Forest Patch Area Research Articles

Distribution and drivers of critical hibernacula for the timber rattlesnake Crotalus horridus in Illinois, USA

The dependency on hibernacula for extended periods presents terrestrial reptiles with the challenge of locating thermally adequate hibernacula each winter. Defining the habitat characteristics of hibernacula is crucial for understanding the overwintering requirements and distributions of hibernacula-dependent reptiles, alongside identifying habitats which warrant special conservation concern. Our objectives were to identify the overwintering habitat characteristics of the imperiled timber rattlesnake Crotalus horridus in Illinois, USA, and to determine the distribution of likely hibernacula habitats throughout the state. Due to the initial sparsity of hibernacula records in Illinois, we adopted an iterative habitat suitability modeling process consisting of 3 distinct rounds of Maxent construction and revision. Each round was informed with updated information from model-guided surveys or by building rapport with in-state naturalists and researchers who knew of additional hibernacula locations. We created our final model using 36 hibernacula and identified slope angle (indicative of rock outcrops and shallow soils), topographical position index, forest patch area, and aspect (decomposed into 2 linearized variables: southness and eastness) as important drivers of C. horridus hibernacula habitat in Illinois. Together, the 5 variables and site surveys suggest the suitable overwintering habitat for C. horridus in Illinois is located on south- to southwest-facing outcrops on upper slopes and ridges of larger forest patches. Such habitat is distributed primarily in southern Illinois and throughout the Mississippi River and Illinois River border counties. Our study adds to the current understanding of the species’ overwintering requirements and provides a foundation for future ecological studies, management, and survey efforts throughout Illinois.

The preservation of old forests in southwest China is closely linked to the presence of ethnic minorities

Sacred forests are increasingly disappearing due to increasing land pressure and a decline in cultural values. Protecting the remaining sacred forests plays a crucial role in preserving biodiversity. The existence of remaining old forests often related to local people and their culture, but this relationship has rarely been quantified at large regional scales. This study analyzes the relationship between old forest and ethnic minorities based on the location of the old forest at a high spatial resolution (2 m). We found a significantly positive correlation (p < 0.01) between the proportion of ethnic minority population and old forest patch number, area, aggregation, and maximum patch area. However, there was no correlation with the connectivity of the old forest (p = 0.14). We further show that both environmental and anthropogenic factors are important for the distribution of old forests. Hydrothermal conditions contribute to the growth of forests, and local ethnic customs and the corresponding ecological wisdom contributes to the preservation of old forest remnants (r = 0.12, p < 0.05). Our findings highlight the significance of social dimensions for the conservation of old forests. We encourage that forest management should consider the role of indigenous people and their cultural wisdom for a better conservation and restoration of degraded ecosystems.

Combined effects of urban forests on land surface temperature and PM2.5 pollution in the winter and summer

The interactions and mechanisms among green space patterns, air quality and thermal environments are not well understood. This study aimed to identify co-benefits of urban forest pattern indicators (UFIs) in reducing PM2.5 on highly polluted winter days and providing cooling on hot summer days. We selected urban core areas of seven cities in Jiangsu Province, China as a study case, and obtained data from MODIS, Landsat 8, Sentinel-1 and Sentinel-2 remote sensing images and products. The results showed that on a heavily polluted winter day, all four UFIs (area, patch density, mean shape index and aggregation index) had significantly negative total effects on PM2.5. The effect of area on PM2.5 was suppressed by LST, and other UFIs’ effects on PM2.5 were partially or fully mediated by LST. On a hot summer day, all four UFIs except patch density had significantly negative total effects on LST. The effect of patch density on LST was suppressed by PM2.5, and the effects of other UFIs on LST were partially mediated by PM2.5. This study indicated that increasing area, shape complexity and aggregation level of urban forest patches could reduce PM2.5 on highly polluted winter days and provide cooling on hot summer days.

