Habitat fragmentation and its lasting impact on Earth’s ecosystems
- N. Haddad, L. Brudvig, J. Townshend
- Environmental ScienceScience Advances
- 1 March 2015
An analysis of global forest cover is conducted to reveal that 70% of remaining forest is within 1 km of the forest’s edge, subject to the degrading effects of fragmentation, indicating an urgent need for conservation and restoration measures to improve landscape connectivity.
Plant species loss decreases arthropod diversity and shifts trophic structure.
- N. Haddad, G. Crutsinger, K. Gross, J. Haarstad, J. Knops, D. Tilman
- Environmental ScienceEcology Letters
- 1 October 2009
The results demonstrate that, over the long term, the loss of plant species propagates through food webs, greatly decreasing arthropod species richness, shifting a predator-dominated trophic structure to being herbivore dominated, and likely impacting ecosystem functioning and services.
Effects of plant species richness on invasion dynamics, disease outbreaks, insect abundances and diversity.
Experimental reductions in grassland plant richness increase ecosystem vulnerability to invasions by plant species, enhance the spread of plant fungal diseases, and alter the richness and structure of insect communities, suggesting that the loss of basal species may have profound effects on the integrity and functioning of ecosystems.
The effects of long-term nitrogen loading on grassland insect communities
- N. Haddad, J. Haarstad, D. Tilman
- Environmental ScienceOecologia
- 1 July 2000
It is demonstrated that long-term nitrogen loading affects the entire food chain, simplifying both plant and insect communities.
Contrasting Effects of Plant Richness and Composition on Insect Communities: A Field Experiment
- N. Haddad, D. Tilman, J. Haarstad, M. Ritchie, J. Knops
- Environmental ScienceAmerican Naturalist
- 1 July 2001
In insect communities, insect species richness increased as plant species richness and plant functional group richness increased, and both factors may explain how the loss of plant diversity influences higher trophic levels.
CORRIDOR AND DISTANCE EFFECTS ON INTERPATCH MOVEMENTS: A LANDSCAPE EXPERIMENT WITH BUTTERFLIES
- N. Haddad
- Environmental Science
- 1 May 1999
The hypothesis that corridors increase animal movement between habitat fragments, a central tenet of conservation biology, is demonstrated and the results suggest that corridors will increase long-distance movements of habitat-restricted species.
Corridors affect plants, animals, and their interactions in fragmented landscapes
- J. Tewksbury, D. Levey, Patricia A. Townsend
- Environmental ScienceProceedings of the National Academy of Sciences…
- 18 September 2002
It is demonstrated that corridors not only increase the exchange of animals between patches, but also facilitate two key plant–animal interactions: pollination and seed dispersal, and suggested that increased plant and animal movement through corridors will have positive impacts on plant populations and community interactions in fragmented landscapes.
Corridor Use Predicted from Behaviors at Habitat Boundaries
- N. Haddad
- Environmental ScienceAmerican Naturalist
- 1 February 1999
This study suggests that corridors direct movements of habitat‐restricted species and that local behaviors may be used to predict the conservation potential of corridors in fragmented landscapes.
AN EXPERIMENTAL TEST OF CORRIDOR EFFECTS ON BUTTERFLY DENSITIES
It is found that three habitat-restricted butterfly species reached higher densities in patches connected by corridors than in similar, isolated patches, and plant densities did not confound corridor effects on butterfly densities.
BIRD ASSEMBLAGES IN PATCHY WOODLANDS: MODELING THE EFFECTS OF EDGE AND MATRIX HABITATS
- T. Sisk, N. Haddad, P. Ehrlich
- Environmental Science
- 1 November 1997
A spatial model, the Effective Area Model (EAM), is developed that predicts the effects of matrix habitats on species abundances in habitat patches, an improvement over models that do not account for the influence of surrounding habitats on the distribution and abundance of animals in small habitat patches.
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