Using Geographical Overlaps to Track Temporal Changes in Species Interactions and Community Coexistence Instability

Yin-Zheng Lai,Chih-Hao Hsieh,Chia-Ying Ko,Chih-Wei Tu

doi:10.3389/fmars.2022.751094

Abstract

Environmental and climatic changes are expected to redistribute species, altering the strengths of species interaction networks; however, long-term and large-scale evaluations remain elusive. One way to infer species interaction networks is by analyzing their geographical overlaps, which provides indices of species interdependence, such as mean spatial robustness (MSR), which represents the geographical impact of a species on other species, and mean spatial sensitivity (MSS), which indicates how a species is influenced by other species. Integrating MSR and MSS further allows us to assess community coexistence stability and structure, with a stronger negative relationship between MSR and MSS (i.e., species are unequally dependent on each other) within a community at a given time suggesting a more stable community. Here, we assessed multidecadal changes in adult marine fish communities using bottom trawl datasets across latitudes from 1982 to 2011 in the Eastern US Continental Shelf, North Sea, and Eastern Bering Sea. Consistent, significant long-term increasing temporal trends of MSR and MSS were found in all three large marine communities. MSR exhibited strong correlations with species’ range sizes, especially in high-latitude communities, while MSS was strongly positively correlated with species’ median proportion of overlap with interacting species. The relationships between MSR and MSS were generally negative, indicating stably coexisting fish communities. However, the negative relationships weakened over time, implying that the coexisting fish communities gradually became unstable. Our findings provide an assessment of changes in spatially geographical aspects of multiple species, for decades and at mid- to high latitudes, to allow the detection of global ecological changes in marine systems by alternative estimation of geographic overlaps of species interaction networks. Such species co-occurrence estimation can help stay vigilant of strategies for accelerating climate change mitigation particularly at coarser spatial scales.

Highlights

Species interactions play an important role in determining both species- and community-level responses to environmental and climatic changes, resulting in compositional changes and reorganization and leading to a high risk of ecological imbalance and changes in the dynamics of ecosystem functioning (Parmesan and Yohe, 2003; Walther, 2010; Singer et al, 2013; Goldenberg et al, 2018)
An alternative approach for inferring species interactions is constructing possible species co-occurrence networks describing the geographic overlap of co-occurring species, i.e., the higher species interaction would exist if species overlap, despite debates about the relationship between cooccurrences and ecological interactions (Araújo et al, 2011; Blanchet et al, 2020; Münkemüller et al, 2020)
We found significant long-term increasing trends based on the medians over the 30-year period in both mean spatial robustness (MSR) and mean spatial sensitivity (MSS) of fish species in the three large marine communities: the Eastern US Continental Shelf, the North Sea, and the Eastern Bering Sea

Summary

Introduction

Species interactions play an important role in determining both species- and community-level responses to environmental and climatic changes, resulting in compositional changes and reorganization and leading to a high risk of ecological imbalance and changes in the dynamics of ecosystem functioning (Parmesan and Yohe, 2003; Walther, 2010; Singer et al, 2013; Goldenberg et al, 2018). Increasing numbers of studies have demonstrated impacts of environmental and climatic changes on multiple types of species interactions within communities, in terrestrial (Tylianakis et al, 2008; Lee et al, 2019) and marine microbial ecosystems (Fuhrman et al, 2015). Long-term and large-scale estimates of such species interaction consequences in higher-trophic-level marine fish communities remain scarce due to limited underwater technology, personpower, and financial requirements (Cazelles et al, 2016; Pulver et al, 2016; Sander et al, 2017; Freilich et al, 2018). The advantages of such species co-occurrence estimation has revealed its inclusiveness, including the use of presence-absence, abundance, and fishery observational data; its high applicability in testing a range of ecological and evolutionary hypotheses, from individualistic extinction to the degree of connectance by asymmetrical interactions in communities; and its utility as a fishery management tool for choosing multispecies quota allocations (Williams et al, 2014; Freilich et al, 2018; Griffith et al, 2018)

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