Niche conservatism and the potential for the crayfishProcambarus clarkiito invadeSouthAmerica

Abstract

Summary Invasive species are one of the most severe threats to biodiversity, and an ability to predict the extent of potential invasions can help conservation strategies. Species distribution models (SDMs) have been widely used to project the potential range of invasive species. These models assume that species retain their niche properties during invasion (niche conservatism), although this assumption is seldom verified. We gathered occurrence records for the crayfish Procambarus clarkii from the U.S.A. and Mexico (native + invasive ranges) and from the Iberian Peninsula (invasive) to test for niche conservatism across continents using niche overlap metrics (Schoener's D). To test for differences in the climate space occupied by the species on the different continents, we performed two principal component analyses (PCAs) on the environmental data extracted from occurrence records: first, separately for each occurrence data set (i.e. each continent) and secondly, using the pooled data. Subsequently, we projected the model to South America, where this species has the potential to become invasive. Schoener's D showed high overlap (0.68) between the two regions (the Americas and Iberia), and there was no difference between the regions in both PCAs. The crayfish has conserved its niche across continents, and therefore, our model projection to South America may accurately demonstrate where invasion is most likely to occur. Large parts of South America are apparently suitable, mainly Argentina, Chile, Paraguay, Uruguay and southern Brazil. This result is of great concern since this invasive species can spread quickly in suitable areas. Stronger laws and regulations should be made to protect native biodiversity and agricultural land. Our approach could be replicated for the study of invasions by other species where extensive data on the potentially invaded areas are available.

Diversity and conservation status of Aegla spp. (Anomura, Aeglidae): an update

“…Nauplius, 25: 2017011 derive from different sources: removal of riparian forest, causing siltation (Magris et al, 2010); habitat modification, fragmentation and destruction (Cumberlidge et al, 2009;Reid et al, 2013); freshwater contamination with agricultural pesticide (Magris et al, 2010;Negro et al, 2015;Stehle and Schulz, 2016); construction of dams that alter the flow and sometimes the temperature of the water as well (Olsson, 2015); urban and agricultural activities which modify the physical and chemical characteristics of water bodies and freshwater biota composition (Milesi et al, 2008;Hepp and Santos, 2009;Hepp et al, 2010;Magris et al, 2010); invasive species (Palaoro et al, 2013;Loureiro et al, 2015), among others. Threats to the family Aeglidae, specifically, have been identified and listed, as the use of biocides in wine and fruit farms in Chile, silviculture of exotic species, largescale cultivation of potatoes and apples with extensive use of pesticides, and hog raising activities along southern rivers in Brazil (Bond-Buckup et al, 2008), beyond severe deforestation in Paraguay (Satterlee et al, 2012).…”

Niche Conservatism and the Future Potential Range of Epipactis helleborine (Orchidaceae)

“…While some studies have indicated the tendency to retain the niche of the species in its non-native range [41], others have proved a change in the fundamental niche in the invaded area [36]. The situation of Broad-leaved Helleborine is more complex.…”

How to deal with a bad neighbor? Strategies of sympatric freshwater decapods (Crustacea) for coexistence

“…We performed more measurements at night (in relation to daytime) due to both groups exhibiting predominantly nocturnal activity. Therefore, high rates of displacements were expected during this time (Sokolowicz et al, 2007;Palaoro et al, 2013a). We chose to monitor the individuals for 7 days because the radio signal from several tags started to fade after this time, and we therefore deemed radio-tracking information gathered after this threshold unreliable for data analysis.…”

“…They are ecologically similar in many aspects, such as having a generalist diet, preferring to inhabit loworder streams and showing nocturnal activity (Santos et al, 2008;Zimmermann et al, 2009;Collins et al, 2011;Dalosto & Santos, 2011;Palaoro et al, 2013a). The most commonly encountered groups are anomurans of the genus Aegla, and crayfish of the genus Parastacus (Dalosto & Santos, 2011).…”