Richard S. Condit results 26
· Newest (Page 1/2, per page 25)
Author: Richard S. Condit ×Clear All Filters
Search Results
Putting seedlings on the map: Trade‐offs in demographic rates between ontogenetic size classes in five tropical forestsNARA Subscribed
All species must partition resources among the processes that underly growth, survival, and reproduction. The resulting demographic trade‐offs constrain the range of viable life‐history strategies and are hypothesized to promote local coexistence. Tropical forests pose ideal systems to study demographic trade‐offs as they have a high diversity of coexisting tree species whose life‐history strategies tend to align along two ort...
Physiological tipping points in the relationship between foraging success and lifetime fitness of a long‐lived mammalNARA Subscribed
Although anthropogenic change is often gradual, the impacts on animal populations may be precipitous if physiological processes create tipping points between energy gain, reproduction or survival. We use 25 years of behavioural, diet and demographic data from elephant seals to characterise their relationships with lifetime fitness. Survival and reproduction increased with mass gain during long foraging trips preceding the pupp...
RecruitNet : A global database of plant recruitment networksNARA Subscribed
Plant recruitment interactions (i.e., what recruits under what) shape the composition, diversity, and structure of plant communities. Despite the huge body of knowledge on the mechanisms underlying recruitment interactions among species, we still know little about the structure of the recruitment networks emerging in ecological communities. Modeling and analyzing the community‐level structure of plant recruitment interactions...
Northern elephant seals migrate long distances from feeding grounds to raise pups during a brief period on breeding beaches. Because gestation sets a parturition date months in advance, timing of the arrival must be precise; an early arrival would waste foraging time, but a late arrival would cause parturition failure. We used satellite‐tracked animals to examine this timing, establishing arrival and birth dates in 106 migrati...
Functional biogeography of Neotropical moist forests: Trait–climate relationships and assembly patterns of tree communitiesNARA Subscribed
Aim Here we examine the functional profile of regional tree species pools across the latitudinal distribution of Neotropical moist forests, and test trait–climate relationships among local communities. We expected opportunistic strategies (acquisitive traits, small seeds) to be overrepresented in species pools further from the equator, but also in terms of abundance in local communities in currently wetter, warmer and more sea...
Counting niches: Abundance‐by‐trait patterns reveal niche partitioning in a Neotropical forestNARA Subscribed
Tropical forests challenge us to understand biodiversity, as numerous seemingly similar species persist on only a handful of shared resources. Recent ecological theory posits that biodiversity is sustained by a combination of species differences reducing interspecific competition and species similarities increasing time to competitive exclusion. Together, these mechanisms counterintuitively predict that competing species shoul...
Seed‐to‐seedling transitions exhibit distance‐dependent mortality but no strong spacing effects in a Neotropical forestNARA Subscribed
Patterns of seed dispersal and seed mortality influence the spatial structure of plant communities and the local coexistence of competing species. Most seeds are dispersed in proximity to the parent tree, where mortality is also expected to be the highest, because of competition with siblings or the attraction of natural enemies. Whereas distance‐dependent mortality in the seed‐to‐seedling transition was often observed in trop...
Temporal population variability in local forest communities has mixed effects on tree species richness across a latitudinal gradientNARA Subscribed
Among the local processes that determine species diversity in ecological communities, fluctuation‐dependent mechanisms that are mediated by temporal variability in the abundances of species populations have received significant attention. Higher temporal variability in the abundances of species populations can increase the strength of temporal niche partitioning but can also increase the risk of species extinctions, such that...
Aim Large tropical trees form the interface between ground and airborne observations, offering a unique opportunity to capture forest properties remotely and to investigate their variations on broad scales. However, despite rapid development of metrics to characterize the forest canopy from remotely sensed data, a gap remains between aerial and field inventories. To close this gap, we propose a new pan‐tropical model to predic...
Resolving the paradox of clumped seed dispersal: positive density and distance dependence in a bat‐dispersed speciesNARA Subscribed
One of the hypothesized benefits of seed dispersal is to escape density‐ and distance‐responsive, host‐specific, natural enemies near maternal plants where conspecific seed and seedling densities are high. Such high conspecific neighbor densities typically result in lower offspring growth and survival (i.e., negative density‐dependent effects), yet many dispersal modes result in clumped seed distributions. New World leaf‐nosed...
