Sample Of Squares Research Articles

Population and distribution change of Eurasian Woodcocks Scolopax rusticola breeding in the UK: results of the 2023 Breeding Woodcock Survey

ABSTRACT Capsule The UK breeding population estimate comprised 50,750 male Eurasian Woodcocks (95% CI: 42,935–59,251) in Britain and 937 males (95% CI: 274–1714) in Northern Ireland. The British population has continued to decline since 2013. Aim To produce UK, British and regional estimates of breeding population size for Eurasian Woodcocks, and to assess the population change since 2003. Methods The 2023 Breeding Woodcock Survey enlisted volunteer surveyors to count birds across a stratified sample of 1230 squares in England, Scotland, Wales, and Northern Ireland. The established ‘roding count’ methodology consists of up to three dusk visits, each lasting 75 min, during May and/or June. The results were used to calculate presence and mean density across 48 strata based on wooded area and regions, and extrapolated to produce regional and national estimates of population size. Results The population in Britain in 2023 was estimated at 50,750 male Woodcocks (95 CI: 42,935–59,251), representing an 8% decline since 2013, and a 35% decline since 2003. Despite small population increases in Wales and England since 2013, the continuing decline was driven by a 49.5% reduction in the population estimate for North Scotland. In 2023, Northern Ireland’s breeding population of Eurasian Woodcocks was estimated at 937 males (95% CI: 274–1714), which is the first estimate produced using this species-specific method. Conclusion Nationally, populations of Eurasian Woodcocks continue to decline, but the 2013–2023 declines were not as severe as those recorded between 2003 and 2013. The diverging population trends between North Scotland and the rest of Britain raise questions regarding regional variation in habitat suitability/availability and factors influencing overwinter survival. Recommendations are made for future versions of the Breeding Woodcock Survey regarding the composition of the random sample of squares, the treatment of incomplete data, and the sampling of non-woodland habitat.

Integrated ecological monitoring in Wales: the Glastir Monitoring and Evaluation Programme field survey

Abstract. The Glastir Monitoring and Evaluation Programme (GMEP) ran from 2013 until 2016 and was probably the most comprehensive programme of ecological study ever undertaken at a national scale in Wales. The programme aimed to (1) set up an evaluation of the environmental effects of the Glastir agri-environment scheme and (2) quantify environmental status and trends across the wider countryside of Wales. The focus was on outcomes for climate change mitigation, biodiversity, soil and water quality, woodland expansion, and cultural landscapes. As such, GMEP included a large field-survey component, collecting data on a range of elements including vegetation, land cover and use, soils, freshwaters, birds, and insect pollinators from up to three-hundred 1 km survey squares throughout Wales. The field survey capitalised upon the UK Centre for Ecology & Hydrology (UKCEH) Countryside Survey of Great Britain, which has provided an extensive set of repeated, standardised ecological measurements since 1978. The design of both GMEP and the UKCEH Countryside Survey involved stratified-random sampling of squares from a 1 km grid, ensuring proportional representation from land classes with distinct climate, geology and physical geography. Data were collected from different land cover types and landscape features by trained professional surveyors, following standardised and published protocols. Thus, GMEP was designed so that surveys could be repeated at regular intervals to monitor the Welsh environment, including the impacts of agri-environment interventions. One such repeat survey is scheduled for 2021 under the Environment and Rural Affairs Monitoring & Modelling Programme (ERAMMP). Data from GMEP have been used to address many applied policy questions, but there is major potential for further analyses. The precise locations of data collection are not publicly available, largely for reasons of landowner confidentiality. However, the wide variety of available datasets can be (1) analysed at coarse spatial resolutions and (2) linked to each other based on square-level and plot-level identifiers, allowing exploration of relationships, trade-offs and synergies. This paper describes the key sets of raw data arising from the field survey at co-located sites (2013 to 2016). Data from each of these survey elements are available with the following digital object identifiers (DOIs): Landscape features (Maskell et al., 2020a–c), https://doi.org/10.5285/82c63533-529e-47b9-8e78-51b27028cc7f, https://doi.org/10.5285/9f8d9cc6-b552-4c8b-af09-e92743cdd3de, https://doi.org/10.5285/f481c6bf-5774-4df8-8776-c4d7bf059d40; Vegetation plots (Smart et al., 2020), https://doi.org/10.5285/71d3619c-4439-4c9e-84dc-3ca873d7f5cc; Topsoil physico-chemical properties (Robinson et al., 2019), https://doi.org/10.5285/0fa51dc6-1537-4ad6-9d06-e476c137ed09; Topsoil meso-fauna (Keith et al., 2019), https://doi.org/10.5285/1c5cf317-2f03-4fef-b060-9eccbb4d9c21; Topsoil particle size distribution (Lebron et al., 2020), https://doi.org/10.5285/d6c3cc3c-a7b7-48b2-9e61-d07454639656; Headwater stream quality metrics (Scarlett et al., 2020a), https://doi.org/10.5285/e305fa80-3d38-4576-beef-f6546fad5d45; Pond quality metrics (Scarlett et al., 2020b), https://doi.org/10.5285/687b38d3-2278-41a0-9317-2c7595d6b882; Insect pollinator and flower data (Botham et al., 2020), https://doi.org/10.5285/3c8f4e46-bf6c-4ea1-9340-571fede26ee8; and Bird counts (Siriwardena et al., 2020), https://doi.org/10.5285/31da0a94-62be-47b3-b76e-4bdef3037360.

