# Does Vegetation Recovery Limit the Habitat Use of Herbivore? Decadal Evidence of a Potential Ecological Mismatch

## TL;DR

Vegetation recovery in a reserve did not improve habitat for sika deer and may have caused an ecological mismatch over ten years.

## Contribution

Shows that forest restoration may not benefit herbivores due to ecological mismatch between vegetation and habitat use.

## Key findings

- Sika deer activity intensity increased significantly from 2015 to 2024.
- Vegetation indices had weak, negative effects on deer activity, while topographic and anthropogenic factors were significant.
- NDVI showed a significant increase before 2021 followed by a decline, indicating ecological mismatch.

## Abstract

In the context of large-scale forest ecological restoration, we examined the relationship between decadal (2015–2024) activity intensity of sika deer and vegetation (leaf area index and normalized difference vegetation index), together with topographic and anthropogenic factors. We found that activity intensity of sika deer had a sustained increase over time. Vegetation indices had weak, periodical effects on sika deer activity, whereas topographic and anthropogenic variables exhibited significant effects. Our findings demonstrate that vegetation recovery within the reserve does not automatically improve habitats for forest-dependent herbivores, and could lead to a potential ecological mismatch.

Large-scale forest ecological restoration is commonly expected to improve habitat quality and promote population growth of forest-dependent herbivores. Yet, whether vegetation recovery facilitates or constrains herbivore growth and habitat use at local scales within nature reserves remains unclear, as vegetation recovery and canopy closure might alter forage availability and lead to ecological mismatch between vegetation features and population dynamic. Here, we used the endangered species South China sika deer as the study species, and its dominant distribution region—Qingliangfeng Biosphere Reserve—as the study area. Using decadal camera-trapping data (2015–2024) and extracted vegetation and other environmental variables, we quantified decadal trends in sika deer activity intensity and interannual variation in vegetation (leaf area index, LAI, and normalized difference vegetation index, NDVI). We incorporated topographic and anthropogenic disturbance variables and applied generalized linear mixed models and generalized linear models to analyze its habitat use. We found that: (1) Numbers of independent photographs and the relative abundance index of sika deer increased significantly and consistently from 2015 to 2024. (2) LAI exhibited substantial interannual variability without a stable trend. In contrast, segmented regression identified a clear temporal breakpoint in NDVI, with a significant increasing trend before 2021 followed by a pronounced decline thereafter. (3) In all years, distance to settlement had a significant and negative effect on activity intensity, whereas distance to road, elevation, and year had significant positive effects. LAI and NDVI showed negative and weak effects on sika deer activity intensity. In specific years, LAI had a significantly negative effect in early periods whereas NDVI became significantly negative in mid and late periods. Other environmental variables exhibited interannual heterogeneity. Our findings demonstrate that vegetation recovery within the reserve does not automatically improve habitats for forest-dependent herbivores and could lead to a potential ecological mismatch.