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Habitat variables associated with encounters of Hottentot Buttonquail Turnix hottentottus during flush surveys across the Fynbos biome
Abstract
The Hottentot Buttonquail Turnix hottentotus is an endangered terrestrial turnicid and is endemic to the Fynbos biome, South Africa. Due to its secretive nature and apparent rarity almost nothing is known about the species, but its range has been subject to anthropogenic modification, invasion by alien plant species and is vulnerable to climate change. To model covariates associated with the presence of Hottentot Buttonquail we undertook flush surveys across the Fynbos biome, covering 275 km. Habitat variables at encounter sites were recorded in vegetation plots, as well as locations without encounters. There was a critical number of observers needed during a flush survey in order to account for buttonquail presence, with no encounters with less than five participants. After accounting for this, we found probability of encounters decreased with increasing time-since-fire. Probability of encounters were also negatively associated with increasing percentage grass and other vegetation cover. We also found no association between percentage cover of Restionaceae plants and encounter probability, considered previously to be the best indicator of Hottentot Buttonquail presence. This information will be of use to those interested in managing habitat for this species and should inform future conservation efforts.
... Likewise, little reliable inference on populations can be made from citizen science atlas data (Lee et al. 2017): our survey revealed their presence at locations with very high atlas coverage. In order to adequately survey for the presence of Hottentot Buttonquail, and likely other open landscape Turnix species, flush survey lines of a minimum of five people are required to walk substantial distances to cover large enough areas (Lee et al. 2018). ...
... Modelling suggested Hottentot Buttonquail presence was associated with time-since-fire veld of 2-5 years; and negatively associated with steep slopes, which is in agreement with Lee et al. (2018), as well as areas experiencing large mean diurnal or annual temperature fluctuations. The presence of the species was negatively associated with transformed landscapes. ...
There is remarkably little documented information in the scientific literature on any of the 18 species of buttonquail as they are very difficult to observe in the wild. This lack of information has hampered informed conservation decision making. We undertook the first biome-wide survey for the fynbos endemic Hottentot Buttonquail Turnix hottentottus , using flush transect surveys covering 275 km. We used location data for sightings as well as from records reported by the bird-watching community and modelled distribution using MaxEnt. Encounters were restricted to the fynbos biome, and the top contributors to our prediction of suitable habitat were habitat transformation, slope and time since fire. We obtained a density estimate of 0.032 individuals per hectare which, across an estimated median range of 27,855 km ² , provides a population estimate of 89,136 individuals. Given the extent of the range and the population estimate we suggest the IUCN Red List status could be ‘Vulnerable’, rather than ‘Endangered’. Agricultural and alien-vegetation encroachment means that the future of the species is certainly under threat and further studies are needed to inform conservation management.
... As a consequence, silent extinction processes can occur, as happened with the Andalusian Buttonquail , and this could be a risk for those taxa with a high concern index. However, as research on them continues, more detailed knowledge is coming to light, allowing the downlisting of the Black-breasted Buttonquail and the Fynbos Buttonquail from Endangered to Vulnerable (Lees & Smith 1999, Smyth & Pavey 2001, IUCN 2022 and Least Concern (Lee et al. 2017, IUCN 2022), respectively, giving some hope for those understudied species and subspecies. ...
... However, the intensification of agricultural practices poses a threat to those populations that inhabit agricultural systems. Due to the unobtrusive nature of buttonquails, there is a notable lack of field-based studies (Lee et al., 2017) and thus most of the knowledge about their basic biology has originated from observations on captive individuals (i.e. Bell and Bruning, 1974;Flieg, 1973). ...
