ACA researcher concerned about dramatic decline in rainforest frogs

ACA researcher concerned about dramatic decline in rainforest frogsFor two decades now, Alessandro Catenazzi, Ph.D., an assistant professor of zoology at Southern Illinois University, Carbondale, has been using the ACA biological stations in the Peruvian rainforest to learn more about the frog population in the region.

Catenazzi and his colleagues have made several important discoveries that increase our understanding about amphibian diversity and threats, and help inform conservation priorities. One of these is that highland creek frogs are declining dramatically due to chytrid, a fungus considered the most significant threat to the world’s amphibian populations. “I have memories of working there in the 1990’s and just walking along these creeks, and there were all these frogs calling and the pools were full of tadpoles,” he said during a recent interview with ACA. ACA researcher concerned about dramatic decline in rainforest frogs Andrew Catenazzi“Now the creeks are dead zones.” 

Another discovery found that lowland frog populations show little tolerance for climate change, where an increase of only two degrees Celsius could be problematic for their survival. Recent temperature trends recorded by Catenazzi and his team are alarming. “So far this year, temperatures in the rainforest have been off the charts,” Catenazzi noted. “And when you look at mathematical models predicting temperatures that the rainforest is expected to experience in the years ahead, the future for lowland rainforest frogs appears to be very bleak.” These findings provide still another reason why nations need to slow global warming, he stressed.

Through his many years studying the frog population in the Andes-Amazon, Catenazzi has given the scientific community and the public at large a greater understanding about the issues facing frog populations. For more information about Catenazzi’s research, visit his blog at: http://www.catenazzilab.org/  

MAAP #34: New Dams on The Madeira River in Brazil Cause Forest Flooding

The Amazon lowlands have been connected to the Andes Mountains for millions of years by only six major rivers: the Caqueta, Madeira, Maranon, Napo, Putumayo, and Ucayali* (see Image 34a). This intimate connection allows rich Andean nutrients to fuel the Amazon floodplain and enables long-distance catfish migration between feeding grounds in the lowlands and spawning grounds in the highlands.

Image 34a. Data: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo
Image 34a. Data: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo

However, one of these six major Andean tributaries has recently been dammed on its main channel: the Madeira River in western Brazil (See Inset A). The Santo Antônio dam was completed in 2011, followed by the upstream Jirau dam in 2013.

Note in Image 34a that these dams are are located downstream of the Madre de Dios River in southern Peru. Thus, major ecological impacts — such as blocking the route of migratory catfish**— are also very relevant to Peru.

Here in MAAP #34, we describe the forest loss—over 36,100 hectares—associated with the flooding caused by these two dams (with a focus on the Jirau dam).


Zoom A: Forest Loss due to Flooding

Image 34b shows the forest loss due to flooding immediately upstream of the Jirau dam. As of 2015, the total flooded area for both dams is 36,139 hectares (89,301 acres). Major flooding was first detected in 2010, rose substantially in 2011-12, and peaked in 2014.

According to Fearnside 2014, although much of the forest along the Madeira is seasonally flooded, it dies when permanently flooded.*** Therefore, the flooded area is an appropriate measure of forest loss.

Further below, we show a series of satellite images of the areas indicated by Inset B (see Images 34c-e) and Inset C (see Image 34f).

Image 34b. Flooding-related forest loss along the Upper Madeira River. Data: USGS, CLASlite, Hansen/UMD/Google/USGS/NASA.
Image 34b. Flooding-related forest loss along the Upper Madeira River. Data: USGS, CLASlite, Hansen/UMD/Google/USGS/NASA.

Zoom B: Flooding Immediately Upstream Jirau Dam

Image 34c shows the flooding immediately upstream of the Jirau dam between 2011 (left panel) and 2015 (right panel). The red dot is a point of reference that indicates the same place in both images. Below, we show high-resolution images of the areas indicated by Insets B1 and B2.

Image 34c shows the flooding immediately upstream of the Jirau dam between 2011(left panel) and 2015 (right panel).
Image 34c shows the flooding immediately upstream of the Jirau dam between 2011(left panel) and 2015 (right panel).

Zooms B1 and B2: Jirau Dam and Flooding

Image 34d shows a high-resolution view of the Jirau dam in July 2015. Image 34e shows a high-resolution view of a portion of the flooded area immediately upstream of the Jirau dam in August 2015. The red dot is a point of reference that indicates the same place in both panels.

Image 34d. High-resolution view of the Jirau dam. Data: WorldView-2 from Digital Globe (NextView).
Image 34d. High-resolution view of the Jirau dam. Data: WorldView-2 from Digital Globe (NextView).

Image 34e: High-resolution view of flooded area immediately upstream of the Jirau dam. Data: WorldView-2 from Digital Globe (NextView).
Image 34e: High-resolution view of flooded area immediately upstream of the Jirau dam. Data: WorldView-2 from Digital Globe (NextView).

Zoom C: Flooding Further Upstream of Jirau Dam

Image 34f shows the flooding further upstream of the Jirau dam between 2011 (left panel) and 2015 (right panel). The red dot is a point of reference that indicates the same point in both images.

Image 34e: High-resolution view of flooded area immediately upstream of the Jirau dam. Data: WorldView-2 from Digital Globe (NextView).
Image 34e: High-resolution view of flooded area immediately upstream of the Jirau dam. Data: WorldView-2 from Digital Globe (NextView).