Motivation The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community‐led open‐source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal...
Front CoverNARA Subscribed
Global importance of large‐diameter treesNARA Subscribed
Aim To examine the contribution of large‐diameter trees to biomass, stand structure, and species richness across forest biomes. Location Global. Time period Early 21st century. Major taxa studied Woody plants. Methods We examined the contribution of large trees to forest density, richness and biomass using a global network of 48 large (from 2 to 60 ha) forest plots representing 5,601,473 stems across 9,298 species and 210 plan...
Beyond the fast–slow continuum: demographic dimensions structuring a tropical tree communityNARA Subscribed
Life‐history theory posits that trade‐offs between demographic rates constrain the range of viable life‐history strategies. For coexisting tropical tree species, the best established demographic trade‐off is the growth‐survival trade‐off. However, we know surprisingly little about co‐variation of growth and survival with measures of reproduction. We analysed demographic rates from seed to adult of 282 co‐occurring tropical tre...
Contrasting outcomes of species‐ and community‐level analyses of the temporal consistency of functional compositionNARA Subscribed
Multiple anthropogenic drivers affect every natural community, and there is broad interest in using functional traits to understand and predict the consequences for future biodiversity. There is, however, no consensus regarding the choice of analytical methods. We contrast species‐ and community‐level analyses of change in the functional composition for four traits related to drought tolerance using three decades of repeat cen...
Temporal variability of forest communities: empirical estimates of population change in 4000 tree speciesNARA Subscribed
Long‐term surveys of entire communities of species are needed to measure fluctuations in natural populations and elucidate the mechanisms driving population dynamics and community assembly. We analysed changes in abundance of over 4000 tree species in 12 forests across the world over periods of 6–28 years. Abundance fluctuations in all forests are large and consistent with population dynamics models in which temporal environme...
Functional traits explain light and size response of growth rates in tropical tree speciesNARA Subscribed
Relationships between functional traits and average or potential demographic rates have provided insight into the functional constraints and trade‐offs underlying life‐history strategies of tropical tree species. We have extended this framework by decomposing growth rates of ∼130 000 trees of 171 Neotropical tree species into intrinsic growth and the response of growth to light and size. We related these growth characteristics...
A trade‐off between growth and mortality rates characterizes tree species in closed canopy forests. This trade‐off is maintained by inherent differences among species and spatial variation in light availability caused by canopy‐opening disturbances. We evaluated conditions under which the trade‐off is expressed and relationships with four key functional traits for 103 tree species from Barro Colorado Island, Panama. The trade‐...
The effect of climatic gradients, topographic variation and species traits on the beta diversity of rain forest treesNARA Subscribed
Aim We assessed the rates of turnover of tree species with distance (beta diversity) in wet forests of the Western Ghats (WG) complex of India to see whether climate, topographic variation or species traits influence beta diversity. Location The Western Ghats is a chain of mountains about 1600 km in length, running parallel to the western coast of the Indian Peninsula from above 8° N to almost 21° N latitude. Methods We used d...
Testing metabolic ecology theory for allometric scaling of tree size, growth and mortality in tropical forestsNARA Subscribed
The theory of metabolic ecology predicts specific relationships among tree stem diameter, biomass, height, growth and mortality. As demographic rates are important to estimates of carbon fluxes in forests, this theory might offer important insights into the global carbon budget, and deserves careful assessment. We assembled data from 10 old‐growth tropical forests encompassing censuses of 367 ha and > 1.7 million trees to test...
Comparing tropical forest tree size distributions with the predictions of metabolic ecology and equilibrium modelsNARA Subscribed
Tropical forests vary substantially in the densities of trees of different sizes and thus in above‐ground biomass and carbon stores. However, these tree size distributions show fundamental similarities suggestive of underlying general principles. The theory of metabolic ecology predicts that tree abundances will scale as the −2 power of diameter. Demographic equilibrium theory explains tree abundances in terms of the scaling o...