Ecological data from: Combining botanical collections and ecological data to better describe plant community diversity

In this age of rapid biodiversity loss, we must continue to refine our
approaches to describing variation in life on Earth. Combining knowledge
and research tools from multiple disciplines is one way to better describe
complex natural systems. Understanding plant community diversity requires
documenting both pattern and process. We must first know which species
exist, and where (i.e., taxonomic and biogeographic patterns), before we
can determine why they exist there (i.e., ecological and evolutionary
processes). Floristic botanists often use collections-based approaches to
elucidate biodiversity patterns, while plant ecologists use
hypothesis-driven statistical approaches to describe underlying processes.
Because of these different disciplinary histories and research goals,
floristic botanists and plant ecologists often remain siloed in their
work. Here, using a case study from an urban greenway in Colorado, USA, we
illustrate that the collections-based, opportunistic sampling of floristic
botanists is highly complementary to the transect- or plot-based sampling
of plant ecologists. We found that floristic sampling captured a community
species pool four times larger than that captured using ecological
transects, with rarefaction and non-parametric species estimation
indicating that it would be prohibitive to capture the “true” community
species pool if constrained to sampling within transects. We further
illustrate that the discrepancy in species pool size between approaches
led to a different interpretation of the greenway’s ecological condition
in some cases (e.g., transects missed uncommon cultivated species escaping
from nearby gardens) but not others (e.g., plant species distributions
among functional groups were similar between species pools). Finally, we
show that while using transects to estimate plant relative abundances
necessarily trades off with a fuller assessment of the species pool, it is
an indispensable indicator of ecosystem health, as evidenced by three
non-native grasses contributing to 50% of plant cover along the highly
modified urban greenway. We suggest that actively fostering collaborations
between floristic botanists and ecologists can create new insights into
the maintenance of species diversity at the community scale.