Occurrence Of Most Species Research Articles

Seasonal variation of birds on a feeding site in a suburban area near Oslo, Norway

The birds visiting a feeding site near a villa in a suburban, residential area in Bærum municipality, west of Oslo, were monitored daily during 1997 - 99, and at irregular intervals during 1993 - 96. Sixteen species had a frequency of more than one week during 1997 - 99. The most common species were: Magpie, Great Tit, Blue Tit, Greenfinch, and Tree Sparrow, all of which occurred during most of the year. There was a clear seasonal pattern in the occurrence of most species. Three species, Siskin, Redpoll, and Brambling, were irregular and occasionally present in relatively large numbers. Invasions occurred especially during cold spells. Among migrant birds, the Blackbird was regularly present during winter. The Robin overwintered irregularly, especially in mild winters.

Directional succession and species-specific patterns observed in repeat study of vascular plants at three glacier foreland chronosequences in the Canadian High Arctic

This paper presents the first repeat study of glacier foreland chronosequences conducted in the Canadian High Arctic. Vascular plant species at three forelands on Ellesmere Island, Nunavut first surveyed in 1995 were resurveyed 21 years later to (1) test the original hypothesis that succession on these forelands was directional, and (2) investigate the use of the chronosequence method in High Arctic succession studies. Forelands were surveyed using percent cover estimates or presence/absence counts. Indicator species analysis and rates of change were used to quantify shifts. Total plant cover and species richness increased on younger terrain. Rates of peak cover and first appearance advance varied greatly between species and forelands, but were generally faster for graminoid and forb species than shrub species. We observed a pattern of directional succession at all three forelands, supporting the original hypothesis. However, species-specific patterns and rates of change acted to create assemblages that differed between 1995 and 2016, different successional trajectories were observed between the three forelands, and the first occurrence of most species was further from the glacier margin in 2016 compared to 1995. These results demonstrate the importance of repeat studies over time and replication over space to confirm observations in chronosequence studies.

Limno-Terrestrial Tardigrada of Sub-Antarctic Islands—An Annotated Review

Research on the limno-terrestrial Tardigrada fauna of the Sub-Antarctic zone began almost 120 years ago. Here we present an overview of the literature data on the presence of tardigrades on sub-Antarctic islands, including the substrates on which they have been found. From 32 published sources, we found original data on the occurrence of 49 currently valid species on six sub-Antarctic islands/island groups. Of these, 9 species (18%) were originally described from this zone, another 13 species (26%) were described from Continental or Maritime Antarctica, almost half of these species (22 species—45%) were originally described from European localities, and the remaining 5 species (10%) were originally described from South America, Africa, or Australia. The validity of the records of individual species is discussed. We consider the presence of 29 species in the Sub-Antarctic to be doubtful. We ascertained a total of 90 combinations of species and islands or island groups. More than half (64%) of these will require confirmation in the future because we currently consider them doubtful. We can conclude that the tardigrade fauna of the sub-Antarctic islands is only very superficially known, and the occurrence of most species in this zone must be verified.

Co-occurrence patterns and community assembly mechanisms of benthic foraminiferal communities in South Chinese bays

Benthic foraminifera are among the most important components of marine benthic communities and can provide valuable information about the structure and activity of those communities. The distribution and diversity of benthic foraminifera have been well documented, but their co-occurrence patterns and community assembly processes have rarely been elucidated. To fill this gap, we used network analysis and null/neutral model approaches to benthic foraminiferal communities in five bays in South China to evaluate the influences of environmental factors and interspecies interactions on species co-occurrence and the relative importance of deterministic and stochastic processes in shaping community structure, respectively. The spatial heterogeneity of foraminiferal communities across bays was characterized by nonmetric multidimensional scaling analysis. Variation partitioning analysis showed that heavy metals (Cr, Co, Cu, As, Sb, and Hg) were the most important factor influencing community structure, while less importance was attributed to organic matter and grain sizes, which was likely due to the low TOC contents and small variations in TOC and grain size across sites. Network analysis showed that closely related species tended to co-occur with each other, which may be mediated by environmental filtering. The network was divided into three distinct clusters: one cluster consisted of miliolid, and two were dominated by rotaliids, each of which represented a special niche according to the habitat preference of the dominant taxa. The structure of the network was highly informative, as illustrated by the fact that the observed structure was denser than that of randomly constructed networks with the same size or the same degree sequence. The frequency of occurrence of most species (70%) met neutral model expectations, indicating that neutral processes were important for the assembly of benthic foraminiferal communities. However, PER-SIMPER analysis revealed that niche-assembly processes were more important than dispersal-assembly processes in shaping species abundance. Overall, this study provides the first insight into the mechanisms maintaining the community structure and diversity of benthic foraminifera.

