Table 1 Explaining diverse empirical patterns on the local-regional diversity change and changes in the fraction of unique species caused by habitat destruction (or climate change) using the general framework proposed in the present study.
From: A general framework for predicting delayed responses of ecological communities to habitat loss
Possible empirical patterns | Possible explanations using the proposed framework | |
|---|---|---|
Local diversity versus regional diversity change | ||
1. | Local diversity increases; Regional diversity increases | Immigration credit occurs across all the spatial scales. This can happen when SAAD is shifted from aggregation to randomness and habitat destruction is low (Fig. 3A,B). |
2. | Local diversity increases; Regional diversity decreases | Immigration credit occurs at local communities with small area sizes, while extinction debt occurs for the whole remaining region. This may happen when SAD is fixed to be lognormal, while SAAD is allowed to shift from aggregation to randomness and when habitat destruction is high (Fig. 3A). |
3. | Local diversity decreases; Regional diversity decreases | Extinction debt occurs at all spatial scales. This may happen when (1) both SAD and SAAD are fixed before and after habitat loss (Fig. 2A,B) or (2) when SAD is fixed, while SAAD is shifted from randomness to aggregation (Fig. 3A,B). |
Changes in the fraction of unique species | ||
1. | Fraction of unique species increases after habitat loss | This may occur (1) when the sum of area sizes of a pair of local communities is large enough and when SAAD is shifted from randomness to aggregation, while SAD is fixed (Fig. 3G,H) or (2) both SAD and SAAD are fixed in logseries model (Fig. 2H). |
2. | Fraction of unique species decreases after habitat loss | This may occur (1) when both SAD and SAAD are fixed in lognormal model (Fig. 2G) or (2) when SAAD is shifted from aggregation to randomness, while SAD is fixed (Fig. 3G,H). |
3. | No fraction of unique species change after habitat loss | This may occur when species distribution is highly aggregate, regardless of SAD models used (Supplementary Figs. S1G,H). |
Alpha diversity versus change in the fraction of unique species | ||
1. | Local alpha diversity increases; fraction of unique species increases | This may occur when species distribution pattern is extremely aggregated in lognormal model (Fig, S1A versus S1G). |
2. | Local alpha diversity increases; fraction of unique species decreases | This may occur when SAD is fixed, while SAAD is shifted from aggregation to randomness (Fig. 3A versus 3G or 3B versus 3H). |
3. | Local alpha diversity decreases; fraction of unique species decreases | This may occur when both SAD and SAAD are fixed (Fig. 2A versus 2G or 2B versus 2H). |
4. | Local alpha diversity decreases; fraction of unique species increases | This may occur when SAAD is shifted from randomness to aggregation (Fig. 3A versus 3G or 3B versus 3H). |
