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As humans continue to alter Earth systems, conservationists look to remote sensing to monitor, inventory, and understand ecosystems and ecosystem processes at large spatial scales. Multispectral remote sensing data are commonly integrated into conservation decision-making frameworks, yet imaging spectroscopy, or hyperspectral remote sensing, is underutilized in conservation. The high spectral resolution of imaging spectrometers captures the chemistry of Earth surfaces, whereas multispectral satellites indirectly represent such surfaces through band ratios. Here, we present case studies wherein imaging spectroscopy was used to inform and improve conservation decision-making and discuss potential future applications. These case studies include a broad array of conservation areas, including forest, dryland, and marine ecosystems, as well as urban applications and methane monitoring. Imaging spectroscopy technology is rapidly developing, especially with regard to satellite-based spectrometers. Improving on and expanding existing applications of imaging spectroscopy to conservation, developing imaging spectroscopy data products for use by other researchers and decision-makers, and pioneering novel uses of imaging spectroscopy will greatly expand the toolset for conservation decision-makers.

Imaging spectroscopy is a burgeoning tool for understanding ecosystem functioning on large spatial scales, yet the application of this technology to assess intra-specific trait variation across environmental gradients has been poorly tested. Selection of specific genotypes via environmental filtering plays an important role in driving trait variation and thus functional diversity across space and time, but the relative contributions of intra-specific trait variation and species turnover are still unclear. To address this issue, we quantified the variation in reflectance spectra within and between six uniform stands of Metrosideros polymorpha across elevation and soil substrate age gradients on Hawai‘i Island. Airborne imaging spectroscopy and light detection and ranging (LiDAR) data were merged to capture and isolate sunlit portions of canopies at the six M. polymorpha-dominated sites. Both intra-site and inter-site spectral variations were quantified using several analyses. A support vector machine (SVM) model revealed that each site was spectrally distinct, while Euclidean distances between site centroids in principal components (PC) space indicated that elevation and soil substrate age drive the separation of canopy spectra between sites. Coefficients of variation among spectra, as well as the intrinsic spectral dimensionality of the data, demonstrated the hierarchical effect of soil substrate age, followed by elevation, in determining intra-site variation. Assessments based on leaf trait data estimated from canopy reflectance resulted in similar patterns of separation among sites in the PC space and distinction among sites in the SVM model. Using a highly polymorphic species, we demonstrated that canopy reflectance follows known ecological principles of community turnover and thus how spectral remote sensing addresses forest community assembly on large spatial scales.

Imaging spectroscopy has the potential to map closely related plant taxa at landscape scales. Although spectral investigations at the leaf and canopy levels have revealed relationships between phylogeny and reflectance, understanding how spectra differ across, and are inherited from, genotypes of a single species has received less attention. We used a common-garden population of four varieties of the keystone canopy tree, Metrosideros polymorpha, from Hawaii Island and four F1-hybrid genotypes derived from controlled crosses to determine if reflectance spectra discriminate sympatric, conspecific varieties of this species and their hybrids. With a single exception, pairwise comparisons of leaf reflectance patterns successfully distinguished varieties of M. polymorpha on Hawaii Island as well as populations of the same variety from different islands. Further, spectral variability within a single variety from Hawaii Island and the older island of Oahu was greater than that observed among the four varieties on Hawaii Island. F1 hybrids most frequently displayed leaf spectral patterns intermediate to those of their parent taxa. Spectral reflectance patterns distinguished each of two of the hybrid genotypes from one of their parent varieties, indicating that classifying hybrids may be possible, particularly if sample sizes are increased. This work quantifies a baseline in spectral variability for an endemic Hawaiian tree species and advances the use of imaging spectroscopy in biodiversity studies at the genetic level.

Aim: This paper assesses the relative importance of environmental filtering and dispersal limitations as controls on the western range limit of Fagus grandifolia, a common mesic late-successional tree species in the eastern United States. We also test for differences in species-environment relationships between range-edge populations of F. grandifolia in eastern Wisconsin and core populations in Michigan. Because environmental conditions between the states differ moderately, while in Michigan dispersal presumably no longer limits F. grandifolia distributions, F. grandifolia offers a classic case study for biogeographers, foresters, and palaeoecologists interested in understanding processes governing species range limits.Location: Wisconsin and Michigan, USA. Taxon: Fagus grandifolia.Methods: This study combines historical datasets of F. grandifolia from the Public Land Survey, environmental covariates from soil maps and historical climate data, three spatial scenarios of dispersal limitation, and five species distribution models (SDMs). We test dispersal limitation and environmental filtering hypotheses by assessing SDM transferability between core and edge populations, measuring the importance of dispersal and environmental predictors, and using a residual autocovariate model to test for spatial processes not represented by these predictors.Results: Fagus grandifolia presence was best predicted by total snowfall in Michigan and by dispersal, summer precipitation, and potential evapotranspiration (PET) in Wisconsin. Following the addition of dispersal as a predictor, most Wisconsin models improved and spatial autocorrelation effects largely disappeared. Transferability between core and edge populations was moderate to low. Main conclusions:Both environmental and dispersal limitations appear to govern the western range limit of F. grandifolia. Species-environment relationships differ between range-edge and core populations, suggesting either stronger environmental filtering at the range edge or fine-scale, spatially varying interactions between environmental factors governing moisture availability in core populations. Although lakes, like Lake Michigan, both moderate regional climates and act as dispersal barriers, these effects can be disentangled through the joint analysis of SDMs and historic observational datasets.