Does the colors of light matter? Testing different light color in nocturnal underwater visual censuses

Most methods for assessing reef fish assemblages at night require artificial light, but the use of different colors of light may influence the results. We used data from 135 underwater visual censuses (UVCs) performed with different colors of light (red, blue and white) to evaluate the structure of fish assemblages on subtropical rocky reefs along three depth intervals. We did not detect any effect of the color of light on total density or fish species richness per transect, nor on the structure of the entire assemblage. However, the density of some of the most abundant species varied according to the color used. Red light showed the highest values of frequency of occurrence for most species, while the white light resulted in decreased abundance of some fish species. Our results emphasize the importance of choosing the color of light depending on the type of studies to be conducted. This will depend on the objectives of the research (e.g. inventory, behavior or community dynamics) and the target fish fauna (e.g. mobile or sedentary).

Diversity of Diptera species associated with pig carcasses in a Brazilian city exposed to high rates of homicide

Cities in northeastern Brazil experience extreme rates of unsolved homicides, a situation that stimulates innovative procedures in the police work, such as forensic entomology. We surveyed necrophagous insects associated with carrion in a city exposed to high rates of homicides in Northeastern Brazil. The experiments were carried out in a rainforest fragment located in Recife, State of Pernambuco. Two pig carcasses were used as models, one in the dry and the other in the rainy season. The collection of adults was performed daily until the complete skeletonization of the carcasses. At least 32 Diptera species from the families Calliphoridae, Muscidae, Sarcophagidae, Fanniidae, Phoridae, Anthomyiidae, Piophilidae, and Stratiomyidae were registered, some of which have been previously documented on cadavers. A high richness of Diptera species was registered in all stages of decomposition. A strong overlap in the occurrence of most species was observed, which invalidates a defined entomological succession on the carcasses. Two species stood out in terms of abundance: Ophyra chalcogaster (Muscidae) and Chrysomya albiceps (Calliphoridae). The ubiquity of Hemilucilia semidiaphana (Calliphoridae) seems to confirm its preference for forest fragments exposed to low anthropogenic action. Our data contribute to expand the knowledge on the geographical distribution of forensically relevant species in the region and confirm the rapid dissemination of invasive Chrysomya species in forested areas.

Vulnerability of mammal communities to the combined impacts of anthropic land-use and climate change in the Himalayan conservation landscape of Bhutan

Human land-use and climate change drive biodiversity loss, precipitating the extinction crisis. The fragility of the Himalayas makes species in this landscape vulnerable to land-use and climate change. We aim to quantify the response of terrestrial mammal community to land-use and climate scenarios in the Bhutan Himalaya. Using large-scale camera-trap dataset, we examine the effects of anthropic land-use and climate variables on the terrestrial mammal assemblage using Bayesian multi-species occupancy model. Most of the terrestrial mammals in our sample displayed a strong negative relationship with anthropic land-use variables (agriculture, roads and settlement). Further, the occurrence of most species decreased with likely projections for climate variables, illustrating threats to conservation if the current trend in global warming continues. Notably, we found that biodiversity conservation in this landscape can be achieved by protecting extensive forest cover. Our findings emphasize the importance of reconciling land-use management and mammal conservation in the face of climate change and provide vital information which can be used to optimize future conservation and development plans.

When a freshwater invader meets the estuary: the peacock bass and fish assemblages in the São João River, Brazil

