PlantLife Volume 55.9, July 2023. Outcomes of the 5th City Nature Challenge

Outcomes from southern Africa's 5th City Nature Challenge

by Suvarna Parbhoo

The City Nature Challenge (CNC) is a 4-day weekend event held annually at the end of April to celebrate both Citizen Science Month and Spring in the northern hemisphere. The goal of the CNC is to encourage residents to explore and photograph the wildlife observed in their city’s open spaces. Initiated in 2016 in the state of California, the CNC began as a competition between Los Angeles and San Francisco. This exciting event quickly grew nationally and internationally, with the City of Cape Town representing southern Africa in 2019. Now, just 5 years later, 31 cities across southern Africa have participated in the CNC, alongside 482 cities from 46 countries.

Figure 1: Increase in CNC participation across southern Africa over the past 5 years (2019-2023)

The CNC ascertains the most biodiverse city globally by assessing the number of observations made, the number of species recorded and the number of people participating in each city. For southern Africa, we also measure the number of people identifying the observations as this is the key aspect of the Challenge that allows the observations to be made into useful foundational biodiversity data. Over the past 5 years, the data collected in southern Africa has been exponential with 2022 being a mega year of participation, probably due to the relaxed pandemic protocols after 2 years. This year’s results were marginally lower than last year, which we deduce is a reflection of monotony from the big data driven southern African cities. However, there is ample space for the 30 southern African cities to climb the regional CNC leader board, showcase their biodiversity, and make meaningful data contributions.

 

Table 1: Comparison of the participation, contributions of observations and identifications made to species level during the southern Africa CNC participation over the past 5 years (2019-2023)

Event	Observations made	Species observed	Participants	Identified observations
CNC 2019	46 901	4 045	1 280	1 286
CNC 2020	56 530	5 043	1 506	1 032
CNC 2021	112 668	8 116	1 896	1 923
CNC 2022	139 480	8 602	2 786	2 011
CNC 2023	123 207	8 555	2 323	1 364

The southern African CNC participants are a combination of novice and skilled iNatters with interests ranging from broad environmental concerns to observing specific taxonomic groups (iNaturalist collates observations of 11 groups of organisms – from the big mammals to the tiny fungi). Citizens new to making observations of wildlife unknowingly contribute data (for example alien species) useful for answering ecological questions.

 We are fortunate to have several citizen science communities who encourage the development of scientific knowledge and skills within their membership or interest group networks. The Custodians of Rare and Endangered Wildflowers (CREW) is a South African citizen science programme, celebrating its 20th anniversary this year, with remarkable success in collecting recent occurrence records and threats of plant species of conservation concern as well as rediscovering plants not seen for a long time as well as finding plant species new to science. While the skilled CREWites have found delight in joining the CNC craze, the timing of the Challenge (outside of the typical flowering season) has also provided a dedicated time to search for long lost species, amongst other plant species listed in the threatened categories.

 South Africa has a variety of data collection projects set up on iNaturalist. They run on an ongoing basis to collect data at both taxonomic and ecosystem level for meaningful analysis by the conservation authorities, responsible for managing and reporting on biodiversity at the municipal scale. The annual increase in the number of both invasive alien species and species of conservation concern that were recorded during the CNC (bearing in mind that the Challenge ran at the tail-end of the region’s flowering season) is indicative of the meaningful contribution that can result from an activity targeted as a fun-filled way of exploring nature.

Table 2: Records of the number of invasive species and threatened species recorded in South Africa during the CNC over the past 5 years (2019-2023)

Event	Invasive species	Threatened species
CNC 2019	167	312
CNC 2020	128	92
CNC 2021	247	465
CNC 2022	222	560
CNC 2023	245	551

Noticeably, for the five years of its participation, southern Africa remained proudly at the top of the global leader board for both observations made and species observed, despite having much lower participation than other cities. A collective 1,870,763 observations of 57,227+ species (including more than 2,570 species of conservation concern) were made by 66,394 observers during the CNC 2023. The CNC 2023 global results showed the Top 3 cities for observations made were La Paz (Bolivia), Cape Town (South Africa) and Dallas (USA).

The CNC 2023 southern Africa results revealed that eThekwini, Weskus and Nelson Mandela Bay climbed up the leader board and newcomers Buffalo City and Potchefstroom contributed over 1000 observations. CNC 2023 southern African participation gathered 123, 847 observations of 8,645+ species (551 of species of conservation concern) made by 2,368 observers. The species numbers were made possible by 1,576 identifiers spending long hours painstakingly identifying the observations over the 10-day CNC identification phase. 

The Top 3 cities for species contributed during CNC 2023 were La Paz (Bolivia), Hong Kong (China) and Cosala (Mexico). Cape Town came in close at #4 and Garden Route at #15 made the global Top 20 leader board. Whilst the most-observed species globally was the Mallard duck  (Anas platyrhynchos), southern Africa’s Bietou (Osteospermum moniliferum) was the most observed species in the region. Cape Dwarf chameleon (Bradypodion pumilum) was the most observed threatened species with just under 100 observations, Protea lepidocarpodendron (NT) the most observed threatened plant species and Lantana camara (Category 1B) the most observed invasive alien species.

Figure 2: A collage of most observed species during CNC 2023

How incredible to see the magnificent species observed across the globe over just one weekend. The success of the CNC is diverse, from making citizens aware of nature in their immediate surroundings and biodiversity practitioners collecting significant information to bringing change in networking with different communities and increasing knowledge. Huge appreciation to each of the participating cities’ (southern Africa especially) organisers for the dedicated time and effort in planning events in their cities to Bioblitzing and spending hours on identification. Certainly, the Challenge would not be successful without our passionate champions, who are preparing to do it all over again for the Great Southern Bioblitz (GSB) 24-27 November 2023.

About the author: Suvarna Parbhoo Mohan is the manager of the CREW programme at the SANBI where she has progressed in the field of threatened plant conservation since 2006. She is passionate about human capital development by engaging with students across various higher education institutes and mentoring individuals as they take on internships and progress into the work force. Apart from Suvarna’s  leadership role within the CREW programme, she is Chair of the Botanical Society KZN Coastal Branch, where she actively support the activities of plant conservation. Suvarna serves as co-Chair of the IUCN Species Survival Commission (SSC) Southern African Plant Specialist Group to ensure the members are actively contributing to the targets set for the quadrennium 2021-2025.