Colony structure and sex allocation ratios in the ant <Emphasis Type="Italic">Temnothorax crassispinus</Emphasis>

Summary. We analyzed the impact of ecological parameters, such as nest density and nest site availability, on colony organization and investment patterns in two populations of the ant Temnothorax crassispinus, a parapatric sibling species of the well-studied T. nylanderi (Temnothorax was until recently referred to as Leptothorax (Myrafant); Bolton, 1993). As in T. nylanderi, sex allocation ratios were strongly associated with total sexual reproduction, i. e., nests with large sexual investment produced mainly female sexuals. Furthermore, nest site quality affected sex allocation ratios, with colonies from ephemeral nest sites producing a more male-biased sex allocation ratio than colonies from sturdy nest sites. In contrast to T. nylanderi, workers in colonies of T. crassispinus were mostly fullsisters both in a dense and a sparsely populated area, suggesting that colony fusion and colony usurpation are rare in this species. In addition, the presence of a queen in a local nest unit strongly influenced sex ratio decisions, in that these nests raised a more male biased allocation ratio compared to queenless nests. This also suggests that colony structure is more stable in T. crassispinus than in T. nylanderi. We conclude that sibling species, though often very similar in their morphology and ecological requirements, may nevertheless react very differently to ecological variation.Received 11 December 2003; revised 4 March 2004; accepted 19 April 2004.     

The role of patch area and habitat diversity in explaining native plant species richness in disturbed suburban forest patches in northern Belgium

Relatively easy measurable patch characteristics (especially habitat diversity measures) have proven to be valuable indicators of forest plant species richness in forest fragments of relatively undisturbed areas. Urban and suburban forest patches, however, are characterized by a specific landscape ecological context implying that specific processes may influence ecosystem functioning and hence that other abiotic indicators for plant diversity are more appropriate. We studied the relation between functional ecological plant species groups and suburban forest patch characteristics such as patch area, habitat diversity and isolation. Some components of species richness were related to the isolation of the patches. In contrast to previous similar large-scale fragmentation studies in more rural areas, further results stressed the overwhelming importance of patch area relative to habitat variables in determining species richness. This suggests (1) the occurrence of density-dependent species extinction processes in small forest patches; or (2) the existence of external deterministic factors which put a major constraint on species richness in small patches. We tend to support the latter hypothesis and propose forest disturbance and associated black cherry (Prunus serotina Ehrh.) invasion as such a possible external factor. Small forest patches may be more sensitive to disturbance and biological invasion due to various reasons. Hence large forest patches are to be preferred for plant conservation in the suburban area.     

Isolation determines patterns of species presence in highly fragmented landscapes

In fragmented landscapes, changes in habitat availability, patch size, shape and isolation may affect survival of local populations. Proposing efficient conservation strategies for such species relies initially on distinguishing the particular effects of those factors. To address these issues, we investigated the occurrence of 3 bird species in fragmented Brazilian Atlantic Forest landscapes. Playback techniques were used to collect presence/absence data of these species inside 80 forest patches, and incidence models were used to infer their occupancy pattern from landscape spatial structure. The relative importance of patch size, shape and surrounding forest cover and isolation was assessed using a model selection approach based on maximum likelihood estimation. The presence of all species was in general positively affected by the amount of surrounding habitat and negatively affected by inter‐patch distances. The joint effects of patch size and the surrounding landscape characteristics were important determinants of occupancy for two species. The third species was affected only by forest cover and mean patch isolation. Our results suggest that local species presence is in general more influenced by the isolation from surrounding forests than by patch size alone. We found evidence that, in highly fragmented landscapes, birds that can not find patches large enough to settle may be able to overcome short distances through the matrix and include several nearby patches within their home‐ranges to complement their resource needs. In these cases, patches must be defined as functionally connected habitat networks rather than mere continuous forest segments. Bird conservation strategies in the Atlantic forest should focus on increasing patch density and connectivity, in order to implement forest networks that reduce the functional isolation between large remnants with remaining core habitat.     

