Flea (Siphonaptera) species richness in the Great Basin Desert and island biogeography theory

Numbers of flea (Siphonaptera) species (flea species richness) on individual mammals should be higher on large mammals, mammals with dense populations, and mammals with large geographic ranges, if mammals are islands for fleas. I tested the first two predictions with regressions of H. J. Egoscue's trapping data on flea species richness collected from individual mammals against mammal size and population density from the literature. Mammal size and population density did not correlate with flea species richness. Mammal geographic range did, in earlier studies. The intermediate‐sized (31 g), moderately dense (0.004 individuals/m²) Peromyscus truei (Shufeldt) had the highest richness with eight flea species on one individual. Overall, island biogeography theory does not describe the distribution of flea species on mammals in the Great Basin Desert, based on H. J. Egoscue's collections. Alternatively, epidemiological or metapopulation theories may explain flea species richness.     

Does the tropical agricultural matrix bear potential for primate conservation? A baseline study from Western Uganda

As for most large mammals, conservation research on primates usually focuses on protected areas, and yet not much is known about primate communities in land-use systems in the absence of hunting. Using line transects, we estimated population densities for four primate species in a mixed agroforest landscape up to a distance of 4000 m from a forest reserve, in a region where no primate hunting takes place. We then modelled encounter rates and cluster size in relation to landscape parameters by means of bivariate analysis and Generalised Linear Models (GLMs). Black-and-white colobus (Colobus guereza) were most common, with confidence intervals for density estimates of 31.1–62.8 individuals/km². Red-tailed monkeys (Cercopithecus ascanius) and blue monkeys (Cercopithecus mitis) occurred at 15.2–37.9 ind/km² and 13.9–36.7 ind/km² respectively, and chimpanzees (Pan troglodytes) at 1.0–2.8 ind/km². Chimpanzee nest numbers and distribution appeared to be significantly constrained by transect forest coverage, forest coverage within 500 m and distance from the main forest, whereas monkey sightings were generally less restricted by landscape variables. The considerable population density of monkeys suggests that, in the absence of hunting, mixed agroforest systems may play a relevant role in primate conservation and highlight that it is useful to consider primate ecology in land sharing approaches to conservation.     

Does availability of anthropogenic food enhance densities of omnivorous mammals? An example with coyotes in southern California

To evaluate whether the abundance of coyotes Canis latrans was influenced by the availability of anthropogenic foods in a humanized landscape, we compared three neighboring areas (hereafter referred to as NA, CA, and SA) under contrasting human pressures within the Santa Monica Mountains of California, USA. We quantified the use of anthropogenic foods by coyotes and assessed local densities within these three regions. Overall, 761 coyote feces were analyzed; identified food items were categorized into 11 food types (7 native and 4 anthropogenic). Though small mammals (lagomorphs and rodents) were the main prey of coyotes in all areas and seasons, log‐linear modeling of multiway contingency tables indicates that consumption of anthropogenic foods by coyotes varied significantly throughout study areas. Thus, in the most humanized area (CA; 24% of this region is residential habitat), anthropogenic foods (trash, livestock, domestic fruit) comprised seasonally between 14 and 25% of total items in coyote diets, whereas in the least humanized area (NA; 2% residential) anthropogenic foods only comprised seasonally between 0 and 3% of items. Coyote density, estimated by foot‐hold trapping surveys and by genotyping feces, was also highly variable between areas. The heavily human‐impacted CA area had the highest coyote density (2.4–3.0 ind. km^?2), whereas coyote density was significantly lower (0.3–0.4 ind. km^?2) in the least humanized area (NA). In the third region (SA; 10% residential), with an intermediate level of human pressure, both importance of anthropogenic foods in coyote diet (4–6%) and coyote density (1.6–2.0 ind. km^?2) were intermediate compared to the other regions. Our data suggest that subsidization by anthropogenic foods augments coyote densities and alters their diets in the Santa Monica Mountains, California. We include data from literature to show that anthropogenic foods are used by omnivorous mammals throughout the world. Surprisingly, however, the potential effects of allochthonous inputs on such species are not well‐understood. Thus, further research on this phenomenon in humanized landscapes is needed.     

