| Survey/Project Number: | 1174 Total No. of Sites: 0 |
| Survey/Project Name: | APY LANDS BUFFEL GRASS PHD- does invasion impact plant/animals in an arid system |
| Abstract: | Full project name is 'Does Buffel Grass (Cenchrus ciliaris) invasion impact plant-animal interactions in an arid system?' This is a PhD research project with Charles Darwin University (CDU, Alice Springs campus) in partnership with APY Land Management and APY Organisation. The research is to be conducted on the Anangu Pitjantjatjara Yankunytjatjara (APY) Lands in the north west of South Australia between 2018 and 2021. The research aims to firstly assess the changes to plant and animal communities and important plant-animal interactions in response to the invasion of a highly invasive and declared weed, buffel grass across large areas of the APY Lands. The first component will look at changes over an approximate 25-year timeframe, by resurveying sites where historical biological survey data was collected prior to buffel grass becoming a major problem. Floristic, vegetation structure and fauna data will be collected to enable comparisons between invaded and univaded sites, and over time, to confirm whether certain plant or fauna guilds are more susceptible to change and whether there is a shift from woodlands to grasslands with fire-accelerated buffel grass invasion. In addition, the PhD research will focus on the interaction between seeds and seed-eating animals (granivores) which is a key plant-animal interaction expected to change. This research will track seed production, granivorous ant foraging and diet, and the experimental removal of seeds by vertebrates in invaded and natural habitats to analyse the impacts of buffel grass invasion on granivory. A third focus for the PhD research will aim to record information during hunting expeditions for maku (edible root-dwelling larave: witchetty grubs) in invaded and uninvaded habitats in order to document the impacts of buffel grass invasion on the abundance and accessibility of maku, as a model for the cultural impacts of invasion as maku is a highly important bushfood and keystone cultural resource for A?angu people. Research Aims Research Component 1: Assessing ecosystem change with buffel grass invasion over an approximately 25-year period through multi-taxa biological survey 1. What changes have occurred in plant and animal communities with buffel grass invasion and can changes in specific fauna guilds and plant groups be identified? 2. Is there evidence of a decline in abundance of trees and shrubs in invaded areas, and an overall shift from woodlands to grasslands, and how does this relate fire? Research Component 2:. Investigating a key plant-animal interaction predicted to be affected by under-storey change: Granivory, the interaction between seed resources and seed consumers 3. How is the availability of seed resources throughout the year in the under-storey altered by buffel grass invasion? 4. How do granivorous ants adapt to altered food resources in buffel grass invaded landscapes and what consequences are there for plants or ants? 5. Does buffel grass invasion reorganise the vertebrate granivore community and their contribution to seed removal? Research Component 3: Investigating a key plant-animal interaction predicted to be affected by over-storey change: The availability of maku (root-dwelling larvae: witchetty grubs) as a model for impacts on Anangu culture and ecosystems services 6. Is the abundance and accessibility of a key bushfood (maku) reduced by buffel grass invasion and is this related to ecological processes (e.g. reduced abundance of host plants) or cultural impacts (e.g. perceptions of hunting in buffel grass)? |
| Start Date: | 14/09/2018 End Date: 30/06/2021 |
| Survey Type: | Vegetation and Fauna |
| Study Area Description: | APY Lands - defined as the local government area of Anangu Pitjantjatjara Yankunytjatjara (APY) |
| Objectives | |||
| Vegetation: | Refer to Abstract. | ||
| Fauna: | Refer to Abstract. | ||
| Methodology | |||
| Vegetation: | Methdology Component 1: Multi-taxa Biological Surveys Past biological survey data, including presence and abundance of plant species, birds, mammals and reptiles, is available from the 1990s APY Lands biological survey, and we will repeat surveys at these sites and at new spatially paired sites to detect any changes in presence or abundance of plants and animals at invaded sites compared to sites remaining free from buffel grass. Surveys will be undertaken in 2018 in the western APY Lands and 2019 in the eastern APY Lands, including 28 sites for birds and vegetation and 12 sites for small mammal and reptiles. Methods used at each site follows that recommended for biological surveys in South Australia (Heard and Channon 1997, Owens 2000) and includes some additional methods. Bir. Vegetation will be sampled in one-hectare vegetation quadrats including species composition, cover abundance, life form, life stage and vegetation structural paramters including overstory measuremnts of 10 individual overstorey trees/shrubs per site (if present). Physical site parameters will be recorded incluing soil type, landform and other attributes. Additional methods will include the use of drone imagery to map the size of the buffel grass invaded patch around the site, the use of different imagery types (satellite, aerial photos, old vertical photopoints and drone imagery) to map the change in tree/shrub denisty since the 1990s survey, and record the fire history of each site. Methdology Component 2: Plant-granivore interactions 4 invaded and 4 uninvaded one-hectare sites will be used to all track seed resources, to