Effects of Shading on the Growth and Photosynthetic Fluorescence Characteristics of Castanopsis hystrix Seedlings of Top Community-Building Species in Southern Subtropical China

Castanopsis hystrix is a major community-building species in the top communities of southern subtropical China, with a high natural regeneration capacity. However, excessive logging and the introduction of exotic tree species have substantially reduced the area of natural forest patches of Castanopsis hystrix, and seedling regeneration is essential for the long-term continuation of Castanopsis hystrix populations. To explore the effects of light intensity on the seedling emergence and early growth of Castanopsis hystrix, shading experiments were conducted under four shading treatments (0%, 40%, 60%, and 80%). The growth, biomass accumulation, and distribution, the quality index of seedlings, the morphology and structure of the root systems of seedlings, and the leaf chlorophyll content and chlorophyll fluorescence properties of seedlings under different shading treatments were analyzed. The results displayed the following: (1) Shade intensity impacts growth of Castanopsis hystrix seedlings and biomass allocation, with optimal results observed at 60% shade, leading to the promotion of organic matter production in leaves and the limitation of stem growth. (2) Using a multi-indicator composite index, it was determined that seedling quality for Castanopsis hystrix peaks at 60% shade intensity. (3) Shade significantly impacts the morphology and structure of Castanopsis hystrix’s root system, with most root characteristics peaking at 60% shade, indicating a substantial increase in root development compared to no-shade conditions. (4) The D-values indicated the most suitable shade intensity for seedling growth to be 60%, suggesting that Castanopsis hystrix seedlings are sensitive to light and excessive light can be detrimental to their growth. (5) The 60% shade treatment showed the maximum values of chlorophyll fluorescence characteristics and photochemical activity, with variations in energy conversion efficiency and dissipation reflected in parameters like photochemical burst coefficient (qP), photochemical burst coefficient (qN), the actual photometric yield of PSII under light acclimation (YII), and the maximum photosynthetic electron transport rate in photoinhibition (ETR), thereby supporting seedling growth and maintaining the normal function of photosynthetic organs. In conclusion, 60% shade treatment can effectively improve the growth and photosynthetic characteristics of Castanopsis hystrix seedlings and promote the accumulation of nutrient elements, ultimately promoting their growth.

The requirements of three co-existing woodpecker species Picidae in relation to forests' features in the agricultural landscape of SE Poland

The occurrence of woodpeckers in European forests depends on many forest stand characteristics. During the study conducted in 2013 in the agricultural landscape of SE Poland (in an extremely deforested area with a 5% share of forest area), the habitat requirements of Middle Spotted Woodpecker Dendrocoptes medius, Great Spotted Woodpecker Dendrocopos major and Syrian Woodpecker Dendrocopos syriacus were described. For this purpose, the degree of occupation by individual species of 73 forest patches was assessed over an area of 355 km2. To determine the habitat requirements of the woodpecker species, a set of 7 parameters characterizing the studied forests and their surroundings were determined, viz. forest patch area, average age of the tree stand, etc.). Generally, the Syrian Woodpecker inhabited small forest patches surrounded by a significantly larger proportion (2.3–5.6%) of orchards, compared to forests uninhabited by this species. The most important factors that positively influenced the occurrence of the Middle and Great Spotted Woodpeckers were the forest patch size, average age of the forest patch stand, and area of forest stands aged older than 80 years. The Great Spotted Woodpecker preferred forest patches with an area exceeding 15 ha, but the Middle Spotted Woodpecker occurred only in forest patches over 42 ha. Such minimum forest patch areas should be considered essential for protecting the two mentioned species in a heavily deforested landscape. Small-sized forest patches should also be protected, enabling refuge for the Syrian Woodpecker. Keywords: bird conservation strategy, forest management, habitat selection, primary cavity nesters, rural landscape, woods, woodpeckers, SE Poland

Zmiany powierzchni leśnych na terenie Parku Krajobrazowego Puszcza Zielonka w ostatnich 180 latach w aspekcie krajobrazowym

