spatial overlap
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Author(s):  
Phoebe Parker‐Shames ◽  
Christopher Choi ◽  
Van Butsic ◽  
David Green ◽  
Brent Barry ◽  
...  

2021 ◽  
Author(s):  
Marie E Hardouin ◽  
Anna L Hargreaves

Protecting habitat of species-at-risk is critical to their recovery, but can be contentious. For example, protecting species that are locally imperilled but globally common (e.g. species that only occur in a jurisdiction at the edge of their geographic range) is often thought to distract from protecting globally-imperilled species. However, such perceived trade-offs are based on the assumption that threatened groups have little spatial overlap, which is rarely quantified. Here, we compile range maps of terrestrial species-at-risk in Canada to assess the geographic overlap of nationally and globally at-risk species with each other, among taxonomic groups, and with protected areas. While many nationally-at-risk taxa only occurred in Canada at their northern range edge (median=4% of range in Canada), nationally-at-risk species were not significantly more peripheral in Canada than globally-at-risk species. Further, 56% of hotspots of nationally-at-risk taxa were also hotspots of globally-at-risk taxa in Canada, undercutting the perceived trade-off in their protection. Hotspots of nationally-at-risk taxa also strongly overlapped with hotspots of individual taxonomic groups, though less so for mammals. While strong spatial overlap across threat levels and taxa should facilitate efficient habitat protection, <7% of the area in Canada's at-risk hotspots is protected, and more than 70% of nationally and globally-at-risk species in Canada have <10% of their Canadian range protected. Our results counter the perception that protecting nationally vs. globally at-risk species are at odds, and identify critical areas to target as Canada strives to increase its protected areas and promote species-at-risk recovery.


2021 ◽  
Vol 9 (12) ◽  
pp. 2447
Author(s):  
Philippe Le Noac’h ◽  
Vincent Ouellet Jobin ◽  
Beatrix E. Beisner

In phytoplankton communities, competitive exclusion might occur when functionally similar species are impeded from regulating their positions along light and nutrient gradients to reduce niche overlap. Greater spatial overlap (SO) between species due to water column mixing could thus promote competitive exclusion, reducing community taxonomic diversity. However, greater SO could also promote coexistence of functionally different taxa. Using data from a whole-lake experiment, we investigated the effects of SO and other relevant environmental factors on phytoplankton diversity across the water columns of lake basins with different thermocline manipulations. We estimated SO using an in situ fluorometer, and overall community diversity microscopically. Using structured equation models, we estimated directional relationships between phytoplankton diversity, SO, the lake physical structure and the zooplankton community. No significant effect of SO on phytoplankton taxonomic diversity was observed, but higher SO was associated with greater functional diversity. Change in lake physical structure and in the zooplankton community also affected diversity, with a negative response to increased top-down interactions. Overall, despite the fact that the alteration of water column stratification structure and top-down interactions were stronger drivers of phytoplankton diversity in our system, some effect of spatial overlap on the outcome of inferred competitive interactions were observable.


2021 ◽  
Author(s):  
Erez Harpaz ◽  
Cecilie Ersdal ◽  
Michael Tranulis ◽  
Arild Espenes ◽  
Øyvind Salvesen ◽  
...  

Abstract Background: Chronic wasting disease (CWD) is a prion disease of cervids. In 2016, CWD was discovered for the first time in reindeer. The affected population was situated in Nordfjella mountain region in Norway. In an attempt to eradicate the disease, all reindeer in the region were culled during winter 2017-18. Because many sheep have their summer pasture in Nordfjella, concern exists about the potential cross-species transmission of CWD to sheep. In this study, global positioning system (GPS) data from sheep and reindeer from the relevant time frame were analyzed to determine spatial overlap. Samples of gut-associated lymphoid tissue (GALT) from 503 lambs and sheep having grazed in the region were analyzed for the presence of prions. The rectoanal mucosa-associated lymphoid tissue (RAMALT) from all animals and ileal Peyer's patch (IPP) from 37 of them, were examined by histology, immunohistochemistry (IHC), and enzyme-linked immunosorbent assay (ELISA). Results: GPS data showed a direct overlap in area use between an infected reindeer and some of the sampled sheep. Generally, the sampled sheep herding areas were used intensively by reindeer before culling. No prions were detected in the GALT of sheep. The mean lymphoid follicle number per sample was 22.6 for RAMALT and 37.5 for IPP. Conclusion: Despite evidence of close reindeer to sheep interaction and spatial overlap in Nordfjella, prions were not detected in the GALT of sheep.. We document that the easily accessible RAMALT tissue at the mucocutaneous border is well suitable for slaughterhouse screening of prions in sheep.


Author(s):  
Kendall L. Calhoun ◽  
Melissa Chapman ◽  
Carmen Tubbesing ◽  
Alex McInturff ◽  
Kaitlyn M. Gaynor ◽  
...  