The last populations of threatened taxa usually survive in low-impacted areas, whose protection and management is critical for its conservation. However, they can also be located in humanized and highly dynamic areas, whose management can be extremely challenging. The Andalusian buttonquail (Turnix sylvaticus sylvaticus) is the critically endangered nominal subspecies of the common buttonquail, a largely unknown species due to its secretive habits. Here, we show how the last Andalusian buttonquail population is restricted to a small, intensively used agricultural area (4,675 ha) in the Atlantic coast of Morocco, where the birds adapt their life cycle to a fast crop rotation. Buttonquails occupy crops in the flowering and fruiting stages, thus changing the preferred crop types along the year, although Alfalfa fields were occupied in all seasons. We used estimated occupancy rates in different crops to obtain seasonal (2017) and year-to-year population estimates (2011, 2014 and 2017). Numbers showed wide seasonal fluctuations between the lowest in winter and the maximum in summer (112–719 individuals). Year-to-year summer estimates also showed wide variations and large uncertainties, ranging between a maximum 1,890 estimated in 2011 and a minimum in 2014 with 492 individuals. The last population estimate available was 596 in 2017. The area is suffering a rapid shift from traditional irrigation farming towards practices more akin to commercial industrial agriculture. The conservation of this critically endangered taxon is highly dependent on the maintenance of traditional farming practices and a rational on-site agricultural modernization.
Significance
Changing interactions between climate and fire are impacting biodiversity. We examined the longest vegetation survey record in the Fynbos, South Africa, a fire-prone Mediterranean-type ecosystem and Global Biodiversity Hotspot, finding significant impacts of prolonged hot and dry postfire weather and invasive plants on species diversity. Graminoids, herbs, and species that sprout after fire declined in diversity, whereas the climatic niches of species unique to each survey showed a 0.5 °C increase in maximum temperature. The consequences of these changes for the structure and function of this ecosystem are largely unknown. This interaction between fire and changing climate is cause for concern in fire-prone ecosystems subject to severe summer droughts and temperature extremes, such as southern Australia, California, and South Africa.
Abstract
Estimates of bird numbers through quantification of density and range sizes are necessary for decisions regarding conservation status, yet counts of birds are often confounded by uncertainty of detection. The status of the endemic birds of the fynbos biome is of interest due to their conservation value in a global biodiversity hotspot, the ecological services they provide, and their importance for the avitourism industry. We conducted an extensive repeated point count survey in 2013 across the fynbos biome, South Africa, to determine probability of detection and covariates of site occupancy for 27 bird species, including 6 fynbos endemics. Detection of most species was influenced by time, temperature or vegetation height. Important covariates influencing site occupancy were vegetation height, altitude, time since fire and habitat type. Site occupancy for four fynbos endemic species was positively associated with increasing altitude. We further conducted point counts and mist-netting in eastern regions of the fynbos to calculate local density and standardized capture rates. A linear regression analysis showed that capture rates were a function of bird densities, but that several species were captured at higher rates than expected, notably nectarivorous species. During mist-netting a relative abundance count was conducted. We expected deviation of the fit of the regression of capture rates on relative abundance to correlate with detection probability, as we expect this index to underestimate skulking and cryptic species, but there was no correlation. Estimated species richness indices were highest for the biome-wide survey, and lowest for mist-netting due to the body size limit posed by the capture technique. Overall, we show that point counts are an effective method for surveying birds in the fynbos and that mist-netting can be used to create an index of relative abundance for smaller species, but that this can be affected by subjective placement of nets.
The South African Fynbos biome, a global biodiversity hotspot with high endemism and species richness,
has six endemic bird species. These are important not only intrinsically, but also for ecological
functioning and as flagships for South Africa’s economically valuable avitourism sector. Little is known
about population sizes or realised distribution ranges of these six species, but projected range modelling
based on occurrence from the South African Bird Atlas Project (SABAP) has suggested these
species are vulnerable to climate change. We estimate global population sizes for these six endemics
based on densities calculated from two intensive biome-wide point count surveys in 2012. We
modelled regions of suitable climatic space, from which we established that mean annual temperature
and the temperature of the warmest quarter of the year appear to limit Cape Rock-jumper
Chaetops frenatus and Protea Canary Serinus leucopterus ranges. Both species have seen an apparent
> 30% decrease in range and reporting rates (a proxy for abundance) in the twenty years
between SABAP atlas periods (1987–1991 and 2007–ongoing). The Cape Rock-jumper result is
unexpected: encounter rates are higher in shorter vegetation, dry slopes and habitats with more
recent occurrence of fire – all proxies for proximate causes of climate change on the Fynbos.
