A Cycad Calamity?

One of the forms of analysis that I am interested in is GIS, Geographic Information Systems, specifically using ARCmap. Thus I was pleased when the Threatened Species Unit asked for my help in analysing data for a cycad (Cycas brunnea) population in Boodjamulla National Park. The plants populations were assessed due to a significant wild fire which swept through the area in September 2011. A. Freeman collected the data in 2010 and 2012 in order to assess the status if the population after the fire. Below is the report, compiled with two of the maps I created. The remainder of the report was composed by A. Freeman.

This publication is not for redistribution. 

Petaurus australis: Yellow-bellied Gliders

Yellow-bellied glider (Petaurus australis) feeding on the sap of Eucalyptus resinifera in Tamoulin Forest, Atherton tablelands, QLD (McCaffrey M, 2012)

Introduction:

(Gilmore S, 2012)

Some of the most interesting creatures I saw whilst in Queensland were the gliders; feather-tail, sugar and yellow-bellied. These mammals have found unique ways to combat the harsh environmental conditions of Tropical North Queensland; active at night they avoid the heat of the day and drinking the sap of Eucalyptus resinifera trees overcomes the seasonal food shortages (Smith, 1982 p.149). The yellow-bellied gliders (YBG) status is vulnerable (Commonwealth Environment Protection and Biodiversity Conservation Act 1999 and State Nature Conservation Act). This is due to habitat disruption (mostly owing to land clearing and altered fire regimes), their populations are isolated and the gliders have a very specific habitat - a thin band of wet sclerophyll (Goldingay, R Possingham H 1995 p. 162).

Wet Sclerophyll forest; E.resinifera in Gilby forest, Atherton tablelands, QLD. (Gilmore S, 2012) 

A Description of Wet Sclerophyll: 
Hard leaves, short internodes (the interval from leaf to leaf along the stem), rainfall above 1100mm a year and mostly between 600 and 1300m above sea level. The forests have deep leaf litter, fleshy-fruited plants and very large trees (Gullan, n.d.).

Eucalyptus grandis; hollow, broken off branches are used as dens by the YBGs. (Gilmore S, 2012)

Potential Habitat compared with YBG sightings

There are three major subpopulations, as seen in the two maps below (from North to South):

• Mt Windsor tableland,
• Mt Carbine Tableland and
• The Cardwell Range.

Map 1 shows the area in which the YBGs could potentially inhabit and sightings of the animal in TNQ follow the pattern in Map 2. The three subpopulations (as seen in Map 2) are separated by unsuitable habitat - for not only do they prefer the wet schlerophyll forest but much of the area around the patches are dominated by humans. This restriction of habitat limits their already low populations.

Map 1: Potential YBG (Wet Tropics) habitat distribution (Queensland Government, 2010).

Map 2: YBG known distribution (Queensland Government, 2010)

Methods:

Spotlighting:
Determining where the YBGs are is key to streamlining the surveying process. If we can determine the general area in which they are found we are more likely to locate their feed trees. We arrived at known feed trees before sunset to catch a glimpse of the gliders and a number of groups, such as the Tableland National Park Volunteers, spend a few evenings a month looking for their eye shine.

Feed tree surveys:
Yellow-bellied gliders have specially shaped teeth to be able to break through the tough bark of Eucalyptus resinifera (feed trees) and they leave obvious signs as to their presence, however the cuts remain for years after. It is essential to age the cuts if we are to discover whether the gliders are present and/or active in the area:

Yellow-bellied gliders have teeth designed specifically for breaking through thick bark to tap into the sugar rich sap of trees such as E. resinifera (Lindenmayer D, 2002).

E. resinifera with the 'lady-lip' shaped cuts of the YBG; notice the redness of the trunk due to the sap from active cuts running down the bark- an active tree such as this stands out starkly in the forest.(Gilmore S, 2012)

By ageing the cuts we can infer how active the tree is (Tableland National Park Volunteers, 2012):

Active cuts:

1a: Wet furry edges – a very recent, fresh cut exuding dark sap with animals (birds, insects) seen feeding at the cut (photo courtesy of J.Winter).

1b: Dry furry edges - no sap oozing from wound nor animals feeding at it. (Gilmore S,  2012) 

Inactive cuts

2: Fresh kino present (Kino being the hard red substance sealing the wound) (Gilmore S,  2012) .

3: New pink, unweathered scar tissue (Gilmore S,  2012)  

4:Weathered scar tissue (Gilmore S,  2012)  

Observation suggests that a stage 1a cut may progress to a stage 2 cut after a few weeks. Stage three cuts may be months old and stage 4 cuts are usually at least a year old (pers. comm Winter J., November 2012). Using the age of cuts we can then map their activity and learn more about their behaviour, needs and threats.

