The significance of spatial and temporal patterns of algal mat deposition in structuring salt marsh vegetation

Question: Are there hot spots of algal mat deposition in space and time at the marsh scale and, if so, how does this affect the coexistence of a dominant (Spartina anglica) and gap dependent (Salicornia europaea) species? Location: The Rattekaai salt marsh in the Scheldt estuary in the southwestern Netherlands (NW Europe). Methods: Mat cover and the abundance of the gap dependent species Salicornia europaea were monitored at the scale of a marsh. The effects of mat cover on the vegetation structure were studied by applying three mat removal treatments over three growing seasons. Results: The low marsh border was found to be a hot spot of algal mat deposition during the growing season, which had a correlated spatial pattern between two successive years at a 20 m X 20 m scale. The combination of duration, timing and repetition of mat cover determined growth inhibition of the competitive dominant Spartina anglica, and thereby the abundance of subordinates such as Salicornia europaea. Mat cover reduced the storage of carbon reserves in Spartina and our results imply that repetition of non‐lethal mat cover can lead to ‘gap creation’. Gaps gave only temporary habitat to less dominant species since Spartina quickly re‐invaded them. The gap dependent annual Salicornia was most abundant at intermediate levels of disturbance measured as a function of both space and time. Conclusions In addition to disturbance level, the spatial and temporal distribution of disturbance are important in creating and maintaining habitat for gap dependent species. Relatively small disturbances will have a large effect on diversity if the spatial and temporal distribution of the disturbances leads to ‘disturbance hot spots’.     

Habitat preferences and habitat restoration options for small‐bodied and juvenile fish species in the northern Murray–Darling Basin

Degradation of instream habitats in the northern Murray–Darling Basin has occurred through numerous stressors, including siltation, clearing of bankside vegetation, intrusion of livestock and impacts of pest species. A better understanding of habitat preferences of native fish species could help guide future instream habitat restoration actions. The habitat choices of seven native fish species, juvenile Murray Cod (Maccullochella peelii), juvenile Golden Perch (Macquaria ambigua ambigua), juvenile Silver Perch (Bidyanus bidyanus), adult Murray–Darling Rainbowfish (Melanotaenia fluviatilis), adult Olive Perchlet (Ambassis agassizii), adult Un‐specked Hardyhead (Craterocephalus stercusmuscarum fulvus) and adult carp gudgeons (Hypseleotris spp.) were tested in preference troughs to help inform potential habitat restoration actions in the Condamine catchment. Each species was given a choice between pair combinations of open sandy habitat, submerged macrophytes, emergent plants and rocky rubble. Habitat preferences varied between species. Murray Cod, Golden Perch, carp gudgeons and Olive Perchlets preferred structure over open sandy habitat, whilst juvenile Silver Perch, Un‐specked Hardyhead and Murray–Darling Rainbowfish did not avoid open sandy habitats. Juvenile Murray Cod preferred rocky rubble habitat over all other habitat choices. Use of complex rock piles to provide nursery habitat for Murray Cod populations is a potential restoration option. Introduction of rock could also benefit Golden Perch and carp gudgeons. Use of emergent plants, submerged macrophytes and rocky rubble for habitat restoration all appear to have merit for one or more species of small‐bodied fishes or juvenile stages of larger sized fishes. Rocky rubble or floating attached macrophytes could be viable restoration options in areas too turbid to establish submerged macrophytes. These habitat interventions would complement existing actions such as re‐snagging and provision of fish passage to assist with sustainable management of native fish populations.     

