scholarly journals Heterogenization of remaining biodiversity in fragmented tropical forests across agricultural landscapes

2019 ◽  
Author(s):  
Cristina Yuri Vidal ◽  
Diogo Souza Bezerra Rocha ◽  
Marinez Ferreira de Siqueira ◽  
Ricardo Ribeiro Rodrigues ◽  
Tadeu Siqueira

AbstractThe increasing worldwide interest on the conservation of tropical forests reflects the conversion of over 50% of their area into agricultural lands and other uses. Understanding the distribution of remaining biodiversity across agricultural landscapes is an essential task to guide future conservation strategies. To understand the long-term effects of fragmentation on biodiversity, we investigated whether forest fragments in southeastern Brazil are under a taxonomic homogenization or heterogenization process. We estimated pre-deforestation species richness and composition based on a Species Distribution Modelling approach, and compared them to the observed patterns of α- and β-diversity. In particular, we asked (i) if changes in β-diversity reveal convergence or divergence on species composition; (ii) if these changes are similar between forest fragments in Strictly Protected Areas (SPAs) (n=20) and within private lands (n=367) and in different regions of the state (West, Center, and Southeast). We detected steep reductions in observed local species richness in relation to our modeled predictions, and this was particularly true among forest fragments in non-protected private lands. The higher observed β diversity indicated an overall biotic heterogenization process, consistent with the idea that the originally diverse vegetation is now reduced to small and isolated patches, with unique disturbance histories and impoverished communities derived from a large regional species pool. Since conservation of biodiversity extends beyond the boundaries of strictly Protected Areas, we advocate forest fragments are valuable for conservation in agricultural landscapes, with particular relevance for private lands, which represent the most exposed and neglected share of what is left.

2018 ◽  
Vol 18 (2) ◽  
Author(s):  
Alex Augusto de Abreu Bovo ◽  
Marcelo Magioli ◽  
Alexandre Reis Percequillo ◽  
Cecilia Kruszynski ◽  
Vinicius Alberici ◽  
...  

Abstract: Human-modified landscapes (HMLs) are composed by small, isolated and defaunated forest fragments, which are surrounded by agricultural and urban areas. Information on species that thrives in these HMLs is essential to direct conservation strategies in local and regional scales. Since HMLs are dominant in the Atlantic Forest, we aimed to assess the mammalian diversity in a HML in southeastern Brazil and to propose conservation strategies. We collected data of terrestrial (small-, medium- and large-sized) and volant mammals in three small forest fragments (10, 14 and 26 ha) and adjacent areas, between 2003 and 2016, using complementary methods: active search, camera trapping, live-traps, mist nets and occasional records (i.e., roadkills). In addition, we used secondary data to complement our species list. We recorded 35 native mammal species (6 small-sized, 16 medium- and large-sized, and 13 bats) and seven exotic species in the HML. The recorded mammal assemblage (non-volant and volant), although mainly composed of common and generalist species, includes three medium- and large-sized species nationally threatened (Leopardus guttulus, Puma concolor and Puma yagouaroundi) and two data deficient species (Galictis cuja and Histiotus velatus), highlighting the importance of this HML for the maintenance and conservation of mammal populations. Despite highly impacted by anthropogenic disturbances, the study area harbors a significant richness of medium- and large-sized mammals, being an important biodiversity refuge in the region. However, this biodiversity is threatened by the low quality of the habitats, roadkills and abundant populations of domestic cats and dogs. Therefore, we stress the need of conservation strategies focusing on the medium- and large-sized mammals as an umbrella group, which could benefit all biodiversity in the landscape. We recommend actions that promotes biological restoration, aiming to increase structural composition and connectivity of the forest fragments, reducing roadkills and controlling the domestic cats and dogs' populations, in order to maintain and improve the diversity of mammals in long-term.


Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1984
Author(s):  
Anthi Oikonomou ◽  
Konstantinos Stefanidis

Disentangling the main drivers of species richness and community composition is a central theme in ecology. Freshwater biodiversity patterns have been poorly explored; yet, it has been shown that different freshwater biota have different, often contrasting responses to environmental gradients. In this study, we investigated the relative contribution of geographical and environmental (habitat-, climate- and water quality-related) factors/gradients in shaping the α- and β-diversity patterns of macrophytes and fish in sixteen natural freshwater lakes of an unexplored Balkan biodiversity hotspot, the Southern Balkan Peninsula. We employed generalized linear modeling to identify drivers of α-diversity, and generalized dissimilarity modeling to explore commonalities and dissimilarities of among-biota β-diversity. Species richness of both biota was significantly associated with lake surface area, whereas macrophytes had an inverse response to altitude, compared to fish. Both species turnover and nestedness significantly contributed to the total β-diversity of macrophytes. In contrast, species turnover was the most significant contributor to the total fish β-diversity. We found that the compositional variation of macrophytes is primarily limited by dispersal and ultimately shaped by environmental drivers, resulting in spatially structured assemblages. Fish communities were primarily shaped by altitude, highlighting the role of species sorting. We conclude that among-biota diversity patterns are shaped by different/contrasting factors, and, thus, effective/sustainable conservation strategies should encompass multiple aquatic biota.


The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 585-594 ◽  
Author(s):  
Marcos Maldonado-Coelho ◽  
Miguel  Marini

Abstract We analyzed patterns of species richness, size, structure, and composition of mixed-species flocks in relation to forest fragment size and forest successional stage during dry and rainy seasons, at the state of Minas Gerais, southeastern Brazil. Three forest fragments (1.7, 50, and 200 ha) were used for fragment size analysis, and two fragments (200 and 300 ha) were used for successional stage analysis. Fragment size and season affected flock richness, size, stability, and composition. In the 1.7-ha fragment, flock species richness, size, and stability were significantly different only during the rainy season. Fragment successional stage also influenced flock richness and size, although season did not. Flock composition also had changes related to fragment successional stage. Fragment geometry seems to be an important factor influencing flock structure and composition.


2020 ◽  
Vol 4 (2) ◽  
pp. 91
Author(s):  
Erich De Freitas Mariano ◽  
Arnaldo Honorato Vieira-Filho ◽  
Gustavo Alves Toledo Da Costa ◽  
Helder Farias Pereira De Araujo ◽  
Malva Isabel Medina Hernandez

Fragmentation is one of environmental degradation and reduction of biodiversity causes, including in bird communities, mainly in Atlantic Forest areas. The aim of this study was to evaluate the differences in richness and functional groups structure in the ornitofauna from a Restinga forest fragment and four areas with different ages of reforestation. We selected five forest fragments in a Restinga area in the state of Paraiba. A native fragment (Control Area-AC) and four fragments that have undergone a mining process and present different ages of reforestation (1989, 1997, 2001 and 2003). The avifauna samples occurred in four expeditions between November 2006 and April 2008 and counted with a total effort of 2700 net.m2 per expedition. Statistical tests verified richness differences between studied areas, as well as the composition of their functional groups. In general, 90 bird species were recorded, and the highest reforestation age area presented the highest richness (n = 51 spp.). The species richness comparisons indicated that the difference in the richness between AC and reforested areas is not statistically significant. The similarity analysis indicates that reforested areas share a large amount of species and AC has a great differentiation in composition. This differentiation is explained by the significant presence of frugivorous, nectarivorous, leaf and understory-insectivorous species. Changes in species richness and composition in degraded areas are expected and reforested areas usually have a smaller number of forest-dependent species due to the deficiency of available resources. The recovery of areas by reforestation are important conservation strategies, however there is need for management measures that promote the enrichment of these areas and the availability of resources for species dependent on environments Forest.


2021 ◽  
Author(s):  
Marina Pannunzio Ribeiro ◽  
Kaline de Mello ◽  
Roberta Averna Valente

