(s):  
Chelsea J. Little ◽  
Emanuel A. Fronhofer ◽  
Florian Altermatt
Keyword(s):  
Leaf Litter ◽  
Ecosystem Function ◽  
Intraspecific Competition ◽  
Interference Competition ◽  
Freshwater Ecosystems ◽  
Intraspecific Interactions ◽  
Negative Exponential Function ◽  
Density Dependent ◽  
Litter Processing ◽  
Leaf Litter Processing

AbstractA major focus of ecology is to understand and predict ecosystem function across scales. Many ecosystem functions are only measured at local scales, while their effects occur at a landscape level. Here, we investigate how landscape-scale predictions of ecosystem function depend on intraspecific competition, a fine-scale process, by manipulating intraspecific density of shredding macroinvertebrates and examining effects on leaf litter decomposition, a key function in freshwater ecosystems. Across two species, we found that leaf processing rates declined with increasing density following a negative exponential function, likely due to interference competition. To demonstrate consequences of this nonlinearity, we upscaled estimates of leaf litter processing from shredder abundance surveys in 10 replicated headwater streams. In accordance with Jensen’s inequality, applying density-dependent consumption rates reduced estimates of catchment-scale leaf consumption up to 60-fold versus using density-independent rates. Density-dependent consumption estimates aligned closely with metabolic requirements in catchments with large, but not small, shredder populations. Importantly, shredder abundance was not limited by leaf litter availability and catchment-level leaf litter supply was much higher than estimated consumption, thus leaf litter processing was not limited by resource supply. Our work highlights the need for upscaling which accounts for intraspecific interactions.

scholarly journals A modification of the leaf-bags method to assess spring ecosystem functioning: benthic invertebrates and leaf-litter breakdown in Vera Spring (Central Italy)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6250 ◽  
Author(s):  
Giovanni Cristiano ◽  
Bruno Cicolani ◽  
Francesco Paolo Miccoli ◽  
Antonio Di Sabatino
Keyword(s):  
Leaf Litter ◽  
Ecosystem Functioning ◽  
Central Italy ◽  
Freshwater Ecosystems ◽  
Freshwater Ecosystem ◽  
Litter Breakdown ◽  
Leaf Litter Breakdown ◽  
Detritus Processing ◽  
Stable Conditions ◽  
Leaf Bags

The evaluation of leaf detritus processing (decomposition and breakdown) is one of the most simple and cost-effective method to assess the functional characteristics of freshwater ecosystems. However, in comparison with other freshwater habitats, information on leaf litter breakdown in spring ecosystems is still scarce and fragmentary. In this paper, we present results of the first application of a variant of the leaf-bags method to assess structure of macroinvertebrate assemblages and leaf-litter breakdown in a Central Apennines (Italy) cold spring which was investigated from July 2016 to October 2016. Notwithstanding the stable conditions of almost all hydrological and physico-chemical parameters, we found significant temporal differences in (i) % of mass loss of poplar leaves (ii) number of Ephemeroptera, Plecoptera and Trichoptera taxa, (iii) shredder and predator densities. We demonstrate that detritus processing in cold springs may be faster than or as fast as in warmer streams/rivers. Shredders activity and biocoenotic interactions, rather than temperature and nutrients load, were the main drivers of the process. A routine application of the modified leaf-bags may contribute to expand our knowledge on detritus processing in cold springs and may help to predict impacts of climate warming on freshwater ecosystem functioning.

scholarly journals Dispersal syndromes affect ecosystem functioning in ciliate microcosms

2021 ◽  
Author(s):  
Allan Raffard ◽  
Julie Campana ◽  
Delphine Legrand ◽  
Nicolas Schtickzelle ◽  
Staffan Jacob
Keyword(s):  
Ecosystem Functioning ◽  
Evolutionary Dynamics ◽  
Phenotypic Variability ◽  
Intraspecific Variability ◽  
Biomass Productivity ◽  
Ecosystem Functions ◽  
Genotypic Effect ◽  
Phenotypic Differences ◽  
Dispersal Syndromes ◽  
Lower Biomass

