Large Forest Patches Promote Breeding Success of a Terrestrial Mammal in Urban Landscapes

Despite a marked increase in the focus toward biodiversity conservation in fragmented landscapes, studies that confirm species breeding success are scarce and limited. In this paper, we asked whether local (area of forest patches) and landscape (amount of suitable habitat surrounding of focal patches) factors affect the breeding success of raccoon dogs (Nyctereutes procyonoides) in Tokyo, Central Japan. The breeding success of raccoon dogs is easy to judge as adults travel with pups during the breeding season. We selected 21 forest patches (3.3–797.8 ha) as study sites. In each forest patch, we used infra-red-triggered cameras for a total of 60 camera days per site. We inspected each photo to determine whether it was of an adult or a pup. Although we found adult raccoon dogs in all 21 forest patches, pups were found only in 13 patches. To estimate probability of occurrence and detection for raccoon in 21 forest fragments, we used single season site occupancy models in PRESENCE program. Model selection based on AIC and model averaging showed that the occupancy probability of pups was positively affected by patch area. This result suggests that large forests improve breeding success of raccoon dogs. A major reason for the low habitat value of small, isolated patches may be the low availability of food sources and the high risk of being killed on the roads in such areas. Understanding the effects of local and landscape parameters on species breeding success may help us to devise and implement effective long-term conservation and management plans.     

Fine-Scale Habitat Heterogeneity Influences Occupancy in Terrestrial Mammals in a Temperate Region of Australia

Vegetation heterogeneity is an inherent feature of most ecosystems, characterises the structure of habitat, and is considered an important driver of species distribution patterns. However, quantifying fine-scale heterogeneity of vegetation cover can be time consuming, and therefore it is seldom measured. Here, we determine if heterogeneity is worthwhile measuring, in addition to the amount of cover, when examining species distribution patterns. Further, we investigated the effect of the surrounding landscape heterogeneity on species occupancy. We tested the effect of cover and heterogeneity of trees and shrubs, and the context of the surrounding landscape (number of habitats and distance to an ecotone) on site occupancy of three mammal species (the black wallaby [Wallabia bicolor], the long-nosed bandicoot [Perameles nasuta], and the bush rat [Rattus fuscipes]) within a naturally heterogeneous landscape in a temperate region of Australia. We found that fine-scale heterogeneity of vegetation attributes is an important driver of mammal occurrence of two of these species. Further, we found that, although all three species responded positively to vegetation heterogeneity, different mammals vary in their response to different types of vegetation heterogeneity measurement. For example, the black wallaby responded to the proximity of an ecotone, and the bush rat and the long-nosed bandicoot responded to fine-scale heterogeneity of small tree cover, whereas none of the mammals responded to broad scale heterogeneity (i.e., the number of habitat types). Our results highlight the influence of methodological decisions, such as how heterogeneity vegetation is measured, in quantifying species responses to habitat structures. The findings confirm the importance of choosing meaningful heterogeneity measures when modelling the factors influencing occupancy of the species of interest.     

Mammal Abundances and Seed Traits Control the Seed Dispersal and Predation Roles of Terrestrial Mammals in a Costa Rican Forest

In Neotropical forests, mammals act as seed dispersers and predators. To prevent seed predation and promote dispersal, seeds exhibit physical or chemical defenses. Collared peccaries (Pecari tajacu) cannot eat some hard seeds, but can digest chemically defended seeds. Central American agoutis (Dasyprocta punctata) gnaw through hard‐walled seeds, but cannot consume chemically defended seeds. The objectives of this study were to determine relative peccary and agouti abundances within a lowland forest in Costa Rica and to assess how these two mammals affect the survival of large seeds that have no defenses (Iriartea deltoidea, Socratea exorrhiza), physical defenses (Astrocaryum alatum, Dipteryx panamensis), or chemical defenses (Mucuna holtonii) against seed predators. Mammal abundances were determined over 3 yrs from open‐access motion‐detecting camera trap photos. Using semi‐permeable mammal exclosures and thread‐marked seeds, predation and dispersal by mammals for each seed species were quantified. Abundances of peccaries were up to six times higher than those of agoutis over 3 yrs, but neither peccary nor agouti abundances differed across years. Seeds of A. alatum were predominantly dispersed by peccaries, which did not eat A. alatum seeds, whereas non‐defended and chemically defended seeds suffered high levels of predation, mostly by peccaries. Agoutis did not eat M. holtonii seeds. Peccaries and agoutis did not differ in the distances they dispersed seeds. This study shows that seed fates are contingent upon many factors such as seed defenses, frugivore–granivore abundances, and seed‐handling capabilities. Mammal–seed interactions are complex; the outcomes of these interactions depend on the inherent characteristics of seeds and their potential dispersers.     