Although coastal plains are highly transformed, mountain Fynbos is the best protected of all the
world’s Mediterranean-climate habitats, with relatively little anthropogenic land transformation.
Long term weather datasets from the Fynbos demonstrate significant warming since 1960. We
conclude from these lines of evidence that these decreases are consistent with the loss of suitable
climate space and inability of these species to adjust physiologically to increasing temperatures.
We studied the foraging habitat of the endangered black-breasted button-quail (Turnix melanogaster) in 13 rainforest patches of an agricultural landscape (23.4 km2) in eastern Australia to assess its use of fragmented habitats outside conservation reserves. The species foraged only in the three largest patches (17.4, 40.0, 63.8 ha in size), all of which were connected to open eucalypt forest, and in intact rainforest. Occurrence of birds was greatest in the largest patch. The maximum number of individuals within the study area was estimated to be 22. Radio-tracking of nine birds revealed that three were resident in the largest patch for periods of over 100 days; no movements between patches were detected. Three radio-tagged birds were taken by avian and mammalian predators. Our results indicated that the long-term future of the species in agricultural landscapes is bleak and that management action is urgently needed to arrest its decline in these ecosystems.
Mediterranean climate is found on five continents and supports five global biodiversity hotspots. Based on combined downscaled results from 23 atmosphere-ocean general circulation models (AOGCMs) for three emissions scenarios, we determined the projected spatial shifts in the mediterranean climate extent (MCE) over the next century. Although most AOGCMs project a moderate expansion in the global MCE, regional impacts are large and uneven. The median AOGCM simulation output for the three emissions scenarios project the MCE at the end of the 21(st) century in Chile will range from 129-153% of its current size, while in Australia, it will contract to only 77-49% of its current size losing an area equivalent to over twice the size of Portugal. Only 4% of the land area within the current MCE worldwide is in protected status (compared to a global average of 12% for all biome types), and, depending on the emissions scenario, only 50-60% of these protected areas are likely to be in the future MCE. To exacerbate the climate impact, nearly one third (29-31%) of the land where the MCE is projected to remain stable has already been converted to human use, limiting the size of the potential climate refuges and diminishing the adaptation potential of native biota. High conversion and low protection in projected stable areas make Australia the highest priority region for investment in climate-adaptation strategies to reduce the threat of climate change to the rich biodiversity of the mediterranean biome.
Tools for performing model selection and model averaging. Automated model selection through subsetting the maximum model, with optional constraints for model inclusion. Model parameter and prediction averaging based on model weights derived from information criteria (AICc and alike) or custom model weighting schemes.
[Please do not request the full text - it is an R package. The up-to-date manual is available from CRAN].
An annotated species list of the alien vascular plant flora of the Cape of Good Hope Nature Reserve is presented. The flora comprises five gymnosperm and 68 angiosperm species that are definitely alien to the reserve and four angiosperm species that are possibly alien. The life-form distribution of the alien flora is shown to be significantly different from that of the indigenous flora; trees, shrubs and annual herbs are more important in the alien flora, and dwarf shrubs and perennial herbs are much less important. Biotic factors are suggested as being important in determining the success of alien invasions, in particular grazing by ungulates. The invasion rate is currently about one new species per year. By ceasing to introduce tree species and by restricting human disturbance, the rate of invasion of new species could be reduced.
Fifteen Black-breasted Button Quail
Turnix melanogasterwere trapped and banded at three of
ten trap stations in remnant vine forest between a young Hoop Pine
Araucaria cunninghamii plantation and agricultural land.
Eleven individuals were tagged with radio-transmitters. Four individuals
yielded sufficient data for home range analysis. Home range estimates ranged
from 2.2 to 6.1 ha. Home ranges overlapped considerably (both within and
between sexes). One male was found on a nest incubating three eggs, located at
the junction of two overlapping female territories. Another nest containing
two eggs appeared to have been abandoned. Observed roosts were found among the
buttress roots of larger trees in the vine forest; roosting positions changed
across nights. Radio-tracked birds were found solely within Microphyll Vine
Forest and sometimes within lantana thickets within the vine forest. No use
was made of surrounding agricultural land or young hoop pine plantation,
although elsewhere in the region birds have been observed in older hoop pine
plantations and a closed eucalypt forest with a well developed understorey.