AbstractDispersal is a key process mediating ecological and evolutionary dynamics. Its effects on metapopulations dynamics, population genetics or species range distribution can depend on phenotypic differences between dispersing and non-dispersing individuals (i.e., dispersal syndromes). However, scaling up to the importance of dispersal syndromes for meta-ecosystems have rarely been considered, despite intraspecific phenotypic variability is now recognised as an important factor mediating ecosystem functioning. In this study, we characterised the intraspecific variability of dispersal syndromes in twenty isolated genotypes of the ciliate Tetrahymena thermophila to test their consequences for biomass productivity in communities composed of five Tetrahymena species. To do so, dispersers and residents of each genotype were introduced, each separately, in ciliate communities composed of four other competing species of the genus Tetrahymena to investigate the effects of dispersal syndromes. We found that introducing dispersers led to a lower biomass compared to introducing residents. This effect was highly consistent across the twenty T. thermophila genotypes despite their marked differences of dispersal syndromes. Finally, we found a strong genotypic effect on biomass production, confirming that intraspecific variability in general affected ecosystem functions in our system. Our study shows that intraspecific variability and the existence of dispersal syndromes can impact the functioning of spatially structured ecosystems in a consistent and therefore predictable way.

Headwater reservoirs weaken terrestrial-aquatic linkage by slowing leaf-litter processing in downstream regulated reaches

2010 ◽  
Vol 28 (1) ◽  
pp. 13-22 ◽  
Author(s):  
C. Mendoza-Lera ◽  
A. Larrañaga ◽  
J. Pérez ◽  
E. Descals ◽  
A. Martínez ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Litter Processing ◽  
Leaf Litter Processing

Effect of Adult Tree Density and Nearness to the Natural Forest on the Restoration of Degraded Deciduous Forests of Attappady, Western Ghats, Kerala

2016 ◽  
Vol 39 (4) ◽  
pp. 309-315
Author(s):  
Ajithakumari Anusree ◽  
Puthiya Karunakaran ◽  
Narayanaswamy Parthasarathy
Keyword(s):  
Western Ghats ◽  
Native Species ◽  
Species Turnover ◽  
Tree Density ◽  
Natural Forest ◽  
Deciduous Forests ◽  
Tropical Deciduous Forest ◽  
Restoration Success ◽  
Adult Trees ◽  
Adult Tree

Studied on the effect of adult tree density and the proximity to the natural forest on restoration success in one of the most exploited tropical deciduous forests, Attappady, Western Ghats. Random quadrats were laid and surveyed for trees and saplings in remnant tropical deciduous forest patches (hereafter called as fragmented forest and the sites being restored here after called as restoration patches) to determine floristic composition, species turnover among sites and the influence of adult tree density on sapling density. Forests composed of deciduous and evergreen trees with an average species richness of 28 and alpha diversity of 2.671 in a 0.2 ha plot. Similarity of restoration patches with natural forest increased as distance between them decreased and regeneration of native species were more efficient in sites with more number of adult trees. Local (adult tree density) and landscape level (isolation of patches) factors are both important in determining the restoration success of deciduous forests of Attappady.

Free-living freshwater nematodes from Brazil: checklist of genera and regional patterns of diversity

Nematology ◽  
2021 ◽  
pp. 1-14
Author(s):  
Taciana Kramer de Oliveira Pinto ◽  
Sérgio A. Netto ◽  
André Morgado Esteves ◽  
Francisco José Victor de Castro ◽  
Patricia Fernandes Neres ◽  
...  
Keyword(s):  
Benthic Communities ◽  
Extreme Environments ◽  
Freshwater Ecosystems ◽  
Freshwater Biodiversity ◽  
High Turnover ◽  
Free Living ◽  
Regional Patterns ◽  
Freshwater Nematodes ◽  
Spatial Coverage ◽  
Freshwater Habitats

