[PCA] 2 ARTICLES: On the positive synergistic biodiversity outcomes by large-scale plant habitat connectivity

[De Angelis, Patricia]

CONNECTING OUR DWINDLING NATURAL HABITATS COULD HELP PRESERVE PLANT
DIVERSITY
During a huge, 18-year experiment, linked areas had greater biodiversity
than isolated patches
By Jonathan Lambert
ScienceNews
SEPTEMBER 26, 2019 AT 2:00 PM

An ecological experiment so big it can be seen from space suggests that
connecting isolated habitats with natural corridors can help preserve plant
diversity.

The 18-year-long project revealed that linking fragments of restored
longleaf pine savanna by a natural passageway boosted the number of plant
species by 14 percent in those patches by the end of the experiment (see
article below). This increase stems from higher plant colonization rates
and lower extinction rates in connected versus unconnected fragments,
researchers report in the Sept. 27 Science.

“This study shows that corridors can, in principle, have lasting, positive
effects on shrinking ecosystems,” says Jens Åström, an ecologist at the
Norwegian Institute for Nature Research in Trondheim who wasn’t involved in
the study. “It’s rare to have ecological experiments viewable from Google
Earth,” he says.

Link: https://rb.gy/c29cf4
ONGOING ACCUMULATION OF PLANT DIVERSITY THROUGH HABITAT CONNECTIVITY IN AN
18-YEAR EXPERIMENT
By Ellen I. Damschen, Lars A. Brudvig, Melissa A. Burt, Robert J. Fletcher
Jr., Nick M. Haddad, Douglas J. Levey, John L. Orrock, Julian Resasco,
Joshua J. Tewksbury
Science
27 Sep 2019

HABITAT CONNECTIVITY ENHANCES DIVERSITY
Fragmentation of ecosystems leads to loss of biodiversity in the remaining
habitat patches, but retaining connecting corridors can reduce these
losses. Using long-term data from a large, replicated experiment, Damschen
et al. show quantitatively how these losses are reduced. In their pine
savanna system, corridors reduced the likelihood of plant extinction in
patches by about 2% per year and increased the likelihood of patch
colonization by about 5% per year. These benefits continued to accrue over
the course of the 18-year experiment. By the end of monitoring, connected
patches had 14% more species than unconnected patches. Restoring habitat
connectivity may thus be a powerful technique for conserving biodiversity,
and investment in connections can be expected to magnify conservation
benefit.

ABSTRACT
Deleterious effects of habitat fragmentation and benefits of connecting
fragments could be significantly underestimated because changes in
colonization and extinction rates that drive changes in biodiversity can
take decades to accrue. In a large and well-replicated habitat
fragmentation experiment, we find that annual colonization rates for 239
plant species in connected fragments are 5% higher and annual extinction
rates 2% lower than in unconnected fragments. This has resulted in a
steady, nonasymptotic increase in diversity, with nearly 14% more species
in connected fragments after almost two decades. Our results show that the
full biodiversity value of connectivity is much greater than previously
estimated, cannot be effectively evaluated at short time scales, and can be
maximized by connecting habitat sooner rather than later.

Link: https://science.sciencemag.org/content/365/6460/1478
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