Altitudinal range shift outpaced intraspecific body size change in shaping community body size structure of Geometrid moths over 42 years of warming
Date Issued
2014
Date
2014
Author(s)
Wu, Chung-Huey
Abstract
Community body size structure (e.g. the distribution or average of body size of different species) is fundamental in determining food web structure, dynamics and stability. This size structure across environmental gradients (e.g. altitude) can be affected by climate warming, because warming has reportedly led to changes in intraspecific body size or species range (affecting species composition), consequently shaping community body size structure. However, few studies examined both mechanisms together, and therefore little is known about whether and how intraspecific body size change and species range shift will collectively affect community body size structure under warming. We collected Geometrid moths in the year of 1965 and 2007 from Mt. Kinabalu (396 species from 1,450 to 3,675 m a.s.l.), which had experienced a 0.7oC warming during these 42 years. This study investigated 1) whether community body size structure (i.e. average interspecific body size) of Geometrid moths across altitude had shifted over the 42 years of warming, 2) whether intraspecific body size had changed under this warming, 3) whether species range shift had occurred, consequently changing species composition, and 4) what is the relative contribution of the two mechanisms above (intraspecific body size change and species range shift) to changes in community body size structure, if any. The results showed that species range shift, instead of intraspecific body size change, significantly contributed to the detected change in community body size structure. In specific, species range shift changed local species composition and reduced both average species body size and average individual body size at high altitude, based on either non-abundance-weighted or abundance-weighted analyses. This altitude-dependent pattern was driven mainly by an increase in the number and population size of upward-shifting species (relatively small body size) and a decrease in the population size of downward-shifting species (relatively large body size). This study is among the first ones to show that species range shift may precede intraspecific body size change in terms of shaping community body size structure under climate warming. In other words, this study provides a warning that we may not observe significant warming impact at lower ecological level (e.g. species-level body size), but warming may have caused significant impact at higher level (e.g. community level) during the same time period (e.g. 42 years in this study).
Subjects
氣候變遷
群聚體型結構
體型
分布範圍變遷
海拔
尺蛾
SDGs
Type
thesis
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