References

*Finer M, Jenkins CN (2012) Proliferation of Hydroelectric Dams in the Andean Amazon and Implications for Andes-Amazon Connectivity. PLOS ONE: 7(4): e35126. Link: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0035126

**Duponchelle F et al (2016) Trans-Amazonian natal homing in giant catfish. J. Appl. Ecol. http://doi.org/bd45

***Fearnside PM (2014) Impacts of Brazil’s Madeira River dams: Unlearned lessons for hydroelectric development in Amazonia. Environmental Science & Policy 38: 164-172.


Citation

Finer M, Olexy T (2015) New Dams on the Madeira River (Brazil) Cause Forest Flooding. MAAP: 34.

MAAP #33: Illegal Gold Mining Alters Course of Malinowski River (Border of Tambopata National Reserve)

In MAAP #30, we described the illegal gold mining invasion of Tambopata National Reserve, an important protected area in the southern Peruvian Amazon (department of Madre de Dios). Here in MAAP #33, we show that illegal gold mining is also altering the course of the Malinowski River, which forms the natural boundary of the Reserve. Image 33a shows the two areas where we have documented a total artificial deviation (cutting) of 4.4 km (2.7 miles) of the river (see details below).

Image 33a. Data: Planet Labs, SERNANP
Image 33a. Data: Planet Labs, SERNANP

Zoom A: A Recent Deviation of the Malinowski River

Image 33b shows the final stage of the deviation of the Malinowski River between March 31 (left panel) and May 3 (right panel) of this year in the area indicated by Inset A in Image 33a. The new flow of the river is clearly seen in the right panel, cutting a 1.7 km stretch of the previous course.

Image 33b. Data: Planet Labs, Digital Globe (Nextview)
Image 33b. Data: Planet Labs, Digital Globe (Nextview)

Image 33c shows with greater precision how the Malinowski river was diverted in this area between April and May 2016. The red arrow indicates the exact same place across time in the three images.

Image 33c. Data: Digital Globe (Nextview)
Image 33c. Data: Digital Globe (Nextview)

Zoom B: An Earlier Deviation of the Malinowski River

In February 2016, Peruvian specialists presented how mining activity had recently changed the natural course of the Malinowski river in the area indicated in Inset B*. Image 33d shows the progressive change: from the increase in mining activity along the normal course of the river in June 2013 (left panel), to the new stretch of riverbed in June 2015 (center panel), and finally to the expansion of mining activity along the previous course (right panel). The red dot indicates the same place over time in the three images. A total of 2.7 km was cut from the previous river course.

Image 33d. Data: Digital Globe (Nextview), Planet Labs
Image 33d. Data: Digital Globe (Nextview), Planet Labs

Ecological Impacts

According to Dr. Carlos Cañas**, coordinator of the Amazon Waters Initiative for Wildlife Conservation Society in Peru, the deviation of the natural course of the Malinowski River will have significant ecological impacts, including:

  • Although the Malinowski River’s course has natural movement, the changes documented in MAAP #33 definitely represent an artificial alteration caused by mining activity.
  • These artificial changes are altering the course of the Malinowski from one that is “narrow and defined” to one that is “wide and scattered.” This change impacts the river’s flood patterns by changing the intensity, timing, and frequency of flooding along the river’s banks. This implies an effect on the migratory behavior of many species of fish downstream, which receive and interpret signals from the river to guide vital functions like feeding and reproduction.
  • The river’s new wider course also causes the velocity of water downstream to decrease, which will lead to increased levels of sediment in the discharge zone of the largest tributary, the Tambopata. Given the nature of the Tambopata, this could provide the almost-permanent damming of the Malinowski, as greater volume of the Tambopata means more sedimentation at the mouth of the river. Among other things, this could hinder the entry of fish to their feeding zones.
  • As seen in Image 33d, fish access to certain areas will be interrupted by the blockade and closure of channels. Also, the connection between the floodable forest and the river channel is completely altered, if not interrupted, in this section of the river. Many fish species that eat fruit or vegetation from the adjacent forest depend on this seasonal connection for food.
  • The Malinowski River, since it is a tributary of the Tambopata River, has natural areas that are crucial to the reproduction of many local species. Its tributary streams represent habitats that differ from the main river and harbor an incredible variety of fish and invertebrates that contribute to the biodiversity of the river basin. These streams have little sediment, and are thus highly transparent. Mining will destroy or drastically alter these environments, severely impacting this biodiversity.

Referencias

*Villa L., Campos L. G., Pino I. M. (01 de febrero de 2016). Primer Sistema de Alerta Temprana de Geoinformación (SAT-GI) para Áreas Naturales Protegidas del Perú: Reserva Nacional Tambopata y el Ámbito de Madre de Dios del Parque Nacional Bahuaja Sonene. Reporte Nº 001-2016.

** Cañas CM, Waylen PR (2011) Modelling production of migratory catfish larvae (Pimelodidae) on the basis of regional hydroclimatology features of the Madre de Dios Basin in southeastern Peru. Hydrol. Process. DOI: 10.1002/hyp.8192.

**Cañas CM, Pine WE (2011) DOCUMENTATION OF THE TEMPORAL AND SPATIAL PATTERNS OF PIMELODIDAE CATFISH SPAWNING AND LARVAE DISPERSION IN THE MADRE DE DIOS RIVER
(PERU): INSIGHTS FOR CONSERVATION IN THE ANDEAN-AMAZON HEADWATERS. River Res. Applic. 27: 602–611.


Citation

Finer M, Novoa S (2016)  Illegal Gold Mining Alters the Course of the Malinowski River (border of Tambopata National Reserve). MAAP: 33.