Coastal forests of eastern Africa: status, endemism patterns and their potential causes

Eastern African coastal forests are located within the Swahili regional centre of endemism and Swahili-Maputaland regional transition zone in eastern Africa, between 1d? North and 25d? South, and 34—41d? East. Approximately 3167 km² coastal forest remains: 2 km² in Somalia, 660 km² in Kenya, 697 km² in Tanzania, 16 km² in Malawi, 3 km² in Zimbabwe and perhaps 1790 km² in Mozambique. Most forests are small (≤ 20 km²), and all but 19 are under 30 km² in area. Over 80% of coastal forest is located on government land, principally Forest Reserves; only 8.3 km² is found in National Parks (6.2 km² in Kenya (Arabuko-Sokoke), 2 km² in Tanzania (Mafia Island) and tiny patches in Zimbabwe). Coastal forests are an important and highly threatened centre of endemism for plants (c 550 endemic species), mammals (6 species), birds (9 species), reptiles (26 species), frogs (2 species), butterflies (79 species), snails (>86 species) and millipedes (>20 species). Endemic species are concentrated in the forests of the Tana River, between Malindi in Kenya to Tanga in northern Tanzania, and in southern Tanzania. Forests with highest numbers of endemics are: lower Tana River, Arabuko-Sokoke, Shimba Hills (Kenya); lowland East Usambara, Pugu Hills, Matumbi Hills, Rondo and Litipo and other plateaux near Lindi (Tanzania); the Tanzanian offshore island of Pemba; Bazaruto archipelago (Mozambique), and tiny forest remnants of southern Malawi, eastern Zimbabwe and Mozambique. Most coastal forest endemics have a narrow distributional range, often exhibiting single-site endemism or with scattered or disjunct distributional patterns. They are best interpreted as relicts and not the result of recent evolution. Relictualization probably started with the separation of the ancient Pan African rainforest into two parts during the Miocene. The coastal forests are interpreted as a ‘vanishing refuge’ with the endemic species gradually becoming more and more relict (and presumably extinct) due historically to climatic desiccation and more recently to human destruction.     

珠江口附近海区甲壳类动物的区系特征及其分布状况

根据2006年8月（夏季）、2006年10月（秋季）、2006年12月（冬季）和2007年4月（春季）珠江口附近海区的底拖网调查资料,分析了该海域甲壳类动物的区系特征和分布状况.结果表明：本次调查共采获甲壳类动物54种,分隶于2目17科25属,其中,虾类22种、蟹类22种、虾蛄类10种;该海域甲壳类动物多数为热带 亚热带的暖水性种类,少数为广温性种类,未出现暖温性和冷温性种类;广盐性的种类最多,其次为高盐性种类,低盐性种类最少;大多数种类属于印度洋 西太平洋区系;调查海域的甲壳类动物种类与东海、菲律宾海、印度尼西亚海、日本海关系较密切,与黄海、渤海、朝鲜海关系较疏远.调查海域甲壳类动物的优势种为周氏新对虾、口虾蛄、武士蟳、红星梭子蟹、猛虾蛄、锈斑蟳、日本蟳、长叉口虾蛄、中华管鞭虾、三疣梭子蟹和逍遥馒头蟹.出现的种类数以秋季最多（33种）,春季最少（26种）.甲壳类资源密度在水深0～40 m水域较高,在水深10～20 m最密集.调查海域甲壳类动物的平均资源密度为99.60 kg·km^-2,以夏季最高（198.93 kg·km^-2）、春季最低（42.35 kg·km^-2）;组成甲壳类动物的3个类群中,蟹类的资源密度最高（41.81 kg·km^-2）,其次是虾类（38.91 kg·km^-2）,虾蛄类最低（18.88 kg·km^-2）;各类群资源密度存在明显的季节变化,虾类在夏季最高（120.32 kg·km^-2）、春季最低（0.67 kg·km^-2）,蟹类和虾蛄类则均在冬季最高（62.01和29.49 kg·km^-2）、秋季最低（24.64和6.30 kg·km^-2）.     

