Amount Of Mature Forest Research Articles

Evidence of time-lag in the provision of ecosystem services by tropical regenerating forests to coffee yields

Restoration of native tropical forests is crucial for protecting biodiversity and ecosystem functions, such as carbon stock capacity. However, little is known about the contribution of early stages of forest regeneration to crop productivity through the enhancement of ecosystem services, such as crop pollination and pest control. Using data from 610 municipalities along the Brazilian Atlantic Forest (30 m spatial resolution), we evaluated if young regenerating forests (YRFs) (less than 20 years old) are positively associated with coffee yield and whether such a relationship depends on the amount of preserved forest in the surroundings of the coffee fields. We found that regenerating forest alone was not associated with variations in coffee yields. However, the presence of YRF (within a 500 m buffer) was positively related to higher coffee yields when the amount of preserved forest in a 2 km buffer is above a 20% threshold cover. These results further reinforce that regional coffee yields are influenced by changes in biodiversity-mediated ecosystem services, which are explained by the amount of mature forest in the surrounding of coffee fields. We argue that while regenerating fragments may contribute to increased connectivity between remnants of forest fragments and crop fields in landscapes with a minimum amount of forest (20%), older preserved forests (more than 20 years) are essential for sustaining pollinator and pest enemy’s populations. These results highlight the potential time lag of at least 20 years of regenerating forests’ in contributing to the provision of ecosystem services that affect coffee yields (e.g. pollination and pest control). We emphasize the need to implement public policies that promote ecosystem restoration and ensure the permanence of these new forests over time.

Metabarcoding reveals landscape drivers of beetle community composition approximately 50 years after timber harvesting

Landscape conservation planning in managed forests requires information on the relative importance of different aspects of mature forests. Regeneration forest sites with greater access to source populations for re-establishment of biodiversity are expected to have greater similarity in species composition to unharvested mature areas, i.e., when sites are in close proximity to mature forest (forest influence), and/or have a high percentage of mature forest in the surrounding landscape (landscape context). We investigated how recovery of ground-active beetle biodiversity in the mid-late successional stage (40–58 years) of previously harvested regeneration forests is affected by forest influence, landscape context, and other characteristics of the surrounding landscape. We used DNA metabarcoding to characterise beetle communities in 12 mature forest sites and 64 regeneration forest sites. Generalized dissimilarity modelling (GDM), constrained redundancy analysis, and ordinations evaluated the contribution of predictors (i.e., bioclimate, landscape configuration, regeneration age, spatial position and topography) to beetle composition. Beetle composition was significantly different between different forest ages and landscape context classes. GDM of all predictors explained 34.1% of total variance in beetle community turnover. While the geographic locations of sites accounted for most (75.1%) of composite ecological gradients, the beetle community is subtly influenced by the effects of landscape context (1.8%), forest influence (1.2%) and other variables relating to landscape configuration (collectively 5.2%). Long-term conservation of local biodiversity in managed forests requires maintaining a certain amount of mature forest, but their importance as beetle source populations declines as the regeneration forests mature.

Occupancy Models of Nesting‐Season Habitat Associations of Red‐Shouldered Hawks in Central Minnesota

ABSTRACT Red‐shouldered hawks (Buteo lineatus) are a species of special conservation concern in much of the Great Lakes region, and apparent population declines are thought to be primarily due to habitat loss and alteration. To evaluate red‐shouldered hawk‐habitat associations during the nesting season and at the landscape scale, we conducted repeated call‐broadcast surveys in central Minnesota, USA, across 3 landscapes that represented a range of landscape conditions as a result of differing management practices. In 2004, we conducted repeated call‐broadcast surveys at 131 locations in 2 study areas, and in 2005, we surveyed 238 locations in 3 study areas. We developed models relating habitat characteristics at 2 spatial scales to red‐shouldered hawk occupancy and assessed support for these models in an information‐theoretic framework. Overall, a small proportion of nonforest (grass, clear‐cut area, forest <5 yr old), and a large proportion of mature deciduous forest (>40 yr old), had the strongest association with red‐shouldered hawk occupancy (proportion of sites occupied) at both spatial scales. The landscape conditions we examined appeared to contain a habitat transition important to red‐shouldered hawks. We found, in predominately forest landscapes, the amount of open habitat was most strongly associated with red‐shouldered hawk occupancy, but in landscapes that included slightly less mature forest and more extensive open habitats, the extent of mature deciduous forest was most strongly associated with red‐shouldered hawk occupancy. Our results suggested that relatively small (<5 ha) patches of open habitat (clear‐cuts) in otherwise forested landscapes did not appear to influence red‐shouldered hawk occupancy. Whereas, in an otherwise similar landscape, with smaller amounts of mature deciduous forest and larger (>15 ha) patches of open habitat, red‐shouldered hawk occupancy decreased, suggesting a threshold in landscape composition, based on both the amount of mature forest and open area, is important in managing forest landscapes for red‐shouldered hawks. Our results show that during the nesting season, red‐shouldered hawks in central Minnesota occupy at similar rates landscapes with different habitat compositions resulting from different management strategies and that management strategies that create small openings may not negatively affect red‐shouldered hawk occupancy.

