Development of microsatellite markers for Stachyurus macrocarpus and Stachyurus macrocarpus var. prunifolius (Stachyuraceae), critically endangered shrub species endemic to the Bonin Islands

Stachyurus macrocarpus and S. macrocarpus var. prunifolius are critically endangered shrub species in the Bonin (Ogasawara) Islands, Japan. These species are extremely rare, and the numbers of individuals in wild populations are 68 in S. macrocarpus and 13 in S. macrocarpus var. prunifolius. For the investigation of genetic diversity, genetic structure and relatedness among remnant individuals of these endangered species, we developed eight microsatellite markers from S. macrocarpus var. prunifolius and characterized these markers for S. macrocarpus var. prunifolius and S. macrocarpus using all naturally occurring individuals of these species. The expected heterozygosities of these markers ranged from 0.14 to 0.67 in S. macrocarpus var. prunifolius, and from 0.02 to 0.84 in S. macrocarpus. The markers described here will be useful for investigating the genetic diversity, genetic structure and relatedness among remnant individuals, and planning the restoration of these critically endangered species.     

Combined effects of seed and soil quality drive seedling performance of a late‐successional canopy tree in a tropical forest

Habitat loss and fragmentation affect the structure and functioning of forested ecosystems worldwide, yet we lack an understanding of how species respond to environmental changes. Here, we examined reproductive success and seedling performance of Poulsenia armata (Moraceae) in continuous and fragmented forests of Los Tuxtlas, southern Mexico. We further investigated how maternal habitat and soil conditions manifested in the seedling stage. We determined seed quality and seedling performance by combining isotopic analyses in seed quality with field observations of P. armata fruit production and a common‐‐garden experiment. Soil conditions in forest fragments negatively impacted P. armata reproductive success. Trees of P. armata in forest fragments were smaller in size and produced fewer fruits and smaller seeds with lower quality compared with trees from the continuous forest. The combined effects of maternal habitat and soil conditions determined seedling survival and growth of this tropical tree. Notably, seedlings had restricted plasticity for biomass allocation to roots, limiting the capacity of fragmented populations to compensate for the initial low N content in seeds. Trees in forest fragments at Los Tuxtlas produced offspring competitively inferior and potentially less resilient than counterparts in continuous forest, jeopardizing future persistence of this late‐successional tree species.     

Woody plants' diversity,structural analysis and regeneration status of Wof Washa natural forest,North‐east Ethiopia

Wof‐Washa forest is one of the few remaining dry Afromontane forests in the central plateau of Ethiopia. Woody species composition, structure and regeneration patterns of this forest were studied to generate information essential for formulating feasible management options for the forest. Vegetation data were collected from 64 quadrats of size 20 m × 20 m, 10 m × 10 m and 5 m × 5 m for tree/shrub, sapling and seedling, respectively, laid systematically along transects. A total of 62 woody species belonging to 54 genera and 40 families were recorded. Rosaceae was the most diverse family with five (12.5%) species followed by Anacardiaceae, Euphorbiaceae and Myrsinaceae with three (7.5%) species each. Tree/shrub, sapling and seedling densities were 699, 1178 and 7618.7 individuals/ha. About 56.7% of the importance value index was contributed by Juniperus procera, Maytenus arbutifolia, Podocarpus falcatus and Ilex mitis. Vegetation classification resulted in five plant communities: Ilex mitis – Maytenus obscura, Galiniera saxifraga – Maesa lanceolata, Juniperus procera – Erica arborea, Podocapus falcatus – Allophylus abyssinicus and Pittosporum viridiflorum – Polycias fulva community types. Regeneration status of all the woody plant species was categorized as ‘Good’ (28%), ‘Fair’ (19%), ‘Poor’ (8%), ‘None’ (40%) and ‘New’ (5%).     

