continuous forest
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2022 ◽  
Vol 14 (2) ◽  
pp. 364
Author(s):  
Zhilong Xi ◽  
Huadong Xu ◽  
Yanqiu Xing ◽  
Weishu Gong ◽  
Guizhen Chen ◽  
...  

Spaceborne LiDAR has been widely used to obtain forest canopy heights over large areas, but it is still a challenge to obtain spatio-continuous forest canopy heights with this technology. In order to make up for this deficiency and take advantage of the complementary for multi-source remote sensing data in forest canopy height mapping, a new method to estimate forest canopy height was proposed by synergizing the spaceborne LiDAR (ICESat-2) data, Synthetic Aperture Radar (SAR) data, multi-spectral images, and topographic data considering forest types. In this study, National Geographical Condition Monitoring (NGCM) data was used to extract the distributions of coniferous forest (CF), broadleaf forest (BF), and mixed forest (MF) in Hua’ nan forest area in Heilongjiang Province, China. Accordingly, the forest canopy height estimation models for whole forest (all forests together without distinguishing types, WF), CF, BF, and MF were established, respectively, by Radom Forest (RF) and Gradient Boosting Decision Tree (GBDT). The accuracy for established models and the forest canopy height obtained based on estimation models were validated consequently. The results showed that the forest canopy height estimation models considering forest types had better performance than the model grouping all types of forest together. Compared with GBDT, RF with optimal variables had better performance in forest canopy height estimation with Pearson’s correlation coefficient (R) and the root-mean-squared error (RMSE) values for CF, BF, and MF of 0.72, 0.59, 0.62, and 3.15, 3.37, 3.26 m, respectively. It has been validated that a synergy of ICESat-2 with other remote sensing data can make a crucial contribution to spatio-continuous forest canopy height mapping, especially for areas covered by different types of forest.


2021 ◽  
Vol 9 ◽  
Author(s):  
Erika de la Peña-Cuéllar ◽  
Julieta Benítez-Malvido

Some animal species exhibit sex-specific patterns as an adaptation to their habitats, however, adaptability to a human-dominated landscape is commonly explored without considering intraspecific sexual differences. Differences between males and females lead to a sexual segregation in habitat use. In southern Mexico, we explored sex-specific responses to landscape modification of six common species of phyllostomid bats: Artibeus jamaicensis, A. lituratus, Sturnira lilium, Carollia perspicillata, Glossophaga soricina, and Platyrrhinus helleri using riparian corridors within continuous forest and cattle pastures. Furthermore, we explored sex related responses to vegetation attributes (i.e., tree height and basal area) and seasonality (i.e., wet and dry seasons). Overall, capture rates were significantly skewed toward females and riparian corridors in pastures. Females of G. soricina exhibited a strong positive relationship with greater tree height and basal area. Seasonality was important for A. lituratus and S. lilium females, only. The results indicate a sexual driven response of bats to habitat modification. The high energetic demands of females associated to reproduction could lead to foraging into riparian corridors in pastures. The presence of large trees along riparian corridors in pastures may help maintaining a diverse and dynamic bat community in modified tropical landscapes.


2021 ◽  
Vol 4 ◽  
Author(s):  
George C. Gaines ◽  
David L. R. Affleck

Wildfire activity in the western United States is expanding and many western forests are struggling to regenerate postfire. Accurate estimates of forest regeneration following wildfire are critical for postfire forest management planning and monitoring forest dynamics. National or regional forest inventory programs can provide vegetation data for direct spatiotemporal domain estimation of postfire tree density, but samples within domains of administrative utility may be small (or empty). Indirect domain expansion estimators, which borrow extra-domain sample data to increase precision of domain estimates, offer a possible alternative. This research evaluates domain sample sizes and direct estimates in domains spanning large geographic extents and ranging from 1 to 10 years in temporal scope. In aggregate, domain sample sizes prove too small and standard errors of direct estimates too high. We subsequently compare two indirect estimators—one generated by averaging over observations that are proximate in space, the other by averaging over observations that are proximate in time—on the basis of estimated standard error. We also present a new estimator of the mean squared error (MSE) of indirect domain estimators which accounts for covariance between direct and indirect domain estimates. Borrowing sample data from within the geographic extents of our domains, but from an expanded set of measurement years, proves to be the superior strategy for augmenting domain sample sizes to reduce domain standard errors in this application. However, MSE estimates prove too frequently negative and highly variable for operational utility in this context, even when averaged over multiple proximate domains.


