Conservation Value Of Secondary Forests Research Articles

Seasonal home range utilization of Hainan gibbons (Nomascus hainanus) in a secondary tropical forest of Hainan Island, South China

The home range utilization of primates reflects their behavioral and ecological strategies to adapt to their environment. However, little is known about the home range behavior of endemic gibbons (Nomascus hainanus) found in a secondary tropical forest of Hainan Island, China. Knowledge of their ranging patterns could contribute to scientific evaluations of the survival risk of this species under habitat conversion. In this study, we analyzed the home range utilization patterns and the seasonal variation of a group of Hainan gibbons in secondary tropical forests in the Bawangling area of National Park of Hainan Tropical Rainforest, using infrared cameras and direct observations. The results show that the annual home area of the gibbon group was 137.4 ha, with no significant difference between the wet and dry seasons. The feeding hotspots of Hainan gibbons are more scattered in the rainy season and more concentrated in the dry season, but not for sleeping hotspots. The relatively small home range suggests that secondary forests may not represent low-quality habitats and thus have a supporting role for the Hainan gibbon population. The widely distributed range of feeding hotspots in the rainy season may be related to the abundance of fruit resources in this season, while gibbons reduce their travel distance and energy expenditure when food is scarce in the dry season. Overall, our findings provide insights into the ecological flexibility of gibbons to seasonal variations in food resources and highlight the conservation value of secondary forests for gibbon populations.

Trophic position determines the persistence of neotropical understory birds after forest disturbance.

Habitat loss and degradation are key drivers of the current biodiversity crisis. Most research focuses on the question of which traits allow species to persist in degraded habitats. We asked whether a species' trophic position or niche width influences the resilience of species in degraded habitats and to what extent habitat degradation affects trophic interactions between species. We used nitrogen isotope ratios (15N:14N, expressed as δ15N value) to quantify and compare trophic positions and niche widths of understory birds inhabiting old-growth and young secondary forests in the Pacific lowlands of Costa Rica. We found that a species' trophic position rather than its trophic niche width determined its persistence in secondary forests. Species feeding at lower trophic levels in old-growth forests were less likely to persist in secondary forests than those occupying a higher trophic position in old-growth forests. This pattern is likely induced by the occurrence of relatively large-bodied habitat specialists with a flexible and high-trophic level diet in secondary forests. These habitat specialists likely caused generalist bird species to lower their trophic position relative to conspecifics in old-growth forests. Regarding trophic niche widths, species in secondary forests tend to have larger niche widths than old-growth forest species. However, as old-growth forest specialists and generalists did not differ in their niche widths, no systematic effect of trophic niche width on species persistence after forest disturbance was found. This is the first study that shows a systematic effect of trophic position on the persistence of a wide range of bird species in a disturbed forest ecosystem. It therefore provides important insights into species' responses to habitat degradation and the conservation value of secondary forests. To improve habitat quality for old-growth forest birds and facilitate avian seed dispersal, the creation of large contiguous forest patches should be prioritised when implementing reforestation measures.

The importance of old secondary forests for understory birds in the tropical Andes

Deforestation is perhaps the greatest threat to tropical biodiversity. Anyway, extensive areas in the tropics have naturally regenerated and become secondary forests, which might mitigate biodiversity loss. However, evidence about the value of secondary forests for biodiversity conservation is still controversial. To establish the conservation value of secondary forests in the tropical Andes, we compared bird species richness, abundance, and composition between old and mature secondary forests using camera traps for two consecutive years. Our results suggest that old and mature secondary forests are similar in species richness and abundance to mature secondary forests, but these habitats significantly differ in species composition. Old secondary forests harbored some species highly specialized to mature forests (e.g., ant-following insectivorous birds: Myrmeciza longipes, Gymnopithys bicolor, Formicarius analis, and Dendrocincla fuliginosa) that are highly sensitive to habitat disturbance. Additionally, old secondary forests constitute suitable habitat for several species with decreasing populations, which could become of conservation importance in the long run. We consider that old secondary forests surrounded by mature forests can contribute to conserving understory birds, one of the most susceptible groups, negatively affected by tropical forest loss and degradation. Therefore, strategies for habitat biodiversity protection in this region should also include old secondary forests.