Colonization of Sphagnum on land uplift islands in the Baltic Sea: time, area, distance and life history

Aim To test whether species richness of Sphagnum mosses on islands in a land uplift archipelago is related to island age, area or connectivity, and whether the frequency of different species can be predicted by their life history and autecology. Location The northern Stockholm archipelago in the Baltic Sea, east‐central Sweden, with a current land uplift rate of 4.4 mm year^?1. Methods We sampled 17 islands differing in area (0.55–55 ha), height (3.6–18 m, representing c. 800–4000 years of age) and distance from mainland (1.6–41 km). For each Sphagnum patch we measured area, height above sea level, horizontal distance from the shore and shading from vascular plants. Factors affecting island species richness, species frequency and habitats on the islands were tested by stepwise regressions. Species frequency was tested on nine life history and autecological variables, including estimated abundance and spore output on the mainland, habitat preference and distribution. Results We recorded 500 patches of 19 Sphagnum species, distributed in 83 rock pools on 14 islands. Island species richness correlated positively with island area and with degree of shelter by surrounding islands, while distance from the mainland, connectivity, height or age did not add to the model. Species frequency (number of colonized islands and rock pools) was mainly predicted by spore output on the mainland and by habitat preference (swamp forest species were more frequent than others), while spore size, for example, did not add to the model. Species differed in mean height above and horizontal distance from the shore, area of occupied rock pools and in the degree of shading of patches. The mean horizontal distance from the shore and the area of occupied rock pools correlated positively with the normal growth position above the water table among species. Spore capsules were found in only 2% of patches, mostly in the bisexual Sphagnum fimbriatum. Main conclusions The presence of Sphagnum in the Stockholm archipelago seems to be governed by regional spore production and habitat demands. Sphagnum does not appear to be dispersal limited at distances up to 40 km and time spans of centuries. Species with a high regional spore output have had a higher colonization rate, which, together with the rarity of spore capsules on the islands, indicate the mainland as a source for colonization rather than dispersal among islands. Swamp forest species seem more tolerant to the island conditions (summer droughts and some salt spray) than open mire species. The different distances from the sea occupied by the species indicate a slow, continuous succession and species replacement towards the island interior as islands are being uplifted and thus expand in area. This partly explains why larger islands harbour more species. Our results thus support some of the island biogeographical theories related to the species–area relationship.     

Fine‐scale habitat preferences and habitat partitioning by three mycophagous mammals in tropical wet sclerophyll forest,north‐eastern Australia

Abstract Fine‐scale habitat preferences of three co‐occurring mycophagous mammals were examined in a tropical wet sclerophyll forest community in north‐eastern Australia. Two of the three mammal species responded to fine‐scale variation in vegetation and landform around individual trap locations. At a broad scale, the northern bettong (Bettongia tropica), an endangered marsupial endemic to the Australian wet tropics region, showed a preference for ridges over mid‐slopes and gullies, irrespective of forest type. In contrast, the northern brown bandicoot (Isoodon macrourus), a widespread marsupial, displayed a preference for Eucalyptus woodland over adjacent Allocasuarina forest, irrespective of topographic category. The giant white‐tailed rat (Uromys caudimaculatus), a rodent endemic to the wet tropics, showed no particular preference for either forest type or topographic category. A multiple regression model of mammal capture success against three principal habitat gradients constructed from 21 habitat variables using principal component analysis indicated strong species‐specific preferences for fine‐scale vegetation assemblages. Bettongs preferred areas of Eucalyptus woodland with sparse ground cover, low densities of certain grass species, high density of tree stems and few pig diggings. Bandicoots, in contrast, favoured areas in both forest types with dense ground cover, fewer tree stems and greater numbers of pig diggings; that is, characteristics least favoured by bettongs. The striking differences in fine‐scale habitat preferences of these two mammals of similar body size and broad habitat requirements suggest a high degree of fine‐scale habitat partitioning. White‐tailed rats did not show preference for any of the habitat gradients examined.     

