Using habitat models to determine conservation priorities for pond-breeding amphibians in a privately-owned landscape of northern Idaho, USA

As rural landscapes experience increasing levels of residential development, the persistence of species that rely on them will depend on informed planning and management decisions. An understanding of habitat requirements is essential for setting priorities and developing landscape-level plans for the survival of these species. In many temperate rural landscapes, artificially created ponds may be the only wetlands available for aquatic reproduction by amphibians. The introduction of non-native fish into these ponds reduces survival and prohibits successful reproduction of many native pond-breeding amphibians. We surveyed 105 randomly selected wetlands in a primarily privately-owned, rural landscape in north Idaho, USA, for pond-breeding amphibian larvae in 2004 and 2005. We used an information theoretic multimodel inference and an algorithmic (random forests) approach to model habitat for each species based on local and landscape characteristics. We also used a mail survey to quantify how landowners value fish in their wetlands and their plans for future wetland development and fish stocking. Sixty-seven percent of pond owners reported that fishing in their pond was at least slightly important to them and 36% of owners indicated that they were at least 50% likely to add fish to their ponds in the next 5-10 years. Landscape change predictions for this area indicate that forests will become more open due to thinning; habitat models indicated that this is likely to be detrimental to long-toed salamanders and beneficial to Pacific treefrogs. Habitat models also indicate that Columbia spotted frog breeding sites consist of wetlands on flat ground with high solar insolation and that this species is sensitive to nearby development, indicating that as this landscape becomes further developed, this species may require habitat protection for persistence.     

From the micro-scale to the habitat: Assessment of soil bacterial community structure as shown by soil structure directed sampling

Natural structural units of a luvisol under maize crop were studied to assess if soil structure directed sampling could improve the understanding of arrangements of bacteria in spatially constraint location. Three habitats were defined: (i) soil around fine lateral roots (rhizo-aggregates), (ii) soil close to basal roots (core clods) and (iii) unplanted soil between rows (bare soil clods). These habitats were also investigated with maize plants resulting from Azospirillum lipoferum CRT1 inoculated seeds as a model of enhanced fine root system. Rhizo-aggregates were clearly separated from each other (disconnected habitat) in contrast to micro-samples (fragments) from clods, which belong to cohesive macro-structures. Genetic fingerprints on metagenomic extracts were used to characterize the structure of bacterial communities on 95 micro-samples from the three habitats. For eubacteria, automated RISA (Ribosomal Intergenic Spacer Analysis) of ITS (Internal Transcribed Spacer) profiles were performed. PCR-RFLP on nifH gene were used to describe the N-fixer guilds. Exploratory multivariate analyses (PCA and MDS) revealed bacterial community patterns in the sampled habitats. On the basis of ITS profiles, rhizo-aggregates harboured closely related communities, distant from those of the unplanted soil, and each sampled rhizo-aggregate could therefore be considered as a sub-unit of the whole macro-habitat, comprising all the fine roots. The observed low dissimilarity of disconnected rhizo-aggregates is likely to result from the direct influence of maize root tips on the recruitment of rhizosphere bacteria. Molecular fingerprints of nifH from basal root clods (core) were more similar to bare soil than to rhizo-aggregates, indicating similar ecological conditions without, or with, at least, poor maize exudating root influence. Although our study was performed on a limited number of situations, the distribution of bacteria was revealed to be patterned by soil structure units, which is a first step to improve the modelling of microbial ecology in soils.     

