Monday, 19 August 2013

Invertebrates


Tropical Rainforests are well known for their high diversity and extreme examples of invertebrate fauna. The Atlantic forest is no exception and many charismatic groups are well represented.

REGUA has many scientists studying particular groups such as odonata, lepidoptera, treehoopers and thorn bugs, arachnids and praying mantis. Some of the most impressive sights in the forest are the swarms of army ants (Eciton burchellii) that travel in colonies of 100,000 to 2 million and forage across the forest floor for prey. When a swarm is found all the large-medium sized invertebrates in the area can be easily observed climbing up branches or fleeing from their nests and holes. Even top predators such as spiders and scorpions are at risk from these swarms, that can overpower prey much larger than the single ant. This is the period when many of the "ant" specialist birds can be seen hunting not the ants but the insects caught out in the open fleeing from the ants.  I have come across several army ant swarms and always find a flurry of bird activity when I do.

Below is a selection of a few invertebrates from hundreds I have found in the reserve;

Golden orb web spider
 
Tarantula sp.  
Crab spider sp.

unidentified large beetle.

Stick insect sp.
 
Praying mantis sp.
Flatworm sp

Leaf-cutter ants
 
 


Some new mammals!

Some of the recent highlights include:

Walking the Schincaroel trail with a group one morning produced a fantastic view of a pair of lesser grison. They are associated with forest and wetlands and the habitat we saw them in was open secondary forest, adjacent to a fast-flowing stream. This may continue to be a good spot for seeing this species in the reserve, as there has not been any recent sightings around wetlands where they have previously been reported from.
Lesser grison (Galictis cuja)
 
I have also had 3 separate sightings of nine-banded armadillos. The first on the start of the green trail just past the researcher's house at dusk, and two around the yellow trail at night. They are particularly shy of light, but appear to be less bothered by noise and you can creep very close to them if you switch off the torch. The start of the brown trail is another good spot where I have regularly heard them foraging at night.
Nine-banded armadillo (Dasypus novemcinctus)
 
I had been setting some traps along fast flowing streams in the higher areas of the forest as this is the favoured habitat of Water opossum and Scaly-footed (South American) water rat. I did not find any evidence of the opossums but did catch a Scaly-footed water rat on the stream at the start of the Schincaroel trail.
Scaly-footed (South American) water rat (Nectomys squamipes)
 
I have also had numerous sightings of Southern opossum and I have used my photos to identify individuals. There appear to be 5 in the immediate area around the lodge and start of the yellow and brown trails.
Southern opossum (Didelphis marsupialis)
 

Brown howler monkey (Alouatta guariba)
 
 
 

Almost a puma.

A few weeks ago another volunteer and I spent the night in the hide on the 4x4 trail in the hope of seeing the juvenile puma that has been frequenting the area. Although we did not see we it we did come very close.
I had previously put a dead chicken from the local shop in front of the "scent marking tree" the cat regularly uses to try and increase our chances of success. This proved to be very successful as I finally got footage of it on my camera trap.

video


The night we camped on the trail I did the same and for many hours we sat in darkness listening to the sounds of tawny-browed owls and frogs and watched the displays of fireflies.

 As much as I wanted to stay awake to see if anything came I could not stay alert all night and eventually we both fell asleep. However at about 4am I awoke to the sound of purring, and soon released that it was coming from the forest just to the left of us. Both of us stayed awake for a further 4 hours listening intensely to the sound, I heard a few grunts and on occasion a heavy breath. The sound became very clear and close (maybe 10 meters) on several occasions and it was apparent it was moving around the hide. It could surely smell us inside the hide and the dead chicken nearby and was wisely suspicious. It never did show itself, but listening to recordings on the internet I am 90% sure that it was the juvenile puma. It just goes to show how intelligent and secretive these cats are even at an early age. We only rarely heard a twig snap and it was almost impossible to detect him moving at night.

Friday, 16 August 2013

Amphibians at REGUA

Brazil has the highest diversity of frogs and toads in the world, (likely more than 760 species occur) and the Atlantic forest is very important to this group as maybe 40% of the frogs and toads living here are endemic.

The wetlands at REGUA are an important breeding and calling site for many species and many different species can be heard calling from the water and islands at night. The other place to look is in bromeliads as many small tree frog species use these for breeding and calling. There is a particularly high abundance of bromeliads in the Atlantic forest and they can be found growing on many host trees particularly in higher altitudes.


Some of the species I have seen and identified include:

Burmeister's leaf frog (Phyllomedusa burmeisteri)

Two spotted tree frog (Dendropsophus bipunctatus)

Bandeirantes snouted tree frog (Scinax perpusillus)

Haddadus binotatus
 
Cane toad (Rhinella icterica)
 
Creole frog (Leptodactylus latrans)

Hylodes lateristrigatus
 
 
Dendropsophus elegans

Teresopolis tree frog (Aplastodiscus arildae)

Porto Alegre golden-eyed tree frog
 (Trachycephalus mesophaeus)
 
 
 

Gunther's smooth horned frog (Proceratophrys appendiculata)
 
Ischnocnema guentheria
 
I am still working on the identification of many species which I have only seen in their juvenile state which makes them extremely hard to identify.