Great Southern BioBlitz 2025 Part 1 Overall Results and Analysis

During the Great Southern BioBlitz 2025, a total of 282,261 observations were recorded, documenting 37,550 unique taxa and contributed by 9,993 observers. These results highlight the continued growth and success of the BioBlitz as a major citizen science initiative in the Southern Hemisphere, with strong participation across multiple countries and taxonomic groups.

Table 1. Overall Participation and Taxonomic Coverage in the Great Southern BioBlitz 2025

Observer group	Observations	Unique taxa	Observers	Taxa per observer
All observers	282261	37549	9993	3.76
Observers with > 10 records	263524	35803	2995	11.95

Year-by-Year Trends (2020–2025)

From 2020 to 2025, the Great Southern BioBlitz showed consistent year-on-year growth:

•             Observations increased from 70,959 (2020) to 282,261 (2025)

•             Unique taxa more than doubled, from 14,875 to 37,550

•             Observer participation nearly quadrupled, from 2,512 to 9,993

This sustained growth reflects increasing public engagement, improved geographic coverage, and rising biodiversity awareness across the Southern Hemisphere.

Year-by-year summary of observations, unique taxa, and participating observers recorded during the Great Southern BioBlitz (2020–2025).

Year	Observations	Unique taxa	Observers	Taxa per observer
2020	70959	14874	2512	5.92
2021	170925	27300	5376	5.08
2022	188606	28779	5775	4.98
2023	216313	32656	6829	4.78
2024	249719	33023	8241	4.01
2025	282261	37549	9993	3.76

Trends in Observation Effort (2020–2025)

As illustrated in Figure 1, the Great Southern BioBlitz has experienced a strong and consistent increase in total observations since 2020. Observation numbers rose sharply from just over 70,000 records in 2020 to more than 280,000 records in 2025, representing a nearly fourfold increase over six years. While the largest jump occurred between 2020 and 2021, likely reflecting both increased awareness and improved digital participation tools, subsequent years continued to show steady growth. This sustained upward trend indicates not only growing public interest but also improved retention of participants and repeat engagement across BioBlitz events.

The continued rise in observations through 2025 suggests that the BioBlitz has successfully expanded its reach geographically and taxonomically, with participants contributing more records across a wider range of habitats and regions in the Southern Hemisphere.

Figure 1. Number of observers contributing to the GSB in each year 2020-2025

Growth in Taxonomic Diversity

Patterns in Figure 2 closely mirror those observed for total observations, demonstrating a strong positive relationship between participation effort and biodiversity coverage. The number of unique taxa recorded more than doubled between 2020 and 2025, increasing from fewer than 15,000 taxa to over 37,500 taxa.

 Notably, although total observations increased each year, the rate of taxonomic accumulation began to stabilise slightly after 2023. This pattern is consistent with ecological sampling dynamics, where early increases capture many common species, while later growth increasingly reflects the detection of rarer, cryptic, or geographically restricted taxa. The renewed increase in 2025 highlights the ongoing contribution of experienced observers and targeted efforts that enhance the detection of less frequently recorded species.

Figure 2 Number of unique taxa recorded in the GSB in each year 2020-2025.

Participation Efficiency and Observer Contribution

When considered alongside participation metrics, the charts also reflect changes in observer behaviour over time. While total observer numbers increased substantially, the average number of taxa recorded per observer gradually declined from 2020 to 2025. This trend likely reflects the successful recruitment of many new participants, including first-time contributors, who typically record fewer taxa per person than highly experienced observers. Importantly, observers contributing more than ten records accounted for the majority of observations and taxa, underscoring the critical role of highly engaged participants in driving data quality and depth.

Citizen Science Impact

Together, these trends demonstrate the growing scientific and societal value of the Great Southern BioBlitz. The increasing volume of observations and expanding taxonomic coverage directly support biodiversity research, conservation planning, and environmental monitoring at continental scales. The documentation of rare and threatened species, along with exceptionally high amphibian diversity recorded in South American countries, highlights the BioBlitz’s capacity to generate data of global ecological significance.

GSB 2025 further reinforced the event’s role as the largest spring biodiversity initiative in the Southern Hemisphere, successfully combining public engagement with meaningful scientific outcomes. By uniting professional scientists and citizen observers, the BioBlitz continues to strengthen biodiversity awareness, promote conservation action, and build long-term capacity for community-driven environmental stewardship.

Contribution of Top Observers and Taxonomic Specialists

A key strength of the Great Southern BioBlitz lies not only in broad public participation but also in the exceptional contributions of highly active observers and taxonomic specialists. In 2025, a relatively small subset of participants, those contributing more than ten observations, accounted for the vast majority of records and unique taxa documented. These highly engaged observers were responsible for over 93% of all observations and more than 95% of recorded taxa, highlighting their critical role in driving both data volume and biodiversity coverage (Table 1).

Observers with the highest numbers of recorded taxa made a particularly important contribution to the scientific value of the BioBlitz. Their ability to identify a wide range of organisms across multiple taxonomic groups significantly enhanced species inventories and improved the detection of rare, cryptic, and regionally restricted taxa. Such contributions are especially valuable for under-recorded groups, including amphibians, invertebrates, and lesser-known plant taxa.

The presence of experienced observers also supports data quality through accurate identifications and community-based validation, strengthening the reliability of records for downstream research and conservation use. At the same time, their participation fosters mentorship and learning within the citizen science community, encouraging skill development among newer participants.

Together, the combined efforts of highly prolific observers and first-time contributors underscore the collaborative nature of the Great Southern BioBlitz. This balance between expert-driven depth and broad community engagement continues to underpin the event’s success, ensuring both high-quality biodiversity data and sustained growth in citizen science capacity across the Southern Hemisphere.