Differences in bird communities in postfire silvicultural practices stands within pine forest of South Korea

We examined differences in bird communities in relation to characteristics of habitat structure in a pine forest, Samcheok, South Korea. An unburned stand, a stand burned 7 years earlier and then naturally restored, and a stand where Japanese red pine Pinus densiflora seedlings were planted after the fire were used for the survey. Habitat structure was dramatically changed by postfire silvicultural practices. Number of stand trees, shrubs, seedlings, snags, and vegetation coverage were significantly different among study stands. We made 1,421 detections of 46 bird species during 23 separate line transect surveys per stand between February 2007 and December 2008. The mean number of observed bird species and individuals, bird species diversity index (H′), and Simpson’s diversity index (D _s) were highest in the unburned stand and lowest in the pine seedling stand. There were more species and individuals of forest-dwelling birds in the unburned stand than both burned stands. Canopy and cavity nesters, foliage searchers, bark gleaners, and timber drillers were significantly higher in the unburned stand. In the pine seedling stand, densities of birds that prefer open field and shrub cover were higher. Stand structure was simplified in the pine seedling stand by postfire practices. Because of differences in habitat structure and bird communities, postfire practices in the burned stand should be re-evaluated. Also, management strategies for pine forest after forest fires are needed based on results of long-term experiments.     

Does habitat structure matter? Spatially explicit population modelling of an Iberian gypsum endemic

Habitat heterogeneity may influence plant demography because conditions for survival, growth, and reproduction vary within a species’ range. We assessed the role of microhabitat spatial structure on the demography of Helianthemum squamatum, a shrubby gypsum specialist endemic to the Iberian Peninsula. We evaluated the demographic effect of microhabitat spatial variation using an approach that combined cellular automata with matrix population models, and included environmental and demographic stochasticty. We collected data on seed bank (2003–2005), seedling emergence (2003–2006), and adult survivorship (2004–2007) for H. squamatum in two independent blocks with different grazing intensity in Belinchón (Cuenca, Spain). We built spatial scenarios for each block based on field data of cover and spatial pattern of four microhabitats: lichenic crust, litter, H. squamatum, and shrub. Seedling survivorship was affected by year, block, and microhabitat, with individuals emerging under conspecifics having the highest survival rate and on litter the lowest in both blocks, whereas the effect of crust and other shrubs differed across blocks. Our models indicated population increase in the block with low grazing, but population decline in the block with intense grazing. We hypothesize that higher pressure of livestock grazing and trampling leads to a shift in relative microhabitat suitability for crust and shrub. This potential effect of grazing on spatial demographic variation opens interesting questions for future research. We emphasize the importance of considering microhabitat spatial structure when evaluating management and conservation strategies. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Complete genotyping in conservation genetics, a case study of a critically endangered shrub, Stachyurus macrocarpus var. prunifolius (Stachyuraceae) in the Ogasawara Islands, Japan

More than 3,000 species are listed as critically endangered worldwide, and various conservation measures such as habitat restoration, assisted reproduction and establishment of ex situ populations would be required to prevent their extinction. We determined the genotype of all 15 known wild clumps using nuclear microsatellite markers for Stachyurus macrocarpus var. prunifolius, a critically endangered shrub endemic to the Ogasawara (Bonin) Islands of Japan. In addition, the seedlings propagated from seeds taken from one wild clumps were genotyped. The results of complete genotyping showed that both wild and nursery populations had population-specific alleles. Two alleles were detected only in the nursery population, indicating the existence of undiscovered mature individuals in the wild. Four alleles were found only in the wild and were detected in two geographically isolated clumps, and this finding may propose that re-introduction and transplantation between different sites requires sensitive handling in terms of the conservation of evolutionary significant units. These results show that complete genotyping can provide essential genetic and ecological information for effective management of endangered species.     

Demographic differences between two sympatric lilies (<Emphasis Type="Italic">Calochortus</Emphasis>) with contrasting distributions,as revealed by matrix analysis

