Fine-resolution land cover mapping over large and mountainous areas for Lāna‘i, Hawaii using posterior probabilities, and expert knowledge

Figures & data

Table 1. Description of land cover class categories considered in our study.

Pixel value	Species-specific class	Class description	Community-specific class
1	Aalii native shrubland	ʻAʻaliʻi (Dodonaea viscosa) shrubland is a widespread native community on dry slopes across the island. It includes other native species as well.	Dry native shrubland
2	Albizia	Albizia (Falcataria moluccana) is an invasive tree that occurs across mid-elevation mesic slopes and can shade native species with its large, tall canopy.	Mesic mixed forest
3	Bare earth	Exposed soil. Introduced ungulates have caused massive soil degradation across the island, hence mapping and monitoring of this damage, and potential recovery is a priority.	Unvegetated
4	Brazilian pepper	Brazilian pepper (Schinus terebinthifolia) can form dense clumps in dry areas across the island and is a problematic invasive.	Dry invasive forest
5	Cook pine	Cook pine (Araucaria columnaris) was introduced across mesic high-elevation areas early last century to increase fog water capture. Stands of cook pine persist decades later.	Mesic mixed forest
6	Eucalyptus	Several Eucalyptus and other species in the myrtle family were introduced in the early 20th century to help revegetate degraded lands across the state. These now pose a threat to valuable native mesic communities as they continue to spread across the landscape.	Mesic mixed forest
7	Formosan koa	Formosan koa (Acacia confusa) can form dense stands in dry areas that leave little space for native species to grow.	Dry invasive forest
8	Ironwood	Ironwood (Casuarina sp.) stands occur in dry areas, forming dense litter beneath them where few other plants can thrive.	Dry invasive forest
9	Kiawe, Klu, and Koa haole	Kiawe (Neltuma pallida) can form dense stands in dry areas near the coast where it can access deep ground water resources. In Lāna‘i, klu (Vachellia farnesiana) and koa haole (Leucaena leucocephala) occur within these same environments and are hard to distinguish even with high-resolution imagery.	Dry invasive forest
10	Kukui	Kukui (Aleurites moluccanus), is a non-invasive tree introduced by Polynesians that has multiple uses and strong connections to Hawaiian culture.	Mesic mixed forest
11	Mixed non-native grass and shrubs	Multiple dry areas across Lāna‘i are covered by a mix of invasive grasses and invasive shrubs such as lantana (Lantana camara). These were combined into a single class since individual species differentiation from available imagery was not possible.	Dry invasive grassland
12	Non-native grassland	Non-native invasive grasslands, covering a large portion of the island’s dry environment.	Dry invasive grassland
13	Strawberry guava	Strawberry guava (Psidium cattleyanum) which is major threat to mesic and wet forests statewide and to remaining native mesic vegetation at high elevations on Lāna‘i.	Mesic mixed forest
14	Talus	Rocky areas that lack vegetation cover on the sides of the steep valleys and gorges at mid- and high- elevation across the island.	Unvegetated
15	Uluhe and Ohia	Open uluhe (Dicranopteris linearis) and ʻōhiʻa lehua (Metrosideros polymorpha) forests comprise a valuable native vegetation cover in high-elevation mesic areas. These species provide habitat for other native species, making their extent and distribution important information to guide conservation actions across multiple taxa.	Mesic native forest

Figure 1. Map of collected ground control polygons segmented by a 250 m grid (purple polygons) and points used for independent validation of model results (refer to Section 2.7).

Table 2. Accuracy metrics by class for the species-specific land cover classification for the island of Lāna‘i. Prevalence refers to the proportion of actual positive cases (for a particular class) across the evaluation dataset. Detection prevalence refers to the proportion of predicted positive cases (for a particular class) across the evaluation dataset. Balanced accuracy is (sensitivity+specificity)/2.

Species	Sensitivity	Specificity	Prevalence	Detection Prevalence	Balanced Accuracy
Aalii native shrubland	0.92	1.00	0.04	0.03	0.96
Albizia	1.00	1.00	0.03	0.03	1.00
Bare earth	1.00	1.00	0.12	0.13	1.00
Brazilian pepper	0.89	1.00	0.05	0.05	0.95
Cook pine	0.67	1.00	0.02	0.01	0.83
Eucalyptus	0.93	0.99	0.08	0.08	0.96
Formosan koa	0.88	1.00	0.05	0.04	0.94
Ironwood	0.98	0.99	0.12	0.12	0.98
Kiawe, kluu, and koa haole	1.00	1.00	0.19	0.19	1.00
Kukui	1.00	1.00	0.00	0.01	1.00
Mixed non-native grass and shrubs	1.00	0.99	0.06	0.07	1.00
Non-native grassland	0.95	1.00	0.11	0.10	0.97
Strawberry guava	0.88	1.00	0.02	0.02	0.94
Talus	1.00	1.00	0.07	0.07	1.00
Uluhe and ohia	1.00	1.00	0.04	0.04	1.00

Figure 2. Species-specific land cover map for the island of Lāna‘i, based on expert-adjusted class posterior probabilities. Masked areas under the triangular polygons were infrastructure areas excluded from the analysis (Lāna‘i City, airport and other infrastructure). Example zoomed in areas are provided in appendices 10 and 11.

Figure 3. Example of individual class cover percent probability for the uluhe and ohia cover class.

Table 3. Species-specific land cover area by class for the island of Lāna‘i, based on land cover classification including expert-adjusted class posterior probabilities.

	Area (km^2)	Percent land area
Aalii native shrubland	24.6	7.04
Albizia	1.4	0.41
Bare earth	59.1	16.91
Brazilian pepper	7.5	2.13
Cook pine	3.6	1.03
Eucalyptus	13.5	3.88
Formosan koa	6.4	1.83
Ironwood	9.3	2.67
Kiawe, Ku, and Koa haole	61.8	17.68
Kukui	0.7	0.21
Mixed non-native grass and shrubs	54.4	15.56
Non-native grassland	73.1	20.92
Strawberry guava	2.2	0.63
Talus	27.2	7.78
Uluhe and ohia	4.6	1.33

Figure 4. Community-specific land cover map for the island of Lāna‘i, based on land cover classification including expert-adjusted class posterior probabilities. Masked areas under the triangular polygons were infrastructure areas excluded from the analysis (Lāna‘i City, airport and other infrastructure).

Figure 5. Mixed hierarchical land cover map for the island of Lāna‘i, based on land cover classification including expert-adjusted class posterior probabilities. Masked areas under the triangular polygons were infrastructure areas excluded from the analysis (Lāna‘i City, airport and other infrastructure). Map inset shows a high-elevation area with a mixture of species- and community-specific classes.

Data availability statement

The associated data release for this manuscript and associated metadata is available publicly at Berio Fortini (2024).