Sucessional trajetories of bird assemblages in amazonian secondary forests: Perspectives from complementary biodiversity dimensions

Secondary forests occupy extensive areas in tropical regions, providing an opportunity to investigate their relevance to biodiversity restoration. However, determining the conservation value of secondary forests and evaluating their successional trajectories depends on how biodiversity is measured. Here, we explore different biodiversity dimensions to understand how bird assemblages recover from forest disturbance caused by small scale farmers in the Amazon. We sampled bird species through standard visual and auditory censuses in 24 small plots of 1-hectare distributed in a paired design of old growth forests and secondary forests from different age categories (early, middle and late succession). We used 12 biodiversity metrics to explore the taxonomic, functional, and phylogenetic dimensions of bird diversity. Total species richness and evenness was similar between secondary and old growth forests. In contrast, the number of passerine species and disturbance-vulnerable species were higher in the controls of old growth forests compared to secondary forests. The relative abundance of birds with distinct functional traits consistently differed between the secondary forests of different age categories and their old growth forest counterparts. Functional evenness and divergence increased with canopy height and basal area through forest regeneration. In contrast, bird phylogenetic diversity in secondary forests was higher compared to those found in old growth forests while accounting for forest types and age categories of secondary forests. Bird species tolerant to disturbances partially compensate the loss of avian taxonomic and phylogenetic diversity during the conversion of undisturbed forests to agricultural fields. Changes in functional evenness and functional divergence suggest that resources used by birds are altered along the secondary succession and that the niche complementarity among species is reduced in more intensively managed sites. Ecological succession can be highly complex in terms of taxa identity, their functional roles and evolutionary history. Therefore, measurements that explore distinct biodiversity dimensions are fundamental to understanding how species are organized in assemblages across time and space.

Geometrid moth assemblages reflect high conservation value of naturally regenerated secondary forests in temperate China

The widespread destruction of mature forests in China has led to massive ecological degradation, counteracted in recent decades by substantial efforts to promote forest plantations and protect secondary forest ecosystems. The value of the resulting forests for biodiversity conservation is widely unknown, particularly in relation to highly diverse invertebrate taxa that fulfil important ecosystem services. We aimed to address this knowledge gap, establishing the conservation value of secondary forests on Dongling Mountain, North China based on the diversity of geometrid moths – a species-rich family of nocturnal pollinators that also influences plant assemblages through caterpillar herbivory. Results showed that secondary forests harboured geometrid moth assemblages similar in species richness and phylogenetic diversity, but with a species composition distinctly different to assemblages in one of China’s last remaining mature temperate forests in the Changbaishan Nature Reserve. Species overlap between these sites was about 30%, and species did not form separate phylogenetic clusters according to site. Species assemblages at Dongling Mountain were strongly differentiated according to forest type; a pattern not found at Changbaishan. Our results indicate that protected naturally regenerated secondary forests in northern China provide suitable habitats for species-rich and genetically diverse geometrid moth assemblages, highlighting the potential importance of these forests for conservation and ecosystem function provision across the wider landscape.

Quantifying carbon and amphibian co‐benefits from secondary forest regeneration in the Tropical Andes

AbstractTropical land‐use change is a key driver of global declines in biodiversity and a major source of anthropogenic carbon emissions, yet there is a substantial shortfall in the funding available to tackle these issues. We urgently need mechanisms that can simultaneously tackle both biodiversity and carbon losses, with carbon‐based payments for ecosystem services (e.g. REDD+) of particular interest. A critical question is whether such payments offer strong carbon–biodiversity co‐benefits via the regrowth of forests on abandoned farmlands (carbon enhancements) for amphibians, which are the most threatened vertebrate group and reach the greatest richness of threatened and small‐ranged species in the montane tropics (>1000 m a.s.l.). Here, we study changes in amphibian communities across a typical Andean habitat transition from cattle pasture through secondary forests (8–35 years) to primary forest. As secondary forests mature, they recovered the abundance, species richness, species composition and Red‐listed (near threatened and threatened) species typically found in primary forest. By contrast, cattle pasture contained much lower richness of Red‐listed species and a different species composition compared to forest. We then reveal positive relationships between carbon stocks and amphibian species richness and abundance, Red‐listed species richness and abundance and the similarity of communities to primary forests, confirming significant carbon–biodiversity co‐benefits. Our results underscore the high conservation value of secondary forests and the strong potential for carbon and biodiversity recovery. Using carbon‐based funding initiatives to support the regrowth of forests on marginal agricultural land is therefore likely to conserve threatened biodiversity in the Tropical Andes.

