Beyond prime areas of nature protection in East Africa: conservation ecology of a narrowly distributed Kenyan endemic bird species

Habel, Jan Christian; Teucher, Mike; Pschonny, Sandra; Rost, S.; Fischer, Christina

doi:10.1007/s10531-015-0998-1

Cited by 4 publications

(4 citation statements)

References 19 publications

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“…The average size of a fragment was 1.1 ha and primarily consisted of trees of small stature (<5 m). These fragments were widely distributed, with more than 80% of fragments separated by a distance of over 300 m (Habel, Teucher, Pschonny, et al, 2015). Human settlements (2.7%) comprised a very small portion of the study area and were clustered in four areas (Habel et al, 2019).…”

Section: Methodsmentioning

confidence: 99%

Bird movement patterns in an agricultural landscape are mediated by both habitat conditions and traits

Borah,

Beckman

2023

Biotropica

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Alterations of the landscape following agricultural expansion and intensification affect animal movement patterns in the resulting mosaic of fragments and surrounding matrix. Here, we analyze the observed movement patterns of 34 individuals from nine tropical bird species from a rapidly changing agricultural landscape in Kenya. We deconstructed the movement patterns into their three components: step length, turn angles, and displacement and categorized them into two states: area restrictive and expansive movement. Using hidden Markov models, mixed models, and species traits, we showed that movement of birds in the fragments comprised of short step lengths and small displacements, characteristic of area restrictive movement to exploit high‐quality habitats. On the contrary, movement in the matrix comprised of long step lengths and large displacements, characteristic of area expansive movement to explore or pass‐through poorer habitats. The responses of movement components to fragments and the surrounding matrix were mediated by species traits. Habitat specialists showed stronger boundary response, shorter step lengths, and smaller displacements than habitat generalists in both the fragments and the matrix. Their strong preferences for the fragments, coupled with low flight capabilities can make movement in the matrix particularly difficult. Whereas, at the landscape scale, habitat generalist omnivores and habitat specialist frugivores had larger step lengths than the other guilds, as they use the matrix for resources or as a conduit to movement. Therefore, the habitat fragments are intensely utilized and of conservation importance. The matrix quality and permeability can promote animal space use and movement.

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Section: Methodsmentioning

confidence: 99%

Bird movement patterns in an agricultural landscape are mediated by both habitat conditions and traits

Borah,

Beckman

2023

Biotropica

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“…Some populations occur at intermediate elevations around Thika, Sagana, and Oldonjo Sabuk [ 10 ]. Turdoides hindei is a cooperative breeder and forms distinct families consisting of two to 10 individuals [ 12 ]. The call repertoire includes a contact and an alarm call (JCH, own observations).…”

Section: Methodsmentioning

confidence: 99%

“…Turdoides hindei is a cooperative breeder and thus forms distinct family groups with sizes ranging between 2 and 10 individuals [ 12 ]. This allows to also study family specific call characteristics, which may play an outstanding role in social species, such as cooperative breeding birds.…”

Section: Introductionmentioning

confidence: 99%

Evolution of contact and alarm calls in the Kenyan endemic Hinde’s babbler (Aves: Passeriformes)

2018

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BackgroundSpatial isolation, diverging environmental conditions and social structures may lead to the differentiation of various traits, e.g. molecules, morphology and behaviour. Bird calls may provide important information on effects of geographic isolation and may reflect diverging ecological conditions related to altitude. Furthermore, bird calls are strongly shaped by the social behaviour of species. The Kenyan endemic bird Hinde’s Babbler, Turdoides hindei, is a cooperative breeder existing in distinct family groups. The species occurs in five isolated population groups at different altitudes across its distribution range in south-eastern Kenya. With this model species we test for potential effects of geographic isolation, diverging altitudes, and social structures. We recorded and analysed contact and alarm calls of T. hindei, including its entire distribution range and all existing population groups.ResultsOur data show significant differentiation of call characteristics among population groups across the species’ distribution range. This differentiation is correlated with geographical distance, but also with altitude. We also found strong call differentiation among neighbouring family groups. Call differentiation of contact calls was comparatively high in comparison to alarm calls, which showed a lower degree of divergence.ConclusionOur data show that call differentiation is governed by geographic isolation as well as altitude. Diverging degrees of call differentiation in contact and alarm calls suggests that both call types are under different selective pressures. Alarm calls are required to be understood by all members of the species across the entire distribution range and thus call differentiation is lower. In contrast, contact calls are more specific and differ even among neighbouring families supporting the maintenance of distinct bird families and groups.Electronic supplementary materialThe online version of this article (10.1186/s12862-018-1222-1) contains supplementary material, which is available to authorized users.

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“…Riparian forests provide important habitats for many endangered species (van Beukering and de Moel ), and various ecosystem services used by the local human population (Habel et al. 2015a). Demographic pressure in major parts of East Africa caused an increasing accumulation of people along rivers, with subsequent clearance of pristine riparian forests, its transformation into agricultural land and subsequent invasion and devastation by exotic species, such as L. camara .…”

Section: Introductionmentioning

confidence: 99%

Documenting the chronology of ecosystem health erosion along East African rivers

Habel

Teucher

Ulrich

et al. 2017

Remote Sens Ecol Conserv

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Pristine tropical ecosystems are currently suffering under extreme demographic pressure. This has led to habitat destruction and disturbances, an important precondition for the invasion of exotic species into pristine ecosystems, with detrimental effects on biodiversity. In this study, we analysed the chronology of land cover changes along rivers in south-eastern Kenya using historical aerial photographs and current aerial pictures taken from a drone. We assessed quantity and quality of riparian thickets along these rivers in 1961, 1980 and 2015/ 2016 and analysed effects of fundamental land cover changes on arthropod abundance and diversity. Our data show effects from demographic pressure by the increasing number of human settlements rising by 425% from 1961 to 2015/2016 (i.e. from 36 to 189 settlements). 58.5% of the land surface originally covered by pristine riparian forests was cleared and transformed into agricultural land. After clearance and agricultural usage it frequently became fallow land and was invaded by the exotic shrub species Lantana camara. While the total coverage of riparian vegetation did not change over time, its quality declined dramatically. Currently 36.6% of the cleared pristine riparian forest is covered by L. camara thickets, and only 22.5% of the pristine riparian forest has remained unchanged over time. This modification of the vegetation structure impacts biodiversity. The abundances of three guilds of arthropods significantly differed between pristine and L. camara-dominated riparian vegetation, with herbivorous arthropods and ants being more abundant in pristine than in L. camara-dominated vegetation. Our data show that habitat destruction and disturbance is the prerequisite for subsequent invasion by exotic plant species, having a strong effect on species composition and diversity at higher trophic levels.

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Beyond prime areas of nature protection in East Africa: conservation ecology of a narrowly distributed Kenyan endemic bird species

Cited by 4 publications

References 19 publications

Bird movement patterns in an agricultural landscape are mediated by both habitat conditions and traits

Bird movement patterns in an agricultural landscape are mediated by both habitat conditions and traits

Evolution of contact and alarm calls in the Kenyan endemic Hinde’s babbler (Aves: Passeriformes)

Documenting the chronology of ecosystem health erosion along East African rivers

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