The Grange Reserve report PDF

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Produce a brief research report summarizing the findings of our surveys investigating post fire growth, reproduction at The Grange Reserve, and implications for fire management....

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The Grange Reserve Quantitative Monitoring Research Report

Dayanna Añazco University of Melbourne 21/ 10/2018

The Grange Reserve Quantitative Monitoring Research Report Dayanna Anazco University of Melbourne Parkville VIC 3010

Acknowledgements University of Melbourne: School of BioSciences Vegetation Management and Conservation (BOTA30004_2018_SM2) subject Lecturers and coordinators Acacia oxycedrus surveying team colleague’s contribution

Summary: Vegetation surveys were conducted at 6 ecologically burned sites at The Grange reserve, using the Quadrats quantitative method. The surveys focused on six different Australian native species. Acacia oxycedrus, Acacia paradoxa, Bossiaea cinerea, Ricinocarpos pinifolius, Olearia ramulosa. To examine the relationship between growing stages, abundance and reproduction post fire and its implications for fire management. This report summarises the method used to collect the data for the six species. Furthermore, it focuses on the sp. Acacia oxycedrus (EVD 2), analysing the growth stage persistence, by calculating variables such as time since fire, density and height. The initial hypothesis was to prove that if younger specimens are growing in the most recently burned sites, these will be smaller in height and volume than the mature individuals growing in the site burned in 1991. The importance to test this assumption is to prove how effective is the reproductive response in relation to the time since-fire. As a result, the trend data for all the species matches the planted hypothesis. However, as (Cheal 2010) states, each vegetation community passes through different growth stages at a different rate. This is why in the case of Acacia oxycedrus, even though the overall results match with the hypothesis, there are slight inconsistencies with the expected size in site 2008 which presents smaller individuals than in 2015. Several reasons can explain this inconsistency, such as mean annual rainfall, soil moisture and fertility, or the intensity of the fire at the time of the burning. Also, it can mean errors at the moment of data recollection. Key words: EVD2, quantitative Analysis, Post fire growth stages, Acacia oxycedrus.

Introduction: Fire shapes ecosystems’ composition, richness and organism’s distribution and adaptations. Fire also affects the soil chemistry composition such as PH, moisture and nutrients that influences plant growth and reproduction. Australia’s pyrogenic flora depends of different degrees on fire, at different fire regimes, to germinate and develop (Enright & Goldblum 1999). These factors have inspired the use of fire in planning and policy for ecological regeneration. In Victoria, the rationale for fire management approach is presented in the Guidelines and procedures for ecological Burning on public land (which has been tested and improved since 1999). It informs about the scientific basis, vital attributes, and tolerable fire intervals to spatially explicit native vegetation, describing habitat parameters for each growth stage through time since fire (Cheal 2010; Muir et al. 2014). This report uses the Growth stages and TFI for Victoria’s native vegetation data sets, to classify the EVC for the surveyed species grouped into (EVD) ‘ecological vegetation divisions’ to infer the fire response characteristics according to their respective ‘ecological fire group’ (EFG). Therefore, Acacia oxycedrus belongs to the EVC 6 Sand Heathland (City of Kingston, 2018). Which according to (DELWP) belongs to EVD 2 Heathland (sands). Thanks to this classification it can inferred (see table 1- EVD 2 Description) that in the surveyed burned sites, the growth stages renewal, juvenility, adolescence and maturity will be found, corresponding with the time since burning (Cheal 2010). Renewal and juvenility (in 2016 site, 2y since burning), Juvenility and Adolescence stage in sites (2015 & 2012, 3-6y since fire), and a mature stage in sites (2008, 2003 10-15y since fire). Considering that adolescent and mature specimens are bigger in size and volume (VicFlora 2016). The following hypothesis was stablished, if younger specimens are growing in the most recently burned sites, these will be smaller in height and volume than the mature individuals growing in the site burned in 2003. To test this hypothesis not only qualitative methods, such as observation were used. Also, the quadrats survey method was utilized to gather numeric data about the size and abundance of the Acacia oxycedrus. Also, the survey has different objectives like analyse the effectiveness of fire as regeneration method and test how the fire tolerance intervals and growth stage attributes collected on field match with the theory of EVD growing stages. Table 1: Description of EVD 2, Ecological features and fire behaviour

