Cumulative disturbances to assess forest degradation using spectral unmixing in the northeastern Amazon

Abstract

Question Tropical forests are subject to disturbances by logging, gathering of fuelwood, and fires. Can degradation trajectories (i.e. cumulative disturbances events over a period of timer) be identified using remote‐sensing Landsat time series? Location Paragominas (Pará, Brazil), a municipality covering 19,395 km² in the north‐eastern Amazon. Methods We used Landsat annual imagery from 2000 to 2015 and spectral mixture analysis to derive time series of the fraction of soil (S), active photosynthetic vegetation (PV), and non‐photosynthetic vegetation (senescent) (NPV) indicators. Results The NPV values over a 16‐year period revealed five different degradation trajectories (i.e., cumulative disturbances in space and over time): undisturbed forest, selectively logged forest (with a management plan), overlogged forest (no management plan), overlogged forest (charcoal production) and burned forest. The variance of NPV calculated per pixel over the same period is useful to map forest degradation over Paragominas municipality, highlighting the role of disturbance factors (logging, fuelwood gathering and fire). Conclusions The fractional cover of NPV obtained from spectral mixture analysis can be used to differentiate degradation trajectories and to map forest degradation.

Lessons for Jurisdictional Approaches From Municipal-Level Initiatives to Halt Deforestation in the Brazilian Amazon

“…PGM is an old frontier where deforestation started in the 1960s, mostly linked to the construction of Belém-Brasília road. By 2005, 42% of the municipal area was deforested and a significant proportion of the remaining forests was undergoing degradation (Hasan et al, 2019). By contrast, by 2005, SFX represented a new frontier with only 16% of accumulated deforestation.…”

“…In the third stage, deforestation rates remained very low (below 25 km 2 per year) and the aim of PGM moved to improve local economy dynamics. Moreover, other ecological challenges emerged, especially fires and forest degradation (Hasan et al, 2019) which led to the need to combine more efficient production systems, incentive mechanisms and forest restoration initiatives (Osis et al, 2019). In 2015, 28 properties with forest reserves deficits were allowed to become regularized through civil law contracts with landowners with forest surpluses in the same municipality (Brito, 2019).…”

Decellularization: Leveraging a Tissue Engineering Technique for Food Production

“…6 Additionally, conventional methods to increase meat production result in damage to the environment in the form of deforestation and loss of biodiversity. 7 There is a clear need for a new method of producing meat that significantly reduces the environmental impact associated with conventional meat production while simultaneously meeting the growing demand. Many alternative protein sources have been proposed, including algae, insects, and plants.…”

“…Projections suggest that current meat production methods are unsustainable and will fail to meet demand around the year 2050 . Additionally, conventional methods to increase meat production result in damage to the environment in the form of deforestation and loss of biodiversity . There is a clear need for a new method of producing meat that significantly reduces the environmental impact associated with conventional meat production while simultaneously meeting the growing demand.…”

Gated Autoencoder Network for Spectral–Spatial Hyperspectral Unmixing

“…Thus, spectral unmixing (SU) [1][2][3][4][5] was proposed to decompose the mixed pixels into a set of substance spectra, called endmembers, and their corresponding fractions, called abundances. SU is generally used as a preprocessing step to provide rich pixel features for downstream tasks [6][7][8][9], or can be adopted directly as a method for substance identification [10].…”