Remnants fragments preserve genetic diversity of the old forest lichen <Emphasis Type="Italic">Lobaria pulmonaria</Emphasis> in a fragmented Mediterranean mountain forest

Fragmentation represents a serious threat to biodiversity worldwide, however its effects on epiphytic organisms is still poorly understood. We study the effect of habitat fragmentation on the genetic population structure and diversity of the red-listed epiphytic lichen, Lobaria pulmonaria, in a Mediterranean forest landscape. We tested the relative importance of forest patch quality, matrix surrounding fragments and connectivity on the genetic variation within populations and the differentiation among them. A total of 855 thalli were sampled in 44 plots (400 m²) of 31 suitable forest fragments (beeches and oaks), in the Sierra de Ayllón in central Spain. Variables related to landscape attributes of the remnant forest patches such as size and connectivity and also the nature of the matrix or tree species had no significant effects on the genetic diversity of L. pulmonaria. Values of genetic diversity (Nei’s) were only affected by habitat quality estimated as the age patches. Most of the variation (76%) in all populations was observed at the smallest sampled unit (plots). Using multiple regression analysis, we found that habitat quality is more important in explaining the genetic structure of the L. pulmonaria populations than spatial distance. The relatively high level of genetic diversity of the species in old forest patches regardless of patch size indicates that habitat quality in a highly structured forest stand determines the population size and distribution pattern of this species and its associated lichen community. Thus, conservation programmes of Mediterranean mountain forests have to prioritize area and habitat quality of old forest patches.     

Impact of plant cover on the cavity‐nesting ant Temnothorax crassispinus

1. Plant communities influence the availability of important resources for ants, such as nest sites and food, as well as environmental conditions. Thus, plants affect the abundance and distribution of ants. 2. In a field experiment, the influence of plant cover on the settlement of nest sites and per‐capita productivity of sexual individuals by the ant Temnothorax crassispinus was analysed. In July 2014, in five areas with patches of alien balsam Impatiens parviflora, and another five of native balsam I. noli‐tangere, transects composed of artificial nests were established; the nest sites were situated inside patches of balsams, and outside of them. Four hundred and forty artificial nests were used. One year later, the nests were collected. 3. Colonies of the ants three times more often inhabited nest sites outside the patches of both balsams. Besides, colonies with queens were more frequently found in nest sites located away from balsams. The per‐capita productivity of sexual individuals was higher in nests collected in patches of balsam, and the colonies from patches of alien balsam produced a more female‐biased sex ratio. 4. In terms of the impact on the ant, no clear differences were found between the alien balsam and the native one. The most important factor affecting the fitness of ants in areas dominated by balsams is the presence of herbaceous plant cover rather than whether the plant is alien or native.     

Response of a raptor community to shrinking area and degradation of tropical rain forest in the south western Ghâts (India)

The influence of irregular or incomplete fragmentation and increasing degradation of natural rain forest on diurnal raptor community was studied in the northern part of the western Ghâts in southwestern India A census of mainly territorial breeding pairs on 400 ha sample quadrats was associated with a measure of the percent cover of the main habitat types and a degree of forest fragmentation including irregular patch shape and habitat heterogeneity
Four groups of 3-4 species were defined according to their decreasing tolerance to forest fragmentation and disturbance, from mostly open grassland species to interior forest specialists Habitat selection, density and sensitivity to landscape structure were investigated The community composition and dynamic of each habitat were the sum of these specific reactions The distribution of species along the succession of increasing fragmentation and forest degradation was thus found to be non random, but did not follow a nested subset pattern The density of forest species declined with forest patch size possibly because of the irregular patch shape, the increased edge effects and the consequent increase of linear distance for a bird to cover within its territory However, sensitivity to habitat structure and disturbance was found to be even higher than sensitivity to area per se The need to conserve the largest patches of little disturbed forest is emphasized, as well as the conservation value of woodlots-open habitat mosaics that are suitable for a different set of species     