Peacock basses (Cichla spp.) are native to the Amazon basin but introduced to different parts of the world. Almost thirty years ago, Cichla kelberi was introduced in an impoundment of the Sao Joao River, a coastal system in southeastern Brazil. Recently, this cichlid invaded the estuarine section of the basin. This study aims to analyze spatial and temporal variations in catch of C. kelberi and fish assemblage structure along the estuarine stretch of this river and how abiotic variables affect their distribution. Sampling was performed in four segments downstream of the dam. Principal component analysis revealed that abiotic variables displayed temporal and spatial variation, in part due to the salinity gradient, that were more pronounced in the dry season. Cichla kelberi occurred in all segments, but mainly in shallow and vegetated habitats of the middle course and barely in the most downstream. Eighty-one fish species were recorded, nine of which were non-native, representing 33.4% of total catch. A redundancy analysis indicated that the fish assemblages showed marked spatial variation, mostly related to the salinity gradient. The lowermost segment of the river was dominated by marine species, the only locality where non-native species summed less than 40% of the catches. In the upstream segments, higher oxygen levels and lower temperatures influenced the occurrence of most species. Higher salinity of the estuary seems to limit the spread of C. kelberi, but the invader may reach adjacent basins in years of exceptional floods. The eurihalinity and piscivory of C. kelberi partly explain its invasive success.

The effects of shrub encroachment on bird occupancy vary with land use in an African savanna

AbstractLand‐cover and land‐use change are major drivers of global biodiversity loss. Savannas are experiencing shrub encroachment and land‐use changes that affect animal communities, yet how the effects of shrub encroachment vary with land use remains unclear. We also need to determine which species traits explain the effects of shrub encroachment and land‐use changes to identify potential drivers of community change and predict species' responses to conservation efforts. We sampled birds across gradients of shrub encroachment and land use (protected savanna, pastures, homestead lands, and sugarcane) in the lowveld savanna of Eswatini to: (1) test for the effects of shrub encroachment, land‐use change, and their potential synergies on the occurrence of 48 species of birds; and (2) determine which species traits (those associated with nesting, foraging, or vulnerability to predation) explained species' associations with shrub encroachment and land‐use change. We used Bayesian multispecies occupancy models to account for imperfect detection, interpret species responses, and understand the effects of species traits. We found evidence for community‐wide synergies between shrub encroachment and land‐use effects on birds that varied with species' diets. Agricultural intensification had negative effects on the occurrence of most species examined, while shrub cover typically had positive effects which were stronger in pastures and homestead lands than in protected areas. The negative effects of land‐use change were greatest for insectivores and cavity nesters, whereas insectivore occurrence increased with shrub cover, collectively indicating that nesting and foraging traits best explained species responses to land‐use and land‐cover change in the region. Our results suggest that shrub cover management for bird conservation should vary with land use: shrubs could be thinned in protected areas without reducing bird occupancy but shrubs in homesteads should be retained.

Evaluation and potential use of native forest species in the recovery of a legal reserve in the Western Amazon

The Brazilian Amazon, which has been heavily devastated by exploratory processes and human occupation, has great value in terms of forest resources. As such, the aim of this study was to evaluate the potential use of native forest species to constitute productive agroforestry systems that can be set up in areas of legal reserve. A floristic/phytosociological survey was carried out of tree individuals with a diameter at breast height (DBH) ≥10 cm in 12 plots of 50 x 100 m (0.5 ha). From the data, species with a density of greater than three trees ha-1 were selected, and evaluated for use and ecological group. A total of 180 species distributed in 40 botanical families were identified, of which only 23 species presented an absolute density (AD) ≥3 trees ha-1, indicating that the occurrence of most species in the area is rare. Species such as Copaifera multijuga, Dinizia excelsa, Peltogyne paniculata, Tachigali chrysophylla, Dipteryx odorata, Bertholletia excelsa and Hevea brasiliensis are used commercially and may be indicated for production systems. As a result, native Amazonian forest species have great potential for use in recovery programs, promoting the recovery of local biodiversity and the development of small rural properties. However, it is necessary to invest in research and the development of public policy to support such initiatives.

The effects of water quality on back-reef sponge survival and distribution in the Florida Keys, Florida (USA)

