Data from: Long-term human land-use change throughout Southeast Asia reshapes the distribution of suitable habitat for a human-commensal bird species

Aim: Human activity has reshaped ecological communities for thousands of
years. While these activities have typically led to habitat loss, some
species have successfully exploited human environments. However, the
effects of long-term human land-use on the distributions of such species
are poorly understood. Here, we investigated how land-use change over the
last 12,000 years has altered the distribution of suitable habitat for a
widespread human-commensal bird species, the Pacific swallow (Hirundo
tahitica).  Location: Southeast Asia, Melanesia Methods: We built
species distribution models using community science records and evaluated
approaches to controlling for spatial biases that arise from using
unstructured survey data to model species associated with anthropogenic
environments. We then assessed the distribution of suitable habitat for
Pacific swallows under three alternative scenarios of land-use change that
incorporated only climate variables, only human land-use variables, and
both variable sets. Lastly, we hindcasted alternative models at 1,000-year
intervals over the last 12,000 years to evaluate how habitat availability
has changed due to long-term human activity. Results: Models that included
climate and human land-use variables were the best fit to occurrence
records. Standard methods for controlling for spatial bias performed
poorly compared to fully sampling the environmental background,
highlighting unique considerations for modeling human-associated species.
Hindcasting alternative land-use scenarios showed that suitable
human-altered habitat arose within the Pacific swallow range at least 4000
years ago and caused significant expansions of suitable habitat over the
last 2000 years.  Main conclusions: Human land-use over the last
several thousand years has likely provided Pacific swallows with
substantial new habitat, which may have led to population size expansions.
Incorporating long-term human land-use into species distribution models
offers insights into when associations with human environments may have
arisen and generates testable predictions for how populations respond and
adapt to human land-use change over millennial timescales.