study ant foraging and diet and to identify vertebrate seed removers. Sites will be spread out in an approximate 20km radius from the community of Umuwa, APY Lands, in order to account for the larger home ranges of some vertebrate seed-removing animals, but still within easy driving access. Seed resources: Seed production will be examined four times per year in the eight one-hectare sites for 2 years. All understory plants will be recorded in nested quadrats of increasing size (0.25m squared to 16m squared) to determine frequency and rarity values, which can be converted to species abundance and density (Morrison et al 1995). Plant phenology will be recorded on each visit, and seed production will be estimated when understorey plants are seeding for a select number of species including buffel grass. The number of spikes (infructescences) per plant will be counted for maximum 100 individuals (and maximum 20 per site). Four spikes per plant will be removed to count the number of immature and mature seeds per spike for a maximum of 50 spikes analysed for seeds per species. From this data, the average seed production per spike will be multiplied by the average spikes per plant, multipled by plants per hectare to estimate seed production per hectare throughout different seasons over 2 years, for invaded sites and uninvaded sites, which is useful for comparison with other grassland studies and to compare with animal removal rates in the other plant-granivore components of this PhD. Seed size and nutritional content will be analysed for a select number of species including buffel grass. | ||
| Fauna: | See Methodology 1 in Plant methods. Methodlogy 2: Ant foraging and diet: Granivorous ant colonies will be located in the one-hectare sites and marked with a GPS. Four randomly selected colonies per site will be monitored using GoPro and also visually for specific time intervals throughout the periods with highest ant forgaing activity. 4 ants per colony will be sampled and sent away off site for identification. The number of workers leaving the nest and returning (foraging activity), the proportion returning with food (forgaing success), the types of food items chosen (diet) and the proportion of seed chosen compared to the seed availability in the environment (seed preference) will be surveyed. Ants from those colonies will also be offered buffel grass seed on trays close to the nest, and then native seed, or vise versa, to determine if they can prey-switch between seed types. The total food intake per colony and per hectare will be calculated and compared to the total seed production for the one-hectare site, to determine whether certain seed types, particularly native seeds, are limiting in invaded areas and whether this is due to granivory. Vertebrate seed removal: 4 replicate seed cafeterias will be established at each site, each with a nominal amount of either native or buffel grass seed on separate trays, accessible to vertebrates only, and each with a camera trap focussed on the cafeteria. Seed trays and camera traps will be left out for 2 weeks at each site. The experiment will be conducted four times in one year to account for important seasonal differences in seed availability within the environment, which may translate into important differences in the community of seed-eating vertebrates in invaded and uninvaded areas. The amount of seed removed will be monitored during the 2 week period and at the end, and camera trap images will be reviewed to identify and count the frenquency of seed removal by different seed-eating species (e.g. Little Button-Quail, Zebra Finch, Budgerigar, Port Lincoln Ringneck Parrot, Crested Pigeon, Cockatiel, Splendid Fairy-wren, Bourke?s Parrot, Southern Whiteface, Spinifex Hopping Mouse, Hermannsburg Mouse, Desert Mouse, House Mouse). Standard 20 minute 2-hectare bird surveys using binoculars (Bird Atlas of Australia method) will also be conducted during one season only, concurrently with camera traps to assess the accuracy of camera traps in detecting birds and whether bird species in the area are using the seed trays. Methodology Component 3: Availability of Maku relating to overstorey trees I will accompany A?angu during bushfood trips in order to search for maku (root-dwelling larvae: witchetty grubs) Trips will be spread over the two years with at least 5 trips will be undertaken in invaded areas and 5 trips in native areas. Once at the location, maku searches will be conducted for a minimum of one hour per area (the exact time will be recorded) and I will collect data on the outcome of the searches including taking photos of maku to identify broad morpho types of maku (Liddle 2016), maku length and weight, time spent searching/digging per shrub, GPS location where the maku was found and associated vegetation parameters including host shrub species, size, and amount of vegetation cover in the under-storey where the maku was located (percent cover within 2 m2 radius of the host tree). I will later calculate catch per unit effort to standardise this methodology and also relate the catch data to site parameters such as fire history and cover abundance of buffel grass. | ||
| Data Distribution Rules: | Sensitive Dataset: Written permission required from Information Authority |
| Project Basis: |
Vegetation
:
Biological Survey of South Australia - Standard Survey methodology used.
Vegetation : Seed Collection Vegetation : Pest/Diseases/Threats - control project Fauna : Biological Survey of South Australia - Standard Survey methodology used. |
| Information Authority: |
Charles Darwin University
Anangu Pitjantjatjara Yankunytjatjara - APY Land Management |