Deforestation drives functional diversity and fruit quality changes in a tropical tree assemblage

Functional traits associated with plant-animal interactions are essential for forest functionality, given that a higher diversity of fruit traits is likely to maintain a more diverse assemblage of frugivores and consequently promote the seed dispersal function. Yet, shade-intolerant species tend to persist in human-modified landscapes in the long term, which in turn is expect to reduce fruit trait diversity. Here we evaluate how forest cover at the landscape-scale influences the functional diversity of fruit traits, considering the zoochoric tree community and two regeneration strategies separately (shade-tolerant and shade-intolerant species). We sampled 20 forest remnants in the Brazilian Atlantic Forest, located in landscapes with forest cover ranging from 2 to 93%. In each remnant, we established five plots of 25 ×4 m and marked all trees≥5 cm diameter at breast height (DBH). We compared morphological and chemical attributes of fleshy fruits directly related to the attraction of frugivores, and evaluated the similarity of the zoochoric tree assemblage composition along the forest cover gradient, taking into account the two regeneration strategies. We calculated four functional indices (richness, evenness, divergence, and community-level weighted means of trait values) and used either linear models or spatial mixed linear models to evaluate the effects of forest cover on functional diversity. Our main results revealed that forest cover loss has negatively affected fruit functional diversity for the overall zoochoric community. Forest cover loss also affected functional richness and functional evenness for total and shade-tolerant species, and was positively correlated with the content of protein and lipid in fruits of shade-intolerant species. Additionally, sites exhibiting a lower amount of forest cover showed greater compositional similarity among shade-intolerant species but reduced similarity among shade-tolerant species. We conclude that patterns of species reassembly triggered by landscape-scale deforestation decreases the capacity of the remaining forest for provisioning food resources for frugivore assemblages. The maintenance of shade-tolerant species is pivotal in deforested areas, since their fruit quality is not offset by shade-intolerant species. This is particularly important, mainly because shade-intolerant species are those still persisting in disturbed forests; however, their presence will not provide the same food quality supplied by those species lost.Sisbiota (grant numbers 563216/2010-7); Universal (grant numbers 481400/2011-7); PROPP (grant numbers 00220.1100.02); CAPES (grant numbers 015/2014); FAPESB (grant numbers JCB0049/2013

Data from: The loss of functional diversity: a detrimental influence of landscape-scale deforestation on tree reproductive traits

1. Agricultural activities such as crop production and cattle ranching are rapidly replacing forests worldwide, especially in the tropics. Resulting forest loss can adversely affect biodiversity in many ways, including trajectories of community reassembly, community composition, forest structural profiles, and taxonomic diversity. Yet, effects of forest loss on specific ecosystem functions remain limited. Processes closely linked with tree reproduction, such as pollination and seed dispersal are of paramount importance for many ecological functions in tropical forests. Disruption in these processes is known to delay or change forest regeneration, diversity, and structural dynamics. 2. To explore how reproductive and dispersal traits are being altered by landscape-scale deforestation, we surveyed and compiled trait data for tree communities in 20 tropical Atlantic rainforest remnants in northeastern Brazil, across a gradient of deforested landscapes, each retaining 3 to 93% forest cover. 3. The functional richness of reproductive plant attributes decreased as the amount of forest cover decreased, while divergence increased along the same gradient. Loss of forest cover disproportionately affected certain dispersal and reproductive attributes, with most heavily impacted functional attributes including: brief flowering duration, hermaphrodite sexual system, and zoochoric dispersal mode. We identified a clear threshold at 25-30% of forest cover, below which, reproductive attributes disappeared more quickly than expect from forest remnants. 4. Synthesis. Deforestation may impair tree community functional diversity, particularly by decreasing the number of functions and increasing certain functional reproductive attributes that are particularly successful in disturbed habitats. Under scenarios of extensive deforestation, changes to reproductive and dispersal trait profile of forest communities suggest that profound modifications in the availability of floral and seed resources are likely to be substantial. Such extensive changes to food supply of pollinating and dispersing animals suggest carry-over effects to the fauna of these important forest systems

The loss of functional diversity: a detrimental influence of landscape‐scale deforestation on tree reproductive traits

