PaperPlayer biorxiv ecology

Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.13.249896v1?rss=1

Authors: Cordone, G., Lozada, M., Vilacoba, E., Thalinger, B., Bigatti, G., Lijtmaer, D., Steinke, D., Galvan, D. E.

Abstract:

The European green crab Carcinus maenas and, its sister species, C. aestuarii are highly invasive species causing damages to coastal ecosystems and severe economic losses worldwide. C. maenas was detected at the Atlantic Patagonian coast twenty years ago. In this work, we studied the diet of the green crab in a recently invaded location in Nuevo Gulf, using three complementary techniques: direct stomach observation, stable isotope analysis, and metabarcoding of the gut content. Direct stomach observation and metabarcoding showed that green crabs have a broad omnivorous diet, ingesting most of the phyla present in the study area. Gut content metabarcoding allowed a detailed description of algae diversity and revealed other taxa that went unnoticed in the visual stomach analysis. Stable isotope analysis showed that the major contribution to crabs' diet was from the phytoplankton chain (by bivalve consumption) and not directly from algae. This study approach combining three complementary techniques allowed us to detect some differences in the diet between sexes, which suggests that male and female crabs are not as ecologically equivalent as previously thought. Besides, we detected sequences corresponding to C. aestuarii suggesting that the green crab Patagonian population is a hybrid of both sister species. Finally, we highlight possible direct and indirect interactions of the green crab with the native species that can trigger negative effects throughout the entire food web.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.13.248849v1?rss=1

Authors: Duchesneau, K., Madeira Antunes, P., Colautti, R. I., Golemiec, A.

Abstract:

Soil feedback is thought to be an important contributor to the success of invasive plants. Despite evidence that invasive plants change soil microbial diversity, the functional roles of microbes impacted by invasion are still unclear. This knowledge is a critical component of our understanding of ecological mechanisms of plant invasion. Mounting evidence suggests Alliaria petiolata can suppress arbuscular mycorrhizal fungi (AMF) to disrupt native plant communities in controlled laboratory and greenhouse experiments, though it is less clear if allelochemicals persist under natural field conditions. Alternatively, invasive plants may accumulate pathogens that are more harmful to competitors as predicted by the Enemy of my Enemy Hypothesis (EEH). We examined changes in functional groups of soil bacteria and fungi associated with ten naturally occurring populations of A. petiolata using amplicon sequences (16S and ITS rRNA). To relate soil microbial communities to impacts on co-occurring plants, we measured root infections and AMF colonization. We found no changes in the diversity and abundance of AMF in plants co-occurring with A. petiolata, suggesting that mycorrhizal suppression in the field may not be as critical to the invasion of A. petiolata as implied by more controlled experiments. Instead, we found changes in pathogen community composition and marginal evidence of increase in root lesions of plants growing with A. petiolata, lending support to the EEH. In addition to these impacts on plant health, changes in ectomycorrhiza, and other nutrient cycling microbes may be important forces underlying the invasion of A. petiolata and its impact on ecosystem function.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.13.248831v1?rss=1

Authors: Rizzuto, M., Leroux, S., Vander Wal, E., Richmond, I. C., Heckford, T. R., Balluffi-Fry, J., Wiersma, Y. F.

Abstract:

Consumers make space use decisions based on resource quality. Most studies that investigate the influence of resource quality on the spatial ecology of consumers use diverse proxies for quality including measures based on habitat classification, forage species diversity and abundance, and nutritional indicators, e.g., protein. Ecological stoichiometry measures resource quality in terms of elemental ratios, e.g., carbon (C):nitrogen (N) ratio, but rarely have these currencies been used to study consumer space use decisions. Yet, elemental ratios provide a uniquely quantitative way to assess resource quality. Consequently, ecological stoichiometry allows for investigation of how consumers respond to spatial heterogeneity in resource quality by changing their space use, e.g. their home range size, and how this may influence ecosystem dynamics and trophic interactions. Here, we test whether the home range size of a keystone boreal herbivore, the snowshoe hare (Lepus americanus), varies with differences in the C:N, C:phosphorus (P), and N:P ratios of two preferred forage species, lowland blueberry (Vaccinium angustifolium) and red maple (Acer rubrum). We consider forage resources with higher C content relative to N and P to be lower quality than resources with lower relative C content. We use a novel approach, combining elemental distribution models with herbivore home range size estimates to test our hypothesis that hare home range size will be smaller in areas with access to high, homogeneous resource quality compared to areas with access to low, heterogeneous resource quality during summer months. Our results support our prediction for lowland blueberry, but not for red maple. Herbivore home range size decreased with increasing blueberry foliage quality, but also with decreasing spatial heterogeneity in blueberry foliage quality, i.e. N or P content. Herbivores in the boreal forest face strong nutritional constraints due to the paucity of N and P. Access to areas of high, homogeneous resource quality is paramount to meeting their dietary requirements with low effort. In turn, this may influence community (e.g., trophic interactions) and ecosystem (e.g., nutrient cycling) processes. Paradoxically, our study shows that taking a reductionist approach of viewing resources through a biochemical lens can lead to holistic insights of consumer spatial ecology.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.13.248237v1?rss=1

Authors: Tiruvaimozhi, Y. V., Bagchi, S., Sankaran, M.

Abstract:

Arbuscular mycorrhizal fungal (AMF) symbioses with plants can be influenced by top-down forces such as grazing, and also by bottom-up forces such as soil resource availability, both of which are being altered by anthropogenic and global change drivers. While the influence of each of these factors on AMF symbioses has been widely studied, explicit tests of the relative strengths of top-down versus bottom-up influences on these ubiquitous plant root symbioses are few. We studied AMF colonization responses of four species of graminoids (3 grasses Elymus longae-aristatus, Leymus secalinus and Stipa orientalis, and a sedge Carex melanantha) common to semiarid high-altitude rangelands of the Spiti region, Trans-Himalaya, to changes in a top-down driver, grazing intensity (through short-term clipping and long-term grazer exclusion experiments), and a bottom-up driver, water availability (using irrigation treatments, and by evaluating responses to annual precipitation levels across years). Over three years, AMF colonization in all four host species was influenced by precipitation, with the highest and lowest AMF colonization levels corresponding to years with the lowest and highest rainfall, respectively. However, responses to long-term grazer exclusion differed among host species, and across years: while some species showed decreases in AMF colonization levels under grazing, others showed increases from ungrazed control levels, and these responses changed, even reversed, across years. Responses to short-term clipping and irrigation treatments also differed among hosts, with some species responding to irrigation alone, some to clipping and irrigation combined, and others showing no changes in AMF colonization from control levels in any of the treatments. In our study, long-term changes in water availability influenced AMF colonization levels, while short-term responses were host specific. Responses to above-ground tissue loss, however, differed among host species both in the long- and short-term. Overall, this study demonstrates that while AMF colonization levels correspond to annual precipitation levels in this semiarid ecosystem, host species also play a role in influencing plant-AMF interactions in these rangelands, with colonization levels and responses to abiotic factors changing with host species.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.13.249151v1?rss=1

Authors: Munden, R., Borger, L., Wilson, R. P., Redcliffe, J., Brown, R., Garel, M., Potts, J. R.

Abstract:

Step selection analysis (SSA) is a fundamental technique for uncovering the drivers of animal movement decisions. Its typical use has been to view an animal as ''selecting'' each measured location, given its current (and possibly previous) locations. Although an animal is unlikely to make decisions precisely at the times its locations are measured, if data are gathered at a relatively low frequency (every few minutes or hours) this is often the best that can be done. Nowadays, though, tracking data is increasingly gathered at very high frequencies, e.g. >1Hz, so it may be possible to exploit these data to perform more behaviourally-meaningful step selection analysis. Here, we present a technique to do this. We first use an existing algorithm to determine the turning-points in an animal's movement path. We define a ''step'' to be a straight-line movement between successive turning-points. We then construct a generalised version of integrated SSA (iSSA), called time-varying iSSA (tiSSA), which deals with the fact that turning-points are usually irregularly spaced in time. We demonstrate the efficacy of tiSSA by application to data on free-ranging goats (Capra aegagrus hircus), comparing our results to those of regular iSSA with locations that are separated by a constant time-interval. Using (regular) iSSA with constant time-steps can give results that are misleading compared to using tiSSA with the actual turns made by the animals. Furthermore, tiSSA can be used to infer covariates that are dependent on the step-time, which is not possible with regular iSSA. As an example, we show that our study animals tend to spend less time between successive turns when the ground is rockier and/or the temperature is hotter. By constructing a step selection technique that works between observed turning-points of animals, we enable step selection to be used on high-frequency movement data, which are becoming increasingly prevalent in modern biologging studies. Furthermore, since turning-points can be viewed as decisions, our method places step selection analysis on a more behaviourally-meaningful footing compared to previous techniques.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.12.248948v1?rss=1

Authors: Woodell, J. D., Neiman, M., Levri, E. P.

Abstract:

Early detection of invasive species allows for a more rapid and effective response. Restoration of the native ecosystem after an invasive population has established is expensive and difficult but more likely to succeed when invasions are detected early in the invasion process. Containment efforts to prevent the spread of known invasions also benefit from earlier knowledge of invaded sites. Environmental DNA (eDNA) techniques have emerged as a tool that can identify invasive species at a distinctly earlier time point than traditional methods of detection. Due to expected range expansion in eastern North America, we focus on the destructive New Zealand Mud Snail Potamopyrgus antipodarum (NZMS) invasion. We collected water samples from eight sites that prior evidence indicated were not yet invaded by the NZMS. After filtering these samples to collect eDNA, we used a species-specific probe with qPCR to identify NZMS eDNA. We found evidence for NZMS invasion at five of the eight sites, with later physical confirmation of mud snails at one of these sites. This study is the first example of successful detection of a previously unidentified invasive population of NZMS, setting the stage for further monitoring of at-risk sites to detect and control new invasions of this destructive snail. This study also shows potential opportunities for invasion monitoring offered by using low-cost efforts and methods that are adaptable for citizen science.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.12.247502v1?rss=1

Authors: Balbuena, J. A., Montlleo, C., Llopis-Belenguer, C., Blasco-Costa, I., Sarabeev, V. L., Morand, S.

Abstract:

1. Most species in ecological communities are rare whereas only a few are common. This distributional paradox has intrigued ecologists for decades but the interpretation of species abundance distributions remains elusive. 2. We present Fuzzy Quantification of Common and Rare Species in Ecological Communities (FuzzyQ) as an R package. FuzzyQ shifts the focus from the prevailing species-categorization approach to develop a quantitative framework that seeks to place each species along a rare-commonness gradient. Given a community surveyed over a number of sites, quadrats, or any other convenient sampling unit, FuzzyQ uses a fuzzy clustering algorithm that estimates a probability for each species to be common or rare based on abundance-occupancy information. Such as probability can be interpreted as a commonness index ranging from 0 to 1. FuzzyQ also provides community-level metrics about the coherence of the allocation of species into the common and rare clusters that are informative of the nature of the community under study. 3. The functionality of FuzzyQ is shown with two real datasets. We demonstrate how FuzzyQ can effectively be used to monitor and model spatio-temporal changes in species commonness, and assess the impact of species introductions on ecological communities. We also show that the approach works satisfactorily with a wide range of communities varying in species richness, dispersion and abundance currencies. 4. FuzzyQ produces ecological indicators easy to measure and interpret that can give both clear, actionable insights into the nature of ecological communities and provides a powerful way to monitor environmental change on ecosystems. Comparison among communities is greatly facilitated by the fact that the method is relatively independent of the number of sites or sampling units considered. Thus, we consider FuzzyQ as a potentially valuable analytical tool in community ecology and conservation biology.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.13.249227v1?rss=1

Authors: Issimov, A., Kutumbetov, L., Zhanabayev, A., Kazhgaliyev, N., Nurgaliyev, B., Zhubantayev, I., Akhmetaliyeva, A., Shalmenov, M., Kereyev, A., White, P. J.