Habitat use,abundance, and persistence of Neotropical migrant birds in a habitat matrix in northeast Belize

ABSTRACT To ensure adequate protection of nonbreeding habitats used by Neotropical migratory landbirds, we must first address questions about habitat use and quality. On the Yucatan peninsula, migrants use many habitats, several of which remain unstudied, and methodological differences preclude interhabitat comparisons based on studies to date. We used distance sampling along line transects in six habitats in northeast Belize to examine use of previously unstudied habitats (e.g., salt marsh) by Neotropical migrants and to permit comparison across habitats. We calculated unadjusted and adjusted (for detectability) density estimates for individual migrant species and for all species combined to generate hypotheses about habitat quality based on the assumption that density and quality are positively correlated. Adjusted density estimates for all migrants were highest in black mangrove habitat (1799 ± 110 ind/km²), intermediate in three forest types and milpa (range 598–802 ind/km²), and lowest in salt marsh (207 ± 32.3 ind/km²). By combining density estimates with habitat availability in our study region, we estimated that evergreen forest and black mangrove supported 70% and 9% of the region's migrant population, respectively. At the species level, five of the 10 most common species had habitat preferences (>50% detections in one habitat). Given the diversity of habitat preferences among species and apparent seasonal movements, our results indicate that Neotropical migrants in northeast Belize are dependent on a matrix of interconnected habitats.     

Influence of ethanol and ethylene on the seed germination of three nymphaeid water plants

1. We offered Scenedesmus obliquus in five densities, from 0.5 to 8 ± 10⁶ cells ml^?1, to the rotifer Anuraeopsis fissa. Growth rates (r) during the exponential phase (first 7 days) were significantly and positively related to food density. The r values (mean ± SD) varied between 0.454 ± 0.067 and 0,856 ± 0.090, from the lowest to the highest food concentration, respectively. Population growth went through a phase of exponential increase which lasted from 7 to 10 days before a plateau and, in some cases, a decrease occurred. 2. There was a linear relation between food density and rotifer plateau density. At the highest food density, a peak abundance (mean ± SD) of 2312 ± 226 individuals ml^?1 was reached, while at the lowest food density there was no identifiable single peak but a plateau, at a density of 361 ± 62 ind. ml^?1. 3. The egg ratio decreased with increasing population density. The ratio of loose eggs to eggs attached to females indicated that more eggs became detached at higher food densities. 4. As in many other rotifer species studied so far, population density of A. fissa was less stable at higher algal food concentrations. Numerically, A. fissa could be grown at twice the density achieved in Brachionus.     

Population dynamics and social organization of sambar (Rusa unicolor unicolor) in Horton Plains National Park,Sri Lanka

We estimated the population density and investigated the social organization of sambar (Rusa unicolor unicolor) in Horton Plains National Park (HPNP), Sri Lanka. Distance sampling was conducted along six strip transects every month for a period over 3 years (2018–2020) to estimate the density of the sambar population in grasslands of HPNP (9.4 km²), while the antler stage of males and the behavior of individuals were recorded to describe the population's reproductive stage and hence the social organization. Population density estimates showed relative stability over the 3 years and varied over the seasons but with consistent peaks from year to year with the highest population densities recorded in November–December (212.93 ± 25.38 animals/km² in 2018, 187.91 ± 28.51 in 2019, and 179.76 ± 31.85 in 2020). The highest percentage of males in hard antlers was observed from November through January, while the percentage of antlers cast sambar peaked from March to April each year. Hinds were observed with newborn calves throughout the year, but the highest number of newborn calves were recorded from July to August each year, while the number of calves counted each year varied from 210 to 267 individuals. The mean group size was variable throughout each year with the largest groups recorded from September to December (up to 52), the period accompanied by the most observations of mating and sparring behavior. Although on a tropical island, HPNP is situated on a rolling plateau landscape in the highlands, where sambar showed a degree of reproductive seasonality somewhat similar to temperate cervid species.     