Relationships between spatial configuration of tropical forest patches and woody plant diversity in northeastern Puerto Rico

The destruction and fragmentation of tropical forests are major sources of global biodiversity loss. A better understanding of anthropogenically altered landscapes and their relationships with species diversity and composition is needed in order to protect biodiversity in these environments. The spatial patterns of a landscape may control the ecological processes that shape species diversity and composition. However, there is little information about how plant diversity varies with the spatial configuration of forest patches especially in fragmented tropical habitats. The northeastern part of Puerto Rico provides the opportunity to study the relationships between species richness and composition of woody plants (shrubs and trees) and spatial variables [i.e., patch area and shape, patch isolation, connectivity, and distance to the Luquillo Experimental Forest (LEF)] in tropical forest patches that have regenerated from pasturelands. The spatial data were obtained from aerial color photographs from year 2000. Each photo interpretation was digitized into a GIS package, and 12 forest patches (24–34 years old) were selected within a study area of 28 km². The woody plant species composition of the patches was determined by a systematic floristic survey. The species diversity (Shannon index) and species richness of woody plants correlated positively with the area and the shape of the forest patch. Larger patches, and patches with more habitat edge or convolution, provided conditions for a higher diversity of woody plants. Moreover, the distance of the forest patches to the LEF, which is a source of propagules, correlated negatively with species richness. Plant species composition was also related to patch size and shape and distance to the LEF. These results indicate that there is a link between landscape structure and species diversity and composition and that patches that have similar area, shape, and distance to the LEF provide similar conditions for the existence of a particular plant community. In addition, forest patches that were closer together had more similarity in woody plant species composition than patches that were farther apart, suggesting that seed dispersal for some species is limited at the scale of 10 km.     

Soil millipede diversity in tropical forest patches and its relation to landscape structure in northeastern Puerto Rico

Uncontrolled urban development is threatening the survival of many terrestrial species worldwide, especially those with limited dispersal capabilities. Soil invertebrates account for a high proportion of the global biodiversity but there are few studies on how soil biodiversity varies with different parameters of landscape structure, especially in fragmented tropical habitats. Millipedes are among the most abundant detritivore invertebrates in the soil-litter macrofauna. We examined the relationships between soil millipede diversity and landscape structure in 12 forest patches of approximately 30 years of age, in northeastern Puerto Rico. Spatial characteristics of the landscape were determined from aerial color photographs and were digitized into a GIS package for analysis. Millipede species diversity and composition in these forest patches showed correlations with their surroundings (e.g. amount of forest in the matrix) and with the presence of vegetation corridors that connected to other forest patches, rather than forest patch attributes such as patch area and shape. Millipede species richness correlated negatively with the degree of isolation of forest patch (within 600 m radius), while species evenness correlated positively to the amount of forest within a 50 m buffer. Millipede species composition was related with the presence of vegetation corridors and the distance to the Luquillo Experimental Forest reserve. These findings show that a low degree of patch isolation, forested buffers, and presence of vegetation corridors need to be considered for the conservation and management of forest patches surrounded by urban developments, especially to protect terrestrial invertebrate species that require forested habitats for their dispersal.     

Internal Habitat Quality Determines the Effects of Fragmentation on Austral Forest Climbing and Epiphytic Angiosperms

Habitat fragmentation has become one of the major threats to biodiversity worldwide, particularly in the case of forests, which have suffered enormous losses during the past decades. We analyzed how changes in patch configuration and habitat quality derived from the fragmentation of austral temperate rainforests affect the distribution of six species of forest-dwelling climbing and epiphytic angiosperms. Epiphyte and vine abundance is primarily affected by the internal characteristics of patches (such as tree size, the presence of logging gaps or the proximity to patch edges) rather than patch and landscape features (such as patch size, shape or connectivity). These responses were intimately related to species-specific characteristics such as drought- or shade-tolerance. Our study therefore suggests that plant responses to fragmentation are contingent on both the species'' ecology and the specific pathways through which the study area is being fragmented, (i.e. extensive logging that shaped the boundaries of current forest patches plus recent, unregulated logging that creates gaps within patches). Management practices in fragmented landscapes should therefore consider habitat quality within patches together with other spatial attributes at landscape or patch scales.     