Inferring habitat-suitability areas with ecological modelling techniques and GIS: A contribution to assess the conservation status of Vipera latastei

Some snakes are highly vulnerable to extinction due to several life history traits. However, the elusive behavior and secretive habits of some widespread species constrain the collection of demographic and ecological data necessary for the identification of extinction-prone species. In this scenario, the enhancement of ecological modelling techniques in Geographical Information Systems (GIS) is providing researchers with robust tools to apply to such species. This study has identified the environmental factors that limit the current distribution of Vipera latastei, a species with secretive behavior, and has evaluated how human activities affect its current conservation status, identifying areas of best habitat suitability in the Iberian Peninsula. Ecological-niche factor analysis (ENFA) indicated low marginality (0.299) and high tolerance (0.887) scores, suggesting strong tendency for the species to live in average conditions throughout the study area and to inhabit any of the environmental conditions. The analysis also revealed that this viper tends to select particular Mediterranean habitats, although topographic factors (altitude and slope) were the major environmental constraints for the Iberian distribution pattern of the species. The presence of other parapatric viper species in the north of the Iberian Peninsula (V. aspis and V. seoanei) and two human-related variables (landscape transformation and human density) also had a negative relation with the occurrence of V. latastei. All factors can explain its absence in northern Iberia and its fragmented distribution as currently is found mostly in mountains and relatively undisturbed low-altitude areas. The historical destruction and alteration of natural Mediterranean habitats and several life-history traits of the species contribute to its vulnerability to extinction. The ENFA analysis proved to be an outstanding method to evaluate the factors that limit the distribution range of secretive and widespread species such as V. latastei, updating evaluation of their conservation status.     

An alternative to dolphin oil as a fish attractant in the Ganges River system: conservation of the Ganges River dolphin

Oil extracted from blubber of the Ganges River dolphin, Platanista gangetica, is used as a fish attractant in India and Bangladesh. This oil fishery is associated with the mortality of hundreds of dolphins every year. Oil from fish scraps was field tested for 121 days during 1997-1999 in the Ganges at Patna and was a very effective alternative to dolphin oil as a fish attractant. Fishing with fish oil resulted in higher catches and greater income per person per hour (Rs. 17.8±12.5) than fishing with dolphin oil (Rs. 11.6±9.3). However, there is no statistically significant difference between the results from fishing with dolphin and fish oil. Oil from fish scraps is inexpensive and can be made readily available to all the fishermen. Its widespread use would help in conserving the endangered Ganges River dolphin.     

Effects of increased salinity and an introduced predator on lowland amphibians in Southern China: Species identity matters

Approximately 30% of amphibian species are threatened due to a variety of factors affecting their habitats and physiology, yet contributions that interactions among factors make to population declines are not well-explored. Two factors, introduced mosquitofish (Gambusia affinis) and increased salinity, may coincide in lowland habitats used by breeding amphibians. Mosquitofish have been introduced worldwide and can be significant predators of amphibian larvae. Salinization of wetlands is an increasing problem globally due to (1) application of road deicing salts in temperate regions, (2) irrigation practices associated with intensive agriculture, and (3) saltwater intrusion due to sea-level rise. We investigated the effects of mosquitofish (G. affinis) and increasing salinity on five species of lowland wetland-breeding amphibians from southern China. We exposed anuran hatchlings to four salinity levels and two fish treatments and all combinations of the two factors in a series of experiments. Four of the species were susceptible to predation by mosquitofish, two were sensitive to increased salinity at concentrations >6% seawater, and one was tolerant of both increased salinity and mosquitofish. We found no interaction between the predator and increased salinity. Salinization and mosquitofish represent significant threats to lowland amphibians in this region and, coupled with the ongoing loss and degradation of lowland wetlands, portend a bleak future for lowland amphibian populations in the region.     

Proportion of individuals with anti-Batrachochytrium dendrobatidis skin bacteria is associated with population persistence in the frog Rana muscosa

