Hydrological Season Can Have Unexpectedly Insignificant Influences on the Elevational Patterns of Functional Diversity of Riverine Macroinvertebrates.

Qingyi Luo,Ming-Chih Chiu,Qinghua Cai,Lu Tan

doi:10.3390/biology11020208

Abstract

Simple SummaryFreshwater ecosystems are increasingly affected by climate dynamics. This study is the first to explore the seasonal effects on the spatial patterns in functional diversity along an elevational gradient. The results showed that the pattern of functional diversity of riverine macroinvertebrates along the elevation gradient was either unimodal or monotonically decreasing. Seasonal changes did not affect the elevational patterns. The findings provide important research and management tools for the temporary effects of river ecosystems.Spatial biodiversity is a key issue in biogeography for the explorations of biological origin and diversification. However, seldom studies have addressed the temporal changes in spatial patterns of biodiversity. We explored the taxonomic and functional diversities of riverine macroinvertebrates in central China, with the elevational gradient, in different seasons in a normal climate year (i.e., no extreme anomalies in the annual precipitation or average annual temperature). The air temperature and streamflow discharge were decreased monotonically with the increase of elevation both in the dry and wet seasons. In addition, the total nitrogen had no significant change with the increase of elevational gradient in the dry season but showed a monotonically decreasing pattern in the wet season. The total phosphorus showed a monotonically decreasing pattern with the elevational gradient in the dry season but had no significant change in the wet season. The spatial pattern of taxonomic diversity of macroinvertebrates along the elevational gradient showed complex patterns, but the functional diversity had either the unimodal or monotonically decreasing pattern. In addition, the functional diversity with the elevational gradient had similar patterns between the dry and wet seasons. Further analysis of the elevational pattern in different seasons is an important basis for understanding the status quo of functional diversity and formulating countermeasures for biodiversity conservation.

Highlights

How biodiversity changes along spatial gradients is a key issue in biogeography for empirical and theoretical explorations of biological origin and diversification [1–3]
Environmental Factors along the Elevational Gradient. In both the dry and wet seasons, elevation had a significant effect on discharge (p < 0.05), while elevation had no significant effect on total nitrogen, total phosphorus, and air temperature (Table 2)
The total nitrogen had no significant change with the increase of elevational gradient in the dry season but showed a monotonically decreasing pattern in the wet season

Summary

Introduction

How biodiversity changes along spatial gradients is a key issue in biogeography for empirical and theoretical explorations of biological origin and diversification [1–3]. The influences of elevation on the structure of biological communities play vital roles in the drivers of global biodiversity [4,5]. Research on the biodiversity along elevational gradients mainly focuses on taxonomic diversity [6]. In terms of ecosystem functions, studies based on biological traits can provide more information than studies merely on species diversity [8]. Using biological traits to represent functional composition and diversity is one of the hotspots in ecological research, e.g., for macroinvertebrates [9]. The functional traits have been proven to serve as a promising proxy of the community or ecosystem functions in response to the various types of disturbances [10–12]

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