DOI: 10.5061/dryad.hx3ffbgrh
title: Ecosystem functions in East African forest and agro-environments

description: Natural and semi-natural habitats provide important resources for many
 plant and animal species. The destruction of such habitats might reduce
 biodiversity and disturb ecosystem functions. Sub-Saharan Africa suffers
 particularly under the destruction and deterioration of ecosystems due to
 demographic pressure. In this study, we analysed ecosystem functions in a
 small remnant of East African coastal forest and the surrounding
 anthropogenic landscape. We measured pollination activity, predation, and
 seed dispersal. For each study plot, we also recorded local habitat
 conditions, which may also influence ecosystem functions. We found no
 significant difference between the natural forest and anthropogenic
 agro-environments for seed dispersal nor pollination. Insect predation
 showed highest rates inside the forest and decreasing rates in the open
 agro-environments. Local environmental conditions strongly affected
 ecosystem functions. For example, flower availability showed positive
 effects on pollination activity, and the availability of herbs on the
 ground positively influenced the level of predation. Rather homogenous
 ecosystems such as eucalyptus plantations and arable land showed lowest
 levels of ecosystem functions. Here, planting of undergrowth such as herbs
 and flowers may improve ecosystem functions. Our findings underline that
 natural forest as well as heterogeneous agro-environments provide a large
 variety of ecosystem functions, which strongly depend on site-specific
 microhabitat conditions.
description: Our study area is located in southern Kenya, 20km north of
 Mombasa, at an elevation of about 40m a.s.l. The climate of this region is
 hot and humid year-round (with mean temperatures of 25.5 °C and average
 rainfall 1100 mm/a). The climate is characterised by strong seasonality,
 with two rainy seasons lasting approximately from end-March to July
 (average seasonal rainfall 631 mm) and from October to December (average
 rainfall 287 mm) (Jaetzold et al., 2010). The region shows medium to weak
 agricultural potential as characterised by the agro-ecological zonation of
 Coastal Lowlands with a medium to long cropping season, intermediate rains
 and a weak short second rainy season. The soils consist mainly of
 luvisols. The beginning and end of the rains vary strongly among years and
 especially the second rainy season is unreliable (Jaetzold et al., 2010).
  The landscape consists of a mosaic of different ecosystems, including
 natural- and semi-natural and anthropogenic ecosystems (Appendix A: Fig.
 A1a). In the centre of our study area there is the sacred Kaya Kambe
 forest, a small 75ha remnant of East African coastal forest (Fungomeli et
 al. 2020, Habel et al. 2023). Such Kaya forests (i.e. Mijikenda sacred
 forests) are found along the Indian Ocean coastline of southern Kenya
 (Robertson & Luke 1993, Githitho 2003, Matiku 2005,
 Shepeard-Walwyn 2014, Fungomeli et al. 2020), and represent small and
 geographically isolated forest patches (mean size 120.4ha, 75% smaller
 than 150 ha) (see Nyamweru et al. 2008, Shepeard-Walwyn 2014, Fungomeli et
 al. 2020). Despite its small habitat size and geographic isolation, these
 forest patches still provide suitable habitats for a large variety of
 typical and rare forest species (Luke & Githitho 2003, Wijtten et
 al. 2011, Habel et al. 2023). Human activities such as the removal of
 deadwood, selective tree logging, hunting and grazing of cows and goats
 have led to severe disturbances and subsequently to reduced vegetation
 regeneration with negative effects on biodiversity (Kibet 2011).**
 **Management and the protection of Kaya Kambe forest is controlled by the
 elders of the local community (Habel et al. 2023). Shifts in cultural
 beliefs and an increasing demand for land and forest products poses a
 severe threat to Kaya Kambe forest (Luke and Githitho 2003). The other
 habitat types are settlement area (Kambe village), orchards (with mango
 and banana trees mainly), arable land (mainly maize, sorghum, cowpeas),
 eucalyptus tree plantation, and shrubland (Luke and Githitho 2003). The
 study area is confined by a lead mine in the north and a road in the
 south. <strong>Study
 set-up</strong> We applied the Rapid Ecosystem
 Functions Assessment according to Meyer et al (2017). This low-tech method
 is easy to use and allows standardized collection of data on ecosystem
 functions (Meyer et al. 2015). We assessed the following proxies, all
 relevant to conduct successful agricultural farming: pollination activity,
 predation, and seed dispersal. These proxies are of high relevance for the
 production of food crops. Predation and thus regulation of pests may
 increase yields in agro-environments (Meyer et al. 2015). Pollination
 activity is a key ecosystem service for the production of seeds and thus
 yield stability (Isaacs et al. 2017, Bishop et al. 2022). Seed dispersal
 is another mutualistic interaction pivotal for effective regeneration of
 ecosystems due to animal-mediated seed dispersal (Meyer et al.
