A New Combined Index to Assess the Fragmentation Status of a Forest Patch Based on Its Size, Shape Complexity, and Isolation

Abstract

There are many local fragmentation metrics, but most can be grouped into four types (composition/area, isolation, edge, and shape), and none of them alone determines the degree of fragmentation of a patch. Here, we grouped together the main fragmentation metrics (area, edge, shape, and isolation) in order to propose a new metric/index, the Patch Fragmentation Index (PFI), with which to determine fragmentation at patch scale. The index was subsequently verified with the Ecuadorian seasonal dry forest by employing geographic information layers and temporal land uses changes in 1990, 2000, 2008, and 2018. The PFI was applied to calculate the fragmentation per patch, spatial and temporal changes of fragmentation based on PFI were assessed, and the spatial patterns (Getis-Ord Gi * analysis) were calculated. The Ecuadorian seasonal dry forest obtained a mean PFI value of 0.88 (median = 0.99) in 2018. This value has increased by 8.6% since 1990, and 3451 patches of forest disappeared between 1990 and 2018. The Getis-Ord Gi * analysis was effective with regard to describing the spatial patterns, and 62% of the patches that were classified as hot patches in 1990 had disappeared by 2018. The PFI has proven to be a useful tool with which to describe fragmentation patterns at patch scale (regardless of its size) and can be extrapolated to other landscapes. The PFI will provide a new vision and can help in the decision-making related to the conservation and management of fragmented ecosystems.

Forest Fragmentation and Landscape Connectivity Changes in Ecuadorian Mangroves: Some Hope for the Future?

“…It is always important to carry out multi-temporal studies for a better perspective on land use during the period under study. As a result, understanding the temporal evolution of fragmentation is extremely helpful when making decisions and determining the drivers causing fragmentation processes [46]. In this study, it was evident that mangrove forests recovered in some locations in Ecuador.…”

“…However, this was because fragmentation has been studied in very homogeneous mangrove ecosystems growing in coastal areas or estuaries. Classical fragmentation metrics may not be very efficient in these types of ecosystems [46], which could explain why the RFI was high in the best-conserved provinces.…”

Uncrewed aerial vehicle-based assessments of peatland permafrost vulnerability along the Labrador Sea coastline, northern Canada

“…PFI, an index of landform fragmentation, was used to assess permafrost patch fragmentation at each study site. Fifteen out of the twenty study sites had a PFI over 0.8, which is considered a very high level of fragmentation (Rivas et al, 2022). Four sites had PFIs between 0.6 and 0.79, considered to be highly fragmented, and one site (CW1) had a PFI index value in the medium fragmentation category (0.4 to 0.59).…”

“…where Ap is total patch area, Ai (area of influence) is the total area that the landform could have covered if it had not undergone fragmentation or degradation, and MPFD is the mean patch fractal dimension (McGarigal & Marks, 1995;Rivas et al, 2022). The total area of the bog captured within the survey was used to approximate Ai (Figures S21-S40), and parts of the bog not captured in the survey were excluded, since permafrost abundance in these areas is unknown.…”

Assessing Spatio-Temporal Variation and Associated Factors of Forest Fragmentation from Morphological Spatial Pattern Analysis and Geo-Detector Analyses: A Case Study of Xinyu City, Jiangxi Province of Eastern China

“…Based on the relevant studies [67][68][69] and the experimental comparisons, we reclassified the forest fragmentation severity of each analytical unit into five grades: low fragmentation, above-low fragmentation, medium fragmentation, sub-high fragmentation, and high fragmentation, by following the criteria of natural breakpoint reclassification.…”