Tourists scare off scavengers
A STUDY carried out at El Hondo natural park has found that outdoor recreation in natural spaces affects the key ecological processes of scavenging.
Researchers from Miguel Hernández and Alicante universities noted that outdoor recreation has increased in recent decades, intensifying after the Covid-19 lockdown.
Previous studies have shown that disturbances from this activity may affect species’ behaviour and fitness, but its effect on ecological processes has been overlooked, they noted. They tested the variety of terrestrial vertebrate scavenger species and scavenging patterns by placing 185 carcasses monitored with camera traps between February 2020 and May 2021 in a public access area and a restricted area of El Hondo.
Their results showed that outdoor recreation altered the composition of scavenger species, especially affecting large species such as raptors.
They found this very interesting because raptors’ home range is very extensive and they can move all over the park, but are reluctant to feed in the public access area.
“This wetland is an important wintering area for raptors, especially for some threatened species such as the greater spotted eagle, being its unique regular wintering area in Spain,” noted the researchers.
“Therefore, it is necessary to maintain areas restricted to
visitors where these species can rest and feed to ensure the viability of their populations.”
They also found that nonnative species scavenged almost four times more often on carcasses in public access areas than in the restricted areas, showing that human activities promote the presence of nonnative species ‘which are more tolerant and benefit from human presence’. In addition, these non-native species benefit from the fact that other larger, more human-elusive scavengers are scarcer in these areas, increasing the amount of carrion available to them and for longer periods of time.
“Furthermore, vertebrates completely consumed 68.2% of the carcasses in the restricted area, decreasing to 46.7% in the public access area.”
In the restricted area, consumption time was shorter (111.8 hours compared to 157.5) and consumed biomass by vertebrate scavengers was larger (73.9% vs. 52.2%) than in the public access area.
“Our study shows that outdoor recreation profoundly alters not only the scavenger assemblage but also key ecological processes such as carrion removal,” they assured.
Therefore, they maintain that to ensure biodiversity conservation it is necessary to maintain areas restricted to visitors where these species can rest and feed to ensure the viability of their populations.
“Although it is necessary and beneficial for human wellbeing to be in contact with nature, protected areas are refuges for biodiversity and are home to a large number of threatened species, so it is a priority to also maintain the ecological processes of the ecosystem to avoid the risk of them becoming ‘open-air zoos’, where species need to be maintained by external inputs,” the study concludes.
Maintaining spaces restricted to tourism is easy in large, uninhabited and inaccessible PAs, but highly complex and essential in ones that are easily accessible or close to anthropised areas, which tend to be smaller. They encourage managers and conservationists of small PAs to establish restricted access areas as a refuge for the species most sensitive to human activities in order to preserve the ecological functions these species provide to the ecosystem.