Predicting avian distributions to evaluate spatiotemporal overlap with locust control operations in eastern Australia

Abstract

Abstract. Locusts and grasshoppers cause considerable economic damage to agriculture worldwide. The Australian Plague Locust Commission uses multiple pesticides to control locusts in eastern Australia. Avian exposure to agricultural pesticides is of conservation concern, especially in the case of rare and threatened species. The aim of this study was to evaluate the probability of pesticide exposure of native avian species during operational locust control based on knowledge of species occurrence in areas and times of application. Using presence-absence data provided by the Birds Australia Atlas for 1998 to 2002, we developed a series of generalized linear models to predict avian occurrences on a monthly basis in 0.58 grid cells for 280 species over 2 million km 2 in eastern Australia. We constructed species-specific models relating occupancy patterns to survey date and location, rainfall, and derived habitat preference. Model complexity depended on the number of observations available. Model output was the probability of occurrence for each species at times and locations of past locust control operations within the 5-year study period. Given the high spatiotemporal variability of locust control events, the variability in predicted bird species presence was high, with 108 of the total 280 species being included at least once in the top 20 predicted species for individual space-time events. The models were evaluated using field surveys collected between 2000 and 2005, at sites with and without locust outbreaks. Model strength varied among species. Some species were under-or over-predicted as times and locations of interest typically did not correspond to those in the prediction data set and certain species were likely attracted to locusts as a food source. Field surveys demonstrated the utility of the spatially explicit species lists derived from the models but also identified the presence of a number of previously unanticipated species. These results also emphasize the need for special consideration of rare and threatened species that are poorly predicted by presence-absence models. This modeling exercise was a useful a priori approach in species risk assessments to identify species present at times and locations of locust control applications, and to discover gaps in our knowledge and need for further focused data collection.

Spatially-Explicit Estimation of Geographical Representation in Large-Scale Species Distribution Datasets

“…This could explain why species distribution models based on the AFE data are occasionally inaccurate regarding the prediction of the species’ range edges [39]. Although the high reliability of true presence data is advantageous, omission of absence data may lead to inflated false presence rates when, for example, habitat suitability models are calculated [28], or species presence probabilities are estimated [12], [49]. The inclusion of additional data such as the Hultén & Fries atlas or local plant surveys could be used to provide a better estimation of presence and absence probabilities; for example, the Anthos database (http://www.anthos.es) with a spatial resolution finer than the 50-km spatial resolution of the metadata set covering the entire Iberian Peninsula and comprehensive for its many endemic species (see, e.g., [18]), or the open-access online database source initiative GBIF (http://www.gbif.org).…”

“…Large-scale comprehensive species distribution datasets are remarkably scarce [3], [4], [11], [12], [13]. This gap is most noteworthy for vascular plants in Europe, given the continent’s long history of botanical research.…”

Insecticide residues in Australian plague locusts (Chortoicetes terminifera walker) after ultra‐low volume aerial application of the organophosphorus insecticide fenitrothion

“…As such, locust outbreaks provide an important ephemeral food source for birds and are often accompanied by wide and diverse avian assemblages [2,3]. Locusts provide a rich source of protein (62% dry mass) and lipid (17% dry mass) for predators [4,5] and, in regions of inland Australia characterized by low rainfall and variable resource availability, provide valuable nutrients for the many bird species that descend on areas experiencing locust population increases [6]. Several of these species specialize on locust outbreaks and have been observed feeding on this superabundant food source, often in large flocks [7].…”

“…Consequently, locust outbreaks and avian reproductive events can co-occur [6] and, combined with the ability of avian species to gorge feed, increase the risk to avian populations from pesticide exposure beyond the scope of the standard risk-assessment paradigm. Furthermore, granivorous birds often feed their young with insects, broadening the risk.…”

Adverse effects of fipronil on avian reproduction and development: maternal transfer of fipronil to eggs in zebra finch Taeniopygia guttata and in ovo exposure in chickens Gallus domesticus

“…This unfortunately results in locust-control spray events often being coincident with peak breeding periods for many non-target animals. In Australia, over 100 different bird species are known to frequent areas that occasionally receive aerial application of fipronil for locust control (Szabo et al 2009). While little is known of the effects of fipronil on free-living birds there are many studies that have examined the impact of other pesticides on avian reproduction and development (DeWitt 1955;Fernie et al 2009;Lundholm 1997;Wiemeyer and Porter 1970).…”