The emergence of the infectious disease chytridiomycosis is a major factor responsible for amphibian extinctions in pristine habitats. However, some populations coexist with Batrachochytrium dendrobatidis (Bd), the agent of chytridiomycosis, and others go extinct when Bd arrives. Variation of pathogen severity among populations may be explained by differences of antimicrobial skin peptides and anti-Bd skin bacteria. Previous work showed that a population of the frog Rana sierrae had a high proportion of individuals with at least one species of cultured anti-Bd skin bacteria and was coexisting with Bd for more than 6 years. A population of the closely related sister species Rana muscosa had a significantly lower proportion of individuals with anti-Bd bacteria, and the following year, it went extinct due to Bd. We extended previous work to include another sampling of the R. sierrae population coexisting with Bd and found that, although the anti-Bd bacterial community somewhat differed, both populations had a high proportion of individuals with antifungal bacteria. We also included a population of R. muscosa that was naïve of Bd and predicted to go extinct once Bd emerged since that was the fate of neighboring populations. However, the naïve R. muscosa population had a high proportion of antifungal bacteria, which suggested that the population might survive if Bd emerged. Two years later, the population was surviving with Bd endemic. Variation in the proportion of individuals with anti-Bd skin bacteria appears to explain why some populations persist when Bd emerges in a population.     

Does the matrix matter? A forest primate in a complex agricultural landscape

Many threatened primates now exist in fragmented forest habitats. The survival of these populations may depend on their ability to utilise agricultural or other matrix habitats between forest fragments, but this is poorly known. Here, we systematically investigate an arboreal primate’s use of a heterogeneous matrix in a fragmented forest landscape: the Angola black-and-white colobus (Colobus angolensis palliatus) in southern Kenya. We used a novel technique, based on semi-structured interviews with local informants, to address the difficulty of sampling relatively rare but important events, such as dispersal between fragments. We found that colobus frequently travelled and foraged in indigenous matrix vegetation (such as mangrove, wooded shrubland and shrubland) up to 4 km from the nearest forest fragments. Agricultural habitats, such as perennial plantation (coconut, mango and cashew nut) were also used by colobus for travelling and foraging (in remnant indigenous trees). The probability of sighting colobus in the matrix increased with the proportion of both tall (>6 m) vegetation cover and food tree cover, but declined with distance from forest habitat. Our findings suggest that certain matrix habitats are important for C. a. palliatus, and that future primate conservation initiatives might benefit from adopting a ‘landscape-level’ approach to habitat management, particularly in fragmented forest systems.     

The recent decline of a New Zealand endemic: how and why did populations of Archey's frog Leiopelma archeyi crash over 1996-2001?

Dramatic changes have been documented in New Zealand's vertebrate faunas since human settlement, involving major declines and extinctions, but over recent years few species have declined in numbers so rapidly as the terrestrial Archey's frog Leiopelma archeyi (Anura: Leiopelmatidae). Long-term monitoring over more than 20 years revealed a major population reduction of the species over 1996-2001 and L. archeyi is now classified as Nationally Critical under the New Zealand threat classification system. The decline progressed northwards in the Coromandel ranges, and mostly larger (female) frogs survived. On a 100 m² study plot at Tapu Ridge, annual population estimates averaged 433 frogs (SE ±32) over 1984-1994, declining by 88% to average 53 frogs (SE ±8) over 1996-2002. A mean annual survival rate of 82% for most years declined to 33% over 1994-1997. There is mounting evidence to suggest that disease is the major agent of decline, supported by (1) the rapidity and severity of decline, (2) the progressive (south to north) nature of decline, and (3) finding frogs with chytriodiomycosis from Batrachochytrium dendrobatidis at the time of decline. Surprisingly, sympatric populations of the semi-aquatic Leiopelma hochstetteri have not declined dramatically, nor has a western population of L. archeyi at Whareorino, despite chytridiomycosis occurring in some frogs there. Sustaining and restoring populations of L. archeyi in New Zealand raises major challenges for conservation management.     