Forest expansion or fragmentation? Discriminating forest fragments from natural forest patches through patch structure and spatial context metrics

In forest–grassland mosaics, patches can result from two processes: forest expansion over grassy ecosystems and forest fragmentation. We tested the hypothesis that patches produced by these processes differed in structure and spatial context in a forest–grassland mosaic in the southern Brazilian highlands. We compared a present‐day land cover map with a past vegetation map to identify natural forest patches and forest fragments. Patches were described according to structure (size, core area and shape metrics) and spatial context (distance from roads and urban areas, edge contrast). Principal component analyses were used to examine gradients of patch types, and differences were tested by analysis of variance with randomization test. We found 878 natural patches and 214 fragments. Natural forest patches, riparian forest patches and forest fragments differed in structure and spatial context. In comparison to natural forest patches, fragments tend to be larger, with larger core areas, and more irregular and complex in shape. Fragments are situated in a different spatial context, tending to be closer to roads and urban areas and to present higher edge contrast. Riparian natural forest patches are similar to natural forest patches, except for shape. The smaller area and regular shape of natural patches probably result from the mechanisms involved in nucleus formation in the grassland matrix and from current grassland management. Natural patches are less exposed to some anthropogenic stresses, since most of them remain in a native grassland matrix context. Our results show that inferring process from pattern is not trivial, because different processes – forest expansion and forest fragmentation – may lead to either distinct or similar patterns of patch shape and spatial context. Studying patch structure and spatial context may then provide further insight into understanding changes in vegetation pattern at landscape scale, and in disentangling the effects of concurrent processes.     

济南城市森林景观生态格局

城市森林景观生态格局研究不仅是城市森林系统规划与城市生态建设的基础和前提,而且是优化城市空间结构、充分发挥城市森林生态功能以及创建生态宜居环境的重要途径和手段.本研究以RS和GIS技术为支撑,通过总体景观生态格局定量分析和梯度分析等研究方法,采用10个景观指数从斑块水平和景观水平两方面,对济南市建成区城市森林景观生态格局进行定量分析,并提出优化对策.结果表明: 济南市建成区城市森林覆盖率为15.8%;城市森林总体景观生态格局在景观水平上表现为城市森林景观斑块类型较齐全、景观破碎化程度较大、各类型城市森林所占面积存在差异、以大斑块为主且同种斑块高度连接,在斑块类型水平上表现为生态公益林以大斑块为主且占优势地位、风景游憩林形状较规则且以大中型斑块为主、道路林及附属林形状复杂且以小斑块为主、生产经营林缺乏;在斑块类型水平上,以风景游憩林为主导类型、生态公益林斑块面积最大、道路林及附属林破碎度大,在景观水平上,城市中心森林景观破碎度大、人为干扰严重、景观形状复杂;在城市森林景观生态格局分析基础上,提出“一环二网、三片四轴、多点棋布”的济南市城市森林生态网络构建方案,从而加强各类型城市森林的连接度,发挥大尺度生态系统的整体生态效益.     

Should I stay or should I go now? Patch use by African army ant colonies in relation to food availability and predation