Phylogenetic and Morphologic Analyses of a Coastal Fish Reveals a Marine Biogeographic Break of Terrestrial Origin in the Southern Caribbean

Background

Marine allopatric speciation involves interplay between intrinsic organismal properties and extrinsic factors. However, the relative contribution of each depends on the taxon under study and its geographic context. Utilizing sea catfishes in the Cathorops mapale species group, this study tests the hypothesis that both reproductive strategies conferring limited dispersal opportunities and an apparent geomorphologic barrier in the Southern Caribbean have promoted speciation in this group from a little studied area of the world.

Methodology/Principal Findings

Mitochondrial gene sequences were obtained from representatives of the Cathorops mapale species group across its distributional range from Colombia to Venezuela. Morphometric and meristic analyses were also done to assess morphologic variation. Along a ∼2000 km transect, two major lineages, Cathorops sp. and C. mapale, were identified by levels of genetic differentiation, phylogenetic reconstructions, and morphological analyses. The lineages are separated by ∼150 km at the Santa Marta Massif (SMM) in Colombia. The northward displacement of the SMM into the Caribbean in the early Pleistocene altered the geomorphology of the continental margin, ultimately disrupting the natural habitat of C. mapale. The estimated ∼0.86 my divergence of the lineages from a common ancestor coincides with the timing of the SMM displacement at ∼0.78 my.

Main Conclusions/Significance

Results presented here support the hypothesis that organismal properties as well as extrinsic factors lead to diversification of the Cathorops mapale group along the northern coast of South America. While a lack of pelagic larval stages and ecological specialization are forces impacting this process, the identification of the SMM as contributing to allopatric speciation in marine organisms adds to the list of recognized barriers in the Caribbean. Comparative examination of additional Southern Caribbean taxa, particularly those with varying life history traits and dispersal capabilities, will determine the extent by which the SMM has influenced marine phylogeography in the region.     

桂西地区南亚热带落叶栎林群落组成及物种多样性研究北大核心CSCD

落叶栎林是桂西地区南亚热带的典型次生林,也是该区域落叶阔叶林的重要群系组。该研究采用典型样方法对桂西地区落叶栎林群落进行调查,分析了该区域落叶栎林群落的物种组成、区系成分、物种多样性特征及其与地形因子的关系,为桂西地区南亚热带植物多样性保护与恢复提供依据。结果显示:(1)研究区落叶栎林群落维管束植物共计269种,隶属80科178属。(2)种子植物区系以热带成分为主,同时表现出一定程度的温带过渡性质。(3)聚类分析表明,调查的落叶栎林群落可分为云南波罗栎林、栓皮栎林、白栎林、麻栎林4种林分类型,其中以白栎林群落的物种多样性最高,且灌木层的物种多样性显著高于乔木层和草本层。(4)RDA分析显示,落叶栎林群落不同层次物种多样性的差异受地形因子的影响,多样性指标与经度、纬度、海拔之间具有明显的相关性(P<0.05),其中乔木层物种多样性主要与经度、纬度呈显著的相关性,灌木层物种多样性与纬度、海拔相关,草本层物种多样性与经度、纬度、海拔之间均有相关性。     

Soil Characteristics and Vegetation Structure in a Heavily Deteriorated Mangrove Forest in the Caribbean Coast of Colombia

Mass mortality and biomass of mangrove trees are related to soil factors in the Caribbean Coast of Colombia. Soil properties measured were particle size distribution, bulk density, organic matter, total nitrogen, total phosphorus, pH, redox potential, salinity, and extractable nitrogen (NO₂, NO₃, NH₄) and phosphorus (PO₄). Sampling was performed at three locations along two 50 m transects at each site. Soil nutrient concentrations of either exchangeable nitrogen or phosphorus were comparable to other reported values. Redox potentials (E_h) were variable probably due to microtopographic conditions and to the amount of water and organic matter present in the soil. Hydrogen potentials (pH) are within the range reported as normal for mangrove soils. Locations with highest biomass had an average soil salinity of 35 with a range of 20 to 53. Sites with dead or dwarfed vegetation had an average soil salinity of 74 and minimum and maximum values observed were 52 and 100 respectively. Statistical analysis exhibited temporal and spatial differences in soil salinity and suggest that this parameter is most correlated to the development and distribution of mangrove vegetation in the area indicating that basal area and biomass volume are inversely correlated with soil salinity.     

