A 40-year evaluation of drivers of African rainforest change
Por:
Chapman, Colin A., Galan-Acedo, Carmen, Gogarten, Jan F., Hou, Rong, Lawes, Michael J., Omeja, Patrick A., Sarkar, Dipto, Sugiyama, Anna, Kalbitzer, Urs
Publicada:
9 oct 2021
Resumen:
Background Tropical forests are repositories of much of the world's
biodiversity and are critical for mitigation of climate change. Yet, the
drivers of forest dynamics are poorly understood. This is in large part
due to the lack of long-term data on forest change and changes in
drivers. Methodology We quantify changes in tree abundance, diversity,
and stand structure along transects first enumerated in 1978 and
resampled 2019 in Kibale National Park, Uganda. We tested five
predictions. First, based on the purported role of seed dispersal and
herbivory and our quantification of changes in the abundance of
frugivores and herbivores, we tested two predictions of how faunal
change could have influenced forest composition. Second, based on an
evaluation of life history strategies, we tested two predictions
concerning how the forest could have changed following disturbance that
happened prior to written history. Finally, based on a 50-year climate
record, we evaluate the possible influence of climate change on forest
dynamics. Results More trees were present on the assessed transects in
2019 (508) than in 1978 (436), species richness remained similar, but
diversity declined as the number of dominant species increased. Rainfall
increased by only 3 mm over the 50 years but this had not significant
effect on forest changes measured here. Annual average monthly maximum
temperature increased significantly by 1.05 degrees C over 50 years. The
abundance of frugivorous and folivorous primates and elephants increased
over the 50 years of monitoring. Neither the prediction that an increase
in abundance of seed dispersing frugivores increases the abundance of
their preferred fruiting tree species, nor that as an increase in
folivore abundance causes a decline in their preferred species were
supported. As predicted, light-demanding species decreased in abundance
while shade-tolerant species increased as expected from Kibale being
disturbed prior to historical records. Finally, while temperature
increased over the 50 years, we found no means to predict a priori how
individual species would respond. Conclusions Our study revealed subtle
changes in the tree community over 40 years, sizable increases in
primate numbers, a substantial increase in the elephant population and
an increase in local temperature. Yet, a clear picture of what set of
interactions impact the change in the tree community remains elusive.
Our data on tree life-history strategies and frugivore/herbivore
foraging preferences suggest that trees species are under opposing
pressures.
Filiaciones:
George Washington Univ, Dept Anthropol, Ctr Adv Study Human Paleobiol, Washington, DC 20037 USA
Wilson Ctr, 1300 Penn Ave NW, Washington, DC 20004 USA
Univ KwaZulu Natal, Sch Life Sci, Pietermaritzburg, South Africa
Northwest Univ, Shaanxi Key Lab Anim Conservat, Xian, Peoples R China
Univ Nacl Autonoma Mexico, Escuela Nacl Estudios Super, Morelia, Michoacan, Mexico
Robert Koch Inst, Viral Evolut & Epidemiol Highly Pathogenom Microo, Seestr 10, D-13353 Berlin, Germany
Univ Malaysia Sarawak, Inst Biodivers & Environm Conservat IBEC, Sarawak 94300, Malaysia
Makerere Univ Biol Field Stn, Ft Portal, Uganda
Carleton Univ, Dept Geog & Environm Studies, Ottawa, ON, Canada
Univ Hawai Manoa, ScH Life Sci, Harold L Lyon Arboretum, 3190 Maile Way, Honolulu, HI 96822 USA
Max Planck Inst Anim Behav, Dept Ecol Anim Soc, Radolfzell am Bodensee, Germany
Univ Konstanz, Dept Biol, Constance, Germany
Green Submitted, gold, All Open Access, Gold
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