# Relating Habitat Suitability and Survival Rates in a Phylogenetic Framework

## TL;DR

This study explores how habitat suitability models compare to actual survival rates of non-native maple species in the UK, using a phylogenetic framework to understand ecological performance.

## Contribution

The study introduces a phylogenetic framework to explain discrepancies between habitat suitability models and observed survival rates in ex-situ species.

## Key findings

- High niche overlap with native species did not always correlate with high survival rates.
- A. pictum showed high survival despite low niche overlap, suggesting phylogenetic relationships influence ecological performance.
- The study reveals a phylogenetic signal in survival patterns, indicating conserved traits may be masked in traditional models.

## Abstract

Species distribution models rely on species' observed geographic distributions, which reflect only subset of the true ecological niche. This inevitably leads to discrepancies between the predictions of habitat suitability (HS) and the actual ecological performance in novel environments beyond the trained range. We examined this limitation by comparing modelled HS with empirical survival rates (SRs) of three Acer species, A. davidii, A
.
palmatum
, and
A. pictum
, cultivated in the UK botanic gardens. We hypothesise that ex‐situ species with greater niche overlap with native UK/European species will show higher HS, which also correspond to species' SR relative to that of local species. This HS‐SR alignment will then indicate the alignment of species' geographic range and ecological range. We first quantified niche similarity between these East Asian species and UK/Europe native Acer species at both regional and continental scales. MaxEnt models were calibrated using native occurrences with various combinations of environmental variables and model configurations, then projected onto UK regions. Species' SRs were standardised against those of native species using long‐term inventory data. Our results show that niche overlap with native species generally corresponded to predicted HS, while observed SR patterns revealed an inverse relationship. A. davidii, showing high niche overlap and high HS, exhibited the lowest SR. Contrarily,
A. pictum
, despite showing low niche overlap and predicting most regions unsuitable, demonstrated the highest SR, comparable to native species. This discrepancy was particularly noteworthy as
A. pictum
shared closer phylogenetic relationships with European species, while A. davidii was more closely related to North American species. The observed phylogenetic signal in SR patterns suggests that intrinsic traits that relate to climate tolerance may be conserved yet masked in the conventional modelling approach. This interdisciplinary approach bridges the gap between macro‐scale predictions and local‐scale individual performance, offering a new perspective on niche conservatism through a phylogenetic framework.

We investigated the relationship between ecological niche similarity and habitat suitability (HS) and between HS and standardised survival rates (SSRs) on the selected ex‐situ Acer species, A. davidii,
A. palmatum
, and
A. pictum
, in the UK. We also aimed to explain these relationships in a phylogenetic framework. We hypothesised that species with high niche similarities to native UK species will exhibit high HS, which in turn will correlate with high SR.