Habitat preferences, estimated abundance and behavior of tree hyrax (Dendrohyrax sp.) in fragmented montane forests of Taita Hills, Kenya

Abstract

We studied a previously almost unknown nocturnal mammal, an apparently undescribed species of tree hyrax (Dendrohyrax sp.) in the moist montane forests of Taita Hills, Kenya. We used thermal imaging to locate tree hyraxes, observe their behavior, and to identify woody plants most frequently visited by the selective browsers. We also documented acoustic behavior in forest fragments of different sizes. Data on calling type and frequency were analyzed together with lidar data to estimate population densities and to identify forest stand characteristics associated with large populations. Viable populations were found only in the largest forest fragments (> 90 ha), where tree hyraxes preferred most pristine forest stands with high, multilayered canopies. The estimated population sizes in smaller forest fragments were very limited, and hyraxes were heard to call only during late night and early morning hours, presumably in order to avoid detection. While we frequently recorded tree hyrax songs in the largest forest fragments, we almost never heard songs in the small ones. All remaining subpopulations of the Taita tree hyrax are under threat of human disturbance and further habitat deterioration. Conservation efforts should include protection of all remaining habitat patches, but also reforestation of former habitat is urgently needed.

Species identity and behavior of cave‐dwelling tree hyraxes of the Kenyan coast

“…Tree hyrax species can be identified by their calls (Oates et al, 2022;Roberts et al, 2013). Calling activity and pattern of tree hyraxes correlate with population size and level of human disturbance (Rosti et al, 2022).…”

“…They also need hollow trees or other hideouts, where they spend most of the day (Gaylard & Kerley, 2001 ; Kundaeli, 1976 ; Milner & Harris, 1999b ; Opperman et al, 2018 ). Tree hyraxes use woody climbers for moving between trees, and dense growths of tangled lianas provide hideouts for the animals (Allen & Loveridge, 1927 ; Kingdon, 1971 ; Rosti et al, 2022 ). Tree hyraxes are vocally very active, and their acoustic communication can be used to distinguish between different species (Hoeck et al, 2014 ; Oates et al, 2022 ; Roberts, 1999 , 2001 ; Rosti et al, 2020 ).…”

“…Tree hyraxes are vocally very active, and their acoustic communication can be used to distinguish between different species (Hoeck et al, 2014 ; Oates et al, 2022 ; Roberts, 1999 , 2001 ; Rosti et al, 2020 ). Previously, tree hyraxes have been thought to be solitary (Kundaeli, 1976 ), but recent findings from the Taita Hills in Kenya suggest that they can be highly social (Rosti et al, 2022 ). Tree hyraxes have short legs, and their ability to migrate between isolated forest fragments is poor.…”

“…Tree hyrax population density is usually estimated by analyzing the calling rate, as their sightings are rare (Rosti et al, 2022 ). The highest population densities of tree hyraxes have been found in large and intact natural forests (Topp‐Jørgensen et al, 2008 ).…”

Two new species of Phronia Winnertz, 1864 (Diptera, Mycetophilidae) from Taita Hills, Kenya

“…The slopes of Taita Hills were formerly covered by moist montane forest of which only fragments are left, but these areas still accommodate a considerable diversity of species including endemic taxa (cf. Rosti et al 2022).…”