Related species of similar morphology can differ greatly in distribution and abundance. Elucidating reasons for such differences can contribute to an understanding of intrinsic limiting factors and the causes of rarity. We studied sympatric populations of two terrestrial lilies with contrasting distributions: Calochortus lyallii, which is geographically restricted but locally abundant, and C. macrocarpus, which is widespread but locally sparse. Marked plants of each species were monitored for 5 years in British Columbia, Canada. Matrix projection models were used to estimate annual and stochastic population growth rates (λ and λ_s) and to compare demographic traits. Annual λ-values ranged from 0.89 to 1.04 in C. lyallii and from 0.89 to 1.01 in C. macrocarpus. Stochastic projections yielded a long-term growth rate near 1 for C. lyallii, but indicated a decline for C. macrocarpus. Elasticity analysis indicated that over the 5-year period of the study, survival of flowering plants made a larger proportional contribution to λ in C. lyallii than in C. macrocarpus. LTRE analysis showed that temporal variation in λ was driven primarily by the dynamics of flowering individuals in C. lyallii, and by the dynamics of vegetative individuals in C. macrocarpus. Similarly, higher flowering rates in C. lyallii and greater vegetative stasis in C. macrocarpus made the largest contribution to the difference in λ between species. Thus, local persistence in these two morphologically similar species appears to be achieved via different demographic pathways. Our analyses show that extrapolations about demographic processes and population dynamics based on taxonomic relatedness, morphological similarity or habitat overlap may often not be justified. Electronic Supplementary Material The online version of this article contains supplementary material, which is available to authorised users.     

Home‐range size and habitat use of European Nightjars Caprimulgus europaeus nesting in a complex plantation‐forest landscape

In Europe, the consequences of commercial plantation management for birds of conservation concern are poorly understood. The European Nightjar Caprimulgus europaeus is a species of conservation concern across Europe due to population depletion through habitat loss. Pine plantation‐forest is now a key Nightjar nesting habitat, particularly in northwestern Europe, and increased understanding of foraging habitat selection is required. We radiotracked 31 Nightjars in an extensive (185‐km²) complex conifer plantation landscape in 2009 and 2010. Home‐range 95% kernels for females, paired males and unpaired males were an order of magnitude larger than song territories of paired males, emphasizing the importance of habitats beyond the song territory. Nightjars travelled a mean maximum distance of 747 m from the territory centre each night. Home‐range placement relative to landscape composition was examined by compositional analysis. Pre‐closure canopy forest (aged 5–10 years) was selected at all scales (MCP, 95% and 50% kernels), with newly planted forest (aged 0–4 years) also selected within 50% kernels. For telemetry fixes relative to habitat composition within 2 km of their territory centre, individuals again selected pre‐closure and newly planted forest, and also grazed grass heath. Open ungrazed habitat was not selected, with implications for open habitat planning for biodiversity conservation within public‐owned forests. Despite the Nightjars’ selection for younger growth, moth biomass was greater in older forest stands, suggesting that foraging site selection reflects ease of prey capture rather than prey abundance. Within large plantation‐forest landscapes, a variety of growth stages is important for this species and our results suggest that grazing of open habitats within and adjacent to forest will additionally benefit the European Nightjar.     

Range‐wide genetic analysis reveals limited structure and suggests asexual patterns in the rare forb Senecio macrocarpus

Genetic diversity and recombination underlie the long‐term persistence and evolution of species and are strongly influenced by population size, breeding system and plant longevity. Here, we study genetic structure in the rare Senecio macrocarpus in southeastern Australia to guide current conservation practices. Thirteen neutral microsatellite markers and two chloroplast regions were used to survey the 20 known S. macrocarpus populations and one sympatric S. squarrosus population, a morphologically similar species. All markers showed severe excess or deficit of heterozygotes and linkage disequilibrium was significant. Microsatellite markers revealed 100 multi‐locus genotypes (MLGs) from 523 S. macrocarpus individuals and a further 4 MLGs from 27 S. squarrosus individuals. MLGs varied in frequency and distribution. At the extremes, one MLG was found 108 times across the sampling region and 66 MLGs were found once. The MLGs of all 38 seedlings genotyped were identical to their seed parents implying an asexual origin. Chloroplast regions showed little variation within S. macrocarpus but differed from S. squarrosus. Chromosome counts for S. macrocarpus revealed the same ploidy level as S. squarrosus (2n = 6x = 60) and pollen–ovule ratios were typical of erechthitoid Senecio species showing self‐compatibility. Results suggest that establishment of small populations occur primarily from one extensive source population with indications that both apomixis and selfing may be contributing to its reproduction cycle. We suggest that this species may contribute to future evolutionary processes despite limited genotypic variation and restricted distribution. Its conservation will safeguard evolutionary processes that might occur through occasional outcrossing and hybridization events between sympatric species. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 115 , 256–269.     

