scholarly journals Species richness and interacting factors control invasibility of a marine community

2015 ◽  
Vol 282 (1812) ◽  
pp. 20150439 ◽  
Author(s):  
M. L. Marraffini ◽  
J. B. Geller

Anthropogenic vectors have moved marine species around the world leading to increased invasions and expanded species' ranges. The biotic resistance hypothesis of Elton (in The ecology of invasions by animals and plants , 1958) predicts that more diverse communities should have greater resistance to invasions, but experiments have been equivocal. We hypothesized that species richness interacts with other factors to determine experimental outcomes. We manipulated species richness, species composition (native and introduced) and availability of bare space in invertebrate assemblages in a marina in Monterey, CA. Increased species richness significantly interacted with both initial cover of native species and of all organisms to collectively decrease recruitment. Although native species decreased recruitment, introduced species had a similar effect, and we concluded that biotic resistance is conferred by total species richness. We suggest that contradictory conclusions in previous studies about the role of diversity in regulating invasions reflect uncontrolled variables in those experiments that modified the effect of species richness. Our results suggest that patches of low diversity and abundance may facilitate invasions, and that such patches, once colonized by non-indigenous species, can resist both native and non-indigenous species recruitment.

Author(s):  
Jean Béguinot

The genus Conus forms a conspicuous and rather homogeneous group within marine Gastropods. This makes it all the more interesting to focus on the sub-communities formed by Conus species and to analyze the potential specificities in the internal organization of species in these communities, in particular species richness, species abundance distribution and the effect of geographical distance between communities on differences in their respective species composition. Accordingly, two Conus communities along the coast in Mannar Gulf (India), separated by 80 km, are considered. Reliable analysis requires, first, to treat exhaustive data from complete samplings or, else – as here – to implement an appropriate extrapolation procedure to complete numerically the partial samplings. After numerical completion, substantial differences were highlighted between the two communities, not only in terms of true (total) species richness but, even more, as regards the profile and the average unevenness of the distributions of species abundance. Also, significant dissimilarity in species composition was found between the two communities, that may be tentatively attributed to either deterministic distance decay in similarity of species composition or, alternatively, to the persistence in the stochastic process of species recruitment from the regional stock of Conus planktonic larvae. This preliminary study yet requests to be complemented by other similar case studies, before drawing any safer interpretative conclusions.


Author(s):  
Frederic Mineur ◽  
Mark P. Johnson ◽  
Christine A. Maggs

It has traditionally been considered that areas with high natural species richness are likely to be more resistant to non-indigenous species than those with lower numbers of species. However, this theory has been the subject of a debate over the last decade, since some studies have shown the opposite trend. In the present study, a macroalgal survey was carried out at 24 localities in Northern Ireland and southern England, using a quadrat approach in the lower littoral. The two opposing hypotheses were tested (negative versus positive relationship between native and non-indigenous species richness) in this marine environment. The effect of the presence of ‘impacts’, potential sources of disturbance and species introduction (e.g. marina, harbour or aquaculture), was also tested. A positive relationship was found between the number of non-indigenous species and the native species richness at the three different scales tested (quadrats, sites and localities). At no scale did a richer native assemblage appear to restrict the establishment of introduced species. The analyses revealed greater species richness and different community composition, as well as more non-indigenous species, in southern England relative to Northern Ireland. The presence of the considered impacts had an effect on the community composition and species richness in southern England but not in Northern Ireland. Such impacts had no effect on the non-indigenous species richness in either area.


2008 ◽  
Vol 20 (3) ◽  
pp. 271-280 ◽  
Author(s):  
David K.A. Barnes ◽  
Katrin Linse ◽  
Peter Enderlein ◽  
Dan Smale ◽  
Keiron P.P. Fraser ◽  
...  