Invasive alien organisms pose a major threat to global biodiversity. The Cape Peninsula, South Africa, provides a case study of the threat of alien plants to native plant diversity. We sought to identify where alien plants would invade the landscape and what their threat to plant diversity could be. This information is needed to develop a strategy for managing these invasions at the landscape scale. We used logistic regression models to predict the potential distribution of six important invasive alien plants in relation to several environmental variables. The logistic regression models showed that alien plants could cover over 89% of the Cape Peninsula. Acacia cyclops and Pinus pinaster were predicted to cover the greatest area. These predictions were overlaid on the current distribution of native plant diversity for the Cape Peninsula in order to quantify the threat of alien plants to native plant diversity. We defined the threat to native plant diversity as the number of native plant species (divided into all species, rare and threatened species, and endemic species) whose entire range is covered by the predicted distribution of alien plant species. We used a null model, which assumed a random distribution of invaded sites, to assess whether area invaded is confounded with threat to native plant diversity. The null model showed that most alien species threaten more plant species than might be suggested by the area they are predicted to invade. For instance, the logistic regression model predicted that P. pinaster threatens 350 more native species, 29 more rare and threatened species, and 21 more endemic species than the null model would predict. Comparisons between the null and logistic regression models suggest that species richness and invasibility are positively correlated and that species richness is a poor indicator of invasive resistance in the study site. Our results emphasize the importance of adopting a spatially explicit approach to quantifying threats to biodiversity, and they provide the information needed to prioritize threats from alien species and the sites that need urgent management intervention.
Resumen: Organismos invasores poseen una amenaza grave para la biodiversidad global. La Península Cape, en Sudáfrica provee un caso de estudio de la amenaza de plantas invasoras sobre la diversidad nativa de plantas. Intentamos identificar si las plantas pueden invadir el paisaje y cual sería su amenaza sobre la diversidad de plantas. Esta información es necesaria para desarrollar una estrategia para el manejo de estas invasiones a escala de paisaje. Mediante el uso de modelos de regresion logística predecimos la distribución potencial de seis especies de plantas invasoras importantes en relación con diversas variables ambientales. Los modelos de regresión logística mostraron que las plantas invasoras podrían cubrir mas de un 89% de la Península Cape. Acacia cyclops y Pinus pinaster fueron predecidas como las especies que cubrirían mas área. Estas predicciones fueron sobrepuestas en un mapa de distribución actual de la diversidad de plantas nativas de la Península Cape con la intención de cuantificar la amenaza de las especies invasoras sobre la diversidad de especies nativas. Definimos la amenaza a la diversidad de plantas nativas como el número de especies de plantas nativas (divididas como: todas las especies, especies raras y amenazadas y especies endémicas) que tienen su rango total cubierto por la distribución predecida de plantas invasoras. Un modelo nulo que asume una distribucióñ aleatoria de sitios invadidos se empleó para evaluar si el área invadida estaba siendo confundida con la amenaza de la diversidad sobre plantas nativas. De hecho, el modelo de regresión logística predijo que Pinus pinaster amenaza a 350 especies nativas, 29 consideradas raras y amenazadas y 21 especies endémicas mas de lo que el modelo nulo predijo. Las comparaciones entre los modelos nulos y logísticos sugieren que la riqueza de especies y la invisabilidad estan positivamente correlacionadas y que la riqueza de especies es un indicador pobre de la resistencia contra invasiones en el área de estudio. Nuestros resultados hacen énfasis en la importancia de adoptar aproximanciones espacialmente explícitas para cuantificar las amenazas contra la biodiversidad y proveer la información necesaria para priorizar amenazas por especies invasoras y los sitios que necesitan una intervención de manejo urgente.