Army ant colonies do not have permanent nests but frequently move to new patches. Local food depletion is considered the ultimate cause of this nomadic behaviour, but the proximate causes are not well understood. We tested if and how patch departure time of the aboveground-hunting army ant Dorylus molestus under field conditions is influenced by food availability and nest attacks by predators. In the first food supplement experiment, colonies receiving additional food throughout an entire nest stay did not reside in their nests for longer periods than control colonies. However, the distances travelled by colonies after nest stays during which colonies obtained food were shorter than those before these nest stays, indicating that colonies do assess food availability and avoid moving too far away from patches of high food availability. In the second food supplement experiment, in which colonies were given even larger amounts of food in the second half of their nest stay to mimic a rich unpredictable food source that these highly polyphagous predators are likely to encounter sometimes, patch departure times likewise did not differ between treated and control colonies. Either patch departure time is independent of food availability or there is another, as yet unappreciated proximate cause of colony movements in this species which we were unable to control for in our field experiments. One possibility is that encounters between neighbouring colonies influence patch departure time. In the experiment on the effect of predation, colonies responded to simulated nest attacks by mammals by leaving nests almost instantaneously and thus much earlier than control colonies. Rapid nest evacuation is likely a response to minimize the probability of repeat attacks by predators which cannot be repelled in other ways. Future studies will be necessary to definitively determine whether food availability influences patch departure times and to elucidate the consequences of colony encounters.     

Fragmentation in eucalypt woodlands promotes nest‐tree occupancy by a despotic species,the noisy miner (Manorina melanocephala)

The effects of habitat fragmentation as a threat to biodiversity are well known; decreased connectivity can potentially influence population processes and dynamics, resulting in smaller, isolated populations that may not function optimally. However, fragmentation may also increase the amount of edge or ecotone habitat available to open country species, benefiting their populations and enabling them to dominate remnant habitats. Noisy miners (Manorina melanocephala) are one such species, occupying eastern‐Australian eucalypt woodlands. They are considered a ‘despotic’ species, in that their presence negatively impacts woodland avifauna biodiversity due to their aggressive exclusion of other taxa from occupied areas. Despite this well‐known impact, little information exists on the patterns of nest‐tree occupancy by noisy miners within eucalypt woodlands. In the current study, we explored the patterns of nest‐tree occupancy by noisy miners across two successive years, aiming to identify preferences for breeding areas relative to vegetation structure. Our results show that both habitat fragmentation and the characteristics of individual eucalypt trees in an area influenced nest‐tree occupancy. Noisy miners constructed nests in trees near the edge of woodland patches more often than expected. Moreover, the nest tree chosen was a eucalypt that was significantly smaller than randomly selected trees from the surrounding area. The results highlight the importance of habitat management measures that may reduce the suitability of woodland patches as nesting sites for this species, in order to mitigate the severe effects of this despotic edge specialist.     

The effects of edge, fragment size and degree of isolation on avian species richness in highly fragmented forest in West Africa

Almost nothing is known of the effects of forest fragmentation on bird diversity within the heavily degraded and fragmented forest remnants in West Africa. We examined the effects of edge, fragment size and isolation on bird species richness in southwestern Nigeria where forest fragmentation is pronounced. In total, 122 km of line transects were used to survey birds and vegetation within 45 forest patches between January 2000 and March 2002: 197 species were recorded. Avian species number and total counts in forest patches were unrelated to fragment area (within the observed range of 14–445 ha), but were negatively influenced by degree of isolation and increasing distance from the edge. As the total area of forested land within 15 km of a patch fell from 4 to 0%, so 21% of species were lost. In total, six and zero species (of 154 recorded more than once) were consistently recorded in the larger and smaller forest fragments, respectively, and four and two bird species were consistently recorded in unisolated and isolated forest fragments, respectively, suggesting that the addition of ‘edge’ species did not compensate for loss of species sensitive to fragmentation. Diversity index was not affected by either fragment area or degree of isolation, but decreased with distance from the edge. When individual species counts were considered, 68% of species (n = 62) showed no significant effect of distance to edge. Of those 20 species which showed an effect, 12 were less common close to the edge. Most species (65%) did not respond significantly to increasing isolation but of those 22 species that did, 20 were less common in more isolated fragments. Ninety‐seven per cent of species showed no significant response to area. As avian diversity and species composition, but not species number, were apparently insensitive to forest fragmentation, our findings suggest that fragmentation reduces the probability of occurrence of a wide range of West African bird species, rather than a subset of fragmentation‐sensitive species. The greater apparent sensitivity of present‐day West African forest bird communities to fragmentation rather than patch size might reflect previous extinctions of area‐sensitive species. Minimizing further forest fragmentation might be the most effective means of conserving avian diversity in current West African landscapes where most remaining forest patches are small (i.e. < 500 ha).     

