Native Vertebrates Research Articles

Reduced vertebrate diversity independent of spatial scale following feral swine invasions.

Biological invasions often have contrasting consequences with reports of invasions decreasing diversity at small scales and facilitating diversity at large scales. Thus, previous literature has concluded that invasions have a fundamental spatial scale‐dependent relationship with diversity. Whether the scale‐dependent effects apply to vertebrate invaders is questionable because studies consistently report that vertebrate invasions produce different outcomes than plant or invertebrate invasions. Namely, vertebrate invasions generally have a larger effect size on species richness and vertebrate invaders commonly cause extinction, whereas extinctions are rare following invertebrate or plant invasions. In an agroecosystem invaded by a non‐native ungulate (i.e., feral swine, Sus scrofa), we monitored species richness of native vertebrates in forest fragments ranging across four orders of magnitude in area. We tested three predictions of the scale‐dependence hypothesis: (a) Vertebrate species richness would positively increase with area, (b) the species richness y‐intercept would be lower when invaded, and (c) the rate of native species accumulation with area would be steeper when invaded. Indeed, native vertebrate richness increased with area and the species richness was 26% lower than should be expected when the invasive ungulate was present. However, there was no evidence that the relationship was scale dependent. Our data indicate the scale‐dependent effect of biological invasions may not apply to vertebrate invasions.

Vertebrate herbivory on shrub seedlings in California sage scrub: important but understudied interactions

Herbivory is poorly characterized in the endangered California sage scrub ecosystem, because previous studies were conducted only in winter and spring. To better understand vertebrate herbivore impacts, we first examined if and when vertebrate herbivores influence Artemisia californica seedling survivorship by examining differences in mortality between caged and uncaged seedlings. Then, we examined: (1) vertebrate herbivore preference of common sage scrub shrub species, and (2) which vertebrate species constitute important herbivores in the ecosystem. We found that mortality for uncaged A. californica seedlings was twice that of caged seedlings, and occurred in the summer and early fall, when previous studies in the system were not conducted. Short leaved shrubs, Artemisia californica and Eriogonum fasciculatum, were more susceptible to herbivory than broader leaved Salvia apiana and Eriodictyon trichocalyx. However, susceptibility likely depends on the herbivore assemblage, as the three main herbivore species [Sylvilagus audubonii (desert cottontail), Zonotrichia leucophrys (white-crowned sparrow; a bird, not a mammal), and Otospermophilus beecheyi (California gray squirrel)] all had different shrub preferences. Our results contrast with previous studies that suggests that native vertebrate herbivores facilitate shrub seedling survivorship by highlighting that late-season vertebrate herbivory may negatively affect shrub seedling survivorship. We demonstrate the complex but understudied role herbivores play in the sage scrub ecosystem, and highlight that further study of these key ecological interactions is warranted.

Globally important islands where eradicating invasive mammals will benefit highly threatened vertebrates.

Invasive alien species are a major threat to native insular species. Eradicating invasive mammals from islands is a feasible and proven approach to prevent biodiversity loss. We developed a conceptual framework to identify globally important islands for invasive mammal eradications to prevent imminent extinctions of highly threatened species using biogeographic and technical factors, plus a novel approach to consider socio-political feasibility. We applied this framework using a comprehensive dataset describing the distribution of 1,184 highly threatened native vertebrate species (i.e. those listed as Critically Endangered or Endangered on the IUCN Red List) and 184 non-native mammals on 1,279 islands worldwide. Based on extinction risk, irreplaceability, severity of impact from invasive species, and technical feasibility of eradication, we identified and ranked 292 of the most important islands where eradicating invasive mammals would benefit highly threatened vertebrates. When socio-political feasibility was considered, we identified 169 of these islands where eradication planning or operation could be initiated by 2020 or 2030 and would improve the survival prospects of 9.4% of the Earth’s most highly threatened terrestrial insular vertebrates (111 of 1,184 species). Of these, 107 islands were in 34 countries and territories and could have eradication projects initiated by 2020. Concentrating efforts to eradicate invasive mammals on these 107 islands would benefit 151 populations of 80 highly threatened vertebrates and make a major contribution towards achieving global conservation targets adopted by the world’s nations.