Patterns and Trends of Forest Loss in the Colombian Guyana

Spatial patterns of tropical deforestation and fragmentation are conditional upon human settlement characteristics. We analyze four different human occupation models (indigenous, colonist frontier, transition and established settlement) in the Colombian Guyana Shield at three different times: 1985, 1992 and 2002, and compared them for: (1) deforestation rates; (2) the amount of forest as classified according to a fragmentation pattern (interior forest, edge forest, perforated forest and forest patch); (3) various fragmentation metrics using repeated measures analysis of variance; and (4) potential future deforestation trends though the implementation of a spatially explicit simulation model. The indigenous and colonist frontier occupation models had low rates of deforestation (0.04%/yr), while the well‐established settlement occupation model had the highest rate (3.68%/yr). Our results indicate that the four occupation models generate three deforestation patterns: diffuse, which can be subdivided into two subpatterns (indigenous and colonist), geometric (transition) and patchy (established settlement). The area with the established settlement model was highly fragmented, while in the transition occupation area, forest loss was gradual and linked to economic activities associated with the expansion of the agricultural frontier. The simulation of future trends revealed that indigenous and colonist areas had a constant, albeit small, loss of forest covers. The other models had a deforestation probability of 0.8 or more. Overall, our results highlight the need for new and urgent policies for reducing forest conversion that consider intraregional variability in human occupation linked to differences in land‐use patterns. Abstract in Spanish is available in the online version of this article.     

Comparative Ecophysiology and Anatomy of Terrestrial and Epiphytic Anthurium bredemeyeri Schott in a Tropical Andean Cloud Forest

Water relations and anatomy of a casual epiphyte were studiedat La Carbonera, a tropical cloud forest. Anthurium bredemeyerigrowing as an epiphyte and in its terrestrial form were studiedto find differences due to their different habits. Both formsmaintained relatively high leaf conductances (0·12 to0·15 mol m² s¹) when leaf ater potential was relativelyhigh (above – 0·5 MPa). A lowering of the leafwater potential (below – 0·5 MPa) during the dryseason, significantly affected leaf conductances in both terrestrialand epiphytic forms, the latter one to a greater degree. Interms of anatomy, a reduction in stomatal density was observedin the epiphyte, although no other differences were observed.The results show how the epiphyte was affected to a greaterdegree by a decrease in water availability during the dry seasoncompared to the terrestrial form. Key words: Anthurium bredemeyeri, epiphyte, water relations, anatomy     

Trophic Niche Differentiation and Microhabitat Utilization in a Species‐rich Montane Forest Small Mammal Community of Eastern Madagascar

Unraveling the mechanisms facilitating species coexistence in communities is a central theme in ecology. Species‐rich tropical mammal communities provide excellent settings to explore such mechanisms as they often harbor numerous congeneric species with close phylogenetic relationships. Explicit tests for the mechanisms that allow syntopic occurrence in these assemblages, however, is often hampered because of the difficulty in obtaining detailed ecological data on the organisms making up the community. Using stable nitrogen and carbon ratios of hair samples, we examine whether trophic niche differentiation and microhabitat segregation explain the coexistence of 21 small mammal species at a montane humid forest site in eastern Madagascar. Overall, the community was trophically diverse and covered wide isotopic space. This diversity was based on: (1) a multi‐layered trophic community structure with mainly frugivorous‐granivorous rodents (subfamily Nesomyinae) as primary consumers and insectivorous tenrecs (family Tenrecidae) as secondary and tertiary consumers; (2) trophic segregation of rodents and tenrecs with the latter occupying different microhabitats; and (3) a dense and regular packing of species in the community. The 12 locally occurring Microgale shrew tenrecs (subfamily Oryzorictinae) showed high trophic redundancy, but were maximally spaced from each other within the trophic space covered by the genus. Results of stable isotope analysis suggest that in combination the differentiation of microhabitats and trophic niches explain the coexistence of small mammals in this community. Congeneric species appeared to be under more intense competition compared with non‐congeneric species and their coexistence can only partly be explained by trophic and microhabitat niche segregation.     