Mapping the habitat: 
Data is steadily being collected of the two trees critical for the YBGs: E. resinifera (feed trees) and E. grandis (den trees) so that we may map the distribution of their potential habitat.

Map 3: Mapping YBG habitat; recording feed (inactive as well as active) and den trees (Courtesy of Winter J)

Threats:

There are several threats facing the YBG’s, the largest being how the changes in fire regime have altered vegetation structure. An introduced weed, lantana, is one of the problems caused by this change - the tangled vines of the plant pile up in the understory and without a good burn the weed begins to chew up the amount of space the gliders may soar through.

Lantana (Lantana camara), besides being exhaustingly difficult to break a path through, it readily grows into thickets, invading the understory of the forest (Gilmore S, 2012).

Battling through Lantana in high temperatures made field surveys a slow gruelling process (Gilmore S, 2012). 

Then, of course, with human dominated surrounds comes clearing and fragmentation of habitat - cutting off glider populations, removing essential trees and reducing the amount of resources available (space, food etc). Grazing and barbed wire fencing have a minor impact but adds salt to an already open wound. Lastly, climate change has unknown consequences for the YBGs; however with a very specific habitat and food regime any significant change in temperature could have disastrous consequences for the YBGs.

An old E.grandis stands exposed in Gilby forest after volunteers cleared a fire break to protect the valuable den tree from fire (Gilmore S, 2012).  

Action plan for 2013:

(Queensland Government, 2010)

This is a brief overview of an action plan created by John Winter with the Queensland Government. The objective is to minimise the impact of threats on the Wet Tropic YBG populations and to protect as well as recover the known populations. It also includes plans to engage the community, employ adaptive fire management and use resources effectively. A comprehensive plan such as this requires time, money and manpower; all of which are in short supply. However there is a group of passionate, environmentally aware individuals on the Tablelands that are willing to donate time and elbow grease to the cause; The Tableland National Park Volunteers (TNPV).

Tableland National Park Volunteers: 

From 2010 the TNPVs have been running the YBG surveys led by volunteer wildlife ecologist Dr John Winter. The project not only gathers valuable data but inspires the community to be more engaged in local issues and gives them a chance to make a difference. They cover a wide range of issues and activities, one of which being the data collection and protection of the YBGs. I was lucky enough to be involved in a few of their projects for the short time I was there and it has inspired me to look into a wider range of environmental action when in New Zealand. Without these volunteers there would be many an issue that would go unexplored and a variety of research, management and education left in hiatus.

Tableland National Park Volunteers: Volunteers from a variety of backgrounds take a break whilst looking for new Feed Trees (Gilmore S, 2012).

TNPV: Recording YBG activity on a known Feed Tree (Gilmore S, 2012).

TNPV and the School for Field Studies joining forces to monitor weed around Lake Eacham,  Atherton Tablelands (Gilmore S, 2012). 

Potential future research:


My involvement with the Wet Tropics Yellow-bellied glider (Petaurus australis) project demonstrated the obvious knowledge gaps that would affect how the species is managed. Their conservation status is vulnerable and according to one of those most involved in the projects “It faces a high risk of extinction in the wild in the medium-term future.” (A. Winlaw, pers. comm, 2012). The Yellow-bellied gliders' habitat is disrupted and the populations are isolated. They are threatened by changes in fire regime, by clearing and fragmentation of habitat and a number of other variables as yet not understood. My study will focus on why they feed on particular trees and what the patterns mean. The yellow-bellied gliders have specially designed teeth allowing them to break through the hard bark of Eucalyptus resinifera (feed trees) to access the sugar rich sap. This research would involve established techniques such as: 

• Camera traps 
• Forest and fauna surveys 
• Spotlighting
• Faecal analysis and direct observation to determine diet 
• Chemical analyses of the sugar content of the sap 

The gliders seem to abruptly arrive and leave different feed trees with little cause, I would like to learn why they feed off certain trees and ignore others. I would look at a number of variables, the most obvious being sugar content of different feed trees but I will also look at defence mechanisms within the trees and the diet of the gliders. I’m sure as the project develops further the number of variables I will want to consider will expand. This project will require data collection in the field in Tropical North Queensland, however I will write the thesis at Lincoln University, New Zealand.

References

Goldingay R, Possingham H 1995. 'Area requirements for viable populations of the Australian gliding marsupial Petaurus australis', Biological Conservation, vol. 73, Issue 2, pp. 161–167. Retrieved February 24th 2013 from http://www.jstor.org/stable/4316?seq=1. 

Lindenmayer, D.B. 2002. Gliders of Australia. A natural history. University of NSW Press, Sydney.

Paul Gullan, n.d.,Wet Sclerophyll Forest. Retrieved March 03, 2013 from, http://www.viridans.com/ECOVEG/wet%20sclerophyll.htm).

Smith A.P 1982. 'Diet and Feeding Strategies of the Marsupial Sugar Glider in Temperate Australia', British Ecological Society, vol 51., no. 1, pp. 149-166.

Tableland National Park Volunteers 2012. 'Yellow-bellied Glider: Sap Feed Trees'. Unpublished reference guide.  

Queensland Goverment, QLD 2010, National recovery plan for the yellow-bellied glider (Wet Tropics) Petaurus australis unnamed subspecies

An introduction

Australia has always been a place I had to explore one day; the hot roasted plains, the weirdly wonderful creatures, the charming laid back lingo of the locals. Thus when I was offered a place in the Master of International Nature Conservation programme (Lincoln University, NZ) I knew exactly where my required internship would take place. With the help of an Aussie at Lincoln University I was introduced to Alastair Freeman in the Threatened Species Unit (TSU) of Environment and Heritage Protection (EHP) of Queensland Parks and Wildlife Services (QPWS). 

From September 17th to December 7th I worked within QPWS. My main supervisor was Alastair Freeman - the last remaining member of the TSU of the Atherton Tablelands. The main projects I was involved in with Alastair were surveys and monitoring of the Johnstone river snapper (Elseya irwini). Alastair then helped me get involved with several other projects, much of this through two people: 
Jodie Eden: 
Volunteer coordinator of the Atherton Tablelands. My main involvement with Jodie was pest control and management, as well as threatened species surveys and monitoring. 

An exhausted team of volunteers after weeding for Coffea arabica  at Lake Barrine, Atherton Tablelands. 

Keith MacDonald:
TSU of the Atherton Tablelands. The activities with Keith centered around threatened plants surveys and collection.

Voucher collection of Denrobium johannis in Riniyurru National Park with K. MacDonald

I have been very lucky in the opportunities provided for me here; I was dragged up to Cape York and towed around the Tablelands with eyes wide at every passing new landscape and species. I have participated in monitoring programs for turtles, weed management, yellow bellied gliders, quolls and threatened plants. Then there have been surveys, habitat mapping and literature reviews. However, surprisingly enough, I feel I learned the most from the people that sit around the coffee table in the office or the campfire in the field. Rangers, resource managers, coordinators and researchers; all of these people have a fantastic insight into the inner workings of conservation in Queensland. I found that there is division in opinion over how much should be burnt and that although the public feels feeding cassowaries is a good idea it really is not in the species best interest. It has been interesting learning about the different laws and acts in Queensland and how people react to them as they filter down to their level. Those in the Atherton office, and in the parks I have visited, have welcomed me and have graciously answered the many questions I have thrown at them. I hope that within this internship I was half as useful and helpful to the people here as they have been to me. 

Elseya irwini (Johnstone river turtle) Monitoring and Surveys.

This is an ongoing monitoring project of high altitude populations (above 700m) of Elseya irwini. The turtles have been subjected to several taxonomic name changes over the past few years, traveling from Elseya dentata to Elseya strilingi to arrive at Elseya irwini. Little was known about the E. irwini population on the Atherton Tablelands and this project aims  to determine the current threats to the population in the hope that this will inform future management plans. E. irwini’s conservation status was recently listed as “high priority”, thus making the importance of having baseline data all the more significant. In other words, the more we know about how they operate now the better we can recognise changes and deal with the effects.

Surveys:

Surveys have been conducted throughout the Atherton Tablelands in search for the presence of E. irwini. This involved snorkeling through rivers in the catchment area catching turtles by hand  whilst recording time; allowing us to calculate CPUE (catch per unit effort). Any turtles caught were examined and released within a few minutes. The CPUE measurement gives us an idea on how dense the populations of E. irwini are in an area. If a lot of turtles are caught in a short period of the time we might conclude the population to be dense and vice versa. Surveys give us an idea as to the areas in which the species occur.

Monitoring:

For these monitoring sessions we have 4 locations, ideally visited twice a year between September and November (dependant on river conditions). Permission from landowners is required to access the riverside and most landowners have developed an active interest in the project. There are two individuals searching, in most cases, whilst timed to determine CPUE. We have one hour in which to catch as many turtles as able. Part of the monitoring process is making use of mark and recapture: before the E. irwini turtles are returned to the water they are marked and tagged so they may be identified if recaptured. This method allows us to estimate the size of the animal’s population. 

Once caught there are several aspects of the turtles we are interested in:

Measurements:

Measured to the nearest millimeter using vernier calipers:

• Straight carapace length and width.
• Straight plastron length and width.
• Tail to carapace edge.

Measured to the nearest gram using a digital balance:

• Weight.

Straight carapace length of a female 

at the Allwood's monitoring site:

Tail to carapace edge of a male 

at the Allwood's monitoring site:

Weight:

Damage: 

The turtles were examined for damage upon capture. Individual turtles were divided into the three categories seen in Table 1 as per the damage assessment. Most turtles suffered little damage, the worst in 2012 being a missing foot (however whether the turtle had been born thusly or had somehow  lost it was unclear). The damage assessment is yet one other factor which helps determine the health of a population. 

Small female from Fanning's 

monitoring site with  a missing foot:

Table 1. Definitions of broad damage categories allocated to each turtle (Freeman 2011 p.7)

Sexing:

Turtles were identified as either female or male by comparing the ratio of tail to carapace edge length. If the tail to carapace length was too small to measure the turtle was classed as a juvenile. Males have a significantly longer tail to carapace edge length than females (Fig 1).

 Figure 1. Ratio of Straight Carapace Length (SCL) to Tail Length (TL) for male, female and juvenile Johnstone River snappers captured during the monitoring seasons 2008, 2009 and 2011 and including incidental records from 2008 and 2010, excluding recaptures (n=205). (Freeman 2011 p.6) 

Juvenile:

Female:

Male:

 A note regarding Elseya latisternum: 

 There is a second species of turtle found on the Atherton Tablelands (and through much of Queensland) Elseya latisternum – the saw-shelled turtle. As the turtles are caught by hand it is difficult to avoid catching the saw-shells when under water thus data is being collected on them on the side. We take the same measurements but when caught E. latisternum are merely marked and not tagged as they are a secondary interest and tags are expensive.

Why do we want this data?

These measurements help us compare:

• The populations between monitoring sites
• The differences between genders and ages.
• Marking the turtles helps us follow population trends: births, deaths, immigration and emigration. 

The findings thus far: 

Despite habitat modification the population is healthy:

• There is a wide range of age cohorts. Populations that are under stress or in decline tend to have a skewed age distribution (either positive or negative) i.e. a larger number of younger or older turtles. However, this means we must continue to monitor the turtle populations as areas of their habitat continues to be developed. (Freeman 2011 p. 13). 
• Also, There has been little sign of damage to the animals captured.

The sex ratio has differed over the monitoring years. In other words the number of males to females has not remained constant it has changed from year to year. The study has yet to clarify the status of the species in the Atherton tablelands as it is still in progress.

Potential threats: 

Feral animals are one of the biggest threats to nesting sites. In 2010 nests at the ‘Allwood's’ monitoring site were recorded. Predation occurred 3-6 days after oviposition; all known nests were predated and all known eggs destroyed (Freeman 2011). At this time A.Freeman (2011) set up camera traps and snapped a picture of a long-nosed bandicoot and giant white-tailed rat interfering with a turtles nest on the bank of the Johnstone River (Fig 2). Both quite capable of excavating a nest and been recorded eating the eggs of E. irwini (O’Malley, 2007).

Fig 2 Two burglars caught interfering with a turtles nest by a camera trap at the Allwood's monitoring site.

Removal of riparian vegetation might affect the turtles adversely and may already be doing so. Vegetable matter (fruits, leaves and so on) falling from riparian vegetation is a significant source of food for these web-footed herbivores. An interesting further study would be to determine what effect its removal may have on the turtles. Also, is run off affecting the populations?

It is hoped that the monitoring will continue into the medium-term future but of course it all depends on funding and whether those higher up on the ladder see the projects importance.

With issues such as predation, land development and potential 

climate change; what is the future for Elseya irwini?

References:

Freeman, A.B. and Curran, T. 2009. Johnstone River Snapper (Elseya stirlingi) on the Atherton Tablelands, summary report for the 2008 monitoring season.Unpublished report to Department of Environment and Resource Management, Atherton. 16p.

Freeman, A.B. and Curran,T. 2010. Johnstone River snapper (Elseya stirlingi) on the Atherton Tablelands, summary report for the 2009 monitoring season.Unpublished report prepared for Department of Environment and Resource Management, Atherton. 12pp.

Freeman, A.B. 2011. Johnstone River snapper (Elseya irwini) on the Atherton Tablelands, summary report for the 2010 monitoring season.Unpublished report prepared for Department of Environment and Resource Management, Atherton. 17pp.

O’Malley, A.J. 2007. The ecology of Elseya stirlingi from the Johnstone River system

of North Queensland. Unpublished Thesis, James Cook University, Townsville. 127pp.