A Geographic Mosaic of Plant–Pollinator Interactions in the Eastern Caribbean Islands

The interplay between generalized and specialized plant–animal interactions is a core concept in understanding the evolution of mutualisms. Within the Eastern Caribbean, Heliconia bihai is a dominant forest species in the southern island of St. Vincent where H. caribaea is virtually absent. Heliconia caribaea is most common on the northern island of St. Kitts where H. bihai is restricted to the tops of the highest peaks. Both species are abundant on the central island of Dominica. We compared flowering patterns, nectar characteristics, and visitation frequency of hummingbirds in the two heliconias on the three islands to determine the extent of geographic variations in this plant–pollinator mutualism. The peak flowering season of the two heliconias was observed to be in April–May on all three islands with little within‐ and between‐island variations. Nectar production significantly varied between species and between islands. Visitation patterns by the principal hummingbird pollinators also varied between the islands: (1) on Dominica, only females of a single species of hummingbird pollinated the flowers of H. bihai (sexual specialization), whereas both sexes of the same hummingbird pollinated the flowers of H. caribaea (species specialization); (2) on St. Vincent, both sexes of the same hummingbird pollinated the flowers of H. bihai (species specialization); and (3) on St. Kitts, only females pollinated the flowers of H. bihai (sexual specialization), whereas several species of hummingbird visited the flowers of H. caribaea (species generalization). We propose that the Heliconia–hummingbird interactions in the Eastern Caribbean represent a geographically variable coevolutionary mosaic of plant–pollinator interactions.     

Species richness, environmental heterogeneity and area: a case study based on land snails in Skyros archipelago (Aegean Sea, Greece)

Aim To test the performance of the choros model in an archipelago using two measures of environmental heterogeneity. The choros model is a simple, easy‐to‐use mathematical relationship which approaches species richness as a combined function of area and environmental heterogeneity. Location The archipelago of Skyros in the central Aegean Sea (Greece). Methods We surveyed land snails on 12 islands of the archipelago. We informed the choros model with habitat data based on natural history information from the land snail species assemblage. We contrast this with habitat information taken from traditional vegetation classification to study the behaviour of choros with different measures of environmental heterogeneity. R² values and Akaike's information criterion (AIC) were used to compare the choros model and the Arrhenius species–area model. Path analysis was used to evaluate the variance in species richness explained by area and habitat diversity. Results Forty‐two land snail species were recorded, living in 33 different habitat types. The choros model with habitat types had more explanatory power than the classic species–area model and the choros model using vegetation types. This was true for all islands of the archipelago, as well as for the small islands alone. Combined effects of area and habitat diversity primarily explain species richness in the archipelago, but there is a decline when only small islands are considered. The effects of area are very low both for all the islands of the archipelago, and for the small islands alone. The variance explained by habitat diversity is low for the island group as a whole, but significantly increases for the small islands. Main conclusions The choros model is effective in describing species‐richness patterns of land snails in the Skyros Archipelago, incorporating ecologically relevant information on habitat occupancy and area. The choros model is more effective in explaining richness patterns on small islands. When using traditional vegetation types, the choros model performs worse than the classic species–area relationship, indicating that use of proxies for habitat diversity may be problematic. The slopes for choros and Arrhenius models both assert that, for land snails, the Skyros Archipelago is a portion of a larger biogeographical province. The choros model, informed by ecologically relevant habitat measures, in conjunction with path analysis points to the importance of habitat diversity in island species richness.     

Native and Introduced Ecosystem Engineers Produce Contrasting Effects on Estuarine Infaunal Communities

Cordgrasses in the genus Spartina are good examples of ecosystem engineers that modify habitat structure in estuaries throughout the world. In San Francisco Bay, California, USA, marshes containing native California cordgrass (Spartina foliosa) are being invaded by a hybrid (S. alterniflora × S. foliosa) formed after introduction of S. alterniflora. This study compared vegetation, sediment structure, and infaunal invertebrates in native and invaded marshes. We hypothesized that differences in the physical structure between S. foliosa and hybrid Spartina would be reflected in differences in density, biomass, diversity, and taxonomic composition of infauna. Hybrid Spartina modifies habitat structure more than S. foliosa by producing taller stems, and greater plant biomass both above- and belowground while occupying a much wider tidal range, thereby transforming open mudflats to a vegetated habitat. In general, S. foliosa areas contained significantly higher densities of benthic infauna than adjacent mudflats, while hybrid Spartina areas never contained greater infaunal densities than mudflats. This is because S. foliosa produces a moderate level of structure that can facilitate benthic invertebrates, whereas hybrid Spartina produces so much structure, particularly belowground, that it actually excludes invertebrates. Therefore, we suggest that these two closely related species both act as ecosystem engineers, but with opposing effects on invertebrate communities.     

