Activity patterns and fine‐scale resource partitioning in the gregarious Kihansi spray toad Nectophrynoides asperginis in captivity

Abstract

Understanding the behavior of species threatened with extinction is important for conservation planning and for solving problems facing species in captivity and the wild. We examined diurnal activity budgets and habitat use of the extinct in the wild Kihansi spray toad to provide insights into ongoing conservation initiatives for this species. Observations on eight target behaviors were made each morning and evening for 14 days, in two subpopulations at Kihansi and University of Dar es Salaam captive breeding centers. There were significantly more bouts of resting than calling, amplexing, hunting, walking, climbing, or feeding. There was no difference in mean time spent in each activity between the two subpopulations. The use of habitat was variable between age classes, subpopulations and sampling time. Young toads spent significantly more time resting at the top of vegetation and on walls while adults rested more on logs. Further, adults foraged more on the walls and vegetation in the morning and on the ground in the evening. Contrastingly, young toads foraged more on the ground in the morning and switched to elevated patches during evening. The similarity of the toads' behavior suggests that important biological traits are still maintained in captivity and retained across toad generations. Furthermore, temporal and spatial variations in the use of habitat structures between age groups suggest fine-scale resource partitioning to reduce competition in this gregarious species. These results highlight the importance of maintaining diverse habitat structures in captivity and are useful for planning species reintroduction and future restocking programs.

Daily activity profile of the golden mantella in the “Froggotron”—A replicated behavioral monitoring system for amphibians

“…Temperatures cooler than 18°C result in lower activity levels even if humidity is above 80%. Rija et al (2014) obtained similar results in Kihansi spray toads ( Nectophrynoides asperginis ) after they compared activity levels at different times of day, temperatures and relative humidity. Equally, a study by Köhler et al (2011) concentrated on activity levels and optimal body temperatures for common frogs ( Rana temporaria ) and found that jump lengths peaked at an optimal temperature and shortened with a decrease in temperature.…”

Effects of land‐use changes on the conservation of re‐introduced toads, Nectophrynoides asperginis

“…LULCC is aided by human activities such as infrastructure development and agriculture, which threaten species through habitat loss, fragmentation and destruction (Doe et al, 2022; Franco‐Belussi et al, 2020; Mmbaga et al, 2017; Ngongolo et al, 2020; Ngongolo & Mtoka, 2013; Sigala et al, 2022). It has also been reported that human‐induced LULCC triggers ecological changes that lead to a decrease in biodiversity and increased species loss (Franco‐Belussi et al, 2020; Rija et al, 2011).…”

“…The KST was estimated to have 20,000 individuals at the time of its discovery (prior to dam construction; Nahonyo, 2019). Due to habitat dryness influenced by water diversion after dam construction, there was a decrease in the number of toads (Rija et al, 2011). Artificial sprinkler systems were created to mimic natural sprays, which led to a rise in toads in 2001 (Nahonyo, 2019; Rija et al, 2011).…”

“…Due to habitat dryness influenced by water diversion after dam construction, there was a decrease in the number of toads (Rija et al, 2011). Artificial sprinkler systems were created to mimic natural sprays, which led to a rise in toads in 2001 (Nahonyo, 2019; Rija et al, 2011). Toad numbers fell precipitously again between 2003 and 2004, and no toads were heard or seen in their natural habitat.…”

Local Habitat Characteristics Determine Butterfly Diversity and Community Structure in a Threatened Kihansi Gorge Forest, Southern Udzungwa Mountains, Tanzania

“…However, recent bird assessment reported no signi cant changes in bird community structures between pre and post hydropower construction periods (Werema and Msuya 2019) suggesting that impacts were probably only associated with some species. Further, some amphibian species such as the critically endangered Kihansi spray toad was severed, led its declaration as extinct in the wild species by International Union for Conservation of Nature-IUCN (Rija et al 2010), although reintroduction of the species into the gorge is ongoing (Rija et al 2014). Also, some plant species such as Coffea kihansiensis and Cupea jonii, remain critically endangered or threatened as their habitats have not fully recovered following the habitat disturbance (Rija et al 2011;Vollesen 2000).…”