Regeneration pattern of primary forest species across forest-field gradients in the subtropical Mountains of Southwestern China

Evergreen broad-leaved forest is now gradually degraded and fragmented, and there is an increase in the amount of habitat edges as a result of long-term human activity. However, the role of edges in the regeneration of primary forest species is poorly understood. After 20 years of the edge creation, we analyzed primary forest species distribution and abundance, and changes in floristic composition, vegetation structure across forest-field gradients in Ailao Mountain, SW China. Our results revealed that there was a higher abundance and richness of primary species, late secondary species and thorny lianas at the distances 0–50 m than at the distances more than 50 m from the edge into the forest exterior. At the distances >50 m, no individuals of dominant canopy trees Lithocarpus xylocarpus, Castanopsis wattii, and L. jingdongensis were found, whereas the abundance of early pioneer shrub species and herbaceous cover was significantly greater. The richness of primary species showed a decrease with increasing distances from the forest edge to the exterior, particularly of medium-seeded primary species showing a drastic decrease. Moreover, no large-seeded primary species occurred at the distances >60 m. This study indicates that the forest edge as a buffer zone may be in favor of primary species regeneration. A dense shrub and herb layer, and seed dispersal may be the major factors limiting the forest regeneration farther from the forest edge. Therefore, to facilitate forest recovery processes, management should give priority to the protection of buffer zones of this forest edge.     

Effect of Resting Patterns of Tamarins (<Emphasis Type="BoldItalic">Saguinus fuscicollis</Emphasis> and <Emphasis Type="BoldItalic">Saguinus mystax</Emphasis>) on the Spatial Distribution of Seeds and Seedling Recruitment

The spatial distributions of dispersed seeds have important evolutionary consequences for plants. Repeated defecations in sites frequently used by seed dispersers can result in high seed concentrations. We observed the resting behavior of a mixed-species group of tamarins in Peru and recorded the occurrence of seed dispersal (over 8 mo) and seed fate (over 11–22 mo) to determine whether the location and use of resting sites influenced the spatial distribution of dispersed seeds and seedlings. The tamarins rested mostly on trees (Saguinus fuscicollis: 60.6%, S. mystax: 89.2%) and dead trunks (S. fuscicollis: 24.4%) and used 61% of their resting sites repeatedly. During both the dry and wet seasons, tamarins dispersed significantly more seeds within resting areas (0.00662 and 0.00424 seeds/m², respectively) than outside them (0.00141 and 0.00181 seeds/m²). Seed survival and seedling recruitment did not differ significantly between resting and other areas, resulting in a higher seedling concentration around the resting sites. Seed density did not increase with the duration or the frequency of use of the resting sites but did increase when we pooled the seasonal resting sites together in 50 m × 50 m quadrats, ultimately causing a clumped distribution of dispersed seeds. The use of resting sites in secondary forest, particularly during the dry season, allows the creation of seedling recruitment centers for species coming from the primary forest. Our findings show that tamarin resting behavior affects the spatial distribution of dispersed seeds and seedlings, and their resting sites play an important role in plant diversity maintenance and facilitate forest regeneration in degraded areas.     

Density and Spatial Distribution of Buffy-tufted-ear Marmosets (<Emphasis Type="Italic">Callithrix aurita</Emphasis>) in a Continuous Atlantic Forest