Female tannin avoidance: a possible explanation for habitat and dietary segregation of giraffes (Giraffa camelopardalis peralta) in Niger

Niger is host to the last free‐roaming herd of G.c. peralta (Giraffa camelopardalis peralta). We examined the foraging preferences of these giraffe in their dry‐season habitats, with the goal of preserving the herd in the regions that they currently inhabit. The current dry‐season habitat comprises two distinct vegetation zones. In both of these zones the giraffe must exist alongside the people of this region. The giraffes exhibit a sexual segregation in their dry‐season habitat selection and forage choices. The females show a strong preference for the intermediate zone (IM) when lactating. The males and pregnant females show a preference for the Dallol Bosso (DB). Nursing cows exhibit an avoidance of tannins. Bulls and non‐nursing cows prefer high protein and high fat forage, while subadults show a strong preference for high protein and carbohydrate contents and moderate tannin levels. Combretum glutinosum is the preferred species for adults of both sexes in the IM. Males and females have strong preferences for both Acacia nilotica and Acacia seyal in the DB. Sub‐adults of both sexes strongly prefer Prosopis africana in the IM. Unlike females, males retain their preference for A. nilotica when in the IM.     

Enzyme production in the traps of aquatic <Emphasis Type="Italic">Utricularia</Emphasis> species

We studied the influence of habitat and increased mineral phosphorus and nitrogen loading on the extracellular activity of five selected hydrolases and pH in the trap fluid of the aquatic carnivorous plants, Utricularia vulgaris, U. australis, and U. foliosa (Lentibulariaceae). Enzyme activities in the trap fluid were determined using fluorometry. Phosphatase exhibited the highest activities in the traps of the European species as well as field-grown tropical U. foliosa. Trap enzyme production appeared to be uninfluenced by elevated dissolved mineral N or P concentrations both in the trap and ambient environment and thus, it seems to be constitutive. Enzyme activity in the trap fluid was determined by species and environmental conditions and varied significantly among sites within a single species. Trap fluid pH was between 4.2–5.1 in U. vulgaris and U. australis but between 5.7–7.3 in U. foliosa and seems to be regulated by the traps.     

Consistent performance of invasive plant species within and among islands of the Mediterranean basin

Since the success of an invasive species depends not only upon its intrinsic traits but also on particular characteristics of the recipient habitat, assessing the performance of an invader across habitats provides a more realistic analysis of risk. Such an analysis will not only provide insights into the traits related to invasiveness, but also the habitat characteristics that underpin vulnerability to invasion that, taken together, will facilitate the selection of management strategies to mitigate the invader’s effect. In the present study, we considered the Mediterranean basin islands as an excellent study region to test how the same invasive species perform in different habitats within a single island, and to scale up differences among islands with similar climate. We tested how the performance of three widespread plant invaders with clonal growth but contrasting life-history traits, a deciduous tree Ailanthus altissima, a succulent subshrub Carpobrotus spp., and an annual geophyte Oxalis pes-caprae, varied depending upon the species identity, habitat, and invaded island. The environmental parameters considered were habitat type, elevation, species diversity in the invaded plot, and several soil traits (% C, % N, C/N, pH, and relative humidity). The study documents that the performance of these three important and widespread plant invaders is dependent mainly on species identity, and less upon the invaded island’s general features. Likewise, differences in performance among habitats were only significant in the case of Ailanthus, whereas Carpobrotus and Oxalis appear to perform equally well in different environments. Ailanthus thus appears to have a broader spectrum of invasiveness, being able to invade a larger number of habitat types. On the contrary, Carpobrotus spp. have not yet invaded habitats different from those where the species have been originally introduced and where they are still commonly spread by humans. Oxalis distribution is mainly related to agricultural activities and disturbed sites, and the total area infested by this geophyte may be more reflection of the extent of suitable habitats than of invasiveness or ecological impact. Our results confirm the potential for these species to significantly alter the functioning of ecosystems in the Mediterranean islands and highlight the risk to other islands not yet invaded.     

