An Assessment of the Vulnerability of Eastern Pygmy Possums to Climate Change Exacerbated Drought in the Ku-ring-gai Area

Author: Bob I Jones (Independent Volunteer Citizen Science Researcher for my project “Eastern Pygmy Possum Program and Recovery Plan for Ku-ring-gai Municipality” with OEH and NPWS and Volunteer former Volunteer Coordinator of the WildThings NSW Pygmy Possum Project in collaboration with KMC staff)

Date: 04 June 2019               ACADEMIA.EDU:  https://mq.academia.edu/bobijones 

Over many years of bushwalking in the lovely bushland reserves and National Parks of the Ku-ring-gai area, I have noticed unmistakable changes in the floristic composition and structure of the vegetation along

 

Banksia Death

Rainfall Sufficiency Zones

Figure n: modified from figure 22 page 18 of Leeper, G.W., CSIRO The Australian Environment (Fourth Edition), 1970. Shows the length of the growing period in months during which rainfall was calculated as effective. The red zone within the 5-9 period in Queensland represents climates where the five months of effective rainfall are not consecutive.

Rainfall Requirements of Banksias

Figure n: from Wikipedia article on Banksias shows the distribution of Banksias in Australia.

Note that Banksias grow only in the zones of effective rainfall where there are consecutive months of effective rainfall forming a growing season (i.e. low enough monthly variability)

Pygmy Possum (Cercartetus spp shown) Distribution

 

Honey Possum Distribution

 

 

Northern Glider Distribution

 

This Drought

Monthly rainfall for St Ives (Richmond Avenue), Ku-ring-gai Wildflower Garden: Red bold indicates years with less than 5 consecutive months of sufficient rainfall, months with insufficient rainfall of less than 50% of the mean rainfall for the month, and highly deficient annual totals below 1000 mm.

Year

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Total

2014

25.4

78.8

179.6

76.2

19.6

55.8

14.6

263.3

68.0

66.2

18.8

174.6

1040.9

2015

172.4

45.6

55.2

363.2

104.4

75.4

39.0

36.0

83.2

27.6

87.8

100.8

1190.6

2016

357.2

23.2

111.4

38.4

12.8

339.8

99.0

132.2

58.1

38.8

29.4

70.2

1252.4

2017

33.2

189.2

391.0

47.2

22.0

179.4

2.6

28.6

0.8

51.4

42.0

56.4

1043.8

2018

35.6

118.8

128.6

20.0

25.6

112.6

5.4

5.2

48.8

271.2

133.8

87.8

993.4

2019

69.6

82.2

259.8

33.8

32.6

118.8

 

 

 

 

 

 

 

Mean

106.8

140.4

151.4

108.2

89.1

137.2

63.8

80.6

45.2

86.2

97.6

88.8

1195.3

Table n: the totals above where extracted from the BOM annual rainfall statistics for KWFG as collected by rangers specifically Jenny Edejones

 

Note that none of the past years of the Pygmy Possum Project (2014 to 2018) has had sufficient rainfall with 2018 being overall highly deficient in rainfall. Only the most recent September 2018 to March 2019 period had sufficient rainfall, i.e. 7 months of sufficient rain. However, the past 2 months have again been deficient despite a near coastal location where rainfall is at its most reliable. As you move west rainfall deficiency worsens leading to the rapid drop in dam levels that lead to current water restrictions.

 

Role of Climate Change

Migration of Climate Zones South

Impacts on Pygmy Possum Abundance and Distribution

1 Reproduction Rates

2017 Nest Box 1: 4 Juveniles in litter with 1 Adult Female

2017 Nest Box 7: 2 Juveniles in litter with 1 Adult Female

2017 Nest Box 22: 4 Juveniles in litter with 1 Adult Female

Video from camera placed to record activity indicates that up to 4 juveniles of assorted sizes were in the nest box with the mother

2018 Nest Box 6: 1 Juvenile in litter with 1 Adult Female

 

2 Fox “Holes”

3 Hazard Reduction Burns

4 MTB Tracks

5 Ingress of Displaced Predator – Red Fox

Other Indicators of Climate Change

I have been searching for possible Eastern Pygmy Possum (EPP) Cercartetus nanus habitat in the Ku-ring-gai Municipality since 1 December 2013. Following on from Dr Brad Law’s lecture the previous day, I walked from West Pymble to South Turramurra along the Lane Cove Valley to check out occurrences of the EPP food plant heath-leaved banksia Banksia ericifolia (BE).

Of the 28 nest box deployments the host species was:

Seasonal Variations in Nest Box Occupation

By number of observed occupations by pygmy possums:

Number of observed occupations by pygmy possums

Nest Box Program Phases

 

 

 

Number of observed juvenile pygmy possums

 

 

 


Year

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

2013

 

 

 

 

 

 

0

0

0

0

0

0

2014

0

0

0

0

0

0

0

0

0

0

0

0

2015

0

0

0

0

0

0

0

0

0

0

0

0

2016

0

3

3

0

0

0

0

0

0

0

0

0

2017

0

0

0

4

2

6

4

0

0

0

0

0

2018

0

0

0

0

1

1

 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pilot Upper Lane Cove Valley at Canoon Road area

 

Complete Upper Lane Cove Valley Program and Start Cowan Catchment Program

 

Break in program – nest boxes left in place

 

Build Cowan Catchment Program and Middle Harbour Catchment Program

 

Hand over Program to KMC using Fulcrum app

 

Year

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

2013

 

 

 

 

 

 

0

0

0

0

0

0

2014

0

0

0

0

1

0

0

0

0

1

0

0

2015

0

0

0

0

0

0

0

0

0

0

0

0

2016

1

2

0

0

0

0

0

0

0

0

0

0

2017

0

0

0

4

1

6

5

3

0

0

0

1

2018

0

0

0

0

1

1

 

 

 

 

 

 

 

Possible Determining Factors influencing Nest Box Occupation

Possible Trends in Abundance:

Fluctuation in Nest Box Occupation from year to year

Fluctuations in Number of Nights taken to Detect Pygmy Possum occurrence with Wildlife Cameras

Results

Many nest boxes were occupied by EPP females and their offspring shortly after the start of the Banksia ericifolia flowering season in mid-March with 4 of the 6 nest boxes deployed to known pygmy possum habitat for 18 months having pygmy possums in them when monitored and the other 2 having definite indications that pygmy possums did occupy them at some stage. Shortly before the end of the Banksia ericifolia flowering season in mid-September the pygmy possum families had moved on. In October it was found that pygmy possums were feeding on Callistemon citrinus blooms in wetter areas of Coastal Upland Swamp characterized by Gahnia sieberiana adjacent to the Banksia ericifolia containing areas where the nest boxes were deployed, but not on Callicoma serratiolia blooms in the adjacent gully areas. This may indicate horizontal rather than vertical migration of pygmy possums to chase flowering food sources.

 

EPPs were found at

Map

 

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