The continued degradation of forest habitats and isolation of fragmented populations means that the conservation of endemic marmosets in the Brazilian Atlantic forest depends on human interventions including legal protection. Population monitoring is required to ensure effective management and appropriate allocation of conservation resources; however, deriving estimates of population metrics such as density within heterogeneous environments is challenging. We aimed to quantify the population density and spatial distribution of buffy-tufted-ear marmosets (Callithrix aurita) in the northern region of Serra-do-Mar State Park. We incorporated habitat suitability as quantified by a niche modeling algorithm (MAXENT) to refine density estimates obtained via distance methods. We used 6 environmental predictors to model the distribution of Callithrix aurita and used the resulting MAXENT niche model to identify environmental conditions that represent suitable habitat for this species. We used 877.7 km of line transect surveys and distance methods to derive estimates of 2.19 groups or 7.55 individuals/km² from direct observations (n = 40), providing an overall population estimate of 1892 (95% CI = 1155–3068) individuals in 250.7 km² of Atlantic forest. Our refined density estimate, obtained by combining distance methods and a niche model, yielded a result of 1386 individuals. Suitable habitat was not uniformly distributed across the study area and was most strongly associated with altitude and the type of vegetation cover. We provide a review of previous surveys and find this is the largest known population of Callithrix aurita. Our refinement of density estimates provides a simple and informative addition to the primatologist’s toolbox.     

Influence of cattle grazing on the density of oak seedlings and saplings in a Tabor oak forest in Israel

The effects of cattle grazing on the density of seedlings and saplings in a Tabor oak forest (Quercus ithaburensis subsp. ithaburensis) are investigated. The Tabor oak forest studied is located in a Nature Reserve in the Mediterranean region of Israel. Cattle graze at a stocking density of 0.71 head/ha for 6 months a year. The cattle grazing in the Nature Reserve is a beneficial management measure because it enhances plant species richness and reduces shrub encroachment.The impact of grazing on the densities of seedlings and young saplings was quantified in 46 large sampling plots (333 m² each) distributed over two experimental sites; the first being used as a rangeland for decades while the second is a forest patch totally free from grazing. The density and the height of Tabor oak individuals in each sampling plot were recorded. Four height categories were distinguished with a special focus on young seedlings (<0.15 m), established seedlings and young saplings (0.15 m–1 m).The density of seedlings and young sapling in the grazed Tabor oak forest were, respectively, 61% to 67% lower than in the ungrazed treatment. Implications on the continuity of the entire Tabor oak forest ecosystem are discussed. Three management measures that enable to prevent a decrease in young oak densities are proposed – reduction of stocking rate, deferment of the commencement of grazing, and fencing young seedlings.     

Fine-scale genetic structure of a long-lived reptile reflects recent habitat modification

Anthropogenic habitat fragmentation — ubiquitous in modern ecosystems — has strong impacts on gene flow and genetic population structure. Reptiles may be particularly susceptible to the effects of fragmentation because of their extreme sensitivity to environmental conditions and limited dispersal. We investigate fine-scale spatial genetic structure, individual relatedness, and sex-biased dispersal in a large population of a long-lived reptile (tuatara, Sphenodon punctatus) on a recently fragmented island. We genotyped individuals from remnant forest, regenerating forest, and grassland pasture sites at seven microsatellite loci and found significant genetic structuring (R_ST = 0.012) across small distances (< 500 m). Isolation by distance was not evident, but rather, genetic distance was weakly correlated with habitat similarity. Only individuals in forest fragments were correctly assignable to their site of origin, and individual pairwise relatedness in one fragment was significantly higher than expected. We did not detect sex-biased dispersal, but natural dispersal patterns may be confounded by fragmentation. Assignment tests showed that reforestation appears to have provided refuges for tuatara from disturbed areas. Our results suggest that fine-scale genetic structuring is driven by recent habitat modification and compounded by the sedentary lifestyle of these long-lived reptiles. Extreme longevity, large population size, simple social structure and random dispersal are not strong enough to counteract the genetic structure caused by a sedentary lifestyle. We suspect that fine-scale spatial genetic structuring could occur in any sedentary species with limited dispersal, making them more susceptible to the effects of fragmentation.     