The age and amount of regrowth forest in fragmented brigalow landscapes are both important for woodland dependent birds

In highly-modified agricultural landscapes, regrowth (secondary) forest on abandoned farmland offers the potential for passive landscape restoration for biodiversity conservation. While numerous studies have investigated the ecological values of regrowth for fauna recovery at the local-level (1–10 ha), there is a dearth of studies quantifying the contribution of regrowth forest at the landscape-level (100–1000s ha). To address this critical knowledge gap we question how the age and amount of regrowth forest in the landscape influence species richness and abundance of mature forest dependent species? Using woodland dependent birds in fragmented sub-tropical brigalow landscapes in southern Queensland, Australia, we applied model averaging and hierarchical partitioning analyses to test and rank the relative importance of the amount of regrowth forest in the landscape in three age classes (<15, 15–30, and >30 years) compared to local (grazing disturbance, abundance of aggressive miners, mistletoe abundance and patch age) and landscape measures of habitat (amount of mature forest and number of mature forest patches). Response variables included the species richness of woodland dependent birds and sub-groupings of foraging guilds, and the abundance of selected individual species. The importance of explanatory variables differed considerably among response groups. Local attributes, such as patch age and the abundance of mistletoe plants, had the strongest influences on woodland dependent birds. However, we found that the amount of regrowth forest, particularly >30 years, also had a strong influence on both species richness and abundance. This study confirms that regrowth, especially older regrowth, can make an important contribution to landscape restoration in highly-modified agricultural landscapes.

Golden lion tamarin sleeping‐site use and pre‐retirement behavior during intense predation

Sleeping sites, their patterns of use, and cryptic pre-retirement behavior mitigate predation risk at sleeping sites and could influence prey fitness. We evaluated sleeping-site usage for 10 groups of golden lion tamarins (GLTs) from a population that recently suffered a substantial decline due to predation at sleeping sites. We recorded the average number of nights that groups spent at their different sleeping sites to determine whether patterns of sleeping-site use were influenced by predation risk, as measured by the rate of encounters with predators, or the availability of suitable sleeping sites, as measured by the size of a group's home range and amount of mature forest within their home range. In addition, we measured travel speed to sleeping sites and compared this speed with that recorded at other times of day. GLT groups spent more nights on average at each of their sleeping sites compared to other callitrichid species for which data are available. Predation risk and habitat characteristics were not significant predictors of how many times groups used each of their different sleeping sites. Groups significantly increased their travel speed just before entering the sleeping site. Rapid locomotion to secure tree cavities may help GLTs avoid crepuscular and nocturnal predators; however, we speculate that this strategy failed numerous GLTs in our study population during the previous decade because they used sleeping sites that were accessible to predators.

A dynamic model of household decision-making and parcel level landcover change in the eastern Amazon

The region around Altamira, Brazil, located in the Eastern Amazon, has experienced rapid landcover change since the initiation of government sponsored colonization projects associated with the construction of the Trans-Amazon Highway. The 30 years since colonization (1971) have been marked by a net loss of forest cover and an increase in the amount of cultivated/productive land, particularly for pasture and annual/perennial crop production. This research presents a parcel-level model of landcover change for smallholders in the Altamira study area. The utility of specific land-use activities is calculated to identify those land-uses that are most optimal at each time point, and labor is allocated to these activities based on the availability of household and wage labor. The model reports the proportion of the parcel in the following landcover classes at each time point using a 1-year interval: mature forest, secondary successional forest, perennial crops, annual crops and pasture. A graphical user interface is used for scenario testing, such as the impact of high/low (population) fertility, the increase of out-migration to urban areas, or changes in cattle and crop prices. The model shows a rapid reduction in the amount of mature forest in the 30 years following initial settlement, after which the parcel is composed of a mosaic of secondary succession, pasture and crops. The nature and rapidity of this landcover change is the function of a variety of household and external variables incorporated in the model. In particular, the model produces different landcover compositions as a function of demographic rates (fertility, mortality) and agricultural prices.