The article presents the results of research on changes in forest areas in the PuszczaZielonka Landscape Park. An analysis of forest area transformations was carried out with the use of landscape metrics. Archival cartographic material in the form of topographic maps in the scale of 1 : 25 000, coming from four different periods (1830, 1890, 1940 and 1979/80) and a generalized Database of Topographic Object (BDOT) dated 2010, were used for the research. The result of the research are quantitative and qualitative characteristics of changes in the area and the spatial layout of the forest areas and a model of landscape processes taking place in the Puszcza Zielonka Landscape Park. The first analyzed period (1830–1890) was characterized by a small regression of forest area (index of changes WD = ‒0.05), whereas fragmentation and dissection of forest patches prevailed. The second period (1890–1940), despite the slight increase in forest areas (WD = +0.03), was characterized by a decrease in the number of patches and a reduction of their borders’ length. In the third period (1940-1979), the landscape increment process (WD = +0.27), mainly related to the filling of non-forested areas within forest complexes, prevailed. After 1979, the direction of changes was similar but on a much smaller scale (WD = +0.04).

Effects of Light Intensity on Seedling Emergence and Early Growth of Liquidambar formosana Hance

Liquidambar formosana Hance is a common deciduous broad-leaved tree known for its fast growth rate and adaptability. However, excessive logging has substantially reduced the area of natural forest patches of L. formosana, and seedling regeneration is essential for the long-term continuation of L. formosana populations. To explore the effects of light intensity on the seedling emergence and early growth of L. formosana, a controlled experiment was conducted under three light-intensity treatments (20%, 60%, and 100% of full sunlight, i.e., the photosynthetic photon flux densities (PPFDs) were 223.93 ± 7.54, 670.94 ± 30.14, and 1119.61 ± 23.19 μmol·m−2·s−1, respectively). The seedling emergence percentage, mean germination time, germination synchrony, vitality index, survival percentage, emergence index, morphological characteristics, and biomass allocation under different light intensities were analyzed. The seedling vitality index and survival percentage significantly differed among the treatments and were the lowest under 20% light intensity. With increased light intensity, the seedling mean germination time and germination synchrony increased and then decreased, and the opposite was true for the emergence index. With the increased light intensity, the seedling height, stem diameter, and root length significantly increased. The total, root, stem, and leaf biomasses reached maximum values under full sunlight. With the increased light intensity, the leaf biomass ratio increased, whereas the root biomass, stem biomass, and root–shoot ratios decreased. Our results indicated that the poor light environment under the canopy is not conducive to the survival and growth of L. formosana seedlings and may be among the primary reasons for low seedling establishment.

Divergent responses of Picea crassifolia Kom. in different forest patches to climate change in the northeastern Tibetan Plateau

Global climate changes have significantly affected tree growth and forest structures and functions in some arid and semi-arid regions, which are becoming warmer and wetter. Due to natural factors such as climate and terrain, some tree species may form different forest patches at the edges of their distribution areas. However, how forest patches of various sizes respond to climate change is unclear. In this study, we collected 203 tree cores from six different sizes of forest patches at the edge of the distribution area of Picea crassifolia Kom. in the northeast Tibetan Plateau. And we used the dendrochronology method to study the response of tree growth and resilience in different forest patches to climate change from 1961 to 2020. We simultaneously measured the contents of non-structural carbohydrates (NSC), total nitrogen and total phosphorus of tree needles. Our results showed that the growth of trees in small- and medium-size forest patches (0.8–18.6 ​ha) has increased significantly. The early growing season (May–July) minimum temperature was the most important climate factor driving the growth of small- and medium-sized patch trees. The early growing season maximum temperature was the most important climate factor that inhibited the growth of trees in the largest patches (362.8 ​ha). The growth of individual trees in medium forest patches was better and the correlation with annual minimum temperature, maximum temperature, precipitation, actual evapotranspiration, and palmer drought severity index was stronger. The higher NSC content, stronger photosynthesis, and higher nitrogen utilization efficiency in leaves might be one of the reasons for the better growth of trees in moderate forest patches. In extreme drought years, as the forest patch area increased, the overall trend of tree growth resistance showed a unimodal pattern, with the highest at a forest patch area of 7.1 ​ha, while the overall trend of tree growth recovery was opposite. Therefore, we should strengthen the management of trees in large forest patches to cope with climate change.