Seedling and Sprout Response to Slash-and-Burn Agriculture in a Tropical Deciduous Forest1

Survival and growth of seedlings and sprouts were assessed in three plots for 16 mo following the slashing and burning of a tropical deciduous forest in Jalisco, Mexico. We encountered a total of 47 species: 21 seedling species and 35 sprout species. Calliandra formosa and Piptadenia flava were the most common seedling species; Bursera arborea, Cordia alliodora, and Piptadenia constricta were the most common sprouts. Colubrina triflora, Diphysa occidentalis, and Cnidoscolus spinosus had limited sprouting ability. Twenty-six species were represented by one seedling or one sprout. Thirty-eight percent of the seedlings were tree species, 59 percent were shrub species, and 2 percent were vines species. In contrast, 86 percent of the sprouts were from trees and 13 percent from shrubs. One year after the initial measurements, 29 percent of the seedlings and 13 percent of the sprouts were dead. Each of the seedling means (number of stems/individual, height and diameter of the tallest stem, and elliptical crown area) was significantly smaller (P < 0.05) than that of sprouts at all three measurement periods, but relative growth rates were similar. Total canopy area of seedlings had a larger relative increase than did the canopy area of sprouts. The presence of seedlings increased species diversity compared to calculated diversity excluding seedlings. Timing of fruit dispersal in relation to the date of burning and the high number of Leguminosae species in the forest appeared to favor seedling establishment for some species.     

Does post-fire abiotic habitat filtering create divergent plant communities in black spruce forests of eastern Canada?

We investigated the role of post-fire residual organic matter (ROM) thickness as a driver of community assembly in eastern Newfoundland. We hypothesized that if post-fire community assembly is predominantly controlled by ROM thickness (an abiotic habitat filter), then post-fire species composition and functional traits should correspond to the depth and distribution of ROM. However, if species interactions (biotic filter) are the primary constraints on community assembly, then post-fire species composition and their functional traits should be independent of the depth and distribution of ROM. We tested these predictions in three relatively mature plant communities, Kalmia angustifolia heath, black spruce (Picea mariana)-Kalmia shrub savannah and black spruce forest. Through pre-fire stand reconstruction, we found evidence that the three communities originated from black spruce forest. ROM thickness in heath was almost twice that of shrub savannah and six times more than forest, suggesting a gradient in fire severity. Distribution of ROM corresponded to patterns in vegetation dominance, where thick ROM (>2 cm) filtered out black spruce in favour of Kalmia. ROM thickness was a strong predictor of vegetation composition and function between heath and forest, but this was not found between the shrub savannah and forest. We attribute this to species interactions and allelopathy, which may have become important when ROM thickness was suitable for both seed (black spruce) and vegetative (Kalmia) regenerating species. Thus, priority effects or “who came first” may have lead to shrub savannah formation when ROM thickness was ~2 cm. We conclude that abiotic habitat filtering of thick ROM (>2 cm) on (primarily) species’ regeneration traits was the primary driver of community divergence from forest to heath and shrub savannah.     

Importance of habitat patch size for occupancy and density of aspen-associated saproxylic beetles

In Fennoscandian boreal forests, aspen (Populus tremula) is one of the most important tree species for biodiversity. In this study we explore how occupancy and density of beetles associated with dead aspen are related to habitat patch size and connectedness in a 45,000 ha boreal managed forest landscape in central Sweden. Patch size was estimated as amount of breeding substrate and connectedness as crown cover of living aspen in the surrounding landscape. The beetles were sampled by sieving of bark or by inspection of species-characteristic galleries in 56 patches with dead aspen. Six of nine aspen-associated species (Xylotrechus rusticus, Ptilinus fuscus, Mycetophagus fulvicollis, Cyphaea curtula, Homalota plana and Endomychus coccineus) showed a positive significant relationship between habitat patch size and occupancy. For all these species, except C. curtula, there was also a significant positive relationship between patch size and density. Connectedness was not retained as a significant variable in the analyses. Species not defined as aspen-associated constituted a significantly larger proportion of the total density of individuals of saproxylic beetles in smaller habitat patches than in larger patches. Richness of aspen-associated species was positively related to habitat patch size. Efforts in the managed forest should be directed towards preserving and creating larger patches of living and dead aspen trees and increasing the amount of aspen at the landscape level.     

