Harvard Forest >

Harvard Forest Symposium Abstract 2018

• Title: Among-species overlap in rodent body size distributions predicts species richness along a temperature gradient
• Primary Author: Sydne Record (Bryn Mawr College)
• Additional Authors: John Grady (University of New Mexico - Main Campus)
• Abstract:

  Additional co-authors: Quentin Read (Michigan State University), Phoebe Zarnetkse (MSU), Ben Baiser (University of Florida Gainesville), Jonathan Belmaker (Tel Aviv University), Mao-Ning Tuanmu (Academica Sinica), Angela Strecker (Portland State University), Lydia Beaudrot (University of Michigan), and Katherine Thibault (NEON).
  
  Temperature is widely regarded as a major driver of species richness, but the
  mechanisms are debated. Niche theory suggests temperature may affect richness
  by filtering traits and species in colder habitats while promoting specialization in
  warmer ones. However, tests of this theory are rare because niche dimensions are
  challenging to quantify along broad thermal gradients. Here, we use individuallevel
  trait data from a long-term monitoring network spanning a large geographic
  extent to test niche-based theory of community assembly in small mammals. We
  examined variation in body size among 23 communities of North American rodents
  sampled across the National Ecological Observatory Network (NEON), ranging
  from northern hardwood forests to subtropical deserts. We quantified body size
  similarity among species using a metric of overlap that accounts for individual
  variation, and fit a structural equation model to disentangle the relationships
  between temperature, productivity, body size overlap, and species richness. We
  document a latitudinal gradient of declining similarity in body size among species
  towards the tropics and overall increase in the dimensions of community-wide trait
  space in warmer habitats. Neither environmental temperature nor net primary
  productivity directly affect rodent species richness. Instead, temperature determines
  the community-wide niche space that species can occupy, which in turn alters
  richness. We suggest a latitudinal gradient of trait space expansion towards the
  tropics may be widespread and underlie gradients in species diversity.

• Research Category: Physiological Ecology, Population Dynamics, and Species Interactions
  Large Experiments and Permanent Plot Studies
  Biodiversity Studies