KEANEKARAGAMAN JENIS TUMBUHAN BAWAH TANAMAN AKASIA (Acacia mangium Willd) DI BUKIT PENGHIJAUAN MANDOR KABUPATEN LANDAK

Acacia mangium plantations in Bukit Penghijauan has grown by various species of understoreys. This study aims are to examine uderstoreys diversity and determine the amount of species and dominant of understoreys that’s growing under Acacia stands in Bukit Penghijauan Mandor Landak District. The study used a survey method with a systematic sampling of squares. Laying of plots was carried out by purposive sampling in area where are acacia plants. The size of plot is 10 m x 10 m, devided in to 25 sample plots of size 2 m x 2 m. Prymary data on taken involve species name, amount of individuals each species and herbarium specimens as identification device. The study result swowed that understoreys that be discovered under acacia stands in Bukit Penghijauan Mandor Landak District as much 21 species. The domination that species is paku resam (Gleichenia linearis Burm Clarke), rumput bede (Paspalum conjugatum Berg) and akar rambat (Psychotria sarmentosoides).Keywords : Bukit penghijauan, Species diversity, Understoreys.

MONITORING OF AGRICULTURAL LANDSCAPE IN NORWAY

Abstract. An overall societal aim is to ensure a sustainable use and management of agricultural landscapes. This requires continuous delivery of reliable and up-to-date information to decision-makers. To be able to deliver this information, a monitoring program for agricultural landscapes was initiated in Norway 13 years ago. The program documents and reports on land use / land cover changes from data captured through interpretation of true colour aerial photos using stereo instruments. The monitoring programme is based on a sample of 1000 squares of 1 × 1 km and the entire sample of squares is photographed over a five-year period. Each square is then mapped repeatedly every fifth year to record changes. Aerial photo interpretation is based on a custom classification system which is built up hierarchically, with three levels. The first level comprises seven land type classes: Agricultural land, Bare ground, Semi-natural open vegetation, Unforested wetland vegetation, Forest, Urban areas and Water. These land classes are further divided into 24 land types at level two, and approximately 100 land types at level 3. In addition to land type units we map both line elements like stone fences and point elements like buildings and solitary threes. By use of indicators that describe status and change focusing on themes of particular policy interest, we can report on whether policy aims are being fulfilled or not. Four indicator themes have been in focus hitherto: landscape spatial structure, biological diversity, cultural heritage and accessibility. Our data is stored in databases and most of the data quality check/structure process and analyses are now being made in open source software like PostGIS and PostSQL. To assess the accuracy of the photo-interpretation, ground truthing is carried out on 10 % of the squares. The results of this operation document the benefits of having access to photos of the same area from two different years. The program is designed first and foremost to provide reliable statistics at a national level but the aim is also to report at regional levels – for example for counties or for agricultural landscape regions. The national coverage and application of standardized methods enable frequent updating. This method is cost effective and enables us to quantify changes in landscape qualities as well as adapting the programme to take account of e.g. new findings on relevant indicators.

Estimating the extent and change in Broad Habitats in Great Britain

A stratified random sample of kilometre squares in Great Britain was visited and completely mapped using four areal themes (agriculture and semi-natural vegetation, forestry, physiography and buildings and communications). The maps were digitised and the attribute information recorded to produce an electronic database. Information was summarised by square and then bootstrap re-sampling techniques were used to produce national estimates with statistical confidence intervals. The results for 1998 showed the terrestrial Broad Habitats had a range in extent covering two orders of magnitude from Montane (49 000 ha) to Improved Grassland (5482 000 ha). Just under half of Britain is covered by agricultural Broad Habitats, about 12% by woodland and just under 10% by Urban Habitats. The remaining quarter of the land area is covered by semi-natural Broad Habitats. By revisiting the same sample of squares previously visited in 1990, changes in the quantity and quality of the Broad Habitats have been determined. Significant increases in area have occurred in the Broadleaved, Mixed and Yew Woodland and Built Up and Gardens. The largest areal reduction was in Acid Grassland although that was in part balanced by a gain in Fen, Marsh and Swamp. The most significant ecological loss was in the area of Calcareous Grassland. The consequences of having different sample sizes for the different years are discussed.