Location of roosts of the lesser long-eared bat Nyctophilus geoffroyi and Gould's wattled bat Chalinolobus gouldii in a fragmented landscape in south-eastern Australia

The location of roosts of two species of vespertilionid bats, the lesser long-eared bat (Nyctophilus geoffroyi) and Gould’s wattled bat (Chalinolobus gouldii), was investigated in a remnant vegetation-farmland mosaic and adjacent floodplain forest in south-eastern Australia. A total of 45 individuals of N. geoffroyi and 27 C. gouldii were fitted with radio transmitters, which resulted in the location of 139 and 89 roosts respectively. Selection of roosting habitat showed both inter- and intra-specific differences. At the landscape level, locations of roosts used by male and female N. geoffroyi differed markedly. Most males roosted in the farmland mosaic within 3 km (mean 1.9±2.9 km) of where they were captured while foraging in remnant vegetation. In contrast, roost sites of females were predominantly in the floodplain forest, 6-12 km from their capture site in farmland (mean for all females, 6.7±2.9 km). All maternity roosts were in the extensive floodplain forest, 4-10 km from foraging areas. Distances moved by this species were greater than previously recorded and further than predicted by flight morphology. Most C. gouldii roosted in the floodplain forest, 4-10 km from their capture site (6.9±1.6 km). Within the floodplain forest, both species roosted in areas that had higher densities of hollow-bearing trees than generally available; dead hollow-bearing trees for N. geoffroyi and large, live trees for C. gouldii. The scale of movements undertaken by these species means that they can obtain resources from multiple landscape elements. Both species used different habitats for roosting and foraging despite the energetic costs of commuting relatively large distances. Conservation of bat populations in rural environments needs to be considered at the landscape scale, with particular attention to identifying landscape elements that provide key resources.     

Subtle changes in rhizosphere microbial community structure in response to increased boron and sodium chloride concentrations

Two of the major constraints to grain production in large areas of South-East Australia and cropping soils worldwide are high levels of subsoil boron (B) and excessive salinity (NaCl). Although the effect of these constraints is often studied in plants, the effect on microbially mediated plant-beneficial processes is unclear. To that end, we investigated the impact of B and NaCl on soil microbial community structure (MCS) in the wheat rhizosphere using BIOLOG ecoplates and terminal restriction fragment length polymorphism (T-RFLP). In addition, the effects of B and NaCl on the nitrogen (N) cycle processes of N fixation and ammonia oxidation were assessed by the construction of clone libraries of diazotrophic (nifH) and ammonia oxidising (amoA) rhizobacteria. Analysis of BIOLOG plates using non-metric multidimensional scaling (MDS) revealed addition of both B and NaCl significantly changed MCS, the latter of which was also significant through the analysis of T-RFLP data. Utilisation of several chemical groups of BIOLOG substrates significantly changed in NaCl-amended soil; both B and NaCl affected utilisation of several individual substrates indicative of plant stress including serine and malic acid. A significant decrease in diversity and species richness was observed in high B rhizosphere soil. The community structure of ammonia-oxidising bacteria (AOB), all of which clustered with Nitrosospira-like sequences, did not significantly change in response to addition of B or NaCl, but addition of the latter resulted in a significant increase of diazotroph clones within the α-proteobacteria similar to Azospirillum sp. It appeared that the addition of B and NaCl to soil changed rhizosphere MCS indirectly through increased soil moisture and subtle changes in root exudate patterns, the addition of the latter producing a more distinct change through increased osmotic pressure, leading to a greater increase in rhizodeposition of nutrients, especially carbohydrates. The implications for the current study are that B and NaCl are more likely to affect rhizosphere MCS indirectly through root exudate quantity and/or quality than directly through microbial toxicity, and that plant health is a major determinant in rhizosphere MCS and normal N cycling.     

Grasslands as movement barriers for a forest-associated salamander: Migration behavior of adult and juvenile salamanders at a distinct habitat edge

