Effects of large‐scale disturbance on metacommunity structure of terrestrial gastropods: temporal trends in nestedness

Abstract

Distributions of species often exhibit nested structure, such that assemblages at species-poor sites are proper subsets of taxa at more species-rich sites. Traditionally, this has been viewed as a large-scale biogeographic pattern and treated implicitly as static from a temporal perspective. Nonetheless, recent work suggests that nestedness may arise at multiple spatio-temporal scales. A 13-year data set encompassing the effects of two largescale natural disturbances (hurricanes Hugo and Georges) on terrestrial gastropod assemblages was used to test the hypothesis that changes in species composition resulting from disturbance alter the degree of nestedness exhibited over time at two spatial scales. Gastropod assemblages were least nested immediately following disturbance, and nestedness increased thereafter. Although land-use history influenced the degree of nestedness, trajectories of nestedness following disturbance were similar irrespective of disturbance history or hurricane identity. The effects of hurricanes with respect to nestedness of terrestrial gastropods may be general and predictable, even though species respond to hurricanes in disparate fashions. By damaging some localities within the forest more severely than others, a hurricane dismantles extant patterns of species composition and severs connections among sites, as inhospitable microclimatic conditions limit dispersal of gastropods. As time passes and the forest canopy regenerates, conditions ameliorate, and movement among sites becomes more frequent. Thus, a conclusion based on a single time period may not characterize the study system in general. Consequently, explanations for nested structure that incorporate variability in ecological as well as evolutionary time will improve the applicability and comparability of nested subsets analysis across study systems.

Gastropod communities in alpine grasslands are characterized by high beta diversity

“…As our analytical tool is relatively novel, we were not able to assess whether this pattern is characteristic for gastropod communities in general, or only for gastropod communities in alpine grasslands. Other studies showed that differences in habitat quality explain nestedness in litter-dwelling land snail communities in boreal riparian forest (Hylander et al 2005) and that large-scale disturbances by hurricans altered the degree of nestedness in land snail communities in tropical wet forest in Puerto Rico (Bloch et al 2007). …”

Exploring the Ecology of Deep-Sea Hydrothermal Vents in a Metacommunity Framework

“…In both marine and terrestrial systems, it is becoming clear that understanding resilience to disturbance requires investigation of dispersal in addition to local influences, as demonstrated by field studies in estuaries (Thrush et al, 2008), forests (Bloch et al, 2007), and streams (Campbell et al, 2015).…”

Responses to canopy loss and debris deposition in a tropical forest ecosystem: Synthesis from an experimental manipulation simulating effects of hurricane disturbance

“…3). From measurements after Hurricanes Hugo and Georges, Bloch et al (2007) determined that the patchiness of canopy structure produced by hurricanes is particularly important for predicting sites occupied by snails. In general, it was surprising to find that the canopy trimming (including Trim + debris plots) had such a large effect on decreasing populations of litter arthropods (Richardson et al, 2010), gastropods , and coqui frogs (Klawinski et al, 2014), whereas debris addition had (in most cases) little to no effect on these populations.…”

“…Predator-prey relationships need further examination following hurricane passages to better determine drivers of changes and cascading trophic effects (e.g., Richardson et al, 2010;Schowalter et al, 2014). Movement dynamics appear critical to better understand both the importance of patch size effects on animal populations (e.g., Bloch et al, 2007) and the extent to which predators (e.g., coqui frogs, some arthropods) track prey after hurricanes. Diet shifts in predators may also be expected with the hypothesized changes in available habitat and prey that result from hurricanes (Waide, 1991).…”

“…In addition to determining the mechanisms driving forest responses to hurricane disturbances, a second phase of the CTE has been planned to experimentally test the effects of repeated hurricanes on abiotic, biotic, and structural characteristics of the LEF. Forest responses from multiple hurricanes at a site over a relatively short period (e.g., weeks to <10 years) are influenced by preceding hurricanes (Burslem et al, 2000;Ostertag et al, 2003Ostertag et al, , 2005Bloch et al, 2007), and therefore forest attributes may respond differently given the hurricane history. For example, Cecropia schreberiana, which is the co-dominant tree after hurricanes in the LEF (Brokaw, 1998;Shiels et al, 2010), first flowers and fruits at 6 years of age (Silander, 1979;Brokaw, 1998); thus, reduced intervals between major hurricanes (e.g., <6 years) will probably have significant effects on post-hurricane plant community structure and ecosystem processes.…”