Abstract:

Lumpy skin disease (LSD) is an emerging disease in cattle in Kazakhstan and the means of transmission remains uncertain. In the current study, acquisition of Lumpy Skin Disease Virus (LSDV) by Stomoxys species following intrathoracic inoculation was demonstrated under laboratory conditions. Flies were injected with a virulent LSDV strain into the thorax region to bypass the midgut barrier. The fate of pathogen in the hemolymph of the flies was further examined using PCR and Virus isolation tests. LSDV was isolated from all three Stomoxys species immediately and up to 24h post intrathoracic inoculation while virus DNA was detectable up to 7d post intrathoracic inoculation.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.11.246991v1?rss=1

Authors: Nunez-Penichet, C., Osorio-Olvera, L., Gonzalez, V. H., Cobos, M. E., Jimenez, L., DeRaad, D. A., Alkishe, A., Contreras-Diaz, R., Nava-Bolanos, A., Utzumi, K., Ashraf, U., Adeboje, A., Peterson, A. T., Soberon, J.

Abstract:

The Asian giant hornet (AGH, Vespa mandarinia) is the world largest hornet, occurring naturally in the Indomalayan region, where it is a voracious predator of pollinating insects including honey bees. In September 2019, a nest of Asian giant hornets was detected outside of Vancouver, British Columbia and in May 2020 an individual was detected nearby in Washington state, indicating that the AGH successfully overwintered in North America. Because hornets tend to spread rapidly and become pests, reliable estimates of the potential invasive range of V. mandarinia in North America are needed to assess likely human and economic impacts, and to guide future eradication attempts. Here, we assess climatic suitability for AGH in North America, and suggest that, without control, this species could establish populations across the Pacific Northwest and much of eastern North America. Predicted suitable areas for AGH in North America overlap broadly with areas where honey production is highest, as well as with species-rich areas for native bumble bees and stingless bees of the genus Melipona in Mexico, highlighting the economic and environmental necessity of controlling this nascent invasion.

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Link to bioRxiv paper:

http://biorxiv.org/cgi/content/short/2020.08.11.246629v1?rss=1

Authors: Masier, S., Dahirel, M., Mortier, F., Bonte, D.

Abstract:

Habitat fragmentation reduces the area of habitat patches and their connectedness in the landscape. It is well established that the level of connectedness impacts connectivity and metapopulation dynamics, and is therefore a central tenet in conservation biology. Connectedness equally generates sorting of phenotypes within the spatial network and therefore impacts local and regional eco-evolutionary dynamics. Paradoxically, recommendations for species conservation rely on principles derived from theory that neglects any individual phenotypic heterogenety and spatial organization. By creating experimental metapopulations using the model species Tetranychus urticae (two-spotted spider mite) with three levels of landscape connectedness and by regularly removing phenotypic structure in a subset of these populations, we tested the degree to which regional and local population dynamics are determined both by network connectedness and the phenotypic spatial organization. Our results show that some aspects of metapopulation dynamics can be attributed to the evolution of dispersal. More importantly, we find self-organization of phenotypic spatial structure to equalize the effects of reduced connectedness on metapopulation dynamics. These changes were all in the direction of improved metapopulation persistence. Contrary to expectations, the most connected local patches showed an overall reduced local population size, possibly originating from a faster depletion of resources from immigrants or transiting individuals. This experiment shows how metapopulation dynamics can significantly deviate from theoretical expectations if individual heterogeneity is considered, and more importantly that disruption of this phenotypic self-structuring may drive metapopulation dynamics towards higher risks of extinction.

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