Status and structure of the griffon vulture (Gyps fulvus) population in Crete

Griffon vulture (Gyps fulvus) population surveys were conducted during 1996–2002 in the island of Crete (Greece) to document population status and structure. Fieldwork was carried out during the breeding period when birds could be monitored in their colonies. Total population size was estimated at 379 individuals (range = 341–417) with adult birds comprising 63%. The breeding population was estimated at 141 pairs, which were distributed on an average in 23 colonies per year (range = 16–30) while the mean number of breeding pairs that laid eggs was 98 (range= 64–126). Crete thus supports the largest insular population of the species in the world and hosts 70–80% of the breeding population of the species in Greece. Population density was estimated at 6.9 individuals/100 km², 2.6 breeding pairs/100 km² and 1.8 nesting pairs/100 km². The average home range of an occupied colony (i.e., breeding group) was estimated at ca. 204 km² producing a theoretical foraging range of 8 km radius around the breeding cliff. No trends in the total number of individuals and breeding pairs appeared to exist, although significant differences in population size of individual colonies occurred between the years. The majority of the population was concentrated in small-sized colonies, which showed a low occupancy rate. The number of abandoned sites and the colonization of new ones could represent a shift of breeding pairs to alternative colonies provoked by local food abundance and conspesific attraction.     

Demography and population growth of Asplanchna girodi (Rotifera) as a function of prey (Anuraeopsis fissa) density

Laboratory studies on population growth and life table demography of Asplanchna girodi were conducted at 25±1 °c using Anuraeopsis fissa as prey at four (250, 500, 1000 and 2000 ind ml^–1) densities. A prey density of 100 ind ml^–1 per predator per day did not support A. girodi, while at the highest prey concentration, A. girodi reached a peak of 115±7 ind ml^–1. The age distribution of A. girodi indicated that non-adults constituted about 2/3rd of the population at all prey concentrations. A decrease in prey availability resulted in increased mortality of non-adults. At the highest prey density, the rate of population increase (r) was 1.51 d^–1. The significance of estimating mortality in population growth studies is discussed.Life table demography of A. girodi was also studied using the same prey at the same concentrations. None of the survivorship parameters (e.g. mean lifespan and mean survivorship) showed a significant relation to prey density. Net reproductive rate and generation time (but not rate of population increase) were affected by prey abundance.     

Estimation of roe deerCapreolus capreolus and mouflonOvis aries densities, abundance and habitat use in a mountainous Mediterranean area

The abundance, density, and habitat use of roe deerCapreolus capreolus (Linnaeus, 1758) and mouflonOvis aries Linnaeus, 1758 were studied in a confined Mediterranean area in Greece with a dung survey based on the faecal accumulation rate (FAR) technique. Estimated density was modelled with generalized additive models using altitude, habitat type, and slope as potential covariates. Model selection among the set of candidate models was conducted based on their generalized cross-validation score. Roe deer had an estimated mean density of 13.9 ind./km² and the best model included slope and habitat type as covariates. The mean density of mouflon in the study area was 22.1 ind./km² and the best model used altitude and habitat type as covariates. For both species, the highest densities were encountered in abandoned cultivations and glades, followed by conifer forests, while the lowest densities were observed in maquis. However, use of open habitats by mouflon was much greater than it was for roe deer. The strong preference of mouflon (a grazer species) for open habitats that were abundant with grasses probably reflected food availability and contrasted with the more diverse habitat use by roe deer (a selective browser).     

Competitive advantage of the invasive copepod Oithona davisae over the indigenous copepod Oithona nana in the Marmara Sea and Golden Horn Estuary