Consequences of habitat disturbance on seed fate of a Brazilian tropical dry forest tree Cavanillesia arborea (Malvaceae)

We compared seed fate (survival, mortality by rodent predators, desiccation and other causes) of the tree Cavanillesia arborea (Malvaceae) in preserved old‐growth tropical dry forests and in nearby abandoned pasturelands in Brazil. For this purpose, we performed an experiment where 15 seeds were placed in the surroundings of 15 parental individuals in each habitat. These 450 seeds were monitored over four months. At the end of the experiment, seed predation by rodents was higher in forest (56.5%) than in pasture (8.9%) areas, but seed desiccation showed the opposite pattern (8.9% vs. 80.4%). Mortality by desiccation was also faster in pasture than in forest areas, probably reducing their attractiveness to predators in these areas. None of the seeds placed in the pasture survived, whereas 26.2% of seeds became seedlings in forest areas. The absence of seedling recruitment of Cavanillesia arborea in pastures is likely a consequence of their incapacity to tolerate the harsh abiotic conditions in this habitat. Thus, forest conversion imposes a strong limitation to the long‐term population viability of this species. However, restoration and natural regeneration of abandoned pastures can recreate the forest structure and microclimatic conditions favourable to seed germination and seedling establishment. Remnant individuals of Cavanillesia arborea in agricultural landscapes may have a negligible contribution to current recruitment, but they can attract potential dispersers of pioneer species, with positive feedbacks to future recruitment during secondary succession.     

Habitat fragmentation influences genetic diversity and differentiation: Fine‐scale population structure of Cercis canadensis (eastern redbud)

Forest fragmentation may negatively affect plants through reduced genetic diversity and increased population structure due to habitat isolation, decreased population size, and disturbance of pollen‐seed dispersal mechanisms. However, in the case of tree species, effective pollen‐seed dispersal, mating system, and ecological dynamics may help the species overcome the negative effect of forest fragmentation. A fine‐scale population genetics study can shed light on the postfragmentation genetic diversity and structure of a species. Here, we present the genetic diversity and population structure of Cercis canadensis L. (eastern redbud) wild populations on a fine scale within fragmented areas centered around the borders of Georgia–Tennessee, USA. We hypothesized high genetic diversity among the collections of C. canadensis distributed across smaller geographical ranges. Fifteen microsatellite loci were used to genotype 172 individuals from 18 unmanaged and naturally occurring collection sites. Our results indicated presence of population structure, overall high genetic diversity (H_E = 0.63, H_O = 0.34), and moderate genetic differentiation (F_ST = 0.14) among the collection sites. Two major genetic clusters within the smaller geographical distribution were revealed by STRUCTURE. Our data suggest that native C. canadensis populations in the fragmented area around the Georgia–Tennessee border were able to maintain high levels of genetic diversity, despite the presence of considerable spatial genetic structure. As habitat isolation may negatively affect gene flow of outcrossing species across time, consequences of habitat fragmentation should be regularly monitored for this and other forest species. This study also has important implications for habitat management efforts and future breeding programs.     

Fecundity,fruiting pattern,and seed dispersal in Piper amalago (Piperaceae), a bat-dispersed tropical shrub

Summary This paper describes the nightly and seasonal production of ripe fruit by Piper amalago (Piperaceae), a patchily distributed, bat-dispersed forest shrub, at Parque Nacional Santa Rosa, Costa Rica. Phenological observations over several years indicate that individuals produce a low (usually 1–3) and variable number of ripe fruit each night for 3–4 wks in the early wet season (June and July). Observations of the disappearance rates of marked fruits and fruit manipulation experiments indicate that fruit removal probabilities are high (often nearly 1.0) and independent of nightly and seasonal ripe fruit crop size. Data from previous feeding and foraging studies of the bat Carollia perspicillata (Phyllostomidae) are used to estimate the mobility of P. amalago's seeds. Most seeds (>90%) are deposited 50 m from parent plants under night feeding roosts. Relatively few seeds move >300 m, and movements this long are more likely to occur early and late in the fruiting season when bats change feeding sites more frequently. Seed experiments indicate that P. amalago seedling establishment probabilities are higher in light gaps than under forest canopy. The dispersal quality (sensu McKey 1975) of P. amalago's chiropteran seed dispersers is directly proportional to the number of seeds they excrete in actual or incipient light gaps.