西辽河上游生境质量时空演变特征与影响机制

PDF HTML阅读 XML下载 导出引用 引用提醒 西辽河上游生境质量时空演变特征与影响机制 DOI: 10.5846/stxb202112243648 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划（2016YFC0503603） Characteristics of spatio-temporal evolution and influence mechanism of habitat quality in the upper reaches of the West Liaohe River Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:西辽河上游是我国辽河流域的重要水源地，其生境质量的好坏关系到下游流域生态安全和人类福祉。然而针对西辽河上游生境质量及其影响机制的研究还有待深入。基于ArcGIS软件、InVEST模型，定量分析了西辽河上游1980-2018年土地利用和生境质量的时空演变特征；并进一步探究了西辽河上游生境质量变化的主要驱动因子。结果表明：（1）1980-2018年，西辽河上游草地面积较1980年下降了21.93%，其中大部分转化为林地（7719.09 km2）、耕地（6014.90 km2）和裸地等（3025.71 km2）等，各斑块的空间分布异质性增加；尽管研究期内，林地面积较基期大幅度提升了48.67%，但全区域平均生境质量指数由0.74下降到0.72。（2）该地区无论在区域本底环境和区域社会经济发展水平上，均对于西辽河上游的生境质量改善产生了积极作用，年均气温（0.218）、降水（0.229）、地区生产总值（0.850）和受教育程度（0.132）与生境质量指数呈现较为明显的正相关关系；然而，本地区城镇化速率（-1.137）、景观分离度指数（-0.532）和道路的扩张（-0.394）与生境质量指数呈现较为明显的负相关，可见快速的城镇化所引起的人类活动加剧是导致区域生境质量的下降的重要诱因。本研究旨在为平衡区域发展和生态保护，为以半干旱农牧交错带地区为代表的生态脆弱区可持续发展提供科技支撑。 Abstract:The upper reaches of the West Liaohe River is one of the most important water sources of the Liaohe River Basin in China, and the quality of its habitat is directly related to the ecological security and human well-being of the downstream basin. However, the relevant studies on the habitat quality about the upper reaches of the West Liaohe River is still relatively scarce, and further studies on its influencing mechanism also needs to be conducted. Based on the models of ArcGIS and InVEST, our study quantitatively analyze the spatial and temporal evolution characteristics of land use and habitat quality on the upper reaches of the West Liaohe River from 1980 to 2018, what is more, we also further explored the main driving factors which caused the habitat quality changes during the 38 years. Several results have showed that:(1) From 1980 to 2018, the grassland patches area in the upper reaches of the West Liaohe River decreased by 21.93% compared with that in 1980, most of which has been converted into forest (about 7719.09 km2), farmland (about 6014.90 km2) and bareland (about 3025.71 km2). Meanwhile, the spatial heterogeneity of the land use patches in the study area has increased. Although the area of forest land patches increased by 48.67% compared with the that in 1980, the average habitat quality index of the whole area has dropped from 0.74 to 0.72. (2) Over the past 38 years, both the regional background environment and the level of regional social and economic development had played a positive role on the improvement of habitat quality in the upper reaches of the West Liaohe River. The factors, such as the annual average temperature, the precipitation, and the level of education, have shown significantly positively correlated with the habitat quality index, which regression coefficients were described as 0.218, 0.229, 0.850, 0.132 respectively. However, the factors, such as the urbanization rate, the splitting index, and the expansion of urban roads, have showed a negative relationship with the habitat quality index, which regression coefficients were expressed as -1.137, -0.532, and -0.394 respectively. It could be seen that the intensification of human activities caused by the rapid urbanization is an important inducement leading to the deterioration of the regional habitat quality. The study aimed to balance regional development and ecological protection about the upper reaches of the West Liaohe River. Moreover, it aimed to provide scientific and technological support for the sustainable development of ecologically fragile areas represented by semi-arid agro-pastoral ecotone. 参考文献 相似文献 引证文献