2021 ◽  
Author(s):  
Maria Juliana Bedoya ◽  
Harrison H Jones ◽  
Kristen Malone ◽  
Lyn C Branch

Abstract Context: Shade coffee plantations are purported to maintain forest biodiversity in agricultural landscapes. Understanding their conservation importance is hindered, however, by the limited taxa studied and failure to account for the landscape context of plantations and quality of reference sites.Objectives/Research questions: (1) how occupancy of mammals and birds changed from continuous forest to fragmented forest and coffee plantations while statistically controlling for landscape context, and (2) whether mammal and bird communities responded differently to shade coffee with regard to richness and composition.Methods: We used camera traps to sample ground-dwelling birds and medium- and large-bodied mammals (31 and 29 species, respectively) in shade coffee plantations and two types of reference forest (fragmented and continuous) in Colombia’s Western Andes. We used a multi-species occupancy model to correct for detection and to estimate occupancy, richness, and community composition.Results Shade coffee lacked ~50% of the species found in continuous forest, primarily forest-specialist insectivorous birds and forest-specialist and large-bodied mammals, resulting in different species composition between coffee and forest assemblages. Coffee plantation birds were generally a unique subset of disturbance-adapted specialists, whereas mammals in coffee were mostly generalists encountered across land uses. Forest fragments had species richness more similar to shade coffee than to continuous forest. Species sensitive to shade coffee responded negatively to isolation and disturbance at the landscape scale.Conclusions: Studies comparing coffee with relictual forest fragments may overestimate the conservation value of shade coffee. Conservation of biodiversity in shade coffee landscapes will be ineffective unless these efforts are linked to larger landscape-level conservation initiatives.


Author(s):  
Victor Carcarra-Bes ◽  
Matteo Pardini ◽  
Changhyun Choi ◽  
Roman Guliaev ◽  
Konstantinos P. Papathanassiou

2021 ◽  
Author(s):  
Eric R Scott ◽  
Emilio Miguel Bruna ◽  
María Uriarte

Deforestation often results in landscapes where remaining forest habitat is highly fragmented, with remnants of different sizes embedded in an often highly contrasting matrix. Local extinction of species from individual fragments is common, but the demographic mechanisms underlying these extinctions are poorly understood. It is often hypothesized that altered environmental conditions in fragments drive declines in reproduction, recruitment, or survivorship. The Amazon basin, in addition to experiencing continuing fragmentation, is warming and experiencing changes in precipitation leading to altered frequency and intensity of droughts and unusually wet periods. Whether plant populations in tropical forest fragments are particularly susceptible to extremes in precipitation remains unclear. Most studies of plants in fragments are relatively short (1-6 years), focus on a single life-history stage, and often do not compare to populations in continuous forest. Even fewer studies consider delayed effects of climate on demographic vital rates despite the importance of delayed effects in studies that consider them. Using a decade of demographic and climate data from an experimentally fragmented landscape in the Central Amazon, we assess the effects of climate on populations of an understory herb (Heliconia acuminata, Heliconiaceae). We used distributed lag non-linear models to understand the delayed effects of temperature and precipitation on survival, growth, and flowering. We detected delayed effects of climate up to 36 months. Drought two dry seasons prior to the February census decreased survival and increased flowering probability while drought in the wet season a year prior to the census decreased flowering probability and increased growth. The effects of extremes in precipitation on survival and growth were more pronounced in forest fragments compared to continuous forest. The complex delayed effects of climate and habitat fragmentation in our study point to the importance of long-term demography experiments in understanding the effects of anthropogenic change on plant populations.


Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 277
Author(s):  
Jakub Gryz ◽  
Tomasz Jaworski ◽  
Dagny Krauze-Gryz

The red squirrel typically nests in dreys and tree hollows, but also (when given an opportunity) in large nest boxes. We assessed the occupancy rate of nest boxes by red squirrel and non-target species (120 boxes in the continuous forest, habitat mosaic and urban park, checked annually for eight years). Habitat type explained the variability in the occupancy of nest boxes by different species/taxa. Red squirrels used nest boxes in all habitats but occupancy rates were highest in the urban park (>50% of the boxes at maximum) and lowest in the forest. This could be explained by high population density, competition for shelters and willingness to explore alternative sheltering opportunities by urban squirrels. The yellow-necked mouse inhabited nest boxes infrequently and mostly in habitat mosaic. Tits mostly occurred in the forest and least often in the park, which suggests limited availability of natural cavities in managed forest. Nest box occupancy by starlings increased with an anthropopression level, which reflects high densities of urban and rural populations of the species. Hymenoptera (mainly wasps) were present only in rural areas, which may be due to their persecution by humans or use of anti-mosquito pesticides in urban parks. Additionally, 24 insect species were found to inhabit squirrel dreys.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Camilo A. Calderón-Acevedo ◽  
Armando Rodríguez-Durán ◽  
J. Angel Soto-Centeno

AbstractUrbanization and natural disasters can disrupt landscape connectivity, effectively isolating populations and increasing the risk of local extirpation particularly in island systems. To understand how fragmentation affects corridors among forested areas, we used circuit theory to model the landscape connectivity of the endemic bat Stenoderma rufum within Puerto Rico. Our models combined species occurrences, land use, habitat suitability, and vegetation cover data that were used either as resistance (land use) or conductance layers (habitat suitability and vegetation cover). Urbanization affected connectivity overall from east to west and underscored protected and rustic areas for the maintenance of forest corridors. Suitable habitat provided a reliable measure of connectivity among potential movement corridors that connected more isolated areas. We found that intense hurricanes that disrupt forest integrity can affect connectivity of suitable habitat. Some of the largest protected areas in the east of Puerto Rico are at an increasing risk of becoming disconnected from more continuous forest patches. Given the increasing rate of urbanization, this pattern could also apply to other vertebrates. Our findings show the importance of maintaining forest integrity, emphasizing the considerable conservation value of rustic areas for the preservation of local biodiversity.


Sociobiology ◽  
2021 ◽  
Vol 68 (1) ◽  
pp. 5861
Author(s):  
Ana Isabel Sobreiro ◽  
Lucas Lopes da Silveira Peres ◽  
Jessica Amaral Henrique ◽  
Rosilda Mara Mussury ◽  
Valter Vieira Alves-Junior

Forest habitats are important sources of food and nesting resources for pollinators, primarily in urban areas and landscapes with intense agricultural activity. The forest fragmentation and environmental changes occurring in these green refuges are known to impose survival challenges to pollinating bees, leading to species loss. However, it is not well known how the species of bees that visit flowers are distributed in forest micro-environments. To fill this gap, we sampled flower visiting bees in a continuous forest matrix with micro-environments of two forest types (mature and regenerating forest). We examined how the local environmental changes and climatic conditions affect the composition and uniformity of bee communities in the different micro-environments. Our results indicated that both abundance and richness were similar between forest types studied here, however climatic conditions and plant flowering patterns affect the composition of bees. Thus, our results demonstrated that the continuous micro-environments can favor floral visits and the reintegration of bee communities, and still, that this strategy can be used to minimize the impacts of environmental changes at local scales.


2021 ◽  
Vol 14 ◽  
pp. 194008292110173
Author(s):  
Ana Filipa Palmeirim ◽  
Rafael de Fraga ◽  
Marcus V. Vieira ◽  
Carlos A. Peres

Neotropical snakes have extremely low detection rates, hampering our understanding of their responses to habitat loss and fragmentation. We addressed this gap using a limited sample (50 individuals, 16 species) across 25 variable-size insular forest fragments within a hydroelectric lake and four adjacent mainland continuous forest sites, in Central Brazilian Amazonia. The number of species recorded on forest islands (1.55 [Formula: see text] 0.78) was much lower than that at continuous forest sites (5.0 [Formula: see text] 3.1), with no snakes being recorded at twelve islands smaller than 30 ha. As such, snake assemblages were positively affected by forest area, explaining 48% of the number of species, and negatively affected by island isolation. The markedly higher number of species recorded across continuous forest sites likely results from the availability of riparian habitats, which have virtually disappeared from the archipelagic landscape given the widespread inundation of lowland areas. To prevent further severe biodiversity loss, including those of poorly known rare taxa, conservation policies should avert the additional construction of mega-dams that create myriad of small islands, in addition to extensive reservoir lakes from which all riparian habitats are eliminated.


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