Long-range ecosystem sensing: biodiversity monitoring from space By Joe Mascaro

December 9, 2015 PLOS Blogs Conservation Ecology

The above image by Kreg Steppe (creative commons license).

“Mr. Data… can you find a way to scan for lifeforms?”

“I would be happy to, Sir. I just love scanning for lifeforms!”

Like many of Star Trek’s famed gadgets, the long-range sensors of the sci-fi series seemed like a black box or voodoo magic. As soon as the USS Enterprise entered orbit, the crew suddenly gleaned everything they needed to know about life below. Multicellular blob creatures. Sentient abandoned mining equipment. Energetic populations with suspect governance.

Meanwhile on Earth, monitoring the status of ecosystems—and especially their biological diversity—has been a nettlesome task. Ultimately, human welfare is wrapped up in that of Earth’s ecosystems. Without a functioning biosphere, our civilization would not be possible.

And while there remains no consensus estimate for the number of species that inhabit our planet, thousands have either gone extinct or become threatened or endangered in recent centuries.

Humans now use more than half of the biosphere’s productivity, co-opting habitat formerly used by the remainder of Earth’s species. And although the vast majority of species on Earth are physically too small to be resolved from space, the signature of humanity’s reach over the land-surface is laid out in full view. Our cities, farms and pastures can be seen where savannas and forests once stood.

Two recent articles, led by ecologists, have argued for an expanded role of space-based remote sensing in monitoring biological diversity. In July, Skidmore and colleagues argued that ecologists and government space agencies must agree upon key biodiversity metrics to track from space. In October, Pimm and colleagues also touted remote sensing as a quintessential tool in the biodiversity crisis. These pieces are timely. Yet, alignment between ecologists and space agencies may not be enough to get the satellites in space needed to do the job.

Space is hard and space is expensive.

Many earth observation spacecraft have been canceled or delayed by launch failures or political roadblocks. And those that do make it to orbit are often limited in their technological power because of the enormous time taken to get to space.

The launch of DSCOVR, after more than a decade of delay, is the most recent example: it spent most of its life on the ground as a political football of epic proportions. The Orbiting Carbon Observatory failed to make orbit in 2009 and required an additional $465M and five years to be successfully deployed. In that time, eleven ppm of CO2 were added to the atmosphere. The Glory spacecraft, designed to monitor particulate carbon in the atmosphere—which alters incident light on the Earth’s surface—was also a recent victim of launch failure. The DESDynI mission, built to measure the physical structure of the world’s forests and understand their carbon emissions, fell to budget cuts. For nearly 50 years, the NASA/USGS Landsat system has ostensibly watched ecosystems change at 30m spatial resolution, every 16 days.

Endeavour and Earth's Horizon from NASA's Marshall Space Flight Center (creative commons license). — *Endeavour and Earth’s Horizon from NASA’s Marshall Space Flight Center (creative commons license).*

But for many types of change, this level of spatial and temporal detail is just too low. Consider a disaster comparable to Superstorm Sandy, which strikes large cities and wipes out power for several days: the relatively low spatial and temporal resolution would mean that only certain types of damage are clearly detected. Landsat doesn’t clearly resolve most buildings, powerlines, or roads in urban areas. And its limitations are also felt when looking at ecosystems. Over multi-year time scales, large-scale deforestation looks straightforward. But the small-scale, frenzied road-building and selective logging that drives the leading edge of deforestation is often subsumed within a single Landsat pixel, or blocked out by clouds. And thus, efforts to alert enforcement agencies to illegal logging lag behind.

But in the face of these political, logistical and technological challenges, a revolution in space-based assessment and monitoring of ecosystems is underway.

Collectively, the commercial remote sensing community has the near-term potential to solve the fundamental problems identified by Skidmore and colleagues: “…inadequate access to satellite data; uncertainties in the continuity of satellite observations; and temporal and spatial limitations of satellite imagery.”

Working backwards, temporal and spatial fidelity have each dramatically increased in recent years.

By the end of 2016, Planet Labs will image the whole terrestrial surface of the Earth at approximately 4m resolution every day.

*A fire spreads in the Omo River Delta, on the north shore of Lake Turkana (photo courtesy of Planet Labs).*

Ecosystem change, on a daily cadence, will be visible in these data. DigitalGlobe and Skybox (a division of Google) can target portions of the Earth’s surface for imaging at sub-meter resolution, revealing palm fronds and even individual livestock, albeit at lower temporal cadence. Together, these datasets can give ecologists and conservationists the temporal and spatial information they need to characterize threats and intervene in a timely fashion. These private sector organizations provide continuity of space-based observations of ecosystems that can help scientists monitor changes in ecosystems and their embedded biodiversity.

In the past, both logistical and governance challenges have prevented even the coarse resolution public data from ever being downloaded and analyzed. Access to information from new commercial long-range ecosystem sensors is now the most important challenge.

In human crises, such as the recent Earthquake in Nepal, commercial providers typically open up their data archives to enhance humanitarian efforts.

The biodiversity crisis should be no different. As the ecology and remote sensing communities continue to work toward a spaceborne biodiversity monitoring strategy, commercial providers must be at the table to determine novel ways to support this timely and important effort.

Joe Mascaro (@joe_mascaro) is a terrestrial ecologist whose work explores the proliferation of novel ecosystems in the Anthropocene. Joe is currently Program Manager for Impact Initiatives at Planet Labs—a San Francisco-based aerospace company that operates the largest fleet of Earth-imaging satellites. At Planet, Joe manages social, environmental, and humanitarian engagement, expanding Planet’s efforts to improve forest monitoring and conservation, enhance food security, and promote ecological resilience for some of the world’s most vulnerable communities.