The effect of habitat amount on flight‐related traits in the butterflyHamadryas februais sex‐dependent

AbstractMobility in flying animals can be assessed by variations in morpho–ecological traits such as body, thorax and wing sizes, wing shape and the proportion between body mass and wing area. Habitat loss and fragmentation can promote phenotypic plasticity and microevolutionary divergencies in natural populations. In this context, sexual differences in physiology and behaviour can impose different selection pressure on morphological aspects related to flight.We evaluated the relative impact of forest patch area and habitat amount in shaping flight‐related morpho–ecological traits of the tropical butterflyHamadryas februa. We find a marked sexual dimorphism in the species, with females being larger, having larger thorax, higher wing loadings and larger wing total area than males. These trait values indicate females as the more dispersive sex. We show that habitat amount modulates body mass allocations in both sexes, leading to an increase in thorax mass with decreasing habitat amount. The effect of habitat amount was more pronounced in females, which increased total mass and wing loading while decreasing thorax allocation with decreasing habitat amount. This outcome suggests that females increase abdominal mass in response to a reduction in habitat amount. The focal forest patch increasing area was linked to increases in hindwing lengths in both females and males.We advocate that both landscape metrics (i.e., habitat amount and patch area) should be considered in studies evaluating landscapes' impacts on insect mobility. We discuss results in terms of the species' sexual differences in flight behaviour and the relative importance of both landscape metrics.

Area Threshold Interval of Urban Forest Patches Required to Maintain the Synergy between Biodiversity Conservation and Recreational Services: Case Study in Beijing, China

Promoting sustainable urban development is crucial in light of upcoming environmental change and population expansion. Urban forests play a key role in transporting ecosystem services to urban areas. They not only offer a crucial biological setting for preserving urban biodiversity, but they also give recreation dwellers access to a variety of urban opportunities and ensure their spiritual and cultural needs are met. Maintaining urban biodiversity and offering recreation services have trade-offs and synergies, and both were highly connected with the size of an urban forest patch. Six districts in Beijing’s central urban area were chosen for this study to serve as the research objective. First, the MSPA model was employed to conduct a thorough scientific analysis of the pattern and distribution characteristics of urban forests in Beijing’s central urban area. Second, the recreation services were quantified by merging many sources of big data, the urban forest biodiversity preservation services were assessed using the InVEST model, and the spatial heterogeneity of the two services was examined. In conclusion, the coupling coordination degree model was utilized to calculate the crucial threshold interval between urban biodiversity service and recreation service for urban forest patch area. The findings indicated that the ideal urban forest patch scale for achieving the synergy of the two types of services was an area between 0.5 and 1 hectare. The outcomes can serve as a scientific foundation for urban forest planning and management in the future, assist in realizing the synergistic growth of the two services, as well as support the improvement of ecosystem services and the ecological welfare of people.

Effects of Landscape Configuration on the Body Condition of Migratory and Resident Tropical Birds

Landscape structure and configuration may affect bird body condition, with contrasting effects on resident and migratory species. There is little empirical evidence to support this hypothesis in tropical regions, where land-use change poses a major threat to biodiversity. We aimed to assess the effects of landscape structure and configuration on the body condition of neotropical migrant and resident bird species. We compiled body condition data (using the scaled mass index) of nine bird species (five resident and four migratory). We characterized landscape structure and configuration at 26 localities. We evaluated the effects of landscape metrics on bird body condition using Bayesian linear mixed models. The landscapes in our study largely varied in forest, crop, and grassland cover, as well as in landscape metrics. When we examined migrant birds, we found a positive effect of landscape connectivity and crop cover on body condition. Similarly, body condition of resident birds was positively affected by connectivity and crop cover, but also by forest patch area and capture day. Changes in landscape structure and configuration may indirectly alter the access to resources, causing additional energy expenditures, leading to a deteriorated body condition. Conversely, landscape heterogeneity may have a positive effect on bird body condition. Therefore, we recommend maintaining connectivity and complementary resources in the landscape.