Site description and location: The reserve was once part of the Bunurong people territories, thus it’s also part of aboriginal heritage. Today the Grange has an area of 7.0 ha approx. The topography of the site consists on sand dunes with slopes that extend from the eastern side down to the east. The site also suffers seasonal inundation and is composed by open sandy soils, with high drainage capacity. Method: The area designed to survey was analysed before going to the field, by observing a map of the burned sites. In addition, five groups of approximately six people were chosen to focus on six native species. Acacia Oxycedrus, Acacia paradoxa, Bossiaea cinerea, Ricinocarpos pinifolius, Olearia ramulosa. The prime objective of the field trip was to survey 6 burned sites (1991, 2003, 2008, 2012, 2015 and 2016). To quantify the measures of the different species the quadrats surveying method was used. Prior to the establishment of the quadrats, on the day of the fieldtrip a site recognition was realized. During this recognition each group focused on their respective species to observe and recognize potential abundance and size. Also, to identify the location of the different burned sites. Quantitative data collection for Acacia oxycedrus Size and Abundance -The order of the sites to analyse was selected by proximity. -The first burned site analysed was 2016 site, which has an area of 157 m2. Here five quadrats of 50cmx50cm where measured randomly. Secondly, the team headed to the 2015 site, which has an area of 736 m2. Here 2 quadrats of 2mx5m were placed. The same quadrat measurements and quantity were placed in sites 2003, 2012, and 2008. These sites have areas of 868 m2, 185m2 and 2502 m2, respectively. -Once the quadrats are stablished, Acacia oxycedrus specimens are spotted by observation. Since the areas are small is possible to count each individual inside every quadrat. It is important to mention that we counted any individual that had more than 50% of its base inside the quadrat. -After counting, five random individuals are selected to measure their height, canopy width and length. Acacia oxycedrus is a multi-stemmed specie therefore the height was measured from the base up to the top of the longest branch. -To record the measurements, we used abundance and size recording tables (See appendix 1). -Finally, every team entered the data collected on a shared google doc. (See the doc here). The results were calculated and plotted using the R-studio program.

Quantitative data collection summary for Acacia paradoxa, Bossiaea cinereal, Ricinocarpos pinifolius and Olearia ramulosa.

Refer here for the complete summary of methods and quantitative data document.

Results: Acacia oxycedrus

Size H (cm)

The data analysed was modelled in the form of box plots to understand the relationship between growth stages and time since fire. These plots enable comparisons between the data collected on the field and the assumed results according to EVD 2 theory of growth stages. The variables considered where, density of specimens per square meter, the height of specimens since time of fire, and the volume of canopy per sample analysed in the burn year.

Burn Year

The Size – burn year plot shows the following relationship: - The height of the sampled individuals decreases in the recently burned sites. In the 2016 site, the maximum height is 76cm while in the site burned in 2003, the maximum height is 150 cm approximately. - Even though 2003 site was the oldest site surveyed the tallest specimens where found in site 2015, with a maximum height of 162 cm. - There is a lack of data in the year 1991 which is the oldest site analysed by the rest of the groups in The Grange reserve.

Canopy Volume (m)

Density (number of individuals/ m2)

Burn Year

Burn Year

These plots enabled comparisons between the density of the Acacia oxycedrus and the time since fire, and the canopy volume found in each burn site. - There is an increasing density which means more individuals per m2 where found in the sites burned in 2015 and 2008. However, the data plots cero density for the year 2016, this means almost no individuals were found in this site. This data can be compared with appendix 1 and appendix2, which shows that only 4 individuals where found in site 2016. - Whereas the number of individuals increase the volume of these, decreases dramatically in sites 2016 and 2015. - The box plot for volume shows a spike of high-volume individuals in site 2008, this means 10 years since burn.

Acacia paradoxa, Bossiaea cinereal, Ricinocarpos pinifolius and Olearia ramulosa relationship between height (m) and time (years) since fire.

-The overall results for the 5 species, displayed similar patterns of decreasing height for the most recently burned sites.

