Biogeographical zonation of rocky intertidal communities along the coast of Peru (3.5–13.5° S Southeast Pacific)

Abstract

The biogeography of the Peruvian Eastern Pacific coast has been described based on oceanographic parameters and qualitative species occurrence data. This has generated disagreement about the limits and existence of different biogeographic units. In this study, the distribution of rocky-shore macrobenthic communities were recorded over 41 sites along the Peruvian coastline (3.5°S-13.5°S) and analyzed together with historic abiotic data in order to quantitatively evaluate the biogeographic zonation of rocky intertidal communities throughout the region and its relationship with environmental variables to propose an update bioregionalization. Clusters and non-metric multidimensional scaling were performed using Bray-Curtis dissimilarity matrices from abundance data to evaluate biogeographic patterns of dissimilarities of rocky-shore communities. Significant turnover of taxa among defined biogeographical units was tested using permutational multivariate dispersion. Relationships between of the biogeographical community’s structure and environmental factors were examined using Random Forest analysis on datasets available at Bio-Oracle and Jet Propulsion Laboratory—California Institute of Technology. Variation of community structure of 239 taxa depicted three biogeographical units along the region matching Panamic, transitional and Humboldt provinces. Beta diversity analysis indicated a significant turnover of taxa within the transitional unit. Random forest analysis showed a strong correlation between biogeographic units with phosphate, sea surface temperature, nitrate, dissolved oxygen, cloud fraction, and silicates. Our results set the putative limits of three biogeographic units for rocky-shore communities along the coast of Peru, providing base-line information for understanding further biogeographic changes on communities associated with the ongoing regional coastal cooling and impacts of El Niño events.

On the importance of habitat continuity for delimiting biogeographic regions and shaping richness gradients

“…For example, depending on the habitat specificity of the group of species in question, if habitat is sparse within regions spanning mid to low latitudes where temperate climates coincide with subtropical/tropical climates, then species turnover across these regions may be particularly abrupt due to a combination of thermal stress and low habitat availability, resulting in a biogeographic boundary. Such boundaries should also mark a steep richness gradient given that tropical regions are expected to be more species rich than extratropical regions (Edgar et al 2017;Ibanez-Erquiaga et al 2018;Kinlock et al 2018). Likewise, if biogeographic boundaries and associated species richness gradients are delimited and shaped, in part, by low habitat continuity (sparse habitat), then, relatively speaking, the central portions of biogeographic regions should be characterised by high habitat continuity (plentiful habitat) and comparatively lower species turnover.…”

Stable isotope and fatty acid analyses reveal significant differences in trophic niches of smooth hammerhead Sphyrna zygaena (Carcharhiniformes) among three nursery areas in northern Humboldt Current System

“…Three nursery areas of smooth hammerhead have been described in the HCS based on the presence and abundance of neonates and juveniles (total length between 53 and 150 cm) (González-Pestana, 2014;González-Pestana, 2018). One is located in the Tropical East Pacific Marine Province (TEP-MP) at approximately 4 • S in proximity of Máncora Port and is characterized by high fish diversity (Spalding et al, 2007;Ibanez-Erquiaga et al, 2018). The other two nursery areas are located in the Warm Temperate Southeastern Pacific Marina Province (WTSP-MP), one at approximately 6 • 40 S in proximity of San José Port and one at approximately at 8 • 15 S in proximity of Salaverry Port (Spalding et al, 2007).…”

Peer Review #1 of "Stable isotope and fatty acid analyses reveal significant differences in trophic niches of smooth hammerhead Sphyrna zygaena (Carcharhiniformes) among three nursery areas in northern Humboldt Current System (v0.2)"

“…Three nursery areas of smooth hammerhead have been described in the HCS based on the presence and abundance of neonates and juveniles (total length between 53 and 150 cm) (González-Pestana, 2014. One is located in the Tropical East Pacific Marine Province (TEP-MP) at approximately 4°S in proximity of Máncora Port and is characterized by high fish diversity (Spalding et al, 2007;Ibanez-Erquiaga et al, 2018) 2020:11:55838:1:1:NEW 1 Mar 2021) Manuscript to be reviewed at approximately at 8°15'S in proximity of Salaverry Port (Spalding et al, 2007). Both of these nursery areas located in WTSP-MP are characterized by high productivity driven by the HCS and high fish biomass and diversity (Chavez et al, 2008;Ibanez-Erquiaga et al, 2018).…”