Changes in small native animal populations following control of European rabbits (Oryctolagus cuniculus) by warren ripping in the Australian arid zone

Context European rabbits have a great impact on native vegetation and small vertebrates in Australia. Rabbits consume vegetation and promote invasive plants and invasive predators, and compete directly and indirectly with native animals suppressing those populations. Aims We explored the changes in small native vertebrates and invertebrates following the removal of rabbits. Methods Warren ripping was undertaken on a property in south-western Queensland at four sites and the results of pitfall trapping were compared with four nearby paired control sites. Invertebrates and small mammals were counted in pitfall traps, and bird surveys were conducted in all treatment and control sites. Key results Following a rabbit-control program, we observed a four-fold increase in the number of dunnarts trapped in treatment plots, whereas no change was observed in control plots. The spring following the rabbit-control program also saw an increase in some lizards in treatment plots. Conclusions The presence of rabbits in arid-zone Australia can suppress native animal populations. Implications Many species of small native mammals and lizards rely on food sources that fluctuate greatly with environmental conditions. The presence of rabbits altering the landscape, supporting introduced predators, reducing vegetation and, therefore, insects, adds increased pressure for insectivorous species. Rabbit control through warren ripping in arid-zone Australia is an effective method to reduce rabbit numbers, and allowed for an increase in small vertebrates in treated areas.

Effectiveness of different herbivore exclusion strategies for restoration of an endangered rainforest community

Restoration practitioners commonly use plantings of young seedlings to restore endangered forest communities impacted by anthropogenic disturbance, such as weed invasion and deforestation. Forest recovery may be significantly hampered by browsing pressure from herbivores, and practitioners use a variety of plant guard techniques to reduce the negative impacts of browsing on plant establishment and facilitate ecosystem regeneration. However, there is limited knowledge of which herbivore exclusion methods are most effective in protecting growing seedlings from attack and whether such benefits vary amongst different resident plant species. We compared levels of herbivore damage for 54 native rainforest tree and shrub species amongst four guard treatments that are commonly deployed by restoration practitioners to protect revegetated seedlings from attack by non-native rusa deer (Cervus timorensis) and native vertebrate herbivores during their establishment: (1) small corrugated plastic guards; (2) tall wire guards that protect single seedlings from attack; (3) small fenced exclusion plots that protect multiple revegetated seedlings as well as passively regenerating plants simultaneously; (4) unguarded plants. We also evaluated the effects of exclusion plots on the richness and composition of passively regenerating native vegetation in addition to the growth of actively revegetated seedlings through reduced herbivore activity. Herbivore activity was briefly surveyed using camera traps, and swamp wallabies (Wallabia bicolor) were found to be more active at the site than non-native rusa deer. All guard treatments significantly reduced browsing damage compared with unguarded plants, but corrugated plastic guards were less effective than wire guards and fenced exclusion plots. The fenced exclusion plots had the additional benefit of facilitating the passive regeneration of native plant species that may be cost prohibitive to regeneration otherwise. We also found that species varied in susceptibility to browsing, with eight species suffering high browse damage and five species low damage when unguarded. These findings highlight the potential for exclusion fences to provide more efficient and effective protection of browser preferred plants in the context of rainforest restoration.

Animal Visitation to Wild Pig ( Sus scrofa) Wallows and Implications for Disease Transmission.

Knowledge of animal visitation to locations where species aggregate is valuable for evaluating potential pathways of inter- and intraspecific transmission of infectious diseases. There is no research evaluating the potential of wallows created by invasive wild pigs ( Sus scrofa) as locations of transmission of infectious diseases. We monitored wild pig wallows by using trail cameras to determine the frequency with which wild pigs and native vertebrate species visited wallows and to characterize these interactions for their potential for disease transmission. We placed cameras from 20 June 2016 to 21 September 2016 at 16 individual wallows within 10 wallowing sites. Wild pigs of both sexes visited wallows frequently (115 total visits) for varying durations and exhibited wallowing and drinking behavior. We also observed 12 native mammalian and avian wildlife species using wallows at various frequencies (165 total visits). Of particular interest, nine of these species were observed drinking from wallows. Given the high frequency of wild pig visits to wallows and the drinking behavior they and native wildlife species exhibited, these locations might have an important role in transmission of diseases.

