Invertebrate and vertebrate predation rates in a hyperarid ecosystem following an oil spill

Abstract

Extreme temperatures and scarce precipitation in deserts have led to abiotic factors often being regarded as more important than biotic ones in shaping desert communities. The presumed low biological activity of deserts is also one reason why deserts are often overlooked by conservation programs. We provide the first quantification of predation intensity from a desert ecosystem using artificial sentinel prey emulating caterpillars, a standardized monitoring tool to quantify relative predation pressure by many invertebrate and vertebrate predators. The study was conducted in a protected natural area affected by oil spills in 1975 and 2014; hence, we assessed the potential effects of oil pollution on predation rates. We found that predation was mostly due to invertebrate rather than vertebrate predators, fluctuated throughout the year, was higher at the ground level than in the tree canopy, and was not negatively affected by the oil spills. The mean predation rate per day (12.9%) was within the range found in other ecosystems, suggesting that biotic interactions in deserts ought not to be neglected and that ecologists should adopt standardized tools to track ecological functions and allow for comparisons among ecosystems.

Attack rates on artificial caterpillars in urban areas are higher than in suburban areas in Colombia

“…These results are in agreement with those reported by Ferrante et al (2022) and Sam et al (2015) in other experiments using artificial larvae. Despite that, the general trend is for arthropods to be the main predators (Ferrante et al 2014, 2017a, 2019, 2021, Magagnoli et al 2018, Molleman et al 2016, Pena et al 2021). The fact that the most common markings found on models fitted those of birds does not mean that these are the main predators in urban environments.…”

“…Similarly, predation intensity is difficult to measure because predation events will often leave only fragments of the consumed prey, or no trace at all. The sentinel prey method is an alternative way to measure predation (Ferrante et al 2021, Howe et al 2009). This technique consists of manipulating prey availability by locating a known number of prey (artificial or live) and recording the rate of disappearance or traces of predation after a given period of exposure (Ferrante et al 2021, Lövei & Ferrante 2017).…”

“…The sentinel prey method is an alternative way to measure predation (Ferrante et al 2021, Howe et al 2009). This technique consists of manipulating prey availability by locating a known number of prey (artificial or live) and recording the rate of disappearance or traces of predation after a given period of exposure (Ferrante et al 2021, Lövei & Ferrante 2017). This method has been successfully used to estimate predation pressure on caterpillars (Ferrante et al 2014, Howe et al 2009, 2015, Loiselle & Farji-Brener 2002, Richards & Coley 2007, Tvardikova & Novotny 2012).…”

Predation on artificial caterpillars following understorey fires in human‐modified Amazonian forests

“…Furthermore, this methodology allows the identification of predators by assessing the types of marks left on the "predated" artificial caterpillars (Low et al, 2014), which is key to comparing the role of different predator groups on the control of folivorous arthropods (Ferrante et al, 2021;Lemessa et al, 2015;Roslin et al, 2017;Sam et al, 2015).…”

“…Even though the predation on artificial caterpillars is often lower in comparison with natural prey (Lövei & Ferrante, 2017; Nagy et al, 2020), the technique is still a robust way of comparing predation incidence between habitat types (Roels et al, 2018; Schwab et al, 2021; Tvardikova & Novotny, 2012). Furthermore, this methodology allows the identification of predators by assessing the types of marks left on the “predated” artificial caterpillars (Low et al, 2014), which is key to comparing the role of different predator groups on the control of folivorous arthropods (Ferrante et al, 2021; Lemessa et al, 2015; Roslin et al, 2017; Sam et al, 2015). For example, in primary rainforests in Costa Rica, arthropods accounted for 86% of all predation incidences on artificial caterpillars, whilst birds accounted for just 11% (Seifert et al, 2015).…”