Natural disasters and the science of landscape connectivity

Climate change is predicted to increase the number and severity of storms and other large-scale disturbances.  What does this mean for maintaining a well-connected landscape, and how will connectivity be altered by extreme weather?  Recent studies give us clues into the aftereffects of hurricanes, floods, and other natural disasters, and how ecosystems might respond to these events depending on their connectivity.

Natural disasters

    • Antarctica may not be as biologically isolated as previously believed.  Genetic analysis of rafting keystone kelps shows that they traveled over 20,000 km to reach Antarctica, and that this is probably a common occurrence assisted by strong storms.  Surface waves and ocean eddies that result from storms such as cyclones and anticyclones greatly enhance ocean connectivity and contribute to greater dispersal of new species into the region.
    • Plant diversity is at its highest in floodplain forests that are large, well-connected, and flood frequently.  A comparison of vegetation surveys from the 1950’s to current conditions across 40 floodplain forests in Wisconsin shows patterns of increasing local diversity coupled with declines in community distinctiveness.  Frequent flooding is known to increase connectivity of riparian forests and aid water-dispersed species.
    • Riparian habitats support a high amount of invasive species, with river corridors acting as efficient dispersal highways.  The invasive Himalayan balsam plant (Impatiens glandulifera) is twice as likely to be found in river patches of central Europe that are subjected to flooding as compared to those that aren’t.  Flooding acts as a main factor for invasion by spreading seeds, increasing nutrients in the water, and disturbing native plants.
    • Community response to disturbance can be influenced by numerous factors, including disturbance intensity, time, initial species richness, and isolation. A global dataset from both aquatic and terrestrial ecosystems shows that connected communities are significantly more similar to control communities post-disturbance than isolated communities.  This holds true for a wide range of disturbances, including hurricanes, flooding, overgrazing, and experimental disturbances.
    • Tropical dry forests are highly resilient to extreme disturbances such as hurricanes, floods, and droughts.  In Mexico, these forests’ resilience is dependent on precipitation regime, with recovery more difficult after extremely dry years.  The unpredictable nature of tropical dry forest response at the ecosystem, landscape, community, and population levels means that management decisions post-disturbance may be challenging.

 

Resources

Álvarez-Yépiz JC and Martínez-Yrízar A (Eds). 2018. Special Issue: Resilience of tropical dry forests to extreme disturbance events. Forest Ecology and Management 426:1-176.

Čuda J, Rumlerová Z, Brůna J, Skálová H, and Pyšek P. 2017. Floods affect the abundance of invasive Impatiens glandulifera and its spread from river corridors. Diversity and Distributions 23: 342-354.

Fraser CI, Morrison AK, Hogg AM, Macaya EC, van Sebille E, Ryan PG, Padovan A, Jack C, Valdivia N, and Waters JM. 2018. Antarctica’s ecological isolation will be broken by storm-driven dispersal and warming. Nature Climate Change 8: 704-708.

Johnson SE, Amatangelo KL, Townsend PA, and Waller DM. 2016. Large, connected floodplain forests prone to flooding best sustain plant diversity. Ecology 97: 3019-3030.

Shackelford N, Starzomski BM, Banning NC, Battaglia LL, Becker A, Bellingham PJ, Bestelmeyer B, Catford JA, Dwyer JM, Dynesius M, Gilmour J, Hallett LM, Hobbs RJ, Price J, Sasaki T, Tanner EVJ, and Standish RJ. 2017. Isolation predicts compositional change after discrete disturbances in a global meta‐study. Ecography 40:1256-66.

2018-09-19T16:01:38+00:00 September 14th, 2018|

About the Author:

Heather Cayton
Heather Cayton is the Managing Director of ConservationCorridor.org and a Research Assistant at Michigan State University. She received her B.S. from the University of Virginia and her M.S. from Virginia Tech, and has spent the past nine years studying corridors and rare butterflies in North Carolina.