Around 2010, the alien copepod Oithona davisae was introduced to the Marmara Sea and Golden Horn Estuary to live alongside the native species, Oithona nana. By October 2015, the population number, including nauplii, of the introduced species (213,600 ind m^?3) was higher than that of the native species (54,900 ind m^?3) and close to that of O. davisae in Sevastopol Bay of the Black Sea (342,000 ind m^?3) where it appeared 14 years ago. A high percentage of O. davisae females with ovisacs (up to 30% of total female number) carrying up to 15.1 ± 2.1 eggs in the sac and the predominance of nauplii in the population (up to 95% of the total population number) indicate that this alien copepod has become a permanent component of the Marmara Sea and Golden Horn Estuary ecosystem. Our experiments showed that in comparison with widely euryhaline O. davisae, O. nana is a stenohaline species. It has a salinity tolerance in the range of 13–27 psu and, in spite of having a larger body, a lower body density (1.037 ± 0.007 g cm^?3) and sinking speed. Carbon-specific respiration rates of both species were close (0.32–0.38 μL O₂ μgC^?1 day^?1) and similar to that of O. davisae from the Black Sea during this period but the frequency and speed of routine jumps, and the maximum escape reaction speed (up to 23.3 ± 1.7 cm s^?1) in O. davisae from the Marmara Sea were significantly higher. This indicates the higher adaptive potential of O. davisae in this situation compared to that of O. nana.     

Population Survey and Demographic Features of a Coastal Island Population of <Emphasis Type="Italic">Alouatta clamitans</Emphasis> in Atlantic Forest,Southeastern Brazil

Brown howlers (Alouatta clamitans) are endemic to the Atlantic Forest. Because only 7.5% of this fragmented forest remains in Brazil, there is an urgent need for studies of its ecology. Understanding island populations, still poorly researched in the relatively well-studied Alouatta, can provide important information for understanding habitat fragmentation and conservation. We studied brown howlers on the northern portion of the coastal and protected island, Ilha do Cardoso State Park. We used distance sampling methods on 5 transects to estimate population density of the howlers. Estimated howler density on the island is 10.6 individuals/km², with a total of 36 (21–62) individuals in a 3.4 km² area. The density is low, but similar to that of other large and preserved areas. By triangulating on vocalization and following groups, we estimate that there are 10 groups with an average of 4.5 individuals per group. Groups comprise 42% adult females, 27% adult males, 20% juveniles, 7% infants, and the remaining 4% subadult males. Howlers apparently use all appropriate habitats, including Atlantic Forest of plains and slopes. We believe that the howler population is maintaining a typical replacement on the island, with low birth rates and high survival rates, but long-term studies are required to test this. Small group size and associated social structure may be due to the particular environmental conditions on Ilha do Cardoso State Park.     

Ecology of a community of mammals in a seasonailly dry forest in Roraima, Brazilian Amazon

A community of middle-sized and larger mammals was studied in a seasonally dry forest in the far north of the Brazilian Amazon. Diurnal and nocturnal surveys were carried out through the linetransect method, in 5 different forest types along a 10-km transect. Data were collected an density, biomass, and use of the forest types, and forest strata by the mammals. The terrestrial community of mammals was more abundant than the arboreal one, with ungulates contributing to the bulk of the biomass, as a result of Maracá being highly seasonal Overall densities were lower than in other sites in the neotropics, varying from 90.2 ind/km² in mixed forest, to 159.9 ind/km² in Terra Firme forest, whereas biomass, due to the contribution of large mammals, was much higher (2613.2 kg/km² in mixed forest, and 4351.6 kg/km² in Terra Firme forest). This study confirms that the animals surviving in larger numbers in these highly seasonal forests, where food productivity may be very low during the dry season, are those that have larger home ranges and travel longer distances in search of food.     

A refined model of body mass and population density in flightless birds reconciles extreme bimodal population estimates for extinct moa

