Data from: Unusual but consistent latitudinal patterns in macroalgal habitats and their invertebrate communities across two countries

Aim: The physical characteristics of biogenic habitats and environmental
conditions are important determinants of biodiversity, yet their relative
importance can change across spatial scales. We aimed to understand how
relationships between the physical characteristics of macroalgal habitats
and their invertebrate communities varied across spatial scales and
whether general ecological patterns occurred across two countries.
Location: 18 sites across the temperate east coasts of Australia (over
1,300 km) and New Zealand (over 1,000 km), with the latitudinal gradient
in the two countries overlapping by 6.73 decimal degrees. Time period:
January to early April 2012. Major taxa studied: Three intertidal
macroalgal habitats in each country and the invertebrate communities
within them. Methods: We measured variation in patch- and individual-level
characteristics of macroalgal habitats and their invertebrate communities.
Patterns in macroalgal characteristics and communities were compared
across latitude, and at smaller spatial scales, and correlated with 26
abiotic environmental variables using multiple multivariate analyses.
Results: Separately, macroalgal habitat characteristics and communities
showed unusual but consistent non-linear latitudinal patterns, with
greater similarity among sites at the edges of the sampled distribution
(i.e. north and south) than at centrally-located sites. Macroalgal
characteristics did not correlate with a particular set of environmental
variables, however, communities were structured by sea surface temperature
at the country scale, and by macroalgal habitat type and biomass within
countries. Anthropogenic variables were also important and may have
contributed to the unusual non-linear patterns observed between macroalgal
characteristics and communities across latitude. Main conclusions: Our
results support other studies showing that large-scale patterns can emerge
from systems where there is high local-scale variability. The results show
that communities within macroalgal habitats respond to both the physical
characteristics of the habitat and external environmental conditions (e.g.
temperature). Suggesting that local-scale environmental factors, including
anthropogenic stressors may modulate environmental gradients over larger
scales.