Labile Phosphorus in Soils of Forest Fallows and Primary Forest in the Bragantina Region, Brazil

We used the Hedley sequential extraction procedure to measure nine different organic inorganic soil phosphorus fractions in forest soil of the Bragantina region of Para, Brazil. We compared the labile fractions (resin‐extractable P + HCO3‐extractable inorganic and organic P) in Oxisols from three secondary forests (10, 20, and 40 years old) and a primary forest. These stands were located in an area that has supported shifting agriculture for approximately a century. After agricultural use, total P and labile P in soils of young secondary forests are diminished compared to the amounts presents in the primary forest soil. Within each stand, organic carbon content was a good predictor of labile organic and inorganic P, consistent with the large body of research indicating that mineralization of organic matter is important to plant nutrition in tropical ecosystems. During the reorganization of P pools during forest development, the pool of labile organic P (HCO3‐extractable) diminishes more than the other labile fractions, suggesting that it is directly or indirectly an important source of P for the regrowing forest vegetation. Across the four age classes of forest, the soil reservoir of labile P was equal to or greater than the total amount of P in the vegetation. If labile P measured by this method adequately represents P available to plants in the short term (as suggested by the current consensus), we would conclude that plant‐available P is reasonable abundant, and that the effects of agriculture on available P pools are detectable but not sufficient to compromise forest regrowth in this area.     

High Conservation Value of Forest Fragments for Plant and Frugivore Communities in a Fragmented Forest Landscape in South Africa

Fragmentation is a major threat factor for plant–frugivore communities in tropical and subtropical forests. Resulting changes in the distribution of traits within these communities, e.g., a loss in large‐bodied frugivores, may lead to strong changes in plant–frugivore interactions in fragmented forests. Yet, we still lack a thorough understanding of the interplay between forest fragmentation, the trait‐composition of communities and resulting plant–frugivore interactions on a community‐scale. In a fragmented South African landscape comprising different forest categories—i.e., continuous natural forest, forest fragments surrounded by natural grassland, and forest fragments surrounded by sugarcane—we investigated the relationship between communities of fruiting plants and their frugivore visitors in response to forest fragmentation, as well as the interactive effects of forest fragmentation and fruit size of the plants on the number of frugivore visitors and their body size. Neither the fruit size of plant nor the body mass of frugivore communities differed between natural forest sites and forest fragments. Moreover, in‐depth analyses of frugivore assemblages visiting plant species revealed no effect of forest category on the number of frugivore visits or their mean body mass. The number of visits and body mass of frugivores were merely determined by the crop and fruit size of the focal plant species. Overall, our results suggest that frugivory of plant species with differently sized fruits was not reduced in forest fragments. Thus, fragments with high fruit availability may be key elements maintaining the functional connectivity of a heterogeneous forest landscape.     

Proposed association between airborne pollen and pediatric asthma emergency room visits in the Caribbean Island of Trinidad and Tobago West Indies

There are a number of possible links between airborne pollen and respiratory disease that remain underappreciated by both the scientific community and health care providers within the Latin American and Caribbean region. A few regional studies have assimilated some preliminary information on this association, and most recently research on interactions between airborne pollen and pediatric asthma on the Caribbean island of Trinidad has shown critical areas that require further investigation. Pollen samples were collected over a 2-year period using a Burkard 7 Day Recording Volumetric Spore Sampler. Corresponding pediatric asthma data were recorded at a nearby medical hospital. Results indicated that the wet season showed higher pollen concentrations (82 pollen per cubic meter/day) than the dry season (53 pollen per cubic meter/day), and several pollen taxa were observed. An association between airborne pollen concentrations and pediatric asthma emergency room visits was suggested incorporating a threshold and lag period.     

Origin of the green iguana (Iguana iguana) invasion in the greater Caribbean Region and Fiji

Invasive populations of green iguanas (Iguanidae: Iguana iguana) are widely established beyond their native Central, South American, and Lesser Antillean range in various islands of the Pacific, Florida USA, and in the Greater Caribbean Region. Although widespread, information about these invasions is scarce. Here we determine the origin of invasive populations of green iguanas in Puerto Rico, Fiji, The Caymans, Florida USA, The Dominican Republic, the US Virgin Islands (USVI) of St. Thomas and St. Croix, and a U.S.A pet store. We sampled 120 individuals from these locations and sequenced one mitochondrial (ND4) and two nuclear (PAC and NT3) loci. We also include a preliminary characterization of population structure throughout Puerto Rico using six microsatellite loci to genotype individuals across 10 sampling sites. Comparing the genealogical relationships of all our samples to published sequencing data from the native range, we found that sampled populations were largely a product of populations from Colombia and El Salvador; two countries with multiple, industrial-size pet iguana farming operations. Notably, we found that haplotypes detected exclusively in the USVI and Puerto Rico’s outlying island of Vieques are closely linked to green iguanas native to Saba and Montserrat (Lesser Antilles); a clade not reported in the pet trade. Our population genetic analyses did not reveal isolation among sampling sites in Puerto Rico, rather the evidence supported admixture across the island. This study highlights the roles of the pet trade and lack of regulation in the spread of green iguanas beyond their native range.