The influence of hybridization on colony structure in the ant species Temnothorax nylanderi and T. crassispinus

The parapatric sibling ant species Temnothorax nylanderi and T. crassispinus hybridize in the contact zone in the Franconian Jura, Southern Germany. Aim of our study was to investigate the impact of hybridization on colony composition and fitness. We classified colonies as either ‘pure’ or containing hybrids by determining their allozyme pattern at GPI, an enzyme that is fixed for different alleles in the two parental species, and quantified their reproductive output. Most colonies with hybrid workers had a T. crassispinus queen. Colonies with heterozygous, hybrid workers produced more young workers than colonies of the parental species but similar numbers of male and female sexuals. Female sexuals from colonies with heterozygous workers had a significantly lower weight than female sexuals from pure colonies. Only a single reproductive queen was found to be heterozygous, suggesting reduced fitness of hybrid queens. As in the parental species, hybrid colonies appear to be frequently taken over by alien queens, which obscures the genetic colony structure. Received 6 April 2006; revised 10 June 2006; accepted 15 June 2006.     

Coping with Forest Fragmentation: The Primates of Kibale National Park,Uganda

A goal of conservation biology is to determine which types of species are most susceptible to habitat disturbance and which types of disturbed habitats can support particular species. We studied 20 forest fragments outside of Kibale National Park, Uganda, to address this question. At each patch, we determined the presence of primate species, tree species composition, patch size, and distance to nearest patch. We collected demographic, behavioral, and dietary data for Abyssinian black-and-white colobus (Colobus guereza). Black-and-white colobus and red-tailed guenons (Cercopithecus ascanius) were in almost all fragments; Pennant's red colobus (Procolobus pennantii) and chimpanzees (Pan troglodytes) were in some fragments; and blue monkeys (Cercopithecus mitis) and gray-cheeked mangabeys (Lophocebus albigena) were absent from all fragments. No species characteristics—home range, body size, group size, or degree of frugivory—predicted the ability of species to live in patches. No characteristics of patches—area, distance to the nearest patch, distance to Kibale, or number of food trees present—predicted the presence of a particular species in a patch, but distance to Kibale may have influenced presence of red colobus. Black-and-white colobus group size was significantly smaller in the forest patches than in the continuous forest of Kibale. For a group of black-and-white colobus in one patch, food plant species and home range size were very different from those of a group within Kibale. However, their activity budget and plant parts eaten were quite similar to those of the Kibale group. The lack of strong predictive variables as well as differences between other studies of fragmentation and ours caution against making generalizations about primate responses to fragmentation.     

Forest species in an agricultural landscape in the Netherlands: Effects of habitat fragmentation

Abstract. For 312 forest patches on sandy soils in the Netherlands, effects of fragmentation are studied of forest habitat in the past on the present occurrence of forest plant species. Using regression techniques, the numbers of forest edge, interior, zoochorous and anemochorous species, as well as occurrence of 24 individual species were related to patch area and connectivity measures. Connectivity was defined as the amount of forest habitat around patches within three zones up to 1000 m. Plant categories were distinguished by habitat type and dispersal mechanism. The results showed that number of total species and number of species of all habitat and dispersal categories increased with area. The occurrence of ten individually studied species were also positively related to area. Most of them were interior species. The number of zoochorous species increased with increasing connectivity. Also occurrence of ten individually studied species were affected by connectivity. Interior zoochorous species showed the highest percentage of affected species. The relationship of interior, animal-dispersed plants to connectivity can be explained by the limited distances covered by their dispersal agents (forest birds and ants) in a non-forest habitat. Also, some anemochorous plants appeared to be affected by connectivity, especially those with heavy seeds and potentially short distance dispersal. As not all species within a certain dispersal or habitat category react similar to area or isolation, it is suggested that differences in underlying processes of fragmentation such as local extinction and colonization need more focus.     