Abstract The highly modified urban matrix becomes an inhospitable environment for many species because the natural vegetation fragments are highly fragmented and often isolated in the landscape. Protected Areas (PAs) located closer or within urban areas may not achieve their goal of protecting local or regional biodiversity. Thus, the proposition of ecological corridors aims to connect the PAs, providing the dispersion of species in anthropogenic landscapes. In this context, this study aimed to evaluate the PAs connectivity in an urban landscape and understand if urban forest fragments can support their connectivity, generating important information for biodiversity conservation and urban planning. For this, we used models based on Graph Theory to assess the functional connectivity among PAs. The focal species used were Atlantic Forest birds. We used the participatory technique to assess their dispersal capabilities, and this information was used to create a resistance surface map. The focal species movement in the landscape was modeled through Graph Theory. This model evaluated the functional connectivity and extracted the least-cost paths between PAs and other forest fragments that designed the urban ecological network. We identified that few PAs are connected in the urban landscape of Sorocaba city and its surroundings and 28 forest fragments that are important to support the connectivity among PAs. Among these, only four fragments are located within a PA. The other 24 forest fragments located outside PAs should be the center of attention for forest conservation and restoration actions, as they can improve the connectivity between the PAs. Our results show that PAs connectivity in urban landscapes depends on incentives for native vegetation conservation on private lands once most of the important forest fragments for the PAs connectivity are located in these areas. In addition, the restoration of riparian zones is important because they compose a great ecological corridor in the urban landscape. Strategies that increase the permeability of the matrix (e.g., increasing green spaces and gardens) and restoring target fragments are also important. Finally, land-use planning, focusing on natural ecosystem conservation and combating urban sprawl, is necessary to promote PAs connectivity in urban landscapes.


PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255082
Author(s):  
Avantika Thapa ◽  
Pujan Kumar Pradhan ◽  
Bheem Dutt Joshi ◽  
Tanoy Mukherjee ◽  
Mukesh Thakur ◽  
...  

The present study aims to explore the mammalian diversity of Darjeeling district using camera traps along with questionnaire survey in protected area (PA) and non- protected area (Non-PA). We also attempted to understand the influence of habitat variables on mammalian species richness using the generalized linear mixed models (GLMM). A total of 30 mammal species were recorded of which 21 species were detected through camera trapping with the most abundant records of barking deer (Muntiacus muntjak) and least of the elusive Chinese pangolin (Manis pentadactyla) and red panda (Ailurus fulgens). Additionally, melanistic forms of four mammals were also recorded. The mammalian species richness, their capture rate and naïve occupancy did not differ significantly among the PA and Non-PA. The GLMM revealed that the proportions of oak and bamboo in the forest, percentage canopy cover and camera trap operational days (wAICc = 0.145, wBIC = 0.603) were significant predictors of species richness in the study. We suggest Non-PA forest of Darjeeling should be given equal conservation importance as to the PA. Landscape based conservation planning will be imperative for achieving long term conservation goals in the study area.


2019 ◽  
Vol 14 (4) ◽  
pp. 489-498
Author(s):  
Felipe Donateli Gatti ◽  
Marco Antonio Alves Carneiro

Species are elementary units in community ecology studies. However, sample limitations obstruct the elaboration of accurate faunistic inventories, especially in biodiversity hotspots, such as tropical forests. In this way, the objective of this research was to describe the richness, using different non-parametric estimators of richness, in the family Cerambycidade, a group of hyperdiverse insects in the Atlantic Forest. Five hundred and eighty-one specimens belonging to 145 species and 3 subfamilies were collected. Among the species sampled, 46.2% were considered singletons, 13.8% doubletons, 48.95% unicates, 15.15% duplicates and 90.3% ecologically rare. The species accumulation curves did not stabilize, which was already expected considering that more species and individuals were sampled in the last months of collection. The estimated richness presented values much higher than the observed richness. This was a reflect of the high proportion of ecologically rare species present in the sample. This work showed that faunistic inventories of hyperdiverse groups, with only one year of collection and a single sampling methodology may underestimate the species richness of a region. Thus, larger time series associated with different collection methods are essential for a more accurate survey of biodiversity in the Atlantic Forest.


2013 ◽  
Vol 368 (1619) ◽  
pp. 20120160 ◽  
Author(s):  
Claudia M. Stickler ◽  
Daniel C. Nepstad ◽  
Andrea A. Azevedo ◽  
David G. McGrath