For decades, water quality in Florida Bay and the shallow, back-reef areas of large portions of the Florida Keys (Florida, USA) have varied dramatically as a consequence of climatic conditions and water management strategies in the adjacent freshwater marshes of the Everglades. The resulting fluctuations in water quality have led to die-offs of seagrass and sponges in hard-bottom habitats, transforming the ecosystem. In this study, we examined the implications of water quality on sponge community structure in two ways. First, in laboratory experiments we tested the tolerance of five prominent sponge species to salinities ranging from 15 psu to 45 psu at typical summer and winter temperatures. We then compared sponge distributions at 32 sites in the Florida Keys with regional patterns in water quality. Our experiments showed that during the summer the loggerhead sponge (Speciospongia vesparium) and glove sponge (Spongia cheiris) were the most tolerant of sustained changes in salinity, but most species died at higher rates at salinities other than 35 psu. Salinity-associated mortality declined in the winter, but was again higher at salinities <35 psu. A pulsed change in salinity at summer temperatures yielded idiosyncratic results depending on the species. Analysis of the field data showed that some species such as Ircinia variablis and Cinachyrella alloclada grow in most environments, whereas the occurrence of most species declines when salinity is variable and at high nutrient concentrations. These results provide a more detailed picture of the species-specific environmental tolerance of several shallow-water Caribbean sponges, and suggest that changes in environmental conditions are likely to significantly impact their distribution and species composition with potentially drastic impacts on ecosystem function.

Cave features, seasonality and subterranean distribution of non-obligate cave dwellers.

Seasonality impacts species distributions through changes of the environmental conditions that affect the presence of individuals at a given place. Although the dynamics of cave microclimates are well known, only a few studies have evaluated the effects of such dynamics on non-strictly cave species. Here we assessed if species exploiting subterranean environments show changes in habitat occupation related to seasonal variation of cave microclimates. We surveyed 16 caves in central Italy every month for one year. Caves were subdivided into longitudinal sectors of three meters. In each sector we measured cave morphology and microclimatic features, assessed the occurrence of eight non-troglobitic taxa (orthopterans, spiders, gastropods and amphibians), and related species distribution to environmental features and sampling periods. The occurrence of most species was related to both cave morphology and microclimatic features. The survey month was the major factor determining the presence of species in cave sectors, indicating that cave-dwelling taxa show strong seasonality in activity and distribution. For multiple species, we detected interactions between sampling period and microclimatic features, suggesting that species may associate with different microhabitats throughout the year. The richest communities were found in sites with specific microclimates (i.e., high humidity, warm temperature and low light) but seasonality for species richness was strong as well, stressing the complexity of interactions between outdoor and subterranean environments.

Oil palm plantations fail to support mammal diversity.

Agricultural expansion is the largest threat to global biodiversity. In particular, the rapid spread of tree plantations is a primary driver of deforestation in hyperdiverse tropical regions. Plantations tend to support considerably lower biodiversity than native forest, but it remains unclear whether plantation traits affect their ability to sustain native wildlife populations, particularly for threatened taxa. If animal diversity varies across plantations with different characteristics, these traits could be manipulated to make plantations more "wildlife friendly." The degree to which plantations create edge effects that degrade habitat quality in adjacent forest also remains unclear, limiting our ability to predict wildlife persistence in mixed-use landscapes. We used systematic camera trapping to investigate mammal occurrence and diversity in oil palm plantations and adjacent forest in Sabah, Malaysian Borneo. Mammals within plantations were largely constrained to locations near native forest; the occurrence of most species and overall species richness declined abruptly with decreasing forest proximity from an estimated 14 species at the forest ecotone to -1 species 2 km into the plantation. Neither tree height nor canopy cover within plantations strongly affected mammal diversity or occurrence, suggesting that manipulating tree spacing or planting cycles might not make plantations more wildlife friendly. Plantations did not appear to generate strong edge effects; mammal richness within forest remained high and consistent up to the plantation ecotone. Our results suggest that land-sparing strategies, as opposed to efforts to make plantations more wildlife-friendly, are required for regional wildlife conservation in biodiverse tropical ecosystems.

Vertical distribution of macrolichens on the birches near Petropavlovsk-Kamchatskii

Species composition and frequency of occurrence of macrolichens on Betula ermanii and B. platyphylla are studied. Frequency of occurrence of most species of these lichens is less than 10%. Frequency of occurrence of some species on different trunk levels was considerably different. Usually, frequency of occurrence of macrolichens on B. ermanii was higher than on B. platyphylla. Distribution of ten dominant species on different trunk height was studied applying one-factored ANOVA. Cladonia coniocraea, Parmelopsis sp., and Vulpicida pinastri occur preferably on trunk bottoms. Cetraria sepincola was homogeneously on trunks of both birch species. Hypogymnia physodes, Parmelia squarrosa, and P. sulcata are definitely confined to the middle part of trunks and branches only on B. ermanii. On B. platyphylla, these species are homogeneously distributed.

