Abstract:
To effectively conserve and manage species, it is important to (1) understand how they are
spatially distributed across the globe at both broad and fine spatial resolutions and (2) elucidate
the determinants of these distributions. However, information pertaining to the distributions
of many species remains poor as occurrence data are often scarce or collected with varying
motivations, making the resulting patterns susceptible to sampling bias. Exacerbating an
already limited quantity of occurrence data with an assortment of biases hinders their
effectiveness for research, thus making it important to identify and understand the biases
present within species occurrence data sets. We quantitatively assessed occurrence records of
126 reptile species occurring in the Kruger National Park (KNP), South Africa, to quantify the
severity of sampling bias within this data set. We collated a data set of 7118 occurrence records
from museum, literature and citizen science sources and analysed these at a biologically
relevant spatial resolution of 1 km × 1 km. As a result of logistical challenges associated with
sampling in KNP, approximately 92% of KNP is data deficient for reptile occurrences at the
1 km × 1 km resolution. Additionally, the spatial coverage of available occurrences varied at
species and family levels, and the majority of occurrence records were strongly associated with
publicly accessible human infrastructure. Furthermore, we found that sampled areas within
KNP were not necessarily ecologically representative of KNP as a whole, suggesting that areas
of unique environmental space remain to be sampled. Our findings highlight the need for
substantially greater sampling effort for reptiles across KNP and emphasise the need to
carefully consider the sampling biases within existing data should these be used for
conservation management decision-making. Modelling species distributions could potentially
serve as a short-term solution, but a concomitant increase in surveys across the park is needed.
CONSERVATION IMPLICATIONS : The sampling biases present within KNP reptile occurrence data inhibit the inference of fine-scale species distributions within and across the park, which limits
the usage of these data towards meaningfully informing conservation management decisions
as applicable to reptile species in KNP.