Island biogeography of bats in Baja California, Mexico: patterns of bat species richness in a near-shore archipelago

Aim We studied the relationship between the size and isolation of islands and bat species richness in a near‐shore archipelago to determine whether communities of vagile mammals conform to predictions of island biogeography theory. We compared patterns of species richness in two subarchipelagos to determine whether area per se or differences in habitat diversity explain variations in bat species richness. Location Islands in the Gulf of California and adjacent coastal habitats on the Baja California peninsula in northwest Mexico. Methods Presence–absence surveys for bats were conducted on 32 islands in the Gulf of California using acoustic and mist‐net surveys. We sampled for bats in coastal habitats of four regions of the Baja peninsula to characterize the source pool of potential colonizing species. We fitted a semi‐log model of species richness and multiple linear regression and used Akaike information criterion model selection to assess the possible influence of log₁₀ area, isolation, and island group (two subarchipelagos) on the species richness of bats. We compared the species richness of bats on islands with greater vegetation densities in the southern gulf (n = 20) with that on drier islands with less vegetation in the northern gulf (n = 12) to investigate the relationship between habitat diversity and the species richness of bats. Results Twelve species of bats were detected on islands in the Gulf of California, and 15 species were detected in coastal habitats on the Baja peninsula. Bat species richness was related to both area and isolation of islands, and was higher in the southern subarchipelago, which has denser vegetation. Log₁₀ area was positively related to bat species richness, which increased by one species for every 5.4‐fold increase in island area. On average, richness declined by one species per 6.25 km increase in isolation from the Baja peninsula. Main conclusions Our results demonstrate that patterns of bat species richness in a near‐shore archipelago are consistent with patterns predicted by the equilibrium theory of island biogeography. Despite their vagility, bats may be more sensitive to moderate levels of isolation than previously expected in near‐shore archipelagos. Differences in vegetation and habitat xericity appear to be associated with richness of bat communities in this desert ecosystem. Although observed patterns of species richness were consistent with those predicted by the equilibrium theory, similar relationships between species richness and size and isolation of islands may arise from patch‐use decision making by individuals (optimal foraging strategies).     

Seed dispersal in the dung of large herbivores: implications for restoration of Renosterveld shrubland old fields

Species-rich, winter-rainfall, microphyllous Renosterveld vegetation in the Western Cape Province of South Africa has largely been transformed for production of wheat and wine. Remaining fragments thus have high conservation value. Abandoned old fields adjacent to natural vegetation fragments could potentially be restored as corridors and habitat for indigenous flora and fauna. We hypothesised that indigenous antelope maintained in a matrix of natural vegetation and abandoned field could play a role in restoration of Renoserveld via seed dispersal.We collected dung of indigenous ungulates in an abandoned field at various distances from natural Renosterveld vegetation, in order to assess the potential of large herbivores to contribute to restoration of plant diversity through seed dispersal. Emerged seedlings from the collected dung represented 29 forb, 13 grass, four sedge, four geophyte and one shrub species. The most abundant emerging seedlings were lawn grass Cynodon dactylon (38%), alien pasture grasses (31%) and indigenous geophyte Romulea rosea (12%). Whereas seeds of annual forbs and grasses were dispersed, only one shrub species was dispersed at very low density. We concluded that large herbivores could retard the rate of recovery of Renosterveld vegetation because viable seeds of herbaceous plants, particularly alien annual grasses and lawn-grasses were more abundant in the dung than the shrub, geophyte or perennial tussock grass species that characterise this vegetation type.     

