4.4.1.1 Habitat Analysis
The PATN cluster analysis of trappable species data produced the dendrogram of similarity in Figure 6. The dendogram shows two closely related habitat types. This was expected given the vegetation structure observed was similar and the majority of species were recorded from both habitat types. However, species recorded from trap site 3 differed in the field from the remaining fauna assemblage by capturing two species of burrowing frog which were not recorded from any of the other sites. The PATN cluster did not select this site out based on the trapping data.
Figure 6: Fauna habitat similarity dendrogram.
4.4.2 SURVEY ADEQUACY
Systematically obtained data (trapping results for terrestrial fauna and set-time survey for birds, excluding opportunistic data) was analysed for survey adequacy. Mammal, reptile and amphibian trapping data were combined for analysis as ‘terrestrial vertebrate fauna’, as these fauna groups were sampled using the same methods. The invertebrate fauna species were separated and analysed. It should be noted that the invertebrate dataset comprises of individuals collected from species groups that potentially include SRE species such as scorpions, slaters and pseudoscorpions. Species such as common spider groups were not included in the analysis.
Species Accumulation Curves (SACs) were generated through 10,000 randomisations of the sample sequence of the data sets for trappable fauna and avifauna. The SE line reflects the actual number of species recorded.
The Michaelis-Menten (MM) means (1 run) line represents the predicated total number of species that could be recorded if additional survey effort were undertaken.
Analysis of the terrestrial vertebrate trapping data produced a climbing SAC (Figure 7). An asymptote was not yet reached. Visually the shape of the curve in this SAC indicates that the number of species recorded was still increasing and additional survey effort would have recorded additional species. Extrapolation of the MM curve suggests that 92% of the theoretical total number of terrestrial fauna able to be trapped had been captured at the completion of the 28 trap nights of the Level 2 vertebrate fauna survey (Table 19). The value of the MM mean estimator is 32.5 whereas the species observed was 30 (Table 19). The results of the MM mean estimator indicates that additional trapping may have recorded a few more species.
11344-3930-17R final 42 Figure 7: Species Accumulation Curve for Trappable Vertebrate Fauna
The SAC analysis of the avifauna set‐time survey dataset also produced a typical SAC, almost reaching the asymptotic plateau (Figure 8). Used as a stopping rule, the MM estimator indicated that at the completion of the systematic bird surveys (34 set-time surveys) the survey was to 70% sufficient. The MM mean estimator generated the highest theoretical maximum of 33 species (Table 19), suggesting further survey effort would have detected approximately 10 additional species.
Figure 8: Species Accumulation Curve for Observed Avifauna
SAC analysis of the collected invertebrate species produced a similar SAC to the avifauna SAC, almost reaching the asymptotic plateau (Figure 9). The MM mean estimator indicated that at the completion of the systematic invertebrate fauna collection (dry pitfall and leaf litter collection) the survey was to 79% sufficient.
0 5 10 15 20 25 30 35
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
No. of Species
Sampling Effort
Trappable Vertebrates SAC
S(est)
MMMeans (1 run)
0 5 10 15 20 25 30 35 40
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
No. of Species
Sampling Effort
Avifauna SAC
MMMeans (1 run) S(est)
11344-3930-17R final 43 The MM mean estimator generated the highest theoretical maximum of 25 species (Table 19), suggesting further survey effort would have detected another five species of invertebrate species.
Figure 9: Species Accumulation Curve for Collected Invertebrate Species
Parametric analysis of systematically obtained survey data for birds and terrestrial faunal groups (reptiles, non-volant mammals, amphibians and invertebrate) revealed that survey effort was adequate. Table 19 provides a summary of the theoretical maximum number of species using the MM mean estimator which provides the most accurate representation of the potential species number with 32.5 trappable vertebrates, 33.3 bird species and 25.3 invertebrates predicted. This is compared against the actual number of species observed, with any inconsistencies smoothed by an algorithm (Mao Tau) which simulates an infinite number of randomisations of the sample order.
