Biogeography of salt marsh plant zonation on the Pacific coast of South America

Abstract

Aim: The aim of this study was to investigate the biogeography of plant zonation in salt marshes on the Pacific coast of South America; to examine whether salt marsh plant zonation varies with latitude; and to explore the relative importance of climatic, tidal, edaphic and disturbance factors in explaining large-scale variation in salt marsh plant community structure.Location: A 2,000-km latitudinal gradient on the Pacific coast in Chile, with a climate shift from hyper-arid at low to hyper-humid at high latitudes.Methods: Plant zonation was quantified in field surveys of ten marshes. Climate, tidal regimes, edaphic factors and disturbances (tsunami and rainfall floods) were determined. We used multivariate analyses to explore their relative importance in explaining large-scale variation in salt marsh plant community structure.Results: Across latitude, marshes were dominated by distinct plant communities in different climate regions, especially at the extreme dry and wet latitudes. Intertidal plant species zonation was present in hyper-arid and semi-arid climates, but not in arid, humid and hyper-humid climates. Latitudinal variation in low-marsh plant communities (regularly flooded at high tide) was largely a function of precipitation, while at high marshes (never flooded at high tide) latitudinal variation was explained with precipitation, temperature, tidal cycles, soil salinity and disturbances. These patterns appear to be mechanistically explained by extrapolating experimentally generated community assembly models and have implications for predicting responses to climate change.

Saltmarsh conservation through inventory, biogeographic analysis and predictions of change: Case of Tasmania, south‐eastern Australia

“…Climatic factors best explained the distribution of Tasmanian saltmarsh plant community types, obligate species and salt pans, a finding consistent with much of the theoretical literature (Adam, ; Chapman, ; Malamud‐Roam et al, ; Osland et al, ; Pennings & Bertness, ) and case studies demonstrating the predominance of climatic factors in saltmarsh biogeography at both regional and continental scales (e.g. Fariña et al, ; Isacch et al, ; Osland et al, , ; Saintilan, ). As well as restricting the distribution of succulent saltmarsh, high rainfall appears effective in the exclusion of saltmarsh from the major rivers and numerous smaller creeks along the west coast.…”

“…At a continental scale, Saintilan () related latitude and mean minimum temperature to patterns in the distribution of Australian saltmarsh plants. Fariña, He, Silliman, and Bertness () defined bioregional differences in Chilean saltmarshes along a 2,000 km latitudinal climatic gradient of increasing annual precipitation (~45–1,554 mm) and decreasing mean annual temperature (~17–9.5°C). In North America, a latitudinal climatic gradient was used to explain differences in saltmarsh vegetation and salt pan formation (Bertness & Pennings, ).…”

“…tidal range/regime, landscape setting/physiography) and land use (e.g. urban and agricultural development, grazing, eutrophication) (Adam, ; Fariña et al, ; Isacch et al, ; Osland, Enwright, Day, & Doyle, ; Osland, Enwright, & Stagg, ; Saintilan, ). There is need to understand the combination of these macroscale environmental factors that predict patterns and processes in saltmarsh vegetation in individual regions across the world (Adam, ; Bertness & Pennings, ; Kunza & Pennings, ; Malamud‐Roam, Malamud‐Roam, Watson, Collins, & Ingram, ; Osland et al, ; Pennings & Bertness, ).…”

Partitioning the effects of regional, spatial, and local variables on beta diversity of salt marsh arthropods in Chile

“…Coastal salt marshes are excellent model systems for studying large-scale variation in species composition, especially for plants because of the simplicity of their community (Bertness & Ewanchuk, 2002;Fariña, He, Silliman, & Bertness, 2017;Pennings, Siska, & Bertness, 2001). Salt marshes along the Chilean coast exhibit strong climatic gradients.…”

Inventory of Aquatic Macrophyte Species in Coastal Rivers of the São Paulo State, Brazil

“…At global and very wide scales, the processes that drive the macrophyte distribution in low-and high-latitude estuaries are mainly related to the differences of precipitation, temperature and solar radiation (Pennings & Bertness 1999). At these scales, the studies are based on the comparison of single areas (Fariña et al 2017). At more regional and local scales, it is possible to focus on continuous areas and, although the importance of climate gradient is relevant (Fariña et al 2017), the edaphic and geomorphological differences of the aquatic ecosystems may be the principal drivers to the north-south distribution of macrophyte species (Isacch et al 2006, Fariña et al 2017.…”