## 3 Results
### Performance of VIs  
Leaf hyperspectral response was used to derive the VIs listed in Table 1. Leaf-level relationships were computed between the narrow band VIs and CC. The narrow band VIs with the most explanatory power (\(R^{2}\!>\!0.5\)) were VOG indices, MTCI, mND\({}_{705}\), mSR\({}_{705}\), mCARI\({}_{705}\), and SR\({}_{750}\) (Table 2, Figure 5). When coefficients of determination were computed on a per-species basis, VIs followed the same trend showing an increase in the percentage of explained variation in CC. The best performing narrow band VIs in terms of coefficient of determination for \(R\). _mangle_ were VOG\({}_{2}\), VOG\({}_{3}\), VOG\({}_{1}\), mND\({}_{705}\), and MTCI (Table 3). Similarly, VOG\({}_{2}\), VOG\({}_{3}\), MTCI, VOG\({}_{1}\), and mSR\({}_{705}\) performed best for \(L\). _racemosa_ (Table 4). _A. germinans_ CC had the largest correlation with VOG\({}_{1}\), VOG\({}_{3}\), mCARI705, MTCI, and mND\({}_{705}\) (Table 5), while VOG\({}_{2}\), VOG\({}_{3}\), VOG\({}_{1}\), mCARI\({}_{705}\), and mND\({}_{705}\) best explained CC variation in _C. erectus_ (Table 6). \begin{table}
\begin{tabular}{c c c c c} \hline
**VI** & **Intercept** & **Slope** & \(R^{2}\) & **RMSE** & **Signif.** \\ \hline VOG\({}_{2}\) & 20.382 & \(-\)449.057 & 0.588 & 11.3 & *** \\ VOG\({}_{1}\) & \(-\)77.714 & 91.798 & 0.587 & 11.3 & *** \\ VOG\({}_{3}\) & 22.558 & \(-\)379.752 & 0.582 & 11.4 & *** \\ MTCI & 22.817 & 15.554 & 0.564 & 11.7 & *** \\ mND\({}_{705}\) & \(-\)7.524 & 112.029 & 0.551 & 11.8 & *** \\ mSR\({}_{705}\) & 16.172 & 10.088 & 0.530 & 12.1 & *** \\ mCARI\({}_{705}\) & 22.597 & 35.201 & 0.528 & 12.1 & *** \\ SR\({}_{750}\) & 9.051 & 14.264 & 0.514 & 12.3 & *** \\ TCARI & 82.556 & \(-\)103.717 & 0.457 & 13.0 & *** \\ \hline \end{tabular}
\end{table} 
Table 2: Relationship between CC and VIs (\(n=987\)). Figure 4: Leaf CC (\(\mu\)g\(\cdot\)cm\({}^{-2}\)) for the four mangrove species. Each box embodies the first and the third quartile. The bold line represents the median while the dark dot represents the mean. Whiskers are located at 1.5 times the interquartile range and white dots denote outliers. Significant differences (\(p<0.05\)) were observed between the following pairs: (i) \(R\). _mangle–A. germinans_, (ii) \(L\). _racemosa–C. erectus_, and (iii) \(R\). _mangle–C. erectus_. \begin{table}
\begin{tabular}{c c c c c c} \hline
**VI** & **Intercept** & **Slope** & \(R^{2}\) & **RMSE** & **Signif.** \\ \hline WDRVI green & 15.381 & 65.250 & 0.450 & 13.1 & *** \\ NDVI green & 2.228 & 92.202 & 0.446 & 13.2 & *** \\ CI green & 30.693 & 7.828 & 0.432 & 13.3 & *** \\ NDVI & \(-\)40.481 & 120.412 & 0.281 & 15.0 & *** \\ WDRVI & 27.422 & 60.234 & 0.274 & 15.1 & *** \\ SR & 30.901 & 2.438 & 0.217 & 15.6 & *** \\ EVI2 & \(-\)30.779 & 228.633 & 0.203 & 15.8 & *** \\ EVI1 & \(-\)34.546 & 221.288 & 0.198 & 15.8 & *** \\ NDVI\({}_{705}\) & 10.544 & 116.844 & 0.185 & 16.0 & *** \\ SR\({}_{680}\) & 32.193 & 1.614 & 0.116 & 16.6 & *** \\ NDVI\({}_{680}\) & 40.587 & 30.073 & 0.006 & 17.6 & * \\ \hline \end{tabular} Notes: Statistical significance 0.05 “*”; 0.001 “***”.  
\end{table} 
Table 2: _Cont._  
Figure 5: Scatterplots of VIs that showed the highest correlation (\(R^{2}>0.53\)) with CC. Red: _R.__mangle_, black: _A.__germinans_, grey: _L.__racemosa_, and green: _C.__erectus_.