AbstractStudies of the recovery of the fauna following the 1967–70 eruptions at Deception Island, South Shetland Islands, have made it one of the best-studied marine sites of the Southern Ocean for biodiversity. Using SCUBA we surveyed the mega- and macro-epifauna of its subtidal zones in the entrance (Neptune's Bellows), immediately inside the caldera (Whaler's Bay) and well within the caldera (Fumarole Bay). Richness declined from 10 phyla, 13 classes and 35 species at Neptune's Bellows to three phyla, four classes and five species in Whaler's Bay and just two phyla, classes and species at Fumarole Bay. Amongst the 35 species we found at Neptune's Bellows, 14 were previously unrecorded from Deception Island. Despite many ship visits and amongst the warmest sea temperatures in the Southern Ocean, the Non Indigenous Species (NIS) algae were not found in our survey. Deception Island has been recolonized considerably since the recent eruptions, but many taxa are still very poorly represented and the colonizers present are mainly those with planktotrophic larvae. Examination of the literature revealed that to date 163 named marine species have been found within the caldera as well as at least 50 more morphospecies, which are yet to be identified. Species accumulation has consistently increased across eight recent samples reported and the number of species reported there is likely to reach 300 when taxa such as the nematodes are identified to species level. This represents a first meaningful total species estimate for an Antarctic marine area and, as the site is comparatively impoverished, indicates how rich the surrounding Antarctic shelf must be.


Author(s):  
Jean Béguinot

The role of coral reef architecture on species richness and the internal structuration of the associated fish communities has already been addressed several times. The reported results, however, usually remain controversial, possibly because they are based upon incomplete field data issued from partial inventories. Indeed, incomplete samplings are almost unavoidable in practice with such species-rich communities having very uneven distribution of abundances. In this context, the numerical extrapolation of incompletely sampled communities may serve as a reliable surrogate. Accordingly, numerical extrapolations were implemented, here, to compare two fish-communities respectively associated to coral reefs that sharply differ from each-other by their topographic architectures. Both a higher total species richness and a sharper unevenness of species abundances were found to characterize the fish community associated to the more tormented reef habitat exhibiting the more complex architecture. Yet, paradoxically, the true intensity of the underlying process of hierarchical structuring of abundances proves being insensitive to the architecture of coral habitats. This apparent opposition between the unevenness pattern and the underlying structuring process results, in fact, from the additional negative dependence of abundance unevenness upon species richness.


Author(s):  
Heather Marks

Non-native species invasions in national parks directly interfere with the major management goal of protecting native biota. The status of species richness and non-native invasions was assessed in five riparian vegetation types in Grand Teton National Park, Wyoming, with nested-scale number and frequency vegetation data using a Modified­Whittaker sampling design. In the 20 (1OOO-m2 plots sampled, non-native species represented 11.9% (35) of the total 294 species recorded. Non-native species were found in small populations either widely dispersed across the five vegetation types or appearing to have some level of habitat specificity. Total species richness across the five vegetation types varied from 42 species in the sage community to 96 species in the conifer-broadleaf community. Overall, mean species richness across the five communities was 81.9 species/0.1 ha. A suite of environmental variables such as nutrient availability, flood regime, herbivory as well as successional trends may explain the variability in species richness across communities. Patterns of total species richness across multiple scales were fairly consistent. Patterns of non-native species invasion, however, appeared to be both scale and vegetation type dependent. The highest proportion of non-native species for four of the five vegetation types was recorded at the smaller sampling scales. The alder community was the most invaded at all scales measured and had the most distinct assemblage of non-native species. Some studies suggest that community invasibility may be related to species richness. At the 1-m2 and 1000- m2 scales, total species richness and number of non-native species were significantly and positively correlated. When the alder sites were removed from analysis at the 1000- m2 scale, the positive linear relationship increased, and the total variance explained by the linear models was enhanced by 38%. At all scales sampled, the alder sites were highly and disproportionately invaded, often more than twice the level of other communities. The mechanism of nitrogen fixation may be promoting non-native invasions in the alder community. At the vegetation type scale (combined species lists from four 1OOO-m2 plots in each community), those communities with the most unique non-native assemblages were the most invaded. A significant negative linear relationship between non­native species overlap and percentage of non-native species was observed in the alder sites at each scale sampled. This pattern suggests some relationship between properties of an invading species and properties of the community that it invades. Because the results of this study suggest species rich riparian landscapes are vulnerable to non-native invasions, recommendations are offered to assist managers in responding efficiently and effectively to this conservation priority.