Invasive rat eradication strongly impacts plant recruitment on a tropical atoll.

Rat eradication has become a common conservation intervention in island ecosystems and its effectiveness in protecting native vertebrates is increasingly well documented. Yet, the impacts of rat eradication on plant communities remain poorly understood. Here we compare native and non-native tree and palm seedling abundance before and after eradication of invasive rats (Rattus rattus) from Palmyra Atoll, Line Islands, Central Pacific Ocean. Overall, seedling recruitment increased for five of the six native trees species examined. While pre-eradication monitoring found no seedlings of Pisonia grandis, a dominant tree species that is important throughout the Pacific region, post-eradication monitoring documented a notable recruitment event immediately following eradication, with up to 688 individual P. grandis seedlings per 100m2 recorded one month post-eradication. Two other locally rare native trees with no observed recruitment in pre-eradication surveys had recruitment post-rat eradication. However, we also found, by five years post-eradication, a 13-fold increase in recruitment of the naturalized and range-expanding coconut palm Cocos nucifera. Our results emphasize the strong effects that a rat eradication can have on tree recruitment with expected long-term effects on canopy composition. Rat eradication released non-native C. nucifera, likely with long-term implications for community composition, potentially necessitating future management interventions. Eradication, nevertheless, greatly benefitted recruitment of native tree species. If this pattern persists over time, we expect long-term benefits for flora and fauna dependent on these native species.

Reporting Australia’s forest biodiversity I: forest-dwelling and forest-dependent native species

ABSTRACTSpecies-level indicators based on the Montreal Process criteria and indicators framework are used to report Australia’s progress towards sustainable forest management, in national and international reporting of Australia’s forest biodiversity status and trends. This paper reviews the historical development of these indicators and related databases. A recent major development has been the establishment of a comprehensive suite of national inventory databases on Australia’s native forest-dwelling vertebrate fauna and vascular flora for reporting in the Australia’s State of the Forests Report series. Although these databases are incomplete, nearly 17 000 species records of vascular plants and over 2000 vertebrate species records have been assembled. Of the 2212 records of forest-dwelling vertebrate species, half (1101 species) are forest-dependent species that require a forest habitat for at least part of their lifecycle. Based on the frequency of habitat-use records, eucalypt open forest and eucalypt woodland forest are the most important habitat types for both forest-dwelling and forest-dependent vertebrate species. Monitoring of species varies nationally and across states and territories, with the most comprehensive approach undertaken in south-west Western Australia. Improved application of these databases to the reporting of species indicators will require improved collection of species records, inclusion of habitat data in records, and analysis of these records as time series with changing forest cover and condition. These databases also have application for informing forest-related indicators for the 2020 Aichi Biodiversity Targets of the Convention on Biological Diversity.

Thermal tolerance for two cohorts of a native and an invasive freshwater turtle species

The ability to tolerate environmental stress may determine invasion success of alien species. Comparative data on physiological thermal tolerance between native and invasive vertebrates are quite limited. Here, we assessed the difference in thermal tolerance between a native ( Mauremys reevesii ) and an invasive ( Trachemys scripta elegans ) freshwater turtle species. We incubated eggs of M. reevesii and T. scripta elegans from different cohorts at 29 °C, and measured the critical thermal minimum (CTMin) and maximum (CTMax) of hatchlings. Our results preliminarily showed that the hatchlings of T. scripta elegans had a greater high-temperature tolerance and wider tolerance range than the hatchlings of M. reevesii ; in the two-cohort system, individuals from the high-latitude cohort seemed to have greater low-temperature tolerance but similar high-temperature tolerance compared with those from the low-latitude cohort. Relatively greater thermal tolerance ability for T. scripta elegans might reflect its environmental adaptability to thermal stress.

