Tropical mountain ecosystems: barometers of climate change?
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 The Chamela-Cuixmala Connection 180 160 140 120 100 80 60 40 Length of Dry Season 350 330 310 290 270 250 230 210 190 170 150 Length of Growing Season Length of dry season: positive trend Length of Growing Season: negative trend Sanchez-Azofeifa et al., In prep
9 8 Ecosystem Productivity 7 6 5 4 3 Species dominance and loss of Biodiversity Cactaceae Agavaceae
Are the trends valid worldwide? - Are there idiosyncrasies? A few important questions in need of urgent answers - Will tropical species respond in a similar way as temperate species? -Can we, rapidly enough, identify the first signs of climate change? - Are there reliable indicators for the phenomenon in the tropics?
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Foto: Miguel Andrade
Caatinga (Seasonaly Dry Tropical Forest)
Atlantic Rain Forest
Cerrado - Savanna
ESPINHAÇO MOSAIC THERMOMETER OF CLIMATE CHANGE IN THE TROPICS
Natural Experimental Design Those variables that most influence species biodiversity and distribution varies in a few kilometers
Conservation & Extinction Of the 538 plant species under threat in the State of Minas Gerais, 81 are from the Atlantic Rain Forest, 19 from the Seasonaly Dry Tropical Forests and 424 are from the Cerrado!
Conservation & Extinction Of the Cerrado, 67% (351 species) are from this mountain chain
Life on extremely poor soils (all quartizitic), under water stress and high UVB radiation has shaped a spetacular ecosystem, yet to be revealed to the international community
We are exploring biodiversity and the fine tuned interactions and adaptations among species and their environments in these mountains to gage climate change in the tropics Biodiversity Phenology Dynamics population & genetics Structure and composition Invasive species Physiology Mutualisms... Morphological convergences
IN THIS MOUNTAIN CHAIN SPECIES MAY BECOME INVASIVE AND SPREAD OUT Will they dominate the landscape and cause species loss? Baccharis dracunculifolia In open top CO2 chambers
Baccharis dracunculifolia BIOMASS, GROWTH, ARCHITECTURE, PHYSIOLOGY, NUTRITIONAL QUALITY, ANATOMY, ENDOPHYTES [CO 2 ] 360 ppm [CO 2 ] 720 ppm
Total Stem Baccharis dracunculifolia BIOMASS (mg) [CO 2 ] elevated, [CO 2 ] ambient Roots Leaf 157% 97% 152% 354 % 354% Time (days) ***P < 0.001
Height (cm) Baccharis dracunculifolia GROWTH [CO 2 ] ambient [CO 2 ] elevated Time (days) **P < 0.001
# Leaves/shoot Architecture of B. dracunculifolia No. Leaves, No. Shoots, etc A key factor that influence the component community associated organisms = biodiversity [CO 2 ] elevated [CO 2 ] ambient Time (days) ***P < 0.001
ENDOPHYTES: Unknown component of biodiversity with a major functional role +++ Tolerance to high temperature +++ Tolerance to water stress +++ Plant secondary chemistry (flavonoids and derivates) Endophytes in B. dracunculifolia > 130 species Species Richness in C02 enriched plants
Realized environmental niche Actual distribution
4 15% 55-89% 15-32% 70 89% 32-55%
1500 m a.s.l. 800 m a.s.l. 1100 m a.s.l. 1200 m a.s.l.
Phenology & Climate The Phenology Towers Sensors: Piranometer + PAR (Up, Down) Rain,Soil and Air Temperature and Humidity
Mountain environments are harsher but... have an inate capacity to imediately respond to environmental signals Soil water content drops to zero in the dry Season (September 2010)
The Phenology or Greeness of the Cerrado and two habitats in the rupestrian fields
Merging ideas... The importance of an unknown component of Biodiversity Positive relationship between the number of endophyte species with ratio leaf fresh weight/dry weight polyphenols/specific leaf weight Leaf Spectral Signature Index (SR 750/705 ) water content
- Would their dynamics and composition mediate forest phenology and productivity? - What about the accuracy of the readings in land use from space? -What else are they doing?
Herbivores, Decomposers, Pollinators, Amphibians, Birds, Invasive species, Soil Microrganims, Endophytes
Diversity of Mycoryzhae World = 217 spp. Brazil = 119 (55%) S. Cipó = 49 spp. (23% of the World, 41% of Brazil)
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Bauhinia brevipes HR PAR PRE PAT OTH SUR
This plant resistance mechanism (Hypersensitive reaction) is augmented when plants are under higher temperatures (> 25ºC) and UV B (280 a 320 nm) (Allan & Fluhr 1997) Otherwise, the host efficiency to elicit such reactions against the unbidden guest is drastically reduced under nutritional and water stresses, such as those found at the canopy level and at harsher environments (Király et al. 2005) Juliao, Fernandes & Venticinque Uakari 2005, Ribeiro & Basset 2007, Fernandes et al. 2009
1. Under high temperatures, low availability of water and nutrients, and high UV radiation the mechanisms of defense emplyed by plants become slow and weak 2. The colonization of this hostile environment is facilitated by the hability of galling herbivores to geneticaly and hormonaly manipulate their sclerophyllous hosts plants 3. Advantages are gained also because they are able to colonize habitats that impose physiological limitations to their natural enemies (competitors, predators and pathogens)
FOSSIL EVIDENCE Gall Richness increased when Earth experimented an increase in Temperature (of 3-5 C) during the Cenozoic (36-58 m.y.a) At the same time the Richness of unconceald herbivores decreased
CLIMATE SIGNALS In Climate Sensitive Areas
Impact of hailstorm across plant taxa: defoliation and green fall in a harsh mountain environment
Damage variation Architecture Growth form Leaf thickness/sclerophylly
Effects on the flora and component community Growth, architecture, physiology (photosynthesis), disease susceptibility, mutualism (endophytes).