Habitat Quality, Not Patch Size, Modulates Lizard Responses to Habitat Loss and Fragmentation in the Southwestern Amazon

As deforestation frontiers expand in the tropics, understanding species responses is critical to inform efficient land-use management policies. Here we evaluated lizard responses to changes in landscape, habitat patch, and quality in a deforestation frontier in southwestern Brazilian Amazonia. We first considered overall lizard assemblages and then two species subgroups of contrasting thermoregulation strategies. We sampled lizards at 21 forest patches (42–7,035 ha) subject to moderate habitat disturbance (e.g., cattle intrusion and selective logging). Based on 6,000 pitfall trap-days and 60,000 m of visual surveys, we recorded 215 individuals representing 15 species. Contrary to expectations, species richness and abundance were not explained by any of the variables considered, including matrix quality, proportion of forest cover, forest patch area and shape, age since isolation, arthropod biomass, canopy openness, litter volume, tree density, and fire history. However, the composition of persisting species was determined by the structural complexity of the adjacent matrix. The abundance of species that avoid direct sun exposure to regulate their body temperature increased under more-complex structures of adjacent matrix areas and decreased within patches more intensively affected by past fire events. Disturbance within forest patches likely decreased the patch-matrix contrast, contributing to the absence of forest area effects. Nevertheless, species-specific microhabitat requirements dictated part of the lizard species that were able to persist in the fragmented landscape. Strategies aiming to maximize lizard diversity should embrace retention of the habitat quality within forest patches and forest corridors/high-stature vegetation in at least some sites connecting forest remnants.

Island biogeography theory and the urban landscape: stopover site selection by the silver-haired bat (Lasionycteris noctivagans)

Many migratory bats require forested sites for roosting and foraging along their migration path, but increased urbanization and intensive agricultural practices may reduce the availability of stopover sites. Urban forests may provide important stopover habitat, maintaining landscape connectivity in regions where the majority of natural habitat has been cleared for development. Island biogeography theory can be applied to urbanized temperate forest biomes where small urban forests represent islands separated from the larger “mainland” forest. We used acoustic monitoring during the fall migration period to investigate the use of urban forest habitat by a migratory species, the silver-haired bat (Lasionycteris noctivagans (Le Conte, 1831)). We predicted that recorded activity would have a positive relationship with forest patch area and shape and a negative relationship with isolation from other forest patches, as suggested by island biogeography theory. We observed greater activity at larger forest patches, and although relationships for shape and isolation were not statistically supported, the observed patterns were consistent with predictions. Our results demonstrate the need for more in-depth research on the habitat requirements for both migratory and resident bat species and the impact that ongoing urbanization has on local bat populations.

Multi-taxa ecological responses to habitat loss and fragmentation in western Amazonia as revealed by RAPELD biodiversity surveys