 2015). We measured these three proxies of ecosystem
 functions in natural habitats (the forest interior, forest edge),
 semi-natural habitats (orchards, shrubs), and anthropogenic habitats
 (plantations, agricultural fields, and settlements). Data collection was
 performed from 26th of February to 15th of March on 10x10m study plots,
 which were set in all habitat types. These study plots were arranged along
 habitat gradients from the forest interior and the forest edge (200m
 inside the forest, at the forest margin 8m from forest edge, and at the
 forest edge) into the semi-natural and anthropogenic habitats (8m distant
 from forest edge 16m, 32m, 64m and 128m distant from forest edge). It was
 not possible to have all transects at equal distance, but distances were
 in all case sufficient to minimize spatial autocorrelation. In part of the
 analyses we subsume the plots near the forest edge (-8m, 0m 8m) into a
 forest margin category. In total, ecosystem functions were measured along
 17 such gradients (Fig. A1a). We added further study plots in a eucalyptus
 plantation (Fig. A1a). Pollination activity was
 measured using coloured pan trap (white, blue, and yellow), all three
 mounted on a wooden stick about one meter above ground (Fig. A1b). These
 colours were chosen, as they are known to have highest sampling efficiency
 across a wide range of pollinators (Habel and Ulrich 2021). Pan traps were
 filled with saturated salt solution and a drop of detergent to reduce the
 surface tension and activated during the morning for 8 hours. Afterward,
 the collected material was taken from the field. We pooled counts of
 Hymenoptera, Diptera, Coleoptera, and Lepidoptera to estimate pollinator
 abundances. For measuring predation, we used green artificial caterpillars
 made out of plasticine. These 4cm long caterpillars were pinned on
 earth-coloured paper at the ground and were exposed in the field for 24h
 to measure predator activity during the day and night. In total, we
 established 10 artificial caterpillars per study plot. We considered bite
 marks on the dummies from arthropods, birds, small mammals, and slugs (see
 Meyer et al. 2017). We did not record bite mark frequency because one
 predator could cause multiple bite marks on the same dummy. Dummies, which
 vanished or got damaged by humans were not evaluated. Seed dispersal was
 measured by placing three seed plates (wooden plates with 25 small pits)
 at each plot and counted the removed seeds after 24 hours (Fig. A1b). We
 used peeled sunflower seeds. We did not consider the taxa that removed the
 seeds. All raw data are contained in Appendix B.
 <strong>Environmental
 characteristics</strong> We recorded the
 following habitat characteristics: Herb-, shrub-, tree-, canopy- and
 litter coverage (categorized into 0-25%, 25-50%, 50-75% and 75-100%).
 Furthermore, we assessed the average litter height (in cm) and the
 presence of dead wood (no, little, medium, much), as well as nectar
 sources (0, &lt;25, &lt;50, &lt;75, and &lt;100 blossoms).
 For comparability, these percentage and abundances classes were coded as
 0, 1, 2, 3. Raw data are provided in Appendix B.
description: # Ecosystem functions in East African forest and agro-environments depend
 on site-specific microhabitat conditions Dataset DOI:
 [10.5061/dryad.hx3ffbgrh](10.5061/dryad.hx3ffbgrh) ## Description of the
 data and file structure #### File: Appendix\_A.docx (Zenodo)
 **Description:** figures #### File: Appendix\_B.xlsx **Description:**  Raw
 data  ##### Variables **Sheet Pollination:** * Date: Date of sampling *
 Habitat: habitat type of sampling mentioned above and in the associated
 publication * Distance from forest edge [m]: Distance of the sampling
 point from the nearest forest edge as shown in Fig. 1 of the publication.
 Negative distance refers to the direction inside the forest, positive
 distance is the direction out of the forest, both measured from the forest
 edge (distance 0) * Trap colour: white - blue - yellow * Pollinator
 abundance: numbers of records of Hymenoptera, Coleoptera, Diptera,
 Heteroptera, and Lepidoptera * Hymenoptera - Thysanoptera: Numbers of
 records of the Arthropod order considered * Unidentifiable: Numbers of
 records not identified to order level (at most 1 record was not
 identified) * Caterpillars: Numbers of caterpillars in the traps * Herb,
 shrub, tree, canopy, dead wood, litter cover: Categories of cover 0:
 absent, 1: very low, 2: low, 3: intermediate, 4: high * Flower
 availability: Availability of nectar sources coded as 0 blossoms: code 0;
 &lt;25 blossoms: code 1; 25 - 49 blossoms: code 2; 50 - 74 blossoms: code
 3; 75 - 100 blossoms: code 4. **Sheet Predation** * Date: Date of sampling
 * Habitat: habitat type of sampling mentioned above and in the associated
 publication * Distance from forest edge [m]: Distance of the sampling
 point from the nearest forest edge as shown in Fig. 1 of the publication.
 Negative distance refers to the direction inside the forest, positive
 distance is the direction out of the forest, both measured from the forest
 edge (distance 0) * Arthropod bites: Numbers of bite marks in the
 artificial larvae * Bird and small mammal marks: Numbers of bite marks and
 displacements in the artificial larvae * Slug rasping: Marks of slug
 radulae on the artificial larvae * Herb, shrub, tree, canopy, dead wood,
 litter cover: Categories of cover 0: absent, 1: very low, 2: low, 3:
 intermediate, 4: high * Flower availability: Availability of nectar
 sources coded as 0 blossoms: code 0; &lt;25 blossoms: code 1; 25 - 49
 blossoms: code 2; 50 - 74 blossoms: code 3; 75 - 100 blossoms: code 4. *
 Sheet Seed dispersal * Date: Date of sampling * Habitat: habitat type of
 sampling mentioned above and in the associated publication * Seeds
 dispersed after 24h: Total numbers of seeds removed from the plate *
 Distance from forest edge [m]: Distance of the sampling point from the
 nearest forest edge as shown in Fig. 1 of the publication. Negative
 distance refers to the direction inside the forest, positive distance is
 the direction out of the forest, both measured from the forest edge
 (distance 0) * Flower availability: Availability of nectar sources coded
 as 0 blossoms: code 0; &lt;25 blossoms: code 1; 25 - 49 blossoms: code 2;
 50 - 74 blossoms: code 3; 75 - 100 blossoms: code 4.