The persistence of amphibian populations in fragmented landscapes requires dispersal and recolonization of habitat patches after local extinction. These processes entail individuals crossing habitat edges. Edge permeability integrates the behavior of individuals with the vegetative structure of the habitat edge and may influence the dispersal rates between habitat patches. We used drift fences, radio telemetry, and an experimental displacement to examine the movement behavior of juvenile and adult spotted salamanders (Ambystoma maculatum) at a pond located in continuous forest and a pond located on a distinct forest-grassland edge. At the pond on the habitat edge, adult salamanders migrated to and from the forested side of the pond. Resident adults with transmitters migrated to forested habitat without approaching the habitat edge. Displaced adults with transmitters halted emigration movements when they approached the habitat edge. None of the radio-tagged adults were observed more than a few meters into the grassland. Recently metamorphosed juveniles exiting the grassland side of the pond changed their direction of movement and migrated into the forested habitat. We conclude that salamanders oriented movements with respect to features in the terrestrial habitat, detected the habitat edge, and behaviorally avoided the grassland. Exploring the permeability of habitat edges will improve our understanding of dispersal within fragmented landscapes and enhance efforts to conserve regional populations of amphibians.     

Litter type, but not plant cover, regulates initial litter decomposition and fungal community structure in a recolonising cutover peatland

Cutover peatlands are often rapidly colonised by pioneer plant species, which have the potential to affect key ecosystem processes such as carbon (C) turnover. The aim of this study was to investigate how plant cover and litter type affect fungal community structure and litter decomposition in a cutover peatland. Intact cores containing Eriophorum vaginatum, Eriophorum angustifolium, Calluna vulgaris and bare soil were removed and a mesh bag with litter from only one of each of these species or fragments of the moss Sphagnum auriculatum was added to each core in a factorial design. The presence or absence of live plants, regardless of the species, had no effect on mass loss, C, nitrogen (N) or phosphorus (P) concentrations of the litter following 12 months of incubation. However, there was a very strong effect of litter type on mass loss and concentrations of C, N and P between most combinations of litter. Similarly, plant species did not affect fungal community structure but litter type had a strong effect, with significant differences between most pairs of litter types. The data suggest that labile C inputs via rhizodeposition from a range of plant functional types that have colonised cutover bogs for 10-15 years have little direct effect on nutrient turnover from plant litter and in shaping litter fungal community structure. In contrast, the chemistry of the litter they produce has much stronger and varied effects on decomposition and fungal community composition. Thus it appears that there is distinct niche differentiation between the fungal communities involved in turnover of litter versus rhizodeposits in the early phases of plant succession on regenerating cutover peatlands.     

The genetic structure of coastal giant salamanders (Dicamptodon tenebrosus) in a managed forest

The salamander, Dicamptodon tenebrosus, is threatened by habitat loss and fragmentation associated with forest harvest activities. We used three microsatellite loci and 38 amplified fragment length polymorphisms (AFLPs) to quantify population structure and indirectly evaluate the impacts of forest harvesting on this species. We sampled two old growth sites, three second growth sites and three recently clearcut sites in British Columbia, Canada. Microsatellite allelic richness and the percentage of polymorphic AFLPs were positively correlated with the age of forest stands. Similarly, heterozygosity estimated from both marker types was positively correlated with stand age. Population subdivision (F_st) estimated among forested sites using microsatellite and AFLP markers was 0.033 and 0.095, respectively. Lower genetic variation and heterozygosity in recent clearcuts suggest that clearcut logging may be associated with local population declines. Our genetic findings are consistent with previous studies that report lower salamander densities in recently clearcut sites.     

Recent, substantial, and unexplained declines of the common toad Bufo bufo in lowland England

A decline in numbers of a large common toad (Bufo bufo) population in south-east England during the 1990s, together with anecdotal reports of similar trends in other toad populations, prompted a nation-wide survey of this species. The survey also included the common frog (Rana temporaria) as a control for which there was no comparable evidence of recent decline. A questionnaire requesting information on the fate of toad and frog populations in the last 15 years of the 20th century was distributed to professional and amateur herpetologists during autumn 2001. Ninety-five respondents provided data on a total of 277 sites, including 232 frog and 202 toad populations in England, Scotland and Wales. More than 80% of the reported sites were rural for both species. Rural frog populations were generally doing well in most parts of Britain, with almost as many increasing as decreasing populations and a high proportion of stable populations. Rural toads also showed no overall trend across the country as a whole. However, regional analysis indicated that although toads were faring at least as well as frogs in the north and west of Britain, they were declining seriously in central and eastern/south-eastern areas. In these regions 50% or more of toad populations have experienced recent declines, whereas frogs have fared as well as they have elsewhere. Toads breeding alone have fared significantly worse than toads breeding at sites where frogs were also present. Reasons for apparently toad-specific declines in lowland England remain unknown.     

