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A number of recent studies have documented long-term declines in abundances of important arthropod groups, primarily in Europe and North America. These declines are generally attributed to habitat loss, but a recent study [B.C. Lister, A. Garcia,Proc. Natl. Acad. Sci. USA115, E10397–E10406 (2018)] from the Luquillo Experimental Forest (LEF) in Puerto Rico attributed declines to global warming. We analyze arthropod data from the LEF to evaluate long-term trends within the context of hurricane-induced disturbance, secondary succession, and temporal variation in temperature. Our analyses demonstrate that responses to hurricane-induced disturbance and ensuing succession were the primary factors that affected total canopy arthropod abundances on host trees, as well as walkingstick abundance on understory shrubs. Ambient and understory temperatures played secondary roles for particular arthropod species, but populations were just as likely to increase as they were to decrease in abundance with increasing temperature. The LEF is a hurricane-mediated system, with major hurricanes effecting changes in temperature that are larger than those induced thus far by global climate change. To persist, arthropods in the LEF must contend with the considerable variation in abiotic conditions associated with repeated, large-scale, and increasingly frequent pulse disturbances. Consequently, they are likely to be well-adapted to the effects of climate change, at least over the short term. Total abundance of canopy arthropods after Hurricane Maria has risen to levels comparable to the peak after Hurricane Hugo. Although the abundances of some taxa have declined over the 29-y period, others have increased, reflecting species turnover in response to disturbance and secondary succession.
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Understanding tropical forest abiotic response to hurricanes using experimental manipulations, field observations, and satellite data
Abstract. With projected increasing intensity of hurricanes and largeuncertainty in the path of forest recovery from hurricanes, studies areneeded to understand the fundamental response of forests to canopy openingand debris deposition: the response of the abiotic factors underneath thecanopy. Through two manipulative experiments and instrumenting prior toHurricane Maria (2017) in the Luquillo Experimental Forest (LEF) ofPuerto Rico, this study found a long recovery time of primary abioticfactors (beneath canopy light, throughfall, and temperature) influenced bythe disturbance of canopy opening, as well as complex responses by the secondaryabiotic factors (relative humidity, soil moisture, and leaf saturation)influenced by the disturbance of the primary factors. Recovery took 4–5 years for beneath canopy light, while throughfall recovery took 4–9 yearsand neither had recovered when Hurricane Maria passed 3 years after thesecond experiment. Air and soil temperature seemingly recovered quickly fromeach disturbance (<2.5 years in two experiments for ∼+1 ∘C of change); however, temperature was the most importantmodulator of secondary factors, which followed the long-term patterns of thethroughfall. While the soil remained wetter and relative humidity in the airstayed lower until recovery, leaves in the litter and canopy were wetter anddrier, with evidence that leaves dry out faster in low rainfall and saturatefaster in high rainfall after disturbance. Comparison of satellite and fielddata before and after the 2017 hurricanes showed the utility of satellitesin expanding the data coverage, but the muted response of the satellite datasuggests they measure dense forest as well as thin forest that is not asdisturbed by hurricanes. Thus, quick recovery times recorded by satellitesshould not be assumed representative of all the forest. Data recordsspanning the multiple manipulative experiments followed by HurricaneMaria in the LEF provide evidence that intermediate hurricane frequencyhas the most extreme abiotic response (with evidence on almost all abioticfactors tested) versus infrequent or frequent hurricanes.
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- Award ID(s):
- 1831952
- PAR ID:
- 10207117
- Date Published:
- Journal Name:
- Biogeosciences
- Volume:
- 17
- Issue:
- 12
- ISSN:
- 1726-4189
- Page Range / eLocation ID:
- 3149 to 3163
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.5194/bg-17-3149-2020