Potential niche expansion of the American mink invading a remote island free of native-predatory mammals.

The success of an invasive species depends in part on its niche and the new niche opportunities that such species may find in the invaded habitat. Niche opportunities can be understood as the potential provided by a community to an invasive species to expand its niche by changes in habitat use, behavior, or diet, that favors population growth, reflected in the species occupying more habitat. This may occur under a favorable combination of access to resources that can be further favored by a lack of competitors and a release from natural enemies. The American mink (Neovison vison) is a crepuscular/nocturnal and semi-aquatic mustelid native to North America that generally concentrates activities at <100 m from the water. It has recently established an invasive population on Navarino Island in southern Chile. Here, the mink is now the top terrestrial predator free of predators or competitors. We hypothesized that this lack of potential predators and competitors, together with a more diurnal and terrestrial prey, have resulted in the mink expanding its spatial and temporal niche on Navarino Island as compared to that in its native habitats, expressed in occupancy of sites away from water and diurnal activity. We evaluated this by using 93 randomly-chosen camera-trap stations, occupancy models and mink daily activity patterns. Models showed a dynamic occupancy with the area occupied by mink being highest during summers and lowest in spring with seasonal changes in occupancy related to distance to water sources. Mink occupied and were active at sites up to 880 m from water sources during summers. Occupancy decreased at shorter distances from water during spring, but mink were still active at up to 300 m from water. Mink were active daylong during summers, and nocturnal and crepuscular during winter and spring. These results show that compared to the native and other invaded habitats, on Navarino Island mink use more terrestrial habitats and are more diurnal during summers, suggesting a niche expansion under new niche opportunities that may enhance the negative impacts of this predator on a myriad of small native vertebrates.

Contrasting ecological roles of non-native ungulates in a novel ecosystem.

Conservation has long focused on preserving or restoring pristine ecosystems. However, understanding and managing novel ecosystems has grown in importance as they outnumber pristine ecosystems worldwide. While non-native species may be neutral or detrimental in pristine ecosystems, it is possible that even notorious invaders could play beneficial or mixed roles in novel ecosystems. We examined the effects of two long-established non-native species—Philippine deer (Rusa marianna) and feral pigs (Sus scrofa)—in Guam, Micronesia, where native vertebrate frugivores are functionally absent leaving forests devoid of seed dispersers. We compared the roles of deer and pigs on seedling survival, seed dispersal and plant community structure in limestone karst forests. Deer, even at low abundances, had pronounced negative impacts on forest communities by decreasing seedling and vine abundance. By contrast, pigs showed no such relationship. Also, many viable seeds were found in pig scats, whereas few were found in deer scats, suggesting that pigs, but not deer, provide an ecosystem function—seed dispersal—that has been lost from Guam. Our study presents a discrepancy between the roles of two non-native species that are traditionally managed as a single entity, suggesting that ecological function, rather than identity as a non-native, may be more important to consider in managing novel systems.

Interactions between the invasive Burmese python, Python bivittatus Kuhl, and the local mosquito community in Florida, USA.

The Burmese python, Python bivittatus Kuhl, is a well-established invasive species in the greater Everglades ecosystem of southern Florida, USA. Most research on its ecological impacts focuses on its role as a predator and its trophic interactions with native vertebrate species, particularly mammals. Beyond predation, there is little known about the ecological interactions between P. bivittatus and native faunal communities. It is likely that established populations of P. bivittatus in southern Florida serve as hosts for native mosquito communities. To test this concept, we used mitochondrial cytochrome c oxidase subunit I DNA barcoding to determine the hosts of blood fed mosquitoes collected at a research facility in northern Florida where captive P. bivittatus and Argentine black and white tegu, Salvator merianae (Duméril and Bibron), are maintained in outdoor enclosures, accessible to local mosquitoes. We recovered python DNA from the blood meals of three species of Culex mosquitoes: Culex erraticus (Dyar and Knab), Culex quinquefasciatus Say, and Culex pilosus (Dyar and Knab). Culex erraticus conclusively (P = 0.001; Fisher’s Exact Test) took more blood meals from P. bivittatus than from any other available host. While the majority of mosquito blood meals in our sample were derived from P. bivittatus, only one was derived from S. merianae. These results demonstrate that local mosquitoes will feed on invasive P. bivittatus, a recently introduced host. If these interactions also occur in southern Florida, P. bivittatus may be involved in the transmission networks of mosquito-vectored pathogens. Our results also illustrate the potential of detecting the presence of P. bivittatus in the field through screening mosquito blood meals for their DNA.