Summary Brazil has one of the largest varieties of aquatic ecosystems and rich freshwater biodiversity, but these components have constantly been damaged by the expansion of unsustainable activities. Free-living nematodes are an abundant and ubiquitous component of continental benthic communities, occurring in all freshwater habitats, including extreme environments. Despite this, hardly any studies have examined the generic composition of nematodes in different latitudes and the geographic overlap of assemblages. We provide data on nematode genera from six regions in Brazil, over a north-south gradient spanning about 4000 km, encompassing rivers, coastal lakes, and reservoirs with different levels of human impact. Interpolation/extrapolation curves were generated and the zeta diversity was used to assess the overlap of nematode assemblages. Freshwater nematode assemblages comprised 54 families and 132 genera. Mononchidae, Monhysteridae, Chromadoridae, Tobrilidae and Dorylaimidae were the most diverse families. Differences in diversity and high turnover of genera were found among regions, probably related to stochastic processes. Mononchus was the only widely distributed genus. Our results revealed a high biodiversity of free-living freshwater nematodes among the regions. The limited spatial coverage of the data reveals an enormous knowledge gap in a country with 12% of the world’s freshwater resources. The lack of spatial patterns, e.g., latitudinal variation, suggests that freshwater nematode assemblages are primarily structured by the intrinsic properties of habitats. This reinforces the uniqueness of freshwater ecosystems and suggests that the nematode assemblages may be sensitive to environmental disturbances, since the limited distributions of taxa may lead to lower resilience.

scholarly journals The conservation value of South East Asia's highly degraded forests: evidence from leaf-litter ants

2011 ◽  
Vol 366 (1582) ◽  
pp. 3256-3264 ◽  
Author(s):  
Paul Woodcock ◽  
David P. Edwards ◽  
Tom M. Fayle ◽  
Rob J. Newton ◽  
Chey Vun Khen ◽  
...  
Keyword(s):  
Species Richness ◽  
Leaf Litter ◽  
Oil Palm ◽  
Species Turnover ◽  
Spatial Scales ◽  
Forest Conversion ◽  
Conservation Value ◽  
Natural Forests ◽  
Ant Communities ◽  
Logged Forest

South East Asia is widely regarded as a centre of threatened biodiversity owing to extensive logging and forest conversion to agriculture. In particular, forests degraded by repeated rounds of intensive logging are viewed as having little conservation value and are afforded meagre protection from conversion to oil palm. Here, we determine the biological value of such heavily degraded forests by comparing leaf-litter ant communities in unlogged (natural) and twice-logged forests in Sabah, Borneo. We accounted for impacts of logging on habitat heterogeneity by comparing species richness and composition at four nested spatial scales, and examining how species richness was partitioned across the landscape in each habitat. We found that twice-logged forest had fewer species occurrences, lower species richness at small spatial scales and altered species composition compared with natural forests. However, over 80 per cent of species found in unlogged forest were detected within twice-logged forest. Moreover, greater species turnover among sites in twice-logged forest resulted in identical species richness between habitats at the largest spatial scale. While two intensive logging cycles have negative impacts on ant communities, these degraded forests clearly provide important habitat for numerous species and preventing their conversion to oil palm and other crops should be a conservation priority.

scholarly journals Alien Species vs. Native Species: From Community Ecology to Eco-Evolutionary Dynamics

2019 ◽  
Author(s):  
Andersonn Silveira Prestes
Keyword(s):  
Alien Species ◽  
Exotic Species ◽  
Native Species ◽  
Evolutionary Dynamics ◽  
Evolutionary Processes ◽  
Native Communities ◽  
Individualized Approach ◽  
History Of ◽  
Relationship Of ◽  
The Relationship

The establishment and spread of exotic species is a contemporary major concern. Alien species may become invasive in their new habitat, leading to both/either environmental and/or economic impacts. I briefly reviewed the literature in the last decade about the relationship of exotic species and native communities. I identified that professionals usually approach the subject in two main points of view: (1) researchers tend to point out the impacts of alien species on entire communities, evaluating if the relationship is positive, negative or neutral; (2) they focus on the eco-evolutionary processes involved in the introductions, the dynamics of invasion, and individual study cases. When evaluating the response of introductions to entire communities, evidence seems to be ambiguous and may support positive, negative or neutral relationship, especially depending on the scale approached. The unique eco-evolutionary pathways of each introduction may be a great shortcoming in the searching for generalities. On the other hand, advances have been made in understanding the dynamics of invasion on different lineages through a more selective/individualized approach. I suggest that the dynamics of invasion might be studied through a perspective in which different eco-evolutionary processes, levels of organization (from gene to entire communities), the history of the organism(s) and time are taken into account. Individual cases might be compared in attempt to understand how the relationship exotic and native works and in the search for generalities.

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