Data for Body mass-related changes in mammal community assembly patterns during the late Quaternary of North America

The late Quaternary of North America was marked by prominent ecological
changes, including the end-Pleistocene megafaunal extinction, the spread
of human settlements, and the rise of agriculture. Here we examine the
mechanistic reasons for temporal changes in mammal species association and
body size during this time period. Building upon the co-occurrence results
from Lyons et al. (2016) – wherein each species pair was classified as
spatially aggregated, segregated, or random – we examined body mass
differences (BMD) between each species pair for each association type and
time period (Late Pleistocene: 40,000 14C - 11,700 14C ybp, Holocene:
11,700 14C - 50 ybp, and Modern: 50 - 0 yrs). In the Late Pleistocene and
Holocene, the BMD of both aggregated and segregated species pairs was
significantly smaller than the BMD of random pairs. These results are
consistent with environmental filtering and competition as important
drivers of community structure in both time periods. Modern assemblages
showed a breakdown between BMD and co-occurrence patterns: the average BMD
of aggregated, segregated, and random species pairs did not differ from
each other. Collectively, these results indicate that the late Quaternary
mammalian extinctions not only eliminated many large- bodied species but
were followed by a re-organization of communities that altered patterns of
species coexistence and associated differences in body size.