Main Text:
The 2022 United Nations Biodiversity Conference (COP-15) addressed five
“horsemen of the biodiversity apocalypse”: climate change, pollution,
invasive species, overexploitation, and land use change. Policies to
regulate land use are especially important because land use contributes
the most to ongoing biodiversity loss (1, 2) . At the same time,
such policies are especially delicate because land use change is
inherently intertwined with how people benefit from and depend on nature(3) .
While land use change continues to increase (2, 4) , the
complexity of species responses to such change has spurred debates on
how to best manage habitat for sustaining biodiversity. For instance,
how often does habitat fragmentation exacerbate or interact with the
effects of habitat loss on biodiversity (5, 6) ? And when can land
sharing be considered alongside land sparing in conservation planning(7, 8) ? Deciding which habitat is most valuable based on its
pattern and amount has proven difficult because different
spatio-temporal scales and ecosystems evaluated in different studies can
generate different answers to analogous questions. These debates might
lead managers and policy makers to believe that scientists cannot agree
on how biodiversity should be preserved in the face of widespread and
increasing global land use.
Ongoing debates should not distract from the areas of consensus reached
after decades of research in biodiversity conservation. We therefore
take this opportunity to share a message of agreement among scientists
who work in this field. We highlight three fundamental principles (Fig.
1):
1) To protect Earth’s biodiversity, we must protect and restore native
habitats in all biomes and ecoregions (Fig. 1.1). This will safeguard
the unique contribution of each ecoregion to our biological heritage.
Biodiversity has intrinsic value and is not fungible; this must be kept
in mind, especially as the world weighs biodiversity credits.
2) Protecting as much native habitat as possible is our best way to
safeguard biodiversity (Fig. 1.2). The total area of habitat is
paramount, and includes both the remaining large native ecosystems and
the many small native patches in human-dominated regions. Habitat
restoration will be especially important to reach minimum area targets
in regions where most native habitat has already been converted to human
land uses.
3) Habitat patches must be functionally connected (Fig. 1.3).
Connectivity ensures access to sufficient and complementary resources
when habitat patches are too small for a single patch to sustain a
species. Connectivity is also fundamental when patches are larger, as
migration between them decreases population extinction risk, facilitates
re-colonization, and may allow species to shift their ranges in response
to shifting climate.