Schemes are set out for the location of noda of nature reserves aimed at protecting the floral diversity of Fynbos vegetation in the Cape Floral Region, in South Africa, using distributional data on the Proteaceae. Species richness is significantly correlated between the Proteaceae and other major families and genera of plants representative of Fynbos, for which data are available. In our ideal scheme, 95% of all vascular plant species could be accommodated in 16% of the area occupied by Fynbos vegetation. However, several of our ideal-world noda are not viable options for Fynbos protection. Hence, we identify additional nodal areas that could be proclaimed as nuclei for nature reserves and incorporated into a real-world option for maximizing the protection of Fynbos floral diversity.
Blackrumped Buttonquail The atlas of southern African birds
- D Allan
- B Colahan
- Ja Harrison
- Dg Allan
- Lg Underhill
- M Herremans
- Aj Tree
- V Parker
- Cj Brown
Fynbos Vegetation of southern Africa. Cape Town
- Rm Cowling
- D Richardson
- Pj Mustart
The Eskom red data book of birds of South Africa
- M R Taylor
- D S Peacock
- R M Wanless
Taylor MR, Peacock DS, Wanless RM. 2015. The Eskom red
data book of birds of South Africa, Lesotho and Swaziland.
Johannesburg: BirdLife South Africa.
MuMIn: Multi-model inference. R package version 1.12.1. Available at http://CRAN.R-project.org/package=MuMIn
- K Barton
Black-rumped Buttonquail (Aves: Turnicidae) nest records and notes from KwaZulu-Natal
- Mb Christian
Hottentot Buttonquail
- Wrj Dean
Dean WRJ. 2005. Hottentot Buttonquail. In: Hockey PAR, Dean WRJ,
Ryan PG (eds), Roberts birds of southern Africa (7th edn): Cape
Town: Trustees of the John Voelcker Bird Book Fund. pp 162-164.
Buttonquails (Turnicidae)
- S Debus
- A Bonan
- J Del Hoyo
- A Elliott
- J Sargatal
- D A Christie
Debus S, Bonan A. 2016. Buttonquails (Turnicidae). In: del Hoyo J,
Elliott A, Sargatal J, Christie DA, de Juana E (eds), Handbook of
the birds of the world alive. Barcelona: Lynx Edicions. Available
at http://www.hbw.com/node/52225 [accessed 30 June 2016].
Fynbos enigma - Hottentot Buttonquail in the Kouga Mountains
- A T Lee
Lee AT. 2013. Fynbos enigma -Hottentot Buttonquail in the Kouga
Mountains. African Birdlife 1: 20-22.
dplyr: a grammar of data manipulation. R package version 0.4.1. Available at http://CRAN.R-project.org/package=dplyr
- H Wickham
- R Francois
Blackrumped Buttonquail at Betty's Bay
- J Blackshaw
- N Blackshaw
Blackshaw J, Blackshaw N. 1998. Blackrumped Buttonquail at
Betty's Bay. Promerops 234: 12.
Fynbos: South Africa’s unique floral kingdom. Cape Town: University of Cape Town
- R Cowling
gam: Generalized additive models. R package version 0.98
- T Hastie
Hastie T. 2013. gam: Generalized additive models. R package
version 0.98. Available at https://cran.r-project.org/web/packages/
gam/ [accessed 10 March 2017].
The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. Pretoria: South African National Biodiversity Institute
- L Mucina
- Mc Rutherford
Is the hottentot buttonquail really endangered?
- P Ryan
- P Hockey
Ryan P, Hockey P. 1995. Is the hottentot buttonquail really
endangered? Ostrich 66: 92-93.
Fynbos: South Africa's unique floral kingdom
- R Cowling
Cowling R. 1995. Fynbos: South Africa's unique floral kingdom.
Cape Town: University of Cape Town.
The vegetation of South Africa
Mucina L, Rutherford MC (eds). 2006. The vegetation of South
Africa, Lesotho and Swaziland. Strelitzia 19. Pretoria: South
African National Biodiversity Institute.
Blackrumped Buttonquail at Betty’s Bay. Promerops 234: 12
- J Blackshaw
- N Blackshaw