Flightless birds were once the largest and heaviest terrestrial fauna on many archipelagos around the world. Robust approaches for estimating their population parameters are essential for understanding prehistoric insular ecosystems and extinction processes. Body mass and population density are negatively related for extant flightless bird species, providing a method for quantifying densities and population sizes of extinct flightless species. Here we assemble an updated global data set of body mass and population densities for extant flightless birds and estimate the relationship between these variables. We use generalised least squares models that account for phylogenetic relatedness and incorporate the effects of limiting factors (e.g. habitat suitability) on population density. We demonstrate the applicability of this allometric relationship to extinct species by estimating densities for each of the nine species of moa (Dinornithiformes) and generating a combined spatially explicit map of total moa density across New Zealand. To compare our density estimates with those previously published, we summed individual species' abundances to generate a mean national density of 2.02–9.66 birds km⁻² for low- and high-density scenarios, respectively. Our results reconcile the extreme bimodality of previous estimates (< 2 birds km⁻² and > 10 birds km⁻²) and are comparable to contemporary densities of large herbivorous wild mammals introduced into New Zealand about 150 yr ago. The revised moa density has little effect on the harvest rates required to bring about extinction within 150–200 yr, indicating that rapid extinction was an inevitable response to human hunting, irrespective of the initial population of moa.     

Density Estimation of the Endangered Udzungwa Red Colobus (Procolobus gordonorum) and Other Arboreal Primates in the Udzungwa Mountains Using Systematic Distance Sampling

Estimates of population density and abundance are essential for the assessment of nonhuman primate conservation status, especially in view of increasing threats. We undertook the most extensive systematic primate survey yet of the Udzungwa Mountains of Tanzania, an outstanding region for primate endemism and conservation in Africa. We used distance sampling to survey three arboreal monkey species, including the endangered and endemic Udzungwa red colobus (Procolobus gordonorum). Overall, we encountered 306 primate clusters over 287 km walked along 162 line transects. We found the lowest cluster densities for both red colobus and Angolan colobus (Colobus angolensis; 0.8 clusters/km²) in the least protected forest (Uzungwa Scarp Forest Reserve, US), while we found the highest densities (3.2 and 2.6 clusters/km² for red colobus; 3.2 and 2.7 clusters/km²for Angolan colobus) in two large and protected forests in the national park. Unexpectedly, Magombera, a small forest surrounded by plantations, had the highest densities of red colobus (5.0 clusters/km²), most likely a saturation effect due to the rapid shrinking of the forest. In contrast, Sykes’ monkey (Cercopithecus mitis monoides/moloneyi) had more similar densities across forests (3.1–6.6 clusters/km²), including US, suggesting greater resilience to disturbance in this species. For the endemic red colobus monkey, we estimated an abundance of 45–50,000 individuals across all forests, representing ca. 80% of the global population. Though this is a relatively high abundance, the increasing threats in some of the Udzungwa forests are of continued concern for the long-term survival of red colobus and other primates in the area.     

The effect of experimental removal of red foxesVulpes vulpes on spring density of brown haresLepus europaeus in western Poland

Red foxesVulpes vulpes (Linnaeus, 1758) were experimentally removed in two nearby areas located in western Poland to verify the hypothesis about the limiting impact of their predation on the low-density population of brown haresLepus europaeus (Pallas, 1778) (4.4-10.6 ind./km² in late autumn). In 1996/1997–2001/2002 foxes were culled (mainly in autumn and winter) in the reduction area (32 km²), whereas in the control area (34 km²) intensive culling was carried out only in 2000/2001–2001/2002. Indices of fox and hare spring densities were estimated using spotlight counts, as mean numbers of individuals observed per 10 km of the counting route. Annual changes in the fox density indices were negatively correlated with the bag of foxes, and annual changes in the hare density indices were negatively related to the annual changes in fox density indices. The fox density indices were significantly lower in the reduction area than in the control one only in 2000–2001 (2.8 times, on average), and in the same years, the hare population responded with higher density (1.7 times, on average). The hare responses took place without time delay, which suggests that the changes in fox abundance affected the situation of hares primarily in the autumn-winter season.     

