The Editor’s Choice article for Volume 107 Issue 6 is a study by Quintana‐Ascencio et al., which looks at the role of seed dormancy, dispersal and fire history on plant population dynamics, distribution and abundance. Associate Editor, Shurong Zhou, discusses this new research paper in more detail.
Biodiversity conservation and management depend on our understanding of population dynamics at multiple scales. However, most population models consider only small spatial scales. The predicted patterns of distribution and abundance may not scale up to a larger, regional scales – where environmental or anthropogenic changes are usually involved (Beissinger & Westphal 1998). So, predicting regional population distribution and viability may be critically important when dealing with large scale changes in population dynamics, for conversation and management. However, possibly due to difficulties in collecting long-term and large-scale demographic data, many studies chose to ignore the underlying landscape issue or treat it in a simplistic manner.
This study takes advantage of a long term and well replicated data set (15 populations, 11 K individuals, 38 K unique annual observations during 22 years) that combines detailed demography collected at small scales with spatially explicit drivers of demography including patch size, patch isolation, fire history, and relative elevation. The inclusion of variables at the landscape level and the evaluation of 340 various rates of seed dormancy and seed dispersal resulted in substantial improvement of their integral projection model in projecting observed occurrence and presence of H. cumulicola.
The authors found that the best model had limited dispersal and considerable seed dormancy, which matched the characteristics of the plant species associated with observed occurrences (67% correct) and densities (20% of variance explained). Burn synchrony among neighboring patches (skewness in the number of patches burned by year = 1.79) probably explains the higher densities predicted by the simulation with the historical fire regime compared with predicted abundances after simulations using random ignition years (skewness = 0.20 + SE = 0.01). The habitat of this species experiences spatial and temporal changes in suitability associated with time-since-fire. Large open gaps in recently burned Florida rosemary scrub patches are the most suitable habitat for H. cumulicola (Quintana- Ascencio et al. 1998, Quintana-Ascencio et al. 2018). Selection for dormancy and post-fire germination increases the chances that seeds are able to take advantage of the occurrence of more suitable, recently burned habitats. Seed dispersal allows seeds to reach neighboring habitats that are suitable.
In summary, this paper draws on many areas of ecology to produce interesting and predictive models that give us insights into basic biology, management and conservation. At the landscape scale, decisions on prescribed fires will benefit from the knowledge of the consequences of fire frequency, the location of ignitions and the probability of fire spread. This article also noticed the significance of changing availability and configuration of suitable habitats, associated with human or non-human landscape changes. This study demonstrated that using landscape level drivers and spatial patterns of distribution to infer life history traits could be used in many other systems.
Shurong Zhou, Associate Editor, Journal of Ecology
Read the full article online: “Assessing the roles of seed bank, seed dispersal and historical disturbances for metapopulation persistence of a pyrogenic herb” by Quintana‐Ascencio et al. (2019)
Find out what else features in Volume 107, Issue 6 of Journal of Ecology here: https://jecologyblog.com/2019/10/17/volume-107-issue-6/