The conservation value of secondary forests in the southern Brazilian Mata Atlântica from a spider perspective

In many tropical areas of the world, pristine forests have become rare. Nevertheless, due to shifts in the human population the area covered by secondary forests is increasing. These forests may harbor a rich flora and fauna and are considered to be main refuges for species of primary forests. However, this issue is far from clear. To assess the conservation value of secondary forests in the Atlantic Forest of Brazil, we compared the diversity of spiders in differently aged secondary forests with old-growth forests. Within a larger project treating several invertebrate taxa, we sampled spiders using a standard protocol in 24 sites of three successional stages (5-8, 15-20, 30-50 years old) and old-growth forests (. 100 years untouched) in two nature reserves. We describe the diversity and structure of the assemblages using morphospecies and genera and analyze richness at the genus level. Generic richness and diversity showed no differences between successional stages; i.e., did not increase from the youngest to older forests, but guild diversity did increase. The youngest stage showed the highest variability in generic composition, and the turnover of genera and species was strong between the younger forests (5-20 years old) and forests older than 30 years. High alpha diversity, high turnover among sites and the lack of differences in richness between stages support the value of secondary forests for species conservation in the region studied.

Conservation value of secondary forest habitats for endemic birds, a perspective from two widely separated tropical ecosystems

Tropical secondary forests are increasingly widespread, but their potential for conserving endemic birds remains unclear. Previous studies report different results; however all have been restricted to geographically discreet locations. This is important as different ecosystems are influenced by different external factors, possibly influencing conservation potential. Here we use consistent survey methods to examine how endemic bird richness varies between primary and secondary forest habitats in two widely separated tropical ecosystems, providing a more global context for evaluating the conservation value of secondary forests. Research was completed in Lambusango Forest Reserve (LFR) on Buton Island, Sulawesi, and Cusuco National Park (CNP), a Honduran cloud forest reserve. Bird communities in both forests were surveyed using 50 m radius point counts. Vulnerability assessments based on ecological theory on avifaunal assemblages were then conducted, which suggested endemics in LFR to be more susceptible to disturbance than those in CNP. Contrary to the results from our vulnerability assessments, endemics in CNP were less tolerant of moderate habitat modification than those in LFR. Richness of Mesoamerican endemics per study site declined significantly between core zone forest (6.34 ± 0.81) and more degraded forest in the boundary zone (3.86 ± 0.69). Richness of Wallacean endemics was similar in primary (4.89 ± 1.68) and disturbed secondary forest (4.52 ± 1.62). We recommend considering local and regional biogeographical and ecological factors when determining the conservation value of secondary forests, and suggest examples of potential importance, including differential community richness, influence of figs and human settlement patterns.

Habitat structure and food resources for wildlife across successional stages in a tropical forest

Tropical forests are experiencing an increase in the proportion of secondary forests as a result of the balance between the widespread harvesting of old-growth forests and the regeneration in abandoned areas. The impacts of such a process on biodiversity are poorly known and intensely debated. Recent reviews and multi-taxa studies indicate that species replacement in wildlife assemblages is a consistent pattern, sometimes stronger than changes in diversity, with a replacement from habitat generalists to old-growth specialists being commonly observed during tropical forest regeneration. However, the ecological drivers of such compositional changes are rarely investigated, despite its importance in assessing the conservation value of secondary forests, and to support and guide management techniques for restoration. By sampling 28 sites in a continuous Atlantic forest area in Southeastern Brazil, we assessed how important aspects of habitat structure and food resources for wildlife change across successional stages, and point out hypotheses on the implications of these changes for wildlife recovery. Old-growth areas presented a more complex structure at ground level (deeper leaf litter, and higher woody debris volume) and higher fruit availability from an understorey palm, whereas vegetation connectivity, ground-dwelling arthropod biomass, and total fruit availability were higher in earlier successional stages. From these results we hypothetize that generalist species adapted to fast population growth in resource-rich environments should proliferate and dominate earlier successional stages, while species with higher competitive ability in resource-limited environments, or those that depend on resources such as palm fruits, on higher complexity at the ground level, or on open space for flying, should dominate older-growth forests. Since the identification of the drivers of wildlife recovery is crucial for restoration strategies, it is important that future work test and further develop the proposed hypotheses. We also found structural and functional differences between old-growth forests and secondary forests with more than 80years of regeneration, suggesting that restoration strategies may be crucial to recover structural and functional aspects expected to be important for wildlife in much altered ecosystems, such as the Brazilian Atlantic forest.

The Conservation Value of Secondary Forests for Vascular Epiphytes in Central Panama