Sediment-benthos relationships as a tool to assist in conservation practices in a coastal lagoon subjected to sediment change

This study explores the relation between sediment composition and intertidal macrobenthos populations in the Zwin nature reserve (Belgium and The Netherlands), a tidal lagoon that is included in the Ramsar list of wetlands of international importance and has been designated as Natura 2000 area, among others due to its function as wintering habitat for shorebirds that feed upon macrobenthic invertebrates. Species response models show highest biomass of these prey species in organically enriched cohesive sediments and a distinct decline in probability of occurrence for most species in coarse sediments. Further, the biomass of macrobenthos declined between 2003 and 2010 in the extensive low intertidal inlet channel concurrent with the coarsening of the sediment over time in this hydrodynamically stressed habitat. In contrast, macrobenthos biomass increased in a sheltered shallow intertidal habitat that acted as a catchment area for finer sediments, therefore facilitating the succession towards a higher elevated habitat with salt marsh vegetation establishment. Hence, spatio-temporal sediment dynamics decreased site quality for intertidal predators due to a reduction in feeding areas over time, and a change in physical sediment properties that alter the macrobenthos species occurrence and population biomass. This study thus illustrates that sediment transport dynamics may affect the functioning of coastal shallow soft-sediment habitats, like coastal lagoons. The presented macrobenthos species response models provide a tool to assist in management actions that enable the conservation of cohesive low intertidal habitats that provide a high food supply to shorebirds, fish and macrocrustaceans.

A decade of change in the saproxylic beetle fauna of eucalypt logs in the Warra long-term log-decay experiment, Tasmania. 1. Description of the fauna and seasonality patterns

The first decade of sequential and cyclical sampling of saproxylic beetles by means of eclector traps on 12 freshly-felled Eucalyptus obliqua logs at Warra, Tasmania has allowed documentation of a taxonomically and ecologically diverse fauna present in such logs in their early decompositional state. About half of all species are apparently undescribed—a much higher proportion than in most temperate regions. The distribution of individuals among species is typically skewed, with most species being rare and few being common. Neither obligately nor facultatively saproxylic beetles dominate the fauna, but predators predominate over other larval feeding guilds, and—in accordance with ecological theory for early successional habitats—winged species predominate over functionally flightless species. There is some suggestion that trophic structure changed over the period of the study, with the proportion of functionally flightless species increasing. The fauna shows strong seasonality. While the summer months represent the peak of occurrence for most species (in keeping with the cool-temperate climate), every month has its own particular complement of species, such that a strong seasonal cycle in assemblage composition is apparent throughout the year. The timings of emergence peaks vary among the years represented in this study by up to 2 months, with the year of latest emergence corresponding to that with the lowest mean annual maximum temperature; no signature of climate change is evident in the data-set.

Size structure and dynamics of some woody perennials along elevation gradient in Wadi Gimal, Red Sea coast of Egypt

The population structure of 10 common woody perennials was investigated in terms of size distribution, height, diameter and density in Wadi Gimal along the Red Sea coast of Egypt. It was attempted to assess the effect of elevation on the size, distribution and density of the studied species. These species are: five trees ( Acacia tortilis subsp. raddiana, Acacia tortilis subsp. tortilis, Balanites aegyptiaca, Tamarix aphylla, and Tamarix nilotica), two shrubs ( Leptadenia pyrotechnica and Nitraria retusa) and three shrublets ( Pulicaria undulata, Zilla spinosa, and Zygophyllum coccineum). The size estimations were then used to classify population into six size classes: 20–80 cm for shrublets, 100–500 cm for shrubs, and 2–10 m for trees. The absolute and relative frequency of individuals and mean height, diameter and height to diameter ratio per individual in each size class were determined. Density of occurrence of most species, except B. aegyptiaca, decreased as elevation increased. The height-to-diameter ratio was less than unity for most of the recorded species except T. nilotica. Several forms – including, positively and negatively skewed, inverse J-shaped, bell shaped and more or less J-shaped distributions – were recognized along the different elevations. The size structure of some species was positively related with soil variables, such as T. nilotica with sulphate, while some others were negatively significant related to the substrate characteristics, such as Z. spinosa with salinity.

