Abstract In order to gain insight into the pattern of bat species composition over altitude and the environmental variables driving the observed pattern, we compared data from moist southern and drier northern aspects of the Soutpansberg range in northern South Africa. Acoustical monitoring and additional capturing of bats was used for analysis of species distribution patterns and comparisons of community composition. Bat activity generally followed a linear decline with increasing altitude, possibly related to reproductive females preferring lower altitudes. Species richness followed a hump-shaped distribution on the northern aspect and across the transect, whereas a pattern of a linear decline was observed on the southern aspect. Our study strongly supports a previously published climate model for insectivorous bats which assumes that water availability linked with temperature determines the shape of altitudinal distribution in bat species. Step-wise selection from multiple regression models retained habitat type and/or measures of habitat structure in all final models, supporting several other studies in that vegetation correlated to altitude is a primary determinant of bat species distribution over altitude. This study also supports that the Soutpansberg is a biodiversity hotspot for bats and emphasises that conservation efforts should by no means ignore the lower altitudes.
The loss of roost sites is one of the major drivers of the worldwide decline in bat populations and roost site preferences, either natural or artificially provided, are not well known for African bat species specifically. In this study we focus on the preference for different artificial roost sites by insectivorous bats in macadamia orchards in northern South Africa. From June 2016 to July 2017 we monitored 31 bat houses, mounted on poles in six macadamia orchards, for presence of bats or other occupants. Twenty-one multi-chambered bat houses of three different designs were erected in sets of three. Additionally, five Rocket boxes, four bat houses in sets of two (painted black and white) and one colony bat house were erected. Bats were counted and visually identified to family or species level. From December 2016 to the end of March 2017 iButtons were installed to record and analyze temperature variation within one set of three bat houses. We related the occupancy of bat houses to the different types of houses and the environmental variables: distance to water, altitude and height of the bat houses above the ground. Overall bat house occupancy was significantly higher in the central bat house, in the set of three, and the black bat house, in the set of two. Mean temperatures differed between houses in the set of three with the central bat house having a significantly higher mean temperature than the houses flanking it. Our study might confirm previous assumptions that the microclimate of bat houses appears to be an important factor influencing occupancy. In conclusion, from the different bat houses tested in this study the designs we assume the warmest and best insulated attracted the most bats. Further research is needed on the preferred microclimate of different bat species, co-habitation within bat houses and the potential importance of altitude and distance to water. Our study provided little variation in both altitude and the distance to water.
The loss of roost sites is one of the major drivers of the worldwide decline in bat populations and roost site preferences, either natural or artificially provided, are not well known for African bat species specifically.In this study we focus on the preference for different artificial roost sites by insectivorous bats in macadamia orchards in northern South Africa.From June 2016 to July 2017 we monitored 31 bat houses, mounted on poles in six macadamia orchards, for presence of bats or other occupants.Twenty-one multichambered bat houses of three different designs were erected in sets of three.Additionally, five Rocket boxes, four bat houses in sets of two (painted black and white) and one colony bat house were erected.Bats were counted and visually identified to family or species level.From December 2016 to the end of March 2017 iButtons were installed to record and analyze temperature variation within one set of three bat houses.We related the occupancy of bat houses to the different types of houses and the environmental variables: distance to water, altitude and height of the bat houses above the ground.Overall bat house occupancy was significantly higher in the central bat house, in the set of three, and the black bat house, in the set of two.Mean temperatures differed between houses in the set of three with the central bat house having a significantly higher mean temperature than the houses flanking it.Our study might confirm previous assumptions that the microclimate of bat houses appears to be an important factor influencing occupancy.In conclusion, from the different bat houses tested in this study the designs we assume the warmest and best insulated attracted the most bats.Further research is needed on the preferred microclimate of different bat species, co-habitation within bat houses and the potential importance of altitude and distance to water.Our study provided little variation in both altitude and the distance to water.
Abstract More sustainable and environmentally friendly agricultural practices, including ecological intensification, are needed to reduce biodiversity loss and environmental degradation. We evaluated the potential of ecological intensification through the enhancement of pollination services in an intensively managed and insect‐pollinated crop, Macadamia integrifolia . We compared the effects and importance of agronomic practices that include agronomic input (i.e. irrigation and managed honeybees), orchard design requiring no external inputs (i.e. spatial orchard structure) and landscape factors in 10 South African macadamia orchards. In comparison to experimental pollinator exclusion, insect pollination increased the initial and final nut set by 304% and 23%, respectively. However, nut set was pollination limited as hand pollination further improved nut set. Flower visitation rates increased with the cover of semi‐natural habitats in the surrounding landscape (1 km radius). This effect was outperforming the effect of the number of managed honeybee colonies, as agronomic practice. Initial nut set increased with orchard design and flower visitation rates. Perpendicular orientation of the planted macadamia rows towards the semi‐natural habitats increased initial nut set more than threefold compared to parallel row orientation. The initial nut set was 80% higher at the edge to semi‐natural habitats than in the orchard centre. In contrast, agronomic practices, such as irrigation, did not increase initial nut set. Final nut set depended on the preconditions of the initial nut set, additionally, high altitudes and the position in the centre of the orchard had positive effects. Synthesis and applications : Pollination services were prerequisites for high yields in macadamia and could be improved without further agronomic input. Especially, the orchard design, that is, spatial arrangement of tree rows and semi‐natural habitats at local and landscape scales, was more important to boost insect pollination and the initial development of macadamia nuts than agronomic practices, such as high levels of irrigation. Considering the urgency to reduce the environmental impacts of agricultural production, we highlight the high potential of ecological intensification by a smart orchard design and the restoration and conservation of semi‐natural habitats in the orchards and their surrounding landscape.
Quantifying how multiple ecosystem services and functions are affected by different drivers of Global Change is challenging. Particularly in African savanna regions, highly integrated land-use activities created a landscape mosaic with flows of multiple resources between land use types. A framework is needed that quantifies the effects of climate change, management and policy interventions on ecosystem services that are most relevant for rural communities, such as provision of food, feed, carbon sequestration, nutrient cycling and natural pest control. In spite of progress made in ecosystem modelling, data availability and stakeholder interactions, these elements have neither been brought together in an integrated framework, nor evaluated in the context of real-world problems. Here, we propose and outline such framework as developed by a multi-disciplinary research network, the Southern African Limpopo Landscapes network (SALLnet). Components of the framework such as the crop model APSIM and the vegetation model aDGVM2 had already been parameterized and evaluated using data sets from savanna regions of eastern, western and southern Africa, and were fine-tuned using novel data sets from Limpopo. A prototype of an agent-based farm household model was developed using comprehensive farm survey information from the Limpopo Province of South Africa. A first test of the functionality of the integrated framework has been performed for alternative policy interventions on smallholder crop-livestock systems. We discuss the versatile applicability of the framework, with a focus on smallholder landscapes in the savanna regions of southern Africa that are considered hotspots of global change impacts.
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