Study area and data acquisition
Approximately 580,367 km2 in size, Kenya is situated
between latitudes 5 N and 5 S and longitudes 34 and 42. Kenya’s
predominant bimodal rainfall and temperature patterns are determined by
the Inter-Tropical Convergence Zone (ITCZ). Kenya’s topography is
diverse, with elevations ranging from 0 to 5197 meters above sea level.
The dry land mass is typically represented by six agro-ecological zones:
agroalpine (0.1%), high potential (9.3%), medium potential (9.3%),
semi-arid (8.5%), and dry (52.9%). Agro-pastoralists and pastoralists
predominately live in the semi-arid to very arid zones which make up
80% of the country . Kenya has 28 national reserves totaling 18,042
km2 (11.7%), 22 national parks totaling 29,357
km2 (5.16%), and 160 conservancies totaling 36,300
km2 (11.0%). Kenya has 68 important biodiversity
areas (IBAs), with 55 of them threatened .
All raptor species’ occurrence data for the years 2013 to 2020 was
acquired from the Global Biodiversity Information Facility’s online
platform (https://www.gbif.org/,
https://doi.org/10.15468/dl.hzyp6v, GBIF, 7th September, 2021). A
total of 11529 records were obtained. These data were used to project
the overall occurrence distribution of raptor occurrence in Kenya. From
these data, we then selected raptor species that were endangered and/or
threatened based on their IUCN status and selected the following five
raptors: Steppe Eagle (Aquila nipalensis ) (EN), Secretary bird
(Sagittarius serpentarius ) (EN), Martial Eagle (Polemaetus
bellicosus ) (EN), Bateleur (Terathopius ecaudatus ) (EN), and
Southern ground hornbill (Bucorvus leadbeateri ) (VU). As
previously stated , in order to fully cover the raptor’s entire climatic
and environmental range, records for the entire nation of Kenya were
downloaded . OpenRefine software Version 2.1 was used for cleaning,
which included removing duplicate records and records without
georeferences. In order to eliminate data points with spatial
correlation, and ensure independence, all records were checked in R for
spatial autocorrelation using the K nearest neighbor analyses . We
retained the following occurrence points following cleaning: Steppe
Eagle, n=169; Martial Eagle n=267; Secretary bird, n=191; Bateleur,
n=676; and Southern ground hornbill, n=25, for a total of 1328
occurrence records. We only modelled for species with more than 20
records of occurrence to warrant the precision of the estimates of
species niches. These records were then used to produce SDMs.