The status of foxes Vulpes vulpes on the Isle of Man in 1999

1. Foxes Vulpes vulpes probably did not occur naturally on the Isle of Man, but were present in small numbers in the mid 19th century. They were introduced again in the 1980s, and in 1990 the population was estimated at 120–300 individuals (20–50 per 100 km²) on the basis of field signs. We used a nocturnal spotlight transect survey technique to assess the status of foxes on the Isle of Man in September 1999. This method had previously been used effectively to estimate fox densities in populations as sparse as 16 per 100 km². We surveyed a total of 852 km over a period of eight consecutive nights, during weather conditions which allowed excellent visibility. No foxes were seen. 2. By comparison with equivalent survey efforts in reference areas of mainland Britain, we conclude that post‐breeding fox density on the Isle of Man was certainly below 2.5 per 100 km², implying a maximum of 15 foxes on the entire island. We estimate a probability of only 15–25% that a fox population of 1 per 100 km² was present but not detected; this would be equivalent to only five or six individuals on the whole island. Foxes may even be entirely absent, although unsubstantiated sightings continue to be reported. 3. This finding is significant in understanding the ecology of the Isle of Man, and in planning the conservation of a number of ground‐nesting bird species there, as well as for farming interests, and for contingency planning against an accidental introduction of rabies.     

Distribution and abundance of large herbivores in a northern Australian tropical savanna: A multi‐scale approach

Australian mammals have exhibited exceptionally high rates of decline since European settlement 230 years ago with much focus on small mammals in northern tropical savannas. In these systems, little scientific attention has been given to the suite of grazing macropods, family Macropodidae, (common wallaroo (Osphranter robustus), antilopine wallaroo (O. antilopinus) and agile wallaby (Notamacropus agilis)). These species may be impacted by feral herbivores and contemporary fire regimes, two threats linked to small mammal declines. A multi‐scale approach using aerial surveys, road surveys and camera trapping was utilised to determine the effects of feral cattle and fire on the distribution and abundance of large macropods in the North Kimberley bioregion. Feral cattle density and biomass exceeded that of macropods regardless of survey technique. Density estimates for cattle were up to 125 times higher (0.3–10.0 km^?2) than estimates for macropods (0.08–0.49 km^?2). Cattle biomass, based on the aerial survey estimates (corrected for perception bias), were 15 and 95 times higher than macropods for infertile (279 vs. 19 kg km^?2) and fertile savannas (518 vs. 5 kg km^?2), respectively. Proximity to the nearest pastoral station was a significant predictor of the aerial sightings of feral cattle (P ≤ 0.05). Abundance and foraging activity of cattle were positively associated (P ≤ 0.05) with recently burnt areas. In contrast, camera trapping showed agile wallaby and wallaroo occurrence and foraging were associated with longer unburnt areas (P ≤ 0.05). Agile wallaby and wallaroo were negatively associated with cattle (P ≤ 0.05) and showed substantial diurnal and seasonal separation consistent with an antagonistic interspecific interaction. Results also suggest that the agile wallaby is the primary prey of the dingo, not wallaroo. Collectively, this study suggests that recent landscape changes such as altered fire regimes and introduced herbivores have negatively impacted large grazing macropod species.     

Introduced species as moving targets: changes in body sizes of introduced lizards following experimental introductions and historical invasions

Introduced species usually fail to establish, but when they succeed, may undergo character release and rapid evolutionary divergence in novel environments. We collected brown anoles (Anolis sagrei: Lacertilia: Iguanidae) from a single Florida population and released them onto two ecologically different dredge-spoil islands in central Florida (forested and non-forested) and measured differences in population growth, individual growth, body size, and condition over four years. The population on the non-forested island expanded twice as fast as the forested island population and reached a density of ca. 12,000 lizards ha^–1 and a biomass of ca. 43.3 kg ha^–1, among the largest values recorded for non-aggregated terrestrial vertebrates. First-year progeny grew larger than their surviving parents on both islands, indicating character release occurred in early stages of both invasions. However, in subsequent years, lizards became larger on the forested island, but smaller on the non-forested island. Body condition declined over time on both islands, but the effect was most dramatic on the non-forested island. Lizards on the forested island had the lowest survival rates and highest tail autotomy frequencies. These results were attributed to differences in abiotic and biotic conditions on the two islands. Brown anoles are generally larger on islands where they have been introduced than on their native Caribbean islands, and are much larger on mainlands than on islands, indicating character release occurred at larger geographic scales as well. Habitat influences the morphology of introduced species possessing the ability to rapidly adapt to local conditions, presenting invasive species managers with moving targets.