Agricultural activities such as crop production and cattle ranching are rapidly replacing forests worldwide, especially in the tropics. Resulting forest loss can adversely affect biodiversity in many ways, including trajectories of community reassembly, community composition, forest structural profiles and taxonomic diversity. Yet, effects of forest loss on specific ecosystem functions remain limited. Processes closely linked with tree reproduction, such as pollination and seed dispersal are of paramount importance for many ecological functions in tropical forests. Disruption in these processes is known to delay or change forest regeneration, diversity and structural dynamics. To explore how reproductive and dispersal traits are being altered by landscape-scale deforestation, we surveyed and compiled trait data for tree communities in 20 tropical Atlantic rainforest remnants in northeastern Brazil, across a gradient of deforested landscapes, each retaining 3%–93% forest cover. The functional richness of reproductive plant attributes decreased as the amount of forest cover decreased, while divergence increased along the same gradient. Loss of forest cover disproportionately affected certain dispersal and reproductive attributes, with most heavily impacted functional attributes including: brief flowering duration, hermaphrodite sexual system, and zoochoric dispersal mode. We identified a clear threshold at 25–30% of forest cover, below which, reproductive attributes disappeared more quickly than expect from forest remnants. Synthesis. Deforestation may impair tree community functional diversity, particularly by decreasing the number of functions. Under scenarios of extensive deforestation, changes to reproductive and dispersal trait profile of forest communities suggest that profound modifications in the availability of floral and seed resources are likely to be substantial. Such extensive changes to food supply of pollinating and dispersing animals suggest carry-over effects to the fauna of these important forest systems

Functional decay in tree community within tropical fragmented landscapes: Effects of landscape-scale forest cover

<div><p>As tropical rainforests are cleared, forest remnants are increasingly isolated within agricultural landscapes. Understanding how forest loss impacts on species diversity can, therefore, contribute to identifying the minimum amount of habitat required for biodiversity maintenance in human-modified landscapes. Here, we evaluate how the amount of forest cover, at the landscape scale, affects patterns of species richness, abundance, key functional traits and common taxonomic families of adult trees in twenty Brazilian Atlantic rainforest landscapes. We found that as forest cover decreases, both tree community richness and abundance decline, without exhibiting a threshold. At the family-level, species richness and abundance of the Myrtaceae and Sapotaceae were also negatively impacted by the percent forest remaining at the landscape scale. For functional traits, we found a reduction in shade-tolerant, animal-dispersed and small-seeded species following a decrease in the amount of forest retained in landscapes. These results suggest that the amount of forest in a landscape is driving non-random losses in phylogenetic and functional tree diversity in Brazil’s remaining Atlantic rainforests. Our study highlights potential restraints on the conservation value of Atlantic rainforest remnants in deforested landscapes in the future.</p></div

Relationships between forest cover with the species richness for each of the most common families recorded (Myrtaceae—Myr, Fabaceae—Fab, Lauraceae—Lau, Rubiaceae—Rub and Sapotaceae—Sap).

<p>Plotted curves represent all well-supported models (null, linear, power-law and logistic model) for each relationship.</p

Relationships between forest cover amount with the species richness of shade-intolerant, shade-intolerance, abiotic-dispersed, biotic-dispersed, small-seeded and large-seeded species.

<p>Plotted curves represent of all well-supported models (null, linear, power-law and logistic model) identified with AICc for each relationship.</p

Detrended Correspondence Analysis (DCA) ordinations on the quantitative tree species composition.

<p>Detrended Correspondence Analysis (DCA) ordinations on the quantitative tree species composition.</p

Relationships between forest cover amount with the overall species richness and overall abundance (number of individuals).

<p>Plotted curves represent all well-supported models (null, linear, power-law and logistic model) identified with AICc for each relationship. Logistic models were excluded for spatial linear models (see text for details).</p

Coefficients and significance of the most parsimonious model (determined by AICc) for richness and abundance of the overall tree community and for the most important families in our study.

<p>Coefficients and significance of the most parsimonious model (determined by AICc) for richness and abundance of the overall tree community and for the most important families in our study.</p