ABSTRACT Habitat loss and fragmentation caused by deforestation are important anthropogenic drivers of changes in biodiversity in the Amazon rainforest, and has reached its highest rate in recent decades. However, the magnitude and direction of the effects on species composition and distribution have yet to be fully understood. We evaluated the responses of four taxonomic groups − birds, amphibians, orchid bees, and dung beetles - to habitat loss and fragmentation at both species and assemblage level in the northern Ecuadorian Amazon. We sampled fifteen 250-m long plots in terra-firme forest remnants. We calculated one landscape fragmentation index (fragindex), which considers the proportion of continuous forest cover, edge density and isolation in the landscape, and nine landscape configuration metrics. Logistic regression models and multivariate regression trees were used to analyze species and assemblage responses. Our results revealed that over 80% of birds, amphibians or orchid-bee species, and 60% of dung beetles were negatively affected by habitat loss and fragmentation. Species composition of all taxonomic groups was significantly affected by differences in forest cover and connectivity. Less than 5% of all species were restricted to landscapes with fragindex values higher than 40%. Landscape metrics related to the shape and area of forest patches determined the magnitude and direction of the effect on species responses. Therefore, changes in the landscape configuration of Ecuadorian Amazonia should be minimized to diminish the effects of habitat loss and fragmentation on species occurrence and assemblage composition.

Landscape pattern optimization approach to protect rice terrace Agroecosystem: Case of GIAHS site Jiache Valley, Guizhou, southwest China

The rice terrace agroecosystems in mountainous regions occupy an important position in regional sustainable development and cultural diversity; some of them are included in the Globally Important Agricultural Heritage System (GIAHS). Despite the considerable progress made in protecting these unique agroecosystems, the research for planners to limit properly protected areas systematically, considering both their aesthetic and ecological values, is insufficient. In this study, an overall protecting framework was developed at the spatial planning level by optimizing the landscape pattern. We considered Jiache Valley, the core area of Congjiang’s Rice-Fish-Duck System rated in the GIAHS in 2011, as an example. Based on the indicators of visual sensitivity and ecological stability, we determined the protection scope of the core terrace area and performed a morphological spatial pattern analysis (MSPA) to identify the core area of forest patches and corridor buffer zones. Then, an ecological network corridor was constructed with the minimum cumulative resistance model; finally, the landscape optimization pattern of Jiache Valley was determined. The proposed plan not only highlights the terrace patches individually, but it also systematically protects the components of the agroecosystem including water, forests, and fields, thereby making them sustainable and exert overall ecological effects. By optimizing the patches of different spatial types and developing land management strategies within variable protection levels, the sustainable development of Jiache Valley could be promoted. The method has high significance in the optimization of landscape planning and management of rice terrace agroecosystems; it can also serve as a reference for other types of agroecosystems.

Human Activity and Forest Degradation Threaten Populations of the Nigeria\u2013Cameroon Chimpanzee (Pan troglodytes ellioti) in Western Cameroon

Increased human activities such as commodity-led deforestation, extension of agriculture, urbanization, and wildfires are major drivers of forest loss worldwide. In Cameroon, these activities cause a loss of suitable primate habitat and could ultimately threaten the survival of chimpanzees (Pan troglodytes). We derived independent estimates of the population size of the Endangered Nigeria–Cameroon chimpanzee (Pan troglodytes ellioti) in Kom-Wum Forest Reserve, Cameroon, and surrounding unprotected forest areas through 1) direct observations, 2) camera trapping, 3) distance sampling, 4) marked nest counts, and 5) standing crop nest counts. In addition, we georeferenced signs of chimpanzee and human activity along line transects. We used a generalized linear mixed model to predict the occurrence of chimpanzees in response to edge length (measured as the perimeter of core forest patches), core area of forest patches (measured as area of forest patches beyond an edge width of 100 m), habitat perforation (measured as the perimeter of nonforested landscape within core forest patches), patch size(measured as area of forest patches), and forest cover. Chimpanzee density estimates ranged from 0.1 (direct observation) to 0.9 (distance sampling) individuals km−2 depending on estimation method with a mean nest group size of 7 ± 5.4 (SD). The mean encounter rate for signs of chimpanzee activity was significantly higher in mature forests (2.3 signs km−1) than in secondary forests (0.3 signs km−1) and above 1000 m elevation (4.0 signs km−1) than below 1000 m (1.0 signs km−1). The mean encounter rate for signs of human activity was significantly higher in secondary (8.0 signs km−1) than in mature forests (0.9 signs km−1). Secondary forests, habitat perforation, and edge length had a significant negative effect on the occurrence of chimpanzee signs. Overall, human activity and forest degradation affected the number of observed chimpanzee signs negatively. Regular antipoaching patrols and reforestation programs in degraded areas could potentially reduce threats to populations of endangered species and may increase suitable habitat area.