Positive range–abundance relationships in Indo‐Pacific bird communities

Reeve et al. (2016, Ecography, 39 , 990–997) recently reported negative range–abundance relationships in Indo‐Pacific bird communities and speculated that geographical isolation facilitates the evolution of broad‐niched, small‐ranged and abundant species. We tested this relationship using a large independent data set on range and abundance of birds across New Caledonia (over 4,000 bird census points for 17,300 km²). In contradiction to Reeve et al. (2016, Ecography, 39 , 990–997), we found clear evidence that range–abundance relationships are positive and endemic species have narrower habitat niches than wide‐range species. Our findings are likely valid also for other islands in the Indo‐Pacific.     

Parallel habitat specialization within the wolf spider genus Hogna from the Galápagos

Within most island archipelagos, such as the Galápagos, similar ecological gradients are found on geographically isolated islands. Species radiations in response to these ecological gradients may follow different scenarios being (i) a single habitat specialization event followed by secondary colonization of each ecotype on the different islands or (ii) repeated and parallel habitat specialization on each island separately. This latter scenario has been considered less likely as gene flow might hamper such ecotypic differentiation. At least for the Galápagos, the extent to which this process is involved in species radiations remains yet poorly understood. Within the wolf spider genus Hogna, seven species are described that can be divided into three different ecotypes based on general morphology and habitat preference i.e. species that inhabit the pampa vegetation in the highlands, species that occur in coastal dry habitats and one generalist species. Comparison of the species phylogeny based on one mitochondrial (COI) and one nuclear (28S) gene fragment convincingly demonstrates that ‘pampa’ and ‘coastal dry’ species evolved in parallel on the islands Santa Cruz and San Cristóbal. Despite the observation that allozymes analysis indicated that each species forms a distinct genetic cluster, phylogenetic divergence within these species complexes was very low and paraphyletic and most likely due to hybridization rather than incomplete lineage sorting, as demonstrated for the Santa Cruz species complex. This suggests that within‐island speciation occurred under low levels of gene flow. Species phylogeny in general did not follow the progression of island emergence as a molecular clock analysis suggested that island endemic species may have diverged after as well as before the emergence of the islands. This represents the first clear example of parallel and within‐island speciation because of habitat specialization on the Galápagos and that such divergence most likely occurred under historic gene flow.     

Directional growth of a clonal bromeliad species in response to spatial habitat heterogeneity

Habitat selection by directional growth of plants has previously been investigated but field evidence for this phenomenon is extremely scarce. In this study we demonstrate directional clonal growth in Aechmea nudicaulis, a monocarpic, perennial bromeliad native to spatially heterogeneous sandy coastal plains (restinga) in Brazil. This habitat is characterized by a matrix of bare sand with interspersed vegetation islands. Due to very high soil surface temperatures and other stress factors such as drought, A. nudicauliscan only germinate inside vegetation islands. Nevertheless, this species is very common on bare sand. In this study we tested the hypothesis that clonal fragments occurring at the border and inside vegetation islands show habitat selection by growing preferentially towards the bare sand habitat (i.e. away from the center of vegetation islands).We randomly chose 116 clonal fragments in two distinct micro-environments (inside vegetation islands, and in the border area between bare sand and vegetation islands) in the natural habitat of A.nudicaulisand measured their growth direction in relation to the island center. We measured the growth directions of entire clonal fragments (defined as the line that connects the oldest and the youngest ramets of a clonal fragment) as well as the growth direction of the youngest internode on each fragment (the growth direction of the youngest ramet in relation to its parent ramet). We used Monte Carlo simulations to test for deviations from randomness in the growth direction of clonal fragments and individual internodes. The clonal fragments of A.nudicaulis showed a significant tendency to grow away from the center of vegetation islands. In other words, the main growth direction of clonal fragments growing inside vegetation islands or at the border between bare sand and vegetation islands was preferentially directed towards bare sand environments. Individual internodes at the border of vegetation islands also exhibited this tendency to grow towards the outside of vegetation islands, but internodes growing inside vegetation islands did not show directional growth. These results provide the first field evidence for habitat selection through directional growth of a clonal plant species.Co-ordinationg editor: J. Tuomi     