Functional compensation by insular scavengers: the relative contributions of vertebrates and invertebrates vary among islands

When the extinction of some species results in loss of ecosystem functions, other species may be able to compensate for this loss. Functional compensation has recently been observed on islands where species are likely to become extinct; however, few studies have analysed functional compensation by scavengers in insular environments. Here, we investigated the ecosystem functions of vertebrate and invertebrate scavengers on Honshu, the main island of Japan, and offshore islands (four of the Oki Islands). The Oki Islands lack several native vertebrate scavengers (raccoon dogs, boars, martens, and foxes) that are abundant on Honshu. We experimentally placed mouse carcasses on the forest floors of Honshu (12 sites) and the Oki Islands (7 sites on Dōgo, 4 sites on Nishinoshima, 4 sites on Nakanoshima, and 3 sites on Chiburijima) in September–October 2014 and 2015. Nearly all of the mouse carcasses (95–100%) placed on the forest floor disappeared within 1 week. However, the relative importance of vertebrate and invertebrate scavengers varied among islands. Vertebrate and invertebrate scavengers contributed equally on Honshu (carcass removal by vertebrates, 47%), whereas vertebrate scavengers rarely contributed to carcass removal on three of the Oki Islands (carcass removal by vertebrates: 17% on Dōgo, 30% on Nishinoshima, and 5% on Nakanoshima). Consequently, invertebrate scavengers (Nicrophorus burying beetles) functionally compensated for the low species diversity of vertebrate scavengers on the three islands (carcass burial by Nicrophorus beetles, 65–95%). However, on the small island of Chiburijima, introduced raccoon dogs contributed to nearly all of the removals (93%), suggesting that introduced scavengers can compensate for the functional reduction. This functional compensation by scavengers may help stabilise the functions and/or services of scavengers in island environments.

ROADKILL IN THE BRAZILIAN CERRADO SAVANNA: COMPARING FIVE HIGHWAYS IN SOUTHWESTERN GOIÁS

This study described and analyzed the roadkill of native vertebrates in the southwest of the Brazilian State of Goias, evaluating the influence of the seasonal variation in climate and the influence of highway structure (e.g., two lane/one lane routes, road conditions). In this context, we collected samples each month over a one-year period on five of the region's highways, all of which originate in the town of Jatai, linking it to the neighboring towns of Acreuna, Apore, Itaja, Doverlândia and Portelândia. We recorded 1113 individuals (0.115 individuals/km/year), including nine amphibians, 55 reptiles, 223 birds,and 826 mammals. The two-lane highway had the highest species richness and abundance, and was significantly different from the other roads. We also found significant seasonal differences in overall abundance, and the species richness and abundance of the herpetofauna, with a greater number of collisions occurring during the rainy season. Over the long term, programs of environmental education - especially during the rainy season - may help to raise the awareness of drivers.

Disproportionately large ecological role of a recently mass-culled flying fox in native forests of an oceanic island

