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Secretarybird Sagittarius serpentarius population trends and ecology: insights from South African citizen science data.

Hofmeyr SD, Symes CT, Underhill LG - PLoS ONE (2014)

Bottom Line: This implies that in the Fynbos biome, at least, Secretarybirds have adapted to transformed environments to some degree.However, in the rest of the country it is likely that habitat loss, largely through widespread bush encroachment but also through agriculture, afforestation, and urbanisation, is a major threat to the species.The methods developed here represent a new approach to analysing data from long-term citizen science projects, which can provide important insights into a species' conservation status and ecology.

View Article: PubMed Central - PubMed

Affiliation: School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, Gauteng, South Africa; Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Cape Town, Western Cape, South Africa.

ABSTRACT
Data from two long-term citizen science projects were used to examine the status and ecology of a Red List species, the Secretarybird Sagittarius serpentarius (Vulnerable), in South Africa. The first phase of the Southern African Bird Atlas Project operated from 1987 until 1992, and the second phase began in 2007. The Coordinated Avifaunal Roadcounts (CAR) project began in 1993 and by 1998 had expanded to cover much of the south-eastern half of the country. Data submitted up until April 2013 were used. A new method of comparing reporting rates between atlas projects was developed. Changing reporting rates are likely to reflect changes in abundance; in this instance the data suggest that the Secretarybird population decreased across much of South Africa between the two atlas projects, with a widespread important decrease in the Kruger National Park. Habitat data from the CAR project were analysed to gain insight into the ecology of the species. Secretarybirds tended to avoid transformed habitats across much of the area covered by the CAR project. In the winter rainfall region of the Western Cape, which is characterised by heavily transformed fynbos vegetation, at least 50% of Secretarybirds recorded were in transformed environments. This implies that in the Fynbos biome, at least, Secretarybirds have adapted to transformed environments to some degree. However, in the rest of the country it is likely that habitat loss, largely through widespread bush encroachment but also through agriculture, afforestation, and urbanisation, is a major threat to the species. The methods developed here represent a new approach to analysing data from long-term citizen science projects, which can provide important insights into a species' conservation status and ecology.

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Southern African Bird Atlas Project (SABAP) comparison map for the Secretarybird, extracted 19 April 2013.This map compares SABAP1 and SABAP2 reporting rates. South African province names are given in black, neighbouring countries are labelled in grey, and the Kruger National Park, in the north-east of South Africa, is outlined in green. Coloured squares are quarter-degree grid cells (QDGCs; 15'×15') in which the species was observed in either project. Reporting rates are compared using the Z-statistic (see text). SABAP2 reporting rates were lower than SABAP1 in red, orange and yellow grid cells, and higher than SABAP1 in light and dark green and blue grid cells. In red grid cells Z<–2.58 (important decrease), in orange –2.58<Z<–1.64 (distinct decrease), and in yellow –1.64<Z<0 (decrease probably attributable to sampling variability). In light green grid cells 0≤Z<1.64 (increase probably attributable to sampling variability), in dark green 1.64<Z<2.58 (distinct increase), and in blue grid cells Z>2.58 (important increase). Pink grid cells are those which had not yet been covered in SABAP2. Therefore, red, orange and yellow grid cells indicate areas of potential conservation concern, whereas green and blue grid cells indicate areas of apparent population increase.
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pone-0096772-g001: Southern African Bird Atlas Project (SABAP) comparison map for the Secretarybird, extracted 19 April 2013.This map compares SABAP1 and SABAP2 reporting rates. South African province names are given in black, neighbouring countries are labelled in grey, and the Kruger National Park, in the north-east of South Africa, is outlined in green. Coloured squares are quarter-degree grid cells (QDGCs; 15'×15') in which the species was observed in either project. Reporting rates are compared using the Z-statistic (see text). SABAP2 reporting rates were lower than SABAP1 in red, orange and yellow grid cells, and higher than SABAP1 in light and dark green and blue grid cells. In red grid cells Z<–2.58 (important decrease), in orange –2.58<Z<–1.64 (distinct decrease), and in yellow –1.64<Z<0 (decrease probably attributable to sampling variability). In light green grid cells 0≤Z<1.64 (increase probably attributable to sampling variability), in dark green 1.64<Z<2.58 (distinct increase), and in blue grid cells Z>2.58 (important increase). Pink grid cells are those which had not yet been covered in SABAP2. Therefore, red, orange and yellow grid cells indicate areas of potential conservation concern, whereas green and blue grid cells indicate areas of apparent population increase.

Mentions: These results are presented as a map, which facilitates spatial interpretation and enables us to highlight areas of concern. We used a six-colour system to classify the Z-score for each QDGC into categories, using familiar values from the standard normal distribution as the cutpoints for the Z-scores, but without associating the usual significance levels with them (Figure 1). An additional category was created for QDGCs in which the species was recorded in SABAP1 but for which no checklists had been submitted for SABAP2 at the time of the data download.