Why do some small islands lack vegetation? Evidence from long‐term introduction experiments

Classic island biogeography theory predicts that very small islands, near the extreme lower end of the species–area relationship, should support very few species. At times no species may be present, however, due to randomness in the immigration–extinction dynamics. Alternatively, a lack of vegetation on very small islands may indicate that such islands do not contain the appropriate habitat for the establishment or long‐term survival of plants, or that disturbances are too frequent or intense. These potential mechanisms were evaluated in the central Exumas, Bahamas, where surveys of 117 small islands revealed that over a third of the islands supported no terrestrial plant life. Area and exposure were significant predictors of whether a small island was vegetated or not in multiple logistic regressions. No islands naturally devoid of vegetation were colonized over a 17‐yr period, and only two naturally vegetated islands lost all vegetation. Experimental introductions of two species –Sesuvium portulacastrum and Borrichia arborescens– revealed that a number of islands naturally lacking vegetation were able to sustain introduced populations over the long term (up to 15 yr). Drought and hurricanes appeared to have reduced the establishment success and possibly long‐term survival of the introductions, although some populations survived four major hurricanes. Turnover rates of both introduced species were often an order of magnitude higher on the experimental introduction islands than on other islands in the archipelago. It appears many of the islands in this system that naturally lack vegetation may be physically capable of supporting terrestrial plant life, yet have no plants primarily due to barriers to colonization.     

Vole–vegetation interactions in an experimental, enemy free taiga floor system

Vole–vegetation interactions in a predation‐free taiga environment of northern Fennoscandia were studied by transferring vegetation from natural Microtus habitats into a greenhouse, where three habitat islands of about 30 m² were created. The ‘islands’ were subjected to simulated summer conditions and a paired female field vole, Microtusagrestis, was introduced to each ‘island’. The development of the female and her young was followed by recurrent live trapping. The development of the vegetation was followed by recurrent marking and censusing of plant shoots at intervals of five days. In the next growing season, two ‘islands’ were subjected to a new grazing treatment to study the impacts of repeated grazing on the vegetation and on the growth and reproduction of voles. Plant biomasses were harvested at the end of each trial. In all trials, the biomasses of graminoids and non‐toxic herbs other than ferns, fireweeds and rosaceous plants were profoundly decimated. Even the biomass of a toxic herb Aconitum lycoctonum decreased largely at pace with the palatable herbs. The least preferred plant categories maintained their biomasses at control levels. Their neutral collective response was created by opposite species‐level trends. Species typical for moist and nutrient‐rich forests suffered from vole grazing, whereas the biomass of species adapted to disturbed habitats increased. In spite of the dramatic changes in the vegetation, the introduced female voles survived throughout the trials and reproduced normally. The young of their first litters survived well and reached the final weights typical for individuals starting to winter as immatures. We conclude that most of the plant biomass found on productive boreal forest floors is potential food for field voles and remains palatable for them even when subjected to recurrent, severe grazing. If nothing else than summer resources were limiting the growth of the field vole populations, the plants currently dominating moist and nutrient‐rich taiga floors could not survive in this habitat.     

Vegetation structure and ground cover attributes describe the occurrence of a newly discovered carnivorous marsupial on the Tweed Shield Volcano caldera,the endangered black‐tailed dusky antechinus (Antechinus arktos)