Progressive bias in species status is symptomatic of fine-grained mapping units subject to repeated sampling

Atlas maps of butterflies invariably fail to distinguish the status of records, that is, whether they are observations of breeding populations or vagrant individuals. Yet, for conservation purposes, it is clearly important to know whether records relate to breeding populations in suitable habitats or not. The high mobility of butterfly adults carries two expectations. First, vagrants will frequently be recorded within grid squares, particularly when mapping is fine grained. Second, the frequency of vagrants is likely to be higher in mapping units comprising biotopes with few butterfly habitats, than in those rich in butterfly habitats, if only because there is a greater regional pool of potential vagrants for biotopes depleted in butterfly habitats. It follows that with repeated sampling of squares or biotopes differences in species breeding status will be cumulative between those rich and poor in butterfly habitats. In this paper, these predictions have been tested using data from 30, 1 ha grid squares on Alderley Edge Site of Special Scientific Interest (SSSI) (UK), half of which are in woodland (few butterfly habitats) and half with open habitats (non-woodland; rich in butterfly habitats). Butterflies have been recorded during 38 visits over 4 years. Within squares, vagrants have been distinguished from breeding species on the basis of the presence of larval hostplants and other suitable resources for seasonal maintenance. Owing to the occurrence of vagrants, number of breeding species was found to be significantly fewer than total species in mapping units. Vagrants were found to be significantly more abundant in woodland squares, which contain few species larval hostplants, than in squares dominated by open biotopes with many species larval hostplants. Repeated sampling resulted in a cumulative increase in the frequency of vagrant species. Furthermore, the relative frequency of vagrants increased at a greater rate in woodland squares compared to non-woodland squares. Suggestions are made as to how recording for atlases may be improved.

Loss rates of butterfly species with urban development. A test of atlas data and sampling artefacts at a fine scale

Data for the United Kingdom (UK) Manchester Butterfly Atlas produced conflicting species loss rates for increased urban development. In particular, a very low rate of loss was recorded (0.19 species for every 10% increase in urban cover) for the Mersey Valley mapped at a high resolution of 1 ha units. It was suggested that sampling artefacts (uneven recording) or failure to distinguish vagrant individuals from breeding populations cause this. Herein, results are reported for 30 sample squares, within the Mersey Valley, surveyed uniformly throughout 1999. It is shown that loss rates are as high as areas mapped at lower resolution over wider areas (0.67–0.68 species for every 10% increase in urban cover) and that increasingly stringent definitions of urban cover result in higher loss rates. Comparison with the data from the Atlas, but for the same 30 sample squares, indicate that the low rates at a fine scale for the complete Atlas data are more likely to be caused by uneven recording than from failure to record species status. However, progressive sampling of squares, despite uniform recording, will inevitably cause a reduction in loss rates of total species for increases in urban development.

ITE Merlewood Land Classification of Great Britain

Abstract. The Institute of Terrestrial Ecology (ITE) has classified the 1 km squares in Great Britain (GB) into thirty‐two environmental strata, termed land classes, as a basis for ecological survey. The classes have been used in biogeographical studies of the distribution of individual species and species assemblages. The concept behind the technique is that there is an association between the environmental character of land and ecological parameters. The initial classification was based on a sample of squares drawn from a regular grid. The data for the 12121 km squares classified were drawn from published maps; the number of squares was limited by the available computing power. Subsequently the availability of more powerful computers and the need to improve geographical definition have led to the allocation of every 1 km square to its appropriate class. This paper has been written to summarise the principles involved in the development of the system and indicate the range of projects for which it has been used. The extension of the classification from a sample to the complete coverage of GB revealed the importance of the structure and style of data used to produce the classification. The significance of these conclusions for future work is discussed, with particular reference to automated methods of data capture.

An Autologistic Model for the Spatial Distribution of Wildlife

1. A new method for estimating the geographical distribution of plant and animal species from incomplete field survey data is developed. 2. Wildlife surveys are often conducted by dividing a study region into a regular grid and collecting data on abundance or on presence/absence from some or all of the squares in the grid. Generalized linear models (GLMs) can be used to model the spatial distribution of a species within such a grid by relating the response variable (abundance or presence/absence) to spatially referenced covariates. 3. Such models ignore or at best indirectly model dependence on unmeasured covariates, and the intrinsic spatial autocorrelation arising for example in gregarious populations. 4. We describe a procedure for use with presence/absence data in which spatial autocorrelation is modelled explicitly. We achieve this by extending a logistic model to include an extra covariate which is derived from the responses at neighbouring squares. The extended model is known as an autologistic model. 5. To allow fitting of the autologistic model when only a random sample of squares is surveyed, we use the Gibbs sampler to predict presence/absence at unsurveyed squares. 6. We compare the autologistic model with the ordinary logistic model using red deer census data. Both models are fitted to a subsample of 20% of the data and results are compared with the 'true' abundance and spatial distribution indicated by the full census. We conclude that the autologistic model is superior for estimating the spatial distribution of the deer, whereas the ordinary logistic model yields more precise estimates of the overall number of squares occupied by deer at the time of the survey.

Influence of Temperature on Abscission of Cotton Squares Infested with Boll Weevil Eggs13

The mean time from egg deposition of the boll weevil, Anthonomus grandis Boheman, until square abscission at 5 selected temperatures ranged from 5.8 to 18.6 days at 34 to 18°C respectively. At 26°C ca. ½ of the squares remained on the plants longer than 7 days, suggesting that weekly sampling of squares as a basis for treatment decisions may be reflecting accrued in addition to current damage.