Secretarybird Sagittarius serpentarius population trends and ecology: insights from South African citizen science data.

Hofmeyr SD, Symes CT, Underhill LG - PLoS ONE (2014)

Southern African Bird Atlas Project (SABAP) comparison map for the Secretarybird, extracted 19 April 2013.This map compares SABAP1 and SABAP2 reporting rates. South African province names are given in black, neighbouring countries are labelled in grey, and the Kruger National Park, in the north-east of South Africa, is outlined in green. Coloured squares are quarter-degree grid cells (QDGCs; 15'×15') in which the species was observed in either project. Reporting rates are compared using the Z-statistic (see text). SABAP2 reporting rates were lower than SABAP1 in red, orange and yellow grid cells, and higher than SABAP1 in light and dark green and blue grid cells. In red grid cells Z<–2.58 (important decrease), in orange –2.58<Z<–1.64 (distinct decrease), and in yellow –1.64<Z<0 (decrease probably attributable to sampling variability). In light green grid cells 0≤Z<1.64 (increase probably attributable to sampling variability), in dark green 1.64<Z<2.58 (distinct increase), and in blue grid cells Z>2.58 (important increase). Pink grid cells are those which had not yet been covered in SABAP2. Therefore, red, orange and yellow grid cells indicate areas of potential conservation concern, whereas green and blue grid cells indicate areas of apparent population increase.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4016007&req=5

pone-0096772-g001: Southern African Bird Atlas Project (SABAP) comparison map for the Secretarybird, extracted 19 April 2013.This map compares SABAP1 and SABAP2 reporting rates. South African province names are given in black, neighbouring countries are labelled in grey, and the Kruger National Park, in the north-east of South Africa, is outlined in green. Coloured squares are quarter-degree grid cells (QDGCs; 15'×15') in which the species was observed in either project. Reporting rates are compared using the Z-statistic (see text). SABAP2 reporting rates were lower than SABAP1 in red, orange and yellow grid cells, and higher than SABAP1 in light and dark green and blue grid cells. In red grid cells Z<–2.58 (important decrease), in orange –2.58<Z<–1.64 (distinct decrease), and in yellow –1.64<Z<0 (decrease probably attributable to sampling variability). In light green grid cells 0≤Z<1.64 (increase probably attributable to sampling variability), in dark green 1.64<Z<2.58 (distinct increase), and in blue grid cells Z>2.58 (important increase). Pink grid cells are those which had not yet been covered in SABAP2. Therefore, red, orange and yellow grid cells indicate areas of potential conservation concern, whereas green and blue grid cells indicate areas of apparent population increase.
Mentions: These results are presented as a map, which facilitates spatial interpretation and enables us to highlight areas of concern. We used a six-colour system to classify the Z-score for each QDGC into categories, using familiar values from the standard normal distribution as the cutpoints for the Z-scores, but without associating the usual significance levels with them (Figure 1). An additional category was created for QDGCs in which the species was recorded in SABAP1 but for which no checklists had been submitted for SABAP2 at the time of the data download.

Bottom Line: This implies that in the Fynbos biome, at least, Secretarybirds have adapted to transformed environments to some degree.However, in the rest of the country it is likely that habitat loss, largely through widespread bush encroachment but also through agriculture, afforestation, and urbanisation, is a major threat to the species.The methods developed here represent a new approach to analysing data from long-term citizen science projects, which can provide important insights into a species' conservation status and ecology.

View Article: PubMed Central - PubMed

Affiliation: School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, Gauteng, South Africa; Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Cape Town, Western Cape, South Africa.

ABSTRACT
Data from two long-term citizen science projects were used to examine the status and ecology of a Red List species, the Secretarybird Sagittarius serpentarius (Vulnerable), in South Africa. The first phase of the Southern African Bird Atlas Project operated from 1987 until 1992, and the second phase began in 2007. The Coordinated Avifaunal Roadcounts (CAR) project began in 1993 and by 1998 had expanded to cover much of the south-eastern half of the country. Data submitted up until April 2013 were used. A new method of comparing reporting rates between atlas projects was developed. Changing reporting rates are likely to reflect changes in abundance; in this instance the data suggest that the Secretarybird population decreased across much of South Africa between the two atlas projects, with a widespread important decrease in the Kruger National Park. Habitat data from the CAR project were analysed to gain insight into the ecology of the species. Secretarybirds tended to avoid transformed habitats across much of the area covered by the CAR project. In the winter rainfall region of the Western Cape, which is characterised by heavily transformed fynbos vegetation, at least 50% of Secretarybirds recorded were in transformed environments. This implies that in the Fynbos biome, at least, Secretarybirds have adapted to transformed environments to some degree. However, in the rest of the country it is likely that habitat loss, largely through widespread bush encroachment but also through agriculture, afforestation, and urbanisation, is a major threat to the species. The methods developed here represent a new approach to analysing data from long-term citizen science projects, which can provide important insights into a species' conservation status and ecology.

Show MeSH
Related in: MedlinePlus