Population structure and movements of a threatened butterfly (Lopinga achine) in a fragmented landscape in Sweden

The red-listed butterfly Lopinga achine was studied by mark-recapture methods in southern Sweden for three seasons. We examined movement within and between populations and egg production in relation to age. The majority of the movements were small with mean movements between recaptures of 45-54 m for males and 94-116 m for females. There were few movements between sites, 20 of 996 recaptured males moved and 36 of 391 recaptured females, even though the distance to other sites was in many cases <100 m. The distance moved and the number of females moving between sites increased with increasing age. On average, a female that moves does so after laying two-thirds of its eggs in its natal site. It is therefore important to take account of the proportion of reproductive effort involved in dispersal when estimating colonisation ability. The males did not move more with increasing age. Female behaviour can be seen as a “spread-the-risk” strategy, an adaptation to the successional habitat of L. achine, whose natal site sooner or later will deteriorate. Butterflies like L. achine living in successional habitats may exhibit mobility that is intermediate between butterflies living in ephemeral habitats (very mobile) and in long-lived habitats (sedentary).     

Fungal growth on a common wood substrate across a tropical elevation gradient: Temperature sensitivity, community composition, and potential for above-ground decomposition

Fungal breakdown of plant material rich in lignin and cellulose (i.e. lignocellulose) is of central importance to terrestrial carbon (C) cycling due to the abundance of lignocellulose above and below-ground. Fungal growth on lignocellulose is particularly influential in tropical forests, as woody debris and plant litter contain between 50% and 75% lignocellulose by weight, and can account for 20% of the C stored in these ecosystems. In this study, we evaluated factors affecting fungal growth on a common wood substrate along a wet tropical elevation gradient in the Peruvian Andes. We had three objectives: 1) to determine the temperature sensitivity of fungal growth - i.e. Q₁₀, the factor by which fungal biomass increases given a 10 °C temperature increase; 2) to assess the potential for above-ground fungal colonization and growth on lignocellulose in a wet tropical forest; and 3) to characterize the community composition of fungal wood decomposers across the elevation gradient. We found that fungal growth had a Q₁₀ of 3.93 (95% CI of 2.76-5.61), indicating that fungal biomass accumulation on the wood substrate nearly quadrupled with a 10 °C increase in temperature. The Q₁₀ for fungal growth on wood at our site is higher than Q₁₀ values reported for litter decomposition in other tropical forests. Moreover, we found that above-ground fungal growth on the wood substrate ranged between 37% and 50% of that measured in the soil, suggesting above-ground breakdown of lignocellulose represents an unexplored component of the C cycle in wet tropical forests. Fungal community composition also changed significantly along the elevation gradient, and Ascomycota were the dominant wood decomposers at all elevations. Fungal richness did not change significantly with elevation, directly contrasting with diversity patterns observed for plant and animal taxa across this gradient. Significant variation in fungal community composition across the gradient suggests that the characteristics of fungal decomposer communities are, directly or indirectly, influenced by temperature.     