Table 19: Mean estimates of total species richness
Richness Estimators Trappable
Vertebrates Birds Invertebrates
Michaelis-Menten 32.5 33.3 25.3
Species Trapped/Recorded 30 24 20
Total Species Observed 38 30 20
0 5 10 15 20 25 30
1 6 11 16 21 26 31 36 41
No. of Species
Sampling Effort
Invertebrate SAC
S(est)
MMMeans (1 run)
11344-3930-17R final 44 4.4.3 ZOOLOGICAL LIMITATIONS
Table 20: Zoological limitations Possible limitations
Constraints (yes/no):
Significant, moderate or negligible
Comment
Competency/experience of the
consultant carrying out the survey No constraints
All survey staff have relevant recent experience surveying in a number of bioregions including the Kimberley, Murchison, Gascoyne, Pilbara and the Wheatbelt region.
Scope (what faunal groups were sampled and were some sampling methods not able to be employed because of constraints such as weather conditions)
No constraints
Sampling techniques were deemed adequate and sufficient. The majority of faunal groups were sampled and no constrains were experienced.
Proportion of fauna identified,
recorded and/or collected No constraints
All vertebrate fauna individuals were identified in the field. Where further identification was necessary, the individuals were taken back to camp, identified and released within 24 hours of capture. All fauna was released at the point of capture. Invertebrate fauna was collected, kept cool and euthanised in cool ethanol and submitted to external taxonomists for identification (Bennelongia). Species accumulation curves revealed that the majority of vertebrate fauna and invertebrate fauna was sampled during the current survey, however further sampling would have recorded additional species.
Sources of information (historic/recent
or new data) No constraints
A large number of surveys have been undertaken previously in the region (within 80 km of the study area) which results in a detailed knowledge of the faunal assemblage of the area. Database search results were consulted in a thorough manner and assisted in the assessment of fauna values on a regional level.
Proportion of the task achieved and further work that may need to be undertaken
No constraints
The level of surveying required was assessed to be a Level 1 fauna survey; however NBY decided that a more detailed Level 2 fauna survey was the more adequate survey effort. All components of a Level 2 survey were completed with a total of four
systematic trapping sites, 10 opportunistic foraging sites for vertebrate and SRE fauna, 14 birding sites, four SM2 bat recorder sites and four leaf litter collection sites.
Timing/weather/season/cycle No constraints
The survey was conducted in May, shortly after the rain season when temperatures were warm and moisture was still present. Reptile activity and consequently detection rates were relatively high and amphibians were active due to the moisture present during night time. Bird activity was high in the morning periods and the majority of the expected avian species was recorded.
Disturbances which affected results of the survey (e.g. fire, flood, accidental human intervention)
No constraints No disturbances were experienced in connection with the survey effort or results.
11344-3930-17R final 45 Possible limitations
Constraints (yes/no):
Significant, moderate or negligible
Comment
Intensity of survey No constraints
Level 2 surveys are the most intensive survey type in accordance with EPA, OEPA and DBCA guidance. A one phase Level 2 assessment was carried out and was appropriate for the project.
Completeness (e.g. was relevant area
fully surveyed) No constraints
All representative habitat types were sampled adequately. Some access restriction existed, however less accessible areas of the study area were accessed and sampled on foot. This is not expected to have impacted the completeness of sampling as all habitats were surveyed in detail.
Resources (e.g. degree of expertise
available for species identification) Negligible
All vertebrate fauna was identified in the field.
Invertebrate SRE fauna was submitted to external taxonomists who experienced some issues in the liaison with WA Museum staff and collection. This may have impacted the regional knowledge of invertebrate species distribution and regional information on the unnamed Ctenotus sp.
(leonhardii group). However, these issues had a negligible impact on the final results.
Remoteness and/or access problems No constraints All areas of the study area have been accessed and sampled adequately.
11344-3930-17R final 46