Latitudinal diversity patterns of Chilean coastal fishes: searching for causal processes

Abstract

Background: Several particular aspects of diversity patterns of Chilean littoral fishes are still poorly understood, and existing studies within this scope are fundamentally based on bibliographic compilations. In this study, we use empirical data to assess whether the diversity patterns of fish fauna along 4000 km of the Chilean coast (20°-55°S) can be explained in relation to the environmental latitudinal gradient. Fish were collected from intertidal pools and subtidal habitats (<35 m). Analyses focused on the spatial scales of diversity patterns and latitudinal breaks in species diversity, comparing the observed patterns among intertidal and subtidal habitats. Correlations between variance in environmental factors and species richness were calculated. Results: Richness was positively autocorrelated at spatial scales <1000 km. Overall, richness was observed to progressively decrease toward higher latitudes, but values for intertidal fish in particular decreased towards the north and south from the point of maximum richness. This is a pattern that has already been recorded for other intertidal organisms. Similarity was seen to decrease with distance, and turnover point for intertidal fishes was high around 30°-32°S, while northern species disappeared between 36°-39°S. Subtidally, there is an invasion of subantarctic species between 53°-55°S. Conclusions: Environmental variables are significant to the diversity patterns recorded. However, richness variations could result from many types of variables acting together and not from one single factor.

AnchovetaEngraulis ringensalong the Chilean coast: Management units, demographic units and water masses: Insights from multiple otolith‐based approaches

“…We found evidence of a much greater segregation between both northern units (DU‐I and DU‐II) and the southern unit (DU‐III), than between the two northern units, which is consistent with previous findings based upon parasitological (Valdivia et al, ) and otolith shape markers (Cerna et al, in press). Moreover, it is clearly consistent with the idea that an oceanographic and biogeographic discontinuity exists at the Tropical Convergence, which imposes relevant changes in water masses and community structures (Escribano, Fernández, & Aranís, ; Lancellotti & Vasquez, , ; Navarrete, Lagos, & Ojeda, ; Thiel et al, ). Overall, our results allow for speculating a close link between demographic units and dominant surface water masses (Figure ).…”

Seasonal variation in epifaunal communities associated with giant kelp (Macrocystis pyrifera) at an upwelling‐dominated site

“…In addition, the presence of carnivorous fish predators decreases south of 40°S (Navarrete et al . ) while fish predation in northern‐central Chile is strong (Muñoz & Ojeda ; Pérez‐Matus et al . ), possibly also contributing to the apparent latitudinal differences in species richness within these kelp communities.…”

Intertidal Biogeographic Subprovinces: Local and Regional Factors Shaping Fish Assemblages

“…As local habitat features can influence communities to the degree that they affect regional arrangements, it is imperative understand the underlying processes that determine these patterns (Ricklefs, 1987;Rivadeneira et al, 2002;Arakaki et al, 2014;Navarrete et al, 2014). The processes include biological interactions, such as herbivory, predation, and competition, as well as the effects of the physical environment (Horn and Ojeda, 1999;Arakaki and Tokeshi, 2011;Arakaki et al, 2014;Ahmadia et al, 2018).…”