2008 ◽  
Vol 38 (7) ◽  
pp. 1807-1816 ◽  
Author(s):  
Björn Nordén ◽  
Frank Götmark ◽  
Martin Ryberg ◽  
Heidi Paltto ◽  
Johan Allmér

Partial cutting is increasingly applied in European temperate oak-dominated forests for biofuel harvesting, and to counteract succession in protected stands. Effects on biodiversity of these measures need to be carefully evaluated, and species-rich but neglected taxa such as fungi should be considered. We studied the effects of partial cutting on fungal fruiting bodies on woody debris. In 21 closed canopy forests rich in large oaks in Sweden, on average 25%–30% of the basal area was cut. Fruiting bodies were counted and some were collected in treated and control plots before and after treatment. We found 334 basidiomycete and 47 ascomycete species. Species richness of basidiomycetes declined significantly more in treated plots (on average 26%) than in control plots (on average 13%) between seasons. Species richness of ascomycetes increased by 17% in control plots and decreased by 2% in treated plots. Total species richness was significantly reduced on fine woody debris (1–10 cm in diameter), but not on coarse woody debris (>10 cm). Overall species composition did not change significantly as a result of partial cutting, but red-listed species tended to decrease more in treated plots. We suggest that approximately 30% of the stands should not be thinned, and dead stems and fallen branches should not be removed, to favor saproxylic fungi and their associated fauna.


2007 ◽  
Vol 50 (6) ◽  
pp. 1033-1042 ◽  
Author(s):  
Yzel Rondon Súarez ◽  
Sabrina Bigatão Valério ◽  
Karina Keyla Tondado ◽  
Alexandro Cezar Florentino ◽  
Thiago Rota Alves Felipe ◽  
...  

The influence of spatial, temporal and environmental factors on fish species diversity in headwater streams in Paraguay and Paraná basins, Brazil was examined. A total of 4,605 individuals were sampled, distributed in 60 species. The sampled streams in Paraná basin presented a larger total species richness (42) than Paraguay streams (40). However the estimated richness was larger in Paraguay basin (53) than Paraná streams (50). The streams of Paraná basin had a greater mean species richness and evenness, while more individuals per sample were found in the Paraguay basin. Difference between the sub-basins were found in the Paraguay basin, while for the basin of Paraná, richness and evenness vary significantly between the sub-basins, but the number of individuals varied seasonally. The most important environmental factors to species diversity and abundance were altitude, water temperature, stream width and stream depth for both the basins.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tanya A. Petruff ◽  
Joseph R. McMillan ◽  
John J. Shepard ◽  
Theodore G. Andreadis ◽  
Philip M. Armstrong

Abstract Historical declines in multiple insect taxa have been documented across the globe in relation to landscape-level changes in land use and climate. However, declines have either not been universally observed in all regions or examined for all species. Because mosquitoes are insects of public health importance, we analyzed a longitudinal mosquito surveillance data set from Connecticut (CT), United States (U.S.) from 2001 to 2019 to identify changes in mosquito community composition over time. We first analyzed annual site-level collections and metrics of mosquito community composition with generalized linear/additive mixed effects models; we also examined annual species-level collections using the same tools. We then examined correlations between statewide collections and weather variables as well as site-level collections and land cover classifications. We found evidence that the average trap night collection of mosquitoes has increased by ~ 60% and statewide species richness has increased by ~ 10% since 2001. Total species richness was highest in the southern portion of CT, likely due to the northward range expansion of multiple species within the Aedes, Anopheles, Culex, and Psorophora genera. How the expansion of mosquito populations in the northeast U.S. will alter mosquito-borne pathogen transmission in the region will require further investigation.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Simon J. McKirdy ◽  
Simon O’Connor ◽  
Melissa L. Thomas ◽  
Kristin L. Horton ◽  
Angus Williams ◽  
...  

AbstractLarge sea-going passenger vessels can pose a high biosecurity risk. The risk posed by marine species is well documented, but rarely the risk posed by terrestrial arthropods. We conducted the longest running, most extensive monitoring program of terrestrial arthropods undertaken on board a passenger vessel. Surveillance was conducted over a 19-month period on a large passenger (cruise) vessel that originated in the Baltic Sea (Estonia). The vessel was used as an accommodation facility to house workers at Barrow Island (Australia) for 15 months, during which 73,061 terrestrial arthropods (222 species - four non-indigenous (NIS) to Australia) were collected and identified on board. Detection of Tribolium destructor Uytt., a high-risk NIS to Australia, triggered an eradication effort on the vessel. This effort totalled more than 13,700 human hours and included strict biosecurity protocols to ensure that this and other non-indigenous species (NIS) were not spread from the vessel to Barrow Island or mainland Australia. Our data demonstrate that despite the difficulties of biosecurity on large vessels, stringent protocols can stop NIS spreading from vessels, even where vessel-wide eradication is not possible. We highlight the difficulties associated with detecting and eradicating NIS on large vessels and provide the first detailed list of species that inhabit a vessel of this kind.


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