Land-use regulations are a critical component of forest governance and conservation strategies, but their effectiveness in shaping landholder behaviour is poorly understood. We conducted a spatial and temporal analysis of the Brazilian Forest Code (BFC) to understand the patterns of regulatory compliance over time and across changes in the policy, and the implications of these compliance patterns for the perceived costs to landholders and environmental performance of agricultural landscapes in the southern Amazon state of Mato Grosso. Landholdings tended to remain in compliance or not according to their status at the beginning of the study period. The perceived economic burden of BFC compliance on soya bean and beef producers (US$3–5.6 billion in net present value of the land) may in part explain the massive, successful campaign launched by the farm lobby to change the BFC. The ecological benefits of compliance (e.g. greater connectivity and carbon) with the BFC are diffuse and do not compete effectively with the economic benefits of non-compliance that are perceived by landholders. Volatile regulation of land-use decisions that affect billions in economic rent that could be captured is an inadequate forest governance instrument; effectiveness of such regulations may increase when implemented in tandem with positive incentives for forest conservation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Subzar Ahmad Nanda ◽  
Manzoor-ul Haq ◽  
S. P. Singh ◽  
Zafar A. Reshi ◽  
Ranbeer S. Rawal ◽  
...  

AbstractUnderstanding the species richness and β-diversity patterns along elevation gradients can aid in formulating effective conservation strategies particularly in areas where local anthropogenic stresses and climate change are quite significant as in the Himalaya. Thus, we studied macrolichen richness and β-diversity along elevational gradients at three sites, namely Kashmir (2200 to 3800 m a.m.s.l), Uttarakhand (2000–3700 m a.m.s.l) and Sikkim (1700 to 4000 m a.m.s.l) which cover much of the Indian Himalayan Arc. In all, 245 macrolichen species belonging to 77 genera and 26 families were collected from the three sites. Only 11 species, 20 genera and 11 families were common among the three transects. Despite the differences in species composition, the dominant functional groups in the three sites were the same: foliose, fruticose and corticolous forms. The hump-shaped elevation pattern in species richness was exhibited by most of the lichen groups, though an inverse hump-shaped pattern was also observed in certain cases. β-diversity (βsor) based on all pairs of comparisons along an elevation gradient varied from 0.48 to 0.58 in Kashmir, 0.03 to 0.63 in Uttarakhand and 0.46 to 0.77 in Sikkim. The contribution of turnover to β-diversity was more than nestedness at all the three transects. Along elevation β-diversity and its components of turnover and nestedness varied significantly with elevation. While species turnover increased significantly along the elevation in all the three transects, nestedness decreased significantly in Kashmir and Sikkim transects but increased significantly in the Uttarakhand transect. Except for the Kashmir Himalayan elevation transect, stepwise β-diversity and its components of turnover and nestedness did not vary significantly with elevation. The present study, the first of its kind in the Himalayan region, clearly brings out that macrolichen species richness, β-diversity, and its components of turnover and nestedness vary along the elevation gradients across the Himalayan Arc. It also highlights that contribution of turnover to β-diversity is higher in comparison to nestedness at all the three transects. The variations in species richness and diversity along elevation gradients underpin the importance of considering elevational gradients in planning conservation strategies.


2021 ◽  
Vol 4 ◽  
Author(s):  
Marc Ancrenaz ◽  
Felicity Oram ◽  
Nardiyono Nardiyono ◽  
Muhammad Silmi ◽  
Marcie E. M. Jopony ◽  
...  

Historically, orangutans (Pongo spp.) lived in large contiguous areas of intact rainforest. Today, they are also found in highly modified and fragmented landscapes dominated by oil palm or industrial timber plantations; a situation that calls for new conservation approaches. Here we report signs of orangutan presence in more than 120 small forest fragments of <500 ha in size and isolated in extensive oil palm plantations across Borneo. We confirmed the long-term presence of adult resident females with dependent young in 42% of the fragments assessed by ground survey (n = 50), and the regular sightings of males traveling across the landscape. We argue that orangutans using and living in small isolated forest patches play an essential part in the metapopulation by maintaining gene flow among larger sub-populations distributed across multiple-use landscapes. In some cases, translocations may be necessary when the animals are in imminent danger of being killed and have no other refuge. However, the impacts of removing animals from spatially dispersed metapopulations could inadvertently decrease critical metapopulation functionality necessary for long-term viability. It is clear that orangutans need natural forest to survive. However, our findings show that forest fragments within agricultural landscapes can also complement conservation areas if they are well-distributed, properly connected and managed, and if orangutan killing is prevented. Efforts to better understand the dynamics and the functionality of an orangutan metapopulation in forest-farmland landscape mosaics characteristic of the Anthropocene are urgently needed to design more efficient conservation strategies for the species across its range.


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