     

Deagrarianisation and Forest Revegetation in a Biodiversity Hotspot on the Wild Coast,South Africa

Deagraianisation is a worldwide phenomenon with widespread social, ecological and economic effects yet with little consensus on the local or higher level causes. There have been contested views on the causes and consequences of deagrarianisation on South Africa’s Wild Coast, which is an international biodiversity hotspot. Using GIS, household interviews and ecological sampling, we compared the perspectives of current and former cultivators as to why some have abandoned farming, whilst also tracking the uses and woody plant cover and composition of fields abandoned at different periods. The GIS analysis showed that field abandonment had been ongoing over several decades, with a decline from 12.5 % field cover in 1961 to 2.7 % in 2009. The area of forests and woodlands almost doubled in the corresponding period. There was a distinct peak in field abandonment during the time of political transition at the national level in the early 1990s. This political change led to a decrease in government support for livestock farming, which in turn resulted in reduced animal draught power at the household and community level, and hence reduced cropping. The study showed it is largely the wealthier households that have remained in arable agriculture and that the poorer households have abandoned farming. The abandoned fields show a distinct trend of increasing woody biomass and species richness with length of time since abandonment, with approximately three woody plant species added per decade. Most local respondents dislike the increases in forest and woodland extent and density because of anxiety about wild animals causing harm to crops and even humans, and the loss of an agricultural identity to livelihoods and the landscape.     

Modeling Hurricane Exposure in a Caribbean Lower Montane Tropical Wet Forest: The Effects of Frequent,Intermediate Disturbances and Topography on Forest Structural Dynamics and Composition

Frequent intermediate disturbances can produce qualitatively different spatial heterogeneity and environmental variability than large infrequent disturbances, which facilitates the coexistence of disparate species types. We hypothesized that species coexistence will be maximized at sites exposed to recurring hurricanes with intermediate frequencies and effects. Consequently, we sought to determine if exposure vulnerability (EV) from three hurricanes with intermediate effects and frequencies (Ivan-2004, Dennis-2005 and Dean-2007), or the interaction between exposure and topography, could be used to explain forest structural dynamics and composition. We used data obtained in 2006 and 2012 from within 45, 25 × 25 m (2.8125 ha) permanent sample plots, established according to a randomized block design, and stratified according to elevation and aspect/sites (NE and SW facing ridges) in a tropical montane wet forest, John Crow Mountains, Jamaica. There was a significant reduction in basal area (BA) (14%), tree volume (10%), and density (26%) and there was a negative shift in the height profile of trees. Understory light (2008), stem density, and mortality increased with EV but decreased with aspect. The NE aspect/sites had higher EV after Dean and the other hurricanes. Consequently, BA, volume and density increased significantly for light-demanding species at the NE sites, but declined significantly overall with minimal changes at SW sites. Moreover, diversity was significantly higher at sites with higher EV for the three hurricanes. The frequent hurricanes with intermediate effects may have therefore maintained/increased spatial heterogeneity, which promoted the coexistence of species with disparate life histories at more exposed sites.     

海南霸王岭热带山地雨林森林循环与树种多样性动态

通过对海南岛霸王岭热带山地雨林的调查 ,研究了热带山地雨林树种多样性特征随森林循环的动态变化规律。结果表明 :( 1 )热带山地雨林森林循环不同阶段斑块在森林景观中所占的面积比例分别是 :林隙阶段 ( G)占 38.5 0 % ,建立阶段 ( B)占 2 8.5 0 % ,成熟阶段 ( M)占 2 7.0 0 % ,衰退阶段 ( D)占 6 .0 0 %。 ( 2 )热带山地雨林中乔木树种的密度随森林循环的变化趋势是由 G→B→M呈现出逐渐增加的趋势 ,以成熟阶段达到最大 ,而到衰退阶段又趋于下降。灌木树种则表现出 G阶段斑块的密度最大 ,B阶段的最小 ,从 B到 M有所增加 ,到 D又稍有下降。 ( 3)热带山地雨林中不同高度级和不同径级的树木的密度在森林循环的不同阶段表现出不同的增减趋势 ,其随森林循环过程呈现出的动态变化可能与不同阶段斑块内的空间、环境及物种生物学特性有关。 ( 4 )热带山地雨林中树木的平均胸径、平均高、平均胸高断面积、平均单株材积随森林循环过程呈现出不断增加的趋势 ,其中平均胸径和平均高随森林循环的变化较为平缓 ,而平均胸高断面积和平均单株材积之变化较为陡急。 ( 5 )热带山地雨林森林循环不同阶段的物种多样性指数不同 ,其中 G和 B阶段的物种丰富度和多样性指数值较接近 ,M阶段的物种丰富度达到最大 ,D阶段则最小。