Biodiversity of benthic assemblages on the Arctic continental shelf: historical data from Canada

Abstract

This study describes patterns of abundance, diversity, and assemblages of benthic macrofauna within the Canadian Arctic Archipelago. A review of data reports and the published literature yielded 219 stations and 947 taxa from 7 sources in various regions of the Canadian Arctic Archipelago (i.e. Beaufort Sea and Mackenzie Shelf, Victoria Island, Hudson and James Bays, Frobisher Bay, Ungava Bay, and Southern Davis Strait). In general, we observed that eastern regions of the Canadian Arctic Archipelago showed greater values of species richness (or α diversity) than the western and central regions, whereas no specific patterns were observed for Shannon-Wiener's diversity (H') and Pielou's evenness (J') indices. The Beaufort Sea and Mackenzie Shelf region exhibited high values of taxonomic distinctness (Δ + ), whereas Hudson Bay showed low values. However, the Hudson Bay region showed high values of turnover (β W ) diversity. A non-metric multi-dimensional scaling plot of similarity (Bray-Curtis index) and analysis of similarity revealed that species composition differed among regions, even those located in close proximity to one another. These investigations were conducted at different levels of taxonomic resolution (Species, Order, Class and Phyla) and the results demonstrated that most patterns were maintained up to the Order and Class level. A relatively small number of taxa, mainly annelids, were responsible for most of the dissimilarity among regions. Bottom salinity and temperature were the most important environmental variables (among depth of site, bottom temperature, salinity, physical and chemical sediment characteristics) for determining these assemblage patterns. Multiple regression analyses also demonstrated that variance in species richness and diversity (H') was best explained by variance in salinity (55 and 43% respectively). The analysis of a time series from Frobisher Bay revealed that the temporal (mo/yrscale) variability of assemblages was of the same order as the spatial (km-scale) variability among sites.KEY WORDS: Benthic assemblage · Meta-analysis · Historical data · Arctic macrobenthos · Multivariate analysis · α, γ, and turnover (β) diversity · Spatial and temporal variabilityResale or republication not permitted without written consent of the publisher

Regional Variability of Megabenthic Community Structure across the Canadian Arctic

“…Except in taxon richness, the geographical regions did not differ significantly in their mean benthic community characteristics, revealing a high similarity in community structure among regions. Contrary to our results, Cusson et al (2007) reported on the basis of historical macrobenthic data from the 1950s to 1970s that the Beaufort Sea region had moderate species richness and low Hʹ diversity compared to eastern regions of the Canadian Arctic. Our study did not include nearshore stations, which are often under severe seasonal disturbances such as variable salinity and ice scouring, which were suggested to drive some of the observed difference in macrofaunal diversity patterns (Cusson et al, 2007).…”

“…Contrary to our results, Cusson et al (2007) reported on the basis of historical macrobenthic data from the 1950s to 1970s that the Beaufort Sea region had moderate species richness and low Hʹ diversity compared to eastern regions of the Canadian Arctic. Our study did not include nearshore stations, which are often under severe seasonal disturbances such as variable salinity and ice scouring, which were suggested to drive some of the observed difference in macrofaunal diversity patterns (Cusson et al, 2007). The distinctiveness of the Beaufort Sea region was rather revealed in our study on megafauna by community composition of this region, which was slightly different from that of all the other regions.…”

Spring-to-summer changes and regional variability of benthic processes in the western Canadian Arctic

“…The influence of predation has neither been investigated in our study area nor suggested to limit the increase in biomass in other polar regions Renaud 1997, Bluhm andGradinger 2008). Moreover, faunal composition also responds to environmental changes on time scales greater than 1 year (Cusson et al 2007;Piepenburg et al 2010) and does, therefore, integrate the effects of past processes that have not been covered during our sampling. It is noteworthy that spatial patterns of biomass did not match those of sediment pigment concentration or carbon remineralisation as can often be expected in polar regions (e.g.…”

“…The southeastern Beaufort Sea is one of the most diverse Arctic shelf regions (Piepenburg et al 2010). Local community composition can be quite variable (Cusson et al 2007), which involves changes in trophic positions and, therefore, in carbon cycling efficiency (Tamelander et al 2006;Sun et al 2009). A better proxy than mere biomass would be achieved if functional Polar Biol (2011) 34:2025-20382033 123 composition of benthic communities were considered in the analysis (Bolam et al 2002;Michaud et al 2005), and hence, we coarsely separated biomass into infauna and foraminifera for analysis of driving factors.…”

Current state and trends in Canadian Arctic marine ecosystems: II. Heterotrophic food web, pelagic-benthic coupling, and biodiversity

“…The low historic sampling effort (1955-1977 period) in the Canadian Arctic (see compilation in Cusson et al 2007), equivalent to~52 m 2 of seafloor, comprised 992 taxa. This compares to 1044 taxa compiled on the Atlantic coast with a three times larger sampling effort (~178 m 2 ).…”