Size Structure and Dynamics of Some Woody Perennials along Elevation Gradient in Wadi Gimal, Red Sea Coast of Egypt

Abstract The population structure of 10 common woody perennials was investigated in terms of size distribution, height, diameter and density in Wadi Gimal along the Red Sea coast of Egypt. It was attempted to assess the effect of elevation on the size, distribution and density of the studied species. These species are: five trees (Acacia tortilis subsp. raddiana, Acacia tortilis subsp. tortilis, Balanites aegyptiaca, Tamarix aphylla, and Tamarix nilotica), two shrubs (Leptadenia pyrotechnica and Nitraria retusa) and three shrublets (Pulicaria undulata, Zilla spinosa, and Zygophyllum coccineum). The size estimations were then used to classify population into six size classes: 20–80 cm for shrublets, 100–500 cm for shrubs, and 2–10 m for trees. The absolute and relative frequency of individuals and mean height, diameter and height to diameter ratio per individual in each size class were determined. Density of occurrence of most species, except B. aegyptiaca, decreased as elevation increased. The height-to-diameter ratio was less than unity for most of the recorded species except T. nilotica. Several forms – including, positively and negatively skewed, inverse J-shaped, bell shaped and more or less J-shaped distributions – were recognized along the different elevations. The size structure of some species was positively related with soil variables, such as T. nilotica with sulphate, while some others were negatively significant related to the substrate characteristics, such as Z. spinosa with salinity.

Modelling the impacts of flow regulation on fish distributions in naturally intermittent lowland streams: an approach for predicting restoration responses

Summary1. Understanding the relationships between flow regime and the distribution of biota is critical for managing flows in regulated rivers. In northern Victoria, Australia, efforts are presently underway to restore a natural, intermittent flow regime to several streams which, for over 100 years, have received perennial diversions as part of a stock, irrigation and domestic water supply.2. Bayesian, model‐averaged, binomial regression was used to predict probabilities of occurrence for 13 fish species, including five non‐native species, based on hydrologic variables characterising both the current and modelled future flow regimes at 10 sites representing a range of hydrologic regimes (categorised here as heavily regulated, moderately regulated and unregulated).3. Regression models accurately predicted present probabilities of occurrence for most species across all sites. The models predicted a reduced likelihood of large, native, flow‐dependent species occurring at regulated sites following flow restoration. Predictions regarding the future distribution of widespread species including two small‐bodied native and four exotic species were less certain as current distributions of these widespread species were unrelated to hydrologic variables we examined and thus unlikely to be significantly affected by flow restoration. The distributions of two small native species currently restricted to unregulated sites are predicted to increase throughout the system.4. This study illustrates the effects of artificially induced perennial flow on lowland fish distributions. Furthermore, the combination of pre‐restoration data together with predictive modelling provides valuable insights into the likely outcomes of flow regime shifts.5. This study clearly demonstrates the value of combining empirical research and modelling in guiding environmental flow and ecosystem restoration decisions. Knowledge from the study is now helping guide management decisions and the development of mitigation strategies to protect highly valued species in the system from potential future threats.

Habitat representativeness score (HRS): a novel concept for objectively assessing the suitability of survey coverage for modelling the distribution of marine species

The occurrence of most species is linked to the distribution of specific combinations of environmental variables that define their occupied niche. As a result, the relationship between environmental variables and species occurrence can be used to model species distribution. However, when collecting data to construct such models, it is preferable to ensure that the survey coverage is representative of all available habitat combinations within the area as a whole to ensure that the model does not under- or over-estimate the actual species distribution. By using multi-variate statistical techniques, a habitat representativeness score (HRS) can be calculated to provide an objective assessment of whether a specific survey coverage will collect (or has collected) data that are representative of all available habitat variable combinations in an area. To demonstrate this approach, HRSs calculated using principal component analysis were used to assess the minimum number of evenly-spaced parallel north–south surveys required to adequately survey two study areas with differing levels of environmental heterogeneity for all available combinations of four habitat variables. For the more environmentally homogeneous study area, the HRS suggests that for this survey design a minimum of five evenly-spaced parallel transects, covering around 5% of the study area, would be required to obtain representative survey coverage for these four variables. However, for the more heterogeneous study area, at least eight evenly-spaced parallel transects, covering around 9% of the study area, would be required. Therefore, for a given survey design, more survey effort is required to obtain a representative survey coverage when the survey area is more variable. In both cases, conducting fewer surveys than these minimum values would produce an unrepresentative data set and this could potentially lead to the production of species distribution models that do not accurately reflect the true species distribution.