The black‐tailed dusky antechinus (Antechinus arktos) is a recently discovered, endangered, carnivorous marsupial mammal endemic to the Tweed Shield Volcano caldera, straddling the border between Queensland and New South Wales in eastern Australia. The species' preference for cool, high‐altitude habitats makes it particularly vulnerable to a shifting climate as these habitats recede. Aside from basic breeding and dietary patterns, the species' ecology is largely unknown. Understanding fine‐scale habitat attributes preferred by this endangered mammal is critical to employ successful conservation management. Here, we assess vegetation attributes of known habitats over three sites at Springbrook and Border Ranges National Parks, including detailed structure data and broad floristic assessment. Floristic compositional assessment of the high‐altitude cloud rainforest indicated broad similarities. However, only 22% of plant species were shared between all sites indicating a high level of local endemism. This suggests a diverse assemblage of vegetation across A. arktos habitats. Habitat characteristics were related to capture records of A. arktos to determine potential fine‐scale structural habitat requirements. Percentage of rock cover and leaf litter were the strongest predictors of A. arktos captures across survey sites, suggesting a need for foraging substrate and cover. Habitat characteristics described here will inform predictive species distribution models of this federally endangered species and are applicable to other mammal conservation programs.     

Predicting growth of mat‐forming lichens on a landscape scale – comparing models with different complexities

During the 20th century, forestry practices has adversely affected lichen‐rich habitats. Mat‐forming lichens are important components of the vegetation of boreal and arctic ecosystems and are the main reindeer forage during the winter. To support the long‐term management of lichens in such habitats we developed models for predicting the growth of two common species. The lichens were transplanted across northern Scandinavia along a west‐east gradient varying in precipitation, temperature and irradiance. Growth was recorded seasonally over 16 months and ranged from ?4.8 to 34.6% and ?12.7 to 34.7% dry weight change for Cetraria stellaris and Cladina islandica, respectively. Growth was light limited below canopies with more than ca 60% cover and highest at the more humid sites when light levels were optimal. The models were based on various meteorological parameters, irradiance, physiological data and lichen hydration status; the latter was derived from a recently developed lichen hydration model. Our models' abilities to predict growth, both annually and seasonally (i.e. in summer), were evaluated in relation to their complexity and their potential usefulness from a management perspective. One parameter related to irradiance (the logarithm of site openness) was valuable in the prediction of annual growth for both species and could, in combination with precipitation, explain 52% of the variation in annual growth for C. stellaris and, in combination with total wet time and the irradiance received while wet, explain 66% of the variation in annual growth for C. islandica. The best simplified model explained 43% of the variation in annual growth for C. stellaris, using stem basal area and the annual normal temperature, and 24% for C. islandica using basal area alone. It is concluded that ensuring sufficient irradiance below the forest canopy is of crucial importance in the long‐term management of mat‐forming lichens and that simplified models can be used to identify appropriate habitats.     

Habitat preference in the critically endangered yellow‐tailed woolly monkey (Lagothrix flavicauda) at La Esperanza,Peru

Habitat loss is one of the main threats to wildlife. Therefore, knowledge of habitat use and preference is essential for the design of conservation strategies and identification of priority sites for the protection of endangered species. The yellow‐tailed woolly monkey (Lagothrix flavicauda Humboldt, 1812), categorized as Critically Endangered on the IUCN Red List, is endemic to montane forests in northern Peru where its habitat is greatly threatened. We assessed how habitat use and preference in L. flavicauda are linked to forest structure and composition. The study took place near La Esperanza, in the Amazonas region, Peru. Our objective was to identify characteristics of habitat most utilized by L. flavicauda to provide information that will be useful for the selection of priority sites for conservation measures. Using presence records collected from May 2013 to February 2014 for one group of L. flavicauda, we classified the study site into three different use zones: low‐use, medium‐use, and high‐use. We assessed forest structure and composition for all use zones using 0.1 ha Gentry vegetation transects. Results show high levels of variation in plant species composition across the three use zones. Plants used as food resources had considerably greater density, dominance, and ecological importance in high‐use zones. High‐use zones presented similar structure to medium‐ and low‐use zones; thus it remains difficult to assess the influence of forest structure on habitat preference. We recommend focusing conservation efforts on areas with a similar floristic composition to the high‐use zones recorded in this study and suggest utilizing key alimentation species for reforestation efforts.