Marine Policy ◽  
2021 ◽  
Vol 130 ◽  
pp. 104551
Author(s):  
Oihana Solaun ◽  
Yolanda Sagarminaga ◽  
Iratxe Menchaca ◽  
Ibon Galparsoro

2021 ◽  
Vol 9 (8) ◽  
pp. 1578
Author(s):  
Rubén Morón-Asensio ◽  
David Schuler ◽  
Anneliese Wiedlroither ◽  
Martin Offterdinger ◽  
Rainer Kurmayer

The cyanoHAB forming cyanobacteria Microcystis and Planktothrix frequently produce high intracellular amounts of microcystins (MCs) or anabaenopeptins (APs). In this study, chemically modified MCs and APs have been localized on a subcellular level in Microcystis and Planktothrix applying copper-catalyzed alkyne-azide cycloaddition (CuACC). For this purpose, three different non-natural amino acids carrying alkyne or azide moieties were fed to individual P. agardhii strains No371/1 and CYA126/8 as well as to M. aeruginosa strain Hofbauer showing promiscuous incorporation of various amino acid substrates during non-ribosomal peptide synthesis (NRPS). Moreover, CYA126/8 peptide knock-out mutants and non-toxic strain Synechocystis PCC6803 were processed under identical conditions. Simultaneous labeling of modified peptides with ALEXA405 and ALEXA488 and lipid staining with BODIPY 505/515 were performed to investigate the intracellular location of the modified peptides. Pearson correlation coefficients (PCC) obtained from confocal images were calculated between the different fluorophores and the natural autofluorescence (AF), and between labeled modified peptides and dyed lipids to investigate the spatial overlap between peptides and the photosynthetic complex, and between peptides and lipids. Overall, labeling of modified MCs (M. aeruginosa) and APs (P. agardhii) using both fluorophores revealed increased intensity in MC/AP producing strains. For Synechocystis lacking NRPS, no labeling using either ALEXA405 or ALEXA488 was observed. Lipid staining in M. aeruginosa and Synechocystis was intense while in Planktothrix it was more variable. When compared with AF, both modified peptides and lipids showed a heterologous distribution. In comparison, the correlation between stained lipids and labeled peptides was not increased suggesting a reduced spatial overlap.


PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0253914
Author(s):  
R. Anne Richards ◽  
Margaret Hunter

The northern shrimp (Pandalus borealis Krøyer) population in the Gulf of Maine collapsed during an extreme heatwave that occurred across the Northwest Atlantic Ocean in 2012. Northern shrimp is a boreal species, and reaches its southern limit in the Gulf of Maine. Here we investigate proximate causes for the population collapse using data from fishery-independent surveys, environmental monitoring, and the commercial fishery. We first examined spatial data to confirm that the decline in population estimates was not due to a major displacement of the population, and then tested hypotheses related to fishing mortality and shifts in predation pressure. Fishing mortality may have contributed but could not explain the magnitude of the decline or the disappearance of pre-exploitable size individuals. Stomach contents analysis and biomass trends revealed no new fish predators of shrimp. However, longfin squid (Doryteuthis pealeii Lesueur) was unique among all species in showing time-series biomass peaks during spring, summer and fall of 2012, and spatial overlap with northern shrimp was unusually high in 2012. Longfin squid is a voracious and opportunistic predator that consumes crustaceans as well as fish. We hypothesize that the warmer temperatures of 2012 not only led to expansion of longfin squid distribution in Gulf of Maine, but had differential effects on migration phenology that further increased spatial overlap with northern shrimp. The weight of our evidence suggests that longfin squid predation was likely a significant factor in the collapse of northern shrimp in the Gulf of Maine.


2021 ◽  
Vol 38 ◽  
pp. 1-10
Author(s):  
Carlos A. Contreras-Díaz ◽  
Leroy Soria-Díaz ◽  
Yuriana Gómez-Ortiz ◽  
Rogelio Carrera-Treviño ◽  
Claudia C. Astudillo-Sánchez ◽  
...  

Jaguars, Panthera onca (Linnaeus, 1758), and pumas, Puma concolor (Linnaeus, 1771) are the largest felids in the neotropics. Both can overlap in niche axes (time, space and prey), and are therefore potentially competing species. Segregation mechanisms presented by a low overlap in one of these axes of niche can facilitate the coexistence. Our aim was to analyze jaguar and puma temporal and spatial overlap for understanding their segregation mechanisms. Between 2015 and 2017, twenty-six camera trap stations were located in five habitat types of El Cielo Biosphere Reserve (ECBR) in northeastern Mexico. Temporal activity was analyzed using circular statistics and time overlap analysis. Spatial overlap was calculated with the Pianka index and a selectivity habitat analysis. Our results showed that jaguars and pumas were nocturnal and that the temporal overlap was high (∆4 = 0.77). We found an intermediate spatial overlap (Pianka index = 0.61). Jaguars were more selective and preferred the deciduous forest. In comparison, pumas preferred oak-pine forest, but also used oak and deciduous forest. Our results indicate that spatial segregation best explains the coexistence of jaguars and pumas in our study area, probably due to both habitat diversity in the reserve and the generalist habits of the puma.


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