Human-wildlife conflicts pose a growing threat to many species worldwide and require increasingly innovative and multi-disciplinary resolutions. Because of their apparent simplicity and political appeal, lethal approaches like culling are often favoured, decisions to cull are typically poorly supported by scientific evidence and the limitations and drawbacks of culls minimised. As natural habitats decline and fruit crop production expands, fruit-eating bats in the Old World (family Pteropodidae) are increasingly in conflict with fruit farmers. This conflict is exemplified on Mauritius where the government has implemented two mass culls of a threatened flying fox (Pteropus niger) since 2015 in response to fruit-grower concerns. The culls and illegal hunting reduced the bat population by >50%. In this context, we sought to investigate the ecological role and service provided by the targeted flying fox through seed dissemination to gauge what may be lost as the species becomes rarer or extinct. We randomly sampled the woody native community in six of the best-preserved moist-to-wet native forests of Mauritius using 90 plots of 100m2 each and identified and measured the stem size of all woody plants ≥1cm in diameter. Species were classified by whether their fruits occur in the diet of the flying fox in an exclusive, confirmed or likely manner and we assumed that fruit consumption is equivalent to potential seed dissemination. The relative importance of these three categories to the total woody plant community was then quantified as the proportion of species richness, stem density and basal area (as a surrogate of biomass) that they represent. We also investigated whether the main traits of species (seed size, fruit size, and maximum stem diameter) vary among bat-dispersal categories and differ from those of species whose fruits are not currently known to be eaten by the flying fox. On average, although about a quarter of the native woody species (24.6%) have fruits confirmed as eaten and seeds dispersed by the flying fox, these species comprise about half (53.1%) of the stems sampled and the majority (63.1%) of the basal area of native woody plant in the island’s native forests. About half of that latter biomass figure comprises species for which the flying fox is the exclusive native vertebrate frugivore and seed disperser. Plants disseminated by the flying fox are typically large trees with large fruit and seeds. These trees are often key components of the canopy, therefore fulfilling structural engineer roles that provide resources and conditions for the survival of many forest species. The flying fox plays a disproportionally large ecological role in maintaining forest structure and biodiversity in the long-term. Consequently, lethal approaches to the conflict with fruit-farmers threaten not only an endangered species, but ecological processes central to the viability of native forests. Our findings highlight the importance of including the ecological costs of culling in decision-making processes intended to resolve human-wildlife conflicts.

Prey use by dingoes in a contested landscape: Ecosystem service provider or biodiversity threat?

In Australia, dingoes (Canis lupus dingo) have been implicated in the decline and extinction of a number of vertebrate species. The lowland Wet Tropics of Queensland, Australia is a biologically rich area with many species of rainforest‐restricted vertebrates that could be threatened by dingoes; however, the ecological impacts of dingoes in this region are poorly understood. We determined the potential threat posed by dingoes to native vertebrates in the lowland Wet Tropics using dingo scat/stomach content and stable isotope analyses of hair from dingoes and potential prey species. Common mammals dominated dingo diets. We found no evidence of predation on threatened taxa or rainforest specialists within our study areas. The most significant prey species were northern brown bandicoots (Isoodon macrourus), canefield rats (Rattus sordidus), and agile wallabies (Macropus agilis). All are common species associated with relatively open grass/woodland habitats. Stable isotope analysis suggested that prey species sourced their nutrients primarily from open habitats and that prey choice, as identified by scat/stomach analysis alone, was a poor indicator of primary foraging habitats. In general, we find that prey use by dingoes in the lowland Wet Tropics does not pose a major threat to native and/or threatened fauna, including rainforest specialists. In fact, our results suggest that dingo predation on “pest” species may represent an important ecological service that outweighs potential biodiversity threats. A more targeted approach to managing wild canids is needed if the ecosystem services they provide in these contested landscapes are to be maintained, while simultaneously avoiding negative conservation or economic impacts.

Feral cats threaten the outstanding endemic fauna of the New Caledonia biodiversity hotspot

Feral cats (Felis catus) are one of the most successful and harmful invasive predator species, leading to dramatic loss of biodiversity across the globe. Our study assessed feral cat predation in a major biodiversity hotspot: the New Caledonian archipelago. We focused on the consequences of this predation for the outstanding endemic fauna found throughout the rich range of New Caledonian natural habitats. We analyzed >5300 cat scats sampled from 14 selected sites representing the 4 main natural habitats, with 4 to 6 sampling sessions per year over >4years per habitat. Our study reveals previously unreported patterns of cat predation on both alien and endemic species. Throughout the archipelago, cats prey strongly upon squamates, flying foxes and petrels. Feral cat prey included at least 44 native vertebrate species, 20 of which are IUCN Red-listed threatened species. This study adds some 44.4% to the number of IUCN threatened species vulnerable to and preyed upon by feral cats on the world's islands. New Caledonia, while it represents only 0.12% of the total area of islands worldwide (Australia included), hosts 30.8% of IUCN threatened species known to be predated by feral cats. This study recommends prioritizing management and conservation strategies by focusing actions on maquis mosaic and humid forest habitats, where feral cats pose the greatest threat. To limit the impact of feral cats, we recommend conducting targeted management actions on sites key to threatened species conservation, and preventing arrival or promoting eradication on islets.