AbstractSecondary forests that develop following land abandonment could compensate for the losses of diversity and structure that accompany deforestation of old‐growth forests in tropical regions. Whether secondary forests can harbor similar species richness, density, and composition of old‐growth forests for vascular epiphytes remains largely unknown for secondary forests older than 50 yr. We examined community structure (species richness, density, and species composition) of vascular epiphytes in older secondary forests between 35 and 115 yr after land abandonment and nearby old‐growth forests to determine if the community structure of epiphytes in secondary forests approaches that of old‐growth forests over time. The recovery of epiphyte species richness was rapid with 55‐year‐old forests containing 65 percent of old‐growth epiphyte species richness. Secondary forest epiphyte communities were found to be statistically nested within secondary forests older in age and within old‐growth forests. Similarity of epiphyte communities to old‐growth forests increased to 75 percent, 115 yr after abandonment. This study suggests that secondary forests will likely recover old‐growth epiphyte richness and composition given enough time. Epiphyte densities did not recover quickly with 55‐year‐old forests having 14 percent and 115‐year‐old forests having only 49 percent of the density of old‐growth forest epiphytes. The low density of epiphytes in secondary forests could impact rainforest diversity and function. We conclude that in less than 115 yr, although secondary moist forests have high conservation value for some aspects of community structure, they are unlikely to compensate biologically for the loss of diversity and ecosystem function that high epiphyte densities provide.

Traditional forest management has limited impact on plant diversity and composition in a tropical seasonal rainforest in SW China

In order to determine the impacts of different traditional forest management types on plant diversity of the seasonal tropical rainforests and infer effective conservation strategies, four types of forests with different management histories were studied in Nabanhe National Nature Reserve (NNNR), Xishuangbanna, China. They were: old-growth forest (non-timber product collection allowed), understorey planted old-growth forests, old secondary forests (∼200-years after slash and burn), and young secondary forest (15–50-years after slash and burn). Although human activities affected tree diversity and composition of the forests in NNNR, the forest regeneration potential of the different management systems were good. Even the young secondary forests, that showed the lowest Fisher’s alpha diversity at the plot level, had similar diversity levels to old-growth forest when all plots were combined. Number of red list tree species, timber species, and edible plant species in young secondary forests was as high as those of old-growth forests, and higher than old secondary forests. Additionally, there were a number of vulnerable and endangered species that were more common in the secondary than old-growth forests, indicating the high conservation value of secondary forests. Understorey plantation in old-growth forest, however, impaired regeneration of the climax species. The beneficial effects of traditional forest use depend strongly on its small scale and its close proximity to undisturbed forest, which serves as a species source during secondary forest regeneration. Unfortunately, traditional forest use is now under serious threat by expanding large-scale monoculture rubber plantations.

Mechanisms of faunal recovery during forest regeneration and the conservation value of secondary forests – Atlantic forest small mammals as a model

Mechanisms of faunal recovery during forest regeneration and the conservation value of secondary forests – Atlantic forest small mammals as a model

The conservation value of secondary forests for tropical nocturnal bird species

The conservation value of secondary forests for tropical nocturnal bird species

The Emerging Era of Novel Tropical Forests

ABSTRACTIn 1966 Eugene P. Odum delivered a speech before the Ecological Society of America that transformed the way ecologists looked at succession. His comparison of mature and successional systems lead ecologists to place secondary forests in an inferior position relative to mature ones to the point that today, prominent tropical biologists argue for and against the conservation value of secondary forests. Nevertheless, we live in the era of secondary forests that is rapidly giving way to a new era of novel tropical forests. Research in Puerto Rico documents the emergence of novel forests, which are different in terms of species composition, dominance, and relative importance of species from forests that were present before the island was deforested. These novel forests emerged without assistance. They are a natural response to the new environmental conditions created by human activity. Natural processes have remixed or reassembled native and introduced plant and animal species into novel communities adapted to anthropogenic environmental conditions. Novel forests are expected to protect soils, cycle nutrients, support wildlife, store carbon, maintain watershed functions, and mitigate species extinctions. The dawn of the age of tropical novel forests is upon us and must not be ignored.

Rapid Recovery of Biomass, Species Richness, and Species Composition in a Forest Chronosequence in Northeastern Costa Rica

ABSTRACTSecondary forests are a vital part of the tropical landscape, and their worldwide extent and importance continues to increase. Here, we present the largest chronosequence data set on forest succession in the wet tropics that includes both secondary and old‐growth sites. We performed 0.1 ha vegetation inventories in 30 sites in northeastern Costa Rica, including seven old‐growth forests and 23 secondary forests on former pastures, ranging from 10 to 42 yr. The secondary forest sites were formerly pasture for intervals of <1–25 yr. Aboveground biomass in secondary forests recovered rapidly, with sites already exhibiting values comparable to old growth after 21–30 yr, and biomass accumulation was not impacted by the length of time that a site was in pasture. Species richness reached old‐growth levels in as little as 30 yr, although sites that were in pasture for > 10 yr had significantly lower species richness. Forest cover near the sites at the time of forest establishment did not significantly impact biomass or species richness, and the species composition of older secondary forest sites (>30 yr) converged with that of old growth. These results emphasize the resilience of tropical ecosystems in this region and the high conservation value of secondary forests.