Sustaining indigenous Maasai Alalili silvo-pastoral conservation systems for improved community livelihood and biodiversity conservation in East African rangelands

boundaries at each end of the four directions were demarcated with a help from the local field assistant for each specific village. The common local trails within the surveyed Alalili systems were considered as transects from which the radius was measured from the center to every end. A handheld GPS was used to measure the radius where we managed to walk toward the boundaries at each end for small-sized Alalili systems, while the boundaries of the large-sized Alalili systems were reached out by a field vehicle. The four radii were recorded in the field data sheet from which an average radius of each Alalili system was obtained. The radius was used to compute the actual ground area of a specific Alalili system (Eq 1). Moreover, Google background image in the Q-GIS environment was used to locate the extent in terms of sizes for each Alalili through digitization. The digitization of each Alalili polygon was done using Google Earth Pro with the image captured by Landsat/Copernicus from the baseline landcover maps taken between February 2018 to December 2020 [71]. The local field assistant helped to identify the boundaries of each Alalili in the zoomed satellite view on the screen. The two val- ues were compared and the average was taken into consideration to decide the actual area cov- ered by each Alalili system (Eq 2). A ¼ pr2 ðEq 1Þ Whereby, A is the actual ground area of Alalili (km2) and r is an average radius of Alalili (km) Estimated Area of Alalili ðhaÞ ¼ ðActual ground area ðhaÞ þ Digitized area ðhaÞÞ=2 ðEq 2Þ

Data were collected from late April to early December 2022 whereby the types of Alalili sys- tems (communal and private Alalili) were identified through participatory field visits and semi-structured interviews (SSI). The participatory field visits involved the research team com- prised of a research team leader, research assistant, DGO/RO, a leader, and other two members of the village rangeland management committee (local field assistants). The leader of the vil- lage rangeland management committee helped to identify the type of the visited Alalili sys- tems. SSI through focused group discussion with DGO/RO and the local field assistants, that adopted the guiding questionnaires and checklist [72], was used to determine other descriptive features of Alalili systems. This includes the approximated livestock herd size, livestock catego- ries accommodated by each surveyed Alalili system, age, approximated distance to water sources, management modality, and allocated time to open the Alalili for grazing. 2.6 Data analysis Mapping of the spatial distribution of the Alalili system across Alalili type, size, and land use categories was done in Q-GIS version 3.12.3. Prior to mapping, the area of Alalili was catego- rized into three classes (small, medium, and large). The class sizes were obtained via the stan- dardization method whereby all Alalili systems that had an area below the mean range (mean ± SE) were considered small, Alalili systems with an area within a mean range were considered medium and those with above mean range were regarded as large. Excel spread-

sheet for Windows 2011 was used in data processing, organization, and data sorting to ensure smooth analyses. The abundance and distribution of Alalili systems were presented in percent- ages and tabular forms depicting their proportional dispersion within the mapped rangelands of northern Tanzania and their respective land uses. The chi-square test was used to under- stand the variation of abundance and distribution across Alalili types and land use categories [33, 47]. Independent sample t-test was used to understand the variation of total area covered by Alalili systems across types while analysis of variance (ANOVA) was used to understand the variation of total area covered by Alalili systems across land use and size categories. Prior to analyzing the effect of land use and types of Alalili on the size of Alalili systems, the PLOS ONE Sustaining Alalili systems in rangelands of East Africa PLOS ONE | https://doi.org/10.1371/journal.pone.0303649 May 16, 2024 7 / 24