Native birds exploit leaf-mining moth larvae using a new North American host, non-native Lonicera maackii

ABSTRACTI document observations of birds feeding on the larvae of the leaf-mining moth Phyllonorycter emberizaepenella (Gracillariidae) in Michigan, USA. The larvae were feeding on Amur honeysuckle, Lonicera maackii (Caprifoliaceae), a non-native plant that has not been documented as a host for any species of Gracillariidae in North America, and which has few records of use by invertebrate herbivores anywhere in its range. Most bird observations were of chickadees (Paridae), which have been previously recorded feeding on leaf-mining insects. Observations also include three species of warblers (Parulidae) and one kinglet (Regulidae), which represent the first documentation of these families feeding on leaf-mining moth larvae. I describe this novel multitrophic interaction between a non-native plant, a native insect, and native vertebrate predators, and discuss the potential spread of the moth in North America, its use as a food source by birds, and the ecological implications.

Passive restoration following ungulate removal in a highly disturbed tropical wet forest devoid of native seed dispersers

AbstractOverabundant ungulate populations can alter forests. Concurrently, global declines of seed dispersers may threaten native forest structure and function. On an island largely devoid of native vertebrate seed dispersers, we monitored forest succession for 7 years following ungulate exclusion from a 5‐ha area and adjacent plots with ungulates still present. We observed succession from open scrub to forest and understory cover by non‐native plants declined. Two trees, native Hibiscus tiliaceus and non‐native Leucaena leucocephala, accounted for most forest regeneration, with the latter dominant. Neither species is dependent on animal dispersers nor was there strong evidence that plants dependent on dispersers migrated into the 5‐ha study area. Passive restoration following ungulate removal may facilitate restoration, but did not show promise for fully restoring native forest on Guam. Restoration of native forest plants in bird depopulated areas will likely require active outplanting of native seedlings, control of factors resulting in bird loss, and reintroduction of seed dispersers.

Marine dock pilings foster diverse, native cryptobenthic fish assemblages across bioregions

Anthropogenic habitats are increasingly prevalent in coastal marine environments. Previous research on sessile epifauna suggests that artificial habitats act as a refuge for nonindigenous species, which results in highly homogenous communities across locations. However, vertebrate assemblages that live in association with artificial habitats are poorly understood. Here, we quantify the biodiversity of small, cryptic (henceforth “cryptobenthic”) fishes from marine dock pilings across six locations over 35° of latitude from Maine to Panama. We also compare assemblages from dock pilings to natural habitats in the two southernmost locations (Panama and Belize). Our results suggest that the biodiversity patterns of cryptobenthic fishes from dock pilings follow a Latitudinal Diversity Gradient (LDG), with average local and regional diversity declining sharply with increasing latitude. Furthermore, a strong correlation between community composition and spatial distance suggests distinct regional assemblages of cryptobenthic fishes. Cryptobenthic fish assemblages from dock pilings in Belize and Panama were less diverse and had lower densities than nearby reef habitats. However, dock pilings harbored almost exclusively native species, including two species of conservation concern absent from nearby natural habitats. Our results suggest that, in contrast to sessile epifaunal assemblages on artificial substrates, artificial marine habitats can harbor diverse, regionally characteristic assemblages of vertebrates that follow macroecological patterns that are well documented for natural habitats. We therefore posit that, although dock pilings cannot function as a replacement for natural habitats, dock pilings may provide cost‐effective means to preserve native vertebrate biodiversity, and provide a habitat that can be relatively easily monitored to track the status and trends of fish biodiversity in highly urbanized coastal marine environments.