Top 10 observers in 2025

username	Observations
craigpeter	4487
tonyrebelo	4422
nicklambert	2544
michaelcincotta	2265
adele84	2148
jandrevanzyl	2133
moocattle	2123
jacob-crisp	1666
bioshots_jm	1417
lindelani_gama	1416

Top 10 species chasers in 2025

Observer	Unique taxa observed
nicklambert	1682
moocattle	1137
michaelcincotta	958
adele84	866
lindelani_gama	815
jacob-crisp	780
dianadavey	774
jandrevanzyl	745
tonyrebelo	728
drmattnimbs	718

The GSB By continent

Africa

Africa led the 2025 Great Southern BioBlitz in total observations, powered by strong participation and especially high plant recording. Birds were also a standout among vertebrates, showing the strength of both botanical and birding effort across the region. Africa emerged as the most intensively documented continent during the Great Southern BioBlitz 2025, recording the highest number of observations overall. This strong performance was driven by a relatively compact but highly productive observer community, resulting in a solid taxa-per-observer ratio. Plants dominated the dataset, reflecting both the region’s botanical richness and strong engagement by plant-focused observers, while birds stood out as the most frequently recorded vertebrate group. Invertebrate records were led by insects, particularly beetles, flies, and butterflies, highlighting both ecological diversity and targeted recording effort in savannas, forests, and urban greenspaces.

Oceania

Oceania had the biggest community turnout and the highest overall taxonomic richness in 2025, reflecting broad engagement across Australia, New Zealand, and nearby islands. Insects—particularly butterflies and moths—were a major driver of both observations and diversity. Oceania stood out for its exceptional participation and taxonomic breadth, achieving the highest number of unique taxa recorded in the BioBlitz. With the largest observer base, the continent demonstrated strong community engagement, particularly in Australia and New Zealand. Insects were the dominant contributors to both observations and diversity, with Lepidoptera and Coleoptera especially prominent. Plant records were also extensive, reflecting the floristic richness of the region and sustained observer interest. Although taxa per observer was lower than in Africa or South America, the sheer scale of participation and coverage made Oceania the most comprehensive continental snapshot of biodiversity in the 2025 event.

South America

South America delivered one of the strongest biodiversity signals per participant, with observers recording richly diverse species lists. Amphibians were a highlight, with the continent recording the greatest amphibian diversity in the 2025 dataset. South America delivered one of the strongest biodiversity returns per observer, with fewer participants generating disproportionately high taxonomic diversity. This pattern suggests highly skilled observers working in species-rich ecosystems, particularly in tropical and subtropical regions. Amphibians were a notable highlight, with South America recording the greatest amphibian diversity among all continents—an expected but still striking result given the region’s global importance for amphibian biodiversity. Insects again formed the bulk of observations, but plants and vertebrates were also well represented, underscoring the continent’s ecological complexity. Overall, South America’s results emphasize depth of biodiversity over sheer volume of participation.

Table 6 Summary of the GSB by continent

Continent	Records	Unique taxa	Observers (all)	Taxa per observer (all)	Observers (>10 records)	Taxa per observer (>10)
Africa	122752	15106	2154	7.01	1024	14.45
Oceania	115695	16963	5687	2.98	1296	12.34
South America	43814	10997	2153	5.11	675	15.06

The Great Southern BioBlitz (GSB) 2025 demonstrated remarkable geographic breadth and participation across the Southern Hemisphere and beyond, with notable variation in scale and intensity by country. Australia and South Africa were the clear leaders in overall contributions, together accounting for over 196,000 observations and more than 25,000 unique taxa, reflecting both high biodiversity and strong observer engagement. New Zealand, Brazil, Colombia, Ecuador, Bolivia, and Peru also made substantial contributions, each recording thousands of observations and rich taxonomic diversity supported by hundreds of observers. Several countries with smaller observer pools nevertheless stood out for exceptionally high taxa-per-observer ratios, including Eswatini, New Caledonia, Botswana, Namibia, and Zimbabwe, highlighting highly efficient and focused participation (Table 6). Emerging or smaller-scale contributions from countries such as Angola, Gabon, Samoa, Tanzania, and Malawi still added valuable biodiversity records, underscoring the importance of inclusive regional participation. Overall, the 2025 BioBlitz showcased both the power of large, well-established citizen science communities and the outsized impact that smaller, highly engaged groups can have on documenting biodiversity across diverse ecosystems.

Table 6 Summary of the Great Southern BioBlitz 2025 by country

Country	Observations	Unique taxa	Observers	Taxa per observer
Angola	164	121	13	9.31
Argentina	672	338	46	7.35
Australia	93062	13495	4606	2.93
Bolivia	7445	2541	347	7.32
Botswana	1925	935	25	37.40
Brazil	10674	3950	571	6.92
Chile	1585	823	138	5.96
Colombia	8780	3039	443	6.86
Ecuador	8881	3169	265	11.96
Eswatini	867	553	7	79.00
Gabon	108	99	5	19.80
Kenya	6600	1635	114	14.34
Malawi	356	264	24	11.00
Moçambique	2001	1148	66	17.39
Namibia	2900	1047	43	24.35
New Caledonia	3589	1455	36	40.42
New Zealand	18943	4048	1039	3.90
Peru	4377	1725	214	8.06
Rwanda	468	288	45	6.40
Samoa	101	56	12	4.67
South Africa	103380	12434	1733	7.17
Tanzania	48	41	7	5.86
Uruguay	1400	817	131	6.24
Zambia	762	496	26	19.08
Zimbabwe	3173	1481	61	24.28

The Great Southern BioBlitz 2026 dates have been announce and the Umbrella project set up, this year the evet rolls into November 27-30.