Species distribution, ecology, abundance, body size and phylogeny originate interrelated rarity patterns at regional scale

Abstract

The most pervasive macroecological patterns concern (1) the frequency distribution of range size, (2) the relationship between range size and species abundance and (3) the effect of body size on range size. We investigated these patterns at a regional scale using the tenebrionid beetles of Latium (Central Italy). For this, we calculated geographical range size (no. of 10-km square cells), ecological tolerance (no. of phytoclimatic units) and abundance (no. of sampled individuals) using a large database containing 3561 georeferenced records for 84 native species. For each species, we also calculated body mass and its ‘phylogenetic diversity’ on the basis of cladistic relationships. Frequency distribution of range size followed a log-normal distribution as found in many other animal groups. However, a log-normal distribution accommodated well the frequency distribution of ecological tolerance, a so far unexplored issue. Range size was correlated with abundance and ecological tolerance, thus supporting the hypothesis that a positive correlation between distribution and abundance is a reflection of interspecific differences in ecological specialization. Larger species tended to have larger ranges and broader ecological tolerance. However, contrary to what known in most vertebrates, not only small-sized, but also many medium-to-large-sized species exhibited great variability in their range size, probably because tenebrionids are not so strictly influenced by body size constraints (e.g. home ranges) as vertebrates. Moreover, in contrast to other animals, tenebrionid body size does not influence species abundances, probably because these detritivorous animals are not strongly regulated by competition. Finally, contrary to the assumption that rare species should be mainly found among lineages that split from basal nodes, rarity of a tenebrionid species was not influenced by the phylogenetic position of its tribe. However, lineages that split from more basal nodes had lower variability in terms of species geographical distribution, ecological tolerance and abundance, which suggests that lineages that split from more basal nodes are not only morphologically conservative but also tend to have an ecological ‘inertia’

Deconstructing occupancy frequency distributions in stream insects: effects of body size and niche characteristics in different geographical regions

“…It is possible, for example, that large insect species are more widely distributed (Hoffsten, 2004;Fattorini et al, 2013) because they are stronger active fliers than small species (Hoffsten, 2004;Heino, 2013), and they should thus show more uniform OFDs than small species. Small species should be a more species-rich group than that of larger species (Hutchinson & MacArthur, 1959), and the probability of finding more rare species should thus increase with decreasing body size and lead to pronounced satellite mode in OFDs.…”

Macroecological relationships reveal conservation hotspots and extinction‐prone species in Australia's freshwater fishes

“…Consequently, range size and body size relationships are some of the most consistent macroecological patterns across a variety of taxa (Brown, ; Lawton, , ; Gaston & Blackburn, ). Range size increases with body size in birds (Brown & Maurer, ), mammals (Brown & Maurer, ), beetles (Fattorini et al ., ), marine fish (Strona et al ., ) and freshwater fish (Pyron, ; Rosenfield, ; Bertuzzo et al ., ) with few exceptions (Gaston & Blackburn, ; Blanchet et al ., ). Larger species have greater ranges, primarily due to increased energy demands (Brown & Maurer, ) and dispersal capacity (Jenkins et al ., ).…”

Moving beyond the guild concept: developing a practical functional trait framework for terrestrial beetles

“…Such studies have often attempted to link life‐history traits to species decline (e.g. Davies et al ., ; Fattorini et al ., ). Most have found that interactions among multiple traits were most useful for predicting which species are more at risk of extinction (Davies et al ., ; Henle et al ., ; Driscoll & Weir, ; Fattorini et al ., ).…”

“…Davies et al ., ; Fattorini et al ., ). Most have found that interactions among multiple traits were most useful for predicting which species are more at risk of extinction (Davies et al ., ; Henle et al ., ; Driscoll & Weir, ; Fattorini et al ., ). For example, species abundance combined with habitat selection (specialists/generalists) explains some species' sensitivity to decline (Davies et al ., ).…”