Butterfly distribution and abundance is affected by variation in the Swedish forest-farmland landscape

Remaining patches of semi-natural grasslands are hot spots for biodiversity in modern agricultural landscapes. In Sweden semi-natural pastures cover approximately 500,000 ha. However, power-line corridors, road verges and clear-cuts cover larger areas (in total about 2,000,000 ha), and these open, less intensively managed habitats are potentially important for species associated with taller vegetation and flower resources (e.g. pollinating insects). The aim of the present study was to evaluate the relative importance of semi-natural pastures and the other three open habitats for butterflies in 12 forest-farmland mosaic landscapes in south central Sweden. Species composition differed significantly between habitats in multivariate analyses. Power-line corridors and semi-natural pastures harbored several species that were disproportionally abundant in these habitats (13 and 8 species, respectively), and power-line corridors also harbored several species that were classified as typical in indicator species analyses. There were more butterfly species, higher abundances and a tendency for more individuals of red-listed species in power-line corridors than in the other three habitats. Effects of the surrounding landscape composition seemed to be weaker than that of the local habitat. However, species composition was significantly associated with landscape composition and species with intermediate and low mobility were more abundant in forested landscapes than in landscapes dominated by arable fields. Analyses of flying time and host plants for larvae suggest that early flying species and species associated with dwarf shrubs were more common in power-line corridors than in the other habitats. A landscape perspective, which takes several habitats into account, is needed for conservation of butterfly communities in forest-farmland landscapes. Power-line corridors and road verges offer possibilities for creating habitats that are suitable for pollinating insects through conservation-oriented management.     

Spring bryophytes in forested landscapes: Land use effects on bryophyte species richness, community structure and persistence

Many freshwater ecosystems face severe threats from anthropogenic disturbances, yet little is known about the degree to which their biotic communities have been degraded by human activities. We analysed temporal changes and persistence of bryophyte communities in 40 springs in eastern Finland by comparing field surveys conducted in 1986 and 2000. During that period, some springs had remained in a near-pristine state, while others had undergone varying degrees of disturbance from forest management, drainage, and water abstraction. Several spring bryophytes (e.g., Philonotis fontana) declined between the study years, whereas Sphagnum mosses (e.g., Sphagnum warnstorfii) increased in abundance. Species richness of spring bryophytes declined significantly from 1986 to 2000, irrespective of bryophyte group (spring vs. other bryophytes) and spring condition (severely disturbed vs. unaltered springs). Bryophyte cover also decreased dramatically from 1986 to 2000, but this effect was related to both spring condition and bryophyte type. Spring bryophytes lost much of their cover in severely altered springs, while in unaltered springs they remained relatively stable through time. No such trend was observed for other, habitat generalist bryophytes. Persistence and stability of bryophyte communities showed significant, albeit rather weak, relationships with spring condition, with communities in unaltered springs being more persistent than those in altered springs. Given the importance of springs to boreal forest and aquatic biodiversity, restoration of degraded springs is a major challenge to maintaining and conserving biodiversity of boreal landscapes.     

Role of human-modified habitat in protecting specialist species: A case study in the threatened Florida Scrub-Jay

Habitat specialists are especially vulnerable to habitat alterations in vegetation structure and composition, making them difficult to protect and restore amidst agricultural landscapes. Protection strategies in such cases require information on species’ ability to survive and reproduce on marginal and modified habitat. We examined reproductive success, survival, and foraging efficiency of the Florida Scrub-Jay (Aphelocoma coerulescens), an extreme habitat specialist, in a human-modified habitat - regenerating pasture - along a pasture-native scrub interface. From 1985 to 2003, Florida Scrub-Jays were equally successful at producing young in regenerating pasture and native scrub. Production of eggs, nestlings, fledglings, independent young, and yearlings were not statistically different between territories containing pasture and those containing only scrub. Similar trends were observed for nest success and survival. When in pasture, individual jays were significantly more efficient at capturing small prey items, but significantly less efficient at capturing medium and large prey items. Availability of small prey items was significantly higher in pasture than in scrub; availability of medium and large prey items was not significantly different between habitat types. We conclude that regenerating pasture provides suitable supplemental habitat for Florida Scrub-Jays when in close proximity to native scrub, suggesting a novel conservation strategy for maintaining and potentially increasing local populations in fragmented agricultural settings. This case study illustrates how a broadened definition of ‘suitable habitat’ may augment existing conservation strategies for specialist species facing substantial and rapid modification of their native habitat.