Multi-Scale Ecological Connectivity Dynamics Associated With Hydropower Station: A Case Study in the Lancang River Valley

Dam construction is a major threat to terrestrial ecological processes that exhibit spatial variation. As an effective indicator of species movements at large scales, the dynamics of forest landscape connectivity for the dispersal abilities of local species such as primates both upstream and downstream of the Manwan hydropower station were compared in three periods: before, during, and after dam construction (in 1974, 1988, and 2004, respectively). The equivalent connected area (ECA) index which was modified from the probability of connectivity (PC) index based on the graph theory was applied in this study. We used this method to analyze the spatial and temporal changes in the overall forest landscape connectivity due to dam construction. The results showed that forest connectivity decreased after dam construction. The forest connectivity upstream was much greater than that downstream in 1974 but was lower in 1988 and 2004. The importance of connectivity increased with increasing dispersal distance. Only 8, 12, and 18% of forest patches of small area exhibited changes in 1974, 1988, and 2004, respectively. Most of the large habitat patches (i.e., those with dECA values &amp;gt;50%) remained stable, and the greatest patch changes were found at a dispersal distance of 400 m in all three periods. These large forest patch changes often occurred near the boundary of the study area. The Betweenness Centrality indicator, which identifies patches as stepping stones while accounting for ecological processes and biological flows at a larger scale, indicated that some habitat patches near Manwan Dam acted as stepping stones in maintaining the forest connectivity. Furthermore, rank correlations between the forest patch area and the three dPC (intra, flux, connector) fractions indicated that the dPCflux indicator can be used to measure the prioritization of habitat patches.

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.

Elephants in the neighborhood: patterns of crop-raiding by Asian elephants within a fragmented landscape of Eastern India.

Loss of forest cover, rise in human populations and fragmentation of habitats leads to decline in biodiversity and extinction of large mammals globally. Elephants, being the largest of terrestrial mammals, symbolize global conservation programs and co-occur with humans within multiple-use landscapes of Asia and Africa. Within such shared landscapes, poaching, habitat loss and extent of human–elephant conflicts (HEC) affect survival and conservation of elephants. HEC are severe in South Asia with increasing attacks on humans, crop depredation and property damage. Such incidents reduce societal tolerance towards elephants and increase the risk of retaliation by local communities. We analyzed a 2-year dataset on crop depredation by Asian elephants (N = 380) events in North Bengal (eastern India). We also explored the effect of landscape, anthropogenic factors (area of forest, agriculture, distance to protected area, area of human settlements, riverine patches and human density) on the spatial occurrence of such incidents.Crop depredation showed a distinct nocturnal pattern (22.00–06:00) and majority of the incidents were recorded in the monsoon and post-monsoon seasons. Results of our spatial analysis suggest that crop depredation increased with an increase in the area of forest patches, agriculture, presence of riverine patches and human density. Probability of crop depredation further increased with decreasing distance from protected areas. Villages within 1.5 km of a forest patch were most affected. Crop raiding incidents suggest a deviation from the “high-risk high-gain male biased” foraging behavior and involved proportionately more mixed groups (57%) than lone bulls (43%). Demographic data suggest that mixed groups comprised an average of 23 individuals with adult and sub adult females, bulls and calves. Crop depredation and fatal elephant attacks on humans were spatially clustered with eastern, central and western parts of North Bengal identified as hotspots of HEC. Our results will help to prioritize mitigation measures such as prohibition of alcohol production within villages, improving condition of riverine patches, changing crop composition, fencing agriculture fields, implement early warning systems around protected areas and training local people on how to prevent conflicts.