黑龙江林口林业局森林景观格局特征

以黑龙江林口林业局1∶50000林相图作为基本信息源,利用地理信息系统软件ArcView和景观结构分析软件Fragstats,从景观格局的总体特征、景观破碎度、景观形状指数、分形维数和平均最近距离等方面,对该林业局的景观格局进行了分析.结果表明:该林业局以森林景观为主体(56.74%),居民点和农田景观也占有较高比例,而沼泽、灌木、荒山荒地、河流、迹地和裸地等景观零星分布于森林景观中;该林业局的森林景观主要以人工针叶纯林(40.47%)和天然蒙古栎林(20.96%)为主,斑块分布集中、形状复杂、边缘褶皱度高.人工林与天然林的面积基本相等,但破碎度较大、斑块形状相对简单、斑块分布较集中,软阔叶林及硬阔叶林斑块分别占11.89%和7.38%.研究表明,该林业局的森林景观受人为干扰程度过大,景观结构不合理,要实现林业的可持续发展,必须对景观斑块结构进行调整.     

The occurrence of the red-handed howler monkey (Alouatta belzebul) in amazonian savannas is related to forest patch area and density of flooded area palms

All Neotropical primates are arboreal and thus depend on forests for their survival. Arboreality puts many Neotropical primates at risk of extinction due to the high rates of deforestation in the tropics. We assessed the influence of vegetation structure and forest patch attributes on the occurrence of the threatened red-handed howler monkey (Alouatta belzebul) in an Amazonian savanna. Using a sample of 38 forest patches in a region of approximately 2000 km² in the state of Amapá, northern Brazil, we used logistic regression to find the best predictors of the occurrence of A. belzebul. We assessed patch area, patch isolation, the proportion of seasonally flooded forest in the patch, the density of flooded area palms, forest height, canopy cover, and diameter at breast height of trees. Patch area and palm density were the best predictors of the occurrence of A. belzebul in forest patches, both having a positive effect on the probability of occurrence. Our results indicate that areas of flooded forest in forest patches may be keystone habitats for A. belzebul living in Amazonian savannas. The observed effect of palm density on A. belzebul suggests that this variable is useful for planning conservation actions, including the selection of areas for protection and management strategies for areas inhabited by this primate.     

Impacts of forest fragmentation on species composition and forest structure in the temperate landscape of southern Chile

Aim Few studies have explicitly examined the influence of spatial attributes of forest fragments when examining the impacts of fragmentation on woody species. The aim of this study was to assess the diverse impacts of fragmentation on forest habitats by integrating landscape‐level and species‐level approaches. Location The investigation was undertaken in temperate rain forests located in southern Chile. This ecosystem is characterized by high endemism and by intensive recent changes in land use. Method Measures of diversity, richness, species composition, forest structure and anthropogenic disturbances were related to spatial attributes of the landscape (size, shape, connectivity, isolation and interior forest area) of forest fragments using generalized linear models. A total of 63 sampling plots distributed in 51 forest fragments with different spatial attributes were sampled. Results Patch size was the most important attribute influencing different measures of species composition, stand structure and anthropogenic disturbances. The abundance of tree and shrub species associated with interior and edge habitats was significantly related to variation in patch size. Basal area, a measure of forest structure, significantly declined with decreasing patch size, suggesting that fragmentation is affecting successional processes in the remaining forests. Small patches also displayed a greater number of stumps, animal trails and cow pats, and lower values of canopy cover as a result of selective logging and livestock grazing in relatively accessible fragments. However, tree richness and β‐diversity of tree species were not significantly related to fragmentation. Main conclusions This study demonstrates that progressive fragmentation by logging and clearance is associated with dramatic changes in the structure and composition of the temperate forests in southern Chile. If this fragmentation process continues, the ability of the remnant forests to maintain their original biodiversity and ecological processes will be significantly reduced.