-There is a lack of data for Acacia paradoxa -There is also a trend shared by all the species, 2015 seems to be a burned site with the tallest individuals. With the exception of Ricinocarpus pinifolius, and Acacia paradoxa. -This plot also shows Acacia oxycedrus data for the 1991 burn site. However, this site was not surveyed on the day of the fieldtrip. Therefore, errors entering the data have been made. This though, does not impact the data for the rest of the burned sites. Discussion: Acacia oxycedrus has been classified within the EVD 2 (Cheal 2010). The data collected, and results reveal patterns of growth stage persistence, by calculating the variables time since fire, density height and canopy volume. The theory suggests that for an (EVD2) Sandy Heathlands the older specimens (post-fire 1991), are expected to be in juvenile and mature stages. Whereas the younger specimens (post fire 2016), are assumed to be transitioning from renewal stage to juvenile growth stage (Muir et al. 2014). At the same time younger specimens are smaller in size than mature specimens (Broadhurst et al. 2008). Therefore, if younger specimens are growing in the most recently burned sites, these will be smaller in height and volume than the mature individuals. The relationship, size-burn year meets the stated hypothesis. There is a decreasing size of individuals in site, 2016. But the hypothesis also suggests that the year 2015 which is only 3 years since fire, should present smaller specimens compared with the oldest site surveyed, 2008. Nonetheless, the tallest Acacia oxycedrus were found in 2015 site, with heights up to 162 cm. Broadhurst 2008, suggests that changes in the soil as well as climatic factors can be the reason for the variations in heights. It is important to consider, that dry periods just passed in the months on June and July and the soil of The Grange consists mainly on sands, which explains high drainage and less soil moisture retention. Less water means, slow chemical reactions which activates nutrient function in the soil. The heights found in 2015 however, are still small to medium (VicFlora 2016), and it is not inconsistent with the expected growth stage because, as stated by (Cheal 2010), Juvenile individuals develop in the first 2,5-8,5 years after fire and this stage is characterized by rapid shoot extension and flowering resprouters. Therefore, individuals under the 3 meters height are within the normal height for a juvenile Acacia oxycedrus. The density per square meter also supports the Theory of EVD 2 growth stages. First of all, Acacia oxycedrus is an obligate seeder, which means it takes longer to germinate than other species, therefore is normal to find almost no individuals in a site burned just 2 years ago. The decreasing volume of individuals in recently burned sites also supports the expected hypothesis. As one of the objectives this report was focused on analysing the effectiveness of fire as regeneration method, which can be supported by the evidence found. Burned sites germinate naturally, restoring the Acacia oxycedrus community as observed in the increasing density per m2 in site 2015. Furthermore, after testing the fire tolerance intervals and growth stage theory corresponding to EVD 2, it can be stated that the use as of EVD as management planning tool is correct and should be continued to be developed. Also, there were limitations in this research, such as short amount of time to realize the quadrats surveying and errors at the moment of entering the data of the Google document.

Acknowledgements: We thank specially the Subject lecturer and coordinator David Duncan for conducting the R-studio program workshop, and for providing on field guidelines, as well as theoretical guidance.

References

Broadhurst, L. M., Lowe, A., Coates, D. J., Cunningham, S. A., McDonald, M., Vesk, P. A., & Yates, C. (2008). Seed supply for broad scale restoration: maximizing evolutionary potential. EVOLUTIONARY APPLICATIONS, (4), 587. Retrieved from City of Kingston (2018) Grange Heathland Reserve, Clayton South: Flora, Fauna. Retrieved from: Demography of a non-sprouting and resprouting Hakea species (Proteaceae) in fire-prone Eucalyptus woodlands of southeastern Australia in relation to stand age, drought and disease. (1999). Plant Ecology, (1). Retrieved from

Ecological Vegetation Domain (EVD) lookup (2018): Department of Environment Land Water and Planning (DELWP). Retrieved from:

Growth stages and tolerable fire intervals for Victoria’s native vegetation data sets. (2010). Melbourne: Victorian Government Department of Sustainability and Environment, c2010. Retrieved from

Messina A. (2016) Royal Botanic Gardens Victoria, VicFlora: Acacia oxycedrus. Retrieved from: Muir, A. M., Vesk, P. A., & Hepworth, G. (2014). Reproductive trajectories over decadal time-spans after fire for eight obligate-seeder shrub species in south-eastern Australia. AUSTRALIAN